Search Results (209)

Store-operated calcium entry (SOCE), mediated by the endoplasmic reticulum (ER) Ca²⁺ sensors stromal interaction molecule (STIM) proteins and the plasma membrane (PM) Orai channels, is essential for calcium signaling and a wide range of physiological processes. Precise regulation of SOCE is critical for maintaining tissue homeostasis, whereas its dysregulation contributes to diverse pathological conditions, particularly organ fibrosis. In this review, we outline the molecular basis of SOCE and discuss how its dysregulation is implicated in human disease. We further emphasize the pivotal role of SOCE in driving fibrotic progression across major organ systems. Finally, we summarize current therapeutic strategies targeting SOCE and highlight their potential for the treatment of fibrosis. Full article

Store-operated Calcium (Ca²⁺) entry (SOCE), mediated by stromal interaction molecule 1 (STIM1) and Orai1, is a central pathway controlling intracellular Ca²⁺ homeostasis. Gain-of-function (GoF) mutations in STIM1 cause a spectrum of clinically overlapping disorders historically classified as Stormorken Syndrome (STK), tubular aggregate myopathy (TAM), and York Platelet Syndrome (YPS). However, increasing evidence indicates that these entities could represent a shared disease spectrum rather than distinct conditions. At the molecular level, STIM1 activation is governed by a series of autoinhibitory checkpoints that maintain the protein in a tightly controlled resting state. GoF mutations disrupt these regulatory constraints, leading to dysregulated SOCE activity that is frequently, but not uniformly, associated with constitutive channel activation depending on the specific mutation and cellular context. While many disease-associated variants localize to the EF hand, a highly conserved helix–loop–helix Ca²⁺ binding motif, and the CC1 (coiled-coil 1) domain involved in molecular regulation of STIM1 activation, an increasing number of mutations in the C-terminal region further expands the mechanistic and clinical spectrum. In this review, we summarize current concepts of molecular STIM1 activation and discuss how distinct mutations perturb specific regulatory elements of the protein. By systematically integrating published case reports into a comprehensive overview, including a mutation–phenotype correlation table, we highlight the remarkable variability in and incomplete penetrance of clinical manifestations. Full article

Background/Objectives: Integrating heterogeneous One Health time series into transparent and usable surveillance workflows remains difficult because data preparation, modeling, and interpretation are often separated across tools. In this paper, we introduce OH-MEMA (One Health Mixed-Effects Modeling and Analytics), an interactive visual analytics framework that integrates heterogeneous One Health data streams, including human clinical outcomes, environmental factors, and wastewater surveillance data, to support syndromic surveillance and pandemic preparedness. Methods: The system enables users to upload and analyze multi-source datasets through an interactive web-based interface. The modeling component supports fixed effects for multi-source predictors, random effects for spatial, temporal, and demographic grouping variables, optional random slopes, and rolling time-series validation. Model results are visualized as time series comparing observed and predicted outcomes, with evaluation metrics including Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and correlation. To support iterative exploration, the system incorporates analytic provenance through a visual model tree that records prior configurations. Results: OH-MEMA was validated through both quantitative and qualitative evaluations. Quantitatively, mixed-effects models were assessed across multiple counties and outcomes using RMSE, MAE, and correlation, demonstrating robust predictive performance. Qualitatively, expert users, including epidemiologists and disease surveillance analysts, evaluated the system using the NASA Task Load Index and open-ended interviews, indicating improved interpretability, manageable cognitive workload, and effective workflow integration. Conclusions: OH-MEMA provides an interpretable, human-in-the-loop platform for exploratory forecasting and comparative model analysis in syndromic surveillance. The framework effectively bridges data integration, modeling, and interpretation, supporting user-centered analytical reasoning and decision-making in One Health applications. Full article

