Voltage-gated ion channel's gene expression in the myocardium of embryo and adult chickens.

The functioning of the cardiovascular system is critical for embryo survival. Cardiac contractions depend on the sequential activation of different classes of voltage-gated ion channels. Understanding the fundamental features of these interactions is important for identifying the mechanisms of pathologies development in the myocardium. However, at present there is no consensus on which ion channels are involved in the formation of automaticity in the early embryonic stages. The aim of this study was to elucidate the expression of genes encoding various types of ion channels that are involved in the generation of electrical activity chicken heart at different stages of ontogenesis. We analyzed the expression of 14 genes from different families of ion channels. It was revealed that the expression profiles of ion channel genes change depending on the stages of ontogenesis. The HCN4, CACNA1D, SCN1A, SCN5A, KCNA1 genes have maximum expression at the tubular heart stage. In adult, a switch occurs to the higher expression of CACNA1C, KCNH6, RYR and SLC8A1 genes. This data correlated with the results obtained by the microelectrode method. It can be assumed that the automaticity of the tubular heart is mainly due to the mechanism of the «membrane-clock¼ (hyperpolarization-activated current (If), Ca2+-current L-type (ICaL), Na+-current (INa) and the slow component of the delayed rectifier K+-current (IKs)). Whereas in adult birds, the mechanism for generating electrical impulses is determined by both « membrane- clock¼ and «Ca2+-clock¼.

Identification of a magnesium-binding site at the primary allosteric calcium sensor of the sodium-calcium exchanger: Implications for physiological regulation.

Sodium-calcium exchanger (NCX) proteins are ubiquitously expressed and play a pivotal role in cellular calcium homeostasis by mediating uphill calcium efflux across the cell membrane. Intracellular calcium allosterically regulates the exchange activity by binding to two cytoplasmic calcium-binding domains, CBD1 and CBD2. However, the calcium-binding affinities of these domains are seemingly inadequate to sense physiological calcium oscillations. Previously, magnesium binding to either domain was shown to tune their affinity for calcium, bringing it into the physiological range. However, while the magnesium-binding site of CBD2 was identified, the identity of the CBD1 magnesium site remains elusive. Here, using molecular dynamics in combination with differential scanning fluorimetry and mutational analysis, we pinpoint the magnesium-binding site in CBD1. Specifically, among four calcium-binding sites (Ca1-Ca4) in this domain, only Ca1 can accommodate magnesium with an affinity similar to its free intracellular concentration. Moreover, our results provide mechanistic insights into the modulation of the regulatory calcium affinity by magnesium, which allows an adequate NCX activity level throughout varying physiological needs.

19F-NMR Probing of Ion-Induced Conformational Changes in Detergent-Solubilized and Nanodisc-Reconstituted NCX_Mj.

Consecutive interactions of 3Na+ or 1Ca2+ with the Na+/Ca2+ exchanger (NCX) result in an alternative exposure (access) of the cytosolic and extracellular vestibules to opposite sides of the membrane, where ion-induced transitions between the outward-facing (OF) and inward-facing (IF) conformational states drive a transport cycle. Here, we investigate sub-state populations of apo and ion-bound species in the OF and IF states by analyzing detergent-solubilized and nanodisc-reconstituted preparations of NCX_Mj with 19F-NMR. The 19F probe was covalently attached to the cysteine residues at entry locations of the cytosolic and extracellular vestibules. Multiple sub-states of apo and ion-bound species were observed in nanodisc-reconstituted (but not in detergent-solubilized) NCX_Mj, meaning that the lipid-membrane environment preconditions multiple sub-state populations toward the OF/IF swapping. Most importantly, ion-induced sub-state redistributions occur within each major (OF or IF) state, where sub-state interconversions may precondition the OF/IF swapping. In contrast with large changes in population redistributions, the sum of sub-state populations within each inherent state (OF or IF) remains nearly unchanged upon ion addition. The present findings allow the further elucidation of structure-dynamic modules underlying ion-induced conformational changes that determine a functional asymmetry of ion access/translocation at opposite sides of the membrane and ion transport rates concurring physiological demands.

