Search Results (1,051)

Previous studies have revealed that muscle atrophy emerges as a significant challenge faced by astronauts during prolonged missions in space. A loss in muscle mass results in a weakening of skeletal muscle strength and function, which will not only contribute to a decline in overall physical performance but also elevate the risk of various age-related diseases. Skeletal muscle atrophy in the microgravity environment is thought to be associated with changes in energy metabolism, protein metabolism, calcium ion homeostasis, myostatin levels, and apoptosis. Modulating some pathways could be a promising approach to mitigating muscle atrophy in the microgravity environment. This review serves as a comprehensive summary of research on the impact of microgravity on skeletal muscle, with the aim of providing insights into its pathogenesis and the development of effective treatments. Full article

Background and Objectives: Uric acid (UA) and the markers of mineral bone metabolism and inflammation are commonly altered in patients with chronic kidney disease (CKD) and are associated with the risk of cardiovascular complications and death. Studies point to a link between high serum UA and mineral bone homeostasis and inflammation, but controversy remains. The aim of this study was to evaluate the relationship between UA levels and mineral bone metabolism and inflammation biomarkers in a sample of Mexican patients with CKD 3a–5. Materials and Methods: This cross-sectional study included 146 Mexican patients with CKD 3a–5. In addition, 25 healthy subjects were included in the study with the aim of generating reference data for comparisons. Metabolic parameters including UA serum concentrations, mineral bone metabolism (parathormone (PTH), fibroblast growth factor 23 (FGF23), calcium, and phosphate), and inflammation (interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-α)) biomarkers were measured in all of the samples and compared as a function of the estimated glomerular function rate (eGFR) or UA levels. Results: Intact PTH, FGF23, and cytokines were higher in advanced CKD stages. Patients with hyperuricemia had significantly higher values of FGF23 and TNF-α compared with those without hyperuricemia. The eGFR was found to be significantly and negatively correlated with all markers. Uric acid was significantly correlated with phosphate, iPTH, FGF23, and TNF-α, whereas iPTH was significantly correlated with FGF23, TNF-α, and FGF23. Finally, a multivariate analysis confirmed the relationship of eGFR with all the tested biomarkers, as well as other relationships of iPTH with UA and TNF-α and of FGF23 with UA and TNF-α. Conclusions: This study supports the relationship between uric acid and levels of mineral bone metabolism and inflammation biomarkers in patients with CKD at middle to advanced stages. In the follow-up of patients with CKD, monitoring and controlling UA levels through nutritional or pharmacological interventions could help in the prevention of alterations related to mineral bone metabolism. Full article

The endoplasmic reticulum (ER) is a key organelle in cellular homeostasis, regulating calcium levels and coordinating protein synthesis and folding. In neurons, the ER forms interconnected sheets and tubules that facilitate the propagation of calcium-based signals. Calcium plays a central role in the modulation and regulation of numerous functions in excitable cells. It is a versatile signaling molecule that influences neurotransmitter release, muscle contraction, gene expression, and cell survival. This review focuses on the intricate dynamics of calcium signaling in hippocampal neurons, with particular emphasis on the activation of voltage-gated and ionotropic glutamate receptors in the plasma membrane and ryanodine and inositol 1,4,5-trisphosphate receptors in the ER. These channels and receptors are involved in the generation and transmission of electrical signals and the modulation of calcium concentrations within the neuronal network. By analyzing calcium fluctuations in neurons and the associated calcium handling mechanisms at the ER, mitochondria, endo-lysosome and cytosol, we can gain a deeper understanding of the mechanistic pathways underlying neuronal interactions and information transfer. Full article

