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Search Results (986)

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Keywords = sirtuins

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18 pages, 1640 KiB  
Article
The Clinical Role of SIRT-3 in the Acute Rejection Process of Kidney Transplantation and Its Effects on Graft Outcomes: Evaluation of Biomarker Potential
by Necip Altundaş, Eda Balkan, Murat Kizilkaya, Murat Altunok, Elif Demirci, Nurhak Aksungur, Salih Kara, Gürkan Öztürk and Abdullah Uyanik
Medicina 2025, 61(3), 457; https://doi.org/10.3390/medicina61030457 - 6 Mar 2025
Viewed by 242
Abstract
Background and Objectives: The aim of this study was to investigate the changes in the SIRT family, the effects of sirtuins on kidney graft function, and their potential as biomarkers in patients who develop rejection after kidney transplantation. Materials and Methods: [...] Read more.
Background and Objectives: The aim of this study was to investigate the changes in the SIRT family, the effects of sirtuins on kidney graft function, and their potential as biomarkers in patients who develop rejection after kidney transplantation. Materials and Methods: Blood samples were collected from 45 kidney transplant patients before and after rejection. Some of these patients experienced T-cell-mediated early rejection (TCMR), while others presented antibody-mediated late rejection (ABMR). The mRNA expression levels of SIRT-1, SIRT-3, and SIRT-7 were measured via real-time PCR, while the protein levels of SIRT-1, SIRT-2, SIRT-3, SIRT-5, and SIRT-7 were assessed using ELISA. Patients were grouped based on rejection type and histological characteristics. Statistical analyses were performed using SPSS software (V23). Results: The mean age of the patient group was 42.22, while the control group had a mean age of 35.23 (p = 0.002). SIRT-1, SIRT-3, and SIRT-7 levels were significantly higher in patients with rejection (p < 0.001). In patients with late-stage rejection, SIRT-3 was found to be associated with interstitial fibrosis and C4d accumulation. SIRT-7 levels showed a weak correlation with potassium levels (p = 0.014). Conclusions: Our findings demonstrate significant changes in the SIRT family during both early- and late-stage rejection processes. Particularly, the role of SIRT-3 in the late stage is highlighted, suggesting the potential use of this gene as a biomarker for managing rejection processes. These findings could provide valuable insights for developing treatment strategies in organ transplantation. Full article
(This article belongs to the Section Surgery)
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Figure 1
<p>SIRT values according to groups: (<b>a</b>) SIRT-1 values; (<b>b</b>) SIRT-2 values; (<b>c</b>) SIRT-3 values; (<b>d</b>) SIRT-5 values; (<b>e</b>) SIRT-6 values; and (<b>f</b>) SIRT-7 values.</p>
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<p>ROC curve for ELISA variables in disease detection.</p>
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<p>ROC curve for mRNA variables in disease detection.</p>
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<p>SIRT values according to groups. (<b>a</b>) SIRT-1 values. (<b>b</b>) SIRT-3 values. (<b>c</b>) SIRT-6 values.</p>
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23 pages, 3878 KiB  
Article
Synergistic Neuroprotection Through Epigenetic Modulation by Combined Curcumin-Enriched Turmeric Extract and L-Ascorbic Acid in Oxidative Stress-Induced SH-SY5Y Cell Damage
by Jurairat Khongrum, Nootchanat Mairuae, Tongjit Thanchomnang, Man Zhang, Gang Bai and Nut Palachai
Foods 2025, 14(5), 892; https://doi.org/10.3390/foods14050892 - 5 Mar 2025
Viewed by 236
Abstract
Epigenetic modulation plays a crucial role in neuroprotection by regulating cellular responses to stress, inflammation, and oxidative damage, particularly in neurodegenerative diseases. Recognizing the therapeutic potential of epigenetic regulators, this study investigated the synergistic neuroprotective effects of curcumin-enriched turmeric extract combined with L-ascorbic [...] Read more.
Epigenetic modulation plays a crucial role in neuroprotection by regulating cellular responses to stress, inflammation, and oxidative damage, particularly in neurodegenerative diseases. Recognizing the therapeutic potential of epigenetic regulators, this study investigated the synergistic neuroprotective effects of curcumin-enriched turmeric extract combined with L-ascorbic acid, focusing on its modulation of epigenetic pathways in oxidative stress-induced neuronal damage. SH-SY5Y neuronal cells were treated with the combination at 20 and 40 µg/mL, and subsequently exposed to 200 µM hydrogen peroxide (H2O2) to induce oxidative stress. Cell viability was assessed using the MTT assay, while neuroprotective mechanisms were evaluated by analyzing the markers of epigenetic modulation, oxidative stress, inflammation, and apoptosis. The combination significantly enhanced cell viability, upregulated sirtuin-1 (SIRT1), and reduced DNA methyltransferase 1 (DNMT1) expression, indicating effective epigenetic modulation. Enhanced antioxidant defenses were observed, as evidenced by increased activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), along with decreased malondialdehyde (MDA) and reactive oxygen species (ROS) levels, alleviating oxidative stress. Additionally, it suppressed nuclear factor kappa B (NF-κB) activity and its downstream mediator interleukin-6 (IL-6), thereby mitigating inflammation. The treatment also increased anti-apoptotic Bcl-2 expression while reducing pro-apoptotic markers, including caspase-3 and caspase-9, suggesting inhibition of the intrinsic apoptotic pathway. These findings highlight the novel neuroprotective effects of this combination, demonstrating its ability to modulate epigenetic pathways while reducing oxidative stress, suppressing inflammation, and preventing undesired apoptosis. Its multifaceted neuroprotective properties make it a promising functional ingredient in functional foods for neurodegenerative disease intervention. However, further investigations, including animal studies and clinical trials, are essential to evaluate its safety and therapeutic potential. Full article
(This article belongs to the Section Food Nutrition)
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<p>Cytotoxicity of curcumin-enriched turmeric extract combined with L-ascorbic acid on the viability of SH-SY5Y cells. Data are presented as the mean ± SEM. *, **, *** <span class="html-italic">p</span> &lt; 0.05, 0.01, and 0.001, respectively; compared with the naïve control (0 µg/mL).</p>
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<p>Neuroprotective effects of curcumin-enriched turmeric extract combined with L-ascorbic acid on H<sub>2</sub>O<sub>2</sub>-induced oxidative damage in SH-SY5Y cells. (<b>A</b>) Representative images of SH-SY5Y cell density at 10× magnification. (<b>B</b>) Percentage of cell viability. Data are presented as the mean ± SEM. *** <span class="html-italic">p</span> &lt; 0.001; compared with the naïve control group, <sup>###</sup> <span class="html-italic">p</span> &lt; 0.001; compared with the H<sub>2</sub>O<sub>2</sub> and vehicle-treated group. H<sub>2</sub>O<sub>2</sub>: 200 µM hydrogen peroxide; CC: curcumin-enriched turmeric extract combined with L-ascorbic acid.</p>
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<p>Effect of curcumin-enriched turmeric extract combined with L-ascorbic acid on epigenetic modulation in oxidative stress-induced SH-SY5Y cell damage. (<b>A</b>) Immunoblot showing the expression of SIRT1 and DNMT1. (<b>B</b>) Relative density of SIRT1, normalized to beta-actin. (<b>C</b>) Relative density of DNMT1, normalized to beta-actin. Data are presented as the mean ± SEM. **, *** <span class="html-italic">p</span> &lt; 0.01 and 0.001, respectively; compared with the naïve control group, <sup>##</sup>, <sup>###</sup> <span class="html-italic">p</span> &lt; 0.01 and 0.001, respectively; compared with the H<sub>2</sub>O<sub>2</sub> and vehicle-treated group. H<sub>2</sub>O<sub>2</sub>: 200 µM hydrogen peroxide; CC: curcumin-enriched turmeric extract combined with L-ascorbic acid.</p>
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<p>Effect of curcumin-enriched turmeric extract combined with L-ascorbic acid on ROS generation in oxidative stress-induced SH-SY5Y cell damage. Data are presented as the mean ± SEM. *** <span class="html-italic">p</span> &lt; 0.001; compared with the naïve control group; <sup>###</sup> <span class="html-italic">p</span> &lt; 0.001; compared with the H<sub>2</sub>O<sub>2</sub> and vehicle-treated group. H<sub>2</sub>O<sub>2</sub>: 200 µM hydrogen peroxide; CC: curcumin-enriched turmeric extract combined with L-ascorbic acid.</p>
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<p>Effect of curcumin-enriched turmeric extract combined with L-ascorbic acid on MDA level in oxidative stress-induced SH-SY5Y cell damage. Data are presented as the mean ± SEM. ** <span class="html-italic">p</span> &lt; 0.01; compared with the naïve control group; <sup>#</sup> <span class="html-italic">p</span> &lt; 0.05; compared with the H<sub>2</sub>O<sub>2</sub> and vehicle-treated group. H<sub>2</sub>O<sub>2</sub>: 200 µM hydrogen peroxide; CC: curcumin-enriched turmeric extract combined with L-ascorbic acid.</p>
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<p>Effect of curcumin-enriched turmeric extract combined with L-ascorbic acid on antioxidant enzyme activities in oxidative stress-induced SH-SY5Y cell damage. Data are presented as the mean ± SEM. *** <span class="html-italic">p</span> &lt; 0.001; compared with the naïve control group; <sup>#</sup>, <sup>###</sup> <span class="html-italic">p</span> &lt; 0.05 and 0.001, respectively; compared with the H<sub>2</sub>O<sub>2</sub> and vehicle-treated group. H<sub>2</sub>O<sub>2</sub>: 200 µM hydrogen peroxide; CC: curcumin-enriched turmeric extract combined with L-ascorbic acid.</p>
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<p>Effect of curcumin-enriched turmeric extract combined with L-ascorbic acid on inflammatory markers in oxidative stress-induced SH-SY5Y cell damage. (<b>A</b>) Immunoblot showing the expression of NF-κB and IL-6. (<b>B</b>) Relative density of NF-κB, normalized to beta-actin. (<b>C</b>) Relative density of IL-6, normalized to beta-actin. Data are presented as the mean ± SEM. **, *** <span class="html-italic">p</span> &lt; 0.01 and 0.001, respectively; compared with the naïve control group, <sup>#</sup>, <sup>##</sup> <span class="html-italic">p</span> &lt; 0.05 and 0.01, respectively; compared with the H<sub>2</sub>O<sub>2</sub> and vehicle-treated group. H<sub>2</sub>O<sub>2</sub>: 200 µM hydrogen peroxide; CC: curcumin-enriched turmeric extract combined with L-ascorbic acid.</p>
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<p>Effects of curcumin-enriched turmeric extract combined with L-ascorbic acid on apoptotic markers in H<sub>2</sub>O<sub>2</sub>-induced oxidative damage in SH-SY5Y cells. (<b>A</b>) Immunoblot showing the expression of Bcl-2, caspase-3, and caspase-9. (<b>B</b>) Relative density of Bcl-2, normalized to beta-actin. (<b>C</b>) Relative density of caspase-3, normalized to beta-actin. (<b>D</b>) Relative density of caspase-9, normalized to beta-actin. Data are presented as the mean ± SEM. *, **, *** <span class="html-italic">p</span> &lt; 0.05, 0.01, and 0.001, respectively; compared with the naïve control group, <sup>#</sup>, <sup>##</sup>, <sup>###</sup> <span class="html-italic">p</span> &lt; 0.05, 0.01, and 0.001, respectively; compared with the H<sub>2</sub>O<sub>2</sub> and vehicle-treated group. H<sub>2</sub>O<sub>2</sub>: 200 µM hydrogen peroxide; CC: curcumin-enriched turmeric extract combined with L-ascorbic acid.</p>
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<p>Effects of curcumin-enriched turmeric extract combined with L-ascorbic acid on apoptotic markers in H<sub>2</sub>O<sub>2</sub>-induced oxidative damage in SH-SY5Y cells. (<b>A</b>) Immunoblot showing the expression of Bcl-2, caspase-3, and caspase-9. (<b>B</b>) Relative density of Bcl-2, normalized to beta-actin. (<b>C</b>) Relative density of caspase-3, normalized to beta-actin. (<b>D</b>) Relative density of caspase-9, normalized to beta-actin. Data are presented as the mean ± SEM. *, **, *** <span class="html-italic">p</span> &lt; 0.05, 0.01, and 0.001, respectively; compared with the naïve control group, <sup>#</sup>, <sup>##</sup>, <sup>###</sup> <span class="html-italic">p</span> &lt; 0.05, 0.01, and 0.001, respectively; compared with the H<sub>2</sub>O<sub>2</sub> and vehicle-treated group. H<sub>2</sub>O<sub>2</sub>: 200 µM hydrogen peroxide; CC: curcumin-enriched turmeric extract combined with L-ascorbic acid.</p>
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17 pages, 2151 KiB  
Article
In Vitro Antioxidant Effects of Coenzyme Q10 on Cellular Metabolism in Aged Mesenchymal Stem Cells
by Alexandra Ivan, Alexandra Teodora Lukinich-Gruia, Iustina-Mirabela Cristea, Maria-Alexandra Pricop, Crenguta Livia Calma, Andreea Paunescu, Calin Adrian Tatu, Atena Galuscan and Virgil Paunescu
Appl. Sci. 2025, 15(5), 2783; https://doi.org/10.3390/app15052783 - 5 Mar 2025
Viewed by 157
Abstract
(1) Background: this study investigates the short-term effects of coenzyme Q10 (CoQ10) on mitochondrial respiration, fatty acid metabolism, oxidative stress gene expression, and sirtuin activity in young (passage 5, P5) and aged (passage 16, P16) mesenchymal stem cells (MSCs). (2) Methods: Mitochondrial respiration [...] Read more.