Impact of RAAS Receptors and Membrane-Bound Transporter System in the Left Ventricle during the Long-Term Control of Hypertension.

The Renin-Angiotensin-Aldosterone System (RAAS) has been implicated in systemic and neurogenic hypertension. The infusion of RAAS inhibitors blunted arterial pressure and efficacy of use-dependent synaptic transmission in sympathetic ganglia. The current investigation aims to elucidate the impact of RAAS-mediated receptors on left ventricular cardiomyocytes and the role of the sarcolemma-bound carrier system in the heart of the hypertensive transgene model. A significant increase in mRNA and the protein expression for angiotensin II (AngII) receptor subtype-1 (AT1R) was observed in (mREN2)27 transgenic compared to the normotensive rodents. Concurrently, there was an upregulation in AT1R and a downregulation in the MAS1 proto-oncogene protein receptor as well as the AngII subtype-2 receptor in hypertensive rodents. There were modifications in the expressions of sarcolemma Na+-K+-ATPase, Na+-Ca2+ exchanger, and Sarcoendoplasmic Reticulum Calcium ATPase in the transgenic hypertensive model. These observations suggest chronic RAAS activation led to a shift in receptor balance favoring augmented cardiac contractility and disruption in calcium handling through modifications of membrane-bound carrier proteins and blood pressure. The study provides insight into mechanisms underlying RAAS-mediated cardiac dysfunction and highlights the potential value of targeting the protective arm of AngII in hypertension.

Effects of hypernatremia on the microglia.

Signs and symptoms of hypernatremia largely indicate central nervous system dysfunction. Acute hypernatremia can cause demyelinating lesions similar to that observed in osmotic demyelination syndrome (ODS). We have previously demonstrated that microglia accumulate in ODS lesions and minocycline protects against ODS by inhibiting microglial activation. However, the direct effect of rapid rise in the sodium concentrations on microglia is largely unknown. In addition, the effect of chronic hypernatremia on microglia also remains elusive. Here, we investigated the effects of acute (6 or 24 h) and chronic (the extracellular sodium concentration was increased gradually for at least 7 days) high sodium concentrations on microglia using the microglial cell line, BV-2. We found that both acute and chronic high sodium concentrations increase NOS2 expression and nitric oxide (NO) production. We also demonstrated that the expression of nuclear factor of activated T-cells-5 (NFAT5) is increased by high sodium concentrations. Furthermore, NFAT5 knockdown suppressed NOS2 expression and NO production. We also demonstrated that high sodium concentrations decreased intracellular Ca2+ concentration and an inhibitor of Na+/Ca2+ exchanger, NCX, suppressed a decrease in intracellular Ca2+ concentrations and NOS2 expression and NO production induced by high sodium concentrations. Furthermore, minocycline inhibited NOS2 expression and NO production induced by high sodium concentrations. These in vitro data suggest that microglial activity in response to high sodium concentrations is regulated by NFAT5 and Ca2+ efflux through NCX and is suppressed by minocycline.

Striatin knock out induces a gain of function of INa and impaired Ca2+ handling in mESC-derived cardiomyocytes.