Although LRRK2 mutations modulate systemic glucose homeostasis and metabolic dysfunction precedes Parkinson’s disease (PD) motor symptoms; the way in which pathogenic variants of LRRK2 disrupt astrocytic glucose metabolism and organellar homeostasis remains poorly understood. Here, we demonstrate that LRRK2-I1371V mutation causes profound metabolic and organellar dysfunction in LRRK2-I1371V PD-iPSC-derived astrocytes and U87 cells overexpressing I1371V variant. LRRK2-I1371V astrocytes exhibit significantly reduced GLUT1 expression and cell surface localization, resulting in impaired glucose uptake and decreased lactate production. This metabolic insufficiency correlates with cascading mitochondrial dysfunction, characterized by membrane depolarization, elevated reactive oxygen species, enhanced ubiquitination and reduced proteasomal activity. Reduced LAMP1/LAMP2 expression, impaired lysosomal acidification, and selective cathepsin D deficiency were observed. Accumulation of undegraded cargo was confirmed by transmission electron microscopy upon α-synuclein exposure. ER stress was evident by upregulation of GADD34/CHOP, increased phospho-PERK, and reduced nascent protein synthesis. Increased ER–mitochondrial contact via MAMs and enhanced STIM1-ORAI3 clustering reflect compensatory but ultimately insufficient responses to energy stress. Our results reveal that LRRK2-I1371V induces glucose uptake deficits, leading to energy depletion and integrated ER–mitochondria–lysosome dysfunction, thus indicating restoration of astrocytic metabolic capacity as a potential therapeutic strategy for LRRK2-associated PD. Full article

Tubular aggregate myopathy (TAM) is a rare inherited muscle disorder characterized by the abnormal accumulation of tubular aggregates (TAs) within skeletal muscle fibers. These aggregates, composed of compacted sarcoplasmic reticulum (SR) tubules, are strongly linked to disturbances in calcium (Ca²⁺) homeostasis. Clinically, TAM manifests with slowly progressive proximal muscle weakness, exercise intolerance, cramps, and myalgia, frequently beginning in childhood and often present with elevated serum creatine kinase levels. These symptoms can also be associated with some additional disorders, such as thrombocytopathy, miosis, hypocalcemia, hyposplenism, and ichthyosis, thereby resulting in a clinical picture that overlaps with symptoms of Stormorken (STRMK) syndrome. Considerable heterogeneity exists in age of onset, severity, and extra-muscular involvement, suggesting that TAM and STRMK represent a continuum rather than distinct entities. Histopathological hallmarks include TAs staining positive for SR proteins and displaying a honeycomb-like ultrastructure, consistent with aberrant SR remodeling. Mutations in genes encoding key regulators of store-operated calcium entry (SOCE), including STIM1 and ORAI1 have been identified as major contributors to TAM and its broader clinical spectrum, which encompasses STRMK syndrome, whereas mutations in CASQ1 and RYR1, have been described in only a minority of patients. Despite advances in delineating the genetic and molecular basis of TAM, key questions remain regarding the mechanisms that drive TAs formation and translate Ca²⁺ dysregulation into muscle dysfunction and multisystem disease. Understanding the molecular mechanisms underlying TAM and STRMK syndrome is crucial for developing targeted therapies. Moreover, further research is needed to elucidate additional pathways involved in disease progression and to refine genotype–phenotype correlations. This review summarizes current knowledge on the genetics, pathophysiology, clinical features, and diagnostic hallmarks of TAM, with particular emphasis on the role of Ca²⁺ homeostasis. Full article

Neuronal function relies on the precise coordination between intracellular calcium (Ca²⁺) signaling and the cytoskeletal architecture that underpins synaptic transmission, plasticity, and structural stability. Disruption of this calcium–cytoskeleton interplay has been noted in numerous neurodegenerative diseases. We discuss how Ca²⁺-dependent cytoskeletal remodeling governs long-term potentiation and depression, dendritic spine morphology, and presynaptic function, highlighting the functions of end-binding proteins, STIM (Stromal Interaction Molecule)/Orai-mediated store-operated calcium entry, and the spine apparatus. Disease-specific manifestations of cytoskeletal–calcium dysregulation are reviewed across Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, tauopathies, and prion disorders. Finally, we evaluate emerging therapeutic strategies targeting calcium homeostasis, cytoskeletal dynamics, and their downstream effectors, including multi-target approaches. Full article

