Transforming growth factor β up-regulates cysteine-rich protein 2 in vascular smooth muscle cells via activating transcription factor 2
Transforming growth factor β up-regulates cysteine-rich protein 2 in vascular smooth muscle cells via activating transcription factor 2
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DOI：
10.1074/jbc.m801621200
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发表时间：
2008-05-30
影响因子：
4.8
通讯作者：
Yet, Shaw-Fang
中科院分区：
文献类型：
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作者：
Lin, Da-Wei;Chang, Il-Chi;Yet, Shaw-Fang
CRP 2（富含半胱氨酸蛋白）是血管平滑肌细胞（VSMC）表达的仅LIM蛋白。CRP 2与肌动蛋白细胞骨架结合，并与细胞核中的转录因子相互作用以介导平滑肌细胞基因表达。使用Csrp 2（小鼠CRP 2基因的基因符号）缺陷小鼠，我们先前证明了CRP 2的缺乏增强了血管平滑肌细胞迁移，并增加动脉损伤后新生内膜的形成。尽管其在血管损伤中的重要性，但控制VSMC中CRP 2表达的分子机制在很大程度上是未知的。转化生长因子β（TGF β）是动脉对损伤反应早期存在于血管壁中的关键因子，在调节病变形成中起重要作用。由于CRP 2和TGF β都是VSMC反应的介质，我们研究了TGF β可能调节CRP 2表达的可能性。TGF β可显著诱导VSMCs CRP 2 mRNA和蛋白表达。启动子分析确定了Csrp 2启动子中保守的cAMP反应元件（CRE）样位点（TAACGTCA），该位点对基础启动子活性和对TGF β的反应至关重要。凝胶迁移率变动分析表明，主要是ATF 2结合到这个CRE样元素，和CRE序列的突变废除结合。TGF β增强了ATF 2的活化，导致DNA-蛋白质复合物内磷酸化ATF 2水平增加。此外，ATF 2反式激活的Csrp 2启动子活性和TGF β增强了这种激活。此外，磷酸化阴性的ATF 2突变体构建体降低了基础和TGF β介导的Csrp 2启动子活性。我们的研究结果首次表明，在VSMC中，TGF β通过CRE启动子元件激活ATF 2磷酸化和Csrp 2基因表达。
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 (TGF beta), 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 TGF beta are mediators of VSMC responses, we examined the possibility that TGF beta might regulate CRP2 expression. TGF beta 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 TGF beta. Gel mobility shift assays revealed that mainly ATF2 bound to this CRE-like element, and mutation of the CRE sequences abolished binding. TGF beta enhanced the activation of ATF2, leading to increased phospho-ATF2 levels within the DNA-protein complexes. Furthermore, ATF2-transactivated Csrp2 promoter activity and TGF beta enhanced this activation. In addition, a phosphorylation- negative ATF2 mutant construct decreased basal and TGF beta-mediated Csrp2 promoter activity. Our results show for the first time in VSMC that TGF beta activates ATF2 phosphorylation and Csrp2 gene expression via a CRE promoter element.