AIM: Striatin (Strn) is a scaffold protein expressed in cardiomyocytes (CMs) and alteration of its expression are described in various cardiac diseases. However, the alteration underlying its pathogenicity have been poorly investigated. METHODS: We studied the role(s) of cardiac Strn gene (STRN) by comparing the functional properties of CMs, generated from Strn-KO and isogenic WT mouse embryonic stem cell lines. RESULTS: The spontaneous beating rate of Strn-KO CMs was faster than WT cells, and this correlated with a larger fast INa conductance and no changes in If. Paced (2-8 Hz) Strn-KO CMs showed prolonged action potential (AP) duration in comparison with WT CMs and this was not associated with changes in ICaL and IKr. Motion video tracking analysis highlighted an altered contraction in Strn-KO CMs; this was associated with a global increase in intracellular Ca2+, caused by an enhanced late Na+ current density (INaL) and a reduced Na+/Ca2+ exchanger (NCX) activity and expression. Immunofluorescence analysis confirmed the higher Na+ channel expression and a more dynamic microtubule network in Strn-KO CMs than in WT. Indeed, incubation of Strn-KO CMs with the microtubule stabilizer taxol, induced a rescue (downregulation) of INa conductance toward WT levels. CONCLUSION: Loss of STRN alters CMs electrical and contractile profiles and affects cell functionality by a disarrangement of Strn-related multi-protein complexes. This leads to impaired microtubules dynamics and Na+ channels trafficking to the plasma membrane, causing a global Na+ and Ca2+ enhancement.

NCX1/Ca2+ promotes autophagy and decreases bortezomib activity in multiple myeloma through non-canonical NFκB signaling pathway.

Although bortezomib (BTZ) is the cornerstone of anti-multiple myeloma (MM) therapy, the inevitable primary and secondary drug resistance still seriously affects the prognosis of patients. New treatment strategies are in need. Sodium-calcium exchanger 1 (NCX1) is a calcium-permeable ion transporter on the membrane, and our previous studies showed that low NCX1 confers inferior viability in MM cells and suppressed osteoclast differentiation. However, the effect of NCX1 on BTZ sensitivity of MM and its possible mechanism remain unclear. In this study, we investigated the effect of NCX1 on BTZ sensitivity in MM, focusing on cellular processes of autophagy and cell viability. Our results provide evidence that NCX1 expression correlates with MM disease progression and low NCX1 expression increases BTZ sensitivity. NCX1/Ca2+ triggered autophagic flux through non-canonical NFκB pathway in MM cells, leading to attenuated the sensitivity of BTZ. Knockdown or inhibition of NCX1 could potentiate the anti-MM activity of BTZ in vitro and vivo, and inhibition of autophagy sensitized NCX1-overexpressing MM cells to BTZ. In general, this work implicates NCX1 as a potential therapeutic target in MM with BTZ resistance and provides novel mechanistic insights into its vital role in combating BTZ resistance.

Cardiac function is regulated by the sodium-dependent inhibition of the sodium-calcium exchanger NCX1.

The Na+-Ca2+ exchanger (NCX1) is the dominant Ca2+ extrusion mechanism in cardiac myocytes. NCX1 activity is inhibited by intracellular Na+ via a process known as Na+-dependent inactivation. A central question is whether this inactivation plays a physiological role in heart function. Using CRISPR/Cas9, we inserted the K229Q mutation in the gene (Slc8a1) encoding for NCX1. This mutation removes the Na+-dependent inactivation while preserving transport properties and other allosteric regulations. NCX1 mRNA levels, protein expression, and protein localization are unchanged in K229Q male mice. However, they exhibit reduced left ventricular ejection fraction and fractional shortening, while displaying a prolonged QT interval. K229Q ventricular myocytes show enhanced NCX1 activity, resulting in action potential prolongation, higher incidence of aberrant action potentials, a faster decline of Ca2+ transients, and depressed cell shortening. The results demonstrate that NCX1 Na+-dependent inactivation plays an essential role in heart function by affecting both cardiac excitability and contractility.

Rise of palmitoylation: A new trick to tune NCX1 activity.

The cardiac Na+/Ca2+ Exchanger (NCX1) controls transmembrane calcium flux in numerous tissues. The only reversible post-translational modification established to regulate NCX1 is palmitoylation, which alters the ability of the exchanger to inactivate. Palmitoylation creates a binding site for the endogenous XIP domain, a region of the NCX1 intracellular loop established to inactivate NCX1. The binding site created by NCX1 palmitoylation sensitizes the transporter to XIP. Herein we summarize our recent knowledge on NCX1 palmitoylation and its association with cardiac pathologies, and discuss these findings in the light of the recent cryo-EM structures of human NCX1.

