Activation of transient receptor potential vanilloid 1 decreases endothelial nitric oxide synthase phosphorylation at Thr497 by protein phosphatase 2B‐dependent dephosphorylation of protein kinase C (696.1)

Abstract

We investigated the effects and underlying molecular mechanism of transient receptor potential vanilloid 1 (TRPV1), a calcium‐permeable non‐selective cation channel, on phosphorylation of endothelial nitric oxide synthase (eNOS) at threonine 497 (Thr497) in bovine aortic endothelial cells (BAECs) and in mice. In BAECs, treatment with the TRPV1 ligand evodiamine decreased the phosphorylation of eNOS at Thr497, protein kinase Cα (PKCα at Serine 657, and PKCβ2 at Serine 660. Evodiamine increased protein phosphatase 2B (PP2B) activity and promoted the formation of a PP2B‐PKC complex. Inhibition of TRPV1 activation, removal of extracellular calcium or pharmacological inhibition of PI3K/Akt/CaMKII/AMPK signaling pathway abolished the evodiamine‐induced alterations in phosphorylation of eNOS at Thr497, PKCα, PKCβ2 and PP2B activity, as well as the formation of a PP2B‐PKC complex. Inhibition of PP2B activation partially reduced the evodiamine‐induced NO bioavailability and tube formation in ECs and angiogenesis in mice. Moreover, evodiamine decreased the phosphorylation of eNOS at Thr497, PKCα, and PKCβ2 in apolipoprotein E (ApoE)‐deficient mouse aortas but not TRPV1‐deficient or ApoE/TRPV1 double‐knockout mice. TRPV1 activation in ECs may elicit a calcium‐dependent effect on PP2B‐PKC signaling, which leads to dephosphorylation of eNOS at Thr497 in ECs and in mice.Grant Funding Source: National Science Council, Taiwan