(1) Background: this study investigates the short-term effects of coenzyme Q10 (CoQ10) on mitochondrial respiration, fatty acid metabolism, oxidative stress gene expression, and sirtuin activity in young (passage 5, P5) and aged (passage 16, P16) mesenchymal stem cells (MSCs). (2) Methods: Mitochondrial respiration was assessed by measuring oxygen consumption after 24 h of treatment. Gas chromatography–mass spectrometry (GC-MS) analysis assessed cellular fatty acid methyl ester profiles. Quantitative polymerase chain reaction (qPCR) demonstrated the passage-dependent expression of oxidative stress-related genes and sirtuins in response to CoQ10 treatment. (3) Results: CoQ10 enhanced basal respiration and spare respiratory capacity (SRC), particularly in older senescent cells. CoQ10 improved basal respiration and ATP-linked oxygen consumption in young MSCs and partially restored these functions in aged MSCs. Moreover, CoQ10 increased saturated fatty acids, particularly in young cells, and decreased monounsaturated fatty acids in aged cells. qPCR analysis revealed passage-dependent modifications in oxidative stress-related genes and sirtuin expression; CoQ10 exposure significantly influenced SIRT1 and SIRT3 activity, leading to an increase in PPARγ and CAT expression. (4) Conclusions: these results highlight CoQ10’s potential to alleviate mitochondrial dysfunction and metabolic shifts associated with cellular aging, underscoring its therapeutic value for age-related mitochondrial and metabolic disorders. Full article
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<p>Cell viability assessment using the xCELLigence system. Cell index of young (P5) and old (P16) MSCs after 24 h of exposure to different concentrations of CoQ10 (10 µM, 25 µM, 50 µM, and 70 µM), (* <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.001).</p>
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<p>SA-β-gal activity in early-passage cells (P5) (<b>A</b>) and late-passage cells (P16) (<b>B</b>) following CoQ10 treatment. (<b>C</b>) Percentage of senescent cells based on the ratio of β-gal-positive cells to total cell count (*** <span class="html-italic">p</span> &lt; 0.0001).</p>
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<p>Oxygen consumption rates following CoQ10 treatment, measured using the Oroboros O2k System in early passage (P5) and late passage (P16) MSCs at concentrations of 10 µM and 50 µM CoQ10. The figure presents the impact of CoQ10 on routine respiration (R), leak respiration (L), maximum respiration (M), and spare respiratory capacity (SRC), (*** <span class="html-italic">p</span> &lt; 0.0001). Representative Oroboros oxygraphs, illustrating oxygen consumption and basal respiration measured by high-resolution respirometry, are provided in the <a href="#app1-applsci-15-02783" class="html-app">Supplementary Files (Figure S3)</a>.</p>
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<p>Antioxidant gene expression and cellular response to CoQ10 at 10 and 50 µM treatment in P5 and P16 passages, (* <span class="html-italic">p</span> &lt; 0.05, *** <span class="html-italic">p</span> &lt; 0.0001).</p>
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<p>Sirtuin gene expression response to CoQ10 across passages 5 and 16 at 10 and 50 µM treatment (* <span class="html-italic">p</span> &lt; 0.05, *** <span class="html-italic">p</span> &lt; 0.0001).</p>
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<p>Changes in FAME profiles following CoQ10 treatment. Data are presented as the mean  ±  SEM from three independent experiments. Statistical significance is denoted as follows: ** <span class="html-italic">p</span> &lt; 0.001, *** <span class="html-italic">p</span> &lt; 0.0001.</p>
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28 pages, 1378 KiB  
Review
Resveratrol and Physical Activity: A Successful Combination for the Maintenance of Health and Wellbeing?
by Mario Ruggiero, Maria Letizia Motti, Rosaria Meccariello and Filomena Mazzeo
Nutrients 2025, 17(5), 837; https://doi.org/10.3390/nu17050837 - 28 Feb 2025
Viewed by 485
Abstract
Physical exercise is an essential component of human health. In recent years, scientific research has focused on identifying natural compounds and formulating new supplements aimed at enhancing athletic performance, accelerating muscle recovery, and minimizing the damage caused by physical exertion. The use of [...] Read more.
Physical exercise is an essential component of human health. In recent years, scientific research has focused on identifying natural compounds and formulating new supplements aimed at enhancing athletic performance, accelerating muscle recovery, and minimizing the damage caused by physical exertion. The use of antioxidants to counteract the formation of reactive oxygen species (ROS) following physical activity (PA) is already a widely adopted practice. Resveratrol (RES), a polyphenol belonging to the stilbene class, is well known for its potent antioxidant activity and anti-inflammatory effects primarily attributed to the activation of sirtuins. RES possesses multiple nutraceutical properties used for the prevention and treatment of inflammatory, cardiovascular, neoplastic, and infectious diseases, thus attracting attention to study its use in combination with physical exercise to promote well-being. Animal trials combining RES and PA have mainly reported improvements in muscle, energy, and cardiovascular functions. The data presented and discussed in this narrative review are from Pubmed, Scopus, and the Human Gene Database (search limited to 2011 to 2025 with the keywords RES, sirtuins, and physical activity altogether or in combination with each other). This review gathers several studies on RES focusing on its nutraceutical properties, epigenetic activities via sirtuins, and the potential benefits of combining RES with PA in maintaining health and well-being based on trials performed first in animals and later in humans. Human studies have been conducted on various populations, including active adults, sedentary individuals, patients with diseases, and elderly individuals. Some studies have confirmed the benefits of RES observed in animal experiments. However, in some cases, no substantial differences were found between RES supplementation and the control group. In conclusion, the benefits of RES on PA reported in the literature are still not fully evident, given the contrasting studies and the still limited number of trials, but both RES and PA are successful tools for the maintenance of health and wellbeing. Full article
(This article belongs to the Section Micronutrients and Human Health)
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Graphical abstract

Graphical abstract
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<p>Dietary sources of resveratrol and their respective content (mg/100 g or mg/L) [<a href="#B68-nutrients-17-00837" class="html-bibr">68</a>].</p>
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<p>Biological and health effects of Resveratrol. AMPK, AMP-activated protein kinase; AP-1, activator protein-1; CAT, catalase; GLP-1, glucagon-like peptide 1; IGF-1, insulin-like growth factor 1; IL, interleukin; MAPK, mitogen-activated protein kinase; NF-κb, nuclear factor-Κb; NO, nitric oxide; PGC-1α, peroxisome proliferator-activated receptor-γ coactivator 1α; ROS, reactive oxygen species; SOD1, superoxide dismutase 1; TNF-α, tumor necrosis factor α; VSMC, vascular smooth muscle cell; <tt>↑, </tt>induce; <tt>↓,</tt> reduce.</p>
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17 pages, 1350 KiB  
Review
Anthocyanins and Anthocyanidins in the Management of Osteoarthritis: A Scoping Review of Current Evidence
by Xiaodong Ma, Kok-Yong Chin and Sophia Ogechi Ekeuku
Pharmaceuticals 2025, 18(3), 301; https://doi.org/10.3390/ph18030301 - 21 Feb 2025
Viewed by 296
Abstract
Background/Objectives: The consumption of food rich in anthocyanins, a natural pigment found in plants, has been associated with improved joint health. However, systematic efforts to summarise the effects of anthocyanins and their deglycosylated forms, anthocyanidins, in managing osteoarthritis (OA) are lacking. This [...] Read more.
Background/Objectives: The consumption of food rich in anthocyanins, a natural pigment found in plants, has been associated with improved joint health. However, systematic efforts to summarise the effects of anthocyanins and their deglycosylated forms, anthocyanidins, in managing osteoarthritis (OA) are lacking. This scoping review aims to comprehensively summarise the current evidence regarding the role of anthocyanins and anthocyanidins in OA management and highlights potential research areas. Methods: A comprehensive literature search was performed using PubMed, Scopus, and Web of Science in January 2025 to look for primary studies published in English, with the main objective of investigating the chondroprotective effects of anthocyanins and anthocyanidins, regardless of their study designs. Results: The seven included studies showed that anthocyanins and anthocyanidins suppressed the activation of inflammatory signalling, upregulated sirtuin-6 (cyanidin only), and autophagy (delphinidin only) in chondrocytes challenged with various stimuli (interleukin-1β, oxidative stress, or advanced glycation products). Anthocyanins also preserved cartilage integrity and increased the pain threshold in animal models of OA. No clinical trial was found in this field, suggesting a translation gap. Conclusions: In conclusion, anthocyanins and anthocyanidins are potential chondroprotective agents, but more investigations are required to overcome the gap in clinical translation. Full article
(This article belongs to the Section Natural Products)
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<p>The common forms of anthocyanidins (drawn with KingDraw).</p>
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<p>PRISMA flow chart (adapted from <a href="https://www.prisma-statement.org/prisma-2020-flow-diagram" target="_blank">https://www.prisma-statement.org/prisma-2020-flow-diagram</a>, assessed on 20 January 2025).</p>
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<p>The regulatory mechanism of anthocyanins and anthocyanidins in mitigating the progression of OA. Most anthocyanins and anthocyanidins can prevent inflammation and specific anthocyanins, such as cyanidin, which has been reported to upregulate sirtuin-6, whereas delphinidin has been reported to upregulate autophagy. (Drawn with Microsoft PowerPoint.) Abbreviations: AP-1, AP-1 transcription factor; ERK, extracellular signal-regulated kinase; IκB, I-kappa-B; JNK, c-Jun N-terminal kinase; LC3, microtubule-associated protein 1A/1B-light chain 3; MAPK, mitogen-activated protein kinase; NFκB, nuclear factor kappa-B; TRAF6, tumour necrosis factor receptor-associated factor 6; up arrow (↑), upregulation; cross symbol (×), inhibition.</p>
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29 pages, 1342 KiB  
Article
Malnutrition Risk in Older Adults: Evaluating the Diagnostic Relevance of Serum Biomarkers: SIRT-1, CCK-8, Melatonin, and Total Antioxidant Capacity (TAC)
by Karolina Kujawowicz, Iwona Mirończuk-Chodakowska, Monika Cyuńczyk and Anna Maria Witkowska
Nutrients 2025, 17(4), 726; https://doi.org/10.3390/nu17040726 - 18 Feb 2025
Viewed by 342
Abstract
Background/Objectives: Addressing the risk of malnutrition at an early stage is crucial to preventing its development, which can have a detrimental impact on physical and mental health status. This study investigates the potential role of biochemical biomarkers such as sirtuin 1 (SIRT-1), melatonin, [...] Read more.
