Piezo1介导生物钟基因Bmal1调控肠道干细胞参与UC肠上皮修复

Impaired healing of intestinal mucosa after inflammatory injury is a chief factor in the recurrence of ulcerative colitis. As we all know, Intestinal stem cells are critical for the healing of intestinal epithelial injury, while Bmal1 plays an important role in their rhythmic regeneration. Our previous study revealed that circadian clock disturbance is closely related to the severity of UC, and Bmal1 is the most closely circadian gene. However, the mechanism is still unclear. On the other hand, Mechanical microenvironment plays an important role in regulating the proliferation and differentiation of intestinal stem cells. We have confirmed that the mechanical gated ion channel Piezo1 protein is expressed in the intestinal stem cells, and is probably the key receptor for the mechanical signals of the intestinal stem cells. It has been found that the rhythmic expression of Piezo1 is controlled by Bmal1, suggesting that “biological -- mechanical signals” dialogue may play an important role in the regulation of intestinal stem cells. Piezo1 is probably the key node. This project will explore the important role of "Bmal1-- mechanical microenvironment --Piezo1" in the regulation of intestinal stem cell proliferation and differentiation in vitro and in vivo, from the perspective of normal and disease, so as to provide new therapeutic targets for improving UC epithelial healing.

肠上皮炎症损伤后修复不良是溃疡性结肠炎(UC）迁延不愈的重要原因。众所周知，肠道干细胞在肠上皮损伤后修复中至关重要，其节律性更新依赖于生物钟基因。我们前期研究证实，生物钟紊乱与UC的严重程度密切相关，其中生物钟基因Bmal1与症状相关性密切，但其机制尚不清楚。另一方面，机械微环境是调控肠道干细胞增殖分化的重要因素，我们证实机械门控离子通道Piezo1蛋白表达于肠道干细胞，很可能是肠道干细胞对机械信号的关键感受器。而有研究发现，Piezo1的节律性表达受到Bmal1控制，这提示我们，生物钟与力学信号的对话可能在肠道干细胞调控中有重要作用，Piezo1很可能是关键节点。本项目将在离体和在体不同水平，从正常和疾病不同角度，探讨“Bmal1--机械微环境--Piezo1”在肠上皮干细胞增殖分化调控中的重要作用，为改善UC上皮修复提供新的治疗靶点。

肠上皮炎症损伤后修复不良是溃疡性结肠炎(UC）迁延不愈的重要原因。生物钟与力学信号的对话可能在肠道干细胞调控中有重要作用，Piezo1很可能是关键节点。本项目将在离体和在体不同水平，从正常和疾病不同角度，探讨“Bmal1--机械微环境--Piezo1”在肠上皮干细胞增殖分化调控中的重要作用，为改善UC上皮修复提供新的治疗靶点。. 实施过程中进行了如下研究： 一、探究了生物钟基因 Bmal1 对于肠道干细胞增值分化和肠道炎症的影响；二、在体实验检测病理条件下昼夜节律紊乱对肠道干细胞增殖分化能力、肠上皮损伤和炎症情况的影响；三、探究了 piezo1 蛋白对于肠道炎症的影响；四、在体实验探究 Piezo1 对肠道干细胞增殖分化的影响；五、体外实验探究 piezo1 对肠道干细胞增殖分化的调控：六、探究 piezo1 蛋白与肠道上皮功能之间的关系；七、构建了 Lgr5-Cre Piezo1-Flox 的小鼠。. 结果显示：单纯Baml1蛋白对于肠道干细胞增殖分化和肠道炎症无显著影响，仅在肠道炎症的情况下对肠道干细胞增殖分化和炎症会产生影响。而piezo1蛋白在无肠道炎症的条件对于肠道增殖分化和肠道炎症就有显著影响，慢性炎症条件下该影响依旧显著。体内和体外实验均证实了piezo1能够显著影响干细胞的增殖分化。进一步的研究证明了piezo1对于肠道屏障功能的重要影响。该研究具有重大的应用前景，提示未来对于IBD患者的治疗和护理措施的选择：Baml1靶点会成为生物钟重要调控靶点，帮助减轻肠道炎症，帮助肠道上皮修复；同时piezo1靶点更具有重要意义，对钙蛋白的干预可能对于肠上皮的修复、炎症减轻和肠上皮功能恢复具有重要潜在价值。