NPS-2143 inhibit glioma progression by suppressing autophagy through mediating AKT-mTOR pathway.

Gliomas are the most common tumours in the central nervous system. In the present study, we aimed to find a promising anti-glioma compound and investigate the underlying molecular mechanism. Glioma cells were subjected to the 50 candidate compounds at a final concentration of 10 µM for 72 h, and CCK-8 was used to evaluate their cytotoxicity. NPS-2143, an antagonist of calcium-sensing receptor (CASR), was selected for further study due to its potent cytotoxicity to glioma cells. Our results showed that NPS-2143 could inhibit the proliferation of glioma cells and induce G1 phase cell cycle arrest. Meanwhile, NPS-2143 could induce glioma cell apoptosis by increasing the caspase-3/6/9 activity. NPS-2143 impaired the immigration and invasion ability of glioma cells by regulating the epithelial-mesenchymal transition process. Mechanically, NPS-2143 could inhibit autophagy by mediating the AKT-mTOR pathway. Bioinformatic analysis showed that the prognosis of glioma patients with low expression of CASR mRNA was better than those with high expression of CASR mRNA. Gene set enrichment analysis showed that CASR was associated with cell adhesion molecules and lysosomes in glioma. The nude mice xenograft model showed NPS-2143 could suppress glioma growth in vivo. In conclusion, NPS-2143 can suppress the glioma progression by inhibiting autophagy.

Carbon doped hexagonal boron nitride as an efficient metal-free catalyst for NO capture and reduction.

The electrochemical NO reduction reaction (NORR) towards NH3 is considered a promising strategy to cope with both NO removal and NH3 production. Currently, the research on NORR electrocatalysts mainly focuses on metal-based catalysts, while metal-free catalysts are quite scarce. In this work, we have systematically investigated the properties of pristine and C/O doped h-BN for efficient NO capture and reduction. Our results reveal that the basal plane of pristine h-BN is inert to the adsorption of NO, while doping C or O can significantly enhance the NO capture abilities of h-BN. Then, we highlight that C-doped h-BN exhibits excellent NORR catalytic performance with a relatively low limiting potential of -0.28 V. Further analysis shows that the suitable adsorption strength of NO on the C-doped h-BN surface is the prime reason for its excellent NO reduction activity, which is shown to be due to appropriate electronic interactions between the active site and NO. Last but not least, the catalytic selectivity of h-BN towards the NORR is confirmed by inhibiting the competing hydrogen evolution reaction. Our findings not only provide deeper insight into the essential effect of element doping on the catalytic activities of h-BN, but also propose general design principles for high-performance metal-free NORR electrocatalysts.

Obesity and atrial fibrillation: a narrative review from arrhythmogenic mechanisms to clinical significance.

The prevalence of obesity and atrial fibrillation (AF), which are inextricably linked, is rapidly increasing worldwide. Obesity rates are higher among patients with AF than healthy individuals. Some epidemiological data indicated that obese patients were more likely to develop AF, but others reported no significant correlation. Obesity-related hypertension, diabetes, and obstructive sleep apnea are all associated with AF. Additionally, increased epicardial fat, systemic inflammation, and oxidative stress caused by obesity can induce atrial enlargement, inflammatory activation, local myocardial fibrosis, and electrical conduction abnormalities, all of which led to AF and promoted its persistence. Weight loss reduced the risk and reversed natural progression of AF, which may be due to its anti-fibrosis and inflammation effect. However, fluctuations in weight offset the benefits of weight loss. Therefore, the importance of steady weight loss urges clinicians to incorporate weight management interventions in the treatment of patients with AF. In this review, we discuss the epidemiology of obesity and AF, summarize the mechanisms by which obesity triggers AF, and explain how weight loss improves the prognosis of AF.

Homology-directed repair of an MYBPC3 gene mutation in a rat model of hypertrophic cardiomyopathy.

