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BackgroundChronic sympathetic stimulation drives desensitization and downregulation of β1 adrenergic receptor (β1AR) in heart failure. We aim to explore the differential downregulation subcellular pools of β1AR signaling in the heart.Methods and resultsWe applied chronic infusion of isoproterenol to induced cardiomyopathy in male C57BL/6J mice. We applied confocal and proximity ligation assay to examine β1AR association with L-type calcium channel, ryanodine receptor 2, and SERCA2a ((Sarco)endoplasmic reticulum calcium ATPase 2a) and Förster resonance energy transfer-based biosensors to probe subcellular β1AR-PKA (protein kinase A) signaling in ventricular myocytes. Chronic infusion of isoproterenol led to reduced β1AR protein levels, receptor association with L-type calcium channel and ryanodine receptor 2 measured by proximity ligation (puncta/cell, 29.65 saline versus 14.17 isoproterenol, P

Mitochondrial Ca2+ overload can mediate mitochondria-dependent cell death, a major contributor to several human diseases. Indeed, Duchenne muscular dystrophy (MD) is driven by dysfunctional Ca2+ influx across the sarcolemma that causes mitochondrial Ca2+ overload, organelle rupture, and muscle necrosis. The mitochondrial Ca2+ uniporter (MCU) complex is the primary characterized mechanism for acute mitochondrial Ca2+ uptake. One strategy for preventing mitochondrial Ca2+ overload is deletion of the Mcu gene, the pore forming subunit of the MCU-complex. Conversely, enhanced MCU-complex Ca2+ uptake is achieved by deleting the inhibitory Mcub gene. Here we show that myofiber-specific Mcu deletion was not protective in a mouse model of Duchenne MD. Specifically, Mcu gene deletion did not reduce muscle histopathology, did not improve muscle function, and did not prevent mitochondrial Ca2+ overload. Moreover, myofiber specific Mcub gene deletion did not augment Duchenne MD muscle pathology. Interestingly, we observed MCU-independent Ca2+ uptake in dystrophic mitochondria that was sufficient to drive mitochondrial permeability transition pore (MPTP) activation and skeletal muscle necrosis, and this same type of activity was observed in heart, liver, and brain mitochondria. These results demonstrate that mitochondria possess an uncharacterized MCU-independent Ca2+ uptake mechanism that is sufficient to drive MPTP-dependent necrosis in MD in vivo.

Cardiac dysfunction is a hallmark of aging in humans and mice. Here we report that a two-week treatment to restore youthful Bridging Integrator 1 (BIN1) levels in the hearts of 24-month-old mice rejuvenates cardiac function and substantially reverses the aging phenotype. Our data indicate that age-associated overexpression of BIN1 occurs alongside dysregulated endosomal recycling and disrupted trafficking of cardiac CaV1.2 and type 2 ryanodine receptors. These deficiencies affect channel function at rest and their upregulation during acute stress. In vivo echocardiography reveals reduced systolic function in old mice. BIN1 knockdown using an adeno-associated virus serotype 9 packaged shRNA-mBIN1 restores the nanoscale distribution and clustering plasticity of ryanodine receptors and recovers Ca2+ transient amplitudes and cardiac systolic function toward youthful levels. Enhanced systolic function correlates with increased phosphorylation of the myofilament protein cardiac myosin binding protein-C. These results reveal BIN1 knockdown as a novel therapeutic strategy to rejuvenate the aging myocardium.

Voltage‐gated calcium channels (VGCC) are abundant in the central nervous system and serve a broad spectrum of functions, either directly in cellular excitability or indirectly to regulate Ca2+ homeostasis. Ca2+ ions act as one of the main connections in excitation–transcription coupling, muscle contraction and excitation–exocytosis coupling, including synaptic transmission. In recent years, many genes encoding VGCCs main α or additional auxiliary subunits have been associated with epilepsy. This review sums up the current state of knowledge on disease mechanisms and provides guidance on disease‐specific therapies where applicable. [ABSTRACT FROM AUTHOR]

Background and Purpose: The chemotherapy agent oxaliplatin can give rise to oxaliplatin‐induced peripheral neuropathy (OIPN). Here, we investigated whether T‐type calcium channels (Cav3) contribute to OIPN. Experimental Approach: We chronically treated mice with oxaliplatin and assessed pain responses and changes in expression of Cav3.2 calcium channels. We also tested the effects of T‐type channel blockers on cold sensitivity in wild‐type and Cav3.2 null mice. Key Results: Oxaliplatin treatment led to mechanical and cold hypersensitivity in male and female mice. Mechanical hypersensitivity persisted in Cav3.2 null mice of both sexes. Intraperitoneal or intrathecal delivery of pan T‐type channel inhibitors attenuated mechanical hypersensitivity in wild‐type but not Cav3.2 null mice. Remarkably cold hypersensitivity occurred in female but not male Cav3.2 null mice even without oxaliplatin treatment. Unexpectedly, intrathecal, intraplantar or intraperitoneal delivery of T‐type channel inhibitors Z944 or TTA‐P2 transiently induced cold hypersensitivity in both male and female wild‐type mice. Acute knockdown of specific Cav3 isoforms revealed that the depletion of Cav3.1 in males and depletion of either Cav3.1 or Cav3.2 in females triggered cold hypersensitivity. Finally, reducing Cav3.2 expression by disrupting the interactions between Cav3.2 and the deubiquitinase USP5 with the small organic molecule II‐2 reversed oxaliplatin‐induced mechanical and cold hypersensitivity and importantly did not trigger cold allodynia. Conclusion and Implications: Altogether, our data indicate that T‐type channels differentially contribute to the regulation of cold and mechanical hypersensitivity, and raise the possibility that T‐type channel blockers could promote cold allodynia. [ABSTRACT FROM AUTHOR]

Many patients with bipolar disorder (BD) do not respond to or have difficulties tolerating lithium and/or other mood stabilizing agents. There is a need for personalized treatments based on biomarkers in guiding treatment options. The calcium voltage-gated channel CACNA1C is a promising candidate for developing personalized treatments. CACNA1C is implicated in BD by genome-wide association studies and several lines of evidence suggest that targeting L-type calcium channels could be an effective treatment strategy. However, before such individualized treatments can be pursued, biomarkers predicting treatment response need to be developed. As a first step in testing the hypothesis that CACNA1C genotype is associated with serum levels of CACNA1C, we conducted ELISA measures on serum samples from 100 subjects with BD and 100 control subjects. We observed significantly higher CACNA1C (p < 0.01) protein levels in subjects with BD. The risk single nucleotide polymorpshism (SNP) (rs11062170) showed functional significance as subjects homozygous for the risk allele (CC) had significantly greater CACNA1C protein levels compared to subjects with one (p = 0.013) or no copies (p = 0.009). We observed higher somatostatin (SST) (p < 0.003) protein levels and lower levels of the clock protein aryl hydrocarbon receptor nuclear translocator-like (ARTNL) (p < 0.03) and stress signaling factor corticotrophin releasing hormone (CRH) (p < 0.001) in BD. SST and period 2 (PER2) protein levels were associated with both alcohol dependence and lithium response. Our findings represent the first evidence for increased serum levels of CACNA1C in BD. Along with altered levels of SST, ARNTL, and CRH our findings suggest CACNA1C is associated with circadian rhythm and stress response disturbances in BD. • CACNA1C serum levels are increased in bipolar disorder, associated with the rs11062170 risk allele. • Serum levels of stress signaling molecules and clock molecules are altered in the same patients • Serum levels of period 2 are associated with alcohol dependence along with a trend for both period 2 and somatostatin with lithium response in bipolar disorder [ABSTRACT FROM AUTHOR]

Although neurons release neurotransmitter before contact, the role for this release in synapse formation remains unclear. Cortical synapses do not require synaptic vesicle release for formation (Verhage et al., 2000; Sando et al., 2017; Sigler et al., 2017; Held et al., 2020), yet glutamate clearly regulates glutamate receptor trafficking (Roche et al., 2001; Nong et al., 2004) and induces spine formation (Engert and Bonhoeffer, 1999; Maletic-Savatic et al., 1999; Toni et al., 1999; Kwon and Sabatini, 2011; Oh et al., 2016). Using rat and murine culture systems to dissect molecular mechanisms, we found that glutamate rapidly decreases synapse density specifically in young cortical neurons in a local and calcium-dependent manner through decreasing N-methyl-D-aspartate receptor (NMDAR) transport and surface expression as well as cotransport with neuroligin (NL1). Adhesion between NL1 and neurexin 1 protects against this glutamate-induced synapse loss. Major histocompatibility I (MHCI) molecules are required for the effects of glutamate in causing synapse loss through negatively regulating NL1 levels in both sexes. Thus, like acetylcholine at the neuromuscular junction, glutamate acts as a dispersal signal for NMDARs and causes rapid synapse loss unless opposed by NL1-mediated trans-synaptic adhesion. Together, glutamate, MHCI, and NL1 mediate a novel form of homeostatic plasticity in young neurons that induces rapid changes in NMDARs to regulate when and where nascent glutamatergic synapses are formed. [ABSTRACT FROM AUTHOR]

