Search Results (275)

The Rift Valley fever virus (RVFV) is a highly pathogenic, mosquito-borne zoonotic virus that poses a significant risk to livestock, human health, and global public health security. Although RVFV is classified by the World Health Organization (WHO) as a priority pathogen with epidemic potential, no licensed vaccines or effective antiviral therapies are currently available. A limited understanding of the molecular mechanisms of RVFV entry has hindered therapeutic development. Here, we elucidate the molecular basis by which the RVFV envelope glycoprotein Gn recognizes its receptor, low-density lipoprotein receptor-related protein 1 (LRP1). Bio-layer interferometry (BLI) demonstrates that full-length LRP1 directly binds the head domain of Gn with nanomolar affinity in a Ca²⁺-dependent manner. Both LRP1 clusters II (CL II) and IV (CL IV) independently interact with Gn, with CL IV exhibiting stronger affinity, indicating a multivalent recognition mode. Structural modeling using AlphaFold 3 reveals pronounced charge complementarity between basic residues on Gn and acidic, Ca²⁺-coordinated pockets within LRP1. Mutations in key acidic residues in CL IV greatly reduced Gn binding, confirming the essential roles of Ca²⁺ coordination and electrostatic interactions. Collectively, our findings define a Ca²⁺-stabilized, electrostatically driven mechanism for RVFV Gn recognition by LRP1, providing molecular insight into viral entry and a structural framework for the rational design of vaccines and antiviral therapeutics. Full article

Centro Español de Metrología (CEM) is developing a quantum frequency standard based on trapped calcium ions, marking its entry into the landscape of the second quantum revolution. Optical frequency standards offer unprecedented precision by referencing atomic transitions that are fundamentally stable and immune to environmental drift. However, the challenge of developing such a system from scratch is unaffordable for a medium-sized National Metrology Institute (NMI), which seems to limit the ability of an institute such as CEM to contribute to this field of research. To overcome this, CEM has adopted a hybrid strategy, combining commercially available components with custom integration to accelerate deployment. This paper defines and implements an architecture adapted to the constraints of a medium-size NMI, where the main contribution is the systematic design, selection, and interconnection of the subsystems required to realize this standard. The rationale behind the system design is presented, detailing the integration of key elements for ion trapping, laser stabilization, frequency measurement, and system control. Current progress, ongoing developments, and future research directions are outlined, establishing the foundation for spectroscopic measurements and uncertainty evaluation. The project represents a strategic step toward strengthening national capabilities in quantum metrology for a medium-sized NMI. Full article

Membrane distillation (MD) is a promising technology for reducing the volume of high-salinity brines generated from desalination plants, yet limited knowledge exists regarding its fouling behavior under long-term operation. In this study, fouling was investigated through the autopsy of a hollow fiber MD module operated for 120 days in a direct contact membrane distillation (DCMD) configuration using real desalination brine. Despite stable salt rejection exceeding 99%, a gradual decline in flux and permeability was observed, indicating progressive fouling and partial wetting. Post-operation analyses, including SEM, EDS, ICP-OES, and FT-IR, revealed that the dominant foulants were inorganic scales, particularly calcium carbonate (CaCO₃), with minor contributions from suspended particles (SiO₂, Fe) and organic matter. Fouling was more severe in the inlet and inner regions of the module due to intensified temperature and concentration polarization, which promoted supersaturation and scale deposition. These combined effects led to a reduction in membrane hydrophobicity and liquid entry pressure, ultimately accelerating partial wetting and performance deterioration. The findings provide valuable insights into the spatial fouling behavior and mechanisms in MD systems, highlighting the importance of hydrodynamic optimization and fouling mitigation strategies for long-term brine concentration applications. 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

