YY1 FUNCTIONS IN VASCULAR SMOOTH MUSCLE CELLS

YY1 在血管平滑肌细胞中的功能

• 批准号: 6498995
• 负责人: ANNY A USHEVA-SIMIDJIYSKA
• 金额: $ 29.42万
• 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 2004-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6498995
• 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.

该项目的长期目标是阐明急性动脉损伤引起的血管平滑肌（VSM）细胞异常生命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类型细胞的异常生长。 我们最近获得的证据表明，G0/G1 停滞的冠状动脉平滑肌细胞 (CASMC) 中转录因子阴阳 1 (YY1) 的过度表达可激活 DNA 合成。 然而，在过度表达 YY1 和 Rb 的细胞中，DNA 合成水平会回落到正常水平。 我们还发现，在生长停滞的 CASMC 中，YY1 的很大一部分与 Rb 形成复合物，但在 S 期培养物中则不然，并且重组 Rb 在物理上直接与 YY1 相互作用，从而破坏了 YY1 与 DNA 相互作用的稳定性。 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途径的重要下游靶标，并且Rb和YY1的相互作用可能是体内细胞周期特异性的。 这表明，作为与 Rb 复合物的一部分，YY1 可能参与检查点功能，在转录水平上调节从收缩表型到“增殖”表型的转变。 我们假设炎性细胞因子和生长因子诱导的 YY1 过度表达和/或 Rb 和 YY1 之间相互作用的破坏可能会改变基因表达，甚至可能导致动脉损伤后 CASMC 生长异常。 该提案的具体目标是： 1.0。表征细胞启动子背景下 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 研究人 CASMC 中 YY1 表达失调的功能后果。目前，对防止 VSM 细胞异常生长和迁移的理解和潜在策略直接从其他细胞系统获得的知识中推断出来，特别是从细胞周期检查点被废除且正常细胞周期进程丧失的癌细胞中获得的知识。 几乎没有任何实验证据可以阐明 VSM 细胞本身摆脱 G0 停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。