Cells

18 pages, 20003 KiB

Open AccessArticle

ST8SIA6 Sialylates CD24 to Enhance Its Membrane Localization in BRCA

by Jinxia He, Fengchao Zhang, Baihai Wu and Wengong Yu

Cells 2025, 14(1), 9; https://doi.org/10.3390/cells14010009 (registering DOI) - 26 Dec 2024

CD24, a highly sialylated glycosyl-phosphatidyl-inositol (GPI) cell surface protein that interacts with sialic acid-binding immunoglobulin-like lectins (Siglecs), serves as an innate immune checkpoint and plays a crucial role in inflammatory diseases and tumor progression. Recently, cytoplasmic CD24 has been observed in samples from [...] Read more.

CD24, a highly sialylated glycosyl-phosphatidyl-inositol (GPI) cell surface protein that interacts with sialic acid-binding immunoglobulin-like lectins (Siglecs), serves as an innate immune checkpoint and plays a crucial role in inflammatory diseases and tumor progression. Recently, cytoplasmic CD24 has been observed in samples from patients with cancer. However, whether sialylation governs the subcellular localization of CD24 in cancer remains unclear, and the impact of CD24 expression and localization on the clinical prognosis of cancer remains controversial. Here, we performed a systematic pan-cancer analysis of the gene expression levels and clinical correlation of CD24. Our analysis revealed that CD24 was highly expressed in breast tumor tissues and tumor cells, significantly shortening patient survival time. However, this correlation was not evident in other types of cancer. Additionally, a correlation analysis of CD24 levels with sialyltransferases (STs) revealed that ST8SIA6 is the key ST affecting CD24 sialylation. Further investigation demonstrated that ST8SIA6 directly modified CD24, promoting its localization to the cell membrane. Taken together, these findings elucidate, for the first time, the mechanisms by which ST8SIA6 regulates CD24 subcellular localization, providing new insights into the biological functions and applications of CD24. Full article

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The flowchart illustrates the pan-cancer analysis of CD24. Abbreviations: IHC, immunohistochemistry; RNA-seq, RNA sequencing; DBs, databases; TILs, tumor-infiltrating lymphocytes. Full article ">Figure 2
Expression analysis of the CD24 gene in various human cancers. (A) The RNA expression levels of CD24 in human cancers were analyzed using the TIMER algorithm. The statistical significance computed by the Wilcoxon test is annotated by the number of asterisks. * p < 0.05, ** p < 0.01, *** p < 0.001. (B) The RNA expression levels of CD24 in various human cancer cell lines were analyzed using data from the Human Protein Atlas database. Full article ">Figure 3
The clinical relevance of CD24 gene expression levels across various cancer types. (A) The clinical correlation between CD24 gene expression levels and various types of cancer was analyzed using the TIMER algorithm, incorporating key clinical factors, including age, tumor stage, and tumor purity. A heatmap was drawn to show the normalized coefficient of the gene in the Cox model. Z-Score > 0, p < 0.05, increased risk; Z-Score < 0, p < 0.05, decreased risk; p > 0.05, not significant. * p < 0.05, ** p < 0.01, *** p < 0.001. (B) The impact of CD24 levels on the survival rates of patients with BRCA, MESO, and SKCM. HR represents the hazard ratio. (C) The impact of CD24 levels on the survival rates of patients COAD, LGG, and UCS. HR represents the hazard ratio. (D) Spearman’s correlations between CD24 gene expression levels and TILs, including activated CD8+ T cells, activated CD4+ T cells, natural killer cells, activated dendritic cells, macrophages, monocytes, and neutrophils, across various types of human cancers were obtained from the TISIDB database. Rho represents the Spearman’s correlation coefficient. Spearman’s rho > 0, p < 0.05, positive correlation; Spearman’s rho < 0, p < 0.05, negative correlation; p > 0.05, not significant. * p < 0.05, ** p < 0.01, *** p < 0.001. Full article ">Figure 4
The subcellular localization of CD24 protein was analyzed using data from the Human Protein Atlas database. (A) The 13 cancer tissues with the highest levels of CD24 in the cytoplasm and membrane, namely, THCA, HNSC, TGCT, CESC, STAD, BLCA, OV, lung cancer (LUAD and LUSC), PRAD, renal cancer (KICH, KIRC, and KIRP), UCEC, PAAD, and BRCA. (B) Representative immunohistochemical staining images of changes in membranous and cytoplasmic CD24 levels in high- and low-stage tumors from BLCA and PARD patients are shown (scale bar, 100 μm and 25 μm). (C) Representative immunohistochemical staining images of CD24 in the nucleus (scale bar, 100 μm and 20 μm). (D) Representative immunohistochemical staining images of membranous and cytoplasmic CD24 in THCA, TGCT, OV, and BRCA (scale bar, 100 μm and 25 μm). Full article ">Figure 5
The correlations between CD24 levels and the levels of ST8 family members in human cancer were analyzed using the TIMER database. (A) CD24 levels were positively correlated with ST8SIA2 and ST8SIA6 levels in BRCA. Spearman’s rho > 0, p < 0.05, positive correlation; Spearman’s rho < 0, p < 0.05, negative correlation; p > 0.05, not significant. * p < 0.05, ** p < 0.01, *** p < 0.001. (B) The correlations between CD24 and ST8SIA6 levels were analyzed in various human cancers. Spearman’s rho > 0, p < 0.05, positive correlation; Spearman’s rho < 0, p < 0.05, negative correlation; p > 0.05, not significant. * p < 0.05, ** p < 0.01, *** p < 0.001. Full article ">Figure 6
The correlations between Siglec-7/9/10 levels and the abundance of tumor-infiltrating macrophages in BRCA (A) and other human cancers (B) were analyzed using the TIMER database. Spearman’s rho > 0, p < 0.05, positive correlation; Spearman’s rho < 0, p < 0.05, negative correlation; p > 0.05, not significant. * p < 0.05, ** p < 0.01, *** p < 0.001. Full article ">Figure 7
CD24 is directly modified by ST8SIA6. (A) The co-localization of CD24 and Siglec-E Fc fluorescence was observed in 4T1 cells (scale bar, 10 μm). (B) The co-localization of CD24 and Siglec-E fluorescence was observed in TNBC tumor tissues (scale bar, 20 μm and 10 μm). (C) The co-localization of CD24 and ST8SIA6 fluorescence was observed in 4T1 cells (scale bar, 10 μm). (D) The co-localization of CD24 and ST8SIA6 fluorescence was observed in TNBC tumor tissues (scale bar, 50 μm and 10 μm). Full article ">Figure 8
The impact of ST8SIA6 on the subcellular localization and expression of CD24. (A) The expression of ST8SIA6 was detected by western blotting in St8sia6-overexpressing (OE-St8sia6) and St8sia6-knockout (sgSt8sia6) 4T1 cells. (B) The expression of ST8SIA6 was detected by immunofluorescence in OE-St8sia6 and sgSt8sia6 4T1 cells (scale bar, 25 μm). (C) The effects of ST8SIA6 on CD24 expression were detected by flow cytometry. (D) Quantitative analysis of CD24 expression in 4T1 cells. The graph shows the median fluorescence intensity (MFI) of CD24. Data are presented as the mean ± standard error of the mean. The p-values were calculated using a one-way analysis of variance. * p < 0.05, ** p < 0.01. (E) The effect of ST8SIA6 on the subcellular localization of CD24 was determined by immunofluorescence (scale bar, 10 μm). Full article ">

