Search

Background and Purpose: Excitotoxicity due to mitochondrial calcium (Ca2+) overloading can trigger neuronal cell death in a variety of pathologies. Inhibiting the mitochondrial calcium uniporter (MCU) has been proposed as a therapeutic avenue to prevent calcium overloading. Ru265 (ClRu(NH3)4(μ‐N)Ru(NH3)4Cl]Cl3) is a cell‐permeable inhibitor of the mitochondrial calcium uniporter (MCU) with nanomolar affinity. Ru265 reduces sensorimotor deficits and neuronal death in models of ischemic stroke. However, the therapeutic use of Ru265 is limited by the induction of seizure‐like behaviours. Experimental Approach: We examined the effect of Ru265 on synaptic and neuronal function in acute brain slices and hippocampal neuron cultures derived from mice, in control and where MCU expression was genetically abrogated. Key Results: Ru265 decreased evoked responses from calyx terminals and induced spontaneous action potential firing of both the terminal and postsynaptic principal cell. Recordings of presynaptic Ca2+ currents suggested that Ru265 blocks the P/Q type channel, confirmed by the inhibition of currents in cells exogenously expressing the P/Q type channel. Measurements of presynaptic K+ currents further revealed that Ru265 blocked a KCNQ current, leading to increased membrane excitability, underlying spontaneous spiking. Ca2+ imaging of hippocampal neurons showed that Ru265 increased synchronized, high‐amplitude events, recapitulating seizure‐like activity seen in vivo. Importantly, MCU ablation did not suppress Ru265‐induced increases in neuronal activity and seizures. Conclusions and Implications: Our findings provide a mechanistic explanation for the pro‐convulsant effects of Ru265 and suggest counter screening assays based on the measurement of P/Q and KCNQ channel currents to identify safe MCU inhibitors. [ABSTRACT FROM AUTHOR]

Calcium ions (Ca2+) participate in the regulation of cellular apoptosis as a second messenger. Calcium overload, which refers to the abnormal elevation of intracellular Ca2+ concentration, is a factor that can lead to cell death. Here, based on the unique biological effects of Ca2+, hollow mesoporous calcium peroxide nanoparticles (HMCPN) were developed by a facile hydrolysis-precipitation method for drug-free tumor calcicoptosis therapy. The average pore size of the optimized HMCPN17 is 6.4 nm, and the surface area is 81.3 m2/g, which enables HMCPN17 with high drug loading capability. The Ca2+ release from HMCPN17 is much faster at pH 6.8 than that at pH 7.4, which can be ascribed to the acid-triggered conversion of HMCPN17 to Ca2+ and H 2 O 2 , indicating a pH-responsive decomposition behavior of HMCPN17. The high drug loading contents of doxorubicin (DOX) and/or sorafenib (SFN) indicate that HMCPN17 can be employed as a generic drug delivery system (DDS). The in vitro and in vivo results reinforce the high calcicoptosis therapeutic efficacy of tumors by our HMCPN17 without drug loading, which can be attributed to the efficient accumulation in tumors and the ability of H 2 O 2 and Ca2+ production at acidic TME. Our HMCPN17 has broad application prospect for construction of multi-drug-loaded composite nanomaterials with diversified functions for the treatment of tumors. The combination of hollow mesoporous nanomaterials and calcium peroxide nanoparticles has a wide range of applications in the synergistic treatment of tumors. In this study, hollow mesoporous calcium peroxide nanoparticles (HMCPN) were developed based on a simple hydrolysis-precipitation method for tumor calcicoptosis therapy without drug loading. The high drug loading contents of DOX and/or SFN indicate that our HMCPN can serve as a generic DDS. The experimental results demonstrated the high calcicoptosis therapeutic efficacy of HMCPN on tumors even without drug loading. [Display omitted] [ABSTRACT FROM AUTHOR]

Defects in chaperone-mediated autophagy (CMA) are associated with cellular senescence, but the mechanism remains poorly understood. Here, we found that CMA inhibition induced cellular senescence in a calcium-dependent manner and identified its role in TNF-induced senescence of nucleus pulposus cells (NPC) and intervertebral disc degeneration. Based on structural and functional proteomic screens, PLCG1 (phospholipase C gamma 1) was predicted as a potential substrate for CMA deficiency to affect calcium homeostasis. We further confirmed that PLCG1 was a key mediator of CMA in the regulation of intracellular calcium flux. Aberrant accumulation of PLCG1 caused by CMA blockage resulted in calcium overload, thereby inducing NPC senescence. Immunoassays on human specimens showed that reduced LAMP2A, the rate-limiting protein of CMA, or increased PLCG1 was associated with disc senescence, and the TNF-induced disc degeneration in rats was inhibited by overexpression of Lamp2a or knockdown of Plcg1. Because CMA dysregulation, calcium overload, and cellular senescence are common features of disc degeneration and other age-related degenerative diseases, the discovery of actionable molecular targets that can link these perturbations may have therapeutic value.Abbreviation: ATRA: all-trans-retinoic acid; BrdU: bromodeoxyuridine; CDKN1A/p21: cyclin dependent kinase inhibitor 1A; CDKN2A/p16-INK4A: cyclin dependent kinase inhibitor 2A; CMA: chaperone-mediated autophagy; DHI: disc height index; ER: endoplasmic reticulum; IP: immunoprecipitation; IP3: inositol 1,4,5-trisphosphate; ITPR/IP3R: inositol 1,4,5-trisphosphate receptor; IVD: intervertebral disc; IVDD: intervertebral disc degeneration; KD: knockdown; KO: knockout; Leu: leupeptin; MRI: magnetic resonance imaging; MS: mass spectrometry; N/L: NH4Cl and leupeptin; NP: nucleus pulposus; NPC: nucleus pulposus cells; PI: protease inhibitors; PLC: phospholipase C; PLCG1: phospholipase C gamma 1; ROS: reactive oxygen species; RT-qPCR: real-time quantitative reverse transcription PCR; SA-GLB1/β-gal: senescence-associated galactosidase beta 1; SASP: senescence-associated secretory phenotype; STV: starvation; TMT: tandem mass tag; TNF: tumor necrosis factor; TP53: tumor protein p53; UPS: ubiquitin-proteasome system. [ABSTRACT FROM AUTHOR]

[Display omitted] Targeted breast cancer therapies hold the potential to improve the efficiency of drug delivery to the pathology site without impacting the viability and function of healthy cells. Herein, we developed multifunctional nanocarriers that target simultaneously several downstream signaling processes in triple negative breast cancer cells. The system comprises pH sensitive CaCO 3 nanoparticles (NPs) as carriers of the anticancer drug doxorubicin (DOX). The NPs were coated in a layer-by-layer (LbL) fashion using poly- l -lysine and hyaluronic acid to target receptors overexpressed in breast cancer (e.g. CD44, RHAMM). Spheroids of the triple-negative Hs578T cell line were used as a 3D model to assess the therapeutic potential of this system. Our results showed that the NPs act via a synergistic mechanism that combines Ca2+ overload causing cell calcification and DNA damage by DOX. The LbL coating was crucial for the protection of the healthy cells, i.e. it provides NPs with targeting capacity. The overall data suggests that the LbL-coated NPs loaded with DOX hold great potential for the treatment of breast cancer. [ABSTRACT FROM AUTHOR]

Boye Zhang,1,2 Jianliang Man,3,4 Lingyun Guo,1 Xiaoxia Ru,1 Chengwu Zhang,1,2 Wen Liu,1,2,5 Lihong Li,1,2,5 Sufang Ma,1,2 Lixia Guo,2,4 Haojiang Wang,1,2 Bin Wang,1,2 Haipeng Diao,1,5 Renchao Che,6,7 Lili Yan1,2,5 1School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, 030001, People’s Republic of China; 2Shanxi Province Brain Degenerative Diseases Precision Diagnosis and Treatment Engineering Research Center, Shanxi Medical University, Jinzhong, 030606, People’s Republic of China; 3Academy of Medical Sciences, Shanxi Medical University, Taiyuan, 030001, People’s Republic of China; 4College of Pharmacy, Shanxi Medical University, Taiyuan, 030001, People’s Republic of China; 5Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, 030001, People’s Republic of China; 6Laboratory of Advanced Materials, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Academy for Engineering &Technology, Fudan University, Shanghai, 200438, People’s Republic of China; 7Zhejiang Laboratory, Hangzhou, 311100, People’s Republic of ChinaCorrespondence: Lili Yan; Renchao Che, Email yanlili@sxmu.edu.cn; rcche@fudan.edu.cnBackground: Challenges such as poor drug selectivity, non-target reactivity, and the development of drug resistance continue to pose significant obstacles in the clinical application of cancer therapeutic drugs. To overcome the limitations of drug resistance in chemotherapy, a viable treatment strategy involves designing multifunctional nano-platforms that exploit the unique physicochemical properties of tumor microenvironment (TME).Methods: Herein, layer-by-layer nanoparticles with polyporous CuS as delivery vehicles, loaded with a sonosensitizer (tetra-(4-aminophenyl) porphyrin, TAPP) and sequentially functionalized with pH‐responsive CaCO3, targeting group hyaluronic acid (HA) were designed and synthesized for synergistic treatment involving chemodynamic therapy (CDT), sonodynamic therapy (SDT), photothermal therapy (PTT), and calcium overload. Upon cleavage in an acidic environment, CaCO3 nanoparticles released TAPP and Ca2+, with TAPP generating 1O2 under ultrasound trigger. Exposed CuS produced highly cytotoxic ·OH in response to H2O2 and also exhibited a strong PTT effect.Results: CuS@TAPP-CaCO3/HA (CTCH) delivered an enhanced ability to release more Ca2+ under acidic conditions with a pH value of 6.5, which in situ causes damage to HeLa mitochondria. In vitro and in vivo experiments both demonstrated that mitochondrial dysfunction greatly amplified the damage caused by reactive oxygen species (ROS) to tumor, which strongly confirms the synergistic effect between calcium overload and reactive oxygen therapy.Conclusion: Collectively, the development of CTCH presents a novel therapeutic strategy for tumor treatment by effectively responding to the acidic TME, thus holding significant clinical implications.Keywords: mitochondria damage, calcium overload, reactive oxygen oncotherapy, pH-responsive, synergistic treatment

