title: Transforming growth factor-beta dynamically regulates vascular smooth muscle differentiation in vivo.
abstract: Variations in the levels of smooth muscle-specific isoforms of contractile proteins have been reported to occur in many different vascular diseases. However, although much work has been done in vitro to investigate the regulation of smooth muscle cell differentiation, the molecular mechanisms which regulate the differentiation of vascular smooth muscle tissue in vivo are unknown. Using quantitative immunofluorescence, we show that in rat arteries levels of smooth muscle differentiation markers correlate with the levels of the cytokine TGF-beta. In young mice with one allele of the TGF-beta1 gene deleted, the levels of both TGF-beta1 and smooth muscle differentiation markers are reduced compared to wild-type controls. This regulation of smooth muscle differentiation by TGF-beta during post-natal development also occurs dynamically in the adult animal. Following various pharmacological or surgical interventions, including treatment of mice with tamoxifen and balloon injury of rat carotid arteries, there is a strong correlation between the changes in the levels of TGF-beta and changes in the levels of smooth muscle differentiation markers (r=0. 9, P<0.0001 for n=26 experiments). We conclude that TGF-beta dynamically regulates smooth muscle differentiation in rodent arteries in vivo.
authors.affiliation: Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK. djg15@mole.bio.cam.ac.uk.
authors.forename: D J
authors.initials: DJ
authors.lastname: Grainger
authors.forename: J C
authors.initials: JC
authors.lastname: Metcalfe
authors.forename: A A
authors.initials: AA
authors.lastname: Grace
authors.forename: D E
authors.initials: DE
authors.lastname: Mosedale
mesh_terms: D000818:Animals; D002339:Carotid Arteries / Q000473:pathology / Q000503:physiopathology; D020212:Carotid Artery Injuries; D002454:Cell Differentiation / Q000502:physiology; D005260:Female; D017353:Gene Deletion; D006579:Heterozygote; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D024510:Muscle Development; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000254:growth & development / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013629:Tamoxifen / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000502:physiology*
chemical_list: D016212:Transforming Growth Factor beta; D013629:Tamoxifen