Change in post-translational modifications of histone H3, heat-shock protein-27 and MAP kinase p38 expression by curcumin in streptozotocin-induced type I diabetic nephropathy

Background and purpose: Curcumin has been used to treat cancer, diabetes and other pathologies. However, little is known regarding its role in altering post-translational modifications of histone H3. A recent report suggests that acute hyperglycaemia induces a global down-regulation of gene expression in human tissues and epigenetic regulation of gene expression could be a novel mechanism underlying the pathological processes of hyperglycaemia. The present study was undertaken to examine changes in histone modification by curcumin treatment which prevents development of type I diabetic nephropathy. Experimental approach: Male Sprague-Dawley rats were rendered diabetic using a single dose of streptozotocin (55 mg kg(-1), i.p.). Diabetic nephropathy was assessed by measurements of blood urea nitrogen, albumin and creatinine levels. Posttranslational modifications of histone H3, heat shock protein-27 (HSP-27) and mitogen-activated protein (MAP) kinase p38 expression were examined by western blotting. Key results: Treatment of diabetic rats with curcumin significantly decreased blood urea nitrogen and creatinine and increased albumin; variables associated with the development of diabetic nephropathy. There were also increased levels of HSP-27 and MAP kinase (p38) in diabetic kidney. However, curcumin treatment prevented this increase in HSP-27 and p38 expression. Moreover, at nuclear level curcumin prevented the decrease in dephosphorylation and increases acetylation of histone H3. Conclusions and implications: Our results suggested that protection against development of diabetic nephropathy by curcumin treatment involved changes in post-translational modifications of histone H3, expression of HSP-27 and MAP kinase p38 in diabetic kidney.