Variants in myosin-binding protein C3 (MYBPC3) gene are a main cause of hypertrophic cardiomyopathy (HCM), accounting for 30% to 40% of the total number of HCM mutations. Gene editing represents a potential permanent cure for HCM. The aim of this study was to investigate whether genome editing of MYBPC3 using the CRISPR/Cas9 system in vivo could rescue the phenotype of rats with HCM. We generated a rat model of HCM ("1098hom") that carried an Mybpc3 premature termination codon mutation (p.W1098x) discovered in a human HCM pedigree. On postnatal day 3, the CRISPR/Cas9 system was introduced into rat pups by a single dose of AAV9 particles to correct the variant using homology-directed repair (HDR). Analysis was performed 6 months after AAV9 injection. The 1098hom rats didn't express MYBPC3 protein and developed an HCM phenotype with increased ventricular wall thickness and diminished cardiac function. Importantly, CRISPR HDR genome editing corrected 3.56% of total mutations, restored MYBPC3 protein expression by 2.12%, and normalized the HCM phenotype of 1098hom rats. Our work demonstrates that the HDR strategy is a promising approach for treating HCM associated with MYBPC3 mutation, and that CRISPR technology has great potential for treating hereditary heart diseases.

Mechanism of histone deacetylases in cardiac hypertrophy and its therapeutic inhibitors.

Cardiac hypertrophy is a key process in cardiac remodeling development, leading to ventricle enlargement and heart failure. Recently, studies show the complicated relation between cardiac hypertrophy and epigenetic modification. Post-translational modification of histone is an essential part of epigenetic modification, which is relevant to multiple cardiac diseases, especially in cardiac hypertrophy. There is a group of enzymes related in the balance of histone acetylation/deacetylation, which is defined as histone acetyltransferase (HAT) and histone deacetylase (HDAC). In this review, we introduce an important enzyme family HDAC, a key regulator in histone deacetylation. In cardiac hypertrophy HDAC I downregulates the anti-hypertrophy gene expression, including Kruppel-like factor 4 (Klf4) and inositol-5 phosphatase f (Inpp5f), and promote the development of cardiac hypertrophy. On the contrary, HDAC II binds to myocyte-specific enhancer factor 2 (MEF2), inhibit the assemble ability to HAT and protect against cardiac hypertrophy. Under adverse stimuli such as pressure overload and calcineurin stimulation, the HDAC II transfer to cytoplasm, and MEF2 can bind to nuclear factor of activated T cells (NFAT) or GATA binding protein 4 (GATA4), mediating inappropriate gene expression. HDAC III, also known as SIRTs, can interact not only to transcription factors, but also exist interaction mechanisms to other HDACs, such as HDAC IIa. We also present the latest progress of HDAC inhibitors (HDACi), as a potential treatment target in cardiac hypertrophy.

Genetic inhibition of nuclear factor of activated T-cell c2 prevents atrial fibrillation in CREM transgenic mice.

AIMS: Abnormal intracellular calcium (Ca2+) handling contributes to the progressive nature of atrial fibrillation (AF), the most common sustained cardiac arrhythmia. Evidence in mouse models suggests that activation of the nuclear factor of activated T-cell (NFAT) signalling pathway contributes to atrial remodelling. Our aim was to determine the role of NFATc2 in AF in humans and mouse models. METHODS AND RESULTS: Expression levels of NFATc1-c4 isoforms were assessed by quantitative reverse transcription-polymerase chain reaction in right atrial appendages from patients with chronic AF (cAF). NFATc1 and NFATc2 mRNA levels were elevated in cAF patients compared with those in normal sinus rhythm (NSR). Western blotting revealed increased cytosolic and nuclear levels of NFATc2 in AF patients. Similar findings were obtained in CREM-IbΔC-X transgenic (CREM) mice, a model of progressive AF. Telemetry ECG recordings revealed age-dependent spontaneous AF in CREM mice, which was prevented by NFATc2 knockout in CREM:NFATc2-/- mice. Programmed electrical stimulation revealed that CREM:NFATc2-/- mice lacked an AF substrate. Morphometric analysis and histology revealed increased atrial weight and atrial fibrosis in CREM mice compared with wild-type controls, which was reversed in CREM:NFATc2-/- mice. Confocal microscopy showed an increased Ca2+ spark frequency despite a reduced sarcoplasmic reticulum (SR) Ca2+ load in CREM mice compared with controls, whereas these abnormalities were normalized in CREM:NFATc2-/- mice. Western blotting revealed that genetic inhibition of Ca2+/calmodulin-dependent protein kinase II-mediated phosphorylation of S2814 on ryanodine receptor type 2 (RyR2) in CREM:RyR2-S2814A mice suppressed NFATc2 activation observed in CREM mice, suggesting that NFATc2 is activated by excessive SR Ca2+ leak via RyR2. Finally, chromatin immunoprecipitation sequencing from AF patients identified Ras and EF-hand domain-containing protein (Rasef) as a direct target of NFATc2-mediated transcription. CONCLUSION: Our findings reveal activation of the NFAT signalling pathway in patients of Chinese and European descent. NFATc2 knockout prevents the progression of AF in the CREM mouse model.