14 pages, 1541 KiB

Open AccessArticle

Chromosomal Abnormalities in Miscarriages and Maternal Age: New Insights from the Study of 7118 Cases

by Anna A. Pendina, Mikhail I. Krapivin, Olga G. Chiryaeva, Lubov’ I. Petrova, Elizaveta P. Pashkova, Arina V. Golubeva, Andrei V. Tikhonov, Alla S. Koltsova, Ekaterina D. Trusova, Dmitrii A. Staroverov, Andrey S. Glotov, Olesya N. Bespalova and Olga A. Efimova

Cells 2025, 14(1), 8; https://doi.org/10.3390/cells14010008 - 26 Dec 2024

Abstract

Chromosomal abnormalities of the embryo are the most common cause of first-trimester pregnancy loss. In this single-center study, we assessed the frequency and the spectrum of chromosomal abnormalities in miscarriages for each year of maternal age from 23 to 44. Cytogenetic data were [...] Read more.

Chromosomal abnormalities of the embryo are the most common cause of first-trimester pregnancy loss. In this single-center study, we assessed the frequency and the spectrum of chromosomal abnormalities in miscarriages for each year of maternal age from 23 to 44. Cytogenetic data were obtained by conventional karyotyping of 7118 miscarriages in women with naturally conceived pregnancies. Chromosomal abnormalities were identified in 67.25% of miscarriages. The total incidence of chromosomal abnormalities increased with maternal aging; however, its average change for a one-year increase in maternal age differed between age spans, equaling 0.704% in the span from 23 to 37 years and 2.095% in the span from 38 to 44 years. At the age of 38 years, the incidence rate surged sharply by 14.79% up to 79.01% and then increased progressively up to 94% in 44-year-old women. The spectrum of chromosomal abnormalities in miscarriages was the same for each year of maternal age from 23 to 44 years. However, the proportions of particular chromosomal abnormalities differed between karyotypically abnormal miscarriages in younger and older women. The proportions of trisomy 16, polyploidy, monosomy X, mosaic abnormalities, and structural rearrangements decreased with increasing maternal age. In contrast, the proportions of multiple aneuploidies and regular trisomies 13, 15, 18, 21, and 22 showed an upward trend with maternal aging. To summarize, despite the increase in the total incidence of chromosomal abnormalities in miscarriages with maternal aging, the rate of change differs for younger and older women, being three times lower in the former than in the latter. Moreover, the proportion of some abnormalities in karyotypically abnormal miscarriages shows a steady growth, whereas the proportion of others becomes increasingly low with maternal aging, most probably due to the age-dependent prevalence of different molecular and cellular defects. Full article