Immunogenic cell death (ICD) induced by calcium ion (Ca2+) overload has attracted significant attention owing to its ability to activate the immune system and generate durable antitumor immune responses. However, the slow release of Ca2+ by commonly used nanomodulators provides tumor cells with the opportunity to efficiently eliminate excess Ca2+ through ion channels, thus diminishing the therapeutic efficacy. Consequently, it is crucial to explore strategies for rapid Ca2+ release. To address this issue, a glutathione‐triggered Ca(IO3)2@starch‐based Ca2+ nanobomb is presented. This nanobomb not only enables accurate and efficient Ca2+ delivery to the tumor site but also exploits glutathione‐triggered photoacoustic (PA) imaging‐guided photothermal precise control of TRPV1 ion channel activation for enhancing the Ca2+ influx. Both in vitro and in vivo results confirm that the photothermally regulated Ca2+ influx based on this Ca2+ nanobomb effectively promotes ICD and stimulates immune infiltration in tumor tissues, ultimately leading to the effective inhibition of tumor growth and metastasis. The developed Ca2+ nanobomb presents a potential strategy to enhance ICD based on Ca2+ overload, thus addressing the challenges associated with precise and timely regulation of Ca2+ influx and offering prospects for improved antitumor immunotherapy. [ABSTRACT FROM AUTHOR]

Objective To evaluate the effect of glycogen synthase kinase 3β (GSK3β) on hypoxia/reoxygenation (H/R)-induced injury of senescent renal tubular epithelial cell (RTEC) in aged mice and its regulatory mechanism. Methods RTEC were divided into the Young group (young RTEC with normal growth), Old group (aged RTEC induced by Etoposide), Old+Ad-shNC+H/R group [aged RTEC induced by Etoposide and then transfected with adenovirus negative control (Ad-shNC) for H/R treatment], and Old+Ad-shGSK3β+H/R group (aged RTEC induced by Etoposide and then transfected with short-hairpin RNA-expressing adenovirus with targeted silencing GSK3β for H/R treatment), respectively. Apoptosis level and mitochondrial reactive oxygen species level were detected by flow cytometry. Calcium ion level was determined by immunofluorescence staining. The expression and phosphorylation levels of GSK3β, mitochondria-associated endoplasmic reticulum membrane (MAM)-related proteins of inositol 1,4,5-trisphosphate receptor1 (ITPR1), voltage dependent anion-selective channel 1(VDAC1) and glucose-regulated protein 75 (GRP75) were detected by Western blot. The interaction between GSK3β and MAM-related proteins was analyzed by immunoprecipitation. Results Compared with the Young group, the apoptosis, mitochondrial reactive oxygen species and mitochondrial calcium ion levels were higher in the Old group. Compared with the Old group, the apoptosis, mitochondrial reactive oxygen species and mitochondrial calcium ion levels were higher in the Old+Ad-shNC+H/R group. Compared with the Old+Ad-shNC+H/R group, the apoptosis, mitochondrial reactive oxygen species and mitochondrial calcium ion levels were lower in the Old+Ad-shGSK3β+H/R group, and the differences were statistically significant (all P<0.05). Compared with the Young group, the expression levels of ITPR1, GRP75 and GSK3β proteins were up-regulated, the phosphorylation levels of ITPR1 and GRP75 were increased, whereas the total protein and phosphorylation levels of VDAC1 were decreased in the Old group. Compared with the Old group, the expression level of GSK3β protein was unchanged, the total protein and phosphorylation levels of ITPR1 and GRP75 were increased, the expression level of total VDAC1 protein remained unchanged and the phosphorylation level was increased in the Old+Ad-shNC+H/R group. Compared with the Old+Ad-shNC+H/R group, the expression level of GSK3β protein was decreased, the expression levels of total ITPR1, GRP75 and VDAC1 proteins were unchanged, whereas the phosphorylation levels were decreased in the Old+Ad-shGSK3β+H/R group. Immunoprecipitation showed that GSK3β could interact with ITPR1, GRP75 and VDAC1 proteins.Conclusions The expression level of GSK3β is up-regulated in senescent RTEC. Down-regulating GSK3β expression may reduce the phosphorylation level of ITPR1-GRP75-VDAC1 complex, constrain the overload of mitochondrial calcium ion, protect mitochondrial function and mitigate cell damage during reperfusion. [ABSTRACT FROM AUTHOR]

ABSTRACT This article describes the case of a 40‐year‐old individual who presented with fulminant myocarditis. Initial ECG displayed sinus tachycardia with a heart rate of 117 bpm, QS complexes in leads V1–V3, ST‐segment depression in leads II, III, aVF, V5–V6, and ST‐segment elevation >0.2 mV in leads V1 through V3. The initial clinical assessment suggested an acute anteroseptal myocardial infarction. However, subsequent diagnostic evaluation through coronary angiography disclosed that the coronary arteries were normal. Therefore, clinicians should carefully consider the differential diagnosis between these conditions, as their management strategies differ markedly. Two hours after admission, the patient unexpectedly developed syncope. The ECG findings were consistent with the typical characteristics of bidirectional ventricular tachycardia. Our report described the appearance and morphology as well as mechanism of bidirectional ventricular tachycardia in detail. Additionally, we delineate differential diagnoses for disease that can cause bidirectional ventricular tachycardia, such as aconite poisoning, digoxin overdose, immune checkpoint inhibitor (ICI), myocardial ischemia, and hereditary channelopathies, such as catecholaminergic polymorphic ventricular tachycardia (CPVT) and Andersen–Tawil syndrome. Therefore, clinicians should recognize this ECG finding immediately and initiate appropriate treatment promptly as these measures may be vital in saving the patient's life.

Evodiamine (EVO), the main active alkaloid in Evodia rutaecarpa, was shown to exert various pharmacological activities, especially anti-tumor. Currently, it is considered a potential anti-cancer drug due to its excellent anti-tumor activity, which unfortunately has adverse reactions, such as the risk of liver and kidney injury, when Evodia rutaecarpa containing EVO is used clinically. In the present study, we aim to clarify the potential toxic target organs and toxicity mechanism of EVO, an active monomer in Evodia rutaecarpa, and to develop mitigation strategies for its toxicity mechanism. Transcriptome analysis and related experiments showed that the PI3K/Akt pathway induced by calcium overload was an important step in EVO-induced apoptosis of renal cells. Specifically, intracellular calcium ions were increased, and mitochondrial calcium ions were decreased. In addition, EVO-induced calcium overload was associated with TRPV1 receptor activation. In vivo TRPV1 antagonist and calcium chelator effects were observed to significantly reduce body weight loss and renal damage in mice due to EVO toxicity. The potential nephrotoxicity of EVO was further confirmed by an in vivo test. In conclusion, TRPV1-mediated calcium overload-induced apoptosis is one of the mechanisms contributing to the nephrotoxicity of EVO due to its toxicity, whereas maintaining body calcium homeostasis is an effective measure to reduce toxicity. These studies suggest that the clinical use of EVO-containing herbal medicines should pay due attention to the changes in renal function of patients as well as the off-target effects of the drugs.

Sonodynamic therapy (SDT) is an emerging cancer treatment method in recent years. However, the ultrasound signal utilized for SDT is usually located at a low-frequency spectrum (<2 MHz), and in the field of SDT research, few studies have focused on the exploration and development of ultrasound frequency. Studies have shown that the GHz-level ultrasound can increase cell membrane permeability and have a negligible effect on cell vitality. Herein, we reported the study of a GHz thin film bulk acoustic resonator as an ultrasound source for synergistic treatment with nanoscale calcium peroxide (CaO2). It was discovered that this ultrasound source ultimately achieved an efficient therapeutic outcome on mouse breast cancer cell line 4T1. Such GHz-level ultrasound application in SDT is of high significance to broaden the cognition and application scope of SDT. [ABSTRACT FROM AUTHOR]

Objective To evaluate the effect of spliced X-box binding protein 1 (XBP1s) on hypoxia/ reoxygenation (H/R) injury of mouse renal tubular epithelial cells and unravel underlying mechanism. Methods Mouse renal tubular epithelial cells were divided into adenovirus negative control group (Ad-shNC group), targeted silencing XBP1s adenovirus group (Ad-shXBP1s group), Ad-shNC+H/R group and Ad-shXBP1s+H/R group. The apoptosis level, mitochondrial reactive oxygen activity, mitochondrial membrane potential and mitochondrial calcium ion level were detected in each group. Chromatin immunocoprecipitation followed by sequencing (ChIP-seq) was employed to analyze the binding sites of XBP1s in regulating the inositol 1,4,5-trisphosphate receptor (ITPR) family. The expression levels of XBP1s and ITPR family messenger RNA (mRNA) and protein were determined in each group. Results Compared with the Ad-shNC group, the apoptosis level was higher, mitochondrial reactive oxygen species level was increased, mitochondrial membrane potential was decreased and mitochondrial calcium ion level was elevated in the Ad-shNC+H/R group. Compared with the Ad-shNC+H/R group, the apoptosis level was lower, mitochondrial reactive oxygen species level was decreased, mitochondrial membrane potential was elevated, and mitochondrial calcium ion level was decreased in the Ad-shXBP1s+H/R group (all P<0.05). Compared with the Ad-shNC group, relative expression levels of XBP1s, ITPR1, ITPR2 and ITPR3 mRNAs and proteins were down-regulated in the Ad-shXBP1s group (all P<0.05). Compared with the Ad-shNC group, relative expression levels of XBP1s, ITPR1, ITPR2 and ITPR3 proteins were up-regulated in the Ad-shNC+H/R group. Compared with the Ad-shNC+H/R group, relative expression levels of XBP1s, ITPR1, ITPR2 and ITPR3 were down-regulated in the Ad-shXBP1s+H/R group (all P<0.05). ChIP-seq results showed that XBP1s could bind to the promoter and exon of ITPR1, the exon of ITPR2, and the exon of ITPR3. Conclusions XBP1s may affect mitochondria-associated endoplasmic reticulum membrane structure and function by directly regulating ITPR transcription and translation. Down-regulating XBP1s may inhibit ITPR expression and mitigate mitochondrial damage. [ABSTRACT FROM AUTHOR]

