title: Endothelin-1 contributes to increased NFATc3 activation by chronic hypoxia in pulmonary arteries.
abstract: Chronic hypoxia (CH) activates the Ca(2+)-dependent transcription factor nuclear factor of activated T cells isoform c3 (NFATc3) in mouse pulmonary arteries. However, the mechanism of this response has not been explored. Since we have demonstrated that NFATc3 is required for CH-induced pulmonary arterial remodeling, establishing how CH activates NFATc3 is physiologically significant. The goal of this study was to test the hypothesis that endothelin-1 (ET-1) contributes to CH-induced NFATc3 activation. We propose that this mechanism requires increased pulmonary arterial smooth muscle cell (PASMC) intracellular Ca(2+) concentration ([Ca(2+)](i)) and stimulation of RhoA/Rho kinase (ROK), leading to calcineurin activation and actin cytoskeleton polymerization, respectively. We found that: 1) CH increases pulmonary arterial pre-pro-ET-1 mRNA expression and lung RhoA activity; 2) inhibition of ET receptors, calcineurin, L-type Ca(2+) channels, and ROK blunts CH-induced NFATc3 activation in isolated intrapulmonary arteries from NFAT-luciferase reporter mice; and 3) both ET-1-induced NFATc3 activation in isolated mouse pulmonary arteries ex vivo and ET-1-induced NFATc3-green fluorescence protein nuclear import in human PASMC depend on ROK and actin polymerization. This study suggests that CH increases ET-1 expression, thereby elevating PASMC [Ca(2+)](i) and RhoA/ROK activity. As previously demonstrated, elevated [Ca(2+)](i) is required to activate calcineurin, which dephosphorylates NFATc3, allowing its nuclear import. Here, we demonstrate that ROK increases actin polymerization, thus providing structural support for NFATc3 nuclear transport.
authors.affiliation: Department of Cell Biology and Physiology, School of Medicine, University of New Mexico, Albuquerque, NM, 87131, USA.
authors.forename: Sergio
authors.initials: S
authors.lastname: de Frutos
authors.forename: Juan Manuel Ramiro
authors.initials: JM
authors.lastname: Diaz
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Nitta
authors.forename: Mingma L
authors.initials: ML
authors.lastname: Sherpa
authors.forename: Laura V Gonzalez
authors.initials: LV
authors.lastname: Bosc
mesh_terms: D000199:Actins / Q000378:metabolism; D021581:Active Transport, Cell Nucleus; D000818:Animals; D019703:Calcineurin / Q000378:metabolism; D065095:Calcineurin Inhibitors; D020746:Calcium Channels, L-Type / Q000187:drug effects / Q000378:metabolism; D020013:Calcium Signaling; D002478:Cells, Cultured; D002908:Chronic Disease; D003599:Cytoskeleton / Q000378:metabolism; D004195:Disease Models, Animal; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D006801:Humans; D000860:Hypoxia / Q000235:genetics / Q000378:metabolism*; D008297:Male; D049990:Membrane Transport Modulators / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D050778:NFATC Transcription Factors / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011651:Pulmonary Artery / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D017466:Receptors, Endothelin / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013997:Time Factors; D015533:Transcriptional Activation; D014162:Transfection; D015854:Up-Regulation; D020741:rho GTP-Binding Proteins / Q000378:metabolism; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020742:rhoA GTP-Binding Protein
chemical_list: D000199:Actins; D065095:Calcineurin Inhibitors; D020746:Calcium Channels, L-Type; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D049990:Membrane Transport Modulators; D050778:NFATC Transcription Factors; C494009:Nfatc3 protein, mouse; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D017466:Receptors, Endothelin; D011993:Recombinant Fusion Proteins; D054460:rho-Associated Kinases; D019703:Calcineurin; C526380:RhoA protein, mouse; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein