USP28 Serves as a Key Suppressor of Mitochondrial Morphofunctional Defects and Cardiac Dysfunction in the Diabetic Heart.

BACKGROUND: The majority of people with diabetes are susceptible to cardiac dysfunction and heart failure, and conventional drug therapy cannot correct diabetic cardiomyopathy progression. Herein, we assessed the potential role and therapeutic value of USP28 (ubiquitin-specific protease 28) on the metabolic vulnerability of diabetic cardiomyopathy. METHODS: The type 2 diabetes mouse model was established using db/db leptin receptor-deficient mice and high-fat diet/streptozotocin-induced mice. Cardiac-specific knockout of USP28 in the db/db background mice was generated by crossbreeding db/m and Myh6-Cre+/USP28fl/fl mice. Recombinant adeno-associated virus serotype 9 carrying USP28 under cardiac troponin T promoter was injected into db/db mice. High glucose plus palmitic acid-incubated neonatal rat ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes were used to imitate diabetic cardiomyopathy in vitro. The molecular mechanism was explored through RNA sequencing, immunoprecipitation and mass spectrometry analysis, protein pull-down, chromatin immunoprecipitation sequencing, and chromatin immunoprecipitation assay. RESULTS: Microarray profiling of the UPS (ubiquitin-proteasome system) on the basis of db/db mouse hearts and diabetic patients' hearts demonstrated that the diabetic ventricle presented a significant reduction in USP28 expression. Diabetic Myh6-Cre+/USP28fl/fl mice exhibited more severe progressive cardiac dysfunction, lipid accumulation, and mitochondrial disarrangement, compared with their controls. On the other hand, USP28 overexpression improved systolic and diastolic dysfunction and ameliorated cardiac hypertrophy and fibrosis in the diabetic heart. Adeno-associated virus serotype 9-USP28 diabetic mice also exhibited less lipid storage, reduced reactive oxygen species formation, and mitochondrial impairment in heart tissues than adeno-associated virus serotype 9-null diabetic mice. As a result, USP28 overexpression attenuated cardiac remodeling and dysfunction, lipid accumulation, and mitochondrial impairment in high-fat diet/streptozotocin-induced type 2 diabetes mice. These results were also confirmed in neonatal rat ventricular myocytes and human induced pluripotent stem cell-derived cardiomyocytes. RNA sequencing, immunoprecipitation and mass spectrometry analysis, chromatin immunoprecipitation assays, chromatin immunoprecipitation sequencing, and protein pull-down assay mechanistically revealed that USP28 directly interacted with PPARα (peroxisome proliferator-activated receptor α), deubiquitinating and stabilizing PPARα (Lys152) to promote Mfn2 (mitofusin 2) transcription, thereby impeding mitochondrial morphofunctional defects. However, such cardioprotective benefits of USP28 were largely abrogated in db/db mice with PPARα deletion and conditional loss-of-function of Mfn2. CONCLUSIONS: Our findings provide a USP28-modulated mitochondria homeostasis mechanism that involves the PPARα-Mfn2 axis in diabetic hearts, suggesting that USP28 activation or adeno-associated virus therapy targeting USP28 represents a potential therapeutic strategy for diabetic cardiomyopathy.

HINT2 protects against pressure overload-induced cardiac remodelling through mitochondrial pathways.

Histidine triad nucleotide-binding protein 2 (HINT2) is an enzyme found in mitochondria that functions as a nucleotide hydrolase and transferase. Prior studies have demonstrated that HINT2 plays a crucial role in ischemic heart disease, but its importance in cardiac remodelling remains unknown. Therefore, the current study intends to determine the role of HINT2 in cardiac remodelling. HINT2 expression levels were found to be lower in failing hearts and hypertrophy cardiomyocytes. The mice that overexpressed HINT2 exhibited reduced myocyte hypertrophy and cardiac dysfunction in response to stress. In contrast, the deficiency of HINT2 in the heart of mice resulted in a worsening hypertrophic phenotype. Further analysis indicated that upregulated genes were predominantly associated with the oxidative phosphorylation and mitochondrial complex I pathways in HINT2-overexpressed mice after aortic banding (AB) treatment. This suggests that HINT2 increases the expression of NADH dehydrogenase (ubiquinone) flavoprotein (NDUF) genes. In cellular studies, rotenone was used to disrupt mitochondrial complex I, and the protective effect of HINT2 overexpression was nullified. Lastly, we predicted that thyroid hormone receptor beta might regulate HINT2 transcriptional activity. To conclusion, the current study showcased that HINT2 alleviates pressure overload-induced cardiac remodelling by influencing the activity and assembly of mitochondrial complex I. Thus, targeting HINT2 could be a novel therapeutic strategy for reducing cardiac remodelling.