Sonodynamic therapy (SDT) is an emerging cancer treatment method in recent years. However, the ultrasound signal utilized for SDT is usually located at a low-frequency spectrum (<2 MHz), and in the field of SDT research, few studies have focused on the exploration and development of ultrasound frequency. Studies have shown that the GHz-level ultrasound can increase cell membrane permeability and have a negligible effect on cell vitality. Herein, we reported the study of a GHz thin film bulk acoustic resonator as an ultrasound source for synergistic treatment with nanoscale calcium peroxide (CaO2). It was discovered that this ultrasound source ultimately achieved an efficient therapeutic outcome on mouse breast cancer cell line 4T1. Such GHz-level ultrasound application in SDT is of high significance to broaden the cognition and application scope of SDT. [ABSTRACT FROM AUTHOR]

Endocardial endothelium (EE) is a layer of cells covering the cardiac cavities and modulates cardiomyocyte function. This cell type releases several cardioactive factors, including Angiotensin II (Ang II). This octopeptide is known to induce cardiac hypertrophy. However, whether this circulating factor also induces EE hypertrophy is not known. Taurine is known to prevent cardiac hypertrophy. Whether this endogenous antioxidant prevents the effect of Ang II on human EE (hEE) will be verified. Using quantitative fluorescent probe imaging for calcium and reactive oxygen species (ROS), our results show that Ang II induces (10−7 M, 48 h treatment) an increase in hEE cell (hEEC) volume and its nucleus. Pretreatment with 20 mM of taurine prevents morphological remodeling and increases intracellular calcium and ROS. These results suggest that the reported Ang II induces cardiac hypertrophy is associated with hEEC hypertrophy. This later effect is prevented by taurine by reducing intracellular calcium and ROS overloads. Thus, taurine could be an excellent tool for preventing Ang II-induced remodeling of hEECs. [ABSTRACT FROM AUTHOR]

Low selectivity and tumor drug resistance are the main hinderances to conventional radiotherapy and chemotherapy against tumor. Ion interference therapy is an innovative anti-tumor strategy that has been recently reported to induce metabolic disorders and inhibit proliferation of tumor cells by reordering bioactive ions within the tumor cells. Calcium cation (Ca2+) are indispensable for all physiological activities of cells. In particular, calcium overload, characterized by the abnormal intracellular Ca2+ accumulation, causes irreversible cell death. Consequently, calcium overload-based ion interference therapy has the potential to overcome resistance to traditional tumor treatment strategies and holds promise for clinical application. In this review, we 1) Summed up the current strategies employed in this therapy; 2) Described the outcome of tumor cell death resulting from this therapy; 3) Discussed its potential application in synergistic therapy with immunotherapy. [ABSTRACT FROM AUTHOR]

Remote Ischemic Preconditioning (RIPC) can reduce myocardial ischemia-reperfusion injury, but its mechanism is not clear. In order to explore the mechanism of RIPC in myocardial protection, we collected myocardial specimens during cardiac surgery in children with tetralogy of Fallot for sequencing. Our study found RIPC reduces the expression of the calcium channel subunit cacna2d3, thereby impacting the function of calcium channels. As a result, calcium overload during ischemia-reperfusion is reduced, and the activation of calpain 1 is inhibited. This ultimately leads to a decrease in calpain 1 cleavage of Bax, consequently inhibiting increased mitochondrial permeability-mediated apoptosis. Notably, in both murine and human models of myocardial ischemia-reperfusion injury, RIPC inhibiting the expression of the calcium channel subunit cacna2d3 and the activation of calpain 1, improving cardiac function and histological outcomes. Overall, our findings put forth a proposed mechanism that elucidates how RIPC reduces myocardial ischemia-reperfusion injury, ultimately providing a solid theoretical foundation for the widespread clinic application of RIPC. [Display omitted] • Remote ischemic preconditioning reduces myocardial ischemia-reperfusion injury. • RIPC can reduce calcium overload during myocardial ischemia-reperfusion by decreasing the expression of the calcium channel subunit cacna2d3. • Remote ischemic preconditioning decreased the expression of calpain 1 in myocardial ischemia-reperfusion injury. • Calpain 1 cleavage activates Bax in myocardial ischemia-reperfusion injury, ultimately resulting in mitochondrial damage. [ABSTRACT FROM AUTHOR]

Background: Caveolin-1, the scaffolding protein of cholesterol-rich invaginations, plays an important role in store-operated Ca2+ influx and its phosphorylation at Tyr14 (p-caveolin-1) is vital to mobilize protection against myocardial ischemia (MI) injury. SOCE, comprising STIM1, ORAI1 and TRPC1, contributes to intracellular Ca2+ ([Ca2+]i) accumulation in cardiomyocytes. The purified extract of steamed Panax ginseng (EPG) attenuated [Ca2+]i overload against MI injury. Thus, the aim of this study was to investigate the possibility of EPG affecting p-caveolin-1 to further mediate SOCE/[Ca2+]i against MI injury in neonatal rat cardiomyocytes and a rat model. Methods: PP2, an inhibitor of p-caveolin-1, was used. Cell viability, [Ca2+]i concentration were analyzed in cardiomyocytes. In rats, myocardial infarct size, pathological damages, apoptosis and cardiac fibrosis were evaluated, p-caveolin-1 and STIM1 were detected by immunofluorescence, and the levels of caveolin-1, STIM1, ORAI1 and TRPC1 were determined by RT-PCR and Western blot. And, release of LDH, cTnI and BNP was measured. Results: EPG, ginsenosides accounting for 57.96%, suppressed release of LDH, cTnI and BNP, and protected cardiomyocytes by inhibiting Ca2+ influx. And, EPG significantly relieved myocardial infarct size, cardiac apoptosis, fibrosis, and ultrastructure abnormality. Moreover, EPG negatively regulated SOCE via increasing p-caveolin-1 protein, decreasing ORAI1 mRNA and protein levels of ORAI1, TRPC1 and STIM1. More importantly, inhibition of the p-caveolin-1 significantly suppressed all of the above cardioprotection of EPG. Conclusions: Caveolin-1 phosphorylation is involved in the protective effects of EPG against MI injury via increasing p-caveolin-1 to negatively regulate SOCE/[Ca2+]i.

As a transcriptional activator widely expressed in various tissues, nuclear factor of activated T cells (NFAT) is involved in the regulation of the immune system, the development of the heart and brain systems, and classically mediating pathological processes such as cardiac hypertrophy. Oxidative stress is an imbalance of intracellular redox status, characterized by excessive generation of reactive oxygen species, accompanied by mitochondrial dysfunction, calcium overload, and subsequent lipid peroxidation, inflammation, and apoptosis. Oxidative stress occurs during various pathological processes, such as chronic hypoxia, vascular smooth muscle cell phenotype switching, ischemia-reperfusion, and cardiac remodeling. Calcium overload leads to an increase in intracellular calcium concentration, while NFAT can be activated through calcium-calcineurin, which is also the main regulatory mode of NFAT factors. This review focuses on the effects of NFAT transcription factors on reactive oxygen species production, calcium overload, mitochondrial dysfunction, redox reactions, lipid peroxidation, inflammation, and apoptosis in response to oxidative stress. We hope to provide a reference for the functions and characteristics of NFAT involved in various stages of oxidative stress as well as related potential targets. [Display omitted] • Oxidative stress is a leading cause of certain diseases. • Calcium overload is an important part of oxidative stress. • Calcium overload is the main trigger of NFAT activation. • Different downstream target genes of NFAT lead to different effects in oxidative stress. [ABSTRACT FROM AUTHOR]

Background Pulsus alternans has been considered a sign of poor prognosis in patients undergoing treatments for heart failure. However, it may be overlooked in patients with intra-aortic balloon pumps (IABPs). The use of IABP and ivabradine for a β-blocker introduction in a patient with dilated cardiomyopathy (DCM) and pulsus alternans and its consequence have never been reported. Case summary In a 16-year-old high school boy with idiopathic DCM [left ventricular end-diastolic diameter (LVDd), 72 mm; left ventricular ejection fraction (LVEF), 18%], the introduction of carvedilol therapy failed, causing cardiogenic shock under inotropes. Therefore, an IABP support was provided, and he was transferred to our hospital. The arterial pressure waveform under IABP demonstrated pulsus alternans with sinus tachycardia at 135/min. Ivabradine reduced the heart rate to ∼100/min and eliminated the pulsus alternans neither decreasing the cardiac index nor increasing the pulmonary artery wedge pressure. Subsequently, carvedilol was reintroduced, and IABP and inotropes were discontinued. Then, 112 days after his transfer to our hospital, left ventricular reverse remodelling was confirmed (LVDd, 54 mm; LVEF, 44%), and he returned to school. The carvedilol dose reached 20 mg/day in 4 months after discharge, and further improvement was observed a year after discharge (LVDd, 54 mm; LVEF, 52%). Discussion Pulsus alternans is considered a predictor of poor prognosis. However, IABP and ivabradine may stabilize the haemodynamics in pulsus alternans, leading to a successful β-blocker introduction. [ABSTRACT FROM AUTHOR]

