title: Role of NHE1 in calcium signaling and cell proliferation in human CNS pericytes.
abstract: The central nervous system (CNS) pericytes play an important role in brain microcirculation. Na(+)/H(+) exchanger isoform 1 (NHE1) has been suggested to regulate the proliferation of nonvascular cells through the regulation of intracellular pH, Na(+), and cell volume; however, the relationship between NHE1 and intracellular Ca(2+), an essential signal of cell growth, is still not known. The aim of the present study was to elucidate the role of NHE1 in Ca(2+) signaling and the proliferation of human CNS pericytes. The intracellular Ca(2+) concentration was measured by fura 2 in cultured human CNS pericytes. The cells showed spontaneous Ca(2+) oscillation under quasi-physiological ionic conditions. A decrease in extracellular pH or Na(+) evoked a transient Ca(2+) rise followed by Ca(2+) oscillation, whereas an increase in pH or Na(+) did not induce the Ca(2+) responses. The Ca(2+) oscillation was inhibited by an inhibitor of NHE in a dose-dependent manner and by knockdown of NHE1 by using RNA interference. The Ca(2+) oscillation was completely abolished by thapsigargin. The proliferation of pericytes was attenuated by inhibition of NHE1. These results demonstrate that NHE1 regulates Ca(2+) signaling via the modulation of Ca(2+) release from the endoplasmic reticulum, thus contributing to the regulation of proliferation in CNS pericytes.
authors.affiliation: Dept. of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Kuniyuki
authors.initials: K
authors.lastname: Nakamura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kamouchi
authors.forename: Takanari
authors.initials: T
authors.lastname: Kitazono
authors.forename: Junya
authors.initials: J
authors.lastname: Kuroda
authors.forename: Ryu
authors.initials: R
authors.lastname: Matsuo
authors.forename: Noriko
authors.initials: N
authors.lastname: Hagiwara
authors.forename: Eiichi
authors.initials: E
authors.lastname: Ishikawa
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Ooboshi
authors.forename: Setsuro
authors.initials: S
authors.lastname: Ibayashi
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Iida
mesh_terms: D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D001921:Brain / Q000098:blood supply*; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D027682:Cation Transport Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008833:Microcirculation / Q000378:metabolism; D020286:Pericytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D000074082:Sodium-Hydrogen Exchanger 1; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D019284:Thapsigargin / Q000494:pharmacology; D013997:Time Factors
chemical_list: D027682:Cation Transport Proteins; D004791:Enzyme Inhibitors; D034741:RNA, Small Interfering; C490998:SLC9A1 protein, human; D000074082:Sodium-Hydrogen Exchanger 1; D017923:Sodium-Hydrogen Exchangers; C013407:benzamil; C057360:5-(N,N-hexamethylene)amiloride; D019284:Thapsigargin; D000584:Amiloride; D012964:Sodium; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D002118:Calcium