Roles of circadian rhythms in gastrointestinal systems

项目摘要 超过四分之一的美国工人是轮班工人，他们的昼夜节律经常被打乱， 增加胃肠道（GI）疾病的风险。昼夜节律影响基本GI 消化道上皮细胞的消化、免疫和再生过程。因此， 昼夜节律与从消化性溃疡到癌症的胃肠道疾病有关。最近的研究 证明了生物钟影响细胞周期，反之亦然，但性质和 这一联系的后果在很大程度上仍不为人所知。一个主要的限制是缺乏一个易于处理的 模型系统来研究这些相互作用的分子基础。为了解决这个问题，我们开发了 3D小鼠肠，或体外"迷你肠"，作为鉴定分子机制和 这种耦合的后果。该系统允许操纵和跟踪细胞周期和细胞周期。 作为肠道干细胞的生物钟成分经历分化成特化细胞。重要的是， 我们已经证明，小鼠肠具有强大的昼夜节律，并模仿 在小鼠肠道中观察到的基因消融反应。具体来说，我们证明了 潘氏细胞的生物钟通过细胞间WNT信号调节协调的细胞分裂周期 在类肠中，昼夜节律的消除导致肠隐窝发育中断。 在拟议的项目中，我们将确定：（1）细胞类型的昼夜节律在小细胞中的特定作用， （2）胃肠道生物钟和细胞间WNT信号介导的细胞间耦合 周期，（3）生物钟调节的上皮屏障功能，（4）生物钟和潘氏细胞- 介导对沙门氏菌感染的先天免疫应答。我们的研究成果将为 确定恢复昼夜节律钟依赖性成体干细胞的潜在靶点和时间方案 再生、上皮屏障功能和GI相关疾病的先天免疫应答。

PROJECT SUMMARY Over 1 in 4 American workers are shift workers with frequent disruptions in their circadian rhythms and increased risks of gastrointestinal (GI) diseases. Circadian rhythms influence fundamental GI processes, including digestion, immunity, and regeneration of the GI epithelium. Thus, disruption of circadian rhythms is associated with GI diseases ranging from peptic ulcers to cancer. Recent studies demonstrated that the circadian clock influences the cell cycle and vice versa, but the nature and consequences of this connection remain largely unknown. One major limitation is the lack of a tractable model system to investigate the molecular basis of these interactions. To address this, we developed 3D mouse enteroids, or an in vitro “mini-gut”, as a system to identify the molecular mechanisms and consequences of this coupling. This system allows manipulation and tracking of both cell cycle and circadian clock components as gut stem cells undergo differentiation into specialized cells. Importantly, we have demonstrated that mouse enteroids possess robust circadian rhythms, and mimic the response of gene ablation that is observed in mouse intestine. Specifically, we demonstrated that the circadian clock in Paneth cells regulate coordinated cell division cycles via intercellular WNT signaling in enteroids, and elimination of circadian rhythms results in disrupted development of intestinal crypts. In the proposed project, we will determine: (1) cell type-specific roles of circadian rhythms in the small intestine, (2) WNT signaling-mediated intercellular coupling between the GI circadian clock and cell cycle, (3) circadian clock-regulated epithelial barrier function, and (4) circadian clock and Paneth cell- mediated innate immune response to Salmonella infection. Our results will lay a foundation for identifying potential targets and temporal regimens to restore circadian clock-dependent adult stem cell regeneration, epithelial barrier function, and innate immune response for GI-related diseases.