Duchenne muscular dystrophy (DMD) is the most common muscular dystrophy and is caused by mutations in the dystrophin gene. Dystrophin deficiency is associated with structural and functional changes of the muscle cell sarcolemma and/or stretchinduced ion channel activation. In this investigation, we use mice with transgenic cardiomyocyte-specific expression of the GCaMP6f Ca2+ indicator to test the hypothesis that dystrophin deficiency leads to cardiomyocyte Ca2+ handling abnormalities following preload challenge. α-MHC-MerCreMer-GCaMP6f transgenic mice were developed on both a wild-type (WT) or dystrophic (Dmdmdx-4Cv) background. Isolated hearts of 3-7-mo male mice were perfused in unloaded Langendorff mode (0 mmHg) and working heart mode (preload = 20 mmHg). Following a 30-min preload challenge, hearts were perfused in unloaded Langendorff mode with 40 µM blebbistatin, and GCaMP6f was imaged using confocal fluorescence microscopy. Incidence of premature ventricular complexes (PVCs) was monitored before and following preload elevation at 20 mmHg. Hearts of both wildtype and dystrophic mice exhibited similar left ventricular contractile function. Following preload challenge, dystrophic hearts exhibited a reduction in GCaMP6f-positive cardiomyocytes and an increase in number of cardiomyocytes exhibiting Ca2+ waves/overload. Incidence of cardiac arrhythmias was low in both wild-type and dystrophic hearts during unloaded Langendorff mode. However, after preload elevation to 20-mmHg hearts of dystrophic mice exhibited an increased incidence of PVCs compared with hearts of wild-type mice. In conclusion, these data indicate susceptibility to preload-induced Ca2+ overload, ventricular damage, and ventricular dysfunction in male Dmdmdx-4Cv hearts. Our data support the hypothesis that cardiomyocyte Ca2+ overload underlies cardiac dysfunction in muscular dystrophy. [ABSTRACT FROM AUTHOR]

Pirarubicin (THP) is a widely used antitumor drug in clinical practice, but its cardiotoxicity limits its use. The aim of this study was to investigate the protective effect and mechanism of knockdown of lncRNA Miat in THP‐induced cardiotoxicity. The extent of damage to immortalized cardiomyocytes in mice was assessed by CCK8, TUNEL, ROS, Ca2+, RT‐qPCR, and Western blot. The relative levels of Miat in THP‐treated cardiomyocytes (HL‐1) were measured. The protective effect of Miat on THP‐treated HL‐1 was assessed. The binding relationship between lncRNA Miat and mmu‐miRNA‐129‐1‐3p was verified by a dual luciferase reporter gene assay. The protective role of Miat/miRNA‐129‐1‐3p in THP‐induced HL‐1 was explored by performing a rescue assay. THP reduced cell viability, induced apoptosis, triggered oxidative stress and calcium overload. Expression of Miat in HL‐1 was significantly elevated after THP treatment. Miat knockdown significantly alleviated the cardiotoxicity of THP. MiR‐129‐1‐3p is a direct target of Miat. Knockdown of miR‐129‐1‐3p reversed the protective effect of Miat knockdown on HL‐1. Miat knockdown can alleviate THP‐induced cardiomyocyte injury by regulating miR‐129‐1‐3p. [ABSTRACT FROM AUTHOR]

Epilepsy is a chronic brain disease and often occurs suddenly for no reason. Eucommiae folium (EF), an edible herb, can be used in the treatment of various kinds of brain diseases in clinic. From the perspective of safety and efficacy, EF is especially suitable for the treatment of chronic brain diseases. With the help of biolabels, this study was aimed to explore the value and feasibility of EF in the treatment of epilepsy. Proteomics and metabolomics were used to explore the biolabels of EF intervention in brain tissues. Bioinformatics was then applied to topologically analyze its neuroprotective effects and mechanisms and material basis based on biolabels, which were validated in an animal model. The biolabel-led research revealed that EF may exert the therapeutic potential to treat brain diseases through the interaction between multiple compounds and multiple targets, among which its therapeutic potential for epilepsy is particularly prominent. In the pentylenetetrazole-induction model, EF and four active compounds (oleamide, catechol, chlorogenic acid, and kaempferol) protected epileptic hippocampal neurons (Nissl and FJB staining) against mitochondrial dysfunction (MYH6, MYL3, and MYBPC3, etc.) and calcium overload (TNNI3, TNNC1, and TNNT2, etc.) through the hypertrophic cardiomyopathy pathway. This study provides new evidence and insights for the neuroprotective effects of EF, in which four active compounds may be potential drug candidates for the treatment of epilepsy. [ABSTRACT FROM AUTHOR]

Aconitine is a crucial toxic component in Chinese herbal medicines such as Aconitum, Aconitum coreanum, and Aconitum soongaricum. The poisoning symptoms of the central nervous system and cardiovascular system caused by it are relatively common in China, and there are many studies on cardiovascular system diseases caused by aconitine. However, the specific mechanism of neurotoxicity induced by aconitine is still unclear. This study explored the effect and mechanism of mitochondrial calcium uniporter on mitochondrial energy metabolism disorder in aconitine poisoning hippocampal neurons. The results showed that after treatment with 400μmol/L aconitine, mitochondrial energy metabolism was abnormal in rat hippocampal neuron cells, the expression of MCU in mitochondria was up-regulated, calcium overload in mitochondria, ATP production decreased, and mitochondrial membrane potential Changes, increased expression of the apoptosis gene Cleaved-Caspase-3. After treatment with the MCU agonist spermine, mitochondrial energy metabolism was significantly abnormal, and cell apoptosis was increased considerably. However, pretreatment with calcium ion channel inhibitor Ruthenium Red (RR) effectively promoted the generation of ATP, thereby improving mitochondrial energy metabolism disorders and reducing cell apoptosis. These results suggest that aconitine induces mitochondrial energy metabolism dysfunction in hippocampal neurons, which may be related to the increased expression of MCU. [Display omitted] • Aconitine affects mitochondrial energy metabolism by inducing mitochondrial calcium overload and inhibiting ATP production. • Aconitine induces mitochondrial energy metabolism disorder by enhancing MCU signaling pathway. • Aconitine increases the apoptosis of HT22 cells by enhancing the MCU signaling pathway. [ABSTRACT FROM AUTHOR]

Endocardial endothelium (EE) is a layer of cells covering the cardiac cavities and modulates cardiomyocyte function. This cell type releases several cardioactive factors, including Angiotensin II (Ang II). This octopeptide is known to induce cardiac hypertrophy. However, whether this circulating factor also induces EE hypertrophy is not known. Taurine is known to prevent cardiac hypertrophy. Whether this endogenous antioxidant prevents the effect of Ang II on human EE (hEE) will be verified. Using quantitative fluorescent probe imaging for calcium and reactive oxygen species (ROS), our results show that Ang II induces (10−7 M, 48 h treatment) an increase in hEE cell (hEEC) volume and its nucleus. Pretreatment with 20 mM of taurine prevents morphological remodeling and increases intracellular calcium and ROS. These results suggest that the reported Ang II induces cardiac hypertrophy is associated with hEEC hypertrophy. This later effect is prevented by taurine by reducing intracellular calcium and ROS overloads. Thus, taurine could be an excellent tool for preventing Ang II-induced remodeling of hEECs.

OBJECTIVE: To probe into the effect of bisoprolol on H9C2 cardiomyocyte injury induced by ischemia reperfusion (I/ R) and its mechanism. METHODS: H9C2 cardiomyocytes were cultured in vitro and divided into the control group ( Control group ), hypoxia / reoxygenation ( H / R) model group ( Model group ), bisoprolol group (Bisoprolol group), bisoprolol + apoptosis signal-regulated kinase 1 (ASK1) recombinant protein group (Bisoprolol+ ASK1 group). Except for the Control group, the H9C2 cardiomyocytes were treated with H / R injury in the rest groups. The cell viability was detected by cell counting kit (CCK8) method; the cell apoptosis was detected by flow cytometry; the myocardial injury markers [ lactate dehydrogenase ( LDH ), cardiac troponin T ( cTnT )] and inflammatory factors [ interleukin 6 ( IL-6), interleukin 1β ( IL-1β) and tumor necrosis factor α (TNF-α)] levels were measured by enzyme-linked immunosorbent assay; the calcium ion concentration in cells was measured by laser confocal assay; the ASK1-c-Jun amino-terminal kinase ( JNK) / p38 mitogen-activated protein kinase ( p38 MAPK) signaling pathway-related protein expression was detected by Western blotting. RESULTS: Compared with the Control group, the H9C2 cell viability, LDH and cTnT levels were lower, the cell apoptosis rate, IL-6, IL-1β and TNF-α levels were higher, the calcium ion concentration, p-ASK1 / ASK1, p-JNK/ JNK and p-p38 MAPK/ p38 MAPK ratio were higher in the Model group, with statistically significant differences (P<0. 05). Compared with the Model group, the H9C2 cell viability, LDH and cTnT levels were higher, the cell apoptosis rate, IL-6, IL-1β and TNF-α levels were lower, the calcium ion concentration, p-ASK1 / ASK1, p-JNK/ JNK and p-p38 MAPK/ p38 MAPK ratio were lower in the Bisoprolol group and Bisoprolol + ASK1 group, with statistically significant differences ( P < 0. 05). Compared with the Bisoprolol group, the H9C2 cell viability, LDH and cTnT levels were lower, the cell apoptosis rate, IL-6, IL-1β and TNF-α levels were higher, the calcium ion concentration, p-ASK1 / ASK1, p-JNK/ JNK and p-p38 MAPK/ p38 MAPK ratio were higher in the Bisoprolol +ASK1 group, with statistically significant differences (P<0. 05). CONCLUSIONS: Bisoprolol can improve H9C2 cardiomyocyte injury induced by I/ R through inhibiting inflammatory response and calcium overload, its mechanism may related to the inhibition of ASK1-JNK/ p38 MAPK signaling pathway activation. [ABSTRACT FROM AUTHOR]

