title: Tissue-specific and developmental regulation of transforming growth factor-beta1 expression in fetal lamb ductus arteriosus endothelial cells.
abstract: We previously established that increased hyaluronan synthesis in ductus arteriosus (DA) compared with aorta (Ao) endothelial cells (EC) from early gestation fetal lambs (100-d, term = 145 d) is transforming growth factor-beta (TGF-beta)-dependent. We now address whether this is associated with tissue-specific and developmentally up-regulated expression of TGF-beta1 in the 100-d DA EC. Immunoprecipitation revealed TGF-beta synthesis doubled in DA versus Ao EC from 100-d gestation lambs (p < 0.05). In 138-d DA EC, TGF-beta protein levels were reduced (p < 0.05) and comparable to those in Ao cells. Western immunoblotting with a beta1 isoform-specific antibody confirmed these differences as being related to TGF-beta1. Northern blot analysis demonstrated that TGF-beta1 mRNA levels were slightly but not significantly increased in 100-d DA compared with Ao EC, despite its short half-life in DA (9.5 h) versus Ao EC (20 h). TGF-beta1 mRNA levels were reduced in 138-d DA and Ao EC (p < 0.05), and the mRNA half-life was comparable in DA (9 h) versus Ao (13 h). Nuclear run-on analysis confirmed increased TGF-beta1 mRNA transcription in 100-d DA versus Ao and 138-d DA EC. Thus, up-regulated TGF-beta1 expression in 100-d DA compared with Ao cells is due to increased transcription and translation of a relatively unstable mRNA, and its down-regulation in 138-d DA and Ao EC is related to reduced mRNA transcription and stability, respectively.
authors.affiliation: Research Institute, The Hospital For Sick Children and the Department of Pathology, University of Toronto, Ontario, Canada.
authors.forename: B
authors.initials: B
authors.lastname: Zhou
authors.forename: C
authors.initials: C
authors.lastname: Coulber
authors.forename: M
authors.initials: M
authors.lastname: Rabinovitch
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004373:Ductus Arteriosus / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012756:Sheep; D014018:Tissue Distribution; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D016212:Transforming Growth Factor beta