Extracellular vesicles derived from human bone marrow mesenchymal stem cells protect rats against acute myocardial infarction-induced heart failure.

Extracellular vesicles (EVs) derived from human bone marrow mesenchymal stem cells (BMSCs) are suggested to promote angiogenesis in a rat model of acute myocardial infarction (AMI). This study aimed to explore the underlying mechanism of BMSCs-EVs in AMI-induced heart failure (HF). BMSCs were isolated and verified, and EVs were purified and identified. After establishment of AMI-induced HF models, rats were treated with BMSCs-EVs and/or overexpressing (ov)/knocking down (kd) bone morphogenetic protein 2 (BMP2). Cardiac function, myocardial histopathological changes, angiogenesis, and vascular regeneration density were measured. Levels of pro-angiogenesis factors and cardiomyocyte apoptosis were detected. The viability and angiogenesis of hypoxic human umbilical vein endothelial cells (HUVECs) were measured. After BMSCs-EV treatment, the cardiac function of HF rats was improved, myocardial fibrosis and inflammatory cell infiltration were decreased, angiogenesis was increased, and cardiomyocyte apoptosis was inhibited. BMP2 was significantly upregulated in the myocardium. Ov-BMP2-BMSCs-EVs alleviated myocardial fibrosis and inflammatory cell infiltration, and promoted angiogenesis of HF rats, and improved the activity and angiogenesis of hypoxic HUVECs, while kd-BMP2-BMSCs-EVs showed limited protection against AMI-induced HF. BMSCs-EVs deliver BMP2 to promote angiogenesis and improve cardiac function of HF rats.

Long non-coding RNA Sox2OT promotes coronary microembolization-induced myocardial injury by mediating pyroptosis.

OBJECTIVE: As a common complication of coronary microembolization (CME), myocardial injury (MI) implies high mortality. Long non-coding RNAs (lncRNAs) are rarely studied in CME-induced MI. Herein, this study intended to evaluate the role of lncRNA Sox2 overlapping transcript (Sox2OT) in CME-induced MI. METHODS: The CME rat models were successfully established by injection of microemboli. Rat cardiac functions and MI were observed by ultrasonic electrocardiogram, HE staining, and HBFP staining. Functional assays were utilized to test the inflammatory responses, oxidative stress, and pyroptosis using reverse transcription quantitative polymerase chain reaction, Western blotting, immunohistochemistry, immunofluorescence, and ELISA. Dual-luciferase reporter gene assay and RNA immunoprecipitation were conducted to clarify the targeting relations between Sox2OT and microRNA (miRNA)-23b and between miR-23b and toll-like receptor 4 (TLR4). RESULTS: Rat CME disrupted the cardiac functions and induced inflammatory responses and oxidative stress, and activated the nuclear factor-kappa B (NF-κB) pathway and pyroptosis (all P < 0.05). An NF-κB inhibitor downregulated the NF-κB pathway, reduced pyroptosis, and relieved cardiomyocyte injury and pyroptosis. Compared with the sham group (1.05 ± 0.32), lncRNA Sox2OT level (4.41 ± 0.67) in the CME group was elevated (P < 0.05). Sox2OT acted as a competitive endogenous RNA (ceRNA) of miR-23b to regulate TLR4. Silencing of Sox2OT favoured miR-23b binding to 3'UTR of TLR4 mRNA leading to suppressed TLR4-mediated NFKB signalling and pyroptosis in myocardial tissues harvested from CME rat models. In addition, miR-23b overexpression could supplement the cytosolic miR-23b reserves to target TLR-4 and partially reverse Sox2OT-mediated pyroptosis in LPS-treated H9C2 cells. CONCLUSIONS: This study supported that silencing Sox2OT inhibited CME-induced MI by eliminating Sox2OT/miR-23b binding and down-regulating the TLR4/NF-κB pathway. This investigation may provide novel insights for the treatment of CME-induced MI.

[Astragalus injection mediates autophagy and myocardial remodeling in rats with ischemic cardiomyopathy through calumenin].