Background: Tubular aggregate myopathy (TAM) is an autosomal dominant myopathy that results from gain-of-function mutations in the STIM1 and ORAI1 genes, which encode the two key proteins that coordinate store-operated Ca²⁺ entry in skeletal muscle and other cell types. Knock-in mice heterozygous for a glycine-to-serine point mutation in the ORAI1 pore (ORAI1^G100S/+ or GS mice) phenocopy several key aspects of TAM in humans with the analogous mutation including muscle weakness, exercise intolerance, elevated CK levels, hypocalcemia, and the presence of tubular aggregates. Methods: Since homozygous inheritance of the ORAI1-G100S mutation is embryonic lethal, we assessed the impact of homotypic ORAI1-G100S expression in skeletal muscle by crossing GS mice with constitutive, muscle-specific ORAI1 knock-in mice (cORAI1-KO). Results: Compound cORAI1-KO/GS mice exhibit only one active ORAI1 (GS) allele, and thus only express ORAI1-G100S monomers in skeletal muscle (‘homotypic’ GS mice). Homotypic GS mice exhibit an earlier onset and more severe muscle phenotype than age-matched heterotypic GS mice with both WT and GS alleles. Specifically, homotypic GS mice exhibit TAs at an earlier age, as well as significantly reduced in vivo muscle performance (grip strength, treadmill endurance, and rotarod endurance), maximal specific force production, and respiratory function, compared to those observed for both WT and heterotypic GS mice. Conclusions: These findings indicate that homotypic expression of the ORAI1-G100S mutation in skeletal muscle results in an earlier-onset and more severe muscle phenotype. Full article

Background: Streptococcus pneumonia is the primary etiological agent of community-acquired pneumonia (CAP). Pneumococci promote severe lung injury through the release of virulence factors, including pneumolysin (PLY). Obesity/diabetes increases pneumonia-associated mortality, but the mechanisms remain elusive. We found that obese db/db mice have increased pulmonary barrier disruption to PLY. Previously we showed that upregulation of NOX1 in endothelial cells (EC) of db/db mice drives endothelial dysfunction, but a role for NOX1 in PLY-induced lung injury, especially in diabetic conditions, has not yet been described. Results: Increased NOX1 in lung ECs dose-dependently increased superoxide and EC barrier disruption (p < 0.05). Even at low activity levels, NOX1 greatly potentiated PLY-induced EC barrier disruption, whereas loss of NOX1 activity, either pharmacological or genetic, reduced barrier disruption (p < 0.05). Blockade of calcium entry protected the EC barrier from combined PLY and NOX1, indicating a key role for calcium. Hyperglycemia amplified PLY-enduced EC barrier disruption and intracellular calcium and these effects were mitigated by NOX1 inhibition and silencing (p < 0.05). NOX1-enhanced calcium entry was reduced by knockout of calcium sensor STIM1, and PLY-induced barrier disruption was reduced by STIM1 inhibition. Levels of STIM1, Orai1, TRPV4, or TRPC4 were unchanged by HG, but TRPC1 significantly increased (p < 0.05). NOX1 and HG promoted increased STIM1 and TRPC1 binding, and silencing TRPC1 ameliorated PLY-induced barrier disruption (p < 0.05). Increased calcium promoted mitochondrial permeability transition pore (MPTP) opening and PPIF inhibition protected EC barrier function (p < 0.05). Conclusions: These results suggest that elevated glucose levels in obesity primes EC barrier disruption by amplifying PLY-induced calcium influx via a novel NOX1, STIM1, TRPC1 and MPTP signaling axis. Full article

Post-inflammatory hyperpigmentation (PIH) is a common pigmentary disorder characterized by excessive melanin production following skin inflammation. Histamine, a key inflammatory mediator, is known to stimulate melanogenesis via H₂ receptors; however, the underlying calcium (Ca²⁺) signaling mechanisms remain largely unexplored. In this study, we investigated the role of the ORAI1-STIM1 complex in histamine-induced melanogenesis using B16F10 melanoma cells and normal human epidermal melanocytes (NHEMs). Histamine (10–30 μM) significantly increased melanin content (2.5–2.8-fold), an effect specifically abolished by the H₂ antagonist famotidine. Notably, while acute histamine application failed to trigger immediate Ca²⁺ influx, chronic exposure significantly enhanced store-operated Ca²⁺ entry (SOCE) capacity by approximately 2.8-fold, providing evidence for a functional remodeling of the Ca²⁺ signaling machinery. Histamine-induced melanogenesis was significantly suppressed by intracellular Ca²⁺ chelation, pharmacological inhibition of ORAI1 (BTP-2 or Synta-66), and siRNA-mediated silencing of ORAI1 or STIM1, but not ORAI2, ORAI3, or STIM2. Our findings demonstrate that chronic histamine exposure drives hyperpigmentation through ORAI1-STIM1-mediated SOCE remodeling, establishing this complex as a promising therapeutic target for the treatment of PIH and related inflammatory pigmentary disorders. Full article

