|
|
||||||||
Department of Pharmacology, College of Medicine, University of Illinois, Chicago, Illinois 60612-7343
We studied dynamics of cell surface expression of proteolytically activated thrombin receptor (PAR-1) in human pulmonary artery endothelial cells (HPAEC). PAR-1 activation was measured by changes in cytosolic calcium concentration ([Ca2+]i) and HPAEC retraction response (determined by real-time transendothelial monolayer electrical resistance). [Ca2+]i increase in response to thrombin was abolished by preexposure to 25 nM thrombin for >60 min, indicating PAR-1 desensitization, but preexposure to 25 nM thrombin for only 30 min or to 10 nM thrombin for up to 2 h did not desensitize PAR-1. Exposure to 10 or 25 nM thrombin decreased monolayer electrical resistance 40-60%. Cells preexposed to 10 nM thrombin, but not those preexposed to 25 nM thrombin, remained responsive to thrombin 3 h later. Loss of cell retractility was coupled to decreased cell surface PAR-1 expression as determined by immunofluorescence. Cell surface PAR-1 disappeared upon short-term (30 min) thrombin exposure but reappeared within 90 min after incubation in thrombin-free medium. Exposure to 25 nM thrombin for >60 min prevented rapid cycloheximide-insensitive PAR-1 reappearance. Cycloheximide-sensitive recovery of cell surface PAR-1 expression required 18 h. Therefore, both duration and concentration of thrombin exposure regulate the time course of recovery of HPAEC surface PAR-1 expression. The results support the hypothesis that initial recovery of PAR-1 surface expression in endothelial cells results from a rapidly mobilizable PAR-1 pool, whereas delayed recovery results from de novo PAR-1 synthesis. We conclude that thrombin itself regulates endothelial cell surface PAR-1 expression and that decreased surface expression interferes with thrombin-induced endothelial cell activation responses.
proteolytically activated thrombin receptor; human pulmonary artery endothelial cells; endothelial monolayer resistance; cytosolic calcium concentration
This article has been cited by other articles:
![]() |
D. Mehta and A. B. Malik Signaling Mechanisms Regulating Endothelial Permeability Physiol Rev, January 1, 2006; 86(1): 279 - 367. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. C. Paria, S. M. Vogel, G. U. Ahmmed, S. Alamgir, J. Shroff, A. B. Malik, and C. Tiruppathi Tumor necrosis factor-{alpha}-induced TRPC1 expression amplifies store-operated Ca2+ influx and endothelial permeability Am J Physiol Lung Cell Mol Physiol, December 1, 2004; 287(6): L1303 - L1313. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Tiruppathi, M. Freichel, S. M. Vogel, B. C. Paria, D. Mehta, V. Flockerzi, and A. B. Malik Impairment of Store-Operated Ca2+ Entry in TRPC4-/- Mice Interferes With Increase in Lung Microvascular Permeability Circ. Res., July 12, 2002; 91(1): 70 - 76. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Tiruppathi, T. Naqvi, R. Sandoval, D. Mehta, and A. B. Malik Synergistic effects of tumor necrosis factor-{alpha} and thrombin in increasing endothelial permeability Am J Physiol Lung Cell Mol Physiol, October 1, 2001; 281(4): L958 - L968. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. R. Macfarlane, M. J. Seatter, T. Kanke, G. D. Hunter, and R. Plevin Proteinase-Activated Receptors Pharmacol. Rev., June 1, 2001; 53(2): 245 - 282. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Sandoval, A. B. Malik, T. Naqvi, D. Mehta, and C. Tiruppathi Requirement for Ca2+ signaling in the mechanism of thrombin-induced increase in endothelial permeability Am J Physiol Lung Cell Mol Physiol, February 1, 2001; 280(2): L239 - L247. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. M. VOGEL, X. GAO, D. MEHTA, R. D. YE, T. A. JOHN, P. ANDRADE-GORDON, C. TIRUPPATHI, and A. B. MALIK Abrogation of thrombin-induced increase in pulmonary microvascular permeability in PAR-1 knockout mice Physiol Genomics, December 18, 2000; 4(2): 137 - 145. [Abstract] [Full Text] [PDF] |
||||
![]() |
X. Gao, P. Kouklis, N. Xu, R. D. Minshall, R. Sandoval, S. M. Vogel, and A. B. Malik Reversibility of increased microvessel permeability in response to VE-cadherin disassembly Am J Physiol Lung Cell Mol Physiol, December 1, 2000; 279(6): L1218 - L1225. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |