G protein-coupled estrogen receptor 1 mediates relaxation of coronary arteries via cAMP/PKA-dependent activation of MLCP

Abstract

Yu X, Li F, Klussmann E, Stallone JN, Han G. G proteincoupled estrogen receptor 1 mediates relaxation of coronary arteries via cAMP/PKA-dependent activation of MLCP. Am J Physiol Endocrinol Metab 307: E398 -E407, 2014. First published July 8, 2014 doi:10.1152/ajpendo.00534.2013.-Activation of GPER exerts a protective effect in hypertension and ischemia-reperfusion models and relaxes arteries in vitro. However, our understanding of the mechanisms of GPER-mediated vascular regulation is far from complete. In the current study, we tested the hypothesis that GPER-induced relaxation of porcine coronary arteries is mediated via cAMP/PKA signaling. Our findings revealed that vascular relaxation to the selective GPER agonist G-1 (0.3-3 M) was associated with increased cAMP production in a concentration-dependent manner. Furthermore, inhibition of adenylyl cyclase (AC) with SQ-22536 (100 M) or of PKA activity with either Rp-8-CPT-cAMPS (5 M) or PKI (5 M) attenuated G-1-induced relaxation of coronary arteries preconstricted with PGF2␣ (1 M). G-1 also increased PKA activity in cultured coronary artery smooth muscle cells (SMCs). To determine downstream signals of the cAMP/PKA cascade, we measured RhoA activity in cultured human and porcine coronary SMCs and myosin-light chain phosphatase (MLCP) activity in these artery rings by immunoblot analysis of phosphorylation of myosin-targeting subunit protein-1 (p-MYPT-1; the MLCP regulatory subunit). G-1 decreased PGF2␣-induced p-MYPT-1, whereas Rp-8-CPT-cAMPS prevented this inhibitory effect of G-1. Similarly, G-1 inhibited PGF2␣-induced phosphorylation of MLC in coronary SMCs, and this inhibitory effect was also reversed by Rp-8-CPT-cAMPS. RhoA activity was downregulated by G-1, whereas G36 (GPER antagonist) restored RhoA activity. Finally, FMP-API-1 (100 M), an inhibitor of the interaction between PKA and A-kinase anchoring proteins (AKAPs), attenuated the effect of G-1 on coronary artery relaxation and p-MYPT-1. These findings demonstrate that localized cAMP/PKA signaling is involved in GPER-mediated coronary vasodilation by activating MLCP via inhibition of RhoA pathway.

Activation of G protein-coupled estrogen receptor 1 induces coronary artery relaxation via Epac/Rap1-mediated inhibition of RhoA/Rho kinase pathway in parallel with PKA

“…The mechanism of GPER-mediated vascular relaxation is, however, far from clear. As a typical G-protein-coupled receptor, GPER has been reported to interact with Gs, and thereby activate adenylyl cyclase and increase cAMP production in GPER-transfected HEK293 cell plasma membrane extracts and human CASMCs [9, 10]. Our recent work has demonstrated that cAMP/PKA signaling is involved in GPER-mediated relaxation.…”

“…Our recent work has demonstrated that cAMP/PKA signaling is involved in GPER-mediated relaxation. In human and porcine CASMCs, GPER activation increased cAMP production and activated PKA activity, which in turn, phosphorylated RhoA and thus, inhibited RhoA activity, resulting in activation of the myosin light chain (MLC) phosphatase (MLCP) and dephosphorylation of MLC [10]. …”

Advanced Glycation End Products Impair Ca2+ Mobilization and Sensitization in Colonic Smooth Muscle Cells via the CAMP/PKA Pathway

“…Previous studies have demonstrated that the cAMP/PKA pathway is activated by AGEs in diabetes [36]. Moreover, the cAMP/PKA pathway is widely recognized to regulate aortic SM contraction [37,38]. In gastric SMCs and intact aorta, PKA-mediated phosphorylation of IP 3 R3 decreases the number of binding sites for IP 3 on IP 3 R3 and thus attenuates IP 3 R3-mediated Ca 2+ release [29].…”

Pharmacological Interference With Protein-protein Interactions of Akinase Anchoring Proteins as a Strategy for the Treatment of Disease

“…In hypertension and ischemia--reperfusion models activation of GPER is protective as it relaxes arteries. Inhibition of AKAP--PKA interactions with FMP--API--1 attenuated the effect of GPER activation on coronary artery relaxation by a mechanism involving activation of myosin light chain phosphatase and inhibition of a RhoA pathway [247].…”

“…This conservation also hampers the development of peptidomimetics and small molecules for inhibition of specific AKAP--PKA interactions. The first peptidomimetics [6,153,220] and a first small molecule, FMP--API--1, for the non--selective disruption of AKAP--PKA interactions are available [36,247]. There are hints that allosteric sites such as the RI Specifier Region (RISR) in D--AKAPs [6] and a region C--terminally from the D/D domain of RII [36] are involved in AKAP--PKA interactions.…”