Regulation of pancreas organoid plasticity: new strategies for diabetes

自从近一个世纪前胰岛素被发现以来，新的糖尿病病例一直在以惊人的速度增长，但治疗糖尿病的唯一方法仍然是通过注射或泵送胰岛素。虽然胰岛素可以成功地控制糖尿病症状，但并发症的风险非常高，持续的血糖管理对患者的生活来说是一个真正的负担。通过替换失去的β细胞，再生医学为治愈糖尿病提供了新的希望。β细胞对血糖水平有反应，并产生胰岛素。然而，替代细胞的来源、生产效率以及它们在体内的工作效果都还在研究中。最近的证据表明，在糖尿病中没有受损的胰腺导管细胞，在适当的触发下可以转变成其他类型的细胞。导管细胞可以在体外作为“类器官”在3D培养中长期生长。我们和其他人已经证明，当在特殊条件下生长或通过基因改造产生胚胎中负责制造β细胞的三种关键蛋白质（Ngn3/Pdx1/MafA）时，导管细胞会转变为β样细胞。在我们的实验室中，我们有令人兴奋的证据表明，生成的细胞的转换效率和功能与“真正的”成熟β细胞不匹配的原因首先是，并非所有细胞对变成β细胞的信号都有同样的反应，其次，因为Ngn3、Pdx1和MafA上的强降解机制，在它们有机会工作之前就使它们失活。我们相信，通过识别可以转化为β细胞的细胞，并发现如何稳定Ngn3、Pdx1和MafA，我们将能够提高治愈糖尿病的机会。在本提案中，我们想要解决这些问题：什么是调节内分泌前因子稳定性的蛋白酶体机制？溶酶体是如何调节内分泌前因子的？这种机制在单细胞水平上的变化能否解释导管类器官的异质性？总的来说，这项研究计划将大大增加我们对导管细胞产生β细胞的认识。我们希望我们的发现为开发新的、更有效的策略来补充糖尿病患者失去的β细胞铺平道路，以实现糖尿病的最终治疗目标：“无糖尿病”生活。

Since the discovery of insulin almost a century ago, there has been an alarming increase in new diabetes cases, but the only treatment for diabetes is still based on delivering insulin via injections or pumps. While insulin administration can successfully control diabetic symptoms, the risk of complications is very high, and the continual blood sugar management required can be a real burden in patients' lives. Regenerative medicine offers new hopes of a curative treatment for diabetes by replacing lost beta cells, which respond to blood glucose levels and produce insulin. However, the source of replacement cells, the efficiency with which they can be produced and how well they work in the body are all still under investigation. Recent evidence suggests that the ductal cells of the pancreas, which are not damaged in diabetes, can change into other cell types when given the right trigger. Ductal cells can be grown long term outside the body as "organoids" in 3D culture. We and others have shown that when grown in special conditions or genetically modified to produce three key proteins responsible for making beta cells in the embryo (Ngn3/Pdx1/MafA), ductal cells change to beta-like cells. In our lab, we have exciting evidence that the reason the efficiency of conversion and functionality of the generated cells does not match "real" mature beta cells is firstly, because not all cells are equally responsive to the signals to become beta-cells, and secondly, because of the strong degradation mechanisms that operate on Ngn3, Pdx1 and MafA, inactivating them before they have a chance to work. We believe that by identifying the cells that can convert into beta-cells, and discovering how to stabilise Ngn3, Pdx1 and MafA we will be able to improve the chances of curing diabetes. In this proposal, we want to address these questions: What are the proteasomal mechanisms regulating proendocrine factors stability? How does the lysosome regulate the proendocrine factors? Can the variation of such mechanisms at a single cell level explain the heterogeneity of the ductal organoids? Altogether this research proposal will substantially increase our knowledge of beta cell generation from ductal cells. We hope that our findings pave the way for the development of new, more efficient strategies to replenish lost beta cells in diabetes patients, in order to achieve the ultimate therapy goal for diabetes: a "diabetes free" life.