The Role of Telomerase in Calcific Aortic Valve Disease

项目总结 该项目将检验端粒酶逆转录酶(TERT)非规范活性的假设。 通过诱导钙化性主动脉瓣病(CAVD)的成骨细胞重编程促进钙化 瓣膜间质细胞(VICs)。这一前提是从我们的初步数据以及从 别人的工作。首先，端粒酶逆转录酶在人间充质干细胞中的异位表达启动了这些细胞 向下分化成骨系。第二，多项研究表明，TERT发挥了非典型性-- CAL的作用是诱导基因表达，包括激活成骨基因；这些活动是 与TERT的端粒延伸功能完全分开。第三，我们的初步数据显示，TERT高度 与健康瓣膜相比，在CAVD瓣膜组织中表达，存在于从CAVD瓣膜分离的VIC中， 并且在健康的VIC中表达上调，这些VIC在促进成骨分化的条件下培养。 第四，在体外模型中，TERT的基因缺失抑制了钙化，而TERT的敲除减少了 成骨转录因子RUNX2的水平。最后，我们提供的证据表明，STAT5 可能参与TERT介导的成骨细胞重编程激活。我们的数据发现了一种新的机械- 机械论在CAVD发病中的作用。这项建议的目标是确定TERT对CAVD的贡献 通过它的非规范行为。具体目标1将检验TERT需要诱导的假设 静止的受害者转变为钙化的受害者。我们预计，TERT的基因缺失可以预防 通过阻止静止的健康VIC向成骨钙化的表型转换来防止瓣膜钙化- 英格·维克。特定目标2将检验STAT5诱导TERT表达的假设，以及STAT5和STAT5一起 TERT协同诱导成骨基因的转录。我们预计完成这些补充工作- TRAIL研究将确定一种新的调控CAVD发病机制，并将突出一种新的非CAVD发病机制。 端粒酶逆转录酶在异位钙化中的非作用。

PROJECT SUMMARY This project will test the hypothesis that non-canonical activities of telomerase reverse transcriptase (TERT) promote calcification in calcific aortic valve disease (CAVD) by inducing the osteogenic reprogramming of valve interstitial cells (VICs). Premise for this has been established from our preliminary data as well as from the work of others. First, ectopic expression of TERT in human mesenchymal stem cells primes these cells to differentiate down the osteogenic lineage. Second, multiple studies have shown that TERT exerts non-canoni- cal functions that act to induce gene expression, including activation of osteogenic genes; these activities are entirely separate from TERT’s telomere-extending functions. Third, our preliminary data shows TERT is highly expressed in CAVD valve tissues compared to healthy valves, is present in VICs isolated from CAVD valves, and is upregulated in healthy VICs that are cultured under conditions that promote osteogenic differentiation. Fourth, genetic deletion of TERT inhibits calcification in an in vitro model, and knockdown of TERT reduces levels of the osteogenic transcription factor RUNX2. Lastly, we provide evidence that suggests that STAT5 may be involved in the TERT-mediated activation of osteogenic reprogramming. Our data identify a new mech- anism driving CAVD pathogenesis. The objective of this proposal is to define TERT’s contribution to CAVD through its non-canonical actions. Specific Aim 1 will test the hypothesize that TERT is required for inducing the transition of quiescent VICs into calcifying VICs. We expect that genetic deletion of TERT protects against valvular calcification by preventing the phenotypic switch of a quiescent healthy VIC into an osteogenic calcify- ing VIC. Specific Aim 2 will test the hypothesis that STAT5 induces TERT expression, and together STAT5 and TERT cooperate to induce transcription of osteogenic genes. We expect the completion of these complemen- tary studies will identify a novel mechanism regulating CAVD pathogenesis, and will highlight a novel non-ca- nonical role for TERT in ectopic calcification.