Background/Objectives: Addressing the risk of malnutrition at an early stage is crucial to preventing its development, which can have a detrimental impact on physical and mental health status. This study investigates the potential role of biochemical biomarkers such as sirtuin 1 (SIRT-1), melatonin, cholecystokinin-8 (CCK-8), and total antioxidant capacity (TAC) in identifying the risk of malnutrition. Methods: This cross-sectional study assessed malnutrition risk in 153 community-dwelling older adults using the Mini Nutritional Assessment (MNA). Serum levels of SIRT-1, melatonin, and CCK-8 were analyzed with enzyme-linked immunosorbent assay (ELISA), and total antioxidant capacity (TAC) was measured using the ferric reducing ability of plasma (FRAP) method. Results: Serum levels of TAC and CCK-8 were significantly positively correlated with grip strength and visceral adipose tissue, with TAC levels also showing associations with appendicular skeletal muscle mass index (ASMI), total body water, total energy expenditure, fat-free mass index, and fat mass index (p < 0.001). CCK-8 emerged as a strong predictor of malnutrition risk (AUC = 0.58 in females, AUC = 0.64 in males), whereas SIRT-1 (AUC = 0.57 for both sexes), melatonin (AUC = 0.46 for females, AUC = 0.51 for males), and TAC (AUC = 0.42 for females, AUC = 0.54 for males) exhibited weaker predictive abilities. A multivariate model incorporating CCK-8 demonstrated excellent predictive accuracy (AUC = 0.84, 95% CI: 0.77–0.90) and indicated a potential association between elevated CCK-8 levels and a higher risk of malnutrition. Conclusions: In conclusion, this study highlights the effectiveness of a multi-parameter model incorporating CCK-8 as a reliable approach for assessing malnutrition risk in older adults, offering a comprehensive evaluation of the condition. However, further research is needed to confirm its applicability and accuracy in diverse elderly populations and clinical settings. Full article
(This article belongs to the Special Issue Nutritional Risk in Older Adults in Different Healthcare Settings)
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<p>Hypothetical model, based on a literature review, illustrating potential associations of SIRT-1, melatonin, CCK-8, and FRAP with malnutrition in older adults. Notes: CCK-8—cholecystokinin-8; Trp—tryptophan; Zn<sup>2+</sup>—zinc; A—vitamin A; Se—selenium; C—vitamin C; E—vitamin E; MT—melatonin; G—G-protein; MT1—melatonin receptor 1; MT2—melatonin receptor 2; Ac—activation; Nrf2—nuclear factor erythroid 2-related factor 2; FOXO3—forkhead box O3; MnSOD—Manganese superoxide dismutase; ROS—reactive oxygen species; FRAP—fluorescence recovery after photobleaching; SIRT-1—sirtuin 1; GPx—glutathione peroxidase; HO-1—haemoxygenase-1; OS—oxidative stress; AMPK—AMP-activated protein kinase; PGC-1α—peroxisome proliferator-activated receptor-gamma coactivator; NADPH+—nicotinamide adenine dinucleotide phosphate; NAD+—nicotinamide adenine nucleotide; Deac—deacetylation. Green upwards arrows indicate increase and red downwards arrows indicate decrease.</p>
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<p>ROC curve for predicting risk of malnutrition in older adults.</p>
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22 pages, 2878 KiB  
Article
Protective Role and Enhanced Intracellular Uptake of Curcumin in Retinal Cells Using Self-Emulsifying Drug Delivery Systems (SNEDDS)
by Elide Zingale, Sebastiano Masuzzo, Tatu Lajunen, Mika Reinisalo, Jarkko Rautio, Valeria Consoli, Agata Grazia D’Amico, Luca Vanella and Rosario Pignatello
Pharmaceuticals 2025, 18(2), 265; https://doi.org/10.3390/ph18020265 - 17 Feb 2025
Viewed by 411
Abstract
Background: Sirtuin-1 (SIRT1), a histone deacetylase enzyme expressed in ocular tissues with intracellular localization, plays a critical protective role against various degenerative ocular diseases. The link between reduced SIRT1 levels and diabetic retinopathy (DR) has prompted the exploration of natural therapeutic compounds that [...] Read more.
Background: Sirtuin-1 (SIRT1), a histone deacetylase enzyme expressed in ocular tissues with intracellular localization, plays a critical protective role against various degenerative ocular diseases. The link between reduced SIRT1 levels and diabetic retinopathy (DR) has prompted the exploration of natural therapeutic compounds that act as SIRT1 agonists. Curcumin (CUR), which has been shown to upregulate SIRT1 expression, is one such promising compound. However, effective delivery of CUR to the deeper ocular tissues, particularly the retina, remains a challenge due to its poor solubility and limited ocular penetration following topical administration. Within this context, the development of self-nanoemulsifying drug delivery systems (SNEDDS) for CUR topical ocular delivery represents a novel approach. Methods: In accordance with our prior research, optimized SNEDDS loaded with CUR were developed and characterized post-reconstitution with simulated tear fluid (STF) at a 1:10 ratio, showing suitable physicochemical and technological parameters for ocular delivery. Results: An entrapment efficiency (EE%) of approximately 99% and an absence of drug precipitation were noticed upon resuspension with STF. CUR-SNEDDS resulted in a better stability and release profile than free CUR under simulated ocular conditions. In vitro analysis of mucoadhesive properties revealed that CUR-SNEDDS, modified with a cationic lipid, demonstrated enhanced interactions with mucin, indicating the potential for improved ocular retention. Cytotoxicity tests demonstrated that CUR-SNEDDS did not affect the viability of human corneal epithelial (HCE) cells up to concentrations of 3 μM and displayed superior antioxidant activity compared to free CUR in an oxidative stress model using retinal pigment epithelial (ARPE-19) cells exposed to hydroquinone (HQ). Cell uptake studies confirmed an enhanced accumulation of CUR within the retinal cells following exposure to CUR-SNEDDS compared to neat CUR. CUR-SNEDDS, at lower concentrations, were found to effectively induce SIRT1 expression. Conclusions: The cytocompatibility, antioxidant properties, and enhanced cellular uptake suggest that these developed systems hold promise as formulations for the delivery of CUR to the retina. Full article
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<p>Solubility (mg/mL) of CUR in different vehicles (oils and surfactants).</p>
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<p>(<b>A</b>) Macroscopic visualization of AC and AC after reconstitution 1:10 in STF and (<b>B</b>) microscopic morphological analysis of AC after reconstitution (1:100,000 with PBS) by Zeta view analysis.</p>
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<p>Mucoadhesion strength of A+ in contact with mucin dispersion in terms of (<b>A</b>) absorbance and (<b>B</b>) zeta potential. Each bar represents the mean value ±SD; <span class="html-italic">n</span> = 3. Statistical analysis was performed by 2-way ANOVA (**** <span class="html-italic">p</span> &lt; 0.0001 vs. A+ at different time points).</p>
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<p>In vitro CUR release from CUR-SNEDDS (AC) compared to free CUR investigated for 48 h.</p>
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<p>Stability investigation of native CUR(C) in PBS and CURC-loaded SNEDDS (AC) at different conditions of exposition: 4 °C, 25 °C light and dark, and 40 °C. (Statistical analysis was made with Tukey’s multiple comparisons test **** <span class="html-italic">p</span> &lt; 0.0001 vs. C at different exposition conditions).</p>
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<p>Evaluation of cytotoxicity of CUR-SNEDDS loaded with different concentrations of CUR (0.1–5 μM), respectively, on the (<b>A</b>) HCE and (<b>B</b>) ARPE-19 cell lines (**** <span class="html-italic">p</span> &lt; 0.0001 vs. control, *** <span class="html-italic">p</span> &lt; 0.0005 vs. control).</p>
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<p>The (<b>A</b>) internalization and uptake of CUR (central column): 0.1 µM; 0.5 µM; 1 µM; 2 µM and CUR-loaded SNEDDS (right column): AC 0.1 µM; AC 0.5 µM; AC 1 µM; AC 2 µM into ARPE-19. White arrows point out CUR nanocarriers poutside cells. (<b>B</b>) Quantitative evaluation of recovered CUR in medium and not internalized after uptake test (**** <span class="html-italic">p</span> &lt; 0.0001 vs. C). (<b>C</b>) Assessment of SIRT1 protein expression levels following AC treatment for 24 h at selected concentrations of 0.1 and 0.5 µM (** <span class="html-italic">p</span> &lt; 0.005 vs. CTRL).</p>
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<p>Evaluation of HQ (600 μM) effect on ARPE-19 cell viability and recovery with co-treatment of HQ and SNEDDS loaded with different concentrations of CUR (0.1–2 μM) (**** <span class="html-italic">p</span> &lt; 0.0001 vs. HQ; *** <span class="html-italic">p</span> &lt; 0.0005 vs. HQ).</p>
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21 pages, 2160 KiB  
Article
Phenolic Compounds from Haskap Berries Have Structure, Combination, and Cell Line-Dependent Impacts on the Longevity-Associated Deacetylase Sirtuin 1
by Morgan A. Fleming, Nicholas H. Low and Christopher H. Eskiw
Cells 2025, 14(4), 295; https://doi.org/10.3390/cells14040295 - 17 Feb 2025
Viewed by 236
Abstract
It is well established that phenolic compounds from plant sources impact readouts of cell health such as reduced radical and reactive oxygen species. However, it is unclear if specific phenolic structures impact other cellular processes or proteins, such as the evolutionary conserved deacetylase [...] Read more.
It is well established that phenolic compounds from plant sources impact readouts of cell health such as reduced radical and reactive oxygen species. However, it is unclear if specific phenolic structures impact other cellular processes or proteins, such as the evolutionary conserved deacetylase Sirtuin 1 (SIRT1), and if phenolic combinations interact synergistically to do so. We observed that structurally diverse haskap berry phenolics (caffeic acid, cyanidin, kaempferol-3-O-glucoside, and gentisic acid) differentially impacted normal primary human fibroblast growth, which has been linked to SIRT1. These results were consistent with previous work from our lab indicating that haskap phenolic extracts/fractions impact human cell growth via SIRT1-dependent mechanisms. Therefore, we furthered the investigation into SIRT1 and phenolic structure and observed that the individual phenolics or their combinations had no observable impact on SIRT1 transcript abundance or cellular localization. We also observed that select phenolics decreased SIRT1 protein abundance and increased SIRT1 activity. The catechol-containing phenolics outperformed those that lack a catechol group, indicating potential structure-dependent impact(s). Potential synergy between the specific phenolics analyzed was observed in Western blot, and potential antagonism was identified in the SIRT1 activity assay. Results were concomitant with the presence of different phenolic structures, phenolic combinations, and cell type (sex and/or individual differences). These results highlight the possible significance of the catechol structure and indicate that phenolics have the potential to impact cell processes, which the authors hypothesize to be due to mechanisms that are independent of antioxidant activity. Full article
(This article belongs to the Section Cellular Aging)
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<p>Haskap berries and the structures of the four phenolics selected for this work. The phenolics were supplemented to normal primary human fibroblasts individually to determine their function(s) and in equimolar combinations to examine synergy.</p>
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<p>The phenolic treatments have structure-dependent impacts on 2DD and 07124B cell growth behavior. (<b>A</b>) Representative images of DMSO and CY-treated 2DD cells following a 72 h treatment period. Scale bar = 100 μm. (<b>B</b>) Quantified PDT assay results. Following the treatment period, cells were collected and counted affording the calculation of PDT that was normalized to the vehicle control (DMSO). Error bars represent the standard error of the mean (<span class="html-italic">n</span> = 3; <span class="html-italic">p</span> = * <span class="html-italic">p</span> &lt; 0.1, ** <span class="html-italic">p</span> &lt; 0.05, *** <span class="html-italic">p</span> &lt; 0.01). (<b>C</b>) Cell viability assay results, the phenolic treatments maintained high levels of cell viability indicating that these compounds did not increase 2DD or 07124B cell death. Error bars represent the standard error of the mean (<span class="html-italic">n</span> = 3). Treatment abbreviations are as follows: vehicle control (DMSO), caffeic acid (CA), cyanidin (CY), kaempferol-3-<span class="html-italic">O</span>-glucoside (K3G), and gentisic acid (GA).</p>
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<p>The phenolic treatments had no significant impact on <span class="html-italic">SIRT1</span> transcript abundance but had structure-, interaction-, and/or concentration-dependent impacts on SIRT1 protein abundance. (<b>A</b>) Cells were treated followed by RNA extraction, cDNA synthesis, and RT-qPCR, a fold change of ±2 was considered significant. (<b>B</b>) Impacts of the phenolic treatments on SIRT1 protein abundance. Cells were treated followed by whole cell lysis, harvesting, and Western blot (<span class="html-italic">n</span> = 3), representative Western blot and quantified densitometry results are presented. Coomassie blue gels were used as a load control. (<b>C</b>) Impacts of the phenolic treatments on SIRT1 protein abundance in response to H<sub>2</sub>O<sub>2</sub> (<span class="html-italic">n</span> = 3; <span class="html-italic">p</span> = * <span class="html-italic">p</span> &lt; 0.1, ** <span class="html-italic">p</span> &lt; 0.05, *** <span class="html-italic">p</span> &lt; 0.01). Abbreviations are as follows: vehicle control (DMSO), caffeic acid (CA), cyanidin (CY), kaempferol-3-<span class="html-italic">O</span>-glucoside (K3G), gentisic acid (GA), molecular weight (MW), and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>).</p>
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<p>The phenolic treatments had no observable impact on SIRT1 localization but had structure and cell line-dependent impacts on SIRT1 activity level. (<b>A</b>) Representative immunofluorescence images. Chromatin was counter-stained with DAPI and is represented by the blue color, SIRT1 is represented by the red color. Greyscale images were false colored in Photoshop and all treatments were imaged with consistent exposure times and treated equally in Photoshop to avoid artifact creation. The DAPI (blue) and SIRT1 (red) images were overlayed to create the Merge image, where a purple color suggests co-localization of chromatin and SIRT1. A total of 30–50 cells were imaged per treatment replicate (<span class="html-italic">n</span> = 2). (<b>B</b>) SIRT1 activity assay results. Cells were treated with the selected phenolics prior to harvesting in non-denaturing lysis buffer. Error bars represent the standard error of the mean and fluorescence values were normalized to DMSO (<span class="html-italic">n</span> = 2; <span class="html-italic">p</span> = ** <span class="html-italic">p</span> &lt; 0.05, *** <span class="html-italic">p</span> &lt; 0.01). Treatment abbreviations are as follows: vehicle control (DMSO), caffeic acid (CA), cyanidin (CY), kaempferol-3-<span class="html-italic">O</span>-glucoside (K3G), gentisic acid (GA), and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>).</p>
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31 pages, 1588 KiB  
Review
The Potential of Superoxide Dismutase-Rich Tetraselmis chuii as a Promoter of Cellular Health
by Stuart P. Cocksedge, Lalia Mantecón, Enrique Castaño, Carlos Infante and Stephen J. Bailey
Int. J. Mol. Sci. 2025, 26(4), 1693; https://doi.org/10.3390/ijms26041693 - 16 Feb 2025
Viewed by 520
Abstract
Tetraselmis chuii (T. chuii) is a green, marine, eukaryotic, microalgae that was authorized in the European Union (EU) as a novel food for human consumption in 2014, and as a food supplement in 2017. This narrative review will provide an overview [...] Read more.
