TGF-β/Smad3 Stimulates Stem Cell/Developmental Gene Expression and Vascular Smooth Muscle Cell De-Differentiation

In order to determine a mechanism through which TGF-b/Smad3 promote these effects, Affymetrix gene expression arrays were performed on primary rat SMCs infected with Smad3 and stimulated with TGF-b or infected with GFP alone. More than 200 genes were differentially expressed (>2.0 fold change, p<0.05) in TGF-b/Smad3 stimulated SMCs. We then performed GO term enrichment analysis using the DAVID bioinformatics database and found that TGF-b/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. Vascular smooth muscle cells from 3 rats were infected with adenovirus expressing Smad3 and treated with TGF-B for 24 h (TGF-B/Smad3 group). Adenovirus expressing GFP (GFP group) was control. TGF-B/Smad3 treated or control cells were used for RNA extraction and hybridization on Affymetrix microarrays (n=3).