Calcium ions (Ca²⁺) are vital intracellular messengers that regulate a multitude of neuronal functions, including synaptic transmission, plasticity, exocytosis, and cell survival. Neuronal cell death can occur through a variety of mechanisms, including excitotoxicity, apoptosis, and autophagy. In the context of excitotoxicity, the excessive release of glutamate in the synapses can trigger the activation of postsynaptic receptors. Upon activation, Ca²⁺ influx into the cell from the extracellular space via their associated ion channels, most notably L-type Ca²⁺ channels. Previous studies have indicated that α-synuclein (α-syn), a typical cytosolic protein, plays a significant role in the pathogenesis of Parkinson’s disease (PD). It is also worth noting that the aggregated form of α-syn has the capacity to affect Ca²⁺ homeostasis by altering the function of Ca²⁺ regulation. The upregulation of leucine-rich repeat kinase 2 (LRRK2) is closely associated with PD pathogenesis. LRRK2 mutants exhibit a dysregulation of calcium signaling, resulting in dopaminergic neuronal degeneration. It could therefore be proposed that α-syn and LRRK2 play important roles in the mechanisms underlying Ca²⁺ dyshomeostasis and excitotoxicity in PD. Full article

Ion channels are essential for mineral ion homeostasis in mammalian cells, and these are activated or inhibited by environmental stimuli such as heat, cold, mechanical, acidic, or basic stresses. These expressions and functions are quite diverse between cell types. The function and importance of ion channels are well-studied in neurons and cardiac cells, while those functions in pluripotent stem cells (PSCs) were not fully understood. Some sodium, potassium, chloride, calcium, transient receptor potential channels and mechanosensitive Piezo channels are found to be expressed and implicated in pluripotency and self-renewal capacity in PSCs. This review summarizes present and previous reports about ion channels and their response to environmental stimuli in PSCs. Furthermore, we compare the expressions and roles between PSCs and their differentiated embryoid bodies. We then discuss those contributions to pluripotency and differentiation. Full article

Vitamin D is a conditionally essential fat-soluble vitamin found in foods such as fish; fish oil; egg yolks; animal fats; some mushroom varieties; and fortified foods such as cheese, margarine, milk, infant formula, and some ready-to-eat cereals. Calcium (Ca) is found in milk, cheese, canned fish, ready-to-eat cereals, milk substitutes, dark green leafy vegetables, and sports drinks. There are more than fifty metabolites of vitamin D. Vitamin D participates in immune regulation, apoptosis induction, insulin secretion, inflammation, cell differentiation, calcium balance and regulation, bone mineralization, and phosphorus homeostasis. Ca is an essential macro-mineral involved in bone and teeth matrices, strength, and hardness; muscle and cardiovascular movement; neurological messaging; and in the release of hormones. Peer-reviewed journal articles were accessed from the search engine PubMed. The authors reviewed the references in the peer-reviewed journal articles, websites, and review articles if the authors proposed a new theory or mechanism. Vitamin D and Ca have important relationships; therefore, many factors may impede or interfere with the body’s ability to absorb or utilize vitamin D and or Ca and may result in low or excessive levels of each. Additionally, genetic/medically related absorption issues and low intake may also result in deficiencies. This review discusses the introduction of each, their functions, absorption, somatic transportation, the relationship between vitamin D and Ca, and recommendations and supplementation strategies if available. Full article

The findings regarding trace element concentrations in patients diagnosed with type 2 diabetes and healthy controls are inconsistent, and therefore, we determined to gather them in the form of a review to further indicate the need for more advanced knowledge development. In our study, we reviewed articles and studies that involved the topics of micronutrient and metal associations with the occurrence and development of type 2 diabetes. We mainly included works regarding human-based studies, but with limited research results, animal-based research was also taken into account. With some newer studies, we reached for initial assumptions of previous statements. The results indicated that higher serum levels of lead, cadmium, arsenic, bromine, barium, strontium, nickel, aluminum, calcium, copper, and ferritin are positively associated with diabetic prevalence. Both too-low and too-high levels of zinc, selenium, and magnesium may be connected to the development of diabetes. Chromium has the capability of insulin response modulation, with enhanced insulin-cell binding, and thus, lower serum levels of chromium can be found in diabetic patients. There are contradictory discoveries regarding manganese. Its supplementation can possibly cease the development of insulin resistance and type 2 diabetes. On the contrary, other studies reported that there is no such connection. Our work indicates that, as micronutrients play a significant role in the pathogenesis of metabolic disorders, more research regarding their bodily homeostasis and type 2 diabetes should be conducted. Full article

