The role of Paneth cell sirtuin 1 in intestinal tissue homeostasis and colorectal carcinogenesis.

项目摘要 结直肠癌(CRC)是世界上第三大被诊断的恶性肿瘤(1)。超过两倍于 所有病例和死亡都与可改变的环境风险因素有关(2)。特别是，CRC发病率 在较年轻的年龄(&lt；50岁)(3)有所增加。因此，将两者联系起来的新的基于目标的方法 需要建立遗传和环境因素来治疗这种肿瘤(4，5)。肠道 上皮细胞、肠道微生物和细菌之间的复杂相互作用维持了上皮内环境的稳定。 免疫细胞(6、7)。这些精心安排的相互作用的中断会导致炎症性疾病，如 结肠炎和结直肠癌。一种遗传因素，调节肠道上皮、微生物区系和 免疫细胞是sirtuin 1(SIRT1)，是高度保守的NAD家族中最保守的哺乳动物成员。 依赖性组蛋白脱乙酰酶和/或称为sirtuins的ADP-核糖基转移酶(8)。我们和其他人已经展示了 肠上皮细胞SIRT1调节肠道应激反应和组织稳态，这方面的不足 因子导致肠道炎症，肠道微生物组成紊乱，并改变易感性 环境儿童权利公约(9-13)。特别是，我们发现肠上皮SIRT1缺失会导致 潘氏细胞(11)的过度激活，肠道起源的先天免疫细胞对肠道微生物区系至关重要 调节和维持肠道干细胞生态位(14)。最近我们产生了一个Paneth细胞特异的SIRT1 用Defa6-Cre系(15)培育SIRT1等位基因的KO小鼠模型(SIRT1 PKO)，发现其升高 Paneth细胞标志物的表达、Paneth细胞数量的增加和对化学物质的增强保护 引起炎症。 本研究将探讨SIRT1在Paneth细胞中的作用以及缺失SIRT1对Paneth细胞的影响 环境对肠上皮动态平衡的影响。由于肠道微生物区系在 宿主免疫系统(16)，以及抗肿瘤免疫疗法的疗效(17-20)，它还将寻求 解析SIRT1对肠道微生物群的调节以及这种相互作用如何改变肠道和系统免疫 功能，这会影响抗肿瘤免疫和抗肿瘤免疫治疗的疗效。因此， 在潘氏细胞的背景下理解SIRT1在肠上皮细胞中的作用将有助于阐明 潘氏细胞的破坏会导致肠道微生物群的改变，免疫功能的改变，以及破坏 上皮细胞动态平衡。 研究的目的是： 目的1：确定Paneth细胞中SIRT1缺失是否扰乱肠道微生物区系，改变肠道免疫功能。 目的：探讨Paneth细胞SIRT1缺失是否会改变抗肿瘤免疫功能。 目的：探讨Flox和PKO小鼠不同的抗肿瘤免疫水平对其抗肿瘤效应的影响。 肿瘤免疫疗法。

Project Summary Colorectal cancer (CRC) represents the third most diagnosed malignancy in the world (1). More than two-fold of all cases and deaths are associated with modifiable environmental risk factors (2). In particular, CRC incidence has been increasing at younger ages (<50 years) (3). Therefore, novel target-based approaches that link both genetic and environmental factors need to be established for the treatment of this neoplasm (4, 5). Intestinal epithelial homeostasis is maintained by a complex interplay between epithelial cells, gut microorganisms, and immune cells (6, 7). Disruptions of these orchestrated interactions results in inflammatory disorders such as colitis and CRC. One genetic factor that modulates the interactions between gut epithelium, microbiota and immune cells is sirtuin 1 (SIRT1), the most conserved mammalian member of a family of highly conserved NAD+- dependent histone deacetylases and/or ADP-ribosyltransferases called sirtuins (8). We and others have shown that intestinal epithelial SIRT1 regulates intestinal stress response and tissue homeostasis, deficiency of this factor leads to intestinal inflammation, disruption of gut microbial composition, and altered susceptibility to environmentally CRC (9-13). Particularly, we found that deletion of intestinal epithelial SIRT1 results in hyperactivation of Paneth cells (11), intestine-originated innate immune cells important for gut microbiota regulation and intestinal stem cell niche maintenance (14). Recently we generated a Paneth-cell specific SIRT1 KO mouse model (SIRT1 PKO) by breeding SIRT1 floxed allele with Defa6-Cre line (15), and found elevated expression of Paneth cell markers, increased Paneth cell number, and enhanced protection against chemical induced inflammation. This study will investigate the role of SIRT1 in Paneth cells and how deficiency of SIRT1 in Paneth cells impacts environmental influences on intestinal epithelial homeostasis. Since gut microbiota plays a fundamental role on the host immune system (16), as well as the efficacy of anti-tumor immunotherapies (17-20), it will also seek to parse out SIRT1 regulation of gut microbiome and how this interaction can alter intestinal and systemic immune function, which can impact anti-tumor immunity and the efficacy of anti-tumor immunotherapies. Thus, understanding the role of SIRT1 in intestinal epithelial in the context of Paneth cells will shed light on to how disruptions on Paneth cells can result in changes of gut microbiome, altered immune functions, and disrupts epithelial homeostasis. The aims of the study are: Aim 1: To determine if SIRT1 deletion in Paneth cells disrupts gut microbiota and alters gut immunity. Aim 2: To explore if SIRT1 deletion in Paneth Cells alters anti-tumor immunity. Aim 3: To investigate if the differential anti-tumor immunity in Flox and PKO mice affects the efficacy of anti- tumor immunotherapies.