1. Helix B Surface Peptide Protects Cardiomyocytes From Hypoxia/Reoxygenation-induced Autophagy Through the PI3K/Akt Pathway
- Author
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Song Huang, Yongluan Lin, Yequn Chen, Zhanbo Liang, Muping Zou, Chang Chen, and Zhuomin Wu
- Subjects
0301 basic medicine ,Autophagy-Related Proteins ,Apoptosis ,Myocardial Reperfusion Injury ,030204 cardiovascular system & hematology ,Cell Line ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Lactate dehydrogenase ,Autophagy ,medicine ,Animals ,Myocytes, Cardiac ,LY294002 ,Viability assay ,Phosphorylation ,Erythropoietin ,Protein kinase B ,PI3K/AKT/mTOR pathway ,Pharmacology ,medicine.disease ,Molecular biology ,Cell Hypoxia ,Peptide Fragments ,Rats ,030104 developmental biology ,chemistry ,Phosphatidylinositol 3-Kinase ,Apoptosis Regulatory Proteins ,Cardiology and Cardiovascular Medicine ,Proto-Oncogene Proteins c-akt ,Reperfusion injury ,Signal Transduction - Abstract
Background Helix B surface peptide (HBSP) is a newly discovered tissue-protective erythropoietin derivative that provides benefits after myocardial ischemia/reperfusion. This study explores the cardioprotective effects of HBSP in myocardial cells in response to hypoxia/reoxygenation injury and its potential mechanism. Methods In this study, rat ventricular (H9c2) cell cultures were established and pretreated with HBSP. H9c2 cardiomyocytes were randomly assigned to the control, H/R, H/R + LY294002 (a PI3K inhibitor), HBSP + H/R, and HBSP + H/R + LY294002 groups. The pretreated cardiomyocytes underwent H/R, and the cardiomyocytes were monitored for viability through a CCK-8 assay, whereas flow cytometry was used to test cell apoptosis. Orgotein Superoxide Dismutase (SOD) and lactate dehydrogenase (LDH) expression were monitored by SOD and LDH kits, respectively. The expression of LC3 autophagosomes was determined by immunocytochemistry. The expression of LC3II/LC3I, p-Mammalian Target of Rapamycin (mTOR) mTOR, mTOR, Beclin 1, p-PI3K, PI3K p-Akt, and Akt was determined by Western blotting. Results HBSP increased cell viability and reduced SOD and LDH production, and it also reduced H/R-induced cell apoptosis. Moreover, the expression of the autophagy-related proteins (LC3II/LC3I) was inhibited by HBSP, whereas the expression of p-PI3K, p-Akt, and p-mTOR was enhanced. However, the PI3K inhibitor (LY294002) notably abolished these effects in H9c2 cells. Conclusions HBSP inhibits excessive autophagy and apoptosis induced by H/R by activating the PI3K/Akt pathway. HBSP may potentially be a therapeutic intervention for myocardial ischemia/reperfusion injury.
- Published
- 2020
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