BACKGROUND: Disorders of calcium metabolism mediate the occurrence and development of chronic fluorosis, but the specific molecular mechanism has not been elucidated and there is little systematic discussion on the role of calcium ion (Ca2+) in the pathogenesis of chronic fluorosis. OBJECTIVE: To review the role of Ca2+ in chronic fluorosis, thereby providing new ideas and perspectives for the exploration of the molecular mechanism of chronic fluorosis and the development of targeted drugs. METHODS: “Ca2+, fluorosis, pathogenesis, calcium overload, oxidative stress, endoplasmic reticulum stress, mitochondrial damage, apoptosis” were used as Chinese and English keywords, and the relevant literatures included in PubMed database and CNKI database from January 2000 to January 2022 were retrieved. After removal of obsolete, repetitive and low-credibility documents, 110 documents were finally included. RESULTS AND CONCLUSION: Ca2+ plays an important role in the pathogenesis of chronic fluorosis. The calcium paradox forms of low extracellular calcium caused by bone calcium metabolism disorder and of high intracellular calcium caused by intracellular Ca2+ metabolism disorder jointly induce the damage of fluoride to the bone and non-bone tissues. Intracellular Ca2+ metabolism disorder, with calcium overload as the core link, mediates the occurrence and development of chronic fluorosis. The specific process is as follows: fluorine promotes the production of chronic fluorosis through the inhibition of calcium transporters/enzymes in the plasma membrane and endoplasmic reticulum and the interference of gene expression levels. Cytoplasmic calcium is overloaded, thereby activating the downstream calcium signal transduction pathway, forming a unified negative regulatory network with multiple mechanisms, such as oxidative stress, endoplasmic reticulum stress, mitochondrial damage, and jointly inducing apoptosis in bone and soft tissue cells. In contrast, calcium agents and inhibitors that act on intracellular calcium-related targets (LTCC Cav1.2, NMDARs, and CaM-CAMKII) exert therapeutic effects by reversing fluoride-induced calcium paradoxes. Recovery from Ca2+ metabolism disorders is an important approach for treating chronic fluorosis. From another point of view, this not only provides an immediate theoretical basis for the current clinical application of calcium agents, but also provides new ideas and confidence for the development of drugs acting on calcium-related targets in the future. [ABSTRACT FROM AUTHOR]

AIM: To investigate the therapeutic effect of tetrandrine （Tet） on mouse in vivo and in vitro models of severe acute pancreatitis （SAP） and its mechanisms. METHODS: （1） The pancreatic tissues of C57BL/6 mice were freshly isolated to obtain pancreatic acinar cells （PACs）. The cells were randomly divided into blank control （Ctrl） group, Tet group, injury ［induced by palmitoleic acid （POA） or taurolithocholic acid sodium salt （TLCS）］ groups and Tet treatment （Tet+POA or Tet+TLCS） groups. The Fluo-4 fluorescent probe was used to measure cytoplasmic calcium concentration. Propidium iodide staining was used to detect necrotic cells. The TMRM fluorescent probe was used to measure the changes of mitochondrial membrane potential. Reactive oxygen species （ROS） was detected by DCFH-DA fluorescent probe. （2） Thirty-five 8-week-old healthy male C57BL/6 mice were randomly selected and divided into Ctrl group, sham group, Tet group, fatty acid ethyl ester-induced acute pancreatitis （FAEE-AP） group, TLCS-induced acute pancreatitis （TLCS-AP） group, Tet+FAEE-AP group and Tet+TLCS-AP group, with 5 mice in each group. The morphological changes of the pancreas were observed using HE staining. The positive staining rates of C/EBP homologous protein （CHOP） in the pancreas were observed by immunohistochemistry. The expression of glucose-regulated protein 78 （GRP78）, protein kinase R-like endoplasmic reticulum kinase （PERK）, p-PERK and CHOP was detected by Western blot. Serum levels of amylase, interleukin-6（ IL-6）, malondialdehyde（ MDA）, glutathione peroxidase（ GSH-Px）, superoxide dismutase（ SOD） and catalase （CAT） were assayed. Myeloperoxidase （MPO） activity was detected in mouse pancreatic and lung tissues. RESULTS: Treatment with Tet effectively inhibited POA- or TLCS-induced calcium overload and necrosis in PACs, attenuated the decrease in mitochondrial membrane potential, and reduced ROS production in vitro （P<0. 01）. Compared with Ctrl group, the pancreatic pathological score, serum amylase activity, serum IL-6 level, and MPO activity in the pancreas and lung in vivo significantly increased in SAP groups（ P<0. 01）. However, the administration of Tet significantly alleviated the tissue damage and inflammatory response （P<0. 01）. Compared with SAP groups, Tet reduced the expression of endoplasmic reticulum stress-related GRP78/PERK/CHOP signaling pathway （P<0. 01）, decreased serum peroxide MDA, and increased antioxidants GSH-Px, SOD and CAT （P<0. 01）. CONCLUSION: Treatment with Tet effectively attenuates SAP in mouse models by the inhibition of calcium overload, the alleviation of mitochondrial membrane potential decrease, and the reduction of endoplasmic reticulum stress response and oxidative stress damage to protect against the necrosis of PACs. [ABSTRACT FROM AUTHOR]

Calcium is a highly positively charged ionic species. It regulates all cell types' functions and is an important second messenger that controls and triggers several mechanisms, including membrane stabilization, permeability, contraction, secretion, mitosis, intercellular communications, and in the activation of kinases and gene expression. Therefore, controlling calcium transport and its intracellular homeostasis in physiology leads to the healthy functioning of the biological system. However, abnormal extracellular and intracellular calcium homeostasis leads to cardiovascular, skeletal, immune, secretory diseases, and cancer. Therefore, the pharmacological control of calcium influx directly via calcium channels and exchangers and its outflow via calcium pumps and uptake by the ER/SR are crucial in treating calcium transport remodeling in pathology. Here, we mainly focused on selective calcium transporters and blockers in the cardiovascular system. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S) is the most recently discovered gasotransmitter molecule that activates multiple intracellular signaling pathways and exerts concentration-dependent antitumor effect by interfering with mitochondrial respiration and inhibiting cellular ATP generation. Inspired by the fact that H2S can also serve as a promoter for intracellular Ca2+ influx, tumor-specific nanomodulators (I-CaS@PP) have been constructed by encapsulating calcium sulfide (CaS) and indocyanine green (ICG) into methoxy poly (ethylene glycol)-b-poly (lactide-co-glycolide) (PLGA-PEG). I-CaS@PP can achieve tumor-specific biodegradability with high biocompatibility and pH-responsive H2S release. The released H2S can effectively suppress the catalase (CAT) activity and synergize with released Ca2+ to facilitate abnormal Ca2+ retention in cells, thus leading to mitochondria destruction and amplification of oxidative stress. Mitochondrial dysfunction further contributes to blocking ATP synthesis and downregulating heat shock proteins (HSPs) expression, which is beneficial to overcome the heat endurance of tumor cells and strengthen ICG-induced photothermal performance. Such a H2S-boosted Ca2+-involved tumor-specific therapy exhibits highly effective tumor inhibition effect with almost complete elimination within 14-day treatment, indicating the great prospect of CaS-based nanomodulators as antitumor therapeutics.

Sodium-glucose transporter 2 inhibitors (SGLT2is) exert significant cardiovascular and heart failure benefits in type 2 diabetes mellitus (DM) patients and can help reduce cardiac arrhythmia incidence in clinical practice. However, its effect on regulating cardiomyocyte mitochondria remain unclear. To evaluate its effect on myocardial mitochondria, C57BL/6J mice were divided into four groups, including: (1) control, (2) high fat diet (HFD)-induced metabolic disorder and obesity (MDO), (3) MDO with empagliflozin (EMPA) treatment, and (4) MDO with glibenclamide (GLI) treatment. All mice were sacrificed after 16 weeks of feeding and the epicardial fat secretome was collected. H9c2 cells were treated with the different secretomes for 18 h. ROS production, Ca2+ distribution, and associated proteins expression in mitochondria were investigated to reveal the underlying mechanisms of SGLT2is on cardiomyocytes. We found that lipotoxicity, mitochondrial ROS production, mitochondrial Ca2+ overload, and the levels of the associated protein, SOD1, were significantly lower in the EMPA group than in the MDO group, accompanied with increased ATP production in the EMPA-treated group. The expression of mfn2, SIRT1, and SERCA were also found to be lower after EMPA-secretome treatment. EMPA-induced epicardial fat secretome in mice preserved a better cardiomyocyte mitochondrial biogenesis function than the MDO group. In addition to reducing ROS production in mitochondria, it also ameliorated mitochondrial Ca2+ overload caused by MDO-secretome. These findings provide evidence and potential mechanisms for the benefit of SGLT2i in heart failure and arrhythmias. [ABSTRACT FROM AUTHOR]