Tetraselmis chuii (T. chuii) is a green, marine, eukaryotic, microalgae that was authorized in the European Union (EU) as a novel food for human consumption in 2014, and as a food supplement in 2017. This narrative review will provide an overview of preclinical and clinical trials assessing the efficacy of a T. chuii-derived ingredient, characterized by a high superoxide dismutase (SOD) activity (SOD-rich T. chuii), to improve various aspects of cellular health. Collectively, results from in vitro, and more importantly in vivo research, support SOD-rich T. chuii as a potential promoter of cellular health. Principally, the ingredient appears to function as an indirect antioxidant by boosting intracellular antioxidant systems. Moreover, it can positively modulate inflammatory status by up-regulating anti-inflammatory and down-regulating pro-inflammatory cytokines and factors. In addition, SOD-rich T. chuii appears to promote cellular health though protecting from DNA damage, boosting immune function, strengthening cell structure and integrity, and positively modulating cell signaling pathways. There is also some evidence to suggest that SOD-rich T. chuii may improve aspects of mitochondrial function through the up-regulation of genes linked to mitochondrial biogenesis and ATP synthesis. From the trials conducted to date, transcriptional activation of nuclear factor erythroid 2-related factor 2 (NRF2) and sirtuin 1 (SIRT1) appear to be important in mediating the effects of SOD-rich T. chuii on cellular health. These exciting preliminary observations suggest that SOD-rich T. chuii may represent a natural blue food supplement with the potential to enhance various aspects of cellular health. Full article
(This article belongs to the Special Issue Molecular Mechanisms of Bioactive Nutrients Promoting Human Health)
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<p>The effects of SOD-rich <span class="html-italic">T. chuii</span> on promoting cellular health.</p>
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14 pages, 1859 KiB  
Article
Focal Adhesion Kinase Alleviates Simulated Microgravity-Induced Inhibition of Osteoblast Differentiation by Activating Transcriptional Wnt/β-Catenin-BMP2-COL1 and Metabolic SIRT1-PGC-1α-CPT1A Pathways
by Yiling Bai, Zhaojia Wu, Scot C. Leary, Chen Fang, Michelle Yu, Harald Genth, Yufeng Xie, Jinhui Shi and Jim Xiang
Int. J. Mol. Sci. 2025, 26(4), 1669; https://doi.org/10.3390/ijms26041669 - 15 Feb 2025
Viewed by 467
Abstract
The metabolic poise, or balance, between glycolysis and fatty acid oxidation (FAO) has recently been found to play a critical role in osteogenic differentiation and homeostasis. While simulated microgravity (SMG) is known to impede osteoblast differentiation (OBD) by inhibiting the Wnt/β-catenin pathway, how [...] Read more.
The metabolic poise, or balance, between glycolysis and fatty acid oxidation (FAO) has recently been found to play a critical role in osteogenic differentiation and homeostasis. While simulated microgravity (SMG) is known to impede osteoblast differentiation (OBD) by inhibiting the Wnt/β-catenin pathway, how it affects osteoblast metabolism in this context remains unclear. We previously analyzed the effect of SMG on the differentiation of pre-osteoblast MC3T3-E1 cells and found that it reduced focal adhesion kinase (FAK) activity. This, in turn, downregulated Wnt/β-catenin and two of its downstream targets critical for OBD bone morphogenic protein-2 (BMP2) and type-1 collagen (COL1) formation, leading to a reduction in alkaline phosphatase (ALP) activity and cell matrix mineralization. In this study, we further analyzed how SMG-induced alterations in energy metabolism contribute to the inhibition of OBD in MC3T3-E1 cells. Consistent with our earlier findings, we demonstrated that SMG inhibits OBD by downregulating the collective activity of FAK and the Wnt/β-catenin-BMP2-COL1 transcriptional pathway. Interestingly, we observed that SMG also reduces the abundance of sirtuin-1 (SIRT1), peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and carnitine palmitoyl transferase-1α (CPT1A), which are all key metabolic factors regulating mitochondrial number and FAO capacity. Accordingly, we found that the mitochondrial content and FAO potential of MC3T3-E1 cells were lower upon exposure to SMG but were both rescued upon administration of the FAK activator cytotoxic necrotizing factor-1 (CNF1), thereby allowing cells to overcome SMG-induced inhibition of OBD. Taken together, our study indicates that the metabolic regulator SIRT1 may be a new target for reversing SMG-induced bone loss. Full article
(This article belongs to the Special Issue 25th Anniversary of IJMS: Advances in Biochemistry)
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<p>SMG alters the cytoskeleton and inhibits FAs. Cells cultured under 1 g, SMG or SMG + CNF1 conditions were imaged (<b>A</b>) by light microscopy to show morphology and (<b>B</b>) by fluorescence microscopy to show FITC-vinculin-positive (green) FA spots (white arrows). Cells were also counterstained with DAPI (blue) to visualize nuclei. The histogram bars represent the average number of FA spots detected using ImageJ software (v1.45) from three random regions under a 40× objective lens magnification field. Scale bar: 50 μm. Data from three independent experiments are presented as the mean ± SD. Significance analysis of the experimental data for each group was performed using Student’s <span class="html-italic">t</span> test (** <span class="html-italic">p</span> &lt; 0.01).</p>
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<p>SMG attenuates OBD by inhibiting the Wnt/β-catenin signaling pathway. Western blot analysis of the steady-state levels of pFAK (Y397), COL1, β-catenin, ALP and BMP2 in MC3T3-E1 cells cultured under 1 g, SMG or SMG + CNF1 conditions. The histogram bars represent protein abundance normalized to the β-actin control and expressed relative to MC3T3-E1 cells cultured under the 1 g condition. Data from three independent experiments are presented as the mean ± SD. Significance analysis of the experimental data for each group was performed using Student’s <span class="html-italic">t</span> test (* <span class="html-italic">p</span> &lt; 0.05; ** <span class="html-italic">p</span> &lt; 0.01).</p>
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<p>SMG inhibits OBD and mineralization. (<b>A</b>) MC3T3-E1 cells cultured under 1 g, SMG or SMG + CNF1 conditions were stained with ALP and analyzed by flow cytometry to quantify its abundance. The histogram bars represent the mean fluorescence intensity (MFI) for each group relative to MC3T3-E1 cells cultured under the 1 g condition. (<b>B</b>) Analysis of ALP activity in MC3T3-E1 cells cultured under SMG and SMG + CNF1 conditions compared to 1 g. (<b>C</b>) Representative images of MC3T3-E1 cells stained with Alizarin Red after 14 d of culture to depict OBD. The calcified nodules per 20× field were quantified using ImageJ software. Scale bar: 500 μm or 100 μm. For all panels, data from three independent experiments are presented as the mean ± SD. Significance analysis of the experimental data for each group was performed using Student’s <span class="html-italic">t</span> test (* <span class="html-italic">p</span> &lt; 0.05).</p>
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<p>SMG impairs mitochondrial biogenesis by inhibiting the SIRT1-PGC-1α-CPT1A signaling pathway. (<b>A</b>) Western blot analysis of SIRT1, PGC-1α, AQP9 and CPT1A abundance in MC3T3-E1 cells cultured under 1 g, SMG or SMG + CNF1 conditions. The histogram bars represent protein abundance normalized to the β-actin control and expressed relative to MC3T3-E1 cells cultured under the 1 g condition. (<b>B</b>) MC3T3-E1 cells cultured under 1 g, SMG or SMG + CNF1 conditions were stained with the mitochondria-specific dye MitoTracker Green FM and analyzed by flow cytometry to quantify organelle mass. The histogram bars represent the mean fluorescence intensity (MFI) for each group relative to MC3T3-E1 cells cultured under the 1 g condition. (<b>C</b>) Representative confocal images of MitoTracker green-labeled mitochondria to show organelle content in MC3T3-E1 cells cultured under 1 g, SMG or SMG + CNF1 conditions. Cells were also stained with Hoechst solution to label nuclei in blue. For panels (<b>A</b>,<b>B</b>), data from three independent experiments are presented as the mean ± SD. Significance analysis of the experimental data for each group was performed using Student’s <span class="html-italic">t</span> test (* <span class="html-italic">p</span> &lt; 0.05; ** <span class="html-italic">p</span> &lt; 0.01).</p>
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<p>SMG reduces FAO metabolism. Bar graphs of the ECAR and OCR/ECAR ratio as well as the OCR measured in real time and in response to the indicated mitochondrial inhibitors in MC3T3-E1 cells cultured under 1 g, SMG or SMG + CNF1 conditions. Vertical dotted lines indicate the time when a total of 1.5 µM oligomycin, 2.5 µM FCCP, and 0.5 µM rotenone and antimycin-A were sequentially added to the wells. Data from three independent experiments are presented as the mean ± SD. Significance analysis of the experimental data for each group was performed using Student’s <span class="html-italic">t</span> test (* <span class="html-italic">p</span> &lt; 0.05; ** <span class="html-italic">p</span> &lt; 0.01).</p>
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<p>SMG modulates OBD by regulating the activity of both transcriptional and metabolic pathways. Schematic diagram showing that SMG inhibits FAK and downregulates FAK-regulated signaling pathways, thereby leading to the inhibition of OBD. These FAK-regulated signaling pathways include the transcriptional Wnt/β-catenin-BMP2-COL1 pathway for OBD and the metabolic SIRT1-PGC-1α-CPT1A pathway responsible for generating adequate ATP from FAO. The FAK activator CNF1 reverts the suppressive effects of SMG via the activation of the transcriptional Wnt/β-catenin-BMP2-COL1 pathway and the metabolic SIRT1-PGC-1α-CPT1A pathway. In this figure, red arrows represent upregulation and blue arrows denote downregulation.</p>
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27 pages, 2769 KiB  
Review
Autophagy in High-Fat Diet and Streptozotocin-Induced Metabolic Cardiomyopathy: Mechanisms and Therapeutic Implications
by Rong Zhou, Zutong Zhang, Xinjie Li, Qinchun Duan, Yuanlin Miao, Tingting Zhang, Mofei Wang, Jiali Li, Wei Zhang, Liyang Wang, Odell D. Jones, Mengmeng Xu, Yingli Liu and Xuehong Xu
Int. J. Mol. Sci. 2025, 26(4), 1668; https://doi.org/10.3390/ijms26041668 - 15 Feb 2025
Viewed by 611
Abstract
Metabolic cardiomyopathy, encompassing diabetic and obese cardiomyopathy, is an escalating global health concern, driven by the rising prevalence of metabolic disorders such as insulin resistance, type 1 and type 2 diabetes, and obesity. These conditions induce structural and functional alterations in the heart, [...] Read more.