The IV subfamily of receptor-like cytoplasmic kinase (RLCK-IV), known as calcium-binding receptor-like cytoplasmic kinases (CRCKs), plays a vital role in plant signal transduction, particularly in coordinating growth and responses to abiotic stresses. However, our comprehension of CRCK genes in Populus deltoides, a species characterized as fast-growing and pest-resistant but with drought intolerance, is limited. Here, we identify 6 members of the CRCK subfamily on a genome-wide scale in P. deltoides, denoted as PdeCRCK1–PdeCRCK6. An evolutionary and structural analysis revealed highly conserved kinase catalytic domains across all PdeCRCKs, characterized by calmodulin (CaM)-binding sites and serine (Ser)/threonine (Thr) phosphorylation sites. The cis-acting elements of promoters indicated the presence of responsive elements for plant hormones, abiotic stresses, and transcription factor binding sites, which is supported by the distinct transcriptional expression patterns of PdeCRCKs under abscisic acid (ABA), polyethylene glycol (PEG), and mannitol treatments. A transient overexpression of PdeCRCK3/5/6 in tobacco (Nicotiana benthamiana) leaves indicated their involvement in reactive oxygen species (ROS) scavenging, polyamine gene synthesis, and ABA signaling pathway modulation. Immunoprecipitation–Mass Spectrometry (IP–MS) and a yeast two-hybrid (Y2H) assay showed that PdeCRCK6 interacted with AAA-type ATPase proteins and ubiquitin, suggesting its potential function in being involved in chloroplast homeostasis and the 26S ubiquitin protease system. Taken together, these findings offer a comprehensive analysis of the RLCK-IV subfamily members in P. deltoides, especially laying a foundation for revealing the potential mechanism of PdeCRCK6 in response to osmotic stresses and accelerating the molecular design breeding of drought tolerance in poplar. Full article

Cronobacter sakazakii, an opportunistic foodborne pathogen, has a strong resistance to osmotic stress and desiccation stress, but the current studies cannot elucidate this resistance mechanism absolutely. A mechanosensitive channel MscM was suspected of involving to desiccation resistance mechanism of C. sakazakii. To investigate the specific molecular mechanism, the mscM mutant strain (ΔmscM) was constructed using the homologous recombination method, and the cpmscM complementary strain was obtained by gene complementation, followed by the analysis of the difference between the wild-type (WT), mutant, and complementary strains. Compared to the wild-type bacteria (WT), the inactivation rate of the ΔmscM strain decreased by 15.83% (p < 0.01) after desiccation stress. The absence of the mscM gene led to an increase in the membrane permeability of mutant strains. Through turbidity assay, it was found that the intracellular content of potassium ion (K⁺) of the ΔmscM strain increased by 2.2-fold (p < 0.05) compared to the WT strain, while other metal ion contents, including sodium ion (Na⁺), calcium ion (Ca²⁺), and magnesium ion (Mg²⁺), decreased by 48.45% (p < 0.001), 24.29% (p < 0.001), and 26.11% (p < 0.0001), respectively. These findings indicate that the MscM channel primarily regulates cell membrane permeability by controlling K⁺ efflux to maintain the homeostasis of intracellular osmotic pressure and affect the desiccation tolerance of bacteria. Additionally, the deletion of the mscM gene did not affect bacterial growth and motility but impaired surface hydrophobicity (reduced 20.52% compared to the WT strain, p < 0.001), adhesion/invasion capability (reduced 26.03% compared to the WT strain, p < 0.001), and biofilm formation ability (reduced 30.19% compared to the WT strain, p < 0.05) of the bacteria. This study provides a reference for the role of the mscM gene in the desiccation resistance and biofilm formation of C. sakazakii. Full article

