Abstract

BACKGROUND: Sepsis is defined as a systemic inflammatory response syndrome caused by an infection (suspicious or confirmed). Its essence is inflammatory mediators and cytokines mediated by host immune response. The present study aimed to investigate the role of Periplaneta americana extracts (XML) on PTEN-induced kinase 1 (PINK1)/Parkin mediated mitophagy in cardiomyocyte injury by sepsis.

MATERIAL AND METHODS: H9C2 cells were cultured and transfected with Mdivi-1 and Atg7 siRNA. The cell viability and drug toxicity were detected using Cell Counting Kit-8 assay. ELISA (enzyme-linked immunosorbent assay) was used to assess cardiac injury factors and inflammatory factors. Fluorescence levels of LC3 were detected using immunofluorescence assay. Then, the protein and mRNA expression levels were analyzed using western blot and qRT-PCR. Intracellular adenosine triphosphate (ATP) levels were measured using an ATP kit. Finally, flow cytometry was used to detected apoptosis.

RESULTS: The result showed that XML significantly increase cell viability in H9C2 cells. Compared with XML+LPS (lipopolysaccharide) group, the level of cTNI, CK-MB, interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α was significantly upregulation in LPS+XML+Mdivi-1 or LPS+XML+Atg7 siRNA group. In addition, the release of LC3 was significant decreased. The protein and mRNA expression of PINK1, Parkin, Nix, Beclin-1 was significantly increased, but decreased expression of Mitofusin1, Mitofusin2, Opa1, Drp1, and P62 in LPS+XML+Mdivi-1 or LPS+XML+Atg7 siRNA groups. More importantly, we found that cell apoptosis was induced by Mdivi-1 and Atg7 siRNA.

CONCLUSIONS: The study provided evidence that XML regulated the process of LPS-induced cardiomyocyte injury through mitophagy by the PINK1/Parkin pathway.

Keywords: Lipopolysaccharides, Mitochondrial Degradation, Myocytes, Cardiac, Cell Line, Mitochondria, Periplaneta, Protein Kinases, RNA, Small Interfering, Sepsis, Ubiquitin-Protein Ligases