Metabolic cardiomyopathy, encompassing diabetic and obese cardiomyopathy, is an escalating global health concern, driven by the rising prevalence of metabolic disorders such as insulin resistance, type 1 and type 2 diabetes, and obesity. These conditions induce structural and functional alterations in the heart, including left ventricular dysfunction, fibrosis, and ultimately heart failure, particularly in the presence of coronary artery disease or hypertension. Autophagy, a critical cellular process for maintaining cardiac homeostasis, is frequently disrupted in metabolic cardiomyopathy. This review explores the role of autophagy in the pathogenesis of high-fat diet (HFD) and streptozotocin (STZ)-induced metabolic cardiomyopathy, focusing on non-selective and selective autophagy pathways, including mitophagy, ER-phagy, and ferritinophagy. Key proteins and genes such as PINK1, Parkin, ULK1, AMPK, mTOR, ATG7, ATG5, Beclin-1, and miR-34a are central to the regulation of autophagy in metabolic cardiomyopathy. Dysregulated autophagic flux impairs mitochondrial function, promotes oxidative stress, and drives fibrosis in the heart. Additionally, selective autophagy processes such as lipophagy, regulated by PNPLA8, and ferritinophagy, modulated by NCOA4, play pivotal roles in lipid metabolism and iron homeostasis. Emerging therapeutic strategies targeting autophagy, including plant extracts (e.g., curcumin, dihydromyricetin), endogenous compounds (e.g., sirtuin 3, LC3), and lipid/glucose-lowering drugs, offer promising avenues for mitigating the effects of metabolic cardiomyopathy. Despite recent advances, the precise mechanisms underlying autophagy in this context remain poorly understood. A deeper understanding of autophagy’s regulatory networks, particularly involving these critical genes and proteins, may lead to novel therapeutic approaches for treating metabolic cardiomyopathy. Full article
(This article belongs to the Special Issue Cellular and Molecular Mechanisms of Myocardial Diseases)
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<p>A comprehensive scheme for the complex regulation of cardiac non-selective autophagy in HFD-induced metabolic cardiomyopathy. LT-HFD (long-term high-fat diet) consumption not only activates the mTOR signaling pathway but also suppresses the AMPK signaling pathway in the heart, which impairs the initiation of phagophore nucleation. Vesicle expansion and autophagosome formation guided by ATG5-ATG12 and ATG7-LC3 was inhibited in HFD-induced metabolic cardiomyopathy. Metabolism-related enzymes included aldehyde dehydrogenase (ALDH2) and NADPH oxidase 2 (Nox2) are involved in the regulation of autophagy in metabolic cardiomyopathy. Short-term high-fat diet (ST-HFD) consumption prior to I/R promoted autophagy by the NF-kB-dependent signaling pathway. Otherwise, autophagy was activated by ST-HFD consumption in mouse hearts by inactivation of Mst1. Solid lines represent proven mechanisms, dotted lines represent unknown mechanisms. Targeted agents enclosed in yellow oval boxes are connected to therapeutic targets by blue lines. Red dots indicate LC3 II. The rest of diverse color dots indicates non-selective components involved. (↓: stimulatory modification, ⫰: inhibitory modification). (Not to scale).</p>
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<p>A comprehensive scheme for the complex regulation of cardiac non-selective autophagy in STZ-induced metabolic cardiomyopathy. Various studies have indicated that autophagy plays both protective and pathogenic roles in the development of STZ-induced metabolic cardiomyopathy. The pathways involved in the downregulation of autophagy STZ-induced metabolic cardiomyopathy are the LKB1/AMPK/ULK1 signaling pathway, the PI3K/AKT/mTOR signaling pathway, the axis of CREG1-FBXO27-LAMP2, and the AKT/GSK3β signaling pathway. Mst1 suppresses autophagy by increasing interaction between Beclin1 and BCL2. FOXO1 (forkhead box protein O1) induced excessive autophagy in STZ-induced metabolic cardiomyopathy. The RIPK1/RIPK3 signaling pathway and FOXO1 was involved in excessive autophagic flux in the heart, which was induced by STZ. Hyperactivation of miR-34a promotes autophagy in STZ-induced metabolic cardiomyopathy. Solid lines represent proven mechanisms, dotted-line arrows represent unknown mechanisms. Targeted agents enclosed in yellow oval boxes are connected to therapeutic targets by blue lines. Red dots indicate LC3 II. The rest of diverse color dots indicates non-selective components involved. (↓: stimulatory modification, ⫰: inhibitory modification). (Not to scale).</p>
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<p>A simplified scheme for the regulation of cardiac selective autophagy in HFD-induced metabolic cardiomyopathy. ER-phagy, mitophagy, and ferritinophagy are implicated in the development HFD-induced metabolic cardiomyopathy. The PINK1/Parkin ubiquitin-mediated mitophagy pathway, which involves factors such as H19, ACC2, BRD4, SQSTM1, Nampt, and SERP2, is inhibited, and the alternative Ulk1-Rab9-dependent mitophagy pathway is activated. Panels a and b, respectively, are cited from [<a href="#B37-ijms-26-01668" class="html-bibr">37</a>,<a href="#B109-ijms-26-01668" class="html-bibr">109</a>], and depict the changes in autophagy regulated by the ULK/Rab9 and Atg7/LC3 pathways during the HFD intervention. ER stress, as evidenced by a significant increase in the protein levels of PERK, IRE1α, ATF6α and CHOP, was activated in the diabetic rat heart. Although the effect has not been demonstrated in rodent models, HG treatment has been shown to enhance ER-phagy (upregulation of Sec62 and RTN3 and downregulation of FAM134B) in H9c2 cells. This finding is corroborated by the upregulation of Sec62 and RTN3, as well as the downregulation of FAM134B. HFD significantly increases ferritinophagy by activating the STAT3/NCOA4/FTH1 axis, which promotes ferroptosis due to iron overload. Solid lines represent proven mechanisms, dotted lines represent unknown mechanisms. Targeted agents enclosed in yellow oval boxes are connected to therapeutic targets by blue lines. (↓: stimulatory modification, ⫰: inhibitory modification).</p>
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<p>Mechanistic insights and multifaceted applications of autophagy as a potential therapeutic target for metabolic cardiomyopathies. This illustration depicts the intricate autophagy relationship, and operates through diverse pathways separately associated with non-selective and selective autophagy. Autophagy mechanisms ameliorate the positive effects of fasting and exercise on metabolic cardiomyopathy in humans. Solid lines represent confirmed mechanisms, while dotted lines represent possible mechanisms. Blue arrows are physiological paths; Dark green single-head arrows, selective and non-selective autophagy, metabolic cardiomyopathy; Light green double-head arrows, interference improvement of metabolic cardiomyopathy; Light green single-head arrows, non-selective autophagy fed back to improvement of metabolic cardiomyopathy.</p>
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33 pages, 10543 KiB  
Article
Withania somnifera Ameliorates Doxorubicin-Induced Nephrotoxicity and Potentiates Its Therapeutic Efficacy Targeting SIRT1/Nrf2, Oxidative Stress, Inflammation, and Apoptosis
by Amany Mohammed Mohmmed Hegab, Soha Osama Hassanin, Reham Hassan Mekky, Samah Sulaiman Abuzahrah, Alaaeldin Ahmed Hamza, Iman M. Talaat and Amr Amin
Pharmaceuticals 2025, 18(2), 248; https://doi.org/10.3390/ph18020248 - 12 Feb 2025
Viewed by 630
Abstract
Background: Doxorubicin (DOX) is a very powerful chemotherapy drug. However, its severe toxicity and potential for resistance development limit its application. Withania somnifera L. Dunal (WIT) has therapeutic capacities, including anti-inflammatory, antioxidant, and anticancer activities. This study investigates the preventative benefits of [...] Read more.
Background: Doxorubicin (DOX) is a very powerful chemotherapy drug. However, its severe toxicity and potential for resistance development limit its application. Withania somnifera L. Dunal (WIT) has therapeutic capacities, including anti-inflammatory, antioxidant, and anticancer activities. This study investigates the preventative benefits of a standardized WIT extract against DOX-induced renal damage in vivo. We also investigate the synergistic effects of combining WIT and DOX to improve therapeutic efficacy in breast cancer cells (MCF7-ADR). Methods: This study employed an animal model where rats were administered 300 mg/kg/day of WIT orally for a duration of 14 days. Rats received DOX injections at a dose of 5 mg/kg, for a total of 15 mg, on the 6th, 8th, and 10th days. Results: Present results revealed that WIT reduced DOX-induced increase levels of blood urea and creatinine and the activity of kidney injury molecule-1. WIT also reduced renal tissue damage, oxidative stress, and levels of pro-inflammatory markers. WIT alleviated the effects of DOX on nuclear factor erythroid 2-related factor 2, heme oxygenase-1, and sirtuin 1 in the renal tissues. WIT modulated nuclear factor-κB activity and decreased apoptotic indicators. Furthermore, WIT improves DOX’s capacity to kill drug-resistant MCF7-ADR cells by arresting the cell cycle and promoting apoptosis. Chemical analysis of WIT root extract revealed 34 distinct compounds, including alkaloids, withanolides, flavanones, and fatty acids. Conclusions: These constituents synergistically contribute to WIT’s antioxidant, anti-inflammatory, and anti-apoptotic properties. In addition, they confirm its ability to reduce systemic toxicity while improving treatment efficacy. Full article
(This article belongs to the Section Pharmacology)
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<p>(<b>a</b>) The base peak chromatograms (BPCs) of the extract from the roots of WIT in the positive ionization mode. (<b>b</b>) A bubble plot shows the observed masses (<span class="html-italic">m</span>/<span class="html-italic">z</span>) plotted against the retention time (RT), indicating the phytochemical classes and their corresponding relative abundance. (<b>c</b>) The structures of the principal metabolites.</p>
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<p>The impact of WIT on the concentrations of urea (<b>A</b>), creatinine (<b>B</b>), albumin (<b>D</b>), and renal level of KIM-1 (<b>C</b>) in rats with DOX-induced nephrotoxicity. The results are expressed as the mean ± SEM (n = 6). The significance was assessed using one-way analysis of variance (ANOVA) followed by Tukey’s post hoc test; <sup>a</sup> (<span class="html-italic">p</span> &lt; 0.05) is statistically significant in comparison to the control group, whereas <sup>b</sup> (<span class="html-italic">p</span> &lt; 0.05) is statistically significant relative to the DOX group.</p>
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<p>The protective effect of WIT in mitigating kidney damage caused by DOX. The panels display histological alterations in kidney tissue for different groups, seen using H&amp;E staining at a magnification of 200× and 400×. The kidney sections from the WIT group and the control group’s light micrographs display the normal structure of the renal glomerulus corpuscle (G), proximal (P) and distal tubules (D), and blood vessels (V). On the other hand, kidney sections from the DOX groups showed pathological characteristics such as atrophy or distortion of the glomerular capsule (black arrow), widening and degeneration of the tubules (yellow arrow), focal inflammatory cell infiltration between degenerated tubules (white arrow), congestion in blood vessels and focal hemorrhages between tubules (red arrow), and perivascular edema and fibrosis (thick arrow). Kidney section from DOX+WIT showing normal histological structure with mild histopathological changes such as atrophy or distortion of the glomerular capsule (black arrow), tubular dilatation and degenerations (yellow arrows), and congestion and diluted of blood vessels (red arrow).</p>
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<p>The impact of WIT on cell death (apoptosis) in rats with doxorubicin-induced kidney damage. (<b>A</b>) Representative photos depicting immunohistochemical staining with TUNEL-positive cells in kidney sections from all evaluated groups. (<b>B</b>) The TUNEL-positive cells in several experimental groups. TUNEL-positive cells were quantified in each segment by counting the number of cells with brown staining (arrows) in 10 areas at 400× magnification. (<b>C</b>) The impact of WIT on the renal levels of BAX and (<b>D</b>) Caspase-3 in rats with doxorubicin-induced nephrotoxicity. The results are expressed as the mean ± SEM (n = 6). The significance was assessed using one-way analysis of variance (ANOVA) followed by Tukey’s post hoc test; <sup>a</sup> (<span class="html-italic">p</span> &lt; 0.05) is statistically significant in comparison to the control group, whereas <sup>b</sup> (<span class="html-italic">p</span> &lt; 0.05) is statistically significant relative to the DOX group.</p>
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<p>(<b>A</b>–<b>G</b>) The impact of WIT on oxidative stress markers in the kidneys during DOX-induced nephrotoxicity. (<b>H</b>) The impact of WIT on calcium levels in the kidneys during DOX-induced nephrotoxicity. The results are expressed as the mean ± SEM (n = 6). The significance was assessed using one-way analysis of variance (ANOVA) followed by Tukey’s post hoc test; <sup>a</sup> (<span class="html-italic">p</span> &lt; 0.05) is statistically significant in comparison to the control group, whereas <sup>b</sup> (<span class="html-italic">p</span> &lt; 0.05) is statistically significant relative to the DOX group.</p>
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<p>Illustrates the impact of WIT on renal inflammatory markers in rats with DOX-induced nephrotoxicity. The indicators examined include NF-kB (<b>A</b>), TNF-α (<b>B</b>), IL-1β (<b>C</b>), and IL-6 (<b>D</b>). The results are expressed as the mean ± SEM (n = 6). The significance was assessed using one-way analysis of variance (ANOVA) followed by Tukey’s post hoc test; <sup>a</sup> (<span class="html-italic">p</span> &lt; 0.05) is statistically significant in comparison to the control group, whereas <sup>b</sup> (<span class="html-italic">p</span> &lt; 0.05) is statistically significant relative to the DOX group.</p>