Glutamate receptor ionotropic NMDA 2B (GluN2B) plays an essential role in calcium overload during excitotoxicity. Reverse-phase nano-liquid chromatography-tandem mass spectrometry has revealed an interaction between GluN2B and HECT domain E3 ubiquitin protein ligase 4 (HECTD4), an E3 ubiquitin ligase highly expressed in the brain. As a potential substrate for HECTD4, mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) acts as a scaffold with hydrolysis activity. This study explores the relationship between HECTD4, GluN2B, and MALT1, focusing on their role in brain injury in ischemic stroke. Rats were subjected to 2 h-ischemia followed by 24-h reperfusion to establish an ischemic stroke model. We observed the downregulation of HECTD4 and the upregulation of MALT1. Additionally, an increased GluN2B phosphorylation was concomitant with weakened interactions between HECTD4 and GluN2B, followed by decreased striatal-enriched protein phosphatase (STEP61). Knockdown of HECTD4 exacerbated hypoxia- or NMDA-induced injury in nerve cells coincident with a decrease in GluN2B and MALT1 ubiquitination, and an increase in GluN2B phosphorylation as well as an increase in intracellular calcium level, which were counteracted by MALT1 siRNA. Blockage of MALT1 with its inhibitor or siRNA reduced STEP61 degradation, accompanied by a decrease in GluN2B phosphorylation, intracellular calcium concentration, and brain cell injury, which were reversed by overexpression of MALT1. Based on these observations, we conclude that the downregulation of HECTD4 in ischemic stroke rat brain accounts for calcium overload and brain injury due to activating GluN2B directly and indirectly through a mechanism involving the reduced ubiquitination of GluN2B and MALT1, respectively. [ABSTRACT FROM AUTHOR]

Ferroptosis is a recently identified iron-dependent form of nonapoptotic cell death characterized by reactive oxygen species (ROS) generation and lipid peroxidation. Here, we report a novel iron-dependent form of ferroptosis induced by labile iron and investigate the mechanism underlying this process. We find that labile iron-induced ferroptosis is distinct from canonical ferroptosis and is linked to the mitochondrial pathway. Specifically, the mitochondrial calcium uniporter mediates the ferroptosis induced by labile iron. Interestingly, cells undergoing labile iron-induced ferroptosis exhibit cytoplasmic features of oncosis and nuclear features of apoptosis. Furthermore, labile iron-induced ferroptosis involves a unique set of genes. Finally, labile iron-induced ferroptosis was observed in liver subjected to acute iron overload in vivo. Our study reveals a novel form of ferroptosis that may be implicated in diseases caused by acute injury. [ABSTRACT FROM AUTHOR]

A growing body of evidence shows that cigarette smoking impairs cognitive performance. The 'Calcium Hypothesis' theory of neuronopathies reveals a critical role of aberrant calcium signaling in compromised cognitive functions. However, the underlying implications of abnormalities in calcium signaling in the neurotoxicity induced by cigarette smoke (CS) have not yet been identified. CACNA2D1, an important auxiliary subunit involved in the composition of voltage-gated calcium channels (VGCCs), was reported to affect the calcium signaling in neurons by facilitating VGCCs-mediated Ca2+ influx. ΔFOSB, an alternatively-spliced product of the Fosb gene, is an activity-dependent transcription factor induced robustly in the brain in response to environmental stimuli such as CS. Interestingly, our preliminary bioinformatics analysis revealed a significant co-expression between ΔFOSB and CACNA2D1 in brain tissues of patients with neurodegenerative diseases characterized by progressive cognitive decline. Therefore, we hypothesized that the activation of the ΔFOSB-CACNA2D1 axis in response to CS exposure might cause dysregulation of calcium homeostasis in hippocampal neurons via VGCCs-mediated Ca2+ influx, thereby contributing to cognitive deficits. To this end, the present study established a CS-induced mouse model of hippocampus-dependent cognitive impairment, in which the activation of the ΔFOSB-CACNA2D1 axis accompanied by severe calcium overload was observed in the mouse hippocampal tissues. More importantly, ΔFOSB knockdown-/overexpression-mediated inactivation/activation of the ΔFOSB-CACNA2D1 axis interdicted/mimicked CS-induced dysregulation of calcium homeostasis followed by severe cellular damage in HT22 mouse hippocampal neurons. Mechanistically speaking, a further ChIP-qPCR assay confirmed the physical interaction between transcription factor ΔFOSB and the Cacna2d1 gene promoter, suggesting a direct transcriptional regulation of the Cacna2d1 gene by ΔFOSB. Overall, our current work aims to deliver a unique insight into the neurotoxic mechanisms induced by CS to explore potential targets for intervention.

Objective To explore the effects of autonomic nervous regulation on structural remodeling, electrical remodeling and fibrosis in rats with ejection fraction preserved heart failure (HFpEF). Methods A total of 44 SPF grade 12-week-old SD rats were selected, 10 of them were selected as the control group, and the remaining 34 rats were used to establish the HFpEF model. The rat HFpEF model was established by ligation of abdominal aorta-inferior vena cava fistula. Among them, 30 rats were successfully modeled, and 4 rats died. The successfully established rats were divided into 3 groups with 10 rats in each group: the model group, the autonomic nerve regulation group and the autonomic nerve regulation+ acetylcholine M2 receptor antagonist group. The autonomic nerve regulation group received percutaneous auricular marginal vagus nerve stimulation on the basis treatment of the model group. In the autonomic regulation + acetylcholine M2 receptor antagonist group, mesotramine (0.5 mg/kg) was injected into the caudal vein every day on the basis treatment of the autonomic nervous regulation group. Left ventricular posterior wall end-diastolic dimension (LVPWD-D), interventricular ventricular septum end-diastolic dimension (IVS-D) and the peak value of mitral flow velocity in the early diastole/peak value of mitral flow velocity in late diastole (E/A) were measured by echocardiography.The effective refractory period (ERP) and monophasic action potential duration (MAPD) of rat hearts were obtained by cardiac electrophysiological stimulator in each group. The value of NT-proBNP was detected by ELISA. The disordered arrangement of cardiomyocytes and the infiltration of inflammatory cells were observed by HE staining. The degree of myocardial fibrosis was observed by Masson staining. The expression levels of matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase-1 (TIMP-1), sarcoplasmic reticulum Ca2+-ATP enzyme (SERCA2a) and its regulatory protein phosphoprotein (PLB) mRNA and protein were detected by RT-PCR and Western blot assay. Results HE staining showed that the arrangement of cardiomyocytes was disordered, the intercellular space was not obvious enough, accompanied by the infiltration of inflammatory cells in the model group. Masson staining showed that the myocardial fibers were disordered, and a large number of collagen fibers were produced in the model group. The above pathological changes were significantly less in the autonomic nervous regulation group than those in the model group. The above pathological changes were not significantly improved in the autonomic nervous regulation + acetylcholine M2 receptor antagonist group compared with those in the model group. Compared with the control group, the values of NT-proBNP, LVPWD-D, IVS-D, ERP, MAPD, MMP-9 mRNA and protein, PLB mRNA and protein were all increased in the model group, and levels of E/A, TIMP-1 mRNA and protein, SERCA2a mRNA and protein decreased significantly (P＜0.05). Compared with the model group, values of NT-proBNP, LVPWD-D, IVS-D, ERP, MAPD, MMP-9 mRNA and protein, PLB mRNA and protein decreased in the autonomic nerve regulation group, and levels of E/A, TIMP-1 mRNA and protein, SERCA2a mRNA and protein were all increased (P＜0.05). There were no significant differences in the above-mentioned indexes between the autonomic nervous regulation + acetylcholine M2 receptor antagonist group and the model group. Conclusion Autonomic nervous regulation may reduce structural remodeling, electrical remodeling and myocardial fibrosis in HFpEF model rats and improve the prognosis of HFpEF through reducing the level of calcium overload [ABSTRACT FROM AUTHOR]

Mitochondria calcium is a double-edged sword. While low levels of calcium are essential to maintain optimal rates of ATP production, extreme levels of calcium overcoming the mitochondrial calcium retention capacity leads to loss of mitochondrial function. In moderate amounts, however, ATP synthesis rates are inhibited in a calcium-titratable manner. While the consequences of extreme calcium overload are well-known, the effects on mitochondrial function in the moderately loaded range remain enigmatic. These observations are associated with changes in the mitochondria ultrastructure and cristae network. The present mini review/perspective follows up on previous studies using well-established cryo–electron microscopy and poses an explanation for the observable depressed ATP synthesis rates in mitochondria during calcium-overloaded states. The results presented herein suggest that the inhibition of oxidative phosphorylation is not caused by a direct decoupling of energy metabolism via the opening of a calcium-sensitive, proteinaceous pore but rather a separate but related calcium-dependent phenomenon. Such inhibition during calcium-overloaded states points towards mitochondrial ultrastructural modifications, enzyme activity changes, or an interplay between both events. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H 2 S) is the most recently discovered gasotransmitter molecule that activates multiple intracellular signaling pathways and exerts concentration-dependent antitumor effect by interfering with mitochondrial respiration and inhibiting cellular ATP generation. Inspired by the fact that H 2 S can also serve as a promoter for intracellular Ca2+ influx, tumor-specific nanomodulators (I-CaS@PP) have been constructed by encapsulating calcium sulfide (CaS) and indocyanine green (ICG) into methoxy poly (ethylene glycol) -b- poly (lactide -co- glycolide) (PLGA-PEG). I-CaS@PP can achieve tumor-specific biodegradability with high biocompatibility and pH-responsive H 2 S release. The released H 2 S can effectively suppress the catalase (CAT) activity and synergize with released Ca2+ to facilitate abnormal Ca2+ retention in cells, thus leading to mitochondria destruction and amplification of oxidative stress. Mitochondrial dysfunction further contributes to blocking ATP synthesis and downregulating heat shock proteins (HSPs) expression, which is beneficial to overcome the heat endurance of tumor cells and strengthen ICG-induced photothermal performance. Such a H 2 S-boosted Ca2+-involved tumor-specific therapy exhibits highly effective tumor inhibition effect with almost complete elimination within 14-day treatment, indicating the great prospect of CaS-based nanomodulators as antitumor therapeutics. A biodegradable nanomodulator (I-CaS@PP) was constructed by encapsulating CaS and ICG into PLGA-PEG, which helped controllably release H 2 S and Ca2+ in the acidic tumor microenvironment for synergistic cascade cancer therapy. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract Background Many clinical studies have shown a correlation between proton pump inhibitors (PPIs) and osteoporosis or fractures. The purpose of this study was to establish a murine model of chronic oral PPI administration to verify whether PPIs caused bone metabolic impairment and investigate the relevant molecular mechanism underlying the effects of PPIs on MC3T3-E1 murine osteoblasts. Methods A lansoprazole-induced bone loss model was used to investigate the damaging effects of PPIs. In vivo, immunohistochemistry, Hematoxylin–Eosin (HE) staining, micro-CT analysis, and blood biochemical analyses were used to evaluate the effect of lansoprazole on bone injury in mice. In vitro, the effects of lansoprazole and related signaling pathways in MC3T3-E1 cells were investigated by CCK-8 assays, EdU assays, flow cytometry, laser confocal microscopy, patch clamping, reverse transcription-quantitative polymerase chain reaction and Western blotting. Results After 6 months of lansoprazole gavage in ICR mice, the micro-CT results showed that compared with that in the vehicle group, the bone mineral density (BMD) in the high-dose group was significantly decreased (P