Cardiac-Specific Deletion of Scn8a Mitigates Dravet Syndrome-Associated Sudden Death in Adults.

BACKGROUND: Sudden unexpected death in epilepsy (SUDEP) is a fatal complication experienced by otherwise healthy epilepsy patients. Dravet syndrome (DS) is an inherited epileptic disorder resulting from loss of function of the voltage-gated sodium channel, NaV 1.1, and is associated with particularly high SUDEP risk. Evidence is mounting that NaVs abundant in the brain also occur in the heart, suggesting that the very molecular mechanisms underlying epilepsy could also precipitate cardiac arrhythmias and sudden death. Despite marked reduction of NaV 1.1 functional expression in DS, pathogenic late sodium current (INa,L) is paradoxically increased in DS hearts. However, the mechanisms by which DS directly impacts the heart to promote sudden death remain unclear. OBJECTIVES: In this study, the authors sought to provide evidence implicating remodeling of Na+ - and Ca2+ -handling machinery, including NaV 1.6 and Na+/Ca2+exchanger (NCX) within transverse (T)-tubules in DS-associated arrhythmias. METHODS: The authors undertook scanning ion conductance microscopy (SICM)-guided patch clamp, super-resolution microscopy, confocal Ca2+ imaging, and in vivo electrocardiography studies in Scn1a haploinsufficient murine model of DS. RESULTS: DS promotes INa,L in T-tubular nanodomains, but not in other subcellular regions. Consistent with increased NaV activity in these regions, super-resolution microscopy revealed increased NaV 1.6 density near Ca2+release channels, the ryanodine receptors (RyR2) and NCX in DS relative to WT hearts. The resulting INa,L in these regions promoted aberrant Ca2+ release, leading to ventricular arrhythmias in vivo. Cardiac-specific deletion of NaV 1.6 protects adult DS mice from increased T-tubular late NaV activity and the resulting arrhythmias, as well as sudden death. CONCLUSIONS: These data demonstrate that NaV 1.6 undergoes remodeling within T-tubules of adult DS hearts serving as a substrate for Ca2+ -mediated cardiac arrhythmias and may be a druggable target for the prevention of SUDEP in adult DS subjects.

The protective effects of gallic acid and SGK1 inhibitor on cardiac damage and genes involved in Ca2+ homeostasis in an isolated heart model of ischemia/reperfusion injury in rat.

Serum and glucocorticoid-induced kinase 1 (SGK1) is an enzyme that may play a vital role in myocardial ischemia/reperfusion (I/R) injury. This enzyme may affect sarcoplasmic reticulum Ca2+ ATPase (SERCA2), ryanodine receptor (RyR2) and sodium/calcium exchanger (NCX1) during myocardial ischemia/reperfusion injury. The objective of this investigation was to analyze the effects of the combination of GSK650394 (SGK1 inhibitor) and gallic acid on the calcium ions regulation, inflammation, and cardiac dysfunction resulting from ischemia/reperfusion (I/R) injury in the heart. Sixty male Wistar rats were randomly divided into six groups, pretreated with gallic acid or vehicle for 10 days. Then the heart was isolated and exposed to I/R. In the SGK1 inhibitor groups, GSK650394 was infused 5 min before ischemia induction. After that, Ca2+ homeostasis, inflammatory factors, cardiac function, antioxidant activity, and myocardial damage were evaluated. The findings suggested that the use of two drugs in combination therapy produced more significant improvements in left ventricular end diastolic pressure, left ventricular systolic pressure, RR-interval, ST-elevation, inflammation factors, and antioxidant enzymes activity as compared to the use of each drug. Despite this, there was a significant decrease observed in heart marker enzymes (including lactate dehydrogenase (LDH), troponin-I (cTn-I), creatine kinase-MB (CK-MB) and creatine phosphokinase (CPK) when compared to the ischemic group. Additionally, the expression of RyR2, NCX1, and SERCA2 genes showed a noteworthy increase as compared to the ischemic group. The findings of this study propose that using both of these agents on myocardial I/R injury could have superior advantages compared to using only one of them.

