title: G protein-coupled estrogen receptor 1 mediates relaxation of coronary arteries via cAMP/PKA-dependent activation of MLCP.
abstract: 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 μM) was associated with increased cAMP production in a concentration-dependent manner. Furthermore, inhibition of adenylyl cyclase (AC) with SQ-22536 (100 μM) or of PKA activity with either Rp-8-CPT-cAMPS (5 μM) or PKI (5 μM) attenuated G-1-induced relaxation of coronary arteries preconstricted with PGF2α (1 μM). 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 PGF2α-induced p-MYPT-1, whereas Rp-8-CPT-cAMPS prevented this inhibitory effect of G-1. Similarly, G-1 inhibited PGF2α-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 μM), 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.
authors.affiliation: Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, Texas;
authors.forename: Xuan
authors.initials: X
authors.lastname: Yu
authors.affiliation: Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, Texas; College of Life Science, Henan Normal University, Xinxiang, Henan Province, China; and.
authors.forename: Fen
authors.initials: F
authors.lastname: Li
authors.affiliation: Anchored Signaling, Max-Delbrück-Centrum für Molekulare Medizin Berlin-Buch, Berlin, Germany.
authors.forename: Enno
authors.initials: E
authors.lastname: Klussmann
authors.affiliation: Women's Health Division, Michael E. DeBakey Institute, and Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, Texas;
authors.forename: John N
authors.initials: JN
authors.lastname: Stallone
authors.affiliation: Women's Health Division, Michael E. DeBakey Institute, and Department of Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A & M University, College Station, Texas; ghan@cvm.tamu.edu.
authors.forename: Guichun
authors.initials: G
authors.lastname: Han
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000187:drug effects / Q000502:physiology*; D000242:Cyclic AMP / Q000378:metabolism / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D043263:Myosin-Light-Chain Phosphatase / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000502:physiology*; D043562:Receptors, G-Protein-Coupled / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects; D013552:Swine; D014664:Vasodilation / Q000187:drug effects
chemical_list: C109584:GPER1 protein, human; D011960:Receptors, Estrogen; D043562:Receptors, G-Protein-Coupled; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D043263:Myosin-Light-Chain Phosphatase
keywords: G protein-coupled estrogen receptor 1; coronary artery; cyclic adenosine 5′-phosphate; myosin light-chain phosphatase; protein kinase A