Schizophrenia is a complex neurological disorder characterized by significant impairment in the perception of reality and changes in behavior. Genetic and environmental factors influence the development of schizophrenia. CACNA1C , which encodes a subunit of a voltage-dependent calcium channel, has been associated with various neurological disorders, including schizophrenia. Several studies have been performed in different populations to explore the association of common genetic variants in the CACNA1C gene with susceptibility to the development of schizophrenia, but results remain contradictory. To draw a definitive conclusion on the association between CACNA1C polymorphisms and schizophrenia, we conducted a meta-analysis focusing on three commonly studied polymorphisms: rs1006737, rs4765905, and rs2007044. For the meta-analysis, a comprehensive literature search was performed using PubMed, Scopus, Science Direct and Google Scholar databases. Data was retrieved, and the meta-analysis was performed using CMA v4 software. The meta-analysis revealed a significant association between rs1006737 and rs2007044 and schizophrenia in the overall population, while no such association was found for rs4765905. Population-wise analysis suggested that all three polymorphisms were significantly associated with schizophrenia in the Asian population and that rs1006737 was significantly associated with schizophrenia in Europeans. We also performed a Trial Sequential Analysis (TSA), which supported our findings. Some report-based assay studies have suggested a role for these polymorphisms in schizophrenia, but further case-control studies are needed to confirm the association of rs4765905 and rs2007044 with the disorder. [ABSTRACT FROM AUTHOR]

Spinocerebellar ataxias (SCAs) are characterized by substantial phenotypic variability. Among them, SCA42 is a rare non-expansion entity presenting with slowly progressive cerebellar syndrome but whose clinical spectrum may be also wider. A 53-year-old male presented with progressive myoclonus-ataxia and intellectual disability. Genetic screening revealed a novel c.3835G > A (p. Asp1279Asn) variant in the CACNA1G gene. SCA42 is a rare non-expansion SCA caused by mutations in CACNA1G on chromosome 17q21, encoding the Ca(V)3.1, a low-threshold voltage-gated T-type calcium channel. The novel variant we identified is potentially involved in channel activity. This case expands the knowledge regarding CACNA1G-associated phenotype and highlights the importance of genetic screening in myoclonus-ataxia disorders. [ABSTRACT FROM AUTHOR]

Background: Schisandra chinensis is widely applied in the prevention and treatment of asthma in China, but the material basis for the anti-asthmatic effect of S. chinensis is unclear. Our previous studies found that the lignans from S. chinensis can relax tracheal smooth muscle in rats. Schisandrol A (SCA) is a representative monomer of S. chinensis lignans with high content and activity. Purpose: This study was aimed at further exploring the relaxation effect of SCA and its mechanism on the isolated tracheal smooth muscle of rats through tracheal perfusion experiments. Materials and Methods: The isolated rat tracheal ring was precontracted with acetylcholine (ACh). Then, the impact of SCA on the tension of precontracted tracheal ring was studied. Verapamil (L-type calcium channel blocker) and four potassium channel blockers, including glibenclamide, tetraethylamine, 4-aminopyridine (4-AP), and barium chloride (BaCl2), as well as propranolol (β-adrenergic receptor antagonist), were respectively used to precontract the tracheal ring for investigation. Results: SCA could dose-dependently reduce the ACh-induced contraction of the tracheal ring, and the verapamil and 4-AP could weaken this effect, while BaCl2, glibenclamide, tetraethylamine, and propranolol did not show this effect. Conclusion: SCA can significantly relax the effect of tracheal smooth muscle of rats, and the underlying mechanism might be involved in the blocking of L-type Ca2+ channels and activating the voltage-dependent potassium channels (KV). [ABSTRACT FROM AUTHOR]

Oocytes and early embryos are exposed to many uncontrollable factors that trigger endoplasmic reticulum (ER) stress during in vitro culture. Prevention of ER stress is an effective way to improve the oocyte maturation rate and oocyte quality. Increasing evidence suggests that dietary intake of sufficient n-3 polyunsaturated fatty acids (PUFAs) is associated with health benefits, particularly in the domain of female reproductive health. We found that supplementation of eicosatrienoic acid (ETA) during in vitro maturation (IVM) of oocyte significantly downregulated ER stress-related genes. Mitochondria-associated membranes (MAMs) are communications areas between the ER and mitochondria. Inositol 1,4,5-trisphosphate receptor (IP3R) is a key calcium channels in MAMs and, participates in the regulation of many cellular functions. Notably, the MAM area was significantly decreased in ETA-treated oocytes. CDGSH iron sulfur domain 2 (CISD2) is presents in MAMs, but its role in oocytes is unknown. ETA treatment significantly increased CISD2 expression, and siRNA-mediated knockdown of CISD2 blocked the inhibitory effect of ETA on IP3R. Transcriptomic sequencing and immunoprecipitation experiments showed that ETA treatment significantly decreased expression of the E3 ubiquitin ligase PRKN. PRKN induced ubiquitination and degradation of CISD2, indicating that the PRKN-mediated ubiquitin-proteasome system regulates CISD2. In conclusion, our study reveals the mechanism by which ETA supplementation during IVM alleviates mitochondrial calcium overload under ER stress conditions by decreasing PRKN-mediated ubiquitination of CISD2 and facilitating inhibition of IP3R by CISD2/BCL-2. This improves oocyte quality and subsequent embryo developmental competence prior to implantation. [Display omitted] • Supplementation with ETA improves the quality of oocytes in vitro culture. • ETA regulates calcium homeostasis through PRKN-mediated ubiquitination of CISD2. • CISD2 agonists enhance oocyte and subsequent embryo developmental competence. [ABSTRACT FROM AUTHOR]

BACKGROUND: RNA interference (RNAi) is an endogenous eukaryote viral defence mechanism representing a unique form of post‐transcriptional gene silencing. Owing to its high specificity, this technology is being developed for use in dsRNA‐based biopesticides for control of pest insects. Whilst many lepidopteran species are recalcitrant to RNAi, Tuta absoluta, a polyphagous insect responsible for extensive crop damage, is sensitive. Ryanodine receptors (RyRs) are intracellular calcium channels regulating calcium ion (Ca2+) release. The chemical pesticide class of diamides functions agonistically against lepidopteran RyR, resulting in uncontrolled Ca2+ release, feeding cessation and death. Resistance to diamides has emerged in T. absoluta, derived from RyR point mutations. RESULTS: RNAi was used to target RyR transcripts of T. absoluta. Data presented here demonstrate the systemic use of exogenous T. absoluta RyR‐specific (TaRy) dsRNA in tomato plants (Solanum lycopersicum) to significantly downregulate expression of the target gene, resulting in significant insect mortality and reduced leaf damage. Using a leaflet delivery system, daily dosing of 3 μg TaRy dsRNA for 72 h resulted in 50% downregulation of the target gene and 50% reduction in tomato leaf damage. Corrected larval mortality and adult emergence were reduced by 38% and 33%, respectively. TaRy dsRNA demonstrated stability in tomato leaves ≤72 h after dosing. CONCLUSIONS: This work identifies TaRy as a promising target for RNAi control of this widespread crop pest. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: The β-adrenergic augmentation of cardiac contraction, by increasing the conductivity of L-type voltage-gated CaV1.2 channels, is of great physiological and pathophysiological importance. Stimulation of β-adrenergic receptors (βAR) activates protein kinase A (PKA) through separation of regulatory (PKAR) from catalytic (PKAC) subunits. Free PKAC phosphorylates the inhibitory protein Rad, leading to increased Ca2+ influx. In cardiomyocytes, the core subunit of CaV1.2, CaV1.2α1, exists in two forms: full-length or truncated (lacking the distal C-terminus (dCT)). Signaling efficiency is believed to emanate from protein interactions within multimolecular complexes, such as anchoring PKA (via PKAR) to CaV1.2α1 by A-kinase anchoring proteins (AKAPs). However, AKAPs are inessential for βAR regulation of CaV1.2 in heterologous models, and their role in cardiomyocytes also remains unclear. Results: We show that PKAC interacts with CaV1.2α1 in heart and a heterologous model, independently of Rad, PKAR, or AKAPs. Studies with peptide array assays and purified recombinant proteins demonstrate direct binding of PKAC to two domains in CaV1.2α1-CT: the proximal and distal C-terminal regulatory domains (PCRD and DCRD), which also interact with each other. Data indicate both partial competition and possible simultaneous interaction of PCRD and DCRD with PKAC. The βAR regulation of CaV1.2α1 lacking dCT (which harbors DCRD) was preserved, but subtly altered, in a heterologous model, the Xenopus oocyte. Conclusions: We discover direct interactions between PKAC and two domains in CaV1.2α1. We propose that these tripartite interactions, if present in vivo, may participate in organizing the multimolecular signaling complex and fine-tuning the βAR effect in cardiomyocytes. [ABSTRACT FROM AUTHOR]

Cannabidiol (CBD), a non-psychoactive compound derived from the cannabis plant, has been extensively studied for its potential therapeutic effects on various central nervous system (CNS) disorders, including epilepsy, chronic pain, Parkinson's disease, and stress-related neuropsychiatric disorders. However, the pharmacological mechanisms of CBD have not been fully elucidated due to the complexity of their targets. In this study, we reported that the transient receptor potential canonical 4 (TRPC4) channel, a calcium-permeable, non-selective cation channel, could be inhibited by CBD. TRPC4 is highly abundant in the central nervous system and plays a critical role in regulating axonal regeneration, neurotransmitter release, and neuronal network activity. Here, we used whole-cell electrophysiology and intracellular calcium measurements to identify the inhibitory effects of CBD on TRPC4, in which CBD was found to inhibit TRPC4 channel with an IC50 value of 1.52 μM TRPC4 channels function as receptor-operated channels (ROC) and could be activated by epinephrine (EP) via G proteins. We show that CBD can inhibit EP-evoked TRPC4 current in vitro and EP-evoked neuronal excitability in the medial prefrontal cortex (mPFC). These results are consistent with the action of TRPC4-specific inhibitor Pico145, suggesting that TRPC4 works as a functional ionotropic receptor of CBD. This study identified TRPC4 as a novel target for CBD in the CNS and suggested that CBD could reduce the pyramidal neuron excitability by inhibiting TRPC4-containing channels in the mPFC. [ABSTRACT FROM AUTHOR]

Key points As a member of the transient receptor potential (TRP) superfamily of ion channels, TRPV5 is a unique Ca2+‐selective channel important for active reabsorption of Ca2+ in the kidney. TRPV5‐mediated Ca2+ entry into the cell is controlled by a negative feedback mechanism, in which calmodulin (CaM) blocks the TRPV5 pore upon Ca2+ binding. Combining microscopy techniques and biochemical assays, the present study uncovered an auxiliary role for CaM in the regulation of human (h)TRPV5 intracellular trafficking. Overexpressed hTRPV5 was mainly localised to the endoplasmic reticulum (ER) and associated with peripheral ER tubules. Limiting expression using the HEK293 TET‐off system revealed that hTRPV5 trafficked through the endocytic recycling pathway. CaM co‐localised with hTRPV5 at intracellular sites and overexpression of CaM slowed hTRPV5 exit from the ER. In accordance, CaM binding‐disrupting truncations of the TRPV5 C‐terminus (698X) or knockdown of endogenous CaM by small interfering RNA resulted in an increased fraction of TRPV5 that localised to the plasma membrane. hTRPV5 expressing cells had an increased intracellular Ca2+ concentration upon knockdown of CaM. The protein abundance of the Ca2+ impermeable hTRPV5‐D542 mutant is also regulated by CaM, which suggests that the mode of action is independent of disrupted intracellular calcium concentrations. In conclusion, our study reveals a novel role for CaM in Ca2+‐dependent TRPV5 regulation, modulating TRPV5 intracellular trafficking. The renal Ca2+ channel TRPV5 is a crucial player in maintenance of the body's Ca2+ homeostasis. Ca2+ transport through TRPV5 is controlled by single channel activity, as well as TRPV5 plasma membrane abundance. Calmodulin (CaM) co‐localised with TRPV5 at intracellular sites and retained TRPV5 in the endoplasmic reticulum. Disrupted CaM–TRPV5 binding or knockdown of endogenous CaM by small interfering RNA (siRNA) resulted in an increased TRPV5 plasma membrane abundance. Knockdown of endogenous CaM by siRNA resulted in increased intracellular Ca2+ concentrations. The regulation of TRPV5 trafficking by CaM is independent of the effect of CaM on intracellular Ca2+ concentrations. This study reveals a novel role for CaM in Ca2+‐dependent TRPV5 regulation, next to its ability to directly block the TRPV5 channel pore, by modulating TRPV5 trafficking in the secretory pathway. [ABSTRACT FROM AUTHOR]

P/Q-type (Cav2.1) calcium channels mediate Ca2+ influx essential for neuronal excitability and synaptic transmission. The CACNA1A gene, encoding the Cav2.1 pore forming subunit, is highly expressed throughout the mammalian central nervous system. Alternative splicing of Cav2.1 pre-mRNA generates diverse channel isoforms with distinct biophysical properties and drug affinities, which are differentially expressed in nerve tissues. Splicing variants can also affect channel function under pathological conditions although their phenotypic implication concerning inherited neurological disorders linked to CACNA1A mutations remains unknown. Here, we quantified the expression of Cav2.1 exon 24 (e24) spliced transcripts in human nervous system samples, finding different levels of expression within discrete regions. The corresponding Cav2.1 variants, differing by the presence (+) or absence (Δ) of Ser-Ser-Thr-Arg residues (SSTR) in the domain III S3-S4 linker, were functionally characterized using patch clamp recordings. Further, the + /ΔSSTR isoforms were used to demonstrate the differential impact of the Familial Hemiplegic Migraine Type 1 (FHM-1) S218L mutation, located in the domain I S4-S5 linker, on the molecular structure and electrophysiological properties of Cav2.1 isoforms. S218L has a prominent effect on the voltage-dependence of activation of +SSTR channels when compared to ΔSSTR, indicating a differential effect of the mutation depending on splice-variant context. Structural modeling based upon Cav2.1 cryo-EM data provided further insight reflecting independent contributions of amino acids in distant regions of the channel on gating properties. Our modelling indicates that by increasing hydrophobicity the Leu218 mutation contributes to stabilizing a structural conformation in which the domain I S4-S5 linker is oriented alongside the inner plasma membrane, similar to that occurring when S4 is translocated upon activation.The SSTR insertion appears to exert an influence in the local electric field of domain III due to an change in the distribution of positively charged regions surrounding the voltage sensing domain, which we hypothesize impacts its movement during the transition to the open state. In summary, we reveal molecular changes correlated with distinct functional effects provoked by S218L FHM-1 mutation in hCav2.1 splice isoforms whose differential expression could impact the manifestation of the neurological disorder. [ABSTRACT FROM AUTHOR]

The risk of many human diseases including cardiovascular diseases, cancer, neurodegenerative diseases, and musculoskeletal disorders rises significantly in the elderly. With the increase in the aging population, it is becoming increasingly important to understand the biology of healthy aging and develop interventions that slow down the aging process or prevent age‐related diseases. In this study, by a high‐throughput screen in Caenorhabditis elegans (C. elegans), we identified 11 small molecules that promote healthy aging. Among them, Carbamazepine (a voltage‐gated channels inhibitor) and Calmagite (a calcium and magnesium indicator) enhanced serotonin (5‐HT) and dopamine (DA) levels, extended lifespan, and preserved several important behaviors in aging C. elegans. These behaviors include slowing responses to food, pharyngeal pumping, locomotion, and male mating. Interestingly, we further found that administration of Carbamazepine or Calmagite alleviated hyperexcitability of aging male diagonal muscles and improved behavioral performance by ameliorating Ca2+ homeostasis. Mechanistically, administration of Carbamazepine or Calmagite induced nuclear translocation of the transcription factor DAF‐16 and thus up‐regulated its downstream genes numr‐1/−2, which are known to promote resistance to metal‐induced stresses and longevity. Taken together, our study offers a way for the discovery of drugs that promote healthy aging, and provides potential interventions for preventing behavioral deterioration in the elderly. [ABSTRACT FROM AUTHOR]

Emerging evidence has indicated a possible link between attenuation of contractility in aortic smooth muscle cells and pathogenesis of aortic dissection, as revealed through comprehensive, multi-omic analyses of familial thoracic aortic aneurysm and dissection models. While L-type voltage-gated calcium channels have been extensively investigated for their roles in smooth muscle contraction, more recent investigations have suggested that downregulation of T-type voltage-gated calcium channels, rather than their L-type counterparts, may be more closely associated with impaired contractility observed in vascular smooth muscle cells. This review provides a detailed examination of T-type voltage-gated calcium channels, highlighting their structure, electrophysiology, biophysics, expression patterns, functional roles, and potential mechanisms through which their downregulation may contribute to reduced contractile function. Furthermore, the application of multi-omic approaches in investigating calcium channels is discussed. [ABSTRACT FROM AUTHOR]

Neurodevelopmental disorders (NDDs) are a group of conditions affecting brain development, with variable degrees of severity and heterogeneous clinical features. They include intellectual disability (ID), autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), often coexisting with epilepsy, extra-neurological comorbidities, and multisystemic involvement. In recent years, next-generation sequencing (NGS) technologies allowed the identification of several gene pathogenic variants etiologically related to these disorders in a large cohort of affected children. These genes encode proteins involved in synaptic homeostasis, such as SNARE proteins, implicated in calcium-triggered pre-synaptic release of neurotransmitters, or channel subunit proteins, such as post-synaptic ionotropic glutamate receptors involved in the brain's fast excitatory neurotransmission. In this narrative review, we dissected emerged molecular mechanisms related to NDDs and epilepsy due to defects in pre- and post-synaptic transmission. We focused on the most recently discovered SNAREopathies and AMPA-related synaptopathies. [ABSTRACT FROM AUTHOR]

Abnormalities of tracheal smooth muscle (SM) formation are associated with several clinical disorders including tracheal stenosis and tracheomalacia. However, the cellular and molecular mechanisms underlying tracheal SM formation remain poorly understood. Here, it is shown that the T‐type calcium channel CACNA1H is a novel regulator of tracheal SM formation and contraction. Cacna1h in an ethylnitrosourea forward genetic screen for regulators of respiratory disease using the mouse as a model is identified. Cacna1h mutants exhibit tracheal stenosis, disorganized SM and compromised tracheal contraction. CACNA1H is essential to maintain actin polymerization, which is required for tracheal SM organization and tube formation. This process appears to be partially mediated through activation of the actin regulator RhoA, as pharmacological increase of RhoA activity ameliorates the Cacna1h‐mutant trachea phenotypes. Analysis of human tracheal tissues indicates that a decrease in CACNA1H protein levels is associated with congenital tracheostenosis. These results provide insight into the role for the T‐type calcium channel in cytoskeletal organization and SM formation during tracheal tube formation and suggest novel targets for congenital tracheostenosis intervention. [ABSTRACT FROM AUTHOR]

