Novel Insights into the Molecular Features and Regulatory Mechanisms of Mitochondrial Dynamic Disorder in the Pathogenesis of Cardiovascular Disease.

Mitochondria maintain mitochondrial homeostasis through continuous fusion and fission, that is, mitochondrial dynamics, which is precisely mediated by mitochondrial fission and fusion proteins, including dynamin-related protein 1 (Drp1), mitofusin 1 and 2 (Mfn1/2), and optic atrophy 1 (OPA1). When the mitochondrial fission and fusion of cardiomyocytes are out of balance, they will cause their own morphology and function disorders, which damage the structure and function of the heart, are involved in the occurrence and progression of cardiovascular disease such as ischemia-reperfusion injury (IRI), septic cardiomyopathy, and diabetic cardiomyopathy. In this paper, we focus on the latest findings regarding the molecular features and regulatory mechanisms of mitochondrial dynamic disorder in cardiovascular pathologies. Finally, we will address how these findings can be applied to improve the treatment of cardiovascular disease.

MicroRNA-208-5p regulates myocardial injury of sepsis mice via targeting SOCS2-mediated NF-κB/HIF-1α pathway.

BACKGROUND: Accumulating evidence has revealed the roles of microRNAs (miRs) in sepsis, hence, the aim of the present study was to investigate whether miR-208a-5p affects sepsis whilst attempting to elucidate the mechanisms by which the suppressors of cytokine signaling 2 (SOCS2)-mediated nuclear factor-kappaB/hypoxia-inducible factor-1α (NF-κB/HIF-1α) pathway is implicated in this process. METHODS: The sepsis model was established by cecal ligation and puncture in mice. Serum levels of myocardial enzyme cardiac Troponin-I (cTnI) and brain natriuretic peptide (BNP) in mice were measured. Malondialdehyde (MDA), lactate dehydrogenase (LDH) activity, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), NF-κB p65, HIF-1α and superoxidedismutase (SOD) activity in myocardial tissues were determined. Furthermore, the swelling degree of mitochondria and the apoptosis of cardiomyocytes was measured. The expression of miR-208a-5p, SOCS2, Bcl-2, Bax, NF-κB p65 and HIF-1α in myocardial tissues of mice were detected. RESULTS: Down-regulation of miR-208a-5p and up-regulation of SOCS2 raised the activity of SOD, while reduced the activity of LDH and MDA and the concentrations of cTnI, BNP, TNF-α, IL-6, NF-κB p65 and HIF-1α in mice with sepsis. Down-regulated miR-208a-5p and up-regulated SOCS2 reduced degree of mitochondria swelling, and suppressed cardiomyocytes apoptosis in mice with sepsis. MiR-208a-5p, NF-κB p65 and HIF-1α expression were raised while SOCS2 expression was depressed in myocardial tissues of mice with sepsis. CONCLUSION: This study suggests that high expression of SOCS2 or inhibition of miR-208a-5p alleviates the myocardial injury of sepsis mice via modulating NF-κB/HIF-1α pathway, which are potential candidate markers and therapeutic targets for sepsis mice.

Combination of melatonin and irisin ameliorates lipopolysaccharide-induced cardiac dysfunction through suppressing the Mst1-JNK pathways.

Despite significant advances in therapies in past decades, the mortality rate of septic cardiomyopathy remains high. The aim of this study is to explore the therapeutic effects of combined treatment using melatonin and irisin in a mouse model of lipopolysaccharide (LPS)-mediated septic cardiomyopathy. Our data found that melatonin and irisin could further attenuate LPS-induced myocardial depression. Molecular investigation illustrated that melatonin and irisin cotreatment sustained cardiomyocyte viability and improved mitochondrial function under LPS stress. Pathway analysis demonstrated that macrophage-stimulating 1 (Mst1), which was significantly activated by LPS, was drastically inhibited by melatonin/irisin cotreatment. Mechanically, Mst1 activated c-Jun N-terminal kinase (JNK) pathway and the latter induced oxidative stress, adenosine triphosphate metabolism disorder, mitochondrial membrane potential reduction, and cardiomyocyte death activation. Melatonin and irisin cotreatment effectively inhibited the Mst1-JNK pathway and, thus, promoted cardiomyocyte survival and mitochondrial homeostasis. Interestingly, Mst1 overexpression abolished the beneficial effects of melatonin and irisin in vivo and in vitro. Altogether, our results confirmed that melatonin and irisin combination treatment could protect heart against sepsis-induced myocardial depression via modulating the Mst1-JNK pathways.