Tali Zitman-Gal, Janice Green, Metsada Pasmanik-Chor, Varda Oron-Karni, Jacques Bernheim and Sydney Benchetrit
Background: Diabetes mellitus (DM) is one of the leading causes of chronic vascular disease, which can accelerate the development of cardiovascular and renal disorders. Vascular smooth muscle cells (VSMC) are involved in the occurrence of vascular atherosclerosis and arteriosclerosis. Calcitriol might inhibit endothelial proliferation, blunt angiogenesis, and serve as a cardioprotective agent. We evaluated the impact of a diabetic-like environment and calcitriol on VSMC gene and protein expression. Methods: VSMC were treated for 24 hours using 200 μg/ml AGE-HSA, 250 mg/dl glucose and 10-9 or 10-10 mol/l calcitriol. Microarray gene chip analysis, real time PCR, western blot and ELISA techniques were used to determine gene and protein expression. Results: A total of 2,693 genes were differentially expressed in a diabetic-like environment compared to control, with 1796 up-regulated and 897 down-regulated. These genes are responsible for functions involved in the regulation of metabolic processes, apoptosis and cell adhesion. Addition of calcitriol at physiological concentrations (10-10 mol/l) revealed 1,157 differentially expressed genes, with 673 up-regulated and 484 down-regulated. These genes significantly enriched functions such as regulation of small GTPase and RAS protein signal transduction, cell growth and extracellular matrix part. TXNIP, OPG, RANKL, KLF4, RANK and NFκB p50/p65 mRNA and protein expressions were further investigated. Conclusion: High throughput approach might lead to a better understanding of the pathways involved in the biological adaptation of VSMC exposed to diabetic-like conditions and eventually the possible beneficial effects of calcitriol treatment, which might delay the development of DM-related vascular complications.