(This article belongs to the Special Issue Molecular Mechanisms of Cell Division and Chromosome Segregation: What Can Go Wrong?)

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28 pages, 27768 KiB

Open AccessArticle

Nootkatone Derivative Nootkatone-(E)-2-iodobenzoyl hydrazone Promotes Megakaryocytic Differentiation in Erythroleukemia by Targeting JAK2 and Enhancing JAK2/STAT3 and PKCδ/MAPK Crosstalk

by Yang Pan, Feng Xiao, Chaolan Pan, Hui Song, Peng Zhao, Meijun Chen, Liejun Huang, Jue Yang and Xiaojiang Hao

Cells 2025, 14(1), 10; https://doi.org/10.3390/cells14010010 (registering DOI) - 26 Dec 2024

Abstract

Erythroleukemia, a complex myeloproliferative disorder presenting as acute or chronic, is characterized by aberrant proliferation and differentiation of erythroid cells. Although nootkatone, a sesquiterpene derived from grapefruit peel and Alaska yellow cedar, has shown anticancer activity predominantly in solid tumors, its effects in [...] Read more.

Erythroleukemia, a complex myeloproliferative disorder presenting as acute or chronic, is characterized by aberrant proliferation and differentiation of erythroid cells. Although nootkatone, a sesquiterpene derived from grapefruit peel and Alaska yellow cedar, has shown anticancer activity predominantly in solid tumors, its effects in erythroleukemia remain unexplored. This study aimed to investigate the impact of nootkatone and its derivatives on erythroleukemia. Our results demonstrate that the nootkatone derivative nootkatone-(E)-2-iodobenzoyl hydrazone (N2) significantly inhibited erythroleukemia cell proliferation in a concentration- and time-dependent manner. More importantly, N2 induced megakaryocytic differentiation, as evidenced by significant morphological changes, and upregulation of megakaryocytic markers CD41 and CD61. In vivo, N2 treatment led to a marked increase in platelet counts and megakaryocytic cell counts. Mechanistically, N2 activated a crosstalk between the JAK2/STAT3 and PKCδ/MAPK signaling pathways, enhancing transcriptional regulation of key factors like GATA1 and FOS. Network pharmacology and experimental validation confirmed that N2 targeted JAK2, and knockdown of JAK2 abolished N2-induced megakaryocytic differentiation, underscoring JAK2’s critical role in erythroleukemia differentiation. In conclusion, N2 shows great promise as a differentiation therapy for erythroleukemia, offering a novel approach by targeting JAK2-mediated signaling pathways to induce megakaryocytic differentiation. Full article

(This article belongs to the Section Cell Signaling)

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20 pages, 3586 KiB

Open AccessReview

Hair Regeneration Methods Using Cells Derived from Human Hair Follicles and Challenges to Overcome

by Ons Ben Hamida, Moon Kyu Kim, Young Kwan Sung, Min Kyu Kim and Mi Hee Kwack

Cells 2025, 14(1), 7; https://doi.org/10.3390/cells14010007 - 25 Dec 2024

Abstract

The hair follicle is a complex of mesenchymal and epithelial cells acquiring different properties and characteristics responsible for fulfilling its inductive and regenerative role. The epidermal and dermal crosstalk induces morphogenesis and maintains hair follicle cycling properties. The hair follicle is enriched with [...] Read more.

The hair follicle is a complex of mesenchymal and epithelial cells acquiring different properties and characteristics responsible for fulfilling its inductive and regenerative role. The epidermal and dermal crosstalk induces morphogenesis and maintains hair follicle cycling properties. The hair follicle is enriched with pluripotent stem cells, where dermal papilla (DP) cells and dermal sheath (DS) cells constitute the dermal compartment and the epithelial stem cells existing in the bulge region exert their regenerative role by mediating the epithelial–mesenchymal interaction (EMI). Many studies have developed and focused on various methods to optimize the EMI through in vivo and in vitro approaches for hair regeneration. The culturing of human hair mesenchymal cells resulted in the loss of trichogenicity and inductive properties of DP cells, limiting their potential application in de novo hair follicle generation in vivo. Epithelial stem cells derived from human hair follicles are challenging to isolate and culture, making it difficult to obtain enough cells for hair regeneration purposes. Mesenchymal stem cells and epithelial stem cells derived from human hair follicles lose their ability to form hair follicles during culture, limiting the study of hair follicle formation in vivo. Therefore, many attempts and methods have been developed to overcome these limitations. Here, we review the possible and necessary cell methods and techniques used for human hair follicle regeneration and the restoration of hair follicle cell inductivity in culture. Full article

