title: Transforming growth factor beta 1 expression and effect in aortic smooth muscle cells from spontaneously hypertensive rats.
abstract: Previous studies demonstrated that in addition to an increased response to growth factors, cultured vascular smooth muscle cells derived from spontaneously hypertensive rats (SHRs) grow to a greater density than cells from normotensive Wistar-Kyoto (WKY) rats. Transforming growth factor beta 1 (TGF-beta 1) has a bimodal effect on vascular smooth muscle cell growth, depending on cell density. The present study investigated the relation between cell density and expression of the proto-oncogene c-fos and TGF-beta 1 in cells from WKY rats and SHRs. The results demonstrate an increased accumulation of c-fos mRNA in calf serum-stimulated SHR cells but only at a high cell density. The expression of TGF-beta 1 mRNA was enhanced in growing SHR cells at every density studied as early as 24 hours after inoculation, with a further increase at later times. The effect of exogenous TGF-beta 1 on new DNA synthesis was evaluated by [3H]thymidine incorporation. At a low cell density, TGF-beta 1 had no effect on DNA synthesis in either WKY or SHR vascular smooth muscle cells. At a high cell density, there was a significant increase of DNA synthesis in response to TGF-beta 1 in SHR cells without any effect in WKY cells. In conclusion, contact inhibition of vascular smooth muscle cells from SHRs at a higher cell density is accompanied by an earlier expression of the marker gene c-fos and preceded by an exaggerated expression of TGF-beta 1.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Clinical Research Institute of Montreal, Quebec, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Hamet
authors.forename: V
authors.initials: V
authors.lastname: Hadrava
authors.forename: U
authors.initials: U
authors.lastname: Kruppa
authors.forename: J
authors.initials: J
authors.lastname: Tremblay
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology / Q000378:metabolism*; D002452:Cell Count; D002455:Cell Division; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D016193:G1 Phase; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D013936:Thymidine / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D004247:DNA; D013936:Thymidine