Neuronal and astrocyte NCX isoform/splice variants: How do they participate in Na+ and Ca2+ signalling?

NCX1, NCX2, and NCX3 gene isoforms and their splice variants are characteristically expressed in different regions of the brain. The tissue-specific splice variants of NCX1-3 isoforms show specific expression profiles in neurons and astrocytes, whereas the relevant NCX isoform/splice variants exhibit diverse allosteric modes of Na+- and Ca2+-dependent regulation. In general, overexpression of NCX1-3 genes leads to neuroprotective effects, whereas their ablation gains the opposite results. At this end, the partial contributions of NCX isoform/splice variants to neuroprotective effects remain unresolved. The glutamate-dependent Na+ entry generates Na+ transients (in response to neuronal cell activities), whereas the Na+-driven Ca2+ entry (through the reverse NCX mode) raises Ca2+ transients. This special mode of signal coupling translates Na+ transients into the Ca2+ signals while being a part of synaptic neurotransmission. This mechanism is of general interest since disease-related conditions (ischemia, metabolic stress, and stroke among many others) trigger Na+ and Ca2+ overload with deadly outcomes of downstream apoptosis and excitotoxicity. The recently discovered mechanisms of NCX allosteric regulation indicate that some NCX variants might play a critical role in the dynamic coupling of Na+-driven Ca2+ entry. In contrast, the others are less important or even could be dangerous under altered conditions (e.g., metabolic stress). This working hypothesis can be tested by applying advanced experimental approaches and highly focused computational simulations. This may allow the development of structure-based blockers/activators that can selectively modulate predefined NCX variants to lessen the life-threatening outcomes of excitotoxicity, ischemia, apoptosis, metabolic deprivation, brain injury, and stroke.

NLRP14 Safeguards Calcium Homeostasis via Regulating the K27 Ubiquitination of Nclx in Oocyte-to-Embryo Transition.

Sperm-induced Ca2+ rise is critical for driving oocyte activation and subsequent embryonic development, but little is known about how lasting Ca2+ oscillations are regulated. Here it is shown that NLRP14, a maternal effect factor, is essential for keeping Ca2+ oscillations and early embryonic development. Few embryos lacking maternal NLRP14 can develop beyond the 2-cell stage. The impaired developmental potential of Nlrp14-deficient oocytes is mainly caused by disrupted cytoplasmic function and calcium homeostasis due to altered mitochondrial distribution, morphology, and activity since the calcium oscillations and development of Nlrp14-deficient oocytes can be rescued by substitution of whole cytoplasm by spindle transfer. Proteomics analysis reveal that cytoplasmic UHRF1 (ubiquitin-like, containing PHD and RING finger domains 1) is significantly decreased in Nlrp14-deficient oocytes, and Uhrf1-deficient oocytes also show disrupted calcium homeostasis and developmental arrest. Strikingly, it is found that the mitochondrial Na+ /Ca2+ exchanger (NCLX) encoded by Slc8b1 is significantly decreased in the Nlrp14mNull oocyte. Mechanistically, NLRP14 interacts with the NCLX intrinsically disordered regions (IDRs) domain and maintain its stability by regulating the K27-linked ubiquitination. Thus, the study reveals NLRP14 as a crucial player in calcium homeostasis that is important for early embryonic development.

Inhibition of Acid-Sensing Ion Channels by KB-R7943, a Reverse Na+/Ca2+ Exchanger Inhibitor.