The role of CD36 in cardiovascular disease.

CD36, also known as the scavenger receptor B2, is a multifunctional receptor widely expressed in various organs. CD36 plays a crucial role in the uptake of long-chain fatty acids, the main metabolic substrate in myocardial tissue. The maturation and transportation of CD36 is regulated by post-translational modifications, including phosphorylation, ubiquitination, glycosylation, and palmitoylation. CD36 is decreased in pathological cardiac hypertrophy caused by ischaemia-reperfusion and pressure overload, and increased in diabetic cardiomyopathy and atherosclerosis. Deficiency of CD36 alleviates diabetic cardiomyopathy and atherosclerosis, while overexpression of CD36 eliminates ischaemia-reperfusion damage, together suggesting that CD36 is closely associated with the progression of cardiovascular diseases and may be a new therapeutic target. This review summarizes the regulation and post-translational modifications of CD36 and evaluates its role in cardiovascular diseases and its potential as a therapeutic target.

Trimetazidine Attenuates Heart Failure by Improving Myocardial Metabolism via AMPK.

Energic deficiency of cardiomyocytes is a dominant cause of heart failure. An antianginal agent, trimetazidine improves the myocardial energetic supply. We presumed that trimetazidine protects the cardiomyocytes from the pressure overload-induced heart failure through improving the myocardial metabolism. C57BL/6 mice were subjected to transverse aortic constriction (TAC). After 4 weeks of TAC, heart failure was observed in mice manifested by an increased left ventricular (LV) chamber dimension, an impaired LV ejection fraction evaluated by echocardiography analysis, which were significantly restrained by the treatment of trimetazidine. Trimetazidine restored the mitochondrial morphology and function tested by cardiac transmission electron microscope and mitochondrial dynamic proteins analysis. Positron emission tomography showed that trimetazidine significantly elevated the glucose uptake in TAC mouse heart. Trimetazidine restrained the impairments of the insulin signaling in TAC mice and promoted the translocation of glucose transporter type IV (GLUT4) from the storage vesicle to membrane. However, these cardioprotective effects of trimetazidine in TAC mice were notably abolished by compound C (C.C), a specific AMPK inhibitor. The enlargement of neonatal rat cardiomyocyte induced by mechanical stretch, together with the increased expression of hypertrophy-associated proteins, mitochondria deformation and dysfunction were significantly ameliorated by trimetazidine. Trimetazidine enhanced the isolated cardiomyocyte glucose uptake in vitro. These benefits brought by trimetazidine were also removed with the presence of C.C. In conclusion, trimetazidine attenuated pressure overload-induced heart failure through improving myocardial mitochondrial function and glucose uptake via AMPK.

Epigenetic Mechanism and Therapeutic Implications of Atrial Fibrillation.

Atrial fibrillation (AF) is the most common arrhythmia attacking 1. 5-2.0% of general population worldwide. It has a significant impact on morbidity and mortality globally and its prevalence increases exponentially with age. Therapies like catheter ablation or conventional antiarrhythmic drugs have not provided effective solution to the recurrence for AF over the past decades. Over 100 genetic loci have been discovered to be associated with AF by Genome-wide association studies (GWAS) but none has led to a therapy. Recently potential involvement of epigenetics (DNA methylation, histone modification, and non-coding RNAs) in the initiation and maintenance of AF has partly emerged as proof-of-concept in the mechanism and management of AF. Here we reviewed the epigenetic features involved in AF pathophysiology and provided an update of their implications in AF therapy.

MYH7B variants cause hypertrophic cardiomyopathy by activating the CaMK-signaling pathway.

