Effect and molecular mechanism of serum exosomes of diabetic mice on regulating H9C2 myocardial cell injury / 解放军医学杂志

ABSTRACT

[Abstract] Objective To investigate the effect of exosome in cultured in vitro H9C2 myocardial cells injury of diabetic mice and its mechanism. Methods The mouse model of diabetic myocardial injury was established by using db/db mice (n=10) and their mate mice db/+ (n=5). Serum exosomes were isolated and quantitated using the exosome isolation reagent and EXOCET Quantitation kit. The serum exosomes were labeled with PKH26 (red fluorescent cell linker) to detect the endocytosis in H9C2 cells. The expressions of exocrine associated protein and inflammatory cytokines in H9C2 cells with or without exosome stimulation were detected by Western blotting. TUNEL was used to detect apoptosis. A neutralizing antibody of Rab1a was used for blocking experiment. Results Db/db mice produced more exosomes than db/+ mice (30.95×109/ml vs. 10.45×109/ml, P<0.01). Moreover, H9C2 cells cultured in vitro could swallow more serum-exosomes derived from db/db mice. Meanwhile, serum exosome from db/ db mice, as used to interfere H9C2 cells, significantly increased the expression of inflammatory cytokines, such as 6.2 folds to IL-6 and 2.6 folds to IL-1β (P<0.01). Furthermore, the apoptosis in H9C2 cells increased compared to those from db/+ mice. Mechanism studies announced that the increased expression of Rab1a in exosomes-derived from db/db mice, and blocking the expression of Rab1a in exocrine of db/db mice with Rab1a neutralizing antibody could significantly inhibit the endocytosis and apoptosis of H9C2 cells. Conclusions Serum exosomes isolated from db/db mice may trigger inflammation and apoptosis of cardiomyocytes cultured in vitro, which may be involved in the evolution of diabetic myocardial injury. Inhibition of exosome secretion or intervention of its regulatory molecules may become a new research target for the treatment of diabetic myocardial injury.