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<p>The impact of WIT on the renal expression of Nrf2, HO-1, and SIRT1 in rats treated with DOX. The levels of Nrf2 (<b>A</b>), HO-1 (<b>B</b>), and SIRT1 (<b>C</b>) mRNA in the kidneys of various experimental groups were measured using qRT-PCR and compared to β-actin expression. The renal protein levels of Nrf2 (<b>D</b>) and SIRT1 (<b>E</b>) were measured using ELISA. The results are expressed as the mean ± SEM (n = 6). The significance was assessed using one-way analysis of variance (ANOVA) followed by Tukey’s post hoc test; <sup>a</sup> (<span class="html-italic">p</span> &lt; 0.05) is statistically significant in comparison to the control group, whereas <sup>b</sup> (<span class="html-italic">p</span> &lt; 0.05) is statistically significant relative to the DOX group.</p>
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<p>Effects of DOX and WIT on the viability of MCF-7, MCF-7/ADR, and MCF-10A cells. (<b>A</b>) MTT experiment demonstrating the effect of DOX on cell viability of MCF-7, MCF-7/ADR, and MCF-10A at various doses 24 h after treatment. (<b>B</b>) DOX IC<sub>50</sub> on MCF-7, MCF-7/ADR, and MCF-10A cells. (<b>C</b>) An MTT experiment demonstrated WIT’s cytotoxicity on MCF-7, MCF-7/ADR, and MCF-10A cells after 24 h of treatment. (<b>D</b>) The WIT IC<sub>50</sub> is on MCF-7, MCF-7/ADR, and MCF-10A cells. (<b>E</b>) The combination index (CI) values for DOX and WIT in MCF-7/ADR cells were calculated using CompuSyn software (version 1.25). (<b>F</b>) The IC<sub>50</sub> of DOX and DOX-WIT on MCF-7/ADR cells after 24 h of treatment (<b>G</b>) The cell viability of DOX and DOX-WIT combination for MCF-7/ADR cells, with <sup>a</sup> <span class="html-italic">p</span> &lt; 0.05 vs. the DOX treated group. (<b>H</b>) CI values were computed using CompuSyn software based on G’s combination data.</p>
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<p>Effect of WIT and DOX combination on apoptosis and cell cycle distribution in MCF-7/ADR cells. (<b>A</b>) Flow cytometric study of cells stained with Annexin V and PI to assess apoptosis 24 h post-treatment with 20 μg/mL WIT, 6.2 μg/mL DOX, and combinations of 10 and 20 μg/mL WIT with 6.2 μg/mL DOX. The percentage of cells in each quadrant corresponds to a particular cell type: necrotic cells (Q1), live cells (Q3), early apoptotic cells (Q4), and late apoptotic cells (Q2). (<b>B</b>) Flow cytometric examination shows the distribution of cells in the G0/G1, S, and G2/M phases following treatment with DMSO (less than 1% as a negative control), WIT, DOX, and DOX+WIT at concentrations of 10 and 20 μg/mL. (<b>C</b>) Calculating the rates of apoptosis and necrosis with the calibration from (<b>A</b>). Values are expressed as a proportion of total cells. Each point shows the mean ± SEM (n = 3). (<b>D</b>) Calculating the percentage of cell dispersion across different cell cycle phases. Each bar represents the mean ± SEM of three independent studies. A two-way ANOVA and Tukey’s multiple comparison tests evaluated significant differences among experimental groups. Non-identical letters signify a statistically significant difference between experimental groups (<span class="html-italic">p</span> &lt; 0.05).</p>
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<p>Schematic diagram of the antioxidant, anti-inflammatory, and antiapoptotic effects of WIT against DOX-induced nephrotoxicity and the enhancement of the efficacy of DOX in treating breast cancer. CAT, catalase; BAX, Bcl-2–associated X protein; DOX, doxorubicin; GSH, reduced glutathione; HO1, haem oxygenase-1; IL-1β, interleukin-1 beta; IL-6, interleukin-6; KIM-1, kidney injury molecule-1; MPO, myeloperoxidase; erythroid-2-related factor 2; P. carbonyl, Portion carbonyl; SIRT-1, Sirtuin-1; SOD, superoxide dismutase; TAC, total antioxidant capacity; MDA, malondialdehyde; TNF-α, tumor necrosis factor-α; WIT, <span class="html-italic">Withania somnifera</span>.</p>
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29 pages, 9268 KiB  
Article
In Silico Characterization of Sirtuins in Acetic Acid Bacteria Reveals a Novel Phylogenetically Distinctive Group
by Igor Jugović and Janja Trček
Molecules 2025, 30(3), 635; https://doi.org/10.3390/molecules30030635 - 31 Jan 2025
Cited by 1 | Viewed by 731
Abstract
Acetic acid bacteria are single-celled organisms well-known for their ability to convert ethanol into acetic acid. Still, recent research suggests they may harbor another attractive characteristic—the production of proteins with remarkable similarities to sirtuins. Sirtuins have been linked to lifespan extension in various [...] Read more.
Acetic acid bacteria are single-celled organisms well-known for their ability to convert ethanol into acetic acid. Still, recent research suggests they may harbor another attractive characteristic—the production of proteins with remarkable similarities to sirtuins. Sirtuins have been linked to lifespan extension in various organisms, raising intriguing questions about the potential connection between acetic acid bacteria and the biology of aging. This article delves into the characterization of sirtuin homologs in acetic acid bacteria. Up to three types of sirtuin homologs have been identified in 21% of acetic acid bacteria genomes deposited in NCBI. All three types were present only in the genera Acetobacter and Novacetimonas, which are known to survive in the harshest environmental conditions (high concentrations of acetic acid and ethanol). Interestingly, two types of these sirtuin homologs (SirAAB-L and SirAAB-S) constitute a separate group (SirAAB), distinctive from all other presently known sirtuins. The results obtained in silico thus encourage further studies into the function of these types of sirtuins and their interplay with metabolic pathways in these industrially important bacteria. Full article
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Figure 1
<p>Unrooted phylogram illustrating the relationship between the known sirtuin classes (I–IV, U, and sirtuins associated with macrodomains (SirTM)). Sirtuins labeled from SIRT1 to SIRT7, Class U sirtuin, <span class="html-italic">Escherichia coli</span> sirtuin, and SirTM represent the reference sequences, which are surrounded by other sequences from various bacterial species. SIRT1-SIRT7 represent human sirtuins, Class U sirtuin is represented by <span class="html-italic">Geobacillus</span> sp. and the SirTM sirtuin by <span class="html-italic">Streptococcus</span> sp. Class U and Class SirTM are more distinct from the other classes. The evolutionary history was inferred using the Neighbor-Joining method [<a href="#B6-molecules-30-00635" class="html-bibr">6</a>]. The optimal tree is shown. The tree is drawn next to the tree scale (upper left corner), with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. The scale length is 0.1, which corresponds to 10 substitutions per 100 positions or 10% sequence divergence in the phylogenetic tree. The bootstrap values (ranging from 0 to 1) are presented by colored branches, with green branches having the highest bootstrap values and red branches having the lowest bootstrap values. A legend for bootstrap values is provided under the tree scale. The evolutionary distances were computed using the p-distance method and are in the units of the number of amino acid differences per sequence. The rate variation among sites was modeled with a gamma distribution (shape parameter = 1). This analysis involved 29 amino acid sequences. All ambiguous positions were removed for each sequence pair (pairwise deletion option). There were a total of 377 positions in the final dataset.</p>
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<p>Distribution of encountered sirtuins among AAB species and their genomes. (<b>A</b>) The sunburst chart at the top left visually represents the hierarchical distribution of three types of sirtuin protein family models: SIR2 (orange), SIR2_2 (yellow), and PRK00481 (green). The innermost circle categorizes these three types, and as you move outward, each segment represents genera and then species. The size of each segment correlates with the number of genomes containing that particular sirtuin. This chart highlights the diversity and prevalence of these sirtuins across different species. The colors of marked sirtuins in sunburst chart correspond to colors in the clustered column charts. Most species have been found to have PRK00481 sirtuins. (<b>B</b>) On the other hand, fewer species have SIR2 and SIR2_2 sirtuins (<b>C</b>,<b>D</b>). Even the number of genomes is averagely higher when looking at the graph of “Distribution of genomes with PRK00481 sirtuins among species”.</p>
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<p>The image depicts the potential catalytic mechanism of NAD<sup>+</sup>-dependent deacetylation by SIR2 family proteins in AAB. This figure has been adapted from <a href="#molecules-30-00635-f004" class="html-fig">Figure 4</a> in A Molecular Perspective on Sirtuin Activity, <span class="html-italic">Int. J. Mol. Sci.</span>, 2020, 21, by Carla S. S. Teixeira et al. [<a href="#B30-molecules-30-00635" class="html-bibr">30</a>].</p>
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<p>NAD<sup>+</sup>-dependent protein deacylase activity path in nicotinate and nicotinamide metabolism of AAB (specifically <span class="html-italic">Entomobacter blattae</span>) identifiable by a red outlined EC 2.3.1.286 [<a href="#B39-molecules-30-00635" class="html-bibr">39</a>].</p>
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<p>Scheme of metabolic pathways of AAB (specifically <span class="html-italic">Entomobacter blattae</span>) [<a href="#B40-molecules-30-00635" class="html-bibr">40</a>]. The red line pathway on the right, above the sign “nicotinate and nicotinamide metabolism”, shows NAD<sup>+</sup>-dependent protein deacylase activity, and the red dot above shows nicotinamide mononucleotide (NMN). The nicotinate and nicotinamide metabolism are a part of a larger network of metabolism of cofactors and vitamins. The network metabolism of cofactors and vitamins is displayed with thickened pink lines and dots. This network is deeply entangled with other metabolism processes, especially with the network of amino acid metabolism displayed with yellow lines and dots.</p>
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<p>Unrooted phylogenetic tree representing positions of AAB sirtuins among representatives of established classes of sirtuins. Sirtuins labeled from SIRT1 to SIRT7, Class U sirtuin, <span class="html-italic">E. coli</span> sirtuin, and SirTM represent the reference sequences, which are surrounded by sequences of different AAB genera. SIRT1-SIRT7 represent human sirtuins, Class U sirtuin is represented by <span class="html-italic">Geobacillus</span> sp., and the SirTM sirtuin by <span class="html-italic">Streptococcus</span> sp. PRK00481 sirtuins of AAB are labeled as “NAD<sup>+</sup>-dependent deacylases” and classified together with <span class="html-italic">E. coli</span> sirtuin and SIRT5 into Class III of sirtuins. SIR2_2 family proteins and SIR2 family proteins are not classified into the known classes of sirtuins, thus we labeled them together as Class SirAAB and separately as subclasses SirAAB-L and SirAAB-S. The accession numbers of sirtuins used for the phylogenetic construction are listed in <a href="#sec3dot5-molecules-30-00635" class="html-sec">Section 3.5</a>. The evolutionary history was inferred using the Neighbor-Joining method [<a href="#B6-molecules-30-00635" class="html-bibr">6</a>]. The optimal tree is shown. The tree is drawn next to the tree scale (upper left corner), with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. The scale length is 0.1, which corresponds to 10 substitutions per 100 positions or 10% sequence divergence in the phylogenetic tree. The bootstrap values (ranging from 0 to 1) are presented by colored branches, with green branches having the highest bootstrap values and red branches having the lowest bootstrap values. A legend for bootstrap values is provided under the tree scale. The evolutionary distances were computed using the p-distance method and are in the units of the number of amino acid differences per sequence. The rate variation among sites was modeled with a gamma distribution (shape parameter = 1). This analysis involved 28 amino acid sequences. All ambiguous positions were removed for each sequence pair (pairwise deletion option). There were a total of 386 positions in the final dataset.</p>
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<p>Results from MEME tool with 20 identified motifs in representative sirtuin sequences and their respective <span class="html-italic">p</span>-values.</p>
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<p>Comparison between SIR2_2 and SIR2 protein motifs. The red line separates SIR2 proteins (above the line) from SIR2_2 proteins (below the line).</p>
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<p>Modelled SIR2 sirtuin (UniProt Acc. No. A0A0U5F059) of <span class="html-italic">Acetobacter senegalensis</span>. The yellow border marks SIR2 domain.</p>
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<p>Inserted NAD<sup>+</sup> and Zn<sup>2+</sup> in SIR2 sirtuin (UniProt Acc. No. A0A0U5F059) using AlphaFold 3 Beta Server from Google DeepMind.</p>
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<p>Modelled SIR2_2 sirtuin (UniProt Acc. No. A0A1A0DNT0) of <span class="html-italic">Acetobacter pasteurianus</span>. The yellow border marks SIR2_2 domain.</p>
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<p>Inserted NAD<sup>+</sup> and Zn<sup>2+</sup> in SIR2_2 sirtuin (UniProt Acc. No. A0A1A0DNT0) using AlphaFold 3 Beta Server from Google DeepMind. Both positions of NAD<sup>+</sup> and Zn<sup>2+</sup> are marked with a red circled area.</p>
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<p>Modelled PRK00481 sirtuin (UniProt Acc. No. A0A252EJJ2) of <span class="html-italic">Acetobacter senegalensis</span>. The yellow border marks PRK00481 domain (<b>A</b>), Zn<sup>2+</sup> binding site, which consists of four cysteines (<b>B</b>), NAD<sup>+</sup> binding site (<b>C</b>), and substrate binding site (<b>D</b>).</p>
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21 pages, 4529 KiB  
Article
NAD+ Suppresses EV-D68 Infection by Enhancing Anti-Viral Effect of SIRT1
by Yue Wang, Haiyu Li, Xia Huang, Yan Huang, Mingqi Lv, Hong Tang, Xinyue Han, Juntong Liu, Yan Liang, Guangchao Zang, Nan Lu and Guangyuan Zhang
Viruses 2025, 17(2), 175; https://doi.org/10.3390/v17020175 - 26 Jan 2025
Viewed by 530
Abstract
Enterovirus 68 (EV-D68) is a non-enveloped virus with a positive-sense single-stranded RNA genome that causes respiratory diseases and acute flaccid myelitis, posing significant threats to human health. However, an effective vaccine remains undeveloped. SIRT1, a nicotinamide adenine dinucleotide (NAD+)-dependent enzyme, plays a key [...] Read more.