KB-R7943, an isothiourea derivative, is widely used as a pharmacological inhibitor of reverse sodium-calcium exchanger (NCX). It has been shown to have neuroprotective and analgesic effects in animal models; however, the detailed molecular mechanisms remain elusive. In the current study, we investigated whether KB-R7943 modulates acid-sensing ion channels (ASICs), a group of proton-gated cation channels implicated in the pathophysiology of various neurological disorders, using the whole-cell patch clamp techniques. Our data show that KB-R7943 irreversibly inhibits homomeric ASIC1a channels heterologously expressed in Chinese Hamster Ovary (CHO) cells in a use- and concentration-dependent manner. It also reversibly inhibits homomeric ASIC2a and ASIC3 channels in CHO cells. Both the transient and sustained current components of ASIC3 are inhibited. Furthermore, KB-R7943 inhibits ASICs in primary cultured peripheral and central neurons. It inhibits the ASIC-like currents in mouse dorsal root ganglion (DRG) neurons and the ASIC1a-like currents in mouse cortical neurons. The inhibition of the ASIC1a-like current is use-dependent and unrelated to its effect on NCX since neither of the other two well-characterized NCX inhibitors, including SEA0400 and SN-6, shows an effect on ASIC. Our data also suggest that the isothiourea group, which is lacking in other structurally related analogs that do not affect ASIC1a-like current, may serve as a critical functional group. In summary, we characterize KB-R7943 as a new ASIC inhibitor. It provides a novel pharmacological tool for the investigation of the functions of ASICs and could serve as a lead compound for developing small-molecule drugs for treating ASIC-related disorders.

Silencing mouse circular RNA circSlc8a1 by circular antisense cA-circSlc8a1 induces cardiac hepatopathy.

Circular RNAs (circRNAs) are a group of non-coding RNAs with a unique circular structure generated by back-splicing. It is acknowledged that circRNAs play critical roles in cardiovascular diseases. However, functional studies of circRNAs were impeded due to lack of effective in vivo silencing approaches. Since most circRNAs are produced by protein-coding transcripts, gene editing typically affects the coding activity of the parental genes. In this study, we developed a circular antisense RNA (cA-circSlc8a1) that could silence the highly expressed circRNA circSlc8a1 in the mouse heart but not its parental Slc8a1 linear mRNA. Transgenic cA-circSlc8a1 mice developed congestive heart failure resulting in a significant increase in the body weight secondary to peripheral edema and congestive hepatopathy. To further test the role of circSlc8a1, we generated transgenic mice overexpressing circSlc8a1 and observed a protective effect of circSlc8a1 in a pressure overload model. Mechanistically, we found that circSlc8a1 translocated into mitochondria to drive ATP synthesis. While establishing a transgenic murine model for antisense-mediated circRNA silencing without interfering with the parental linear RNA, our finding revealed the essential role of circSlc8a1 in maintaining heart function and may lay the groundwork of using the circular antisense RNA as a potential gene therapy approach for cardiovascular diseases.

Mitochondrial sodium/calcium exchanger NCLX regulates glycolysis in astrocytes, impacting on cognitive performance.

Intracellular Ca2+ concentrations are strictly controlled by plasma membrane transporters, the endoplasmic reticulum, and mitochondria, in which Ca2+ uptake is mediated by the mitochondrial calcium uniporter complex (MCUc), while efflux occurs mainly through the mitochondrial Na+ /Ca2+ exchanger (NCLX). RNAseq database repository searches led us to identify the Nclx transcript as highly enriched in astrocytes when compared with neurons. To assess the role of NCLX in mouse primary culture astrocytes, we inhibited its function both pharmacologically or genetically. This resulted in re-shaping of cytosolic Ca2+ signaling and a metabolic shift that increased glycolytic flux and lactate secretion in a Ca2+ -dependent manner. Interestingly, in vivo genetic deletion of NCLX in hippocampal astrocytes improved cognitive performance in behavioral tasks, whereas hippocampal neuron-specific deletion of NCLX impaired cognitive performance. These results unveil a role for NCLX as a novel modulator of astrocytic glucose metabolism, impacting on cognition.

Real time monitoring of cold Ca2+ dependent transcription and its modulation by NCX inhibitors.