Macrod1 suppresses diabetic cardiomyopathy via regulating PARP1-NAD+-SIRT3 pathway.

Diabetic cardiomyopathy (DCM), one of the most serious long-term consequences of diabetes, is closely associated with oxidative stress, inflammation and apoptosis in the heart. MACRO domain containing 1 (Macrod1) is an ADP-ribosylhydrolase 1 that is highly enriched in mitochondria, participating in the pathogenesis of cardiovascular diseases. In this study, we investigated the role of Macrod1 in DCM. A mice model was established by feeding a high-fat diet (HFD) and intraperitoneal injection of streptozotocin (STZ). We showed that Macrod1 expression levels were significantly downregulated in cardiac tissue of DCM mice. Reduced expression of Macrod1 was also observed in neonatal rat cardiomyocytes (NRCMs) treated with palmitic acid (PA, 400 µM) in vitro. Knockout of Macrod1 in DCM mice not only worsened glycemic control, but also aggravated cardiac remodeling, mitochondrial dysfunction, NAD+ consumption and oxidative stress, whereas cardiac-specific overexpression of Macrod1 partially reversed these pathological processes. In PA-treated NRCMs, overexpression of Macrod1 significantly inhibited PARP1 expression and restored NAD+ levels, activating SIRT3 to resist oxidative stress. Supplementation with the NAD+ precursor Niacin (50 µM) alleviated oxidative stress in PA-stimulated cardiomyocytes. We revealed that Macrod1 reduced NAD+ consumption by inhibiting PARP1 expression, thereby activating SIRT3 and anti-oxidative stress signaling. This study identifies Macrod1 as a novel target for DCM treatment. Targeting the PARP1-NAD+-SIRT3 axis may open a novel avenue to development of new intervention strategies in DCM. Schematic illustration of macrod1 ameliorating diabetic cardiomyopathy oxidative stress via PARP1-NAD+-SIRT3 axis.

OSMR deficiency aggravates pressure overload-induced cardiac hypertrophy by modulating macrophages and OSM/LIFR/STAT3 signalling.

BACKGROUND: Oncostatin M (OSM) is a secreted cytokine of the interleukin (IL)-6 family that induces biological effects by activating functional receptor complexes of the common signal transducing component glycoprotein 130 (gp130) and OSM receptor ß (OSMR) or leukaemia inhibitory factor receptor (LIFR), which are mainly involved in chronic inflammatory and cardiovascular diseases. The effect and underlying mechanism of OSM/OSMR/LIFR on the development of cardiac hypertrophy remains unclear. METHODS AND RESULTS: OSMR-knockout (OSMR-KO) mice were subjected to aortic banding (AB) surgery to establish a model of pressure overload-induced cardiac hypertrophy. Echocardiographic, histological, biochemical and immunological analyses of the myocardium and the adoptive transfer of bone marrow-derived macrophages (BMDMs) were conducted for in vivo studies. BMDMs were isolated and stimulated with lipopolysaccharide (LPS) for the in vitro study. OSMR deficiency aggravated cardiac hypertrophy, fibrotic remodelling and cardiac dysfunction after AB surgery in mice. Mechanistically, the loss of OSMR activated OSM/LIFR/STAT3 signalling and promoted a proresolving macrophage phenotype that exacerbated inflammation and impaired cardiac repair during remodelling. In addition, adoptive transfer of OSMR-KO BMDMs to WT mice after AB surgery resulted in a consistent hypertrophic phenotype. Moreover, knockdown of LIFR in myocardial tissue with Ad-shLIFR ameliorated the effects of OSMR deletion on the phenotype and STAT3 activation. CONCLUSIONS: OSMR deficiency aggravated pressure overload-induced cardiac hypertrophy by modulating macrophages and OSM/LIFR/STAT3 signalling, which provided evidence that OSMR might be an attractive target for treating pathological cardiac hypertrophy and heart failure.

Salidroside ameliorates pathological cardiac hypertrophy via TLR4-TAK1-dependent signaling.

