Bioengineering approaches to map mechanotransduction in the living cell

项目总结/摘要 众所周知，干细胞分化和细胞命运受到机械力和力学的调节。 我们先前已经报道过，细胞的机械特性决定了应力诱导的细胞的伸展和分化。 胚胎干细胞（ESCs）。其他报告也证明了力对多能干细胞的影响。 细胞然而，力如何在染色质水平调节（多能）干细胞分化和细胞命运 仍然难以捉摸这是一个重要的问题，因为染色质是基因转录和DNA的枢纽 复制和DNA损伤修复，对多能干细胞自我更新和分化以及癌症至关重要 干细胞自我更新我们的初步结果染色质结构域拉伸，但不压缩迅速， 核蛋白LAP 2 β介导核纤层向染色质的力传递。此外，RNA 聚合酶II（Pol II）被募集并响应拉伸而延长，但不响应压缩和去甲基化 H3 K9 me 3的表达对于力诱导的基因上调是必需的。基于这些结果，我们提出了3个具体目标 阐明活细胞中的核机械生物学机制。目的1：确定染色质拉伸是否 目的2：验证H3 K9 me 3和H3 K9 ac在力诱导干细胞分化中的作用， 调节力诱导的多能干细胞基因转录;目的3：确定大应变是否诱导 端粒磨损有助于从正常干细胞向癌症干细胞的转变。我们的实验设计 是严格的，产生有见地的发现的可能性很高。长期目标是开发新的 干预恶性肿瘤等病理过程的方法和策略。

Project Summary/Abstract It is well known that stem cell differentiation and cell fate are regulated by mechanical forces and mechanics. We have reported earlier that cell mechanical properties dictate stress-induced spreading and differentiation in embryonic stem cells (ESCs). Other reports have also demonstrated the effect of forces on pluripotent stem cells. However, how force regulates (pluripotent) stem cell differentiation and cell fate at the level of chromatin remains elusive. This is an important question since the chromatin is the hub of gene transcription and DNA replication and DNA damage repair, critical for pluripotent stem cell self-renewal and differentiation and cancer stem cell self-renewal. Our preliminary results chromatin domain stretching but not compression rapidly and nuclear protein LAP2β mediates force transmission from nuclear lamina to chromatin. In addition, RNA polymerase II (Pol II) is recruited and elongated in response to stretching but not compression and demethylation of H3K9me3 is necessary for force-induced gene upregulation. Built on these results, we propose 3 specific aims to elucidate nuclear mechanobiology mechanisms in the living cells. Aim 1: To determine if chromatin stretching is necessary for force-induced stem cell differentiation; Aim 2: To test the hypothesis that H3K9me3 and H3K9ac regulate force-induced pluripotent stem cell gene transcription; Aim 3: To determine if large-strain induced telomere attrition contributes to transition from normal stem cells to cancer stem cells. Our experimental designs are rigorous and the likelihood of generating insightful discovery is high. The long-term goal is to develop novel approaches and strategies to intervene pathological processes like malignant tumors.