Morphogen gradients instruct cells to pattern tissues. Although the mechanisms by which morphogens transduce chemical signals have been extensively studied, the roles and regulation of the physical communication between morphogen-receiver cells remain unclear. Here, we show that the Wnt/ß-catenin-morphogen gradient, which patterns the embryonic anterior-posterior (AP) axis, generates intercellular tension gradients along the AP axis by controlling membrane cadherin levels in zebrafish embryos. This "mechano-gradient" is used for the cell competition-driven correction of noisy morphogen gradients. Naturally and artificially generated unfit cells, producing noisy Wnt/ß-catenin gradients, induce local deformation of the mechano-gradients that activate mechanosensitive calcium channels in the neighboring fit cells, which then secrete annexin A1a to kill unfit cells. Thus, chemo-mechanical interconversion-mediated competitive communication between the morphogen-receiver cells ensures precise tissue patterning. [ABSTRACT FROM AUTHOR]

Alarmins are classified by their release from damaged or ruptured cells. Many alarmins have been found to increase vascular tone and oppose endothelium‐dependent dilatation (EDD). Interleukin (IL)‐33 plays a prominent role in lung injury and can be released during vascular injury and in chronic studies found to be cardioprotective. Our recent work has implicated IL‐33 in acute vascular dysfunction following inhalation of engineered nanomaterials (ENM). However, the mechanisms linking IL‐33 to vascular tone have not been interrogated. We therefore aimed to determine whether IL‐33 directly influenced microvascular tone and endothelial function. Isolated feed arteries and in vivo arterioles from male and female Sprague–Dawley rats were used to determine direct vascular actions of IL‐33. Mesenteric feed arteries and arterioles demonstrated reduced intraluminal diameters when treated with increasing concentrations of recombinant IL‐33. IL‐33 activated extracellular signal regulated kinase (ERK)1/2 of rat aortic smooth muscle cells but not phosphorylation of myosin light chain kinase. This suggested IL‐33 may sensitize arterioles to Ca2+‐mediated responses. Indeed, IL‐33 augmented the myogenic‐ and phenylephrine‐induced vasoconstriction. Additionally, incubation of arterioles with 1 ng IL‐33 attenuated ACh‐mediated EDD. Mechanistically, in human aortic endothelial cells, we demonstrate that IL‐33‐mediated ERK1/2 activation leads to inhibitory phosphorylation of serine 602 on endothelial nitric oxide synthase. Finally, we demonstrate that IL‐33‐ERK1/2 contributes to vascular tone following two known inducers of IL‐33; ENM inhalation and the rupture endothelial cells. The present study provides novel evidence that IL‐33 increases vascular tone via canonical ERK1/2 activation in microvascular smooth muscle and endothelium. Altogether, it is suggested IL‐33 plays a critical role in microvascular homeostasis following barrier cell injury. Key points: Interleukin (IL)‐33 causes a concentration‐dependent reduction in feed artery diameter.IL‐33 acts on vascular smooth muscle cells to augment Ca2+‐mediated processes.IL‐33 causes inhibitory phosphorylation of endothelial nitric oxide synthase and opposes endothelium‐dependent dilatation.Engineered nanomaterial‐induced lung injury and endothelial cell rupture in part act through IL‐33 to mediate increased vascular tone. [ABSTRACT FROM AUTHOR]

The house dust mite is the principal source of aero‐allergen worldwide. Exposure to mite‐derived allergens is associated with the development of asthma in susceptible individuals, and the majority of asthmatics are allergic to the mite. Mite‐derived allergens are functionally diverse and activate multiple cell types within the lung that result in chronic inflammation. Allergens activate store‐operated Ca2+ release‐activated Ca2+ (CRAC) channels, which are widely expressed in multiple cell types within the lung that are associated with the pathogenesis of asthma. Opening of CRAC channels stimulates Ca2+‐dependent transcription factors, including nuclear factor of activated T cells and nuclear factor‐κB, which drive expression of a plethora of pro‐inflammatory cytokines and chemokines that help to sustain chronic inflammation. Here, I describe drivers of asthma, properties of mite‐derived allergens, how the allergens are recognized by cells, the signalling pathways used by the receptors and how these are transduced into functional effects, with a focus on CRAC channels. In vivo experiments that demonstrate the effectiveness of targeting CRAC channels as a potential new therapy for treating mite‐induced asthma are also discussed, in tandem with other possible approaches. [ABSTRACT FROM AUTHOR]

Tetrandrine (Tet), a well-known drug of calcium channel blocker, has been broadly applied for anti-inflammatory and anti-fibrogenetic therapy. However, due to the functional diversity of ubiquitous calcium channels, potential side-effects may be expected. Our previous report revealed an inhibitory effect of Tet on myogenesis of skeletal muscle. Here, we found that Tet induced protein degradation resulting in the myofibril atrophy. Upon administration with a relative high dose (40 mg/kg) of Tet for 28 days, the mice displayed significantly reduced muscle mass, strength force, and myosin heavy chain (MyHC) protein levels. The MyHC reduction was further detected in C2C12 myotubes after treating with Tet. Interestingly, the expression of Atrogin-1 and Murf-1, the skeletal muscle specific E3 ligases of protein ubiquitin–proteasome system (UPS), was accordingly up-regulated, and the reduced MyHC was significantly mitigated by MG132, a 26S proteasome inhibitor, indicating a key role of UPS in the protein degradation of muscle cells. Further study showed that Tet induced autophagy also participated in the protein degradation. Mechanistically, Tet treatment caused ROS production in myotubes that in turn targeted on FoxO3/AKT signaling, resulting in the activation of UPS and autophagy processes that were involved in the protein degradation. Our study reveals a potential side-effect of Tet on skeletal muscle atrophy, particularly when the drug dose is relatively high. [ABSTRACT FROM AUTHOR]

Background and Purpose: Gastrointestinal tumours overexpress voltage‐gated calcium (CaV3) channels (CaV3.1, 3.2 and 3.3). CaV3 channels regulate cell growth and apoptosis colorectal cancer. Gossypol, a polyphenolic aldehyde found in the cotton plant, has anti‐tumour properties and inhibits CaV3 currents. A systematic study was performed on gossypol blocking mechanism on CaV3 channels and its potential anticancer effects in colon cancer cells, which express CaV3 isoforms. Experimental Approach: Transcripts for CaV3 proteins were analysed in gastrointestinal cancers using public repositories and in human colorectal cancer cell lines HCT116, SW480 and SW620. The gossypol blocking mechanism on CaV3 channels was investigated by combining heterologous expression systems and patch‐clamp experiments. The anti‐tumoural properties of gossypol were estimated by cell proliferation, viability and cell cycle assays. Ca2+ dynamics were evaluated with cytosolic and endoplasmic reticulum (ER) Ca2+ indicators. Key Results: High levels of CaV3 transcripts correlate with poor prognosis in gastrointestinal cancers. Gossypol blockade of CaV3 isoforms is concentration‐ and use‐dependent interacting with the closed, activated and inactivated conformations of CaV3 channels. Gossypol and CaV3 channels down‐regulation inhibit colorectal cancer cell proliferation by arresting cell cycles at the G0/G1 and G2/M phases, respectively. CaV3 channels underlie the vectorial Ca2+ uptake by endoplasmic reticulum in colorectal cancer cells. Conclusion and Implications: Gossypol differentially blocked CaV3 channel and its anticancer activity was correlated with high levels of CaV3.1 and CaV3.2 in colorectal cancer cells. The CaV3 regulates cell proliferation and Ca2+ dynamics in colorectal cancer cells. Understanding this blocking mechanism maybe improve cancer therapies. [ABSTRACT FROM AUTHOR]

Early osteoimmune microenvironment disorder at the interface between bone and implant can lead to implant loosening, which prolongs patient convalescence, exacerbates postoperative complications, and potentially results in implant failure. The timely regulation of macrophages primarily orchestrates the entire long‐term regeneration process. Here, it is proposed to precisely direct macrophage polarization using localized photoelectrical signals generated by an excitable surface in response to remote stimulation via near‐infrared light (NIR). The photocurrent generated from the n–n heterojunction between calcium titanate (CaTiO3) and defective titanium dioxide (TiO2‐Vo) on the excitable surface can accurately direct macrophage polarization, suppressing acute inflammation at the early stage of post‐implantation and establishing a favorable osteoimmune microenvironment that promotes bone‐to‐implant integration. Mechanistic study reveals that photoelectric signals initiate increased calcium influx via voltage‐gated calcium ion channels, subsequently modulating calcium/calmodulin‐dependent protein kinase kinase 2 (Camkk2) and calcium/calmodulin‐dependent protein kinase I (Camk1) expression to regulate macrophage polarization. This optimization of the osteoimmune microenvironment results in enhanced mesenchymal stem cells (MSCs) recruitment and osteogenesis, ultimately accelerating bone‐to‐implant integration within 14 days post‐implantation. This research presents a novel method for adjusting in vivo spatiotemporal immune responses through the use of noninvasive and externally‐controlled targeted stimulations. [ABSTRACT FROM AUTHOR]