Salidroside, a prominent active ingredient in traditional Chinese medicines, is garnering increased attention because of its unique pharmacological effects against ischemic heart disease via MAPK signaling, which plays a critical role in regulating the evolution of ventricular hypertrophy. However, the function of Salidroside on myocardial hypertrophy has not yet been elucidated. C57BL/6 mice were subjected to transverse aortic constriction (TAC), and treated with Salidroside (100 mg kg-1  day-1 ) by oral gavage for 3 weeks starting 1 week after surgery. Four weeks after TAC surgery, the mice were subjected to echocardiography and then sacrificed to harvest the hearts for analysis. For in vitro study, neonatal rat cardiomyocytes were used to validate the protective effects of Salidroside in response to Angiotensin II (Ang II, 1 µM) stimulation. Here, we proved that Salidroside dramatically inhibited hypertrophic reactions generated by pressure overload and isoproterenol (ISO) injection. Salidroside prevented the activation of the TAK1-JNK/p38 axis. Salidroside pretreatment of TAK1-inhibited cardiomyocytes shows no additional attenuation of Ang II-induced cardiomyocytes hypertrophy and signaling pathway activation. The overexpression of constitutively active TAK1 removed the protective effects of Salidroside on myocardial hypertrophy. TAC-induced increase of TLR4 protein expression was reduced considerably in the Salidroside treated mice. Transient transfection of small interfering RNA targeting TLR4 (siTLR4) in cardiomyocytes did not further decrease the activation of the TAK1/JNK-p38 axis. In conclusion, Salidroside functioned as a TLR4 inhibitor and displayed anti-hypertrophic action via the TAK1/JNK-p38 pathway.

Contribution of CYP19A1, CYP1A1, and CYP1A2 polymorphisms in coronary heart disease risk among the Chinese Han population.

The previous study has pointed to that endogenous CYP metabolites play an important role in the pathogenesis of coronary heart disease (CHD). The study aimed to identify the association of CYP19A1, CYP1A1, and CYP1A2 polymorphisms with CHD susceptibility in a Chinese Han population. A total of 960 genetically unrelated participants consist of 480 CHD patients and 480 healthy controls were enrolled. Nine SNPs in CYP19A1, CYP1A1, and CYP1A2 were randomly selected and genotyped using the Agena MassARRAY platform. Logistic regression analysis was used for the relationship between selected SNPs and CHD susceptibility by calculating odds ratios (OR) with 95% confidence intervals (CI) adjusted for age and gender. The distribution of clinical characteristics in different genotypes was evaluated by one-way analysis of variance (ANOVA). CYP1A2 rs2470890 TT genotype had a higher CHD risk compared with CC genotype (OR = 3.06, p = 0.032) or CC-CT genotype (OR = 3.04, p = 0.033). Moreover, the contribution of CYP19A1 and CYP1A2 polymorphisms to CHD susceptibility was associated with age, gender, and clinical phenotypes (course of the disease and Gensini score). Besides, CYP1A2 rs762551 was related to serum levels of red blood cell, triglyceride, total cholesterol, and low-density lipoprotein cholesterol (LDL-C, p < 0.05). Our findings provided scientific evidence about CYP19A1, CYP1A1, and CYP1A2 polymorphisms on CHD incidence.

Neutrophil degranulation and myocardial infarction.

Myocardial infarction (MI) is one of the most common cardiac emergencies with high morbidity and is a leading cause of death worldwide. Since MI could develop into a life-threatening emergency and could also seriously affect the life quality of patients, continuous efforts have been made to create an effective strategy to prevent the occurrence of MI and reduce MI-related mortality. Numerous studies have confirmed that neutrophils play important roles in inflammation and innate immunity, which provide the first line of defense against microorganisms by producing inflammatory cytokines and chemokines, releasing reactive oxygen species, and degranulating components of neutrophil cytoplasmic granules to kill pathogens. Recently, researchers reported that neutrophils are closely related to the severity and prognosis of patients with MI, and neutrophil to lymphocyte ratio in post-MI patients had predictive value for major adverse cardiac events. Neutrophils have been increasingly recognized to exert important functions in MI. Especially, granule proteins released by neutrophil degranulation after neutrophil activation have been suggested to involve in the process of MI. This article reviewed the current research progress of neutrophil granules in MI and discusses neutrophil degranulation associated diagnosis and treatment strategies. Video abstract Neutrophils played a crucial role throughout the process of MI, and neutrophil degranulation was the crucial step for the regulative function of neutrophils. Both neutrophils infiltrating and neutrophil degranulation take part in the injury and repair process immediately after the onset of MI. Since different granule subsets (e g. MPO, NE, NGAL, MMP-8, MMP-9, cathelicidin, arginase and azurocidin) released from neutrophil degranulation show different effects through diverse mechanisms in MI. In this review, we reviewed the current research progress of neutrophil granules in MI and discusses neutrophil degranulation associated diagnosis and treatment strategies. Myeloperoxidase (MPO); Neutrophil elastase (NE); Neutrophil gelatinase-associated lipocalin (NGAL); Matrix metalloproteinase 8 (MMP-8); Matrix metalloproteinase 9 (MMP-9).