Hypoxia and high concentration of glutathione (GSH) in tumor seriously hinder the role of reactive oxygen species (ROS) and oxygen-dependence strategy in tumor treatment. In this work, a self-generating oxygen and self-consuming GSH hyaluronic acid (HA)-coated porphyrin nanoplatform (TAPPP@CaO 2 /Pt(IV)/HA) is established for enhancing photodynamic/ion/chemo targeting synergistic therapy of tumor. During the efforts of ROS production by nanosystems, a GSH consuming strategy is implemented for augmenting ROS-induced oxidative damage for synergetic cancer therapy. CaO 2 in the nanosystems is decomposed into O 2 and H 2 O 2 in an acidic environment, which alleviates hypoxia and enhances the photodynamic therapy (PDT) effect. Calcium overload causes mitochondria dysfunction and induces apoptosis. Pt (IV) reacts with GSH to produce Pt (II) for chemotherapy and reduce the concentration of GSH, protecting ROS from scavenging for augmenting ROS-induced oxidative damage. In vitro and in vivo results demonstrated the self-generating oxygen and self-consuming GSH strategy can enhance ROS-dependent PDT coupled with ion/chemo synergistic therapy. The proposed strategy not only solves the long-term problem that hypoxia limits therapeutic effect of PDT, but also ameliorates the highly reducing environment of tumors. Thus the preparation of TAPPP@CaO 2 /Pt(IV)/HA provided a novel strategy for the effective combined therapy of cancers. [Display omitted] [ABSTRACT FROM AUTHOR]

• Bimetallic nanosensitizer, CFT-NPs, revolutionizes low-frequency microwave ablation by enhancing its efficacy while ensuring unparalleled biosafety. • CFT-NPs harness electromagnetic energy for heat & ferroptosis/calcium overload upon pH rupture, revolutionizing iMWA's therapeutic potential. • This nanosensitizer pioneers antitumor therapy, suppressing tumor growth & metastasis enzymes, revolutionizing iMWA ablation & safety challenges. Microwave ablation (MWA) holds promise as a tumor treatment modality, yet incomplete ablation with low-frequency MWA (iMWA) remains a significant obstacle to survival, while the high-frequency MWA poses safety concerns. To address these challenges, we introduce a novel bimetallic iMWA nanosensitizer, CFT-NPs, constructed via metal-coordination interactions between tannic acid (TA) and iron/calcium dual metal ions (Fe3+/Ca2+). The Fe3+/Ca2+ in CFT-NPs work in harmony to convert electromagnetic energy into heat, thereby bolstering the effectiveness of iMWA while maintaining good biosafety. Furthermore, the pH-triggered rupture of CFT-NPs release TA, Fe3+, and Ca2+. The liberated Fe3+ undergoes reduction by TA, and when combined with Ca2+, they trigger ferroptosis and Ca2+ overload respectively, significantly amplifying the therapeutic effects of iMWA. Utilization iMWA with CFT-NPs results in lipid oxidation, mitochondrial dysfunction, and disruption of redox balance, both in vitro and in vivo. Notably, this nanosensitizer exerts a robust antitumor effect, effectively inhibiting tumor growth and downregulating the expression of matrix metalloproteinases, which is associated with tumor metastasis. Collectively, this innovative study offers a promising approach to overcome the challenges of incomplete ablation and biological safety, enhancing the antitumor efficacy of iMWA.. [ABSTRACT FROM AUTHOR]

Zishenhuoxue decoction (ZSHX), a Chinese herbal medicine, exhibits myocardial and vascular endothelial protective properties. The intricate regulatory mechanisms underlying myocardial ischemic injury and its association with dysfunctional mitochondrial quality surveillance (MQS) remain elusive. To study the protective effect of ZSHX on ischemic myocardial injury in mice using a TMBIM6 gene-modified animal model and mitochondrial quality control-related experiments. Using model animals and myocardial infarction surgery-induced ischemic myocardial injury TMBIM6 gene-modified mouse models, the pharmacological activity of ZSHX in inhibiting ischemic myocardial injury and mitochondrial homeostasis disorder in vivo was tested. Our focal point entailed scrutinizing the impact of ZSHX on ischemic myocardial impairment through the prism of TMBIM6. This endeavor was undertaken utilizing mice characterized by heart-specific TMBIM6 knockout (TMBIM6CKO) and their counterparts, the TMBIM6 transgenic (TMBIM6TG) and VDAC1 transgenic (VDAC1TG) mice. ZSHX demonstrated dose-dependent effectiveness in mitigating ischemic myocardial injury and enhancing mitochondrial integrity. TMBIM6CKO hindered ZSHX's cardio-therapeutic and mitochondrial protective effects, while ZSHX's benefits persisted in TMBIM6TG mice. TMBIM6CKO also blocked ZSHX's regulation of mitochondrial function in HR-treated cardiomyocytes. Hypoxia disrupted the MQS in cardiomyocytes, including calcium overload, excessive fission, mitophagy issues, and disrupted biosynthesis. ZSHX counteracted these effects, thereby normalizing MQS and inhibiting calcium overload and cardiomyocyte necroptosis. Our results also showed that hypoxia-induced TMBIM6 blockade resulted in the over-activation of VDAC1, a major mitochondrial calcium uptake pathway, while ZSHX could increase the expression of TMBIM6 and inhibit VDAC1-mediated calcium overload and MQS abnormalities. Our findings suggest that ZSHX regulates mitochondrial calcium homeostasis and MQS abnormalities through a TMBIM6-VDAC1 interaction mechanism, which helps to treat ischemic myocardial injury and provides myocardial protection. This study also offers insights for the clinical translation and application of mitochondrial-targeted drugs in cardiomyocytess. [Display omitted] [ABSTRACT FROM AUTHOR]

Calcium overload therapy refers to the condition of intracellular Ca2+ overload, which causes mitochondrial damage and leads to the uncontrolled release of apoptotic factors into the cytoplasm through the open mitochondrial permeability pore. Based on this, it is playing an increasingly important role in the field of oncology due to its good efficacy and small side effects. However, the regulation of calcium homeostasis by cancer cells themselves, insufficient calcium ions (Ca2+) in tumor sites and low efficiency of calcium entering tumor have limited its efficacy, resulting in unsatisfactory therapeutic effect. Therefore, a novel CAP/BSA@TCP-ZIF-8 nanoparticle drug carrier system was constructed that can provide Ca2+ from exogenous sources for pH-controlled degradation and drug release at the same time. Both in vivo and in vitro experiments have proved that the nanomaterial can activate TRPV1 channels and provide exogenous Ca2+ to cause Ca2+ overload and apoptosis, thus achieving anti-tumor effects. CAP/BSA@TCP-ZIF-8 was synthesized by biomimetic mineralization, injected into mice through the tail vein, and enriched to the tumor area through EPR effect. Weak acidity in the tumor microenvironment stimulates the cleavage of CAP/BSA@TCP-ZIF-8 nanoparticles to release calcium ions and CAP. CAP activates the TRPV1 channel on the surface of the cell membrane to promote the influx of a large number of calcium ions, resulting in intracellular calcium overload. Abnormally increased calcium concentration in cells causes mitochondrial damage and thus apoptosis. [Display omitted] [ABSTRACT FROM AUTHOR]

Evodiamine (EVO), the main active alkaloid in Evodia rutaecarpa, was shown to exert various pharmacological activities, especially anti-tumor. Currently, it is considered a potential anti-cancer drug due to its excellent anti-tumor activity, which unfortunately has adverse reactions, such as the risk of liver and kidney injury, when Evodia rutaecarpa containing EVO is used clinically. In the present study, we aim to clarify the potential toxic target organs and toxicity mechanism of EVO, an active monomer in Evodia rutaecarpa, and to develop mitigation strategies for its toxicity mechanism. Transcriptome analysis and related experiments showed that the PI3K/Akt pathway induced by calcium overload was an important step in EVO-induced apoptosis of renal cells. Specifically, intracellular calcium ions were increased, and mitochondrial calcium ions were decreased. In addition, EVO-induced calcium overload was associated with TRPV1 receptor activation. In vivo TRPV1 antagonist and calcium chelator effects were observed to significantly reduce body weight loss and renal damage in mice due to EVO toxicity. The potential nephrotoxicity of EVO was further confirmed by an in vivo test. In conclusion, TRPV1-mediated calcium overload-induced apoptosis is one of the mechanisms contributing to the nephrotoxicity of EVO due to its toxicity, whereas maintaining body calcium homeostasis is an effective measure to reduce toxicity. These studies suggest that the clinical use of EVO-containing herbal medicines should pay due attention to the changes in renal function of patients as well as the off-target effects of the drugs. [Display omitted] • Evodiamine, a naturally active small molecule derived from plants, has the potential to be nephrotoxic. • Evodiamine-induced calcium homeostasis imbalance plays a crucial role in the toxicity of normal renal cells (HK-2). • Mechanistically, TRPV1-mediated calcium overload-induced apoptosis was revealed to be one of the mechanisms of evodiamine nephrotoxicity based on in vivo and in vitro studies. • Proposing a detoxification strategy: maintaining calcium homeostasis to alleviate evodiamine-induced renal injury. [ABSTRACT FROM AUTHOR]