Objective Methods Results Significance The cannabinoid cannabidiol has established antiseizure effects in drug‐resistant epilepsies such as Dravet syndrome and Lennox–Gastaut syndrome. Amorfrutin 2, honokiol, and magnolol are structurally similar to cannabinoids (cannabis‐like drugs) but derive from non‐cannabis plants. We aimed to study the antiseizure potential of these compounds in various mouse seizure models. In addition, we aimed to characterize their molecular pharmacology at cannabinoid CB1 and CB2 receptors and at T‐type calcium channels, which are known targets of the cannabinoids.Brain and plasma pharmacokinetic profiles were determined. Antiseizure activity was assessed against hyperthermia‐induced seizures in a Scn1a+/− mouse model of Dravet syndrome. We then elaborated on the most promising compounds in the maximal electroshock (MES) test in mice and the Gabrb3+/D120N mouse model of Lennox–Gastaut syndrome. Fluorescence‐based assays were used to examine modulatory activity at cannabinoid CB1 and CB2 receptors and T‐type calcium channel subtypes CaV3.1, CaV3.2, and CaV3.3 overexpressed in mammalian cells. Automated patch‐clamp electrophysiology was then used to confirm inhibitory activity on CaV3.1, CaV3.2, and CaV3.3 channels.Magnolol and honokiol had high brain‐to‐plasma ratios (3.55 and 7.56, respectively), unlike amorfrutin 2 (0.06). Amorfrutin 2 and magnolol but not honokiol significantly increased the body temperature threshold at which Scn1a+/− mice had a generalized tonic–clonic seizure. Both amorfrutin 2 and magnolol significantly decreased the proportion of mice exhibiting hindlimb extension in the MES test. Furthermore, magnolol reduced the number and duration of atypical absence seizures in Gabrb3+/D120N mice. The three compounds inhibited all T‐type calcium channel subtypes but were without specific activity at cannabinoid receptors.We show for the first time that amorfrutin 2 and magnolol display novel antiseizure activity in mouse drug‐resistant epilepsy models. Our results justify future drug discovery campaigns around these structural scaffolds that aim to develop novel antiseizure drugs for intractable epilepsies. [ABSTRACT FROM AUTHOR]

Myofascial orofacial pain, traditionally viewed as a nociceptive pain condition, also exhibits characteristics consistent with nociplastic pain—pain arising from altered nociception without clear evidence of tissue damage. Evidence supporting myofascial orofacial pain as nociplastic pain includes clinical observations of central sensitisation in patients, even in the absence of visible inflammation. Sensitisation is characterised by heightened responsiveness of nociceptive neurons to normal stimuli or activation by normally subthreshold stimuli, either in the peripheral or central nervous system. It is linked to maladaptive neuroplastic changes, including increased functional potentiation and altered expression of neuronal ion channels, receptors and neurotransmitters. This mini-review presents insights from existing evidence regarding altered nociception and its relation to changes in the expression of neuronal ion channels in myofascial orofacial pain. Increased expression of transient receptor potential (TRP) vanilloid 1 channels (TRPV1), TRPV4, TRP ankyrin 1 channels (TRPA1), Piezo2 channels, P2X3 purinergic receptors, N-Methyl-D-Aspartate (NMDA) receptors and voltage-gated calcium channels in the trigeminal ganglion of rodents has been observed in association with myofascial orofacial pain. This evidence highlights the role of neuronal ion channels in the pathophysiology of myofascial orofacial pain and supports the involvement of nociplastic mechanisms. [ABSTRACT FROM AUTHOR]

The precise regulation of Ca2+ signals plays a crucial role in the physiological functions of neurons. Here, we investigated the rapid effect of glucocorticoids on Ca2+ signals in cultured hippocampal neurons from both female and male rats. In cultured hippocampal neurons, glucocorticoids inhibited the spontaneous somatic Ca2+ spikes generated by Kv2.1-organized Ca2+ microdomains. Furthermore, glucocorticoids rapidly reduced the cell surface expressions of Kv2.1 and CaV1.2 channels in hippocampal neurons. In HEK293 cells transfected with Kv2.1 alone, glucocorticoids significantly reduced the surface expression of Kv2.1 with little effect on K+ currents. In HEK293 cells transfected with CaV1.2 alone, glucocorticoids inhibited CaV1.2 currents but had no effect on the cell surface expression of CaV1.2. Notably, in the presence of wild-type Kv2.1, glucocorticoids caused a decrease in the surface expression of CaV1.2 channels in HEK293 cells. However, this effect was not observed in the presence of nonclustering Kv2.1S586A mutant channels. Live-cell imaging showed that glucocorticoids rapidly decreased Kv2.1 clusters on the plasma membrane. Correspondingly, Western blot results indicated a significant increase in the cytoplasmic level of Kv2.1, suggesting the endocytosis of Kv2.1 clusters. Glucocorticoids rapidly decreased the intracellular cAMP concentration and the phosphorylation level of PKA in hippocampal neurons. The PKA inhibitor H89 mimicked the effect of glucocorticoids on Kv2.1, while the PKA agonist forskolin abrogated the effect. In conclusion, glucocorticoids rapidly suppress CaV1.2-mediated Ca2+ signals in hippocampal neurons by promoting the endocytosis of Kv2.1 channel clusters through reducing PKA activity. [ABSTRACT FROM AUTHOR]

Background and Aims Intravenous iron therapies contain iron–carbohydrate complexes, designed to ensure iron becomes bioavailable via the intermediary of spleen and liver reticuloendothelial macrophages. How other tissues obtain and handle this iron remains unknown. This study addresses this question in the context of the heart. Methods A prospective observational study was conducted in 12 patients receiving ferric carboxymaltose (FCM) for iron deficiency. Myocardial, spleen, and liver magnetic resonance relaxation times and plasma iron markers were collected longitudinally. To examine the handling of iron taken up by the myocardium, intracellular labile iron pool (LIP) was imaged in FCM-treated mice and cells. Results In patients, myocardial relaxation time T1 dropped maximally 3 h post-FCM, remaining low 42 days later, while splenic T1 dropped maximally at 14 days, recovering by 42 days. In plasma, non-transferrin-bound iron (NTBI) peaked at 3 h, while ferritin peaked at 14 days. Changes in liver T1 diverged among patients. In mice, myocardial LIP rose 1 h and remained elevated 42 days after FCM. In cardiomyocytes, FCM exposure raised LIP rapidly. This was prevented by inhibitors of NTBI transporters T-type and L-type calcium channels and divalent metal transporter 1. Conclusions Intravenous iron therapy with FCM delivers iron to the myocardium rapidly through NTBI transporters, independently of reticuloendothelial macrophages. This iron remains labile for weeks, reflecting the myocardium's limited iron storage capacity. These findings challenge current notions of how the heart obtains iron from these therapies and highlight the potential for long-term dosing to cause cumulative iron build-up in the heart. [ABSTRACT FROM AUTHOR]

Junctions between the ER and plasma membrane (PM) are implicated in calcium homeostasis, non-vesicular lipid transfer, and other cellular functions. Two ER proteins that function both as tethers to the PM via a polybasic C-terminus motif and as phospholipid transporters are brain-enriched TMEM24 (C2CD2L) and its paralog C2CD2. We report that both proteins also form a complex with band 4.1 family members, which in turn bind PM proteins including cell adhesion molecules such as SynCAM 1. This complex enriches TMEM24 and C2CD2 containing ER/PM junctions at sites of cell contacts. Dynamic properties of TMEM24-dependent ER/PM junctions are impacted when band 4.1 is part of the junction, as TMEM24 at cell-adjacent ER/PM junctions is not shed from the PM by calcium rise, unlike TMEM24 at non-cell adjacent junctions. Lipid transport between the ER and the PM by TMEM24 and C2CD2 at sites where cells, including neurons, contact other cells may participate in adaptive responses to cell contact-dependent signaling. [ABSTRACT FROM AUTHOR]

The mitochondrial calcium uniporter channel (MCUC) mediates mitochondrial calcium entry, regulating energy metabolism and cell death. Although several MCUC components have been identified, the molecular basis of mitochondrial calcium signaling networks and their remodeling upon changes in uniporter activity have not been assessed. Here, we map the MCUC interactome under resting conditions and upon chronic loss or gain of mitochondrial calcium uptake. We identify 89 high-confidence interactors that link MCUC to several mitochondrial complexes and pathways, half of which are associated with human disease. As a proof-of-concept, we validate the mitochondrial intermembrane space protein EFHD1 as a binding partner of the MCUC subunits MCU, EMRE, and MCUB. We further show a MICU1-dependent inhibitory effect of EFHD1 on calcium uptake. Next, we systematically survey compensatory mechanisms and functional consequences of mitochondrial calcium dyshomeostasis by analyzing the MCU interactome upon EMRE, MCUB, MICU1, or MICU2 knockdown. While silencing EMRE reduces MCU interconnectivity, MCUB loss-of-function leads to a wider interaction network. Our study provides a comprehensive and high-confidence resource to gain insights into players and mechanisms regulating mitochondrial calcium signaling and their relevance in human diseases. Synopsis: Mitochondrial calcium uptake through the uniporter channel MCUC is critical to cell signaling, metabolism, physiology, and disease. This study provides an unbiased and quantitative map of the MCUC interactome and its remodelling, both under resting conditions and after genetic perturbations. Tandem affinity purification/mass-spectrometry-based approach identifies the MCUC protein interaction network. Mitochondrial inner membrane protein EFHD1 interacts with MCUC and inhibits mitochondrial calcium uptake. Loss of MCUB subunit results in an expansion and greater interconnection of the MCU protein network. A dynamic map of the MCUC interaction landscape reveals inhibition of mitochondrial calcium uptake by the mitochondrial intermembrane space protein EFHD1. [ABSTRACT FROM AUTHOR]

