Regulation of pancreas organoid plasticity: new strategies for diabetes

自从大约世纪前发现胰岛素以来，新发糖尿病病例出现了惊人的增长，但糖尿病的唯一治疗方法仍然是基于通过注射或泵输送胰岛素。虽然胰岛素给药可以成功地控制糖尿病症状，但并发症的风险非常高，并且所需的持续血糖管理可能是患者生活中的真实的负担。再生医学通过替代对血糖水平做出反应并产生胰岛素的β细胞，为糖尿病的治愈性治疗提供了新的希望。然而，替代细胞的来源，它们的生产效率以及它们在体内的工作情况仍在调查中。最近的证据表明，胰腺的导管细胞在糖尿病中不会受损，当给予正确的触发时，可以转变为其他细胞类型。导管细胞可以在体外长期生长，作为3D培养中的“类器官”。我们和其他人已经表明，当在特殊条件下生长或经过遗传修饰以产生负责在胚胎中制造β细胞的三种关键蛋白质（Ngn 3/Pdx 1/MafA）时，导管细胞会变成β样细胞。在我们的实验室中，我们有令人兴奋的证据表明，所产生的细胞的转化效率和功能性与“真实的”成熟β细胞不匹配的原因首先是，因为并非所有细胞都对成为β细胞的信号有同样的反应，其次，由于对Ngn 3，Pdx 1和MafA起作用的强烈降解机制，在它们有机会工作之前使它们失活。我们相信，通过鉴定可以转化为β细胞的细胞，并发现如何稳定Ngn 3，Pdx 1和MafA，我们将能够提高治愈糖尿病的机会。在这个建议中，我们要解决这些问题：什么是调节前内分泌因子稳定性的蛋白酶体机制？溶酶体如何调节前内分泌因子？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？总之，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。我们希望我们的研究结果为开发新的，更有效的策略来补充糖尿病患者丢失的β细胞铺平道路，以实现糖尿病的最终治疗目标：“无糖尿病”的生活。

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.