Vascular injury induces posttranscriptional regulation of the Id3 gene - Cloning of a novel Id3 isoform expressed during vascular lesion formation in rat and human atherosclerosis
Vascular injury induces posttranscriptional regulation of the Id3 gene - Cloning of a novel Id3 isoform expressed during vascular lesion formation in rat and human atherosclerosis
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DOI：
10.1161/01.atv.21.5.752
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发表时间：
2001-05-01
影响因子：
8.7
通讯作者：
McNamara, CA
中科院分区：
文献类型：
--
作者：
Matsumura, ME;Li, F;McNamara, CA
调节血管平滑肌细胞（SMC）对损伤的反应增殖的分子机制知之甚少。已知螺旋-环-螺旋转录因子的DNA结合（Id）抑制剂类的成员调节多种细胞类型的生长;然而，尚未研究SMC和血管病变中各种Id基因的表达。本研究利用酵母双杂交系统从培养的大鼠主动脉平滑肌细胞文库中克隆Id基因。通过使用普遍存在的E蛋白作为诱饵，Id 3和一个新的异构体1d 3（Id 3a）被克隆。Id 3a是Id 3基因可变剪接的产物，导致包含115-bp的“编码内含子”，其编码Id 3a蛋白的独特的29个氨基酸的羧基末端。与Id 3不同，Id 3a mRNA在正常大鼠颈动脉中未检测到。然而，球囊损伤后，Id 3a在整个新生内膜层中大量表达。此外，在人颈动脉粥样硬化斑块中检测到Id 3a的人类同源物（Id 3L）的mRNA。腺病毒介导的这些Id 3亚型在培养的大鼠主动脉平滑肌细胞的过度表达表明，与AdLacZ感染的细胞相比，用过表达Id 3a（与Id 3相反）的腺病毒感染的平滑肌细胞导致细胞数量显著减少。DNA片段分析表明，SMC活力的这种下降是由于过表达Id 3a的腺病毒感染的细胞中凋亡活性增加。这些结果提供的证据表明，选择性剪接的Id 3基因可能是一个重要的机制，其中新生内膜平滑肌细胞生长在血管病变形成衰减。
The molecular mechanisms that regulate the proliferation of smooth muscle cells (SMCs) of the vasculature in response to injury are poorly understood. Members of the inhibitor of DNA binding (Id) class of helix-loop-helix transcription factors are known to regulate the growth of a variety of cell types; however, the expression of the various Id genes in SMCs and in vascular lesions has not been examined. In the present study, the yeast 2-hybrid system was used to clone Id genes from a cultured rat aortic SMC library. By use of ubiquitous E proteins as bait, Id3 and a novel isoform of 1d3 (Id3a) were cloned. Id3a is the product of alternative splicing of the Id3 gene, resulting in inclusion of a 115-bp "coding intron," which encodes a unique 29-amino acid carboxyl terminus for the Id3a protein. Unlike Id3, Id3a mRNA was not detected in the normal rat carotid artery. However, after balloon injury, Id3a was abundantly expressed throughout the neointimal layer. In addition, mRNA of the human homologue of Id3a (Id3L) was detected in human carotid atherosclerotic plaques. Adenovirus-mediated overexpression of these Id3 isoforms in cultured rat aortic SMCs revealed that infection of SMCs with an adenovirus overexpressing Id3a (in contrast to Id3) resulted in a significant decrease in cell number versus AdLacZ-infected cells. DNA fragmentation analysis suggested that this decrease in SMC viability was due to increased apoptotic activity in cells infected with adenovirus overexpressing Id3a. These results provide evidence that alternative splicing of the Id3 gene may represent an important mechanism by which neointimal SMC growth is attenuated during vascular lesion formation.