Mitophagy-dependent cardioprotection of resistance training on heart failure.

Resistance exercise is an indispensable mode of exercise rehabilitation for heart failure. Here we elucidate the cardiac effects of resistance training alone or combined with different aerobic trainings on heart failure and explore the critical regulation of mitophagy. The chronic heart failure model was constructed by transverse aortic constriction surgery, followed by 8 wk of resistance training (RT), moderate-intensity continuous training combined with resistance training (MRT), and high-intensity interval training combined with resistance training (HRT), and subsequently analyzed the changes of maximum load, cardiac structure and function, and myocardial mitophagic activity. The role and signaling of mitophagy in exercise protection of heart failure were investigated by knockdown of Hif1α and Parkin genes in primary neonatal cardiomyocytes. RT and especially MRT improved maximum load (P < 0.0001), myocardial morphology and fibrosis (P < 0.0001), reduced left ventricular diameter and enhanced left ventricular systolic function (P < 0.01), and enhanced myocardial mitophagic activity and HIF1α expression (P < 0.05) in heart failure mice. However, HRT had no obvious protective effect on ventricular diameter and function or mitophagy. The abilities of exercise stimulation to regulate reactive oxygen species, adenosine triphosphate, and brain natriuretic peptide were impaired after knockdown of Hif1α and Parkin genes inhibited mitophagy in failing cardiomyocytes (P < 0.05). Different exercise modalities provide discrepant cardiovascular effects on heart failure, and MRT exhibits optimal protection. The HIF1α-Parkin-mitophagy pathway is involved in the protection and regulation of exercise on heart failure.NEW & NOTEWORTHY Impaired myocardial mitophagy is implicated in the pathogenesis of heart failure. Resistance training alone or combined with different aerobic trainings provide discrepant cardiovascular effects on heart failure, and the cardioprotective function depends on HIF1α-Parkin-mitophagy pathway.

Exercise training improves cardiac function and regulates myocardial mitophagy differently in ischaemic and pressure-overload heart failure mice.

NEW FINDINGS: What is the central question of this study? What are the cardioprotective effects of different aerobic exercises on chronic heart failure with different aetiologies, and is mitophagy involved? What is the main finding and its importance? Moderate-intensity continuous training may be the 'optimum' modality for improving cardiac structure and function in ischaemic heart failure, while both moderate-intensity continuous training and high-intensity interval training were suitable for pressure-overload heart failure. Various mitophagy pathways, especially parkin-dependent pathways, participated in the protective effects of exercise on heart failure. ABSTRACT: The cardioprotective effects of different aerobic exercises on chronic heart failure with different aetiologies and whether mitophagy is involved remain elusive. In the current research, left anterior descending ligation and transverse aortic constriction surgeries were used to establish mouse models of heart failure, followed by 8 weeks of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT). The results showed that for ischaemic heart failure MICT significantly improved ejection fraction (P < 0.05) and fractional shortening (P < 0.05), mitigated left ventricular end-systolic dimension (P < 0.01), decreased brain natriuretic peptide (P < 0.0001) and mitigated fibrosis (P < 0.0001), while HIIT only decreased brain natriuretic peptide (P < 0.0001) and fibrosis (P < 0.0001). For pressure-overload heart failure, both MICT and HIIT significantly increased ejection fraction (P < 0.0001) and fractional shortening (MICT: P < 0.001, HIIT: P < 0.0001), and reduced left ventricular end-diastolic and end-systolic dimensions, brain natriuretic peptide (P < 0.0001), and fibrosis (MICT: P < 0.01, HIIT: P < 0.0001); HIIT was even better in reducing brain natriuretic peptide. Myocardial autophagy and mitophagy were compromised in heart failure, and the exercises improved myocardial autophagic flux and mitophagy inconsistently in heart failure with different aetiologies. Significant correlations were found between multiple mitophagy pathways and the cardioprotection of the exercises. Collectively, MICT may be the 'optimum' modality for ischaemic heart failure, while both MICT and HIIT (especially HIIT) were suitable for pressure-overload heart failure. Exercises differently improved myocardial autophagy/mitophagy, and multiple mitophagy-related pathways were closely implicated in cardioprotection of exercises for chronic heart failure.

Crushed/chewed administration of potent P2Y12 inhibitors in ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention: Systematic review and meta-analysis.