Furin, a calcium-dependent serine endoprotease of the proprotein convertase family, plays a pivotal role in both physiological homeostasis and viral pathogenesis. By cleaving polybasic motifs within viral glycoproteins, furin enables the maturation of structural proteins essential for viral entry, fusion, and replication. This mechanism has been documented across a broad spectrum of human pathogens, including SARS-CoV-2, influenza virus, human immunodeficiency virus, human papilloma virus, hepatitis B virus, flaviviruses, herpesviruses, and paramyxoviruses, highlighting furin as a conserved molecular hub in host–virus interactions. Genetic variability within the FURIN gene further modulates infection outcomes. Several single-nucleotide polymorphisms (SNPs), such as rs6226 and rs1981458, are associated with altered COVID-19 severity, whereas variants like rs17514846 confer protection against human papilloma virus infection. Conversely, mutations predicted to reduce enzymatic activity have been linked to attenuated SARS-CoV-2 pathogenesis in certain populations. These findings underscore the importance of considering population genetics when evaluating viral susceptibility and disease progression. Despite advances, unresolved questions remain regarding furin’s non-canonical roles in viral life cycles, tissue-specific regulation, and interactions with other host proteases and immune modulators. Targeted inhibition of furin and related convertases represents a promising avenue for broad-spectrum antiviral interventions. Collectively, current evidence positions furin as a central node at the intersection of viral pathogenesis, host genetic variability, and translational therapeutic potential. Full article

Endometrial cancer is one of the most common malignancies of the female reproductive system, with incidence rising globally due to population ageing and life-style-related risk factors. Calcium (Ca²⁺) is a ubiquitous second messenger regulating diverse physiological processes, and its dysregulation has been increasingly implicated in carcinogenesis, including endometrial. Altered expression and function of Ca²⁺ channels, pumps, exchangers, and binding proteins disrupt the finely tuned balance of Ca²⁺ influx, efflux, and intracellular storage, leading to aberrant signalling that promotes tumour proliferation, migration, survival, and metastasis. This review summarises current knowledge on the molecular “Ca²⁺ toolkit” in the human uterus, highlighting the role of voltage-gated calcium channels (VGCCs), transient receptor potential (TRP) channels, store-operated calcium entry (SOCE) components, Na⁺/Ca²⁺ exchangers, purinergic receptors, P-type ATPases (SERCA, SPCA, PMCA), ryanodine (RyR) and inositol 1,4,5-trisphosphate (IP₃R) receptors, and mitochondrial Ca²⁺ uniporter (MCU) complexes in endometrial cancer progression. Multiple Ca²⁺-handling proteins, including CACNA1D, CACNA2D1, TRPV4, TRPV1, TRPM4, MCU, and RyR1, exhibit cancer-associated overexpression or functional changes, correlating with poor prognosis and aggressive disease features. Emerging evidence supports the therapeutic potential of targeting Ca²⁺ homeostasis using small-molecule inhibitors, ion channel modulators or gene-silencing strategies. These interventions may restore Ca²⁺ balance, induce apoptosis or autophagy, and suppress metastatic behaviour. While no clinical trials have yet explicitly focused on Ca²⁺ modulation in endometrial cancer, the diversity of dysregulated Ca²⁺ pathways offers a rich landscape for novel therapeutic strategies. Targeting key components of the Ca²⁺ signalling network holds promise for improving outcomes in endometrial cancer. 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

Feline calicivirus (FCV) is among the few members of the Caliciviridae family that can replicate efficiently in vitro. Our recent studies have found the Transferrin Receptor Protein (TFRC) is an entry receptor that facilitates the internalization of FCV. To explore the potential involvement of additional host factors in conjunction with TFRC during the viral entry process, we identified metabotropic glutamate receptor 2 (mGluR2) as a specific interacting partner for both TFRC and the FCV VP1 protein by Co-IP analysis. Our findings indicate that the downregulation of mGluR2, along with its downstream signaling molecule, Calcium-activated potassium channel subunit alpha-1 (KCa1.1), significantly inhibits FCV replication by impairing viral internalization. Importantly, the knockout of TFRC did not diminish the effects of mGluR2 and KCa1.1 on FCV infection. Furthermore, mGluR2 was found to interact directly with FCV VP1, rather than with TFRC, and the rate of F-actin polymerization induced by FCV infection was reduced solely by the downregulation of mGluR2 protein expression, not by TFRC knockout. These results suggest that mGluR2 may independently mediate FCV internalization, operating independently of TFRC, and plays a critical role in the formation of endocytic vesicles. Overall, the results indicate that multiple host factors, including TFRC and mGluR2, are involved in the internalization of FCV into host cells. Further research is necessary to explore the propagation of other caliciviruses, such as norovirus, in vitro. Full article

P2Y₂ receptors are a subclass of G protein-coupled receptors activated by the extracellular nucleotides ATP and UTP. These receptors are widely expressed in multiple tissues—including the brain, lungs, heart, and kidneys—and play pivotal roles in inflammation, wound healing, and cell migration. Through coupling with various G proteins, P2Y₂ receptors initiate diverse intracellular signaling pathways that mediate calcium mobilization, cytokine release, and cytoskeletal reorganization. Recent studies highlight their dual roles in health and disease. In physiological contexts, P2Y₂ receptors contribute to immune modulation and tissue repair. In pathological conditions, they are implicated in Alzheimer’s disease by promoting non-amyloidogenic processing of amyloid precursor protein and in dry eye disease by enhancing mucin secretion while modulating ocular inflammation. They also influence chloride secretion and mucosal hydration in cystic fibrosis and contribute to inflammatory regulation and epithelial repair in inflammatory bowel disease. Additionally, P2Y₂ receptors modulate breast cancer progression by regulating cell adhesion, migration, and matrix remodeling. Their involvement in blood pressure regulation via epithelial sodium channel modulation and their facilitative role in HIV-1 entry further underscore their clinical significance. These multifaceted functions position P2Y₂ receptors as promising therapeutic targets for diverse diseases, warranting further investigation for translational applications. Full article

Cadmium (Cd), a pervasive and highly phytotoxic metal pollutant, poses severe threats to agricultural productivity, ecosystem stability, and human health through its entry into the food chain. Plants have evolved intricate defense mechanisms, among which the strategic manipulation of nutrient elements emerges as a critical physiological and biochemical strategy for mitigating Cd stress. This comprehensive review delves deeply into the multifaceted roles of essential macronutrient elements (nitrogen, phosphorus, potassium, calcium, magnesium, sulfur), essential micronutrient elements (zinc, iron, manganese, copper) and non-essential beneficial elements (silicon, selenium) in modulating plant responses to Cd toxicity. We meticulously dissect the physiological, biochemical, and molecular underpinnings of how these nutrients influence Cd bioavailability in the rhizosphere, Cd uptake and translocation pathways, sequestration and compartmentalization within plant tissues, and the activation of antioxidant defense systems. Nutrient elements exert their influence through diverse mechanisms: competing with Cd for root uptake transporters, promoting the synthesis of complexes that reduce Cd mobility, stabilizing cell walls and plasma membranes to restrict apoplastic flow and symplastic influx, modulating redox homeostasis by enhancing antioxidant enzyme activities and non-enzymatic antioxidant pools, regulating signal transduction pathways, and influencing gene expression profiles related to metal transport, chelation, and detoxification. The complex interactions between nutrients themselves further shape the plant’s capacity to withstand Cd stress. Recent advances elucidating nutrient-mediated epigenetic regulation, microRNA involvement, and the role of nutrient-sensing signaling hubs in Cd responses are critically evaluated. Furthermore, we synthesize the practical implications of nutrient management strategies, including optimized fertilization regimes, selection of nutrient-efficient genotypes, and utilization of nutrient-enriched amendments, for enhancing phytoremediation efficiency and developing low-Cd-accumulating crops, thereby contributing to safer food production and environmental restoration in Cd-contaminated soils. The intricate interplay between plant nutritional status and Cd stress resilience underscores the necessity for a holistic, nutrient-centric approach in managing Cd toxicity in agroecosystems. Full article