Hypertrophic cardiomyopathy (HCM) is a common genetic disease, predominantly caused by mutations in cardiac sarcomere genes; however, whether MYH7B causes HCM is not known. In this study, 549 unrelated patients with HCM and 500 healthy-controls were screened using targeted sequencing and whole exome sequencing together. We observed seven variants in MYH7B causing HCM in 8/549 patients, which accounted for 1.46% of HCM cases. Of these seven variants, three likely pathogenic variants in MYH7B co-segregating with 5 HCM patients were identified in three HCM pedigrees without other HCM-associated variants. Myh7b knockout rats were generated and cardiac functions were detected by Millar pressure-volume catheterization and echocardiography. Spontaneous HCM phenotypes, cellular disarray and cardiac fibrosis were observed in both Myh7b+/-/Myh7b-/- rats. Transcriptome sequencing showed that calcium is the key mediator of cardiac hypertrophy in Myh7b knockout. Subsequent analysis confirmed over-activation of CaMK-signaling pathway in cardiomyocytes of Myh7b-/- rats. Furthermore, MYH7B expression in human and rat hearts was identified and microRNA-208a and microRNA-499 levels are unchanged in HCM patients and Myh7b+/-/Myh7b-/- rats. This study is the first to identifyMYH7B variants as cause of HCM, which account for 1.46% of pathogenesisin HCM patients. Activation of CaMK-signaling pathway may be involved in its pathophysiology.

Ranolazine prevents pressure overload-induced cardiac hypertrophy and heart failure by restoring aberrant Na+ and Ca2+ handling.

BACKGROUND: Cardiac hypertrophy and heart failure are characterized by increased late sodium current and abnormal Ca2+ handling. Ranolazine, a selective inhibitor of the late sodium current, can reduce sodium accumulation and Ca 2+ overload. In this study, we investigated the effects of ranolazine on pressure overload-induced cardiac hypertrophy and heart failure in mice. METHODS AND RESULTS: Inhibition of late sodium current with the selective inhibitor ranolazine suppressed cardiac hypertrophy and fibrosis and improved heart function assessed by echocardiography, hemodynamics, and histological analysis in mice exposed to chronic pressure overload induced by transverse aortic constriction (TAC). Ca2+ imaging of ventricular myocytes from TAC mice revealed both abnormal SR Ca 2+ release and increased SR Ca 2+ leak. Ranolazine restored aberrant SR Ca 2+ handling induced by pressure overload. Ranolazine also suppressed Na + overload induced in the failing heart, and restored Na + -induced Ca 2+ overload in an sodium-calcium exchanger (NCX)-dependent manner. Ranolazine suppressed the Ca 2+ -dependent calmodulin (CaM)/CaMKII/myocyte enhancer factor-2 (MEF2) and CaM/CaMKII/calcineurin/nuclear factor of activated T-cells (NFAT) hypertrophy signaling pathways triggered by pressure overload. Pressure overload also prolonged endoplasmic reticulum (ER) stress leading to ER-initiated apoptosis, while inhibition of late sodium current or NCX relieved ER stress and ER-initiated cardiomyocyte apoptosis. CONCLUSIONS: Our study demonstrates that inhibition of late sodium current with ranolazine improves pressure overload-induced cardiac hypertrophy and systolic and diastolic function by restoring Na+ and Ca 2+ handling, inhibiting the downstream hypertrophic pathways and ER stress. Inhibition of late sodium current may provide a new treatment strategy for cardiac hypertrophy and heart failure.

AMPKα2 Protects Against the Development of Heart Failure by Enhancing Mitophagy via PINK1 Phosphorylation.