Bone marrow mesenchymal stem cells (BM-MSCs) play a crucial role in bone formation through their ability to differentiate into osteoblasts. Aging, however, detrimentally affects the differentiation and proliferation capacities of BM-MSCs, consequently impairing bone regeneration. Thus, mitigating the aging effects on BM-MSCs is vital for addressing bone-related pathologies. In this study, we demonstrate that extracellular nanovesicles isolated from gold kiwi (GK-NVs) protect human BM-MSCs from ultraviolet (UV)-induced photoaging, thereby alleviating aging-related impairments in cellular functions that are crucial for bone homeostasis. Notably, GK-NVs were efficiently taken up by BM-MSCs without causing cytotoxicity. GK-NVs reduced intracellular reactive oxygen species (ROS) levels upon UV irradiation, restoring impaired proliferation and migration capabilities. Furthermore, GK-NVs corrected the skewed differentiation capacities of UV-irradiated BM-MSCs by enhancing osteoblast differentiation, as evidenced by the increased expression in osteoblast-specific genes and the calcium deposition, and by reducing adipocyte differentiation, as indicated by the decreased lipid droplet formation. These findings position GK-NVs as a promising biomaterial for the treatment of bone-related diseases such as osteoporosis. Full article

p66Shc is an adaptor protein and one of the cellular fate regulators since it modulates mitogenic signaling pathways, mitochondrial function, and reactive oxygen species (ROS) production. p66Shc is localized mostly in the cytosol and endoplasmic reticulum (ER); however, under oxidative stress, p66Shc is post-translationally modified and relocates to mitochondria. p66Shc was found in the intermembrane space, where it interacts with cytochrome c, contributing to the hydrogen peroxide generation by the mitochondrial respiratory chain. Our previous studies suggested that p66Shc is localized also in mitochondria-associated membranes (MAM). MAM fraction consists of mitochondria and mostly ER membranes. Contact sites between ER and mitochondria host proteins involved in multiple processes including calcium homeostasis, apoptosis, and autophagy regulation. Thus, p66Shc in MAM could participate in processes related to cell fate determination. Due to reports on various and conditional p66Shc intracellular localization, in the present paper, we describe the allocation of p66Shc pools in different subcellular compartments in mouse liver tissue and HepG2 cell culture. We provide additional evidence for p66Shc localization in MAM. In the present study, we use precisely purified subcellular fraction isolated by differential centrifugation-based protocol from control mouse liver tissue and HepG2 cells and from cells treated with hydrogen peroxide to promote mitochondrial p66Shc translocation. We performed controlled digestion of crude mitochondrial fraction, in which the degradation patterns of p66Shc and MAM fraction marker proteins were comparable. Moreover, we assessed the distribution of the individual ShcA isoforms (p46Shc, p52Shc, and p66Shc) in the subcellular fractions and their contribution to the total ShcA in control mice livers and HepG2 cells. In conclusion, we showed that a substantial pool of p66Shc protein resides in MAM in control conditions and after oxidative stress induction. Full article

Background: Hypophosphatemia is a known side-effect of parenteral iron administration, especially after intravenous ferric carboxymaltose (FCM). Fibroblast growth factor 23 (FGF23) is thought to play an important role in the pathophysiology of serum phosphate homeostasis. This study aimed to investigate the effects of FCM on FGF23 serum levels in FCM-treated pediatric patients with iron deficiency (ID)/iron deficiency anemia (IDA) caused by gastrointestinal diseases. Methods: Over 30 months, FGF23 serum levels were assessed prospectively in children with ID/IDA due to gastrointestinal diseases and treated with FCM infusion. Serum levels of intact FGF23 (iFGF23) were assessed and correlated to phosphate serum levels and factors of bone metabolism. Blood sampling was performed in three phases: before FCM infusion, 7–10 days after FCM infusion, and 6–8 weeks after FCM infusion. Results: A total of 42 FCM infusions were given to 35 children (20 girls) with a mean age (±SD) of 12.2 (±4.03) years (range: 2–16 years). The median levels of iFGF23 did not show a significant difference across the three phases (p = 0.56). No significant correlation was found between iFGF23 levels and 25-hydroxyvitamin D/parathyroid hormone/serum phosphate/serum calcium/alkaline phosphatase. No significant change was noted between pre- and post-treatment serum phosphate levels. However, four children (11.42%) developed asymptomatic and transient hypophosphatemia. Conclusions: No significant difference was found between pre-and post-FCM infusion serum iFGF23 levels and bone metabolism parameters. An increase of iFGF23 serum levels 7–10 days after FCM infusion was noted in patients with hypophosphatemia. Full article