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Morphology and markers of cells isolated and cultured from human hair follicles. These are the results of staining with various markers after isolating and culturing cells from human hair follicles. The image shows dermal papilla (DP) cells after two weeks of culture, expressing a-SMA, versican, and ALP in cultured DP cells (passage 1). Outer root sheath (ORS) cells were isolated and cultured from the ORS derived from the epithelium, and the image shows the cells on day 10. Keratin 1–3 were strongly expressed, while keratin 17 and 19 were not expressed. Additionally, sebocytes were isolated and cultured from human sebaceous glands (SG), with the image showing the cells on day 10. These sebocytes strongly expressed keratin 17 and keratin 19, and lipid secretion was observed through Oil Red O and Nile Red staining, adapted with permission from Ref. [<a href="#B80-cells-14-00007" class="html-bibr">80</a>]. Full article ">Figure 2
Method to restore the trichogenicity of cultured human dermal papilla (DP) cells or epithelial stem cells (Epi stem cells). Cultured human epithelial stem cells (Epi stem cells) are induced into iPSCs, mixed with mouse dermal cells, and utilized in hair regeneration assays to promote hair follicle formation. Cultured dermal papilla cells (DP cells) recover their hair follicle regenerative ability through iPSC induction, 3D cultures, or treatment with small molecules, inhibitors, or exosomes. These treated DP cells are then combined with mouse epidermal cells and employed in hair regeneration assays to induce hair follicle formation. Full article ">Figure 3
Currently reported methods for hair regeneration using cultured cells. This describes the models used to evaluate hair regeneration with isolated cells reported to date. Patch Assay: In this model, epidermal and dermal cells are mixed and injected subcutaneously into a nude mouse. Hair follicle formation can be observed two weeks later. Hair follicles do not form when using mouse dermal or epidermal cells alone, but mixing both types of cells results in hair follicle formation after two weeks. Chamber Assay: A chamber is inserted into a cut in the skin of a nude mouse, and a mixture of mouse dermal and epidermal cells is added to the chamber. Two weeks later, the chamber is removed, revealing a layer formed by the two cell types. By four weeks, hair follicle formation can be observed. Sandwich Assay: Dermal cells are placed between the epidermis and dermis of the footpad or sole skin, and the tissue is xenografted into another mouse. Hair follicle formation potential is then evaluated. Hair Germ Assay: Dermal and epidermal cells are mixed into a collagen gel drop, which is then injected into a nude mouse. Hair follicle formation is observed. Bearding Skin Organoid: Human pluripotent stem cells (hPSCs) are induced into iPSCs and treated with various chemicals to induce hair follicles in vitro. Full article ">

17 pages, 2689 KiB

Open AccessArticle

Ezrin Polarization as a Diagnostic Marker for Circulating Tumor Cells in Hepatocellular Carcinoma

by Ibrahim Büdeyri, Olaf Guckelberger, Elsie Oppermann, Dhruvajyoti Roy, Svenja Sliwinski, Felix Becker, Benjamin Struecker, Thomas J. Vogl, Andreas Pascher, Wolf O. Bechstein, Anna Lorentzen, Mathias Heikenwalder and Mazen A. Juratli

Cells 2025, 14(1), 6; https://doi.org/10.3390/cells14010006 - 25 Dec 2024

Abstract

Hepatocellular carcinoma (HCC) is the sixth most common cancer and the third leading cause of cancer-related death worldwide, with no precise method for early detection. Circulating tumor cells (CTCs) expressing the dynamic polarity of the cytoskeletal membrane protein, ezrin, have been proposed to [...] Read more.

Hepatocellular carcinoma (HCC) is the sixth most common cancer and the third leading cause of cancer-related death worldwide, with no precise method for early detection. Circulating tumor cells (CTCs) expressing the dynamic polarity of the cytoskeletal membrane protein, ezrin, have been proposed to play a crucial role in tumor progression and metastasis. This study investigated the diagnostic and prognostic potential of polarized circulating tumor cells (p-CTCs) in HCC patients. CTCs were isolated from the peripheral blood of 20 HCC patients and 18 patients with nonmalignant liver disease (NMLD) via an OncoQuick^® kit and immunostained with Ezrin-Alexa Fluor 488^®, CD146-PE, and CD45-APC. A fluorescence microscopy was then performed for analysis. The HCC group exhibited significantly higher levels of p-CTCs, with median values of 0.56 p-CTCs/mL, compared to 0.02 p-CTCs/mL (p = 0.03) in the NMLD group. CTCs were detected in 95% of the HCC patients, with a sensitivity of 95% and specificity of 89%. p-CTCs were present in 75% of the HCC patients, with a sensitivity of 75% and a specificity of 94%. Higher p-CTC counts were associated with the significantly longer overall survival in HCC patients (p = 0.05). These findings suggest that p-CTCs could serve as valuable diagnostic and prognostic markers for HCC. The incorporation of p-CTCs into diagnostic strategies could enhance therapeutic decision-making and improve patient outcomes. Full article