Enterovirus 68 (EV-D68) is a non-enveloped virus with a positive-sense single-stranded RNA genome that causes respiratory diseases and acute flaccid myelitis, posing significant threats to human health. However, an effective vaccine remains undeveloped. SIRT1, a nicotinamide adenine dinucleotide (NAD+)-dependent enzyme, plays a key role in cellular metabolism, but its interaction with NAD+ during viral infections is not well understood. In this study, through a metabolomics analysis, we demonstrate that EV-D68 infection influences cellular metabolism. Additionally, we show that NAD+ inhibits EV-D68 infection both in vivo and in vitro. EV-D68 reduces cellular NAD+ levels by regulating the expression of enzymes involved in NAD+ consumption and synthesis. Moreover, the infection increases the expression of sirtuin 1 (SIRT1), which inhibits EV-D68 replication in turn. Mechanistically, SIRT1 suppresses EV-D68 5′UTR-mediated translation, and the antiviral effect of SIRT1 on EV-D68 replication is enhanced by NAD+. Collectively, our findings highlight the critical role of NAD+ metabolism in EV-D68 infection and reveal the antiviral potential of SIRT1, providing valuable insights for the development of antiviral strategies. Full article
(This article belongs to the Section Viral Immunology, Vaccines, and Antivirals)
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Figure 1
<p>EV-D68 infection influences cellular metabolism. RD cells cultured in 10 cm dishes infected with EV-D68 Fermon at an MOI of 1 and non-infected as control. After 18 h infection, cells were harvested for LC-MS analysis (n = 3 samples per group). (<b>a</b>) Principal component analysis of metabolomics data in the mock and EV-D68-infected group. (<b>b</b>) Volcano map of differentially expressed metabolites in EV-D68 compared with that in the mock group. (<b>c</b>) VIP analysis of the top 30 differentially expressed metabolites between the mock and EV-D68 group. The color of each rectangle in the right panel represents the relative level of the metabolites. The metabolites with VIP &gt; 1 and <span class="html-italic">p</span> &lt; 0.05 were determined as significantly different metabolites. The full name of metabolites were shown in in <a href="#app1-viruses-17-00175" class="html-app">Supplementary Tables S1–S4</a>. (<b>d</b>) Pie charts showing the HMDB classifications of the 93 differential metabolites. (<b>e</b>) KEGG pathway enrichment analysis of the significantly altered metabolites between the mock and EV-D68 group.</p>
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<p>NAD+ suppresses EV-D68 proliferation in vitro. (<b>a</b>,<b>b</b>) RD cells were incubated with different concentrations of flavin adenine dinucleotide (FAD), L-Cystathionine (L-Cth), 8-Hydroxyguanosine (8-OHG), L-Acetylcarnitine (ALCAR), or nicotinamide adenine dinucleotide (NAD+) as indicated for 48 h. Then the cell viability was assessed by Cell Counting Kit-8 (CCK-8) assay. RD cells were treated with different concentrations of exogenous FAD (0, 2.5, 5, and 10 µM), 8-OHG (0, 5, 10, and 20 nM), L-Cth (0, 0.1, 0.5, and 1 mM), ALCAR (0, 0.5, 1, and 2 mM), and NAD+ (0, 0.5, 1, and 2 mM) 6 h prior to infection with EV-D68 Fermon at an MOI of 1 for 18 h. Viral VP1 protein levels were assessed by Western blot. (<b>c</b>) As with the cell line and experiment mentioned above, RD cells were treated with different concentrations of exogenous NAD+ (0, 0.5, 1, and 2 mM) 6 h prior to infection with EV-D68 Fermon at an MOI of 1, and after 24 h the supernatant of the cells was collected. Viral titers were determined using TCID50. Data in all quantitative panels are normalized based on β-actin presented as the mean ± SD of n = 3 replicates. Error bars indicate SD (n = 3). “−” represents absence, and “+” represents presence. *** <span class="html-italic">p</span> &lt; 0.001; ns, not significant.</p>
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<p>NAD+ suppresses EV-D68 proliferation in vivo. (<b>a</b>) Schematic representation of the experimental design for NAD+ treatment in neonatal mice infected with EV-D68(ATCC VR-1824). Mice were intracranially inoculated with EV-D68 (1 × 10<sup>5</sup> PFU/mouse) and treated with continuous NAD+ therapy until the seventh day. Viral loads in major organs and tissues were evaluated using RT-qPCR on the 3rd day, and survival rates were monitored until the 14th day. (<b>b</b>) Representative images showing symptoms of healthy mice in the mock group and the mice with limb paralysis in the EV-D68(ATCC VR-1824) infection group on 7 dpi. (<b>c</b>) Bar graph showing the percentage of mice with paralysis between the EV-D68-infected and NAD+ treatment groups. (<b>d</b>,<b>e</b>) Levels of EV-D68 viral nucleic acids and VP1 protein in major organs and muscle tissues were quantified using Western blot and RT-qPCR on the third day. (<b>f</b>) Histopathological changes in tissues from mock, EV-D68-infected, and EV-D68-infected with NAD+ treatment groups (n = 3) were analyzed. Pathological images of spine muscles and hind limb muscles, scale bar = 100 μm. Yellow arrow: Vacuolar degeneration of muscle cells. Brown arrow: Fibrosis of interstitial fibrous connective tissue. Red arrow: Infiltration of lymphocytes and granulocytes. Black arrow: Necrosis of chondrocytes. Pathological images of the spinal cord, scale bar = 50 μm. Blue arrow: Atrophied neurons. Yellow arrow: Proliferation of gliosis. Green arrow: Neuronal necrosis. Orange arrow: Vascular congestion. (<b>g</b>) Day of paralysis onset in mice after injection with EV-D68(ATCC VR-1824). (<b>h</b>) Survival rate statistics for the NAD+ treatment (n = 23) and saline control groups (n = 22) following EV-D68 infection were compared. Data in all quantitative panels are normalized based on β-actin or GAPDH presented as the mean ± SD of n = 3 replicates. Error bars indicate SD (n = 3). “−” represents absence, and “+” represents presence. * <span class="html-italic">p</span> &lt; 0.05; *** <span class="html-italic">p</span> &lt; 0.001; ns, not significant.</p>
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<p>Viral infection regulated the expression of enzymes in the NAD+ salvage pathway, leading to a reduction in NAD+ level. (<b>a</b>) RD cells were cultured in 6-well plates and infected with EV-D68 Fermon at an MOI of 0 or 1 for 24 h. WST—detection of NAD+ in cells by WST-8 reaction colorimetry. (<b>b</b>–<b>e</b>) RD and A549 cells were infected with EV-D68 Fermon at an MOI of 1. Then, 18 h later, the expression changes of NAD+ synthesis genes (Nmnat1 to 3, Nampt, and Nmrk2) and NAD+ consuming genes (Sirt1 to 7, Parp1 to 6, Parp9, 10, 12, 14, and CD38) were measured using RT-qPCR. (<b>f</b>) A549 cells were infected with EV-D68 Fermon at an MOI of 1. Then, 18 h later, the protein levels of VP1, SIRT1, SIRT2, NAMPT, NMNAT2, and CD38, compared to the control β-actin, were determined using Western blot. Data in all quantitative panels are normalized based on β-actin or GAPDH presented as the mean ± SD of n = 3 replicates. Error bars indicate SD (n = 3). “−” represents absence, and “+” represents presence. * <span class="html-italic">p</span> &lt; 0.05; ** <span class="html-italic">p</span> &lt; 0.01; *** <span class="html-italic">p</span> &lt; 0.001.</p>
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<p>NAD+-consuming enzyme SIRT1 inhibits EV-D68 replication. (<b>a</b>) A549 cells were infected with EV-D68 Fermon at a multiplicity of infection (MOI) of 0, 0.5, and 1. Samples were collected after 24 h. Another group were infected with EV-D68 Fermon at an MOI of 1; samples were collected at 0, 8, and 16 h post-infection (hpi). Protein levels of SIRT1 and VP1 were detected using Western blot. (<b>b</b>) RD cells infected with EV-D68 Fermon at an MOI of 1 for 24 h. Cytoplasm extracts (CEs) and nuclear extracts (NEs) were prepared. SIRT1, β-actin, and lamin A expression levels were detected by Western blot analyses using the corresponding antibodies. (<b>c</b>) RD cells were infected with EV-D68 Fermon at an MOI of 1, and SIRT1 localization was assessed by immunofluorescence at 24 hpi. The SIRT1 was stained with the preliminary antibody rabbit anti-SIRT1 and secondary florescent affiliate antibody goat anti-rabbit AlexaFluor488. The nuclei were counterstained with DAPI. Scale bar represents 50 μm. (<b>d</b>–<b>g</b>) 293T cells were transfected with pBudCE4.1-Sirt1 or pBudCE4.1-mtSirt1 at 2, 4 μg, with pBudCE4.1 as the control. After 48 h, cells were infected with EV-D68 Fermon at an MOI of 1 for 24 h. Protein levels of SIRT1 and viral VP1 were quantified by Western blot. The intensity of Western blot band signals was quantified behind by Image J 1.54g (<b>d</b>,<b>f</b>). And viral titers were measured using TCID50 (<b>e</b>,<b>g</b>). (<b>h</b>,<b>i</b>) 293T cells were transfected with si-Sirt1-1, si-Sirt1-2, and si-SIRT1-3 (30 nM), with si-NC as the control, for 48 h. After that, cells were infected with EV-D68 Fermon at an MOI of 1 for 24 h. Protein levels of SIRT1 and viral VP1 were quantified by Western blot. The intensity of Western blot band signals was quantified behind by Image J (<b>h</b>). And viral titers were measured using TCID50 (<b>i</b>). (<b>j</b>,<b>k</b>) RD cells were treated with Resveratrol and Sirtinol in different doses (0, 20, 40 µM). After 8 h, cells were infected with EV-D68 Fermon for 24 h at an MOI of 1. Protein levels of viral VP1 were quantified by Western blot. The intensity of Western blot band signals was quantified behind by Image J. Data in all quantitative panels are normalized based on β-actin or GAPDH presented as the mean ± SD of n = 3 replicates. Error bars indicate SD (n = 3). “−” represents absence, and “+” represents presence. * <span class="html-italic">p</span> &lt; 0.05; ** <span class="html-italic">p</span> &lt; 0.01; *** <span class="html-italic">p</span> &lt; 0.001; ns, not significant.</p>
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<p>NAD+ augments the antiviral effect of SIRT1. (<b>a</b>,<b>b</b>) 293T cells were transfected with si-Sirt1-1 and si-NC for 30 nM; 48 h later, cells were treated with NAD+ for 8 h and then infected with EV-D68 Fermon at an MOI of 1 for 24 h. Protein levels of SIRT1 and viral VP1 were detected by Western blot. The intensity of Western blot band signals was quantified behind by Image J (<b>a</b>). And viral titers were measured using TCID50 (<b>b</b>). (<b>c</b>,<b>d</b>) 293T cells were transfected with si-Sirt1-3 and si-NC for 30 nM. Then, 48 h later, followed the same experiment mentioned before (<b>a</b>,<b>b</b>). (<b>e</b>,<b>f</b>) 293T cells were transfected with pBudCE4.1-Sirt1 and pBudCE4.1 for 2 μg. Then, followed the same experiment mentioned before (<b>a</b>,<b>b</b>). (<b>g</b>) RD cells were treated with NAD+ for 8 h, and SIRT1 localization was assessed by immunofluorescence. The SIRT1 was stained with the preliminary antibody rabbit anti-SIRT1 and secondary florescent affiliate antibody goat anti-rabbit AlexaFluor488. Thr nuclei were counterstained with DAPI. Scale bar represents 10 μm. (<b>h</b>) Schematic presentation of the luciferase reporter plasmid, containing a pol I promoter, the 5′ UTR region of EV-D68, and the Renilla luciferase gene (Rluc) infused with the first 15 bps of EV-D68 ORF, and a Firefly luciferase reporter (Fluc) gene driven by TK promoter. (<b>i</b>) Cells were co-transfected with p5Ferm and either pBudCE4.1-SIRT1 or the control vector. After 24 h, cells were treated with NAD+ for 8 h. Cells were lysed and their Rluc and Fluc activities measured. Determining the ratio of Rluc activity to Fluc activity yielded the relative IRES activity. Data in all quantitative panels are normalized based on β-actin or GAPDH presented as the mean ± SD of n = 3 replicates. Error bars indicate SD (n = 3). “−” represents absence, and “+” represents presence. * <span class="html-italic">p</span> &lt; 0.05; ** <span class="html-italic">p</span> &lt; 0.01; *** <span class="html-italic">p</span> &lt; 0.001; ns, not significant.</p>
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<p>Schematic diagram illustrating the regulatory mechanism of NAD+ and SIRT1 during EV-D68 infection. EV-D68 infection decreases the level of cellular NAD+ (Black arrow: decrease), which promotes the expression of SIRT1. SIRT1 has an inhibitory effect on EV-D68, and it is strengthened by NAD+.</p>
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15 pages, 5367 KiB  
Article
Sirtuin-1 Regulates Mitochondrial Calcium Uptake Through Mitochondrial Calcium Uptake 1 (MICU1)
by Xinyi Zhang, Shuhu Liu, Yanshan Su, Ling Zhang, Ting Guo and Xuemin Wang
Life 2025, 15(2), 174; https://doi.org/10.3390/life15020174 - 25 Jan 2025
Viewed by 572
Abstract
Mitochondria play a central role in cell biological processes, functioning not only as producers of ATP but also as regulators of Ca2+ signaling. Mitochondrial calcium uptake occurs primarily through the mitochondrial calcium uniporter channel (mtCU), with the mitochondrial calcium uptake subunits 1, [...] Read more.