By restoring autophagic flux and improving mitochondrial function, corosolic acid protects against Dox-induced cardiotoxicity.

Despite effective anticancer effects, the use of doxorubicin (Dox) is limited due to its side effects as cardiotoxicity. Corosolic acid (CRA) is a pentacyclic triterpene acid isolated from Lagerstroemia speciosa L. (Banaba) leaves, and it has also been shown to improve myocardial hypertrophy and myocardial infarction which expected to be used in clinical pharmaceuticals. The purpose of this study was to explore whether CRA can improve myocardial injury caused by Dox and to clarify potential mechanisms. C57 BL/6J mice and AMPKα2 knockout mice were given a single intraperitoneal (i.p.) injection of Dox (5 mg/kg) every week for 4 weeks, while normal saline (NS) was used as control. Mice were given CRA (10 mg/kg or 20 mg/kg) or equal volumes of normal saline daily after the first time i.p. injection of Dox. After 4 weeks, echocardiography, gravimetric, hemodynamic, histological, and biochemical analyses were conducted. After Dox injury, compared with the control group, CRA increased the survival rate of mice, improved the cardiac function, decreased the oxidative stress, and reduced the apoptosis. CRA may function by promoting transcription factor EB (TFEB) nuclear translocation and thus restoring autophagic flux. We also observed that CRA protected mitochondrial structure and function, which may benefit from oxidative stress reduction or TFEB activation. In vitro, the protective effect of CRA is reversed by TFEB deletion. Then, we evaluated the expression of AMPKα2/mTOR C1 signaling pathway, the main pathway of TFEB activation. In vivo and in vitro, CRA promoted TFEB nuclear translocation by activating AMPKα2/mTOR C1 signaling, while ablating AMPKα2 reversed these results and accompanied with a decrease in the ability of CRA to resist Dox-induced cardiotoxicity. Thus, we suggested that CRA activated TFEB in an AMPKα2-dependent manner to protect against Dox cardiotoxicity. This study confirms the role and mechanism of CRA in the treatment of Dox-induced cardiac injury. Dox-induced damage to autophagy includes autophagosomes maturation disorders and autophagolysosomes acidification defects, CRA restored autophagic flux, and promoted lysosomal degradation by activating TFEB in an AMPKα2-depended manner, stabilized mitochondrial function, ultimately protected against Dox-induced cardiotoxicity.

Lupeol protects against cardiac hypertrophy via TLR4-PI3K-Akt-NF-κB pathways.

Inflammation and apoptosis are main pathological processes that lead to the development of cardiac hypertrophy. Lupeol, a natural triterpenoid, has shown anti-inflammatory and anti-apoptotic activities as well as potential protective effects on cardiovascular diseases. In this study we investigated whether lupeol attenuated cardiac hypertrophy and fibrosis induced by pressure overload in vivo and in vitro, and explored the underlying mechanisms. Cardiac hypertrophy was induced in mice by transverse aortic constriction (TAC) surgery, and in neonatal rat cardiomyocytes (NRCMs) by stimulation with phenylephrine (PE) in vitro. We showed that administration of lupeol (50 mg ·kg-1· d-1, i.g., for 4 weeks) prevented the morphological changes and cardiac dysfunction and remodeling in TAC mice, and treatment with lupeol (50 µg/mL) significantly attenuated the hypertrophy of PE-stimulated NRCMs, and blunted the upregulated hypertrophic markers ANP, BNP, and ß-MHC. Furthermore, lupeol treatment attenuated the apoptotic and inflammatory responses in the heart tissue. We revealed that lupeol attenuated the inflammatory responses including the reduction of inflammatory cytokines and inhibition of NF-κB p65 nuclear translocation, which was mediated by the TLR4-PI3K-Akt signaling. Administration of a PI3K/Akt agonist 740 Y-P reversed the protective effects of lupeol in TAC mice as well as in PE-stimulated NRCMs. Moreover, pre-treatment with a TLR4 agonist RS 09 abolished the protective effects of lupeol and restored the inhibition of PI3K-Akt-NF-κB signaling by lupeol in PE-stimulated NRCMs. Collectively, our results demonstrate that the lupeol protects against cardiac hypertrophy via anti-inflammatory mechanisms, which results from inhibiting the TLR4-PI3K-Akt-NF-κB signaling.

Tax1 banding protein 1 exacerbates heart failure in mice by activating ITCH-P73-BNIP3-mediated cardiomyocyte apoptosis.

Tax1 banding protein 1 (Tax1bp1) was originally identified as an NF-κB regulatory protein that participated in inflammatory, antiviral and innate immune processes. Tax1bp1 also functions as an autophagy receptor that plays a role in autophagy. Our previous study shows that Tax1bp1 protects against cardiomyopathy in STZ-induced diabetic mice. In this study we investigated the role of Tax1bp1 in heart failure. Pressure overload-induced heart failure model was established in mice by aortic banding (AB) surgery, and angiotensin II (Ang II)-induced heart failure model was established by infusion of Ang II through osmotic minipump for 4 weeks. We showed that the expression levels of Tax1bp1 in the heart were markedly increased 2 and 4 weeks after AB surgery. Knockdown of Tax1bp1 in mouse hearts significantly ameliorated both AB- and Ang II infusion-induced heart failure parameters. On the contrary, AB-induced heart failure was aggravated in cardiac-specific Tax1bp1 transgenic mice. Similar results were observed in neonatal rat cardiomyocytes (NRCMs) under Ang II insult. We demonstrated that the pro-heart failure effect of Tax1bp1 resulted from its interaction with the E3 ligase ITCH to promote the transcription factor P73 ubiquitination and degradation, causing enhanced BCL2 interacting protein 3 (BNIP3)-mediated cardiomyocyte apoptosis. Knockdown ITCH or BNIP3 in NRCMs significantly reduced Ang II-induced apoptosis in vitro. Similarly, BNIP3 knockdown attenuated heart failure in cardiac-specific Tax1bp1 transgenic mice. In the left ventricles of heart failure patients, Tax1bp1 expression level was significantly increased; Tax1bp1 gene expression was negatively correlated with left ventricular ejection fraction in heart failure patients. Collectively, the Tax1bp1 increase in heart failure enhances ITCH-P73-BNIP3-mediated cardiomyocyte apoptosis and induced cardiac injury. Tax1bp1 may serve as a potent therapeutic target for the treatment of heart failure.• Cardiac Tax1bp1 transgene mice were more vulnerable to cardiac dysfunction under stress.• Cardiac Tax1bp1 transgene mice were more vulnerable to cardiac dysfunction under stress.• Knockout of Tax1bp1 in mouse hearts ameliorated heart failure induced by pressure overload.• Tax1bp1 interacts with the E3 ligase Itch to promote P73 ubiquitination and degradation, causing enhanced BNIP3-mediated apoptosis.• Tax1bp1 may become a target of new therapeutic methods for treating heart failure.

TMEM173 protects against pressure overload-induced cardiac hypertrophy by modulating autophagy.

TMEM173 has been reported to participate in endoplasmic reticulum stress, inflammation and immunology, all of which closely involved with cardiac hypertrophy. But its role in autophagy is not fully figured out. In our research, Tmem173 global knockout (KO) mice manifested more deteriorated hypertrophy, fibrosis, inflammatory infiltration and cardiac malfunction compared with wild type C57BL/6 mice after 6 weeks of transverse aortic constriction. And KO mice showed inhibited autophagosome degradation in myocardium observed under transmission electron microscope and in protein level. In in vitro experiments conducted in neonatal rat cardiomyocytes under phenylephrine treatment, the abundance of Tmem173 gene was negatively related to the abundance of LC3-Ⅱ and the number of red and yellow fluorescent dots, of which reflected the capacity of autophagosome degradation. These results indicated that TMEM173 might be a promoter of autophagic flux and protected against pressure overload-induced cardiac hypertrophy. It may serve as a potential therapeutic target for cardiac hypertrophy in the future.

Endothelial ERG alleviates cardiac fibrosis via blocking endothelin-1-dependent paracrine mechanism.

