Follistatin-like 1 Protects Hyperglycemia-induced Endothelial And Cardiomyoblasts Dysfunction

Objective: Diabetic cardiomyopathy(DCM)is the main causes of the high mortality and mutilation in diabetic patients.Therefore,the American Heart Association(AHA)declared that “Diabetes is cardiovascular disease” in 1999.Endothelial cells are considered as candidates involved in the pathogenesis of diabetic vascular complications.Long-term hyperglycemia is the main risk factors of endothelial and cardiomyocyte dysfunction.It is,therefore,thought that prevention of high glucose-induced endothelial and cardiomyocyte dysfunction may have important implication for pharmacological prevention of DCM.Follistatin-like 1(FSTL1),initially identified as a TGF-β1-inducible gene,is a secreted glycoprotein belonging to a family of matricellular proteins.The purpose of this study is to investigate the potential effect of FSTL1 on hyperglycemia-induced injury in endothelial and cardiomyoblasts.Our study provides novel insights into the cardioprotective role of FSTL1 on diabetic cardiomyopathy.Methods: Human umbilical vein endothelial cells(HUVECs)were maintained in endothelial growth medium-2 containing complete supplement(Hydrocortisone,IGF-1,h EGF,h VEGF,h FGF2,ascorbic acid,GA-1000,heparin and 2% FBS)(normal glucose,NG).In the high glucose(HG)group,cells were incubated with an extra 35 mmol/L of D-glucose for 72 h to mimics hyperglycemia.Rat cardiomyoblast H9c2 cells were cultured in DMEM containing 5.5 or 35 mmol/L of D-glucose as NG or HG group,respectively.Cells were treated with 100 ng/m L of human FSTL1 or transfected with si FSTL1 for “gain-of function” and “loss of function” study.Morphological changes of cells were monitored by inverted microscope.The expression levels of FSTL1,inflammatory cytokinesis,fibrosis,and heart failure factors were detected by q PCR.Angiogenic and migratory potential of endothelial cells were evaluated by tube formation and transwell assay,respectively.Cell proliferation and apoptosis were observed by Ed U and TUNEL,respectively.Results: Hypertrophy of HUVECs was observed and morphology was changed from cobblestone to spindle in HG group.FSTL1 expression was markedly increased by high glucose stimulation in HUVECs by three-fold.Hyperglycemia attenuated angiogenic potential,migration and proliferation in HUVECs.FSTL1 treatment significantly attenuates hyperglycemia-induced endothelial dysfunction,whears knockdown of engenous FSTL1 promotes hyperglycemia-induced endothelial dysfunction,indicating protective role of FSTL1 on diabetic cardiomyopahy.Meanwhile,high glucose stimulation also leads to hypertrophy of H9c2 cells and elevated expression of FSTL1.Marker expression of inflammation(IL-6、IL-17A),fibrosis(FN、α-SMA)and heart failure(BNP、β-MHC)was increased with high glucose treatment,which was downregulated by FSTL1 adiministration.FSTL1 treatment significantly attenuates hyperglycemia-induced cardiac cell death,as evidenced by TUNEL staining of H9c2 cells.Conclusion: In summary,hyperglycemia upregulated FSTL1 expression in HUVECs and H9c2 cells.Additionly,FSTL1 treatment significantly attenuates hyperglycemiainduced endothelial dysfunction.Lastly,FSTL1 has a cardioprotective role on high-glucose-treated cardiomyoblasts,as evidenced by expression of inflammatory,fibrotic and heart failure gene,and cell survival.