title: Plasma membrane Ca2+-ATPase regulates Ca2+ signaling and the proliferation of airway smooth muscle cells.
abstract: Plasma membrane Ca2+-ATPase (PMCA) plays an important role in regulating intracellular Ca2+ homeostasis by extruding excessive Ca2+ to extracellular spaces. PMCA has four isoforms and is widely expressed in different tissues and cells including airway smooth muscle cells (ASMCs). In the present study, we investigated the role of PMCA in the maintenance of Ca2+ homeostasis and regulation of ASMCs proliferation. By using Ca2+ fluorescence, we found that inhibition of PMCA with LaCl3 or carboxyeosin (CE) decreased the decay rate of Ca2+ transient induced by bradykinin (BK). No obvious decay was observed when SERCA was inhibited by thapsigargin (TpG). LaCl3 and CE also induced a spontaneous [Ca2+]i increase in the presence of TpG even in Ca2+-free bath solution. Both LaCl3 and CE inhibited UTP-induced Ca2+ oscillations in ASMCs. PCR assay found that PMCA1 and PMCA4 mRNA were expressed in rat ASMCs. The expression of PMCA4 was downregulated in proliferating ASMCs when compared to resting cells. Both the isoform-nonselective PMCA inhibitor caloxin 2a1 and PMCA4-selective inhibitor caloxin 1b1 decreased the decay rate of Ca2+ transient induced by TpG or BK. PMCA inhibitors except caloxin 2a1 promoted ASMCs proliferation. Annexin-V apoptosis assay detected that caloxin 2a1 increased ASMCs apoptosis, suggesting that inhibition of PMCA with different blockers results in different [Ca2+]i and thus different cellular response. Our results provide evidences to support the hypothesis that PMCA is involved in the regulation of Ca2+ homeostasis and ASMCs proliferation. These data suggest that PMCA may be a new target in the treatment of chronic asthma.
authors.affiliation: Department of Respiratory Medicine, Zhongnan Hospital of Wuhan University, Donghu Road 169, Wuhan 430071, PR China.
authors.forename: Yi-fei
authors.initials: YF
authors.lastname: Chen
authors.affiliation: Department of Respiratory Medicine, Zhongnan Hospital of Wuhan University, Donghu Road 169, Wuhan 430071, PR China.
authors.forename: Jie
authors.initials: J
authors.lastname: Cao
authors.affiliation: Department of Respiratory Medicine, Zhongnan Hospital of Wuhan University, Donghu Road 169, Wuhan 430071, PR China.
authors.forename: Jin-nan
authors.initials: JN
authors.lastname: Zhong
authors.affiliation: Department of Respiratory Medicine, Zhongnan Hospital of Wuhan University, Donghu Road 169, Wuhan 430071, PR China.
authors.forename: Xia
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Respiratory Medicine, Zhongnan Hospital of Wuhan University, Donghu Road 169, Wuhan 430071, PR China.
authors.forename: Ming
authors.initials: M
authors.lastname: Cheng
authors.affiliation: Department of Respiratory Medicine, Zhongnan Hospital of Wuhan University, Donghu Road 169, Wuhan 430071, PR China.
authors.forename: Jiong
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Respiratory Medicine, Zhongnan Hospital of Wuhan University, Donghu Road 169, Wuhan 430071, PR China. Electronic address: gaoyadong@gmail.com.
authors.forename: Ya-dong
authors.initials: YD
authors.lastname: Gao
mesh_terms: D000818:Animals; D001980:Bronchi / Q000166:cytology; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D036341:Intercellular Signaling Peptides and Proteins; D007811:Lanthanum / Q000494:pharmacology; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D010455:Peptides / Q000494:pharmacology; D053499:Plasma Membrane Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D017207:Rats, Sprague-Dawley
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D012333:RNA, Messenger; C510327:caloxin 1b1; C423122:caloxin 2A1; C028521:lanthanum chloride; D007811:Lanthanum; D053499:Plasma Membrane Calcium-Transporting ATPases; D002118:Calcium
keywords: Caloxin; Carboxyeosin (PubChem CID: 44119976); LaCl(3) (PubChem CID: 64735); Thapsigargin (PubChem CID: 446378)