Cardiac endothelium communicates closely with adjacent cardiac cells by multiple cytokines and plays critical roles in regulating fibroblasts proliferation, activation, and collagen synthesis during cardiac fibrosis. E26 transformation-specific (ETS)-related gene (ERG) belongs to the ETS transcriptional factor family and is required for endothelial cells (ECs) homeostasis and cardiac development. This study aims at investigating the potential role and molecular basis of ERG in fibrotic remodeling within the adult heart. We observed that ERG was abundant in murine hearts, especially in cardiac ECs, but decreased during cardiac fibrosis. ERG knockdown within murine hearts caused spontaneously cardiac fibrosis and dysfunction, accompanied by the activation of multiple Smad-dependent and independent pathways. However, the direct silence of ERG in cardiac fibroblasts did not affect the expression of fibrotic markers. Intriguingly, ERG knockdown in human umbilical vein endothelial cells (HUVECs) promoted the secretion of endothelin-1 (ET-1), which subsequently accelerated the proliferation, phenotypic transition, and collagen synthesis of cardiac fibroblasts in a paracrine manner. Suppressing ET-1 with either a neutralizing antibody or a receptor blocker abolished ERG knockdown-mediated deleterious effect in vivo and in vitro. This pro-fibrotic effect was also negated by RGD (Arg-Gly-Asp)-peptide magnetic nanoparticles target delivery of ET-1 small interfering RNA to ECs in mice. More importantly, we proved that endothelial ERG overexpression notably prevented pressure overload-induced cardiac fibrosis. Collectively, endothelial ERG alleviates cardiac fibrosis via blocking ET-1-dependent paracrine mechanism and it functions as a candidate for treating cardiac fibrosis. • ERG is abundant in murine hearts, especially in cardiac ECs, but decreased during fibrotic remodeling. • ERG knockdown causes spontaneously cardiac fibrosis and dysfunction. • ERG silence in HUVECs promotes the secretion of endothelin-1, which in turn activates cardiac fibroblasts in a paracrine manner. • Endothelial ERG overexpression prevents pressure overload-induced cardiac fibrosis.

Fibronectin type III domain-containing 5 in cardiovascular and metabolic diseases: a promising biomarker and therapeutic target.

Cardiovascular and metabolic diseases are the leading causes of death and disability worldwide and impose a tremendous socioeconomic burden on individuals as well as the healthcare system. Fibronectin type III domain-containing 5 (FNDC5) is a widely distributed transmembrane glycoprotein that can be proteolytically cleaved and secreted as irisin to regulate glycolipid metabolism and cardiovascular homeostasis. In this review, we present the current knowledge on the predictive and therapeutic role of FNDC5 in a variety of cardiovascular and metabolic diseases, such as hypertension, atherosclerosis, ischemic heart disease, arrhythmia, metabolic cardiomyopathy, cardiac remodeling, heart failure, diabetes mellitus, and obesity.

Matrine attenuates pathological cardiac fibrosis via RPS5/p38 in mice.

Pathological cardiac fibrosis is a common feature in multiple cardiovascular diseases that contributes to the occurrence of heart failure and life-threatening arrhythmias. Our previous study demonstrated that matrine could attenuate doxorubicin-induced oxidative stress and cardiomyocyte apoptosis. In this study, we investigated the effect of matrine on cardiac fibrosis. Mice received aortic banding (AB) operation or continuous injection of isoprenaline (ISO) to generate pathological cardiac fibrosis and then were exposed to matrine lavage (200 mg·kg-1·d-1) or an equal volume of vehicle as the control. We found that matrine lavage significantly attenuated AB or ISO-induced fibrotic remodeling and cardiac dysfunction. We also showed that matrine (200 µmol/L) significantly inhibited the proliferation, migration, collagen production, and phenotypic transdifferentiation of cardiac fibroblasts. Mechanistically, matrine suppressed p38 activation in vivo and in vitro, and overexpression of constitutively active p38 completely abolished the protective effects of matrine. We also demonstrated that ribosomal protein S5 (RPS5) upregulation was responsible for matrine-mediated inhibition on p38 and fibrogenesis. More importantly, matrine was capable of ameliorating preexisting cardiac fibrosis in mice. In conclusion, matrine treatment attenuates cardiac fibrosis by regulating RPS5/p38 signaling in mice, and it might be a promising therapeutic agent for treating pathological cardiac fibrosis.

6-Gingerol protects against cardiac remodeling by inhibiting the p38 mitogen-activated protein kinase pathway.