Background/Objectives: This study investigates the pharmacological potential of 1,4-dihydropyridine derivatives, functionalized with an imidazo[2,1-b]thiazole scaffold, as selective modulators of intestinal motility. Given their structural similarity to both L-type calcium channel blockers and spasmolytics such as Otilonium Bromide (OB), we explored their repurposing for the treatment of gut motility disorders. Methods: A focused library of 83 1,4-dihydropyridine derivatives was screened for spasmolytic activity on potassium (80 mM)-induced depolarization in isolated guinea pig ileal and colonic tissues. Compounds showing pharmacodynamic profiles similar to OB and nifedipine were further evaluated for their effects on the spontaneous contractility of longitudinal and circular smooth muscle layers. Additional functional assays assessed intestinal transit, visceral nociception, and mixing/fragmentation efficiency. Microbiota safety was preliminarily tested on mixed cultures of Bifidobacterium and Lactobacillus species. Results: Compounds 62 and 65 selectively relaxed intestinal smooth muscle, primarily targeting the longitudinal layer without affecting vascular contractility. Ex vivo testing highlights that compounds 62 and 65 could both modulate gut transit and mixing without causing functional constipation or pain. Microbiota analyses showed no detrimental effects on “good” bacterial species Bifidobacterium and Lactobacillus spp. Conclusions: The favorable gastrointestinal and microbiological profiles of compounds 62 and 65, combined with their structural versatility, support their potential repurposing for functional bowel disorders. Their selective activity suggests a promising role in therapies targeting intestinal motility while preserving microbiota homeostasis, supporting the need for extended pharmacological characterization. Full article

Tubular aggregates (TAs), ordered arrays of sarcoplasmic reticulum (SR) tubes, are the main morphological alteration found in muscle biopsies from patients affected by TA myopathy (TAM). TAM has been linked to mutations in the genes encoding for STIM1 and ORAI1, which are two proteins that mediate Store-Operated Ca²⁺ entry (SOCE). SOCE is a mechanism that allows recovery of extracellular Ca²⁺ during fatigue, when the SR becomes depleted. As TAs also form in fast-twitch muscle fibers of aging male mice (not in females), we studied the effect of sex hormones on the aggregation of TAs during aging. We administered estrogen (ad libitum in drinking water) to male mice from 10 to 18 months of age and then evaluated the following: (a) the presence of TAs using histology and electron microscopy (EM); (b) oxidative stress, a mechanism that could underlie damage to proteins and membranes (and possibly their accumulation in TAs); and (c) SOCE function during ex vivo stimulation in the presence or absence of external Ca²⁺ or SOCE blocker (BTP-2). The results collected indicate that treatment with estrogen (a) significantly reduced the formation of TAs; (b) reduced oxidative stress, which was elevated in aging male mice; and (c) restored SOCE, i.e., the capability of aged EDL muscles to use external Ca²⁺ by promoting maintenance of Ca²⁺ Entry Units (CEUs, the intracellular junctions that mediate SOCE). Finally, we also show that formation of TAs is reduced by treatment of mice with N-acetilcysteine (NAC), a potent antioxidant also administered ad libitum in drinking water. Full article

Benign prostate hyperplasia (BPH) is characterized by prostate enlargement and dynamic alterations contributing to development of lower tract urinary symptoms (LUTS). Prostate hypercontractility has been proposed to contribute to BPH-related LUTS. The aim was to evaluate the effects of inhibiting stromal interaction molecule (STIM)/Orai calcium entry system on adrenergic and neurogenic contractions in prostate (HP) and bladder neck (HB) strips from BPH patients. Effects of STIM/Orai inhibition on adrenergic and neurogenic contractions of HP from organ donors (ODs) without BPH were also evaluated. HP and HB strips were obtained from 20 patients with BPH undergoing radical prostatectomy and from six OD at the time of organ collection for transplantation. Tissues were functionally evaluated for isometric tension recording. STIM-1, Orai1, and Orai3 protein expressions were determined in prostate tissues. STIM-1 was also localized by immunofluorescence in prostate sections. Norepinephrine-induced and neurogenic contractions were significantly reduced by STIM/Orai inhibition with YM-58483 (20 µM) in HP from BPH patients but not in tissues from ODs. STIM/Orai inhibition failed to significantly modify contraction of HB from BPH patients. Protein expression of STIM-1 was significantly elevated in HP from BPH patients. Functional contribution of STIM/Orai system to contractile tone is relevant in prostate when BPH is present, probably related to increased expression of STIM-1. Inhibition of STIM/Orai could have therapeutic implications for the management of BPH patients by alleviating prostatic hypercontraction. Full article