RATIONALE: Mitochondrial dysfunction plays an important role in heart failure (HF). However, the molecular mechanisms regulating mitochondrial functions via selective mitochondrial autophagy (mitophagy) are poorly understood. OBJECTIVE: We sought to determine the role of AMPK (AMP-activated protein kinase) in selective mitophagy during HF. METHODS AND RESULTS: An isoform shift from AMPKα2 to AMPKα1 was observed in failing heart samples from HF patients and transverse aortic constriction-induced mice, accompanied by decreased mitophagy and mitochondrial function. The recombinant adeno-associated virus Serotype 9-mediated overexpression of AMPKα2 in mouse hearts prevented the development of transverse aortic constriction-induced chronic HF by increasing mitophagy and improving mitochondrial function. In contrast, AMPKα2-/- mutant mice exhibited an exacerbation of the early progression of transverse aortic constriction-induced HF via decreases in cardiac mitophagy. In isolated adult mouse cardiomyocytes, AMPKα2 overexpression mechanistically rescued the impairment of mitophagy after phenylephrine stimulation for 24 hours. Genetic knockdown of AMPKα2, but not AMPKα1, by short interfering RNA suppressed the early phase (6 hours) of phenylephrine-induced compensatory increases in mitophagy. Furthermore, AMPKα2 specifically interacted with phosphorylated PINK1 (PTEN-induced putative kinase 1) at Ser495 after phenylephrine stimulation. Subsequently, phosphorylated PINK1 recruited the E3 ubiquitin ligase, Parkin, to depolarized mitochondria, and then enhanced the role of the PINK1-Parkin-SQSTM1 (sequestosome-1) pathway involved in cardiac mitophagy. This increase in cardiac mitophagy was accompanied by the elimination of damaged mitochondria, improvement in mitochondrial function, decrease in reactive oxygen species production, and apoptosis of cardiomyocytes. Finally, Ala mutation of PINK1 at Ser495 partially suppressed AMPKα2 overexpression-induced mitophagy and improvement of mitochondrial function in phenylephrine-stimulated cardiomyocytes, whereas Asp (phosphorylation mimic) mutation promoted mitophagy after phenylephrine stimulation. CONCLUSIONS: In failing hearts, the dominant AMPKα isoform switched from AMPKα2 to AMPKα1, which accelerated HF. The results show that phosphorylation of Ser495 in PINK1 by AMPKα2 was essential for efficient mitophagy to prevent the progression of HF.

Soluble Epoxide Hydrolase Inhibition Protected against Angiotensin II-induced Adventitial Remodeling.

Epoxyeicosatrienoic acids (EETs), the metabolites of cytochrome P450 epoxygenases derived from arachidonic acid, exert important biological activities in maintaining cardiovascular homeostasis. Soluble epoxide hydrolase (sEH) hydrolyzes EETs to less biologically active dihydroxyeicosatrienoic acids. However, the effects of sEH inhibition on adventitial remodeling remain inconclusive. In this study, the adventitial remodeling model was established by continuous Ang II infusion for 2 weeks in C57BL/6 J mice, before which sEH inhibitor 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU) was administered by gavage. Adventitial remodeling was evaluated by histological analysis, western blot, immunofluorescent staining, calcium imaging, CCK-8 and transwell assay. Results showed that Ang II infusion significantly induced vessel wall thickening, collagen deposition, and overexpression of α-SMA and PCNA in aortic adventitia, respectively. Interestingly, these injuries were attenuated by TPPU administration. Additionally, TPPU pretreatment overtly prevented Ang II-induced primary adventitial fibroblasts activation, characterized by differentiation, proliferation, migration, and collagen synthesis via Ca2+-calcineurin/NFATc3 signaling pathway in vitro. In summary, our results suggest that inhibition of sEH could be considered as a novel therapeutic strategy to treat adventitial remodeling related disorders.

P2y12 Receptor Promotes Pressure Overload-Induced Cardiac Remodeling via Platelet-Driven Inflammation in Mice.

Inflammation plays a critical role in adverse cardiac remodeling and heart failure. The P2y12 receptor is one of the predominant activating receptors for platelets, thus initiating inflammatory responses under various diseases. In this study, we investigated the functional significance of P2y12-mediated platelet activation in pressure overload-induced cardiac remodeling. Notably, P2y12 knockout (P2y12-/-) mice exhibited suppressed transverse aortic constriction-induced changes in cardiac hypertrophy, collagen synthesis, inflammatory cell recruitment, and cardiac dysfunction. Activated platelets and platelet-leukocyte aggregates were markedly downregulated in P2y12 knockout mice compared with wild-type counterparts after transverse aortic constriction. Moreover, bone marrow chimera experiments revealed that wild-type recipients of P2y12 knockout bone marrow markedly improved cardiac function and attenuated cardiac remodeling, reversed by wild-type platelets reinjection. Platelet depletion and P-selectin inhibition mimicked these protective effects by limiting the interaction between activated platelets and leukocytes. Furthermore, activated wild-type platelets directly induced cardiomyocyte hypertrophy and collagen synthesis via α-granule exocytosis, vanished in P2y12 knockout platelets or those administered anti-NSF (N-ethlymalimide-sensitive factor) antibodies. The results suggest that P2y12-mediated platelet activation promotes cardiac remodeling by triggering a series of inflammatory changes and interacting with leukocytes and endotheliocytes.