(This article belongs to the Collection Current Understanding in Cancer Treatment and Monitoring through Identification of Circulating Tumor Cells and Tumor-Derived Extracellular Vesicles 2023)

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Schematic representation of the workflow. Created in BioRender. Juratli, M. (2023) BioRender.com/k09p009. Full article ">Figure 2
Examples of polarized CTCs from individual patient samples (A–J). Anti-Ezrin-Alexa Fluor 488 (green), nuclear staining with DAPI (blue), CD146 (red), leukocyte/CD45 (violet) and merged images of all the fluorescence channels. Observed at 40× magnification. Full article ">Figure 3
Boxplots comparing (A) CTCs and (B) p-CTCs between patients with HCC and those with NMLD. The lines within each box represent the median values, the boxes’ limits indicate the first and third quartiles, and the whiskers represent the smallest and largest values within 1.5 times of the IQRs from the first and third quartiles. p-values and ξ-effect sizes were determined using one-way ANOVA, and p < 0.05 was considered significant. Full article ">Figure 4
Kaplan–Meier analysis of HCC patients with and without p-CTCs. (A) Overall survival (OS) curve and (B) recurrence-free survival (RFS) curve. HCC patients with p-CTCs exhibited a longer mean overall survival (40 ± 8 months vs. 26 ± 22 months, p = 0.05). However, the difference in mean recurrence-free survival between HCC patients with and without p-CTCs was not statistically significant (36 ± 13 months vs. 25 ± 22 months, respectively; p = 0.20). Full article ">Figure 5
Forest plot of hazard ratios for age > 70 years (A), metastasis (B), p-CTC (C), recurrence (D) and tumor size >5 cm (E) in HCC patients. Hazard ratios were calculated via univariate Cox regression analysis. Full article ">

32 pages, 2719 KiB

Open AccessReview

Metabolomics-Driven Biomarker Discovery for Breast Cancer Prognosis and Diagnosis

by Rasanpreet Kaur, Saurabh Gupta, Sunanda Kulshrestha, Vishal Khandelwal, Swadha Pandey, Anil Kumar, Gaurav Sharma, Umesh Kumar, Deepak Parashar and Kaushik Das

Cells 2025, 14(1), 5; https://doi.org/10.3390/cells14010005 - 25 Dec 2024

Abstract

Breast cancer is a cancer with global prevalence and a surge in the number of cases with each passing year. With the advancement in science and technology, significant progress has been achieved in the prevention and treatment of breast cancer to make ends [...] Read more.

Breast cancer is a cancer with global prevalence and a surge in the number of cases with each passing year. With the advancement in science and technology, significant progress has been achieved in the prevention and treatment of breast cancer to make ends meet. The scientific intradisciplinary subject of “metabolomics” examines every metabolite found in a cell, tissue, system, or organism from different sources of samples. In the case of breast cancer, little is known about the regulatory pathways that could be resolved through metabolic reprogramming. Evidence related to the significant changes taking place during the onset and prognosis of breast cancer can be obtained using metabolomics. Innovative metabolomics approaches identify metabolites that lead to the discovery of biomarkers for breast cancer therapy, diagnosis, and early detection. The use of diverse analytical methods and instruments for metabolomics includes Magnetic Resonance Spectroscopy, LC/MS, UPLC/MS, etc., which, along with their high-throughput analysis, give insights into the metabolites and the molecular pathways involved. For instance, metabolome research has led to the discovery of the glutamate-to-glutamate ratio and aerobic glycolysis as biomarkers in breast cancer. The present review comprehends the updates in metabolomic research and its processes that contribute to breast cancer prognosis and metastasis. The metabolome holds a future, and this review is an attempt to amalgamate the present relevant literature that might yield crucial insights for creating innovative therapeutic strategies aimed at addressing metastatic breast cancer. Full article

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18 pages, 1835 KiB

Open AccessReview

Calcium Signalling in Neurological Disorders, with Insights from Miniature Fluorescence Microscopy

by Dechuan Sun, Mona Amiri, Qi Meng, Ranjith R. Unnithan and Chris French

Cells 2025, 14(1), 4; https://doi.org/10.3390/cells14010004 - 25 Dec 2024

Abstract

Neurological disorders (NDs), such as amyotrophic lateral sclerosis (ALS), Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and schizophrenia, represent a complex and multifaceted health challenge that affects millions of people around the world. Growing evidence suggests that disrupted neuronal calcium signalling [...] Read more.

