Epigenetic Rejuvenation of Human Beta-Cells

描述(申请人提供)：糖尿病的流行已达到世界范围内的流行程度，并预计在未来几年将迅速增加，给发达国家和发展中国家的卫生保健预算带来巨大压力。糖尿病有两种主要形式，两种都与β细胞质量减少有关。目前还没有设计出在人体内增加β细胞质量的治疗方法，而且由于缺乏合适的捐赠者，β细胞的移植极其有限。由于这些原因，在体外或体内移植前或移植后增加功能性β细胞质量已成为糖尿病研究的“圣杯”。我们之前的研究清楚地表明，成年人类β细胞可以被诱导复制，而且--重要的是--细胞分裂后可以保持正常的葡萄糖反应。然而，所实现的复制率仍然很低，部分原因可能是已知的与年龄相关的β细胞复制能力的下降。W建议在我们先前发现的基础上，开发更有效的方法，通过诱导成年β细胞的复制，并通过恢复老化的β细胞的幼年功能特性来增加功能性β细胞的质量。我们将集中在非肿瘤性人类疾病以及与年龄相关的人类β细胞表型变化的研究中产生的机制。在目标1中，我们将针对显著的β细胞增生患者的基因改变，例如婴儿局灶性高胰岛素血症、Beckwith-Wiedemann综合征或多发性内分泌肿瘤。这些基因的表达将通过shRNA介导的基因抑制和位点特异性表观遗传靶向在人类β细胞中改变。在移植的人类胰岛中，将通过确定β细胞复制率和功能保留来评估成功与否。在目标2中，我们将通过绘制随年龄发生的β细胞表观基因组的变化来确定与年龄相关的β细胞功能和复制能力下降的机制。然后，选定的基因将作为目标1的靶点，以改善人类β细胞功能，如通过葡萄糖反应评估的那样。为了实现这些目标，我们将使用我们实验室已经建立或正在开发的尖端和新兴技术。研究团队结合了临床经验和分子生物学方面的专业知识，以及旨在增强β细胞复制的基因组修饰方面的丰富经验。通过以人类疾病和正常衰老中发现的变化为基础进行干预，这种方法将增加发现可以更快地转化为临床相关方案的机会。

DESCRIPTION (provided by applicant): The prevalence of Diabetes Mellitus has reached epidemic proportions world-wide and is predicted to increase rapidly in the years to come, putting a tremendous strain on health care budgets in both developed and developing countries. There are two major forms of diabetes and both are associated with decreased beta-cell mass. No treatments have been devised that increase beta-cell mass in vivo in humans, and transplantation of beta-cells is extremely limited due to lack of appropriate donors. For these reasons, increasing functional beta-cell mass in vitro, or in vivo prior to or after transplantatio, has become a "Holy Grail" of diabetes research. Our previous studies clearly show that adult human beta-cells can be induced to replicate, and - importantly - that cells can maintain normal glucose responsiveness after cell division. However, the replication rate achieved was still low, likely due in part to the known age-related decline in the ability of the beta-cell to replicate. W propose to build on our previous findings and to develop more efficacious methods to increase functional beta-cell mass by inducing replication of adult beta-cells, and by restoring juvenile functional properties to aged beta-cells. We will focus on mechanisms derived from studies of non- neoplastic human disease as well as age-related phenotypic changes in human beta-cells. In Aim 1, we will target the genes altered in patients with marked beta-cell hyperplasia, such as those suffering from Focal Hyperinsulinism of Infancy, Beckwith-Wiedemann Syndrome or Multiple Endocrine Neoplasia. Expression of these genes will be altered in human beta-cells via shRNA-mediated gene suppression and locus-specific epigenetic targeting. Success will be assessed in transplanted human islets by determination of beta-cell replication rate and retention of function. In Aim 2, we will determine the mechanisms of age-related decline in beta-cell function and replicative capacity, by mapping the changes in the beta-cell epigenome that occur with age. Selected genes will then be targeted as in Aim 1 to improve human beta-cell function, as assessed by glucose responsiveness. To accomplish these aims, we will use cutting-edge and emerging technologies that are already established or are being developed in our laboratories. The research team combines clinical experience with expertise in molecular biology and extensive experience in genomic modification aimed at enhancing beta-cell replication. By basing interventions on changes found in human disease and normal aging, this approach will increase the chances that discoveries made can be translated more rapidly into clinically relevant protocols.