Telmisartan-induced eNOS gene expression is partially independent of its PPAR-gamma agonist property.

Purpose: Telmisartan, an angiotensin II receptor blocker (ARB), also acts as an activator of peroxisome proliferator-activated receptor-gamma (PPAR-gamma; PPAR-γ). Several studies have explored the PPAR-γ-endothelial nitric oxide synthase (eNOS) pathway associated with improvement of endothelial function by telmisartan. The ability of telmisartan to induce gene expression and protein level of eNOS and PPARγ in adipocytes was investigated.

Methods: Expression of aP2, PPARγ, eNOS and iNOS genes were measured using the quantitative real-time polymerase chain reaction. The changes, at the protein level, were explored by Western blot, which evaluated the native and phosphorylated eNOS forms, eNOS-Ser(1177) and eNOS-Thr(495).

Results: Adipocytes, exposed to telmisartan, exhibited an increase in PPARγ gene expression but a decrease in protein level. Nonetheless, after the exposure to telmisartan, eNOS-Ser(1177) phosphorylation, associated with eNOS activity increment, reached its highest value while eNOS-Thr(495) phosphorylation, involved in the inhibition of eNOS activity, showed its lowest value.

Conclusion: The results suggest that telmisartan preserves eNOS activity via a mechanism that is partially independent of the PPARγ-eNOS pathway in adipocytes.