Low Concentration Of Hydrogen Peroxide Promoted Proliferation Of Cardiomyocytes Through Upregulating WDR26

WDR26 is a gene cloned in laboratory that is up-regulated in ischemic preconditioned rat heart and it was named myocardial ischemic preconditioning up-regulated protein 2(Gen Bank accession number: AY221751). It has an open reading frame of 1497 bp, encoding a polypeptide of 498 amino acids with an N-terminal CTLH domain and 5 C-terminal WD40 repeats.Reactive oxygen species(ROS) are observed increasing in preconditioning and pstconditioning myocardium, but the protect mechanism which ROS involve in remains unkown.In this study, rat ventricular H9c2 cell lines were exposed in low concentration exogenous hydrogen peroxide by different time and different roles of concentration, measures such as cell counting, MTT assay and flow cytometry were taken to observe proliferative effect of low concentration of hydrogen peroxide on cells.When H2O2 of low concentration(12-50μmol/L) stimulated the H9c2 cells, the 570 mn fluorescent absorption rose by MTT analysis, indicating the increase of the cell nmuber,which showed that H2O2 of low concentration could evidently promote the proliferation of H9c2 cells. These results convince that H2O2 of low concentration could induce the malignant transformation of H9c2 cell under certain condition.We next observed the expression pattern of WDR26 in models of H9c2 cells exposed in low concentration exogenous hydrogen peroxide. In this part, WDR26 was chosen to study the dynamic changes of expression by methods of Northern blot and RT-PCR. The reserch showed that: the WDR26 m RNA and protein expression levels were up-regulated after low concentration H2O2 exposure. WDR26 silencing decreased low concentration H2O2-induced proliferation in H9C2 cells. These results indicated that low concentration of hydrogen peroxide promoted proliferation of cardiomyocytes through upregulating WDR26.