Background. Critical and progressive cachexia may be observed in numerous medical disciplines, but in patients with various diseases, several pathways overlap (endocrine, inflammatory and kidney diseases, heart failure, cancer). Methods. Unlike numerous cohort studies that examine thyroid cancer and risk factors, a different method was used to avoid bias and analyze the sequence of events, i.e., the pathway. A case-control analysis is presented on patients with initial immune-mediated thyroiditis complicated by cachexia, presenting pulmonary pathology coexisting with opportunistic infection, and ultimately diagnosed with cancer (TC—thyroid cancer, misdiagnosed as lung cancer). Results. Contrary to other patients with lung cancer, the presented patients were not active smokers and exclusively women who developed cachexia with existing autoimmune processes in the first phase. Furthermore, the coexistence of short overall survival without cancer progression in the most seriously ill patients, as well as correlation with sex (contrary to history of smoking) and predisposition to mycobacterial disease, are very suggestive. Although we describe three different autoimmune conditions (de Quervain’s, Graves’, and atrophic thyroiditis), disturbances in calcium and metabolic homeostasis, under the influence of hormonal and inflammatory changes, are crucial factors of cachexia and prognosis. Conclusions. The unique sequence sheds light on immune-mediated thyroid disease as a subclinical paraneoplastic process modified by various therapeutic regimens. However, it is also associated with cachexia, systemic consequences, and atypical sequelae, which require a holistic approach. The differential diagnosis of severe cachexia, adenocarcinoma with pulmonary localization, and tuberculosis reactivation requires an analysis of immunological and genetic backgrounds. Contrary to highly specialized teams (e.g., lung cancer units), immunotherapy and general medicine in aging populations require a multidisciplinary, holistic, and inquiring approach. The lack of differentiation, confusing biases, and discrepancies in the literature are the main obstacles to statistical research, limiting findings to correlations of common factors only. Time-lapse case studies such as this one may be among the first to build evidence of a pathway and an association between inflammatory and endocrine imbalances in cancer cachexia. Full article

Recombinant aequorin has been extensively used in mammalian and plant systems as a powerful tool for calcium monitoring. While aequorin has also been widely applied in yeast research, a notable gap exists in the literature regarding comprehensive reviews of these applications. This review aims to address that gap by providing an overview of how aequorin has been used to explore calcium homeostasis, signaling pathways, and responses to stressors, heavy metals, and toxic compounds in Saccharomyces cerevisiae. We also discuss strategies for further developing the aequorin system in yeast, with particular emphasis on its use as a model for human calcium signaling studies, such as the reproduction of the mitochondrial calcium uniporter. By highlighting previous research and pinpointing potential future applications, we discuss the untapped potential of aequorin in yeast for drug screening, environmental toxicity testing, and disease-related studies. Full article

An ellagitannin-derived metabolite, Urolithin A (UA), has emerged as a potential therapeutic agent for metabolic disorders due to its antioxidant, anti-inflammatory, and mitochondrial function-improving properties, but its efficacy in protecting against ER stress remains underexplored. The endoplasmic reticulum (ER) is a cellular organelle involved in protein folding, lipid synthesis, and calcium regulation. Perturbations in these functions can lead to ER stress, which contributes to the development and progression of metabolic disorders such as metabolic-associated fatty liver disease (MAFLD). In this study, we identified a novel target protein of UA and elucidated its mechanism for alleviating palmitic acid (PA)-induced ER stress. Cellular thermal shift assay (CETSA)-LC-MS/MS analysis revealed that UA binds directly to the sarcoplasmic/endoplasmic reticulum Ca²⁺-ATPase (SERCA), an important regulator of calcium homeostasis in mitochondria-associated ER membranes (MAMs). As an agonist of SERCA, UA attenuates abnormal calcium fluctuations and ER stress in PA-treated liver cells, thereby contributing to cell survival. The lack of UA activity in SERCA knockdown cells suggests that UA regulates cellular homeostasis through its interaction with SERCA. Collectively, our results demonstrate that UA protects against PA-induced ER stress and enhances cell survival by regulating calcium homeostasis in MAMs through SERCA. This study highlights the potential of UA as a therapeutic agent for metabolic disorders associated with ER stress. Full article