Background/Objectives: Neuropathic pain is challenging to treat, often resistant to current therapies, and associated with significant side effects. Pregabalin, an anticonvulsant that modulates calcium channels, is effective but can impair mental and motor functions, especially in older patients. To improve patient outcomes, reducing the doses of pregabalin and combining it with other drugs targeting different neuropathic pain mechanisms may be beneficial. TNF-α blockers such as etanercept have shown potential in addressing neuropathic pain by affecting sodium channels, synaptic transmission, and neuroinflammation. This study evaluates the efficacy and safety of combining low doses of etanercept and pregabalin in allodynia and nociceptive tests. Materials and Methods: Male C57/BL6 mice underwent chronic constriction injury (CCI) of the sciatic nerve to induce neuropathic pain. They were divided into seven groups: sham control, CCI control, low and high doses of pregabalin, low and high doses of etanercept, and a combination of low doses of both drugs. Behavioral tests, including von Frey, hot-plate, and rotarod tests, were used to assess pain responses and motor activity. Results: The results indicated that a high dose of pregabalin significantly reduced mechanical allodynia and thermal hyperalgesia but impaired motor function. Conversely, low doses of etanercept alone had no significant effect. However, the combination of low doses of etanercept (20 mg/kg) and pregabalin (5 mg/kg) effectively alleviated pain without compromising locomotor activity. Conclusions: These results suggest a novel therapeutic strategy for neuropathic pain, enhancing analgesic efficacy while minimizing adverse effects. [ABSTRACT FROM AUTHOR]

Previous studies have observed alterations in excitation–contraction (EC) coupling during end-stage heart failure that include action potential and calcium (Ca2+) transient prolongation and a reduction of the Ca2+ transient amplitude. Underlying these phenomena are the downregulation of potassium (K+) currents, downregulation of the sarcoplasmic reticulum Ca2+ ATPase (SERCA), increase Ca2+ sensitivity of the ryanodine receptor, and the upregulation of the sodium–calcium (Na=-Ca2+) exchanger. However, in human heart failure (HF), debate continues about the relative contributions of the changes in calcium handling vs. the changes in the membrane currents. To understand the consequences of the above changes, they are incorporated into a computational human ventricular myocyte HF model that can explore the contributions of the spontaneous Ca2+ release from the sarcoplasmic reticulum (SR). The reduction of transient outward K+ current (Ito) is the main membrane current contributor to the decrease in RyR2 open probability and L-type calcium channel (LCC) density which emphasizes its importance to phase 1 of the action potential (AP) shape and duration (APD). During current-clamp conditions, RyR2 hyperphosphorylation exhibits the least amount of Ca2+ release from the SR into the cytosol and SR Ca2+ fractional release during a dynamic slow–rapid–slow (0.5–2.5–0.5 Hz) pacing, but it displays the most abundant and more lasting Ca2+ sparks two-fold longer than a normal cell. On the other hand, under voltage-clamp conditions, HF by decreased SERCA and upregulated INCX show the least SR Ca2+ uptake and EC coupling gain, as compared to HF by hyperphosphorylated RyR2s. Overall, this study demonstrates that the (a) combined effect of SERCA and NCX, and the (b) RyR2 dysfunction, along with the downregulation of the cardiomyocyte's potassium currents, could substantially contribute to Ca2+ mishandling at the spark level that leads to heart failure. [ABSTRACT FROM AUTHOR]

Thyroid hormone dysfunction is frequently observed in patients with chronic illnesses including heart failure, which increases the risk of adverse events. This study examined the effects of thyroid hormones (THs) on cardiac transverse-tubule (TT) integrity, Ca2+ sparks, and nanoscale organization of ion channels in excitation-contraction (EC) coupling, including L-type calcium channel (CaV1.2), ryanodine receptor type 2 (RyR2), and junctophilin-2 (Jph2). TH deficiency was established in adult female rats by propyl-thiouracil (PTU) ingestion for 8 wk; followed by randomization to continued PTU without or with oral triiodo- l -thyronine (T3; 10 µg/kg/day) for an additional 2 wk (PTU + T3). Confocal microscopy of isolated cardiomyocytes (CMs) showed significant misalignment of TTs and increased Ca2+ sparks in thyroid-deficient CMs. Density-based spatial clustering of applications with noise (DBSCAN) analysis of stochastic optical reconstruction microscopy (STORM) images showed decreased (P < 0.0001) RyR2 cluster number per cell area in PTU CMs compared with euthyroid (EU) control myocytes, and this was normalized by T3 treatment. CaV1.2 channels and Jph2 localized within a 210 nm radius of the RyR2 clusters were significantly reduced in PTU myocytes, and these values were increased with T3 treatment. A significant percentage of the RyR2 clusters in the PTU myocytes had neither CaV1.2 nor Jph2, suggesting fewer functional clusters in EC coupling. Nearest neighbor distances between RyR2 clusters were greater (P < 0.001) in PTU cells compared with EU- and T3-treated CMs that correspond to disarray of TTs at the sarcomere z-discs. These results support a regulatory role of T3 in the nanoscale organization of RyR2 clusters and colocalization of CaV1.2 and Jph2 in optimizing EC coupling. NEW & NOTEWORTHY: Thyroid hormone (TH) dysfunction exacerbates preexisting heart conditions leading to an increased risk of premature morbidity/mortality. Triiodo- l -thyronine (T3) optimizes cardiac excitation-contraction (EC) coupling by maintaining myocardial T-tubule (TT) structures and organization of calcium ion channels. Single-molecule localization microscopy shows T3 effects on the clustering of ryanodine receptors (RyR2) with colocalization of L-type calcium channels (CaV1.2) and junctophilin-2 (Jph2) at TT-SR structures. Heart disease with subclinical hypothyroidism/low T3 syndrome may benefit from TH treatment. [ABSTRACT FROM AUTHOR]

Elevated global pollution level is the prime reason that contributes to the onset of various harmful health diseases. The products of Biginelli reaction are enormously used in the pharmaceutical industry as they have antiviral, antibacterial, and calcium channel modulation abilities. This work reports a novel eosin Y sensitized boron graphitic carbon nitride (EY‐Ben‐g‐C3N4) as a photocatalyst that efficiently produced 3,4‐dihydropyrimidine‐2‐(1H)‐one by the Biginelli reaction of benzaldehyde, urea, and methyl acetoacetate. The photocatalyst EY‐Ben‐g‐C3N4 showed a successful generation of 3,4‐dihydropyrimidine‐2‐(1H)‐one (Biginelli product) in good yield via photocatalysis which is an eco‐friendly method and has facile operational process. In addition to the production of Biginelli products, the photocatalyst also showed a remarkable NADH regeneration of 81.18%. The incorporation of g‐C3N4 with boron helps increase the surface area and the incorporation of eosin Y which is an inexpensive and non‐toxic dye, and in Ben‐g‐C3N4, enhanced the light‐harvesting capacity of the photocatalyst. The production of 3,4‐dihydropyrimidine‐2‐(1H)‐one and NADH by the EY‐Ben‐g‐C3N4 photocatalyst is attributed to the requisite band gap, high molar absorbance, low rate of charge recombination, and increased capacity of the photocatalyst to harvest solar light energy. [ABSTRACT FROM AUTHOR]

Piezo1 is a Ca2+‐permeable mechanically activated ion channel that is involved in various physiological processes and cellular responses to mechanical stimuli. The study of biophysical characteristics of Piezo1 is important for understanding the mechanisms of its function and regulation. Stretch activation, a routine approach that is applied to stimulate Piezo1 activity in the plasma membrane, has a number of significant limitations that complicate precise single‐channel analysis. Here, we aimed to determine pore properties of native Piezo1, specifically to examine permeation for physiologically relevant signaling divalent ions (calcium and magnesium) in human myeloid leukemia K562 cells using Piezo1‐specific chemical agonist, Yoda1. Using a combination of low‐noise single‐current patch‐clamp recordings of Piezo1 activity in response to Yoda1, we have determined single‐channel characteristics of native Piezo1 under various ionic conditions. Whole‐cell assay allowed us to directly measure Piezo1 single currents carried by Ca2+ or Mg2+ ions in the absence of other permeable cations in the extracellular solutions; unitary conductance values estimated at various concentrations of Mg2+ revealed strong saturation effect. Patch clamp data complemented with fluorescent imaging clearly evidenced Ca2+ and Mg2+ entry via native Piezo1 channel in human leukemia K562 cells. Mg2+ influx via Piezo1 was detected under quasi‐physiological conditions, thus showing that Piezo1 channels could potentially provide the physiological relevant pathway for Mg2+ ion transport and contribute to the regulation of Mg2+‐dependent intracellular signaling. [ABSTRACT FROM AUTHOR]

