title: Wilms' tumor 1-associating protein regulates the proliferation of vascular smooth muscle cells.
abstract: Smooth muscle cells (SMCs) are called on to proliferate during vascular restructuring but must return to a nonproliferative state if remodeling is to appropriately terminate. To identify mediators of the reacquisition of replicative quiescence, we undertook gene expression screening in a uniquely plastic human SMC line. As proliferating SMCs shifted to a contractile and nonproliferative state, expression of TIMP-3, Axl, and KIAA0098 decreased whereas expression of complement C1s, cathepsin B, cellular repressor of E1A-activated genes increased. Wilms' tumor 1-associating protein (WTAP), a nuclear constituent of unknown function, was also upregulated as SMCs became nonproliferative. Furthermore, WTAP in the intima of injured arteries was substantially upregulated in the late stages of repair. Introduction of WTAP complementary DNA into human SMCs inhibited their proliferation, with a corresponding decrease in DNA synthesis and an increase in apoptosis. Knocking down endogenous WTAP increased SMC proliferation, because of increased DNA synthesis and G(1)/S phase transition, together with reduced apoptosis. WTAP was found to associate with the Wilms' tumor-1 protein in human SMCs and WTAP overexpression inhibited the binding of WT1 to an oligonucleotide containing a consensus WT1 binding site, whereas WTAP knockdown accentuated this interaction. Expression of the WT1 target genes, amphiregulin and Bcl-2, was suppressed in WTAP-overexpressing SMCs and increased in WTAP-deficient SMCs. Moreover, exogenous amphiregulin rescued the antiproliferative effect of WTAP. These findings identify WTAP as a novel regulator of the cell cycle and cell survival and implicate a WTAP-WT1 axis as a novel pathway for controlling vascular SMC phenotype.
authors.affiliation: Robarts Research Institute, London, Ontario, Canada.
authors.forename: Theodore W
authors.initials: TW
authors.lastname: Small
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Bolender
authors.forename: Clara
authors.initials: C
authors.lastname: Bueno
authors.forename: Caroline
authors.initials: C
authors.lastname: O'Neil
authors.forename: Zengxuan
authors.initials: Z
authors.lastname: Nong
authors.forename: Walter
authors.initials: W
authors.lastname: Rushlow
authors.forename: Nagalingham
authors.initials: N
authors.lastname: Rajakumar
authors.forename: Christopher
authors.initials: C
authors.lastname: Kandel
authors.forename: Jennifer
authors.initials: J
authors.lastname: Strong
authors.forename: Joaquin
authors.initials: J
authors.lastname: Madrenas
authors.forename: J Geoffrey
authors.initials: JG
authors.lastname: Pickering
mesh_terms: D066258:Amphiregulin; D000800:Angioplasty, Balloon / Q000009:adverse effects; D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology; D017209:Apoptosis / Q000502:physiology; D020212:Carotid Artery Injuries / Q000378:metabolism / Q000473:pathology; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D018797:Cell Cycle Proteins; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D066255:EGF Family of Proteins; D020868:Gene Silencing; D006023:Glycoproteins / Q000494:pharmacology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism*; D000072260:RNA Splicing Factors; D051381:Rats; D011921:Rats, Inbred WKY; D017207:Rats, Sprague-Dawley; D014158:Transcription, Genetic / Q000187:drug effects / Q000502:physiology; D015854:Up-Regulation / Q000502:physiology; D025721:WT1 Proteins / Q000378:metabolism
chemical_list: C587848:AREG protein, human; D066258:Amphiregulin; C587850:Areg protein, rat; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D066255:EGF Family of Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D000072260:RNA Splicing Factors; D025721:WT1 Proteins; C419554:WTAP protein, human