title: Response gene to complement 32, a novel regulator for transforming growth factor-beta-induced smooth muscle differentiation of neural crest cells.
abstract: We previously developed a robust in vitro model system for vascular smooth muscle cell (VSMC) differentiation from neural crest cell line Monc-1 upon transforming growth factor-beta (TGF-beta) induction. Further studies demonstrated that both Smad and RhoA signaling are critical for TGF-beta-induced VSMC development. To identify downstream targets, we performed Affymetrix cDNA array analysis of Monc-1 cells and identified a gene named response gene to complement 32 (RGC-32) to be important for the VSMC differentiation. RGC-32 expression was increased 5-fold after 2 h and 50-fold after 24 h of TGF-beta induction. Knockdown of RGC-32 expression in Monc-1 cells by small interfering RNA significantly inhibited the expression of multiple smooth muscle marker genes, including SM alpha-actin (alpha-SMA), SM22alpha, and calponin. Of importance, the inhibition of RGC-32 expression correlated with the reduction of alpha-SMA while not inhibiting smooth muscle-unrelated c-fos gene expression, suggesting that RGC-32 is an important protein factor for VSMC differentiation from neural crest cells. Moreover, RGC-32 overexpression significantly enhanced TGF-beta-induced alpha-SMA, SM22alpha, and SM myosin heavy chain promoter activities in both Monc-1 and C3H10T1/2 cells. The induction of VSMC gene promoters by RGC-32 appears to be CArG-dependent. These data suggest that RGC-32 controls VSMC differentiation by regulating marker gene transcription in a CArG-dependent manner. Further studies revealed that both Smad and RhoA signaling are important for RGC-32 activation.
authors.affiliation: Department of Pediatrics, Georgetown University Medical Center, Washington, DC 20057, USA.
authors.forename: Fengmin
authors.initials: F
authors.lastname: Li
authors.forename: Zaiming
authors.initials: Z
authors.lastname: Luo
authors.forename: Wenyan
authors.initials: W
authors.lastname: Huang
authors.forename: Quansheng
authors.initials: Q
authors.lastname: Lu
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Wilcox
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Jose
authors.forename: Shiyou
authors.initials: S
authors.lastname: Chen
mesh_terms: D000818:Animals; D000943:Antigens, Differentiation / Q000096:biosynthesis* / Q000235:genetics; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D051379:Mice; D008954:Models, Biological; D009124:Muscle Proteins / Q000096:biosynthesis* / Q000235:genetics; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D009432:Neural Crest / Q000166:cytology / Q000378:metabolism*; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D000943:Antigens, Differentiation; D009124:Muscle Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; C520017:Rgc-32 protein, mouse; D016212:Transforming Growth Factor beta