Vitamin D Ameliorates Angiotensin II-Induced Human Endothelial Progenitor Cell Injury via the PPAR-γ/HO-1 Pathway.

Vitamin D has an important protective effect on chronic inflammatory disease. Angiotensin II (AngII) triggers vascular damage and plays a key role in vascular diseases via several mechanisms, including inflammation. Conversely, vitamin D has been shown to have an important protective effect on chronic inflammation. There is evidence showing that vitamin D can reverse the effects of AngII, but the molecular mechanisms by which this occurs are not known. Our results demonstrate that vitamin D improved the viability, migration ability, and tube formation of AngII-pretreated endothelial progenitor cells (EPCs) and inhibited the apoptosis of EPCs induced by AngII. Vitamin D also reversed reactive oxygen species production, vascular inflammatory cytokine generation, and nuclear factor kappa-B activation in EPCs induced by AngII. Furthermore, EPC pretreatment with GW9662 (the antagonist for PPAR-γ) or siHO-1 decreased the protective effect of vitamin D on AngII-induced EPC injury. Overall, our data indicate that vitamin D ameliorated AngII-induced abnormal EPC injury by decreasing oxidative stress and inflammatory cytokine levels. These findings also suggest that vitamin D protected EPCs from AngII-induced vascular injury via the activation of the PPAR-γ/HO-1 signaling pathway.