Mitochondria play a central role in cell biological processes, functioning not only as producers of ATP but also as regulators of Ca2+ signaling. Mitochondrial calcium uptake occurs primarily through the mitochondrial calcium uniporter channel (mtCU), with the mitochondrial calcium uptake subunits 1, 2, and 3 (MICU1, MICU2, and MICU3) serving as the main regulatory components. Dysregulated mitochondrial calcium uptake is a hallmark of cellular degeneration. Sirtuin 1 (SIRT1), a key regulator of cellular metabolism, plays a critical role in aging and various neurodegenerative conditions. By blocking SIRT1 using EX527 or shSIRT1, we observed mitochondrial structural fragmentation as well as intensified and prolonged mitochondrial calcium overload. Our study revealed a direct interaction between SIRT1 and MICU1. Notably, SIRT1 inhibition resulted in reduced MICU1 expression, hence led to mitochondrial calcium overload, illustrating the unconventional role of SIRT1 in governing mitochondrial function. Full article
(This article belongs to the Section Physiology and Pathology)
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Figure 1

Figure 1
<p>Expression of SIRT1 in mitochondria of HeLa cells and rat cortical neurons. (<b>a</b>) Western blot analysis of SIRT1 expression in mitochondria, cytoplasm, and whole-cell lysates of HeLa cells. (<b>b</b>) Confocal microscopy determining the SIRT1 colocalization with mitochondria in HeLa cells. Red, MitoTracker; Green, SIRT1. Magnification is 60×. Scale bars, 5 μm. (<b>c</b>) The levels of colocalization between SIRT1 and mitochondria expressed as MCC for a fraction of SIRT1 pixels that are shared with mitochondria (black bar) or vice versa (red bar) in HeLa cells. (<b>d</b>) Confocal microscopy determining the SIRT1 colocalization with mitochondria in SD rat cortical neurons. Red, MitoTracker; Green, SIRT1; Blue, Dapi. Magnification is 60×. Scale bars, 5 μm. (<b>e</b>) The levels of colocalization between SIRT1 and mitochondria expressed as MCC for a fraction of SIRT1 pixels that are shared with mitochondria (black bar) or vice versa (red bar) in SD rat cortical neurons. (<b>f</b>) Representative images of confocal microscopy determining 10 μM of EX527 to mitochondrial morphology in HeLa cells. Red, MitoTracker. Magnification is 60×. Scale bars, 5 μm. (<b>g</b>,<b>h</b>) The footprint of mitochondria and mean branch length of HeLa cells treated with DMSO or EX527 for 1 h. Data presented as mean ± standard deviation (SD). ** <span class="html-italic">p</span> &lt; 0.01, **** <span class="html-italic">p</span> &lt; 0.0001. The number of cells analyzed/the number of independent experiments is indicated in the bars.</p>
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<p>EX527 affected mitochondrial calcium uptake in HeLa cells. (<b>a</b>) Representative confocal microscopy images acquired at 40 s, 76 s, and 160 s depict mitochondrial calcium levels in HeLa cells following treatment with either DMSO or 10 μM EX527 for 1 h. Continuous recording was performed, with one frame captured every 4 s. At the 60 s time point, 100 μM histamine was added. Rhod-2 AM; Magnification is 40×. Scale bars, 20 μm. (<b>b</b>) The mitochondrial calcium level in HeLa cells treated with DMSO or EX527 for 1 h was determined by Rhod-2 AM staining. Overall, 100 μM histamine was used to induce cellular calcium release. (<b>c</b>) The fold change in mitochondrial calcium level in HeLa cells treated with DMSO or EX527 for 1 h, normalized to baseline. (<b>d</b>) Average Rhod-2 AM fluorescence intensity before 100 μM histamine treatment. (<b>e</b>) Maximum fold change in Rhod-2/AM fluorescence intensity after 100 μM histamine treatment. For each group, 30 cells from three independent experiments were analyzed. The data are presented as mean values ± SD. ns, not significant; * <span class="html-italic">p</span> &lt; 0.05.</p>
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<p>shSIRT1 affected mitochondrial calcium uptake in HeLa cells. (<b>a</b>) Representative confocal images (40 s, 76 s, and 160 s) of mitochondrial calcium in HeLa cells co-transfected with shSIRT1 or shSIRT2 interference plasmids and the CMV-mito-R-GECO1 mitochondrial calcium-targeting fluorescence plasmid, followed by treatment with 100 μM histamine to induce cellular calcium release. Continuous recording was performed, with one frame captured every 4 s. At the 60 s time point, 100 μM histamine was added. Red, mito-Red; Magnification is 40×. Scale bars, 50 μm. (<b>b</b>) Mitochondrial calcium fluorescence intensity changes in HeLa cells determined by mito-Red intensity. Overall, 100 μM histamine was used to induce cellular calcium release. (<b>c</b>) The fold change in mitochondrial calcium level in HeLa cells normalized to baseline. (<b>d</b>) Average mitochondrial calcium fluorescence intensity before treatment with 100 μM histamine. (<b>e</b>) Maximum fold change in mitochondrial calcium fluorescence intensity after treatment with 100 μM histamine. (<b>f</b>) The fold change in mitochondrial calcium fluorescence intensity at 300 s. For each group, 30 cells from three independent experiments were analyzed. The data are presented as mean values ± SD. ns, not significant; * <span class="html-italic">p</span> &lt; 0.05; *** <span class="html-italic">p</span> &lt; 0.001; **** <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>MICU1 and SIRT1 interacted with each other. (<b>a</b>–<b>d</b>) SIRT1, MCU, and MICU1 protein expression levels after HeLa cells transfection of shSIRT1 (<span class="html-italic">n</span> = 3 biological replicates; three technical replicates were achieved). (<b>e</b>) GST assay was performed to determine the interaction of SIRT1 and MICU1. Purified GST and GST-SIRT1 proteins were incubated with cell lysate (Input) containing MICU1-HA proteins, followed by examination of the proteins bound to GST and GST-SIRT1 via Western blot analysis. (<b>f</b>) Co-IP was determined in SIRT1 immunoprecipitates by Western blot analysis. SIRT1-flag + pcmv-HA, pcmv-tag4a + MICU1-HA, SIRT1-flag + MICU1-HA, and SIRT1-flag + MICU1-HA constructs were expressed in HeLa cells, and anti-FLAG, anti-HA, and anti-SIRT1 antibodies were employed for immunoprecipitation. (<b>g</b>) SIRT1 and MICU1 exhibited colocalization in HeLa cells. Red, HA; Green, SIRT1. Magnification is 60×. Scale bars, 5 μm. (<b>h</b>) The levels of colocalization between SIRT1 and MICU1-HA expressed as MCC for a fraction of SIRT1 pixels that are shared with HA (black bar) or vice versa (red bar) in HeLa cells. (<b>i</b>) Lysates from rat neurons cultured for 7 days were collected. SIRT1 antibody was utilized for immunoprecipitation, and anti-SIRT1 and anti-MICU1 antibodies were used for Western blot analysis. (<b>j</b>) MICU1-HA was transfected into primary cultured rat neurons, and antibodies targeting HA and SIRT1 were applied as immunofluorescent co-labels. Red, SIRT1; Green, HA. Magnification is 60×. Scale bars, 50 μm. (<b>k</b>) The levels of colocalization between SIRT1 and mitochondria expressed as MCC for a fraction of SIRT1 pixels that are shared with HA (black bar) or vice versa (red bar) in SD rat cortical neurons. The data are presented as mean values ± SD. ns, not significant; * <span class="html-italic">p</span> &lt; 0.05. Statistical analysis was carried out using the Mann–Whitney U Test (<b>b</b>–<b>d</b>). The number of cells analyzed/the number of independent experiments is indicated above the bars.</p>
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<p>SIRT1 regulated mitochondrial calcium uptake through MICU1. (<b>a</b>) HeLa cells were co-transfected with MICU1-HA or pCMV-C-HA, along with the mitochondrial calcium-targeting fluorescent plasmid CMV-mito-R-GECO1. Representative confocal images (40 s, 120 s, and 300 s) of mitochondrial calcium in HeLa cells treated with DMSO or 10 μM EX527 for 1 h. Overall, 100 μM Histamine was used to induce cellular calcium release. Red, mito-Red; Magnification is 40×. Scale bars, 50 μm. Continuous recording was performed, with one frame captured every 4 s. At the 60 s time point, 100 μM histamine was added. (<b>b</b>) The fold change in mitochondrial calcium levels in HeLa cells, normalized to baseline values. (<b>c</b>) Average mitochondrial calcium fluorescence intensity before treatment with 100 μM histamine. (<b>d</b>) The fold change in the peak mitochondrial calcium fluorescence intensity following treatment with 100 μM histamine. For each group, 30 cells from three independent experiments were analyzed (two-way ANOVA and Tukey’s post hoc test). The data are presented as mean values ± SD. ns, not significant; ** <span class="html-italic">p</span> &lt; 0.01.</p>
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