Epigenetic regulation of lineage specification in colon epithelial cells

项目摘要 结肠是一个反应组织，上皮细胞每3-4天更换一次。结肠致力于 为自我更新和分化成专门细胞类型而分裂的干细胞。分化结肠细胞 执行不同的功能，包括吸水和粘液分泌。在许多组织中， 由包括组蛋白修饰在内的表观遗传机制驱动。组蛋白H3在赖氨酸36处的甲基化（H3 K36） 与转录活性位点的基因体相关。H3 K36甲基化有助于分化 以及干细胞在快速更新的组织（包括血液和睾丸）中的维持。根据初步数据，我 假设H3 K36甲基化控制细胞命运决定并增强结肠上皮细胞身份 细胞，特别是结肠细胞和杯状细胞谱系。为了解决这个假设，我将追求两个具体目标。 首先，我计划表征结肠上皮细胞中的H3 K36甲基化特征。第二，我将确定 H3 K36甲基化在结肠细胞身份中的功能作用。不过，建立直接联系 由于系统中的冗余，特定的组蛋白修饰和细胞过程是具有挑战性的，我可以 通过利用在癌症中首次发现的赖氨酸（K）到甲硫氨酸（M）突变来克服这一障碍 患者精确抑制H3 K36甲基化。我会联合收割机使用多种尖端工具 并在小鼠和类器官模型系统中操纵H3 K36甲基化，以促进对 染色质和谱系特化。我还将利用新的分选方案来纯化不同的结肠 用于比较表观遗传和转录分析的细胞群。总的来说，这项工作意义重大 因为它将确立H3 K36甲基化在控制细胞类型特异性基因表达中的作用， 结肠中的血统决定。揭示组蛋白修饰在结肠稳态中的作用是第一步 了解这些调节机制如何在结肠炎/癌症等疾病中分解， 影响人类健康。

PROJECT SUMMARY The colon is a responsive tissue, and the epithelium replaces itself every 3-4 days. The colon has dedicated stem cells that divide for self-renewal and differentiation into specialized cell types. Differentiated colon cells perform distinct functions including water absorption and mucus secretion. In many tissues, differentiation is driven by epigenetic mechanisms including histone modifications. Methylation of histone H3 at lysine 36 (H3K36) is associated with gene bodies at sites of transcriptional activity. H3K36 methylation contributes to differentiation and stem cell maintenance in rapidly renewing tissues including blood and testes. Based on preliminary data, I hypothesize that H3K36 methylation governs cell fate decisions and reinforces cell identity in colon epithelial cells, specifically colonocyte and goblet cell lineages. To address this hypothesis, I will pursue two specific aims. First, I plan to characterize the H3K36 methylation signature in colon epithelial cells. Second, I will determine the functional role of H3K36 methylation in colon cell identity. Although, establishing a direct connection between specific histone modifications and cellular processes is challenging due to redundancies in the system, I can overcome this obstacle by taking advantage of a lysine (K)-to-methionine (M) mutation first discovered in cancer patients to precisely suppress H3K36 methylation. I will combine multiple cutting-edge tools to specifically trace and manipulate H3K36 methylation in mice and organoid model systems to advance the understanding of chromatin and lineage specification in the colon. I will also utilize novel sorting protocols to purify distinct colon cell populations for comparative epigenetic and transcriptional analysis. Collectively, this work is significant because it will establish the role of H3K36 methylation in controlling cell-type specific gene expression and lineage decisions in the colon. Revealing the role histone modifications play in colon homeostasis is the first step to understanding how these regulatory mechanisms break down in diseases such as colitis/cancer and could impact human health.