ABSTRACT
We examined the effects of overexpressing HSPA12B on angiogenesis and myocardial function by intramyocardial administration of adenovirus encoding HSPA12B (Ad. HSPA12B) in a streptozotocin-induced diabetic rat subjected to myocardial infarction. Rats were divided randomly into six groups: control sham (CS) + Ad.LacZ, control myocardial infarction (CMI) + Ad.LacZ, control MI + Ad.HSPA12B, diabetic sham (DS) + Ad.LacZ, diabetic MI + Ad.LacZ and diabetic MI + Ad.HSPA12B. Following MI or sham surgery, the respective groups received either Ad.LacZ or Ad.HSPA12B via intramyocardial injections. We observed increased capillary and arteriolar density along with reduced fibrosis and preserved heart functions in DMI-AdHSPA12B compared to DMI-AdLacZ group. Western blot analysis demonstrated enhanced HSPA12B, vascular endothelial growth factor (VEGF), thioredoxin-1 (Trx-1) expression along with decreased expression of thioredoxin interacting protein (TXNIP) and A kinase anchoring protein 12 (AKAP12) in the DMI-AdHSPA12B compared to DMI-AdLacZ group. Our findings reveal that HSPA12B overexpression interacts with AKAP12 and downregulate TXNIP in diabetic rats following acute MI.
Subject(s)
A Kinase Anchor Proteins/metabolism , Cell Cycle Proteins/metabolism , Diabetes Mellitus, Experimental/therapy , Genetic Therapy/methods , HSP70 Heat-Shock Proteins/metabolism , Human Umbilical Vein Endothelial Cells/metabolism , Myocardial Infarction/therapy , Ventricular Dysfunction, Left/prevention & control , Ventricular Function, Left , A Kinase Anchor Proteins/genetics , Animals , Carrier Proteins/genetics , Carrier Proteins/metabolism , Cell Cycle Proteins/genetics , Cell Movement , Cells, Cultured , Diabetes Mellitus, Experimental/genetics , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Experimental/physiopathology , Fibrosis , Gene Expression Regulation , HSP70 Heat-Shock Proteins/genetics , Humans , Molecular Docking Simulation , Myocardial Infarction/genetics , Myocardial Infarction/metabolism , Myocardial Infarction/physiopathology , Neovascularization, Physiologic , Protein Binding , RNA Interference , Rats, Sprague-Dawley , Signal Transduction , Time Factors , Transfection , Vascular Endothelial Growth Factor A/genetics , Vascular Endothelial Growth Factor A/metabolism , Ventricular Dysfunction, Left/genetics , Ventricular Dysfunction, Left/metabolism , Ventricular Dysfunction, Left/physiopathologyABSTRACT
BACKGROUND: Statins (HMG-CoA reductase inhibitors), are known to improve cardiac function in diabetes-induced cardiovascular disease. We investigated the mechanism by which statins ameliorate cardiac function after myocardial infarction (MI). Simvastatin (S) increased tube formation and migration of HUVEC in vitro. We examined the role of simvastatin on cardiac function in streptozotocin (STZ) induced diabetic rats subjected to MI. METHODS: Rats were randomly assigned to 1) Control (non-diabetic) Sham (CS); 2) Control (non-diabetic) MI (CMI); 3) Control Statin treated Sham (CSS); 4) Control Statin treated MI (CSMI); 5) Diabetic Sham (DS); 6) Diabetic MI (DMI); 7) Diabetic Statin treated Sham (DSS); 8) Diabetic Statin treated MI (DSMI). Two weeks after STZ/saline injection Simvastatin (1mg/kg.b.wt) was gavaged for 15 days (d). MI was induced 30 d after treatment by permanent LAD ligation. RESULTS: The S treated MI groups exhibited increased arteriolar density (23 ± 0.6 vs. 14.8 ± 0.4 counts/mm(2), DSMI vs. DMI) and reduced fibrosis at 30 d post-MI. VEGF measurement by ELISA after 4d post-MI showed increased expression in DSMI group compared to DMI group. Western blot analysis showed decreased Prolyl-4-Hydroxylase 3 (PHD-3) in DSMI group as compared to DMI group. Echocardiographic analysis 4 weeks after post-MI showed significant improvement in ejection fraction (50.11 ± 1.83 vs. 32.46 ± 2.19%; DSMI vs. DMI) and fractional shortening (26.77 ± 1.12 vs.16.36 ± 1.22%; DSMI vs. DMI) in both statin-treated MI groups regardless of diabetic status. CONCLUSION: These results suggest that statin therapy mitigates impairment of angiogenesis and myocardial dysfunction following MI in the diabetic rat through PHD3 inhibition.