The nutritional and quality characteristics of improved vegetable soybean genotypes were evaluated and compared with those of a grain-type soybean at the R6 (green maturity) and R8 (physiological maturity) stages. Significant variation (p < 0.05) was observed among genotypes for all measured traits. The overall quality parameters increased from the R6 (green maturity) stage to the R8 (physiological maturity) stage. Among the R6-stage genotypes, AVSB2001 recorded the highest contents of protein (15.30 ± 0.57 g/100 g), ash (2.31 ± 0.06 g/100 g), fat (8.05 ± 0.17 g/100 g), and calcium (140.78 ± 0.97 mg/100 g). The genotype Karune exhibited significantly higher levels of total sugars, non-reducing sugars, iron, and magnesium than the other entries. At the R8 stage, Swarna Vasundhara showed the highest protein content (39.23%), while AGS 447 recorded the highest values for fat, total sugars, in vitro protein digestibility, iron, copper, magnesium, and manganese. Notably, in vitro protein digestibility was lower across all genotypes at the R8 stage compared to the R6 stage. These findings suggest that selected vegetable soybean genotypes possess substantial nutritional value and can contribute meaningfully to meeting the recommended dietary allowance (RDA) across different age and occupational groups, underscoring this research’s potential public health impact. Based on stage-specific quality profiles, R6-stage genotypes may be better suited for fresh vegetables, whereas R8-stage genotypes can be utilized similarly to grain-type soybean for processing into products such as dhal, oil, flour, and other value-added foods. Full article

Aminoglycoside antibiotics are critical in clinical use for treating severe infections, but they can occasionally cause irreversible sensorineural hearing loss. To establish a rational pathway for otoprotectant discovery, we provide an integrated, three-tier methodology—comprising cell-model selection, transcriptomic analysis, and a gentamicin–Texas Red (GTTR) uptake assay—to guide the development of otoprotective strategies. We first utilized two murine auditory cell lines—UB/OC-2 and HEI-OC1. We focused on TMC1 and OCT2 and further explored the underlying mechanisms of ototoxicity. UB/OC-2 exhibited a higher sensitivity to gentamicin, which correlated with elevated OCT2 expression confirmed via RT-PCR and Western blot. Transcriptomic analysis revealed upregulation of PI3K-Akt, calcium, and GPCR-related stress pathways in gentamicin-treated HEI-OC1 cells. Protein-level analysis further confirmed that gentamicin suppressed phosphorylated Akt while upregulating ER stress markers (GRP78, CHOP) and apoptotic proteins (cleaved caspase 3, PARP). Co-treatment with PI3K inhibitors (LY294002, wortmannin) further suppressed Akt phosphorylation, supporting the role of PI3K-Akt signaling in auditory cells. To visualize drug entry, we used GTTR to evaluate its applicability as a fluorescence-based uptake assay in these cell lines, which were previously employed mainly in cochlear explants. Sodium thiosulfate (STS) and N-acetylcysteine (NAC) significantly decreased GTTR uptake, suggesting a protective effect against gentamicin-induced hair cell damage. In conclusion, our findings showed a complex ototoxic cascade involving OCT2- and TMC1-mediated drug uptake, calcium imbalance, ER stress, and disruption of PI3K-Akt survival signaling. We believe that UB/OC-2 cells serve as a practical in vitro model for mechanistic investigations and screening of otoprotective compounds. Additionally, GTTR may be a simple, effective method for evaluating protective interventions in auditory cell lines. Overall, this study provides molecular-level insights into aminoglycoside-induced ototoxicity and introduces a platform for protective strategies. Full article