Vitamin D manipulates miR-181c, miR-20b and miR-15a in human umbilical vein endothelial cells exposed to a diabetic-like environment.

BACKGROUND

High blood and tissue concentrations of glucose and advanced glycation end-products are believed to play an important role in the development of vascular complications in patients with diabetes mellitus (DM) and chronic kidney disease. MicroRNAs (miRNA) are non-coding RNAs that regulate gene expression in a sequence specific manner. MiRNA are involved in various biological processes and become novel biomarkers, modulators and therapeutic targets for diseases such as cancer, atherosclerosis, and DM. Calcitriol (the active form of vitamin D) may inhibit endothelial proliferation, blunt angiogenesis, and be a cardioprotective agent. Calcitriol deficiency is a risk factor for DM and hypertension. The aim of this project was to study the miRNA microarray expression changes in human umbilical vein endothelial cells (HUVEC) treated in a diabetic-like environment with the addition of calcitriol.

METHODS

HUVEC were treated for 24 h with 200 μg/ml human serum albumin (HSA) and 100 mg/dl glucose (control group) or 200 μg/ml AGE-HSA, and 250 mg/dl glucose (diabetic-like environment), and physiological concentrations (10-10 mol/l) of calcitriol. miRNA microarray analysis and real time PCR to validate the miRNA expression profile and mRNA target gene expression were carried out.

RESULTS

Compared to control, 31 mature human miRNA were differentially expressed in the presence of a diabetic-like environment. Addition of physiological concentrations of calcitriol revealed 39 differentially expressed mature human miRNA. MiR-181c, miR-15a, miR-20b, miR-411, miR-659, miR-126 and miR-510 were selected for further analysis because they are known to be modified in DM and in other biological disorders. The predicted targets of these miRNA (such as KLF6, KLF9, KLF10, TXNIP and IL8) correspond to molecular and biological processes such as immune and defense responses, signal transduction and regulation of RNA.

CONCLUSION

This study identified novel miRNA in the field of diabetic vasculopathy and might provide new information about the effect of vitamin D on gene regulation induced by a diabetic-like environment. New gene targets that are part of the molecular mechanism and the therapeutic treatment in diabetic vasculopathy are highlighted.