Angiotensin II type 1 receptor-mediated increase in cytosolic Ca(2+) and proliferation in mesothelial cells.
We investigated the Ca(2+) signaling pathways of the response to angiotensin II in pleural mesothelial cells and the role of these Ca(2+) signaling pathways in mesothelial cell proliferation. Rat pleural mesothelial cells were maintained in vitro, and the Ca(2+) movement to angiotensin II was evaluated using the fluorescent Ca(2+) indicator fura 2. Furthermore, proliferation of mesothelial cells was assessed using a spectrophotometric 3-(4, 5-dimethylthazol-2-yl)-2,5-diphenyl-2H-tetrasodium bromide (MTT) assay. Angiotensin II (1 pM-100 microM) induced in mesothelial cells a biphasic elevation of intracellular Ca(2+) concentration ([Ca(2+)](i)) that consisted of a transient initial component, followed by a sustained component. Neither removal of extracellular Ca(2+) nor inhibition of Ca(2+) influx by 1 microM nifedipine affected the angiotensin II-induced initial transient elevation of [Ca(2+)](i) in mesothelial cells. Nifedipine did not block angiotensin II-induced sustained elevation of [Ca(2+)](i). Angiotensin II (1 pM-100 microM) had a proliferative effect on mesothelial cells in a dose-dependent manner. Angiotensin II type 1 (AT(1)) receptor antagonist ([Sar(1), Ile(8)]angiotensin II) inhibited both angiotensin II-induced elevation of [Ca(2+)](i) and proliferation of mesothelial cells. Pertussis toxin did not affect angiotensin II-induced responses. These results suggest that angiotensin II-induced responses to mesothelial cells are extremely dependent on the angiotensin AT(1) receptor coupled with pertussis toxin-insensitive G protein.
Kuwahara
M
M
Department of Comparative Pathophysiology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan. akuwam@mail.ecc.u-tokyo.ac.jp
Miyaji
T
T
Tsubone
H
H
D015059:1-Sarcosine-8-Isoleucine Angiotensin II / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D002021:Buffers; D002118:Calcium / Q000378:metabolism* / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D002455:Cell Division / Q000502:physiology; D004396:Coloring Agents; D003470:Culture Media; D003600:Cytosol / Q000378:metabolism*; D005456:Fluorescent Dyes; D016257:Fura-2; D007202:Indicators and Reagents; D009543:Nifedipine / Q000494:pharmacology; D037342:Pertussis Toxin; D010994:Pleura / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin / Q000378:metabolism*; D013778:Tetrazolium Salts; D013844:Thiazoles; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D002021:Buffers; D002121:Calcium Channel Blockers; D004396:Coloring Agents; D003470:Culture Media; D005456:Fluorescent Dyes; D007202:Indicators and Reagents; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin; D013778:Tetrazolium Salts; D013844:Thiazoles; D010566:Virulence Factors, Bordetella; D000804:Angiotensin II; D015059:1-Sarcosine-8-Isoleucine Angiotensin II; D037342:Pertussis Toxin; C022616:thiazolyl blue; D009543:Nifedipine; D002118:Calcium; D016257:Fura-2