6-Gingerol, a pungent ingredient of ginger, has been reported to possess anti-inflammatory and antioxidant activities, but the effect of 6-gingerol on pressure overload-induced cardiac remodeling remains inconclusive. In this study, we investigated the effect of 6-gingerol on cardiac remodeling in in vivo and in vitro models, and to clarify the underlying mechanisms. C57BL/6 mice were subjected to transverse aortic constriction (TAC), and treated with 6-gingerol (20 mg/kg, ig) three times a week (1 week in advance and continued until the end of the experiment). Four weeks after TAC surgery, the mice were subjected to echocardiography, and then sacrificed to harvest the hearts for analysis. For in vitro study, neonatal rat cardiomyocytes and cardiac fibroblasts were used to validate the protective effects of 6-gingerol in response to phenylephrine (PE) and transforming growth factor-ß (TGF-ß) challenge. We showed that 6-gingerol administration protected against pressure overload-induced cardiac hypertrophy, fibrosis, inflammation, and dysfunction in TAC mice. In the in vitro study, we showed that treatment with 6-gingerol (20 µM) blocked PE-induced-cardiomyocyte hypertrophy and TGF-ß-induced cardiac fibroblast activation. Furthermore, 6-gingerol treatment significantly decreased mitogen-activated protein kinase p38 (p38) phosphorylation in response to pressure overload in vivo and extracellular stimuli in vitro, which was upregulated in the absence of 6-gingerol treatment. Moreover, transfection with mitogen-activated protein kinase kinase 6 expressing adenoviruses (Ad-MKK6), which specifically activated p38, abolished the protective effects of 6-gingerol in both in vitro and in vivo models. In conclusion, 6-gingerol improves cardiac function and alleviates cardiac remodeling induced by pressure overload in a p38-dependent manner. The present study demonstrates that 6-gingerol is a promising agent for the intervention of pathological cardiac remodeling.

Cardiac Biomarker Abnormalities Are Closely Related to Prognosis in Patients with COVID-19.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is erupting and spreading globally. Cardiovascular complications secondary to the infection have caught notice. This study aims to delineate the relationship of cardiac biomarkers and outcomes in severe cases of corona virus disease 2019 (COVID-19). One hundred forty-eight critically ill adult patients with COVID-19 were enrolled. From these patients, the demographic data, symptoms, cardiac biomarkers, treatments, and clinical outcomes were collected. Data were compared between survivors and non-survivors. Four patients in the non-survivor group were selected, and their cardiac biomarkers were collected and analyzed. Among the 148 patients, the incidence of cardiovascular complications was 19 (12.8%). Five of them were survivors (5.2%), and 14 of them were non-survivors (26.9%). Compared with the survivors, the non-survivors had higher levels of high-sensitivity cardiac troponin I, creatine kinase isoenzyme-MB, myoglobin, and N-terminal pro-brain natriuretic peptide (P < 0.05). The occurrence of cardiovascular events began at 11-15 days after the onset of the disease and reached a peak at 14-20 days. COVID-19 not only is a respiratory disease but also causes damage to the cardiovascular system. Cardiac biomarkers have the potential for early warning and prognostic evaluation in patients with COVID-19. It is recommended that cardiac biomarker monitoring in patients with COVID-19 should be initiated at least from the 11th day of the disease course.

TLR9 deficiency alleviates doxorubicin-induced cardiotoxicity via the regulation of autophagy.

Doxorubicin is a commonly used anthracycline chemotherapeutic drug. Its application for treatment has been impeded by its cardiotoxicity as it is detrimental and fatal. DNA damage, cardiac inflammation, oxidative stress and cell death are the critical links in DOX-induced myocardial injury. Previous studies found that TLR9-related signalling pathways are associated with the inflammatory response of cardiac myocytes, mitochondrial dysfunction and cardiomyocyte death, but it remains unclear whether TLR9 could influence DOX-induced heart injury. Our current data imply that DOX-induced cardiotoxicity is ameliorated by TLR9 deficiency both in vivo and in vitro, manifested as improved cardiac function and reduced cardiomyocyte apoptosis and oxidative stress. Furthermore, the deletion of TLR9 rescued DOX-induced abnormal autophagy flux in vivo and in vitro. However, the inhibition of autophagy by 3-MA abolished the protective effects of TLR9 deletion on DOX-induced cardiotoxicity. Moreover, TLR9 ablation suppressed the activation of p38 MAPK during DOX administration and may promote autophagy via the TLR9-p38 MAPK signalling pathway. Our study suggests that the deletion of TLR9 exhibits a protective effect on doxorubicin-induced cardiotoxicity by enhancing p38-dependent autophagy. This finding could be used as a basis for the development of a prospective therapy against DOX-induced cardiotoxicity.