Neurological disorders (NDs), such as amyotrophic lateral sclerosis (ALS), Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and schizophrenia, represent a complex and multifaceted health challenge that affects millions of people around the world. Growing evidence suggests that disrupted neuronal calcium signalling contributes to the pathophysiology of NDs. Additionally, calcium functions as a ubiquitous second messenger involved in diverse cellular processes, from synaptic activity to intercellular communication, making it a potential therapeutic target. Recently, the development of the miniature fluorescence microscope (miniscope) enabled simultaneous recording of the spatiotemporal calcium activity from large neuronal ensembles in unrestrained animals, providing a novel method for studying NDs. In this review, we discuss the abnormalities observed in calcium signalling and its potential as a therapeutic target for NDs. Additionally, we highlight recent studies that utilise miniscope technology to investigate the alterations in calcium dynamics associated with NDs. Full article

(This article belongs to the Special Issue New Discoveries in Calcium Signaling-Related Neurological Disorders)

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A typical structure of a conventional fluorescence microscope and the miniscope. (a) Conventional fluorescence microscope. (b) Miniscope: An LED emits light at a wavelength that excites the fluorophore, which is collimated by a half-ball lens. The excitation light passes through an excitation filter to reduce background noise before being reflected by a dichroic mirror. A GRIN lens focuses the light to activate fluorophores in neurons and collects the fluorescent signals. These signals are then directed back through the dichroic mirror and an emission filter, isolating the desired wavelength. Then, an achromatic lens focuses the signals onto a CMOS sensor. Full article ">Figure 2
The miniscope facilitates the recording of neuronal calcium signals in freely moving mice. (a) An example of a C57BL/6 mouse wearing the UCLA miniscope (version 3). (b) A representative image showing hippocampal CA1 neurons captured using the miniscope. Neurons are labelled with GCamp6f. Typically, over 100 neurons can be observed within the field of view. Full article ">Figure 3
An example of using the miniscope to study the calcium activity of hippocampal neurons in mice. (a) A mouse wearing a miniscope traverses a linear track. (b) An example showing that the calcium activity of hippocampal neurons exhibits spatial sensitivity when mice traverse a linear track. (c) An example of raw fluorescent intensity in the detected neurons captured by the miniscope. (d) An example of a neuron’s deconvolved calcium activity. Full article ">

19 pages, 4415 KiB

Open AccessReview

Ca²⁺/Calmodulin-Dependent Protein Kinase II (CaMKII) Regulates Basal Cardiac Pacemaker Function: Pros and Cons

by Tatiana M. Vinogradova and Edward G. Lakatta

Cells 2025, 14(1), 3; https://doi.org/10.3390/cells14010003 - 25 Dec 2024

Abstract

The spontaneous firing of the sinoatrial (SA) node, the physiological pacemaker of the heart, is generated within sinoatrial nodal cells (SANCs) and is regulated by a “coupled-clock” pacemaker system, which integrates a “membrane clock”, the ensemble of ion channel currents, and an intracellular [...] Read more.

The spontaneous firing of the sinoatrial (SA) node, the physiological pacemaker of the heart, is generated within sinoatrial nodal cells (SANCs) and is regulated by a “coupled-clock” pacemaker system, which integrates a “membrane clock”, the ensemble of ion channel currents, and an intracellular “Ca²⁺ clock”, sarcoplasmic reticulum-generated local submembrane Ca²⁺ releases via ryanodine receptors. The interactions within a “coupled-clock” system are modulated by phosphorylation of surface membrane and sarcoplasmic reticulum proteins. Though the essential role of a high basal cAMP level and PKA-dependent phosphorylation for basal spontaneous SANC firing is well recognized, the role of basal CaMKII-dependent phosphorylation remains uncertain. This is a critical issue with respect to how cardiac pacemaker cells fire spontaneous action potentials. This review aspires to explain and unite apparently contradictory results of pharmacological studies in the literature that have demonstrated a fundamental role of basal CaMKII activation for basal cardiac pacemaker function, as well as studies in mice with genetic CaMKII inhibition which have been interpreted to indicate that basal spontaneous SANC firing is independent of CaMKII activation. The assessment of supporting and opposing data regarding CaMKII effects on phosphorylation of Ca²⁺-cycling proteins and spontaneous firing of SANC in the basal state leads to the necessary conclusion that CaMKII activity and CaMKII-dependent phosphorylation do regulate basal cardiac pacemaker function. Full article