Iron is an essential element for various cellular metabolism. Cancer cells also have high requirement of iron in their proliferation, invasion, and metastasis processes. Alendronate (ALN), a kind of FDA‐approved bisphosphonates with metal‐chelating capability, is initially certified to selectively bind to intracellular Fe3+ theoretically and experimentally in this study. Hence, CaALN iron nanochelator is rationally designed to kill cancer cells by synergism of Fe‐depletion and calcium accumulation. In vitro experiments and RNA sequencing analysis indicate that CaALN nanomedicine inhibits the proliferation of cancer cells by depleting Fe, interfering with DNA replication, and triggering intracellular reactive oxygen species (ROS). Meanwhile, released Ca2+ and ROS mutually promote and induce damage of cellular macromolecules, which leads to mitochondrial apoptosis of cancer cells. In an intraperitoneal disseminated mouse model with the human ovarian cancer cells SKOV3, CaALN nanoparticles selectively accumulate in tumor tissues and result in significant retardation of tumor growth and ascites formation. The mean survival time of SKOV3‐bearing mice in treatment group is prolonged from 33 to 90 d. These results indicate that the alendronate‐originated iron chelator can serve as an efficient strategy for the treatment of peritoneal carcinomatosis. [ABSTRACT FROM AUTHOR]

Although surgical resection is currently the first choice of clinical treatment for most solid tumors, postoperative cancer recurrence and metastasis are the main causes of mortality. Herein, the authors aim to enable immunotherapy consistent with surgery. To this end, the term "therapeutic‐prophylactic vaccine (TPV)" is suggested, and a TPV‐gel is developed as a filler after resection of ≈90% tumor to eradicate residue tumor (therapeutic) and prevent recurrence and metastasis (prophylactic). The TPV‐gel is made of the matrix of blends of two poly(d,l‐lactide‐co‐glycolide)‐b‐poly(ethylene glycol)‐b‐poly(d,l‐lactide‐co‐glycolide) block copolymers and the bioactive substances of inorganic calcium salt and organic R837. The aqueous system of polymeric block blends undergoes a sol‐gel transition upon heating and thus leads to an injectable hydrogel filling the resection site; loading of CaCl2 and CaCO3 results in the release of calcium ions out of the TPV‐gel, which induces immunogenic cell death of the residual tumor cells; R837, an immune adjuvant, is dispersed in the TPV‐gel as microcrystal and can be released to awaken immune responses. The therapeutic and prophylactic efficacy of this TPV‐gel is confirmed in vitro and in vivo using a postoperative breast 4T1 mice model. [ABSTRACT FROM AUTHOR]

Background: Hypercalcemia induced by multiple myeloma (MM) affects the biological functions of excitable and non-excitable cells. However, red blood cells (RBCs) regulatory effect on calcium in hypercalcemia is still not fully understood. Methods: A total of 113 patients with MM osteolytic lesions were studied retrospectively. Flow cytometry and atomic absorption spectroscopy were used to detect calcium content. Immunofluorescence and Western blotting were used to investigate protein expression. GEO and miRNA databases were used to screen miRNAs. Exosomal miR-4261 migration was investigated by Transwell assay. Dual-luciferase assays confirmed the targeting relationship between miR-4261 and ATP2B4. An RBC oxidative stress model was constructed, and Omega-Agatoxin IVA was used to study the role of plasma membrane Ca2+-ATPase 4 (PMCA4) in RBCs. Results: The results showed that MM RBCs had calcium overload, and serum calcium levels increased as the number of RBCs decreased. The expression of PMCA4 in MM RBCs was significantly lower than in normal RBCs. The exosomal miR-4261 produced by MM cells could be transferred to RBCs to downregulate the expression of ATP2B4. Conclusions: Studies have confirmed that RBCs experience calcium overload inMMwith osteolytic lesions, which is related to the downregulation of ATP2B4 by MM exosomal miR-4261. [ABSTRACT FROM AUTHOR]

The adverse effects of amorphous silica nanoparticles (SiNPs) exposure on the respiratory system were increasingly recognized, however, its potential pathogenesis still remains not fully elucidated. So, this study aimed to explore its effects on pulmonary injury, and to investigate related mechanisms. Histological investigations illustrated SiNPs triggered the lung injury, mainly manifested as alveolar structure destruction, collagen deposition, and mitochondrial ultrastructural injury. In particular, SiNPs greatly enhanced pulmonary ROS and TUNEL positive rate in lungs, both of which were positively correlated with lung impairments. Further, the underlying mechanisms were investigated in cultured human bronchial epithelial cells (16HBE). Consistent with the in vivo findings, SiNPs caused the impairments on mitochondrial structure, as well as the activation of ROS generation and oxidative injury. Upon SiNPs stimuli, mitochondrial respiration was greatly inhibited, while Ca2+ overload in cytosol and mitochondria owing to ER calcium release was noticed, resulting in mitochondrial-dependent epithelial apoptosis. More importantly, mitochondrial dynamics was imbalanced toward a fission type, as evidenced by upregulated DRP1 and its phosphorylation at Ser616 (DRP1s616), while downregulated DRP1s637, and also MFN1, MFN2. Mechanistic investigations revealed that the activation of ROS/Ca2+ signaling promoted DRP1-mediated mitochondrial fission by SiNPs, forming a vicious cycle, and ultimately contributing to apoptosis in 16HBE. In summary, our results disclosed SiNPs caused pulmonary injury through the induction of epithelial apoptosis via a ROS/Ca2+/DRP1-mediated mitochondrial fission axis. [ABSTRACT FROM AUTHOR]

Cardiac ischemia, hypoxia, arrhythmias, and heart failure share the common electrophysiological changes featured by the elevation of intracellular Ca2+ (Ca2+ overload) and inhibition of the inward rectifier potassium (IK1) channel. IK1 channel agonists have been considered a new type of anti‐arrhythmia and cardioprotective agents. We predicted using a drug repurposing strategy that tetramisole (Tet), a known anthelminthic agent, was a new IK1 channel agonist. The present study aimed to experimentally identify the above prediction and further demonstrate that Tet has cardioprotective effects. Results of the whole‐cell patch clamp technique showed that Tet at 1–100 μmol/L enhanced IK1 current, hyperpolarized resting potential (RP), and shortened action potential duration (APD) in isolated rat cardiomyocytes, while without effects on other ion channels or transporters. In adult Sprague–Dawley (SD) rats in vivo, Tet showed anti‐arrhythmia and anticardiac remodeling effects, respectively, in the coronary ligation‐induced myocardial infarction model and isoproterenol (Iso, i.p., 3 mg/kg/day, 10 days) infusion‐induced cardiac remodeling model. Tet also showed anticardiomyocyte remodeling effect in Iso (1 μmol/L) infused adult rat ventricular myocytes or cultured H9c2 (2‐1) cardiomyocytes. Tet at 0.54 mg/kg in vivo or 30 μmol/L in vitro showed promising protections on acute ischemic arrhythmias, myocardial hypertrophy, and fibrosis. Molecular docking was performed and identified the selective binding of Tet with Kir2.1. The cardioprotection of Tet was associated with the facilitation of IK1 channel forward trafficking, deactivation of PKA signaling, and inhibition of intracellular calcium overload. Enhancing IK1 may play dual roles in anti‐arrhythmia and antiventricular remodeling mediated by restoration of Ca2+ homeostasis. [ABSTRACT FROM AUTHOR]

Myocardial ischemia-reperfusion injury (MIRI) frequently complicates postoperative cardiovascular disease treatment. Necroptosis, a cell death mechanism similar to apoptosis, is regulated by specific signaling pathways and plays an important role in MIRI. Receptor-interacting protein 3 (RIP3), a key protein regulating necroptosis during MIRI, directly phosphorylates calmodulin-dependent protein kinase II (CaMKII). Leading to mitochondrial permeablity transition pore (mPTP) opening and inducing necroptosis. Transient receptor potential canonical channel 6 (TRPC6) regulats Ca 2+ entry, is linked to CaMKII as an important upstream effector. However, the connection between TRPC6 and MIRI necroptosis remains unclear. The study aimed to investigate the relationship between TRPC6 and MIRI necroptosis, with a specific focus on elucidating the role of TRPC6 in regulating CaMKII phosphorylation during cardiac necroptosis via Ca 2+ modulation. METHODS AND RESULTS: The experiment used wild-type (WT) and TRPC6 knockout (TRPC6 -/- ) mice for I/R model construction, and H9c2 myocardial cell line for H/R model. After ischemia-reperfusion (I/R), TRPC6 protein levels in mice significantly increased, exacerbating myocardial injury, infarct size (IS), and cardiac function in WT mice. In contrast, TRPC6 knockout attenuated myocardial injury, IS, and improved cardiac function. The results showed a significant correlation between changes in CaMKII and TRPC6. TRPC6 knockout led to decreased intracellular calcium levels, CaMKII phosphorylation, reactive oxygen species levels, mPTP opening, and improve mitochondrial structure. CONCLUSION: I/R upregulates TRPC6, which mediates Ca 2+ entry and CaMKII phosphorylation, exacerbates oxidative stress, and induces necroptosis. These findings suggest a potential therapeutic avenue for mitigating MIRI by targeting TRPC6., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)