Hypoxia, or the lack of oxygen, has multiple impacts on the vascular system. The major molecular sensors for hypoxia at the cellular level are hypoxia inducible factor and heme oxygenase. Hypoxia also acts on the vasculature directly conveying its damaging effects through disruption of the control of vascular tone, particularly in the coronary circulation, enhancement of inflammatory responses and activation of coagulation pathways. These effects could be particularly detrimental under pathological conditions such as obstructive sleep apnea and other breathing disorders. Introduction: The effect of conjugate 2-(3,4-Dihydroxyphenyl)-6-{[1-(2'-bromo-3',4'-dimethoxyphenyl)-6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl]methyl}-3,5,7-trihydroxychroman-4-one (DHQ-11) on hypoxia-induced vasorelaxation was investigated in rat aortic rings using standard organ bath techniques. Materials and methods: Hypoxia was stimulated by a superfusion of aortic rings with a glucose-free Krebs solution bubbled with 95% N2/5% CO2. The effect of conjugate DHQ-11 was assessed after a 60-min period of hypoxia on aortic rings precontracted with 50 mM KCl or 1µM phenylephrine (PE). The conjugate DHQ-11 significantly attenuated hypoxia-induced vasorelaxation in the endothelium-intact aortic rings precontracted with KCl or PE in a concentration-dependent manner. Results and discussion: This effect of conjugate DHQ-11 was more potent in aortic rings precontracted with PE than those with KCl where it maximally reduced hypoxia-induced vasorelaxation from 44.7 ± 3.7 to 5.4 ± 3.7 and 33.9 ± 3.4 to 10.8 ± 4.2%, respectively. The removal of the endothelium attenuated the effect of conjugate DHQ-11 on hypoxia-induced vasorelaxation. Similarly, pretreatment of endothelium-intact aortic rings with L-NAME and methylene blue also attenuated the effect of conjugate DHQ-11 on hypoxia-induced vasorelaxation. Furthermore, the blockade of the ATP-sensitive KATP channel with glibenclamide and the calcium-activated large conductance BKCa channel with TEA also significantly attenuated the effect of conjugate DHQ-11 on hypoxia-induced vasorelaxation. Collectively, these results indicated that conjugate DHQ-11 attenuated the hypoxia-induced vasorelaxation suggesting that it alleviated the oxidative damage of vasculature. Conclusions: This effect of conjugate DHQ-11 possible is mediated through several mechanisms including the blockage of the extracellular Ca2+ entry via the voltage-dependent and receptor-operative Ca2+ channels, as well as inhibition of sarcoplasmic reticulum Ca2+ release via the inositol triphosphate pathway. In addition, endothelium and NO/sGC/cGMP/PKG pathway, as well as KATP and BKCa channels most likely participate in protection by conjugate DHQ-11 against hypoxia-induced vasorelaxation. [ABSTRACT FROM AUTHOR]

Spinocerebellar ataxia type 6 (SCA6) is a polyglutamine disorder caused by the expansion of CAG repeats in the gene encoding voltage‐gated calcium channel subunit alpha1 A (CACNA1A). The clinical features of SCA6 include slowly progressive cerebellar ataxia and downbeat positioning nystagmus. The clinical significance of 19 CAG repeats is unclear. We report a case with 19/11 CAG repeats in CACNA1A determined by direct sequencing. The case presented with DPN, which is one of the most important symptoms of SCA6, but did not present with ataxia. [ABSTRACT FROM AUTHOR]

Developmental and Epileptic Encephalopathies (DEEs) represent a clinically and genetically heterogeneous group of rare and severe epilepsies. DEEs commonly begin early in infancy with frequent seizures of various types associated with intellectual disability and leading to a neurodevelopmental delay or regression. Disease-causing genomic variants have been identified in numerous genes and are implicated in over 100 types of DEEs. In this context, genes encoding voltage-gated ion channels (VGCs) play a significant role, and part of the large phenotypic variability observed in DEE patients carrying VGC mutations could be explained by the presence of genetic modifier alleles that can compensate for these mutations. This review will focus on the current knowledge of the compensatory effect of DEE-associated voltage-gated ion channels and their therapeutic implications in DEE. We will enter into detailed considerations regarding the sodium channels SCN1A, SCN2A, and SCN8A; the potassium channels KCNA1, KCNQ2, and KCNT1; and the calcium channels CACNA1A and CACNA1G. [ABSTRACT FROM AUTHOR]

L-type Ca2+ channels (CaV1.2/1.3) convey influx of calcium ions that orchestrate a bevy of biological responses including muscle contraction, neuronal function, and gene transcription. Deficits in CaV1 function play a vital role in cardiac and neurodevelopmental disorders. Here, we develop a genetically encoded enhancer of CaV1.2/1.3 channels (GeeCL) to manipulate Ca2+ entry in distinct physiological settings. We functionalized a nanobody that targets the CaV complex by attaching a minimal effector domain from an endogenous CaV modulator--leucine-rich repeat containing protein 10 (Lrrc10). In cardiomyocytes, GeeCL selectively increased L-type current amplitude. In neurons in vitro and in vivo, GeeCL augmented excitation-transcription (E-T) coupling. In all, GeeCL represents a powerful strategy to boost CaV1.2/1.3 function and lays the groundwork to illuminate insights on neuronal and cardiac physiology and disease. [ABSTRACT FROM AUTHOR]

Cellular senescence is described as an irreversible cell cycle arrest for proliferating cells and is associated with the secretion of senescence associated secretory phenotype factors. It has been known to accumulate with age and is regarded as a key driver of aging‐associated skin pathologies. However, the lack of markers of skin senescence and partially understood skin cellular senescence mechanisms has limited the exploration of skin aging and anti‐skin aging strategies. Recently, intracellular calcium signaling has emerged as an important regulator of cellular senescence and aging. However, little is known about the modulation of skin cellular senescence by calcium‐associated factors. Here, we found that the expression of calcium channel transient receptor potential melastatin 7 (TRPM7) is elevated during skin keratinocyte senescence and aging. Importantly, TRPM7 promotes skin keratinocyte senescence by triggering intracellular calcium transfer from the endoplasmic reticulum to the mitochondria; accumulation of mitochondrial calcium then induces a drop in mitochondrial membrane potential and reactive oxygen species production, leading to subsequent nuclear enlargement and DNA damage. Altogether, these findings indicate that TRPM7 controls skin keratinocyte senescence through regulating intracellular calcium signaling, and thus, shed light on novel strategies for anti‐skin aging therapy. [ABSTRACT FROM AUTHOR]

Transient receptor potential canonical 3 (TRPC3) protein belongs to the TRP family of nonselective cation channels. Its activation occurs by signaling through a G protein‐coupled receptor (GPCR) and a phospholipase C‐dependent (PLC) pathway. Perturbations in the expression of TRPC3 are associated with a plethora of pathophysiological conditions responsible for disorders of the cardiovascular, immune, and central nervous systems. The recently solved cryo‐EM structure of TRPC3 provides detailed inputs about the underlying mechanistic aspects of the channel, which in turn enables more efficient ways of designing small‐molecule modulators. Pharmacologically targeting TRPC3 in animal models has demonstrated great efficacy in treating diseases including cancers, neurological disorders, and cardiovascular diseases. Despite extensive scientific evidence supporting some strong correlations between the expression and activity of TRPC3 and various pathophysiological conditions, therapeutic strategies based on its pharmacological modulations have not led to clinical trials. The development of small‐molecule TRPC3 modulators with high safety, sufficient brain penetration, and acceptable drug‐like profiles remains in progress. Determining the pathological mechanisms for TRPC3 involvement in human diseases and understanding the requirements for a drug‐like TRPC3 modulator will be valuable in advancing small‐molecule therapeutics to future clinical trials. In this review, we provide an overview of the origin and activation mechanism of TRPC3 channels, diseases associated with irregularities in their expression, and new development in small‐molecule modulators as potential therapeutic interventions for treating TRPC3 channelopathies. [ABSTRACT FROM AUTHOR]

Ziconotide is a non-opioid analgesic that acts on N-type voltage-gated calcium channels. Despite its proven effectiveness in pain treatment, it can induce neuropsychiatric symptoms. The aim of this article is to present a case of psychosis secondary to ziconotide and to explore the variety of neuropsychiatric symptoms it produces, exploring the relationship between these symptoms and the mechanism of action of ziconotide. For this purpose, a clinical case is presented as well as a scoping review of other cases published in the scientific literature. A search on Web of Science, Pubmed and Embase databases was performed on December 11, 2023, following the criteria of the PRISMA-ScR Statement. The clinical case presented shows the variety of neuropsychiatric symptomatology that ziconotide can cause in the same patient. On the other hand, 13 papers were retrieved from the scoping review (9 case reports, 4 case series), which included 21 cases of patients treated with ziconotide who presented adverse effects ranging from psychotic symptoms to delirium. In conclusion, the variety of neuropsychiatric symptoms derived from ziconotide could be related to the blockade of N-type voltage-gated calcium channels in glutamatergic and GABAergic neurons, in turn affecting dopaminergic pathways. [ABSTRACT FROM AUTHOR]

