TGF-β/Smad3 stimulates stem cell/developmental gene expression and vascular smooth muscle cell de-differentiation.
Atherosclerotic-associated diseases are the leading cause of death in the United States. Despite recent progress, interventional treatments for atherosclerosis can be complicated by restenosis resulting from neo-intimal hyperplasia. We have previously demonstrated that TGF-β and its downstream signaling protein Smad3 ∶ 1) are up-regulated following vascular injury, 2) together drive smooth muscle cell (SMC) proliferation and migration and 3) enhance the development of intimal hyperplasia. In order to determine a mechanism through which TGF-β/Smad3 promote these effects, Affymetrix gene expression arrays were performed on primary rat SMCs infected with Smad3 and stimulated with TGF-β or infected with GFP alone. More than 200 genes were differentially expressed (>2.0 fold change, p<0.05) in TGF-β/Smad3 stimulated SMCs. We then performed GO term enrichment analysis using the DAVID bioinformatics database and found that TGF-β/Smad3 activated the expression of multiple genes related to either development or cell differentiation, several of which have been shown to be associated with multipotent stem or progenitor cells. Quantitative real-time PCR confirmed up-regulation of several developmental genes including FGF1, NGF, and Wnt11 (by 2.5, 6 and 7 fold, respectively) as well as stem/progenitor cell associated genes CD34 and CXCR4 (by 10 and 45 fold, respectively). In addition, up-regulation of these factors at protein levels were also confirmed by Western blotting, or by immunocytochemistry (performed for CXCR4 and NGF). Finally, TGF-β/Smad3 down regulated transcription of SMC contractile genes as well as protein production of smooth muscle alpha actin, calponin, and smooth muscle myosin heavy chain. These combined results suggest that TGF-β/Smad3 stimulation drives SMCs to a phenotypically altered state of de-differentiation through the up-regulation of developmental related genes.
Department of Surgery, University of Wisconsin Hospital and Clinics, Madison, Wisconsin, United States of America.
Xudong
X
Shi
Department of Surgery, University of Wisconsin Hospital and Clinics, Madison, Wisconsin, United States of America.
Daniel
D
DiRenzo
Department of Surgery, University of Wisconsin Hospital and Clinics, Madison, Wisconsin, United States of America.
Lian-Wang
LW
Guo
Department of Surgery, University of Wisconsin Hospital and Clinics, Madison, Wisconsin, United States of America.
Sarah R
SR
Franco
Department of Surgery, University of Wisconsin Hospital and Clinics, Madison, Wisconsin, United States of America.
Bowen
B
Wang
Department of Surgery, University of Wisconsin Hospital and Clinics, Madison, Wisconsin, United States of America.
Stephen
S
Seedial
Department of Surgery, University of Wisconsin Hospital and Clinics, Madison, Wisconsin, United States of America.
K Craig
KC
Kent
D000818:Animals; D001011:Aorta; D054337:Cell Dedifferentiation / Q000235:genetics; D002455:Cell Division / Q000235:genetics; D002478:Cells, Cultured; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D006965:Hyperplasia; D008297:Male; D009124:Muscle Proteins / Q000096:biosynthesis* / Q000235:genetics; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D051900:Smad3 Protein; D014158:Transcription, Genetic / Q000235:genetics; D059467:Transcriptome; D014161:Transduction, Genetic; D053773:Transforming Growth Factor beta1; D017539:Tunica Intima / Q000473:pathology
D009124:Muscle Proteins; D011993:Recombinant Fusion Proteins; D051900:Smad3 Protein; C497787:Smad3 protein, rat; C508962:Tgfb1 protein, rat; D053773:Transforming Growth Factor beta1