Transforming growth factor beta up-regulates cysteine-rich protein 2 in vascular smooth muscle cells via activating transcription factor 2.
CRP2 (cysteine-rich protein) is a vascular smooth muscle cell (VSMC)-expressed LIM-only protein. CRP2 associates with the actin cytoskeleton and interacts with transcription factors in the nucleus to mediate smooth muscle cell gene expression. Using Csrp2 (gene symbol of the mouse CRP2 gene)-deficient mice, we previously demonstrated that an absence of CRP2 enhances VSMC migration and increases neointima formation following arterial injury. Despite its importance in vascular injury, the molecular mechanisms controlling CRP2 expression in VSMC are largely unknown. Transforming growth factor beta (TGFbeta), a key factor present in the vessel wall in the early phases of arterial response to injury, plays an important role in modulating lesion formation. Because both CRP2 and TGFbeta are mediators of VSMC responses, we examined the possibility that TGFbeta might regulate CRP2 expression. TGFbeta significantly induced CRP2 mRNA and protein expression in VSMCs. Promoter analysis identified a conserved cAMP-responsive element (CRE)-like site (TAACGTCA) in the Csrp2 promoter that was critical for basal promoter activity and response to TGFbeta. Gel mobility shift assays revealed that mainly ATF2 bound to this CRE-like element, and mutation of the CRE sequences abolished binding. TGFbeta enhanced the activation of ATF2, leading to increased phospho-ATF2 levels within the DNA-protein complexes. Furthermore, ATF2-transactivated Csrp2 promoter activity and TGFbeta enhanced this activation. In addition, a phosphorylation-negative ATF2 mutant construct decreased basal and TGFbeta-mediated Csrp2 promoter activity. Our results show for the first time in VSMC that TGFbeta activates ATF2 phosphorylation and Csrp2 gene expression via a CRE promoter element.
Lin
Da-Wei
DW
Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
Chang
Il-Chi
IC
Tseng
Alan
A
Wu
Meng-Ling
ML
Chen
Chung-Huang
CH
Patenaude
Cassandra A
CA
Layne
Matthew D
MD
Yet
Shaw-Fang
SF
D000199:Actins / Q000235:genetics / Q000378:metabolism; D051698:Activating Transcription Factor 2 / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001158:Arteries / Q000293:injuries / Q000378:metabolism; D002465:Cell Movement / Q000235:genetics; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000235:genetics / Q000378:metabolism; D060588:LIM Domain Proteins; D051379:Mice; D009124:Muscle Proteins / Q000096:biosynthesis* / Q000235:genetics; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D009154:Mutation; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics; D010766:Phosphorylation; D051381:Rats; D020218:Response Elements / Q000235:genetics; D015533:Transcriptional Activation / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000378:metabolism*
D000199:Actins; D051698:Activating Transcription Factor 2; C497106:Atf2 protein, mouse; C497107:Atf2 protein, rat; C484376:Csrp2 protein, mouse; C484375:Csrp2 protein, rat; D060588:LIM Domain Proteins; D009124:Muscle Proteins; D009687:Nuclear Proteins; D016212:Transforming Growth Factor beta