We used virus-mediated anterograde and retrograde tracing, optogenetic modulation, immunostaining, in situ hybridization, and patch-clamp recordings in acute brain slices to study the release mechanism and µ-opioid modulation of the dual glutamatergic/GABAergic inputs from the ventral tegmental area and supramammillary nucleus to the granule cells of the dorsal hippocampus of male and female mice. In keeping with previous reports showing that the two transmitters are released by separate active zones within the same terminals, we found that the short-term plasticity and pharmacological modulation of the glutamatergic and GABAergic currents are indistinguishable. We further found that glutamate and GABA release at these synapses are both virtually completely mediated by N- and P/Q-type calcium channels. We then investigated µ-opioid modulation of these synapses and found that activation of µ-opioid receptors (MORs) strongly inhibits the glutamate and GABA release, mostly through inhibition of presynaptic N-type channels. However, the modulation by MORs of these dual synapses is complex, as it likely includes also a disinhibition due to downmodulation of local GABAergic interneurons which make direct axo-axonic contacts with the dual glutamatergic/GABAergic terminals. We discuss how this opioid modulation may enhance LTP at the perforant path inputs, potentially contributing to reinforce memories of drug-associated contexts. [ABSTRACT FROM AUTHOR]

Introduction: Acupoint Catgut Embedding (ACE) is an extended and developed form of traditional acupuncture that serves as a composite stimulation therapy for various diseases. However, its local stimulation effects on acupoints remain unclear. Acupuncture can activate mechanically sensitive calcium ion channels, TRPV2 and TRPV4, located on various cell membranes, promoting Ca2+ influx in acupoint tissues to exert effects. Whether ACE can form mechanical physical stimulation to regulate these channels and the related linkage effect requires validation. Methods: This study investigates the influence of TRPV2 and TRPV4 ion channels on the local stimulation effects of ACE by embedding PGLA suture at the Zusanli (ST36) acupoint in rats and using TRPV2 and TRPV4 inhibitors. Flow cytometry, immunofluorescence, Western blot, and Real-time quantitative PCR were employed to detect intracellular Ca2+ fluorescence intensity, the expression of macrophage (Mac) CD68 and mast cell (MC) tryptase, as well as the protein and mRNA expression of TRPV2 and TRPV4 in acupoint tissues after PGLA embedding. Results: The results indicate that ACE using PGLA suture significantly increases the mRNA and protein expression of TRPV2 and TRPV4, Ca2+ fluorescence intensity, and the expression of Mac CD68 and MC tryptase in acupoint tissues, with these effects diminishing over time. The increasing trends are reduced after using inhibitors, particularly when both inhibitors are used simultaneously. Furthermore, correlation analysis shows that embedding PGLA suture at the ST36 acupoint regulates Mac and MC functions through Ca2+ signaling involving not only TRPV2 and TRPV4 but multiple pathways. Discussion: These results suggest that embedding PGLA suture at the ST36 acupoint generates mechanical physical stimulation and regulates TRPV2 and TRPV4 ion channels, which couple with Ca2+ signaling to form a linkage effect that gradually weakens over time. This provides new reference data for further studies on the stimulation effects and clinical promotion of ACE. [ABSTRACT FROM AUTHOR]

[Display omitted] • Excessive fluoride leads to cognitive impairment of the nervous system. • Excessive fluoride affects cognitive function differently across age groups. • Excessive fluoride reduces cognitive performance in several model organisms. • Excess fluoride impairs cognition by affecting the structure and function of brain. Fluorosis is a global public health concern. Prolonged exposure to excessive fluoride causes fluoride accumulation in the hippocampus, resulting in cognitive dysfunction. Cell death is necessary for maintaining tissue function and morphology, and changes in the external morphology of nerve cells and the function of many internal organelles are typical features of cell death; however, it is also a typical feature of cognitive impairment caused by fluorosis. However, the pathogenesis of cognitive impairment caused by different degrees of fluoride exposure varies. Herein, we provide an overview of cognitive impairment caused by excessive fluoride exposure in different age groups, and the underlying mechanisms for cognitive impairment in various model organisms. The mechanisms underlying these impairments include oxidative stress, synaptic and neurotransmission dysfunction, disruption of mitochondrial and energy metabolism, and calcium channel dysregulation. This study aims to provide potential insights that serve as a reference for subsequent research on the cognitive function caused by excessive fluoride. [ABSTRACT FROM AUTHOR]

K+ secretion in the distal nephron has a critical role in K+ homeostasis and is the primary route by which K+ is lost from the body. Renal K+ secretion is enhanced by increases in dietary K+ intake and by increases in tubular flow rate in the distal nephron. This review addresses new and important insights regarding the mechanisms underlying flow‐induced K+ secretion (FIKS). While basal K+ secretion in the distal nephron is mediated by renal outer medullary K+ (ROMK) channels in principal cells (PCs), FIKS is mediated by large conductance, Ca2+/stretch activated K+ (BK) channels in intercalated cells (ICs), a distinct cell type. BK channel activation requires an increase in intracellular Ca2+ concentration ([Ca2+]i), and both PCs and ICs exhibit increases in [Ca2+]i in response to increases in tubular fluid flow rate, associated with an increase in tubular diameter. PIEZO1, a mechanosensitive, nonselective cation channel, is expressed in the basolateral membranes of PCs and ICs, where it functions as a mechanosensor. The loss of flow‐induced [Ca2+]i transients in ICs and BK channel‐mediated FIKS in microperfused collecting ducts isolated from mice with IC‐specific deletion of Piezo1 in the CCD underscores the importance of PIEZO1 in the renal regulation of K+ transport. [ABSTRACT FROM AUTHOR]

Cyclic nucleotide-gated ion channels (CNGCs) are cell membrane channel proteins for calcium ions. They have been reported to play important roles in survival and in the responses to environmental factors in various plants. However, little is known about the CNGC family and its functions in luffa (Luffa cylindrica L.). In this study, a bioinformatics-based method was used to identify members of the CNGC gene family in L. cylindrica. In total, 20 LcCNGCs were detected, and they were grouped into five subfamilies (I, II, Ⅲ, IV-a, and IV-b) in a phylogenetic analysis with CNGCs from Arabidopsis thaliana (20 AtCNGCs) and Momordica charantia (17 McCNGCs). The 20 LcCNGC genes were unevenly distributed on 11 of the 13 chromosomes in luffa, with none on Chromosomes 1 and 5. The members of each subfamily encoded proteins with highly conserved functional domains. An evolutionary analysis of CNGCs in luffa revealed three gene losses and a motif deletion. An examination of gene replication events during evolution indicated that two tandemly duplicated gene pairs were the primary driving force behind the evolution of the LcCNGC gene family. PlantCARE analyses of the LcCNGC promoter regions revealed various cis-regulatory elements, including those responsive to plant hormones (abscisic acid, methyl jasmonate, and salicylic acid) and abiotic stresses (light, drought, and low temperature). The presence of these cis-acting elements suggested that the encoded CNGC proteins may be involved in stress responses, as well as growth and development. Transcriptome sequencing (RNA-seq) analyses revealed tissue-specific expression patterns of LcCNGCs in various plant parts (roots, stems, leaves, flowers, and fruit) and the upregulation of some LcCNGCs under low-temperature stress. To confirm the accuracy of the RNA-seq data, 10 cold-responsive LcCNGC genes were selected for verification by quantitative real-time polymerase chain reaction (RT-qPCR) analysis. Under cold conditions, LcCNGC4 was highly upregulated (>50-fold increase in its transcript levels), and LcCNGC3, LcCNGC6, and LcCNGC13 were upregulated approximately 10-fold. Our findings provide new information about the evolution of the CNGC family in L. cylindrica and provide insights into the functions of the encoded CNGC proteins. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the effect of rotigaptide (ZP123) on spontaneous contractions of gastric smooth muscle in diabetic rats and explore the underlying mechanisms. Twelve rats were randomly divided into model and normal control groups. Changes in gastric smooth muscle spontaneous contractions in each group were observed. Western blot analysis was performed to detect Cx43 and PKCα expression. Rat gastric smooth muscle cells were cultured in vitro and divided into normal glucose, high glucose and high glucose+rotigaptide group. The intracellular Ca2+ content was observed by immunofluorescence. The amplitude and frequency of gastric smooth muscle spontaneous contractions were reduced in the model group than the normal control group (all p < .01), which were reduced after rotigatide treatment than before treatment in the model group (all p < .01). The model+rotigaptide group showed decreased membrane expression of Cx43, increased cytoplasmic expression of Cx43, increased membrane expression of p‐PKCα Thr497 and lower membrane/cytoplasm ratio of Cx43 expression compared with the model group (all p < .01). The intracellular Ca2+ content was increased in the high glucose group than the normal glucose group (p < .01), while no significant difference was observed between the high glucose+rotigaptide and high glucose groups. Our findings suggest that rotigatide can stabilize the intracellular Ca2+ concentration in gastric smooth muscle cells under high glucose condition by upregulating PKCα activity and downregulating the number of GJs and the opening rate of GJ hemichannels through the PKCα‐Cx43 pathway, thus inhibiting spontaneous contractions of gastric smooth muscle in diabetic rats. [ABSTRACT FROM AUTHOR]