Combination treatment of perifosine and valsartan showed more efficiency in protecting against pressure overload induced mouse heart failure.

The optimum strategy for heart failure (HF) treatment has yet to be elucidated. This study intended to test the benefit of a combination of valsartan (VAL) and perifosine (PER), a specific AKT inhibitor, in protecting against pressure overload induced mouse HF. Mouse were subjected to aortic banding (AB) surgery to establish HF models and then were given vehicle (HF), VAL (50 mg/kg/d), PER (30 mg/kg/d) or combination of VAL and PER for 4 weeks. Mouse with sham surgery treated with VEH were used for control (VEH). VAL or PER treatment could significantly alleviate mouse heart weight, attenuate cardiac fibrosis and improve cardiac function. The combination treatment of VAL and PER presented much better benefit compared with VAL or PER group respectively. PER treatment significantly inhibited AKT/GSK3ß/mTORC1 signaling. Besides the classic AT1 inhibition, VAL treatment significantly inhibited MAPK (ERK1/2) signaling. Furthermore, VAL and PER treatment could markedly prevent neonatal rat cardiomyocyte hypertrophy and the activation of neonatal rat cardiac fibroblast. Combination of VAL and PER also presented superior beneficial effects than single treatment of VAL or PER in vitro experiments respectively. This study presented that the combination of valsartan and PER may be a potential treatment for HF prevention.

The protective effect of high mobility group protein HMGA2 in pressure overload-induced cardiac remodeling.

High mobility group protein AT-hook 2 (HMGA2), an architectural transcription factor, has previously been reported to play an essential role in regulating the expression of many genes through architectural remodeling processes. However, the effects of HMGA2 on cardiovascular disease, especial cardiac remodeling, is unclear. This study was aimed at investigating the functional role of HMGA2 in pressure overload-induced cardiac remodeling. Mice that were subjected to aortic banding (AB) for 8 weeks developed myocardial hypertrophy and cardiac dysfunction, which were associated with altered expression of HMGA2. Cardiac-specific expression of the human HMGA2 gene in mice with an adeno-related virus 9 delivery system ameliorated cardiac remodeling and improve cardiac function in response to pressure overload by activating PPARγ/NRF2 signaling. Knockdown of HMGA2 by AAV9-shHMGA2 accelerated cardiac remodeling after 1 weeks of AB surgery. Additionally, knockdown of heart PPARγ largely abolished HMGA2 overexpression-mediated cardioprotection. HMGA2-mediated cardiomyocyte protection was largely abrogated by knocking down NRF2 and inhibiting PPARγ in cardiomyocytes. PPARγ activation was mediated by C/EBPß, which directly interacted with HMGA2. Knocking down C/EBPß offset the effects of HMGA2 on PPARγ activation and cardioprotection. These findings show that the overexpression of HMGA2 ameliorates the remodeling response to pressure overload, and they also imply that the upregulation of HMGA2 may become a treatment strategy in cardiac pathologies.

Zingerone attenuates aortic banding-induced cardiac remodelling via activating the eNOS/Nrf2 pathway.

Cardiac remodelling refers to a series of changes in the size, shape, wall thickness and tissue structure of the ventricle because of myocardial injury or increased pressure load. Studies have shown that cardiac remodelling plays a significant role in the development of heart failure. Zingerone, a monomer component extracted from ginger, has been proven to possess various properties including antioxidant, anti-inflammatory, anticancer and antidiabetic properties. As oxidative stress and inflammation contribute to acute and chronic myocardial injury, we explored the role of zingerone in cardiac remodelling. Mice were subjected to aortic banding (AB) or sham surgery and then received intragastric administration of zingerone or saline for 25 days. In vitro, neonatal rat cardiomyocytes (NRCMs) were treated with zingerone (50 and 250 µmol/L) when challenged with phenylephrine (PE). We observed that zingerone effectively suppressed cardiac hypertrophy, fibrosis, oxidative stress and inflammation. Mechanistically, Zingerone enhanced the nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/antioxidant response element (ARE) activation via increasing the phosphorylation of endothelial nitric oxide synthase (eNOS) and nitric oxide (NO) production. Additionally, we used Nrf2-knockout (KO) and eNOS-KO mice and found that Nrf2 or eNOS deficiency counteracts these cardioprotective effects of zingerone in vivo. Together, we concluded that zingerone may be a potent treatment for cardiac remodelling that suppresses oxidative stress via the eNOS/Nrf2 pathway.