title: Hydrogen peroxide is a critical regulator of the hypoxia-induced alterations of store-operated Ca2+entry into rat pulmonary arterial smooth muscle cells.
abstract: To investigate the association between store-operated Ca2+entry (SOCE) and reactive oxygen species (ROS) during hypoxia, this study determined the changes of transient receptor potential canonical 1 (TRPC1) and Orai1, two candidate proteins for store-operated Ca2+(SOC) channels and their gate regulator, stromal interaction molecule 1 (STIM1), in a hypoxic environment and their relationship with ROS in pulmonary arterial smooth muscle cells (PASMCs). Exposure to hypoxia caused a transient Ca2+spike and subsequent Ca2+plateau of SOCE to be intensified in PASMCs when TRPC1, STIM1, and Orai1 were upregulated. SOCE in cells transfected with specific short hairpin RNA (shRNA) constructs was almost completely eliminated by the knockdown of TRPC1, STIM1, or Orai1 alone and was no longer affected by hypoxia exposure. Hypoxia-induced SOCE enhancement was further strengthened by PEG-SOD but was attenuated by PEG-catalase, with correlated changes to intracellular hydrogen peroxide (H2O2) levels and protein levels of TRPC1, STIM1, and Orai1. Exogenous H2O2could mimic alterations of the interactions of STIM1 with TRPC1 and Orai1 in hypoxic cells. These findings suggest that TRPC1, STIM1, and Orai1 are essential for the initiation of SOCE in PASMCs. Hypoxia-induced ROS promoted the expression and interaction of the SOC channel molecules and their gate regulator via their converted product, H2O2.
authors.affiliation: Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Tao-Xiang
authors.initials: TX
authors.lastname: Chen
authors.affiliation: Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Xiao-Ya
authors.initials: XY
authors.lastname: Xu
authors.affiliation: Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Fang-Yu
authors.initials: FY
authors.lastname: Zhao
authors.affiliation: Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Yi-Mei
authors.initials: YM
authors.lastname: Gao
authors.affiliation: Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, China.
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Yan
authors.affiliation: Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei, China wanyu@whu.edu.cn.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wan
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D002478:Cells, Cultured; D055785:Gene Knockdown Techniques; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D000860:Hypoxia / Q000235:genetics / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D000071740:ORAI1 Protein / Q000235:genetics / Q000378:metabolism; D011092:Polyethylene Glycols / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D011651:Pulmonary Artery / Q000473:pathology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D000071737:Stromal Interaction Molecule 1 / Q000235:genetics / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D015220:Calcium Channels; D000071740:ORAI1 Protein; C532493:Orai1 protein, rat; D012333:RNA, Messenger; C518857:Stim1 protein, rat; D000071737:Stromal Interaction Molecule 1; D050052:TRPC Cation Channels; C070295:catalase-polyethylene glycol; C096351:transient receptor potential cation channel, subfamily C, member 1; D011092:Polyethylene Glycols; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; C063471:polyethylene glycol-superoxide dismutase; D002118:Calcium
keywords: hypoxia; reactive oxygen species; store-operated Ca2+ entry