Salivary glands produce saliva through precisely coordinated epithelial ion transport processes. Ion channels are essential components of the molecular machinery that convert neural and hormonal signals into targeted ion and water flux. This review focuses on the integrated molecular and cellular mechanisms by which ion channels cooperate to generate salivary fluid under physiological conditions. Saliva formation proceeds through two sequential stages: isotonic primary fluid secretion by acinar cells, followed by ionic modification within the ductal epithelium. Parasympathetic stimulation activates muscarinic M1/3 receptors, initiating intracellular calcium signaling through inositol 1,4,5-trisphosphate-dependent release from the endoplasmic reticulum and sustained calcium entry via Orai1/TRPC channels. Elevated cytosolic calcium activates apical ANO1/TMEM16A chloride channels, the rate-limiting step in acinar fluid secretion, together with basolateral calcium-activated potassium channels that preserve the electrochemical driving force for chloride efflux. Chloride accumulation is maintained by Na⁺/K⁺-ATPase and the Na⁺-K⁺-2Cl⁻ cotransporter, while osmotic gradients drive water movement through apical aquaporin-5 and basolateral aquaporin-1/3. As primary saliva traverses the ductal system, epithelial sodium channels, CFTR, and additional ion transport pathways reabsorb sodium and chloride and secrete potassium and bicarbonate, producing hypotonic final saliva. By synthesizing calcium signaling, chloride and potassium conductance, sodium handling, and epithelial polarity into a unified framework, this review establishes ion channel integration as the fundamental basis of salivary gland fluid secretion. Full article

A growing body of work has linked the dysregulation of transmembrane (TMEM) proteins to the proliferation, metastasis, drug resistance, and tumor microenvironment remodeling of lung cancer, the leading global cause of cancer mortality. Renamed members such as STING1 (stimulator of interferon response cGAMP interactor 1, TMEM173), ANO1 (anoctamin-1, TMEM16A), ORAI1 (ORAI calcium release-activated calcium modulator 1, TMEM142A), ORAI3 (TMEM142C), and NDC1 (NDC1 transmembrane nucleoporin, TMEM48) are among the most extensively studied ones. Mechanisms of TMEM dysregulation in lung cancer span the modulation of Ca²⁺ influx, lysosomal exocytosis, ferroptosis, Wnt and β-catenin signaling, and immune cell infiltration and immune checkpoint rewiring, among others. Epigenetic silencing and targetable fusions (i.e., TMEM106B-ROS1 and TMEM87A-RASGRF1) create DNA-level vulnerabilities, while miRNA sponges offer RNA-level druggability. A subset of studies revealed context-specific expression (endothelial, B cell, and hypoxic EV) that can be exploited to remodel the tumor microenvironment. One study specifically focused on how isoform-specific expression and localization of TMEM88 determine its functional impact on tumor progression. Yet for most TMEMs, only pre-clinical or early-phase data exist, with many supported by a single study lacking independent validation. This review brings together scattered evidence on TMEM proteins in lung cancer, with the aim of guiding future work on their possible use as biomarkers or therapeutic targets. Full article

Calcium ions (Ca²⁺) serve as universal second messengers regulating endocrine, neuronal, and metabolic processes. In children and adolescents, tight calcium signaling control is crucial for growth, hormone homeostasis, neuromuscular function, and neurodevelopment. Disruptions in Ca²⁺-dependent pathways—whether genetic, metabolic, or acquired—underlie a spectrum of pediatric endocrine diseases often presenting with neurological manifestations This review summarizes calcium’s roles in hormone secretion, parathyroid and vitamin D metabolism, and neuronal excitability, and discusses monogenic and metabolic disorders affecting calcium sensing and signaling, including CASR, GNA11, AP2S1, STIM1, and ORAI1 mutations. Diagnostic challenges, therapeutic strategies, and future directions for precision medicine in pediatric neuroendocrinology are highlighted, emphasizing early recognition and improved clinical outcomes. Full article

Store-operated Ca²⁺ entry (SOCE) is a key regulator of cytosolic Ca²⁺ (Ca²⁺_cyt). Presynaptic SOCE can be activated by ligands like α-latrotoxin, which acts through the presynaptic G-protein-coupled receptor latrophilin-1 (LPHN1), inducing Ca²⁺ influx and neurotransmitter release. To understand how SOCE-associated proteins contribute to LPHN1 signaling in neurons, we used mouse neuroblastoma NB2a cells as a genetically tractable neuronal model. The cells were stably transfected with exogenous LPHN1 or its non-signaling mutant and stimulated with the non-pore-forming α-latrotoxin mutant LTX^N4C, a known trigger of neurotransmitter release. LPHN1 expression increased the proportion of neuron-like cells and upregulated the voltage-gated Ca²⁺ channels Ca_v1.2 and Ca_v2.1. LPHN1 stimulation by LTX^N4C induced a small Ca²⁺ release sensitive to thapsigargin, and a strong, gradual influx of Ca²⁺, which was insensitive to thapsigargin. Single-cell imaging revealed that this influx consisted of desynchronized high-amplitude Ca²⁺ oscillations in individual cells. This response was reduced by Orai2 knockdown and completely blocked by the Ca_v2.1/2.2 inhibitor ω-conotoxin MVIIC. We conclude that LPHN1 activation by LTX^N4C primes Ca²⁺ stores and induces the opening of Ca_v2.1/2.2 channels. These channels mediate an initial Ca²⁺ influx that triggers Ca²⁺-induced Ca²⁺ release and SOCE. This mechanism, elucidated in model cells, can explain how LTX^N4C stimulates neurotransmitter release. Full article

STC2 (stanniocalcin 2) controls calcium (Ca²⁺) homeostasis in human platelets and other cell lines. The regulation of intracellular Ca²⁺ homeostasis is crucial for platelet activation; thus, the alteration in intracellular Ca²⁺ concentration or the mechanism involved in its regulation has been proposed to underlie some thrombotic disorders. Our previous studies evidenced that the knockdown of STC2 altered murine platelet activation; furthermore, a reduction in STC2 expression resulted in enhanced Ca²⁺ homeostasis in diabetic patients and, therefore, would contribute to the prothrombotic condition as a hallmark of diabetes mellitus type 2 (DM2). In this study, we examine a possible link between the expression of stanniocalcins (STCs) and different thrombotic events in humans. The expression of STCs was determined by Western blotting (WB); meanwhile, the analysis of protein interaction and phosphorylation was performed by completing a previous immunoprecipitation protocol (IP) of the proteins of interest. Thus, our results from patients with stroke/ictus presented a clear reduction in STC2 expression in their platelets, finding less STC2 content in the youngest thrombotic patients. Furthermore, acetyl-salicylic acid (ASA) administration reversed the decrease in the expression of STC2 in patients who did not suffer additional thrombotic episodes, as evidenced by the longitudinal analysis of up to 10 years of follow-up. Additionally, the increase in STC2 phosphorylation at the serine residues revealed increased activity of STC2 in thrombotic patients. Finally, we suggest that store-operated Ca²⁺ entry (SOCE) is over-activated in patients suffering from stroke/ictus, as revealed by the increase in the STIM1/Orai1 interaction found under resting conditions and, further, because MEG-01 cells transfected with siRNA STC2 to evoke artificial reduction in the STC2 expression presented an increased SOCE with respect to the control cells transfected with siRNA A. Conversely, the expression of the non-capacitative Ca²⁺ channels, Orai3 and TRPC6, was found to be reduced in patients with stroke. Altogether, our data allow us to conclude that STC2 represents a promising marker of stroke/ictus in thrombotic patients. Full article

Background: This case report describes a calf that underwent castration at a Japanese livestock farm and subsequently died after developing clinical signs of tetanus, including muscle rigidity and difficulty standing. Methods: A postmortem examination was performed, focusing on indurated lesions at the castration site, which were subjected to bacteriological and genetic analyses. Results: Clostridium tetani strain OPLHC-2022-Y645 was isolated from the purulent lesion. Whole-genome sequencing revealed a close genetic relationship to strain KHSU-254310-026, which belongs to the high toxin-producing lineage Clade 1-3 previously reported in Japan. Immunoassays demonstrated that OPLHC-2022-Y645 exhibited the highest tetanus toxin production among isolates tested to date. Conclusions: Whole-genome sequencing and immunoassay findings suggest that the rapid progression of tetanus in this calf could be associated with the strong toxin-producing capacity of the OPLHC-2022-Y645 strain. Full article