OBJECTIVE: To study the effects of astragalus injection on myocardial remodeling, calumenin and autophagy in rats with ischemic cardiomyopathy. METHODS: Thirty-six male SD rats were divided into normal control group, ischemic cardiomyopathy group and astragalus injection group, 12 in each group. Electrocardiogram (ECG) and echocardiography were performed before operation in three groups. Rats in ischemic cardiomyopathy group and astragalus injection group underwent thoracotomy and ligation of coronary artery for 20 minutes, then thoracic cavity was closed after reperfusion. In the astragalus injection group,10 g/kg body weight of Astragalus injection was injected once a week, four times in total. Four weeks after operation, rats in three groups were executed by echocardiography and their hearts were collected for Hematoxylin-Eosin (HE) staining and Van Gieson (VG) staining to observe myocardial pathological changes. Calumenin, LC3-I, LC3-II expressions and LC3-I/LC3-II ratio were detected by Western blot. RESULTS: Compared with ischemic cardiomyopathy group, the echocardiography and myocardial pathology of rats in astragalus injection group changed obviously, and the expressions of calumenin, LC3-I, LC3-II and LC3-I/LC3-II ratio changed significantly (P＜0.01). CONCLUSION: Astragalus injection has apparent inhibitory effect on ventricular remodeling and autophagy of myocardial cells in rats with ischemic cardiomyopathy, which may be mediated by calumenin.

Trapidil determines the fate of RHF rats through inhibition of ER stress.

Pulmonary arterial hypertension is a fatal disease, especially when it causes right heart failure (RHF). However, it is difficult to treat. It has been reported that trapidil (Tra) can improve the redox balance and cardiac conditions. In this study, we investigated the effect of Tra on RHF induced by monocrotaline (MCT) in rats. Male Wistar rats were treated with MCT or Tra. Treatment lasted 28 days, then rats were euthanized after echocardiography and catheterization. Subsequently, lungs and right ventricular myocardia were evaluated by hematoxylin and eosin, Masson, and TUNEL staining. Protein expression was detected by western blotting. We found remarkably expanded right ventricle end-diastolic volume, decreased partial pressure of oxygen (PaO2), increased partial pressure of carbon dioxide (PaCO2), right ventricular systolic pressure, mean pulmonary arterial pressure, lung/body weight, and liver/body weight in the RHF rat group, as well as increases in the apoptosis rate and the expression of endoplasmic reticulum stress (ERS)-related proteins. However, these changes were significantly inhibited by Tra. Our data suggested that inhibition of ERS is essential for improving RHF, and that therapeutic intervention of Tra in RHF rats works by reducing ERS.

[The relationship between myocardial remodeling and endoplasmic reticulum stress and autophagy in rats with ischemic cardiomyopathy].

OBJECTIVE: To study the relationship between myocardial remodeling and endoplasmic reticulum stress and autophagy in rats with ischemic cardiomyopathy. METHODS: Thirty-six male SD rats were divided into normal control group, sham-operated group and ischemic cardiomyopathy group (n=12). Echocardiography was performed before operation in three groups. Rats in sham-operated group closed their thoracic cavity without ligation of coronary artery after thoracotomy. The rats in ischemic cardiomyopathy group were closed their thoracic cavity after ligating of coronary artery for 20 minutes and recovered reperfusion. After operation for 4 weeks, rats in three groups were killed after taking echocardiography. The myocardial tissues were taken for HE staining and Masson staining to observe the pathological changes of myocardium and the expressions of glucose-regulated protein 78 (GRP78), microtubule-associated protein 1 light chain 3- I (LC3-I), microtubule-associated protein 1 light chain 3- II (LC3-II), Bcl-2 interacting protein (Beclin-I) and the ratio of LC3-II/LC3-I were detected by Western blot. RESULTS: Compared with normal group and sham-operated group, ischemic cardiomyopathy rats had significant differences in echocardiography and myocardial pathology; the myocardial array was disordered, myocardial fibrosis was increased, mitochondrial vacuolation was serious. Mean while, the expressions of GRP78, LC3-I, LC3-II, Beclin-I and LC3-II/LC3-I ratio had significant changes. CONCLUSION: Autophagy and endoplasmic reticulum stress may play important roles in myocardial remodeling in rats with ischemic cardiomyopathy.

Astragalus Root dry extract restores connexin43 expression by targeting miR-1 in viral myocarditis.

