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Calcium and growth responses of hyperresponsive airway smooth muscle to different isoforms of platelet-derived growth factor (PDGF).
- Source :
-
Canadian journal of physiology and pharmacology [Can J Physiol Pharmacol] 2000 Nov; Vol. 78 (11), pp. 867-73. - Publication Year :
- 2000
-
Abstract
- Airway smooth muscle (ASM) mass is likely to be an important determinant of airway responsiveness. Highly inbred Fisher rats model innate hyperresponsiveness, and also have more ASM in vivo than control Lewis rats. Platelet derived growth factor (PDGF) is an important endogenous growth factor for ASM, and partially purified PDGF-AB causes enhanced growth of Fisher rat ASM cells, compared to Lewis cells. The aim of the present study was to determine the mitogenic effects of all three recombinant PDGF isoforms on ASM cells, and investigate the mechanisms of enhanced Fisher ASM growth responses. The potential mechanisms assessed include PDGF receptor expression and activation (tyrosine phosphorylation), and intracellular calcium (Ca2+) responses to PDGF isoforms. Fisher ASM cells had a greater mitogenic response to PDGF-AB and -AA, and a greater Ca2+ response to -BB than Lewis ASM cells. A Ca2+ response was not necessary for a mitogenic response, and the effects of PDGF isoforms on Ca2+ were not associated with their effects on growth. Therefore, we suggest that enhanced Fisher mitogenic response to PDGF-AA and -AB is not mediated by differences in Ca2+ signalling. Western analysis of the PDGF receptor indicated a similar expression of beta-PDGF receptor in ASM cells from the two rat strains, but a greater expression of alpha-PDGF receptor in Fisher cells; however, phosphorylation of the PDGF receptor following growth stimulation did not differ between strains. This suggests a role for post-receptor signals, in addition to enhanced receptor expression, in the enhanced growth response of Fisher ASM cells to PDGF-AA and -AB.
- Subjects :
- Animals
Blotting, Western
Cell Division drug effects
Cells, Cultured
Male
Muscle, Smooth physiology
Phosphorylation
Rats
Rats, Inbred F344
Rats, Inbred Lew
Receptors, Platelet-Derived Growth Factor analysis
Receptors, Platelet-Derived Growth Factor metabolism
Trachea physiology
Calcium metabolism
Muscle, Smooth drug effects
Platelet-Derived Growth Factor pharmacology
Trachea drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 0008-4212
- Volume :
- 78
- Issue :
- 11
- Database :
- MEDLINE
- Journal :
- Canadian journal of physiology and pharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 11100934