The Role of Autophagy in Intestinal Regeneration

项目总结/摘要 这些研究的主要目标是发现预防化疗相关肠道损伤的新方法。多克司- 柔比星是一种化疗药物，用于治疗患者的转移性癌症， 小鼠肠损伤模型。化疗有许多脱靶副作用，包括炎症， 称为粘膜炎的粘膜。患者通常表现为疼痛、呕吐和腹泻， 发病率恶化的症状降低了患者对治疗的依从性，并限制了医生对患者的治疗。 治疗性化疗剂量。没有有效的治疗方法来减轻粘膜炎，尽管有此需要， 对肠粘膜炎的研究有限。肠干细胞（ISC）损伤是小鼠肠上皮细胞损伤的一个共同特征。 各种损伤引起的肠粘膜损伤。与肠道再生过程相关的途径- 包括那些驱动细胞重塑，如自噬。阿霉素化疗前禁食 在小鼠中施用已经显示通过激活自噬保护肠干细胞免受DNA损伤。 此外，终末分化的潘氏细胞（PC）对损伤有抵抗力，可以去分化， 重建肠上皮的完整性虽然早期的细胞重建机制， 允许有丝分裂后的PC恢复到ISC状态是相对未知的，见解可以从 其他终末分化细胞类型的获得性可塑性。值得注意的是，自噬的早期激活是一个重要因素。 终末分化成纤维细胞体外重编程为多能干细胞的关键步骤。 这些发现强调了自噬在损伤保护和损伤恢复中的重要性 当保护是不可能的。本提案的目的1将阐明自噬在保护 抗阿霉素诱导的肠粘膜损伤。首先，雷帕霉素，一种诱导自噬的药物， 给予小鼠，以确定禁食的保护作用是否可以通过刺激Au- tophagy单独为了增强这些发现的可翻译性，禁食/自噬对肠损伤的影响 并且将在多柔比星敏感的转移性癌症模型中检查肿瘤反应性。目标2将执行- 自噬在损伤后PC介导的肠再生中的作用。两个PC特定基因 将产生改良的小鼠模型，以确定PC介导的肠道重建是否需要自噬。 一代该项目的长期目标是产生具有更广泛影响的可推广的突破， 用于上皮损伤导致的各种胃肠道疾病。所有的实验都将 在贝勒医学院进行，在众多核心设施的协助下， 设备和技术。该项目是医生科学家培训的有力工具，将促进利润， 在技术，批判性思维，沟通和指导方面的科学。

Project Summary/Abstract The main goal of these studies is to discover novel ways to prevent chemotherapy-related intestinal injury. Dox- orubicin is a chemotherapy drug administered to treat metastatic cancers in patients and is commonly used to model intestinal injury in mice. Chemotherapy has many off target side effects, including the inflammation of mucus membranes termed mucositis. Patients commonly present with pain, vomiting and diarrhea causing high morbidity. Worsening symptoms reduce patient adherence to treatment and limit physician administration of therapeutic chemotherapy doses. There are no effective therapies to attenuate mucositis, and despite the need, there is limited research on intestinal mucositis. Intestinal stem cell (ISC) damage is a common feature of murine intestinal mucosal damage by various insults. Pathways related to the regenerative process of the intestine in- clude those that drive cellular remodeling, such as autophagy. Fasting prior to doxorubicin chemotherapy ad- ministration in mice has been shown to protect intestinal stem cells from DNA damage by activating autophagy. Furthermore, terminally differentiated Paneth cells (PCs) are resistant to injury and can de-differentiate to help reestablish the integrity of the intestinal epithelium. While the early cellular reconstructive mechanisms that allow post-mitotic PCs to revert to an ISC state are relatively unknown, insights can be extrapolated from the acquired plasticity of other terminally differentiated cell types. Notably, the early activation of autophagy is an essential step in the reprograming of terminally differentiated fibroblasts into pluripotent stem cells invitro. These findings highlight the importance of autophagy in the protection from injury, and the recovery from injury when protection is not possible. Aim 1 of this proposal will elucidate the role of autophagy in the protection against doxorubicin-induced intestinal mucosal damage. First, rapamycin, an autophagy inducing drug, will be administered to mice to determine if the protective effects of fasting can be emulated by the stimulation of au- tophagy alone. To enhance the translatability of these findings the effect of fasting/autophagy on intestinal injury and tumor responsiveness will be examined in a doxorubicin-sensitive metastatic cancer model. Aim 2 will ex- amine the role of autophagy in PC-mediated intestinal regeneration following injury. Two PC-specific genetically modified mouse models will be generated to determine if autophagy is required for PC-mediated intestinal re- generation. The long-term goal of this project is to produce generalizable breakthroughs that have broader im- plications for the gamut of GI medical conditions that result from epithelial damage. All experiments will be conducted at Baylor College of Medicine, with the assistance of numerous core facilities with state-of-the-art equipment and technology. This project is strong vehicle for physician scientist training and will foster profi- ciency in technique, critical thinking, communication and mentorship.