BACKGROUND: Viral myocarditis is defined as viral infection of myocardial tissue leading to impaired heart function and heart failure. Accumulating evidences have shown that arrhythmia is one of important complicating diseases of viral myocarditis causing increased mortality and morbidity. There are no effective treatment for the viral infection and complicating arrhythmia. PURPOSE: This study investigated the effect and mechanism of Astragalus Root dry extract (ARDE) on arrhythmia induced by CVB3 in mice. METHODS: The mice and HL-1 cells were treated with CVB3 and ARDE. Reciprocal regulation of Cx43 and miR-1 were observed in the CVB3 infected mouse myocardium and culture HL-1 cells. RESULTS: CVB3 IP injection increased immune cell infiltration in mouse left ventricle and caused irregular arrhythmia. ARDE treatment prevented the increase of immune cell infiltration and arrhythmia. Overexpression of miR-1 significantly inhibited both endogenous Cx43 expression and Cx43 3'UTR luciferase activity in HL-1 cells. Mutation of census binding site of +1586-1593 bp not +465-472 bp in Cx43 3'UTR luciferase resulted in abolishment of miR-1 inhibitory effects in HL-1 cells. Loss-of- function of miR-1 restored CVB3-induced Cx43 expression reduction in cultured HL-1 cells. The presence of ARDE attenuated the augmented miR-1 induced by CVB3 infection in vivo and in vitro. CONCLUSION: This study identified that CVB3 infection reduced Cx43 expression by elevating miR-1 level in mouse viral myocarditis. For the first time, ARDE was shown to prevent arrhythmia, and rescue CVB3-induced endogenous Cx43 expression by regulating miR-1 level.

[Effects of total flavonids of astragalus on arrhythmia,endoplasmic reticulum stress in mice with viral myocarditis].

OBJECTIVE: To investigate the effects of total flavonids of astragalus(TFA) on arrhythmia, endoplasmic reticulum stress and connexcin in mice with viral myocarditis and to clarify the mechanisms of TFA against viral myocarditis complicated with arrhythmia. METHODS: Thirty-six male Balb/c mice were randomly divided into control group, viral myocarditis group and total flavonoids group (n=12). The mice of viral myocarditis were intraperitonealy injected with 0.1 ml/day 10-950 TCID CVB3 for 3 days. The mice of TFA group were intraperitoneal injected with 0.1 ml/day 10-950 TCID CVB3 for 3 days and treated with 0.1ml, 20 mg/L TFA by tail vein injection. At the end of the experiment, arrhythmia was detected by electrocardiogram, the heart of mice were stained by HE, the expressions of glucose-regulated protein 78(GRP78), endoplasmic reticulum stress signaling pathway factor activating transcription factor 4(ATF4) and connexcin 43(Cx43) were detected by Western blot. RESULTS: The expressions of GRP78 and ATF4 were increased and the expression of Cx43 was decreased in viral myocarditis, while TFA inhibited these effect of viral myocarditis in heart of mice. CONCLUSIONS: The antiarrhythmic effect of TFA may be related to the alleviation of endoplasmic reticulum stress and the increase of Cx43 expression.

[Effect of Astragalus injection on cardiomyocyte apoptosis, endoplasmic reticulum stress and expression of connexin in cardiomyopathy rats induced by adriamycin].

OBJECTIVES: To investigate the effect of Astragalus injection on cardiomyocyte apoptosis, endoplasmic reticulum stress and connexin protein in cardiomyopathy rats induced by adriamycin. METHODS: Thirty-six male Wister rats were randomly divided into control group (n=12), adriamycin(ADR) group (n=12) and Astragalus group (n=12). The normal saline (10 ml/kg body weight) was injected intraperitoneally in control group rats, ADR (2 mg/kg body weight) was injected intraperitoneally in ADR group rats, ADR (10 ml/kg body weight) and Astragalus injection (10 ml/kg body weight) were injected intraperitoneally in rats of astragalus group, one time a week, totle 3 times. By the end of the 7th week, the left ventricular end-diastolic diameter(LVEDD), left ventricular end-systolic diameter (LVESD) and left ventricular ejection fraction (LVEF) were measured by echocardiography. Then the rats in the three groups were sacrificed and the left ventricle section was stained by HE, Masson, uranyl acetate/lead citrate respectively, the cardiomyopathy and ultrastructural changes were observed under light microscope and transmission electron microscope. The apoptosis of rat cardiomyocyte were analyzed by TUNEL. The expression of connexin Cx43 and p-Cx43 was detected by immunohistochemistry. The expression of glucose-regulated protein 78 (Grp78),activating transcription factor 4 (ATF-4) and C/EBP homologous protein (CHOP) were detected by real time PCR. RESULTS: Compared with control group, LVEDD, LVESD increased and LVEF decreased, myocardial fibers were disordered and edematous, infiltrated by lymphocytes, the mitochondria were destroyed and vacuolized, and the number of cardiomyocyte apoptosis was increased(P<0.01) in ADR group. The expression of Grp78, ATF-4, CHOP and p-Cx43 were increased, and the expression of Cx43 was decreased in ADR group. However, compared with ADR group, LVEDD, LVESD decreased and LVEF increased, the cardiomyopathy and ultrastructural changes were significantly improved, the number of cardiomyocyte apoptosis was significantly decreased (P<0. 01); the expression of Grp78, ATF-4, CHOP and p-Cx43 decreased (P<0.01); the expression of Cx43 increased in Astragalus group (P<0.01). CONCLUSIONS: Astragalus injection may effectively improve the myocardial damage induced by adriamycin, its mechanism may be related to the inhibition of endoplasmic reticulum stress (ERS) and the decrease of phosphorylation of CX43 in cardiomyopathy rats induced by adriamycin.

