Inhibiting Bcl-2-regulated intestinal fibrosis in models of Crohn’s Disease

纤维化是许多慢性疾病中器官衰竭的最终常见途径，导致美国每年超过1420亿美元的医疗费用。肠纤维化导致克罗恩病需要手术治疗，三分之二的患者需要手术治疗。尽管这对美国的医疗保健和克罗恩病患者产生了巨大的影响，但我们没有针对肠道纤维化的药物治疗。我们的初步数据表明，针对Bcl-2信号通路的小分子可以抑制肠成纤维细胞的活化。该提案的目的是验证Bcl-2信号传导作为肠纤维化的重要途径。这项研究计划的长期目标是开发Bcl-2抑制剂，这将导致克罗恩病肠道纤维化的有效药物治疗。我们的初步数据表明，候选Bcl-2抑制剂在体外和人类肠道类器官中抑制人类肠道肌成纤维细胞活化。然而，这些化合物具有有限的效力，并且在小鼠中全身暴露具有潜在毒性。现有的Bcl-2抑制剂navitoclax已被证明对人类安全，目前正处于癌症的2期临床试验中。我们建议对现有化合物进行改进，以增强化合物效力和肠道特异性，从而降低全身毒性。在目标1中，我们将迭代开发和测试这些化合物的新型变体的体外靶向特异性和抗纤维化活性。使用TGFβ（细胞因子活化）和基质硬度（机械活化），在两种独立的肌成纤维细胞活化模型中显示效价。在目标2中，我们将通过评估口服吸收到肠道中以及血浆和肝微粒体中的化合物不稳定性来优化目标1中最有前途的Bcl-2抑制剂的药代动力学特性。在目标3中，我们将确定有希望的候选化合物的最大耐受剂量，并在小鼠中进行PK和PD测试。有前途的肠道选择性化合物将逐步测试这些化合物在两种啮齿动物模型，鼠伤寒沙门氏菌肠纤维化小鼠模型，和大鼠三硝基苯磺酸（TNBS）模型肠纤维化的生物功效。拟议的研究是创新的，因为它们将产生肠道选择性化合物，抑制一种新的抗纤维化途径，并在两种啮齿动物模型中严格测试最佳候选物。这项研究提案的重要性在于，它有可能通过在器官纤维化中验证这一途径来影响患者护理，这是克罗恩病和大多数形式的慢性器官衰竭（包括肾衰竭和肝硬化）中一个重要的未满足的临床需求。

Fibrosis is the final common pathway to organ failure in many chronic diseases, leading to over $142 billion in annual medical costs in the United States. Intestinal fibrosis drives the need for surgery in Crohn's disease, which is required in two-thirds of all patients. Despite this immense impact on U.S. healthcare and patients with Crohn's disease, we have no medical therapies for intestinal fibrosis. Our preliminary data show that small molecules targeting the Bcl-2 signaling pathway can inhibit the activation of intestinal fibroblasts. The objective of this proposal is to validate Bcl-2 signaling as an important pathway for intestinal fibrosis. The long-term objective of this research program is to develop inhibitors of Bcl-2 that will lead to effective medical therapies for intestinal fibrosis in Crohn's disease. Our preliminary data demonstrate that candidate Bcl-2 inhibitors inhibit human intestinal myofibroblast activation in vitro and in human intestinal organoids. However, these compounds have limited potency, and potential toxicity from systemic exposure in mice. An existing Bcl-2 inhibitor, navitoclax, has been proven safe in humans and is now in phase 2 clinical trials for cancer. We propose to improve upon the current compounds to enhance compound potency and gut specificity to reduce systemic toxicity. In Aim 1, we will iteratively develop and test novel variants of these compounds for in vitro target specificity and anti-fibrotic activity. Potency will be shown in two independent models of myofibroblast activation, using TGFβ (cytokine activation) and matrix stiffness (mechanical activation). In Aim 2, we will optimize the pharmacokinetic properties of the most promising Bcl-2 inhibitors from Aim 1 by evaluating oral absorption into the gut and compound instability in plasma and liver microsomes. In Aim 3, we will determine the maximum tolerated dose of promising candidate compounds, and perform PK and PD testing in mice. Promising gut-selective compounds will progress to stepwise testing of the biologic efficacy of these compounds in two rodent models, the Salmonella typhimurium mouse model of intestinal fibrosis, and the rat trinitrobenzene sulfonic acid (TNBS) model of intestinal fibrosis. The proposed studies are innovative in that they will generate gut-selective compounds that inhibit a novel antifibrotic pathway, and rigorously test the best candidates in two rodent models. This research proposal is significant in that it has the potential to impact patient care by validating this pathway in organ fibrosis, a significant unmet clinical need in Crohn's disease and in most forms of chronic organ failure, including kidney failure and liver cirrhosis.