Enalapril attenuates endoplasmic reticulum stress and mitochondrial injury induced by myocardial infarction via activation of the TAK1/NFAT pathway in mice

ER stress improvement by aerobic training or enalapril differently ameliorates pathological cardiac remodeling in obese mice

Overactivation of the classic arm of the renin-angiotensin system (RAS) is one of the main mechanisms involved in obesity-related cardiac remodeling, and a possible relationship between RAS and ER stress in the cardiovascular system have been described. Thus, the aim of this study is to evaluate if activating the protective arm of the RAS by ACE inhibition or aerobic exercise training could overturn diet-induced pathological cardiac hypertrophy by attenuating ER stress. Male C57BL/6 mice were fed a control (SC) or a high-fat diet (HF) for 16 weeks. In the 8th week, HF-fed animals were randomly divided into HF, enalapril treatment (HF-En), and aerobic exercise training (HF-Ex) groups. Body mass (BM), food and energy intake, plasma analyzes, systolic blood pressure (SBP), physical conditioning, and plasma ACE and ACE2 activity were evaluated. Cardiac morphology, and protein expression of hypertrophy, cardiac metabolism, RAS, and ER stress markers were assessed. Data presented as mean ± standard deviation and analyzed by one-way ANOVA with Holm-Sidak post-hoc. HF group had increased BM and SBP, and developed pathological concentric cardiac hypertrophy, with overactivation of the classic arm of the RAS, and higher ER stress. Both interventions reverted the increase in BM, and SBP, and favored the protective arm of the RAS. Enalapril treatment improved pathological cardiac hypertrophy with partial reversal of the concentric pattern, and slightly attenuated cardiac ER stress. In contrast, aerobic exercise training induced physiological eccentric cardiac hypertrophy, and fully diminished ER stress.

Circ-SWT1 Ameliorates H2O2-Induced Apoptosis, Oxidative Stress and Endoplasmic Reticulum Stress in Cardiomyocytes via miR-192-5p/SOD2 Axis

Acute myocardial infarction (AMI) is a most serious cardiovascular disease. Increasing findings have indicated that circular RNAs (circRNAs) serve as competent biomarkers in the process of AMI. Herein, our study aimed to probe the functions of circ-SWT1 in cardiomyocyte injury after AMI. H₂O₂-induced human cardiomyocyte cell line AC16 were used for expression and function analyses. The levels of genes and proteins were detected by qRT-PCR and western blotting. Cell apoptosis was analyzed by flow cytometry and caspase3 activity analysis. The oxidative stress injury was evaluated by detecting the levels of reactive oxygen species (ROS), malondialdehyde and superoxide dismutase (SOD). Western blotting was used to detect the expressions of apoptosis-related markers and endoplasmic reticulum stress (ERS) markers. Dual-luciferase reporter, RIP and pull-down assays were applied to confirm the interaction between miR-192-5p and circ-SWT1 or SOD2. H₂O₂ treatment significantly decreased circ-SWT1 expression in cardiomyocytes, functionally, ectopic expression of circ-SWT1 attenuated H₂O₂-triggered apoptosis, oxidative stress and endoplasmic reticulum (ER) stress in cardiomyocytes in vitro. Mechanistically, circ-SWT1 competitively bound to miR-192-5p to relieve the repression of miR-192-5p on its target SOD2. Further rescue experiments showed that miR-192-5p upregulation reversed the inhibitory effects of circ-SWT1 on H₂O₂-induced cardiomyocyte injury. Moreover, miR-192-5p inhibition protected cardiomyocytes against H₂O₂-evoked apoptosis, oxidative stress and ER stress, which were abolished by SOD2 silencing. Circ-SWT1 ameliorates H₂O₂-induced apoptosis, oxidative stress and ER stress in cardiomyocytes via miR-192-5p/SOD2 axis, suggesting the potential involvement of circ-SWT1 in AMI process.

Shenqi Lixin Decoction improves cardiac function in rats with adriamycin-induced heart failure through modulation of PGC-1α and mitochondrial apoptosis pathway

Background

Heart failure (HF) is a complex clinical syndrome and a serious manifestation or late stage of various heart diseases. This study aimed to explore the protective effects and underlying mechanisms of Shenqi Lixin Decoction (SQLXD) in HF.

Methods

A HF rat model was induced by intraperitoneal injection of adriamycin (3 mg/kg in the first 3 weeks, 2 mg/kg in the next 3 weeks, once a week, subcutaneous injection, 6 weeks cumulative dose is 15 mg/kg). After 4 weeks of intragastric administration of SQLXD (9.975, 19.95, 39.90 g/kg, once a day, gavage), the indexes of cardiac function were measured by cardiac color Doppler ultrasound, the cardiac muscle structure and pathological changes were observed by transmission electron microscope, hematoxylin-eosin (HE) staining and Masson. The plasma N-terminal B-type natriuretic peptide (NT-proBNP) level and myocardial tissue adenosine triphosphate (ATP) content were detected by ELISA. FITC detected the cardiomyocyte apoptosis rate (CMAR) labeled Annexin V/PI. Expression of B cell lymphoma factor 2 (Bcl-2), Bcl-2 associated X (Bax), cysteine protease-3 (Caspase-3), and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) mRNA in myocardial tissue were detected by real-time PCR (RT-PCR). The expression of Bcl-2, Bax, Caspase-3 and P53 protein in myocardial tissue were detected by Western blot.

Results

Compared to the normal group, left ventricular end systolic diameter (LVSD), left ventricular end diastolic diameter (LVDD), CMAR and the expression of P53 protein, mRNA and protein of Bax and Caspase-3 were significantly increased in model group, while left ventricular ejection fraction (LVEF), left ventricular fractional shortening (LVFS), stroke volume (SV) and the expression of Bcl-2 protein, mRNA of PGC-1α and Bcl-2 were significantly reduced. Compared to the model group, LVSD, LVDD, CMAR and the expressions of P53 protein, mRNA and protein of Bax and Caspase-3 in the medium and high dose SQLXD groups and the control group were significantly decreased, while LVEF, LVFS, SV and the expression of Bcl-2 protein, mRNA of PGC-1α and Bcl-2 were obviously increased. Pathological findings by transmission electron microscope, Masson, and HE staining all revealed protective effects of SQLXD on heart.

Conclusions

SQLXD can effectively protect HF rats' hearts. The potential mechanism may be related to the modulation of the expression of PGC-1α and the mitochondrial apoptosis pathway.