Freestanding two-dimensional Ni(OH)2 thin sheets assembled by 3D nanoflake array as basic building units for supercapacitor electrode materials.

Freestanding two dimensional (2D) porous nanostructures have great potential in electrical energy storage. In the present work, we reported the first synthesis of two-dimensional (2D) ß-Ni(OH)2 thin sheets (CQU-Chen-Ni-O-H-1) assembled by 3D nanoflake array as basic building units under acid condition by direct hydrothermal decomposition of the mixed solution of nickel nitrate (Ni(NO3)2) and acetic acid (CH3COOH, AA). The unique 3D nanoflake array assembled mesoporous 2D structures endow the thin sheets with a high specific capacitance of 1.78Fcm-2 (1747.5Fg-1) at the current density of 1.02mAcm-2 and good rate capability of 67.4% retain from 1.02 to 10.2mAcm-2. The corresponding assembled asymmetric supercapacitor (ASC) achieves (CQU-Chen-Ni-O-H-1//active carbon (AC)) a high voltage of 1.8V and an energy density of 23.45Whkg-1 with a maximum power density of 9kWkg-1, as well as cycability with 93.6% capacitance retention after 10,000 cycles. These results show the mesoporous thin sheets have great potential for SCs and other energy storage devices.

Ibutilide treatment protects against ER stress induced apoptosis by regulating calumenin expression in tunicamycin treated cardiomyocytes.

BACKGROUND: Ibutilide, a class III antiarrhythmic agent has been shown to be cardioprotective in treating atrial fibrillation, promoting cardioconversion and recently this agent has been shown to protect against ER stress induced apoptosis in cardiomyocytes. In this study we begin to identify the mechanism by which ibutilide exerts its cardioprotection in tunicamycin treated cardiomyocytes. We examined ER stress markers including calumenin; a calcium binding ER chaperone protein that has recently been linked to ER stress in cardiomyocytes, in our treated cells. METHODS: To assess the effect of ibutilide we used the well characterized in vitro model of ER stress induced apoptosis in rat neonatal cardiomyocytes (RNC). RNC were treated with tunicamycin and the degree of ER stress was assessed by quantifying mRNA and protein levels of GRP78, GRP94 and calumenin, and examined the extent of apoptosis by assessing the protein levels of caspase-3/9/12, CHOP, ATF6, p-PERK, spliced XBP-1, the ratio of Bax/Bcl-2 and the percentage of deoxynucleotidyl-transferase- mediated dUTP nick end labeling (TUNEL) positive cells. RESULTS: We demonstrate ibutilide attenuated the up-regulation of ER stress markers GRP78 and GRP94 and rescued the decline in calumenin mRNA and protein levels in tunicamycin treated cardiomyocytes. The up-regulation of apoptotic markers caspase-3, CHOP, ATF6, p-PERK, spliced XBP-1, the ratio of Bax/Bcl-2 and the percentage of TUNEL positive cells were also attenuated after ibutilide treatment while the protein levels of Caspase-9 and Caspase-12 were unaffected. CONCLUSIONS: This study suggests another cardioprotective effect of the antiarrhythmic agent ibutilide whereby pretreatment leads to the attenuation of ER stress induced apoptosis by regulating calumenin expression. This study provides further evidence for the role of calumenin in the cardiomyocyte ER stress response.

