title: Progesterone increases nitric oxide synthesis in human vascular endothelial cells through activation of membrane progesterone receptor-α.
abstract: Progesterone exerts beneficial effects on the human cardiovascular system by inducing rapid increases in nitric oxide (NO) production in vascular endothelial cells, but the receptors mediating these nongenomic progesterone actions remain unclear. Using human umbilical vein endothelial cells (HUVECs) as a model, we show that progesterone binds to plasma membranes of HUVECs with the characteristics of membrane progesterone receptors (mPRs). The selective mPR agonist Org OD 02-0 had high binding affinity for the progesterone receptor on HUVEC membranes, whereas nuclear PR (nPR) agonists R5020 and medroxyprogesterone acetate displayed low binding affinities. Immunocytochemical and Western blot analyses confirmed that mPRs are expressed in HUVECs and are localized on their plasma membranes. NO levels increased rapidly after treatment with 20 nM progesterone, Org OD 02-0, and a progesterone-BSA conjugate but not with R5020, suggesting that this progesterone action is at the cell surface and initiated through mPRs. Progesterone and Org OD 02-0 (20 nM) also significantly increased endothelial nitric oxide synthase (eNOS) activity and eNOS phosphorylation. Knockdown of mPRα expression by treatment with small-interfering RNA (siRNA) blocked the stimulatory effects of 20 nM progesterone on NO production and eNOS phosphorylation, whereas knockdown of nPR was ineffective. Treatment with PI3K/Akt and MAP kinase inhibitors blocked the stimulatory effects of progesterone, Org OD 02-0, and progesterone-BSA on NO production and eNOS phosphorylation and also prevented progesterone- and Org OD 02-0-induced increases in Akt and ERK phosphorylation. The results suggest that progesterone stimulation of NO production in HUVECs is mediated by mPRα and involves signaling through PI3K/Akt and MAP kinase pathways.
authors: Marine Science Institute, University of Texas at Austin, Port Aransas, Texas yfpang@utexas.edu.
authors: Yefei
authors: Y
authors: Pang
authors: Marine Science Institute, University of Texas at Austin, Port Aransas, Texas.
authors: Jing
authors: J
authors: Dong
authors: Marine Science Institute, University of Texas at Austin, Port Aransas, Texas.
authors: Peter
authors: P
authors: Thomas
mesh_terms: D001808:Blood Vessels / Q000378:metabolism; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D009569:Nitric Oxide / Q000096:biosynthesis*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D010920:Placenta / Q000166:cytology / Q000378:metabolism; D011247:Pregnancy; D011374:Progesterone / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011980:Receptors, Progesterone / Q000819:agonists* / Q000378:metabolism
chemical_list: D011980:Receptors, Progesterone; C101118:progesterone receptor A; D009569:Nitric Oxide; D011374:Progesterone; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; D017346:Protein Serine-Threonine Kinases
keywords: human vascular endothelial cells; membrane progesterone receptors; nitric oxide; nitric oxide synthase; rapid progesterone action