Real-time monitoring of cellular temperature responses is an important technique in thermal biology and drug development. Recent study identified that Na+/Ca2+ exchanger (NCX)-dependent Ca2+ influx transduces cold signals to circadian clock in mammalian cultured cells. The finding raised an idea that cellular responses to the cold signals can be analyzed by monitoring of clock gene expression. We found that Per1 and Per2 were up-regulated after culture at 27 °C compared to 37 °C in Rat-1 fibroblasts. In order to monitor cold-Ca2+-dependent transcription in living cells, we developed a luciferase-based real-time reporting system by using Per1 promoter, Per2 promoter, Ca2+/cAMP-response elements (CRE) or NFAT-binding elements. We found that benzyloxyphenyl NCX inhibitor KB-R7943 and SN-6, but not SEA-0400 or YM-244769 inhibited the cold induction of Per2. Our study established a real-time monitoring system for cold Ca2+ signaling which can be applied to evaluation of drugs.

The airway smooth muscle sodium/calcium exchanger NCLX is critical for airway remodeling and hyperresponsiveness in asthma.

The structural changes of airway smooth muscle (ASM) that characterize airway remodeling (AR) are crucial to the pathogenesis of asthma. During AR, ASM cells dedifferentiate from a quiescent to a proliferative, migratory, and secretory phenotype. Calcium (Ca2+) is a ubiquitous second messenger that regulates many cellular processes, including proliferation, migration, contraction, and metabolism. Furthermore, mitochondria have emerged as major Ca2+ signaling organelles that buffer Ca2+ through uptake by the mitochondrial Ca2+ uniporter and extrude it through the Na+/Ca2+ exchanger (NCLX/Slc8b1). Here, we show using mitochondrial Ca2+-sensitive dyes that NCLX only partially contributes to mitochondrial Ca2+ extrusion in ASM cells. Yet, NCLX is necessary for ASM cell proliferation and migration. Through cellular imaging, RNA-Seq, and biochemical assays, we demonstrate that NCLX regulates these processes by preventing mitochondrial Ca2+ overload and supporting store-operated Ca2+ entry, activation of Ca2+/calmodulin-dependent kinase II, and transcriptional and metabolic reprogramming. Using small animal respiratory mechanic measurements and immunohistochemistry, we show that smooth muscle-specific NCLX KO mice are protected against AR, fibrosis, and hyperresponsiveness in an experimental model of asthma. Our findings support NCLX as a potential therapeutic target in the treatment of asthma.

Silencing lncRNA 93358 Inhibits the Apoptosis of Myocardial Cells in Myocardial Infarction Rats by Inducing the Expression of SLC8A1.

Objective: To explore the inhibitor effects and mechanism of lncRNA 93358 against the apoptosis of myocardial cells in rats with myocardial infarction. Methods: The myocardial infarction model was established in rats, which were identified by cardiac ultrasound. TTC staining was used to evaluate the degree of heart infarction, and HE staining was utilized to determine the pathological state in myocardial tissues. The apoptotic state in myocardial tissues was confirmed by TUNEL assay. lncRNA 93358 was screened out using a high-throughput sequencing which was confirmed by RT-qPCR. The interaction between miR-466c-3p and SLC8A1 was identified using the dual-luciferase reporter assay. The expression level of Bax, Bcl-2, and SLC8A1 was determined in lncRNA 93358 knockdown cells using RT-qPCR and Western blotting. Results: Massive myocardial necrosis was observed in model rats according to the results of TTC staining, HE staining, and TUNEL assay. lncRNA 93358 and Bax were found significantly upregulated, and Bcl-2 and SLC8A1 were greatly downregulated in model rats, which were dramatically reversed by the knockdown of lncRNA 93358, accompanied by the decline area of myocardial necrosis and decreased apoptotic myocardial cells. Conclusion: Silencing lncRNA 93358 inhibits the apoptosis of myocardial cells in rats with myocardial infarction by inducing the expression of SLC8A1.