Calumenin relieves cardiac injury by inhibiting ERS-initiated apoptosis during viral myocarditis.

Viral myocarditis (VMC) is a common disease causing heart failure (HF) for which no specific treatments are available. As apoptosis of cardiomyoctes is a hallmark of VMC and HF, strategies targeting apoptosis are an effective way of prevention and treatment of HF. Recent studies found endoplasmic reticulum stress (ERS) reaction is a new signal transduction pathway mediating apoptosis. Calumenin protein (CP) is located within the endoplasmic reticulum Ca2+ binding proteins, and is important in ER-initiated apoptosis. The aim of this study was to investigate whether the function of CP was influenced in cardiomyocytes infected by coxsackievirus B3. The expression of CP was down-regulated in cardiomyocytes infected by coxsackievirus B3. TUNEL studies showed that apoptosis was increased in CP-deficient and ΔCP-mutant cardiomyocytes infected by coxsackievirus B3. Additionally, ERS-associated proteins (GRP78, p-PERK, p-eIF2α, ATF4 and CHOP) were up-regulated in coxsackievirus B3-infected CP-deficient and ΔCP-mutant cardiomyocytes compared to wild type control cells. These results suggested ER-initiated apoptosis was induced by coxsackievirus B3-infected cardiomyocytes and caused apoptosis through ER stress. CP can relieve ERS-initiated apoptosis in viral myocarditis.

[Effect of total flavonoids of astragalus on endoplasmic reticulum chaperone, calumenin and connecxin 43 in suckling mouse myocardium with myocarditis caused by coxsackievirus B3].

OBJECTIVE: To investigate the effect of total flavonoids of astragalus on the expression of endoplasmic reticulum chaperone, calumenin and connecxin 43 (CX43) in suckling mouse myocardium with myocarditis caused by coxsackievirus B3 (CVB3). METHODS: The primary culture of suckling mouse myocardium cells were randomly divided into control group, CVB3 infected group and total flavonoids of astragalus group. Firstly, to confirm the identity of the suckling mouse myocardium, α-SMA was monitored by immunohistochemistry method. Then the protein expression changes of endoplasmic reticulum chaperone-glucose regulatory protein 78 ( GRP78), calumenin and CX43 were detected by Western blot. RESULTS: (1) Compared with that of the control group, the GRP78 expression level in CVB3 infected group was improved, the expression levels of calumenin and CX43 were all reduced. (2) Compared with that of CVB3 infected group, GRP78 expression level was decreased, and the expression levels of calumenin and CX43 were increased in total flavonoids of astragalus group. CONCLUSION: CVB3 infection may cause endoplasmic reticulum stress of rat myocardium cells by increasing the expression of GRP78 and decreasing the expression of calumenin and CX43. On the other hand, total flavonoids of astragalus can reduce the expression of GRP78 and increase the expression of calumenin and CX43.The results of this experiment may be closely related to the effects of anti-arrhythmia with viral myocarditis caused by CVB3.

Chebulagic acid inhibits the LPS-induced expression of TNF-α and IL-1ß in endothelial cells by suppressing MAPK activation.

Inflammatory response in the vasculature, including the overexpression of tumor necrosis factor (TNF)-α and interleukin (IL)-1ß, has been demonstrated to increase the risk of thrombosis development. Chebulagic acid (CA) is a key chemical component in the traditional Mongolian anti-thrombotic drug Garidi-13, and has been suggested to exert anti-inflammatory and anti-infective effects. The present study aimed to evaluate the regulatory impact of CA on a number of biological processes, including lipopolysaccharide (LPS)-induced inflammation, LPS-promoted mitogen-activated protein kinase (MAPK) activation and the expression of toll-like receptor (TLR)4 in EA.hy926 human endothelial cells. The results indicated that CA significantly inhibited the LPS-induced upregulation of TNF-α and IL-1ß in a dose- and time-dependent manner. Furthermore, LPS-activated MAPK signaling was inhibited by CA treatment in the EA.hy926 cells. However, TLR4, which serves a key function in LPS-induced inflammation as the receptor of LPS, was not regulated by the CA treatment. In summary, the results of the present study indicate that CA inhibits the LPS-induced promotion of TNF-α and IL-1ß in endothelial cells by suppressing MAPK activation, which may contribute to the anti-thrombotic effect of Garidi-13.