YY1 FUNCTIONS IN VASCULAR SMOOTH MUSCLE CELLS

YY1 在血管平滑肌细胞中的功能

• 批准号: 6629021
• 负责人: ANNY A USHEVA-SIMIDJIYSKA
• 金额: $ 30.3万
• 依托单位: BETH ISRAEL DEACONESS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-02-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6629021
• 关键词: DNA replication; cell cycle; cell migration; cell proliferation; cytokine; gene expression; gene interaction; genetic mapping; genetic promoter element; genetic transcription; growth factor; human tissue; pathologic process; polymerase chain reaction; restenosis; southern blotting; transcription factor; tumor suppressor genes; vascular smooth muscle

The long term goals of this project are to elucidate the molecular mechanisms underlying the abnormal liferation and migration of vascular smooth muscle (VSM) cells that is induced by acute arterial injury and leads to restenosis. The striking morphological similarities between cells in restenosis injury and cancer cells suggest that many of the same mechanisms may be responsible for abnormal growth of both types of cells. We have recently obtained evidence that overexpression of the transcription factor Yin Yang 1(YY1) in G0/G1-arrested coronary artery smooth muscle cells (CASMC) activates DNA synthesis. In cells that overexpress both YY1 and Rb, however, level of DNA synthesis falls back to normal levels. We also found that in growth arrested CASMC a significant portion of YY1 is in a complex with Rb but not in S-phase cultures and that recombinant Rb physically, directly interacts with YY1, destabilizing YY1's interaction with DNA. Moreover we found that Rb inhibits YY1 dependent transcription in vitro. The preliminary data suggest that YY1 is an important downstream target of the Rb pathway in CASMC and that the interaction of Rb and YY1 is likely to be cell cycle specific in vivo. It suggests that, as part of a complex with Rb, YY1 may participate in checkpoint functions that regulate the transition from a contractile to a "proliferative" phenotype at the level of transcription. We hypothesize that overexpression of YY1 induced by inflammatory cytokines and growth factors and/or disruption of the interaction between Rb and YY1 may alter gene expression and perhaps even cause abnormal CASMC growth after arterial injury. The Specific Aims of this proposal are: 1.0. To characterize the Rb-YY1 interaction and the effect of the YY1-Rb interaction on YY1's transcription factor function in the context of cellular promoters. 2.0 to study the functional consequences of the deregulated expression of YY1 in human CASMC. At present, understanding of and potential strategies to prevent the abnormal growth and migration of VSM cells are directly extrapolated from knowledge obtained from other cell systems, particularly from cancer cells in which cell cycle checkpoints are abrogated and normal cell cycle progression is lost. Little if any experimental evidence is available elucidating the mechanisms by which VSM cells themselves escape from G0 arrest and begin active proliferation. Therefore, it is essential to define the molecular mechanisms of VSM cell proliferation before one can consider specific strategies to prevent restenosis.

本项目的长期目标是阐明急性动脉损伤诱导血管平滑肌（VSM）细胞异常增殖和迁移并导致再狭窄的分子机制。再狭窄损伤细胞和癌细胞之间惊人的形态学相似性表明，许多相同的机制可能导致两种细胞的异常生长。我们最近获得的证据表明，转录因子阴阳1（YY1）在G0/ g1阻滞冠状动脉平滑肌细胞（CASMC）中过表达可激活DNA合成。然而，在YY1和Rb都过表达的细胞中，DNA合成水平回落到正常水平。我们还发现，在生长受阻的CASMC中，YY1的很大一部分与Rb形成复合物，但在s期培养中没有，重组Rb在物理上直接与YY1相互作用，破坏YY1与DNA的相互作用。此外，我们发现Rb在体外抑制YY1依赖性转录。初步数据表明，YY1是CASMC中Rb通路的重要下游靶点，Rb和YY1的相互作用在体内可能具有细胞周期特异性。这表明，作为与Rb复合体的一部分，YY1可能参与了在转录水平上调节从收缩表型向“增殖”表型转变的检查点功能。我们推测炎症细胞因子和生长因子诱导的YY1过表达和/或Rb和YY1之间相互作用的破坏可能改变基因表达，甚至可能导致动脉损伤后CASMC生长异常。本提案的具体目标是：1.0。在细胞启动子的背景下，表征Rb-YY1相互作用以及YY1- rb相互作用对YY1转录因子功能的影响。2.0研究YY1在人CASMC中失调控表达的功能后果。目前，对VSM细胞异常生长和迁移的理解和潜在策略是直接从其他细胞系统中获得的知识中推断出来的，特别是从癌细胞中，细胞周期检查点被取消，正常的细胞周期进程丢失。很少有实验证据能够阐明VSM细胞自身如何摆脱G0阻滞并开始活跃增殖的机制。因此，在考虑预防再狭窄的具体策略之前，有必要明确VSM细胞增殖的分子机制。