Responses of pertussis toxin-treated microvascular endothelial cells to transforming growth factor beta 1. No evidence for pertussis-sensitive G-protein involvement in TGF-beta signal transduction.
Responses of bovine adrenal capillary endothelial cells (BACE) on treatment with transforming growth factor beta 1 (TGF-beta 1) have been characterized and tested for sensitivity to inactivation of pertussis toxin-sensitive G-proteins. TGF-beta 1 elicited growth inhibition, monolayer remodeling, elevation of steady state mRNA levels for collagen type 1 (alpha 1(1) and alpha 2(1)) and TGF-beta 1, and inhibition of p34cdc2 histone H1 kinase activity in BACE cells. Pertussis toxin treatment enhanced both inhibition of BACE cell [3H]methylthymidine uptake and remodeling of BACE monolayers by TGF-beta 1. These findings contrast with studies of mink lung epithelial cells, in which TGF-beta 1 growth inhibition has been shown to be pertussis-sensitive. Further investigation revealed that pertussis toxin treatment of BACE cells had no effect on TGF-beta 1-stimulated elevation of steady state mRNA levels for collagen type 1 (alpha 1(1) or alpha 2(1)) or for TGF-beta 1. Analysis of p34cdc2 activity in BACE cells revealed potent inhibition of p34cdc2 histone H1 kinase activity by TGF-beta 1. Pertussis toxin treatment also abolished the increase in p34cdc2 activity, however, precluding the determination of the pertussis toxin sensitivity of this response to TGF-beta 1. Consistent with suppression of p34cdc2 activation, pertussis toxin also caused substantial inhibition of mitogen-stimulated BACE cell [3H]methylthymidine uptake. It is concluded that TGF-beta 1 signal transduction in this cell type does not involve G-proteins of the pertussis toxin-sensitive class and that, in view of its potent effects on DNA synthesis and p34cdc2 activation, the use of pertussis toxin to determine G-protein involvement in cytokine signalling pathways should be approached with caution.
McCarthy
S A
SA
Imperial Cancer Research Fund Laboratories, University of Oxford, John Radcliffe Hospital, United Kingdom.
Bicknell
R
R
D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003094:Collagen / Q000235:genetics; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D037342:Pertussis Toxin; D011233:Precipitin Tests; D006656:Protamine Kinase / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction; D013936:Thymidine / Q000031:analogs & derivatives / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000494:pharmacology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D010566:Virulence Factors, Bordetella; D003094:Collagen; C012439:methylthymidine; D037342:Pertussis Toxin; D006656:Protamine Kinase; D016203:CDC2 Protein Kinase; D019204:GTP-Binding Proteins; D013936:Thymidine