(This article belongs to the Section Cellular Metabolism)

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22 pages, 1693 KiB

Open AccessReview

Caveolin-Mediated Endocytosis: Bacterial Pathogen Exploitation and Host–Pathogen Interaction

by Dibyasri Barman and Rishi Drolia

Cells 2025, 14(1), 2; https://doi.org/10.3390/cells14010002 - 24 Dec 2024

Abstract

Within mammalian cells, diverse endocytic mechanisms, including phagocytosis, pinocytosis, and receptor-mediated endocytosis, serve as gateways exploited by many bacterial pathogens and toxins. Among these, caveolae-mediated endocytosis is characterized by lipid-rich caveolae and dimeric caveolin proteins. Caveolae are specialized microdomains on cell surfaces that [...] Read more.

Within mammalian cells, diverse endocytic mechanisms, including phagocytosis, pinocytosis, and receptor-mediated endocytosis, serve as gateways exploited by many bacterial pathogens and toxins. Among these, caveolae-mediated endocytosis is characterized by lipid-rich caveolae and dimeric caveolin proteins. Caveolae are specialized microdomains on cell surfaces that impact cell signaling. Caveolin proteins facilitate the creation of caveolae and have three members in vertebrates: caveolin-1, caveolin-2, and caveolin-3. Many bacterial pathogens hijack caveolin machinery to invade host cells. For example, the Gram-positive facultative model intracellular bacterial pathogen Listeria monocytogenes exploits caveolin-mediated endocytosis for efficient cellular entry, translocation across the intestinal barrier, and cell–cell spread. Caveolin facilitates the internalization of group A streptococci by promoting the formation of invaginations in the plasma membrane and avoiding fusion with lysosomes, thereby aiding intracellular survival. Caveolin plays a crucial role in internalizing and modulation of host immune responses by Gram-negative bacterial pathogens, such as Escherichia coli K1, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Salmonella enterica serovar Typhimurium. Here, we summarize how bacterial pathogens manipulate the host’s caveolin system to facilitate bacterial entry and movement within and between host cells, to support intracellular survival, to evade immune responses, and to trigger inflammation. This knowledge enhances the intervention of new therapeutic targets against caveolin in microbial invasion and immune evasion processes. Full article

(This article belongs to the Special Issue Function and Dysfunction of the Caveolar Network in Cell Signaling and Human Disease: An Update after 70 Years of the Discovery of Caveolae)

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Schematic depicting the mechanism of L. monocytogenes LAP and caveolin-mediated translocation across the intestinal epithelial barrier and subsequent InlA-mediated internalization across non-phagocytic cells. LAP on L. monocytogenes binds to its host cell surface receptor heat shock protein 60 (Hsp60), inducing endocytosis of tight junction proteins, claudin-1, occludin, and the adherens junction protein E-cadherin via caveolin-1 and MLCK-mediated endocytosis. This disrupts cell junctions, allowing L. monocytogenes to pass through the paracellular spaces. InlA subsequently binds to its receptor E-cadherin at the adherens junctions to mediate transcytosis across the epithelial barrier. In non-phagocytic cells, the bacterial surface protein InlA and InlB interact with E-cadherin and c-met, leading to the cytoskeletal rearrangement via a zipper mechanism that triggers L. monocytogenes internalization through PI3-K activation and caveolin-mediated endocytosis. Figure created using Biorender and adapted from [<a href="#B43-cells-14-00002" class="html-bibr">43</a>]. Full article ">Figure 2
Schematic representation of the cell-to-cell spread mechanism of L. monocytogenes in phagocytic and non-phagocytic cells. In phagocytic cells (left), internalized actin protrusions containing L. monocytogenes secrete LLO, which disrupts phosphatidyl serine on the plasma membrane. Both actin protrusions and phosphatidyl serine-positive L. monocytogenes bind to the TIM4 receptor on the host cell surface, which causes internalization of L. monocytogenes via caveolin-mediated endocytosis. In non-phagocytic cells (right), when actin filament-rich protrusions containing the bacteria extend from one cell, they bind to ubiquitinated E-cadherin in adjacent cells. This binding triggers caveolae to form a flattened invagination that wraps around these bacterial protrusions, effectively engulfing them with the help of some core proteins of caveolae, such as Cav-1, Cav-2, a subset of the caveolin-associated proteins (cavin-2 and EHD2), and clathrin-interacting Epsin that assists in bending the membrane to create these invaginations. Figure created using Biorender. Full article ">Figure 3
Schematics depicting the internalization mechanism of P. gingivalis and Leptospira via caveolin-mediated endocytosis. (A) The interaction of the virulent factor RgpA of P. gingivalis with Cav-1 in the host cell facilitates the internalization of P. gingivalis via caveolae. P. gingivalis inhibits the integrity of Mfsd2a, leading to enhanced transcytosis across the blood–brain barrier and increased Cav-1 expression, which induces albumin uptake to the cell (adapted from [<a href="#B89-cells-14-00002" class="html-bibr">89</a>]). (B) Leptospiral species interacts with integrin-β-1 on host cells; it triggers caveolin to form an invagination; and through the caveolae/integrin-b1-PI3K/FAK-microfilament endocytosis pathway, it enters the host cell. To avoid fusion with lysosomes, it forms leptospiral vesicles inside the host cell, and these vesicles recruit Rab5/Rab11 and Sec/Exo-SNARE proteins in endocytic recycling and vesicular transport systems for intracellular migration and finally release from the cells through a SNARE complex-mediated FAK/microfilament/microtubule endocytosis pathway. Figure created using Biorender. Full article ">

36 pages, 11803 KiB

Open AccessArticle

Interplay of Transcriptomic Regulation, Microbiota, and Signaling Pathways in Lung and Gut Inflammation-Induced Tumorigenesis

by Beatriz Andrea Otálora-Otálora, César Payán-Gómez, Juan Javier López-Rivera, Natalia Belén Pedroza-Aconcha, Sally Lorena Arboleda-Mojica, Claudia Aristizábal-Guzmán, Mario Arturo Isaza-Ruget and Carlos Arturo Álvarez-Moreno

Cells 2025, 14(1), 1; https://doi.org/10.3390/cells14010001 - 24 Dec 2024

Abstract

Inflammation can positively and negatively affect tumorigenesis based on the duration, scope, and sequence of related events through the regulation of signaling pathways. A transcriptomic analysis of five pulmonary arterial hypertension, twelve Crohn’s disease, and twelve ulcerative colitis high throughput sequencing datasets using [...] Read more.

Inflammation can positively and negatively affect tumorigenesis based on the duration, scope, and sequence of related events through the regulation of signaling pathways. A transcriptomic analysis of five pulmonary arterial hypertension, twelve Crohn’s disease, and twelve ulcerative colitis high throughput sequencing datasets using R language specialized libraries and gene enrichment analyses identified a regulatory network in each inflammatory disease. IRF9 and LINC01089 in pulmonary arterial hypertension are related to the regulation of signaling pathways like MAPK, NOTCH, human papillomavirus, and hepatitis c infection. ZNF91 and TP53TG1 in Crohn’s disease are related to the regulation of PPAR, MAPK, and metabolic signaling pathways. ZNF91, VDR, DLEU1, SATB2-AS1, and TP53TG1 in ulcerative colitis are related to the regulation of PPAR, AMPK, and metabolic signaling pathways. The activation of the transcriptomic network and signaling pathways might be related to the interaction of the characteristic microbiota of the inflammatory disease, with the lung and gut cell receptors present in membrane rafts and complexes. The transcriptomic analysis highlights the impact of several coding and non-coding RNAs, suggesting their relationship with the unlocking of cell phenotypic plasticity for the acquisition of the hallmarks of cancer during lung and gut cell adaptation to inflammatory phenotypes. Full article

(This article belongs to the Topic Inflammatory Tumor Immune Microenvironment)

► Show Figures

Figure 1

Figure 1
Venn diagram with the transcriptomic metafirm in common and unique to each type of inflammatory disease. Created with BioRender.com. Full article ">Figure 2
Coding (lilium and grey) and non-coding (purple) transcriptional regulatory network (cncTRN) of key upregulated transcription factors (TFs) and lncRNA in pulmonary arterial hypertension (PAH). Created with Cytoscape. Full article ">Figure 3
Coding (lilium and grey) and non-coding (purple) transcriptional regulatory network (cncTRN) of key upregulated transcription factors in CD. Created with Cytoscape. Full article ">Figure 4
Coding (lilium and grey) and non-coding (purple) transcriptional regulatory network (cncTRN) of key upregulated transcription factors in ulcerative colitis. Created with Cytoscape. Full article ">Figure 5
Microbiome interaction with membrane receptor of PAH-related cells activating signaling pathways involved in transcriptional regulation during lung inflammation. In red are the upregulated genes and TFs; in black are the key upregulated TFs. Created with BioRender.com. Full article ">Figure 6
Microbiome interaction with membrane receptor of CD-related cells, activating signaling pathways involved in transcriptional regulation during gut inflammation. In red are the upregulated genes and TFs; in black are the key upregulated TFs. Created with BioRender.com. Full article ">Figure 7
Microbiome interaction with membrane receptor of UC-related cells, activating signaling pathways involved in transcriptional regulation during gut inflammation. In red are the upregulated genes and TFs; in black are the key upregulated TFs. Created with BioRender.com. Full article ">

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Cells, Volume 14, Issue 1 (January-1 2025) – 10 articles

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