Crushed or chewed potent P2Y12 inhibitors are commonly used in the hope of bridging the gap of platelet inhibition in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI). The study aimed to investigate the efficacy and safety of this alternative oral administration strategy by performing a meta-analysis of available randomized clinical trials (RCTs). PubMed, Embase, the Cochrane Library and Web of Science medical literature databases were searched for RCTs comparing crushed/chewed vs. integral administration of loading dose potent P2Y12 inhibitors in patients with STEMI undergoing pPCI with no language restrictions from inception to January 20th, 2021. The primary efficacy endpoints of high on treatment platelet reactivity (HPR) and P2Y12 reaction units (PRU) at 1 hour together with safety and additional clinical endpoints were evaluated by pooled odds ratio (OR) or mean differences (MD) with 95% confidence intervals (95% CI). A total of 973 patents in six RCTs were eligible for analysis, while 876 patients present baseline and procedural characteristics. HPR and PRU at 1 hour were significantly reduced in the group receiving crushed/chewed P2Y12 inhibitors compared with integral tablets (OR 0.28, 95% CI 0.16 to 0.49, P < .0001; MD -60.62, 95% CI -97.06 to -24.19, P = .001, respectively). Safety endpoints of major bleeding (OR 0.54, 95% CI 0.11 to 2.73, P = .46) and any bleeding (OR 0.84, 95% CI 0.43 to 1.64, P = .61), as well as additional clinical endpoints of cardiovascular death, myocardial infarction, and stroke were not affected by the oral administration strategy. In STEMI patients undergoing pPCI, crushed or chewed administration of potent P2Y12 inhibitors are associated with enhanced early platelet inhibition and appear to be safe. The clinical profile transformed from this pharmacodynamic benefit need to be determined by further researches.

Glycoborinine induces apoptosis through mitochondrial pathway in HepG2 cells.

Glycoborinine (GB), a natural carbazole alkaloid isolated from Glycosmis pentaphylla, has been shown to be a potential molecule against cancer cells. In this study, the cell-signaling pathway of its anti-tumor activity was investigated. MTT assay result showed that GB inhibited HepG2 cell proliferation in a dose- and time-dependent manner and 50% inhibiting concentration (IC50) of GB-induced cell death was 39.7 µM for a period of 48 h. GB-induced HepG2 apoptosis was confirmed by Hochest 33258 staining and PI staining. The level of reactive oxygen species (ROS) was measured with H2DCF-DA staining and the change of mitochondrial membrane potential (△Ψ(m)) was analyzed with tetrechloro-tetraethylbenzimidazolcarbocyanine iodide (JC-1) probe. Results showed that GB at 12.5, 25, and 50 µM promoted ROS production. GB induced HepG2 apoptosis through a mitochondrial apoptotic pathway, which was demonstrated by GB-induced increase in the ratio of Bax/Bcl-2, cytochrome C release, the ratio of cleaved caspase-3/procaspase-3, and the ratio of cleaved poly ADP-ribose polymerase (cleaved PARP)/poly ADP-ribose polymerase (PARP). To summarize, this study demonstrated that GB could induce HepG2 apoptosis through the mitochondrial-dependent pathway, which might provide a promising approach to cure liver cancer with GB.

Transforming growth factor beta/Smad3 signaling regulates IRF-7 function and transcriptional activation of the beta interferon promoter.

The rapid induction of alpha interferon (IFN-alpha) and IFN-beta expression plays a critical role in the innate immune response against viral infection. We studied the effects of transforming growth factor beta (TGF-beta) and its intracellular effectors, the Smads, on the function of IRF-7, an essential transcription factor for IFN-alpha and -beta induction. IRF-7 interacted with Smads, and IRF-7, but not IRF-3, cooperated with Smad3 to activate IFN-beta transcription. This transcriptional cooperation occurred at the IRF-binding sequences in the IFN-beta promoter, and dominant-negative interference with TGF-beta receptor signaling and Smad3 function decreased IRF-7-mediated transcription. Furthermore, elimination of Smad3 expression in Smad3(-/-) fibroblasts delayed and decreased double-stranded RNA-induced expression of endogenous IFN-beta, whereas restoration of Smad3 expression enhanced IFN-beta induction. The IRF-7-Smad3 cooperativity resulted from the regulation of the transactivation activity of IRF-7 by Smad3, and dominant-negative interference with Smad3 function decreased IRF-7 activity. Consistent with the regulation by Smad3, the transcriptional activity of IRF-7 depended on and was regulated by TGF-beta signaling. Our studies underscore a role of TGF-beta/Smad3 signaling in IRF-7-mediated induction of IFN-beta expression.