Epigenetic Regulation of Kidney Development

描述(申请人提供)：一个完全分化的细胞是由它表达的基因定义的，最终是由它的生理功能定义的。这种正常的基因表达模式或转录组在疾病状态下被改变，以至于功能被扰乱，生长被解除调控，与其他细胞的交流受到影响。问题是，在没有基因突变的情况下，这些异常表达模式是如何建立和维持的？我们认为，基因组上的表观遗传修饰，特别是组蛋白甲基化，会影响疾病组织中基因表达的变化。为了探索这一假设，我们必须首先了解表观遗传修饰是如何在胚胎发育过程中印记的，因为细胞谱系的决定是做出的。此前，PI已经确定Pax2是肾上皮细胞中的一个关键的DNA结合蛋白。该实验室随后发现，PTIP是一种连接Pax2和组蛋白甲基化复合体的接头蛋白，可以在目标基因上印记阳性的表观遗传标记。在这项应用中，AIM 1将使用染色质免疫沉淀、下一代测序和特定的转基因小鼠品系来绘制Pax2/PTIP与基因组相互作用的位置，并将其与基因表达模式相关联。此外，我们有第一个真正的证据表明，以细胞特有的方式改变组蛋白甲基化途径可以导致慢性肾脏疾病。在目标2中，我们将确定PTIP和组蛋白甲基化在肾间质纤维化中的作用，并将其与已知的介导纤维化的转化生长因子-b信号通路相关联。虽然癌症和其他疾病状态的表观遗传变化有许多相关性，但我们的研究将首次研究表观遗传修改是否可以在没有其他突变或环境侮辱的情况下直接启动疾病状态。我们的初步数据强烈表明，他们可以做到这一点。

DESCRIPTION (provided by applicant): A fully differentiated cell is defined by the genes it expresses and, ultimately, by its physiological functions. This normal pattern of gene expression, or transcriptome, is altered in a diseased state such that function is perturbed, growth is deregulated, and communication with other cells affected. The question is, how are these abnormal expression patterns established and maintained in the absence of genetic mutations? We propose that epigenetic modifications on the genome, and specifically histone methylation, impact gene expression changes in diseased tissues. To explore this hypothesis, we must first understand how epigenetic modifications are imprinted during development of the embryo, as cell lineages decisions are made. Previously, the PI has identified Pax2 as a critical DNA binding protein in the renal epithelial lineage. The lab then discovered PTIP as an adaptor protein that links Pax2 to a histone methylation complex to imprint positive epigenetic marks on target genes. In this application, Aim 1 will use chromatin immunoprecipitation, next generation sequencing, and specific strains of genetically altered mice to map the sites of Pax2/PTIP interactions with the genome and to correlate this with gene expression patterns. Furthermore, we have the first real evidence that altering a histone methylation pathway in a cell specific manner can lead to chronic renal disease. In Aim 2, we will define the role of PTIP and histone methylation in renal interstitial fibrosis and correlate this with TGF-b signaling pathways that are known to mediate fibrosis. While there are many correlations of epigenetic changes in cancer and other disease states, our studies will address for the first time whether epigenetic modifications can directly initiate a disease state in the absence of other mutations or environmental insults. Our preliminary data strongly suggests that they can.