Preclinical characterization of THR-123 to induce pancreatic beta cell regeneration (Phase I)

胰腺的外分泌（腺泡/导管）区室被假设为 具有产生新B细胞能力的细胞。这种祖细胞的激活可能会导致新的 B细胞通过分化形成，而不是重新编程。我们假设，如果胰腺 当存在祖细胞时，它们会对TGF-β家族成员骨形态发生蛋白7（BMP-7）产生应答 具有双重TGF-β抑制和BMP刺激能力。这一假设是根据广泛报道的 这两种协同作用之间的联系以及多个组织中祖细胞库的扩大。我校 的迈阿密/糖尿病研究所（UM/DRI）合作伙伴现在报道，BMP-7介导体外 将人非内分泌胰腺组织转化为在体外和体外都有功能的内分泌细胞， in vivo.这个过程需要激活祖细胞样细胞，共表达PDX1和ALK 3，BMP-7 受体的此外，我们已经证实：（1）THR-123（一种ALK 3激动剂环肽，具有BMP-7样 活性）可以诱导相同的效果;和（2）ALK 3 +/Pdx 1+细胞也存在于小鼠胰腺中， 为我们提供了测试内源性再生的可行性，在一个不涉及 移植初步数据表明，给予四氧嘧啶治疗的小鼠THR-123注射的每日方案 糖尿病小鼠相对于盐水处理的对照显著降低高血糖症。免疫荧光分析 治疗的小鼠表现出小的胰岛样结构，增殖率高度增加，这在很大程度上是不存在的。 生理盐水处理的对照组。我们的研究结果与THR-123刺激细胞凋亡的假设一致。 从祖细胞样细胞产生新的胰岛-假设我们的UM/DRI同事完全 在一个平行项目的背景下进行剖析。无论作用机制如何，观察到的 THR-123对b细胞形成和增强血糖控制的作用保证了一个专注于 证实这种小分子作为诱导动物B细胞再生的治疗先导物， 人体组织模型因此，第一阶段建议的总体目标是确认THR的适用性- 123用于临床开发，具有单一特定目的（THR-123诱导的b细胞再生的确认 在糖尿病小鼠和活的人胰腺切片中）。总之，我们将进行剂量依赖性和时间过程 研究证实了我们对小鼠模型体内以及体内B细胞新生的初步观察， 培养的人类胰腺切片-一种新型的分析工具， 研究所（DRI）和nPOD（糖尿病胰腺捐赠者网络），允许实时 B细胞在其完整胰腺小生境内再生的研究。如果成功，这些研究将 无缝过渡到旨在进行完整临床前ADME-Tox（吸附， 分布、代谢、排泄和毒性）和药代动力学（PK）特征，目的是 向美国食品药品监督管理局（FDA）提交研究性新药（IND）申请。 胰腺内的常驻祖细胞样细胞可以通过一种细胞因子原位激活， 简单的非遗传干预可以为设计潜在的变革性疗法打开大门， 糖尿病

The exocrine (acinar/ductal) compartment of the pancreas has been hypothesized to harbor progenitor cells with the ability to give rise to new b-cells. The activation of such progenitors may potentially result in new b-cell formation through differentiation, rather than reprogramming. We hypothesized that, if pancreatic progenitors existed, they would respond to bone morphogenetic protein 7 (BMP-7), a TGF-b family member with dual TGF-b inhibition and BMP stimulation abilities. This hypothesis was premised on the widely reported link between these two concerted actions and expansion of progenitor pools in multiple tissues. Our University of Miami/Diabetes Research Institute (UM/DRI) partners have now reported that BMP-7 mediates the in vitro conversion of human non-endocrine pancreatic tissue into endocrine cells that are functional both in vitro and in vivo. This process entails the activation of progenitor-like cells that co-express PDX1 and ALK3, a BMP-7 receptor. Furthermore, we have confirmed that: (1) THR-123 (an ALK3 agonist cyclic peptide with BMP-7-like activity) can induce the same effect; and (2) ALK3+/Pdx1+ cells are also present in the mouse pancreas, which affords us the possibility of testing the feasibility of endogenous regeneration in a setting not involving transplantation. Preliminary data indicate that a daily regimen of THR-123 injections administered to alloxan-treated diabetic mice drastically reduces hyperglycemia vs. saline-treated controls. Immunofluorescence analyses of treated mice show small islet-like structures with highly increased proliferation rates, which are largely absent from saline-treated controls. Our results are consistent with the hypothesis that THR-123 stimulates the generation of new islets from progenitor-like cells –a hypothesis that our UM/DRI associates are fully dissecting in the context of a parallel project. Regardless of the mechanism of action, the observed action of THR-123 on b-cell formation and enhanced glycemic control warrants the conduct of a project focused on the validation of this small molecule as a therapeutic lead for the induction of b-cell regeneration in animal and human tissue models. Thus, the general objective of this Phase I proposal is to confirm the suitability of THR- 123 for clinical development, with a single specific aim (Confirmation of THR-123-induced b-cell regeneration in diabetic mice and live human pancreatic slices). In short, we will conduct dose-dependence and time-course studies to confirm our preliminary observations on b-cell neogenesis in murine models in vivo as well as in cultured human pancreatic slices –a novel analytical tool developed as a collaboration between the Diabetes Research Institute (DRI) and nPOD (Network of Pancreatic Donors with Diabetes) that allows for the real-time study of the regeneration of b-cells within their intact pancreatic niche. If successful, these studies will seamlessly transition to a Phase II proposal aimed at conducting a full preclinical ADME-Tox (adsorption, distribution, metabolism, excretion and toxicity) and pharmacokinetic (PK) profile of THR-123 with the goal of submitting an investigational new drug (IND) application to the Food and Drug Administration (FDA). The demonstration that resident progenitor-like cells within the pancreas can be activated in situ through a simple non-genetic intervention could open the door to the design of potentially transformative therapies for diabetes.