HNF1A in human endocrine cell development and function

糖尿病是一种复杂的疾病，有三种主要亚型，I型，II型和单基因。I型是一种自身免疫性疾病，其特征在于胰岛素分泌β细胞的损失。II型是代谢紊乱，其特征是胰岛素反应性差，最终导致β细胞衰竭和丢失。单基因形式是由在β细胞发育和/或功能中通常重要的许多基因中的突变引起的。这项提案将集中在HNF 1A的研究上，HNF 1A是一种转录因子，突变时会导致单基因糖尿病的最常见原因。此外，在GWAS研究中，HNF 1A与I型和II型糖尿病有关。HNF 1A缺陷的小鼠模型是可用的，但不幸的是不能适当地模拟人类疾病。因此，使用人体模型系统是重要的。我们将使用人类多能干细胞模型来研究HNF 1A在内分泌细胞发育和功能中的作用，利用基于CRISPR-Cas9的基因组工程来产生等基因突变系。存在稳健的体外分化方案，并将用于在人干细胞模型中产生β细胞。在初步研究中，我们发现了人类特异性HNF 1A靶点，这些靶点已在来自因HNF 1A突变而患有单基因糖尿病的个体的数据集中得到验证。我们还在HNF 1A突变干细胞衍生的β细胞中发现了代谢功能的表型，提供了HNF 1A与II型糖尿病和可能的I型糖尿病之间的潜在联系。最后，HNF 1A的人类特异性靶点之一是一个长的非编码RNA，当在干细胞中缺失时，它模拟了HNF 1A突变体中的一些代谢表型。这些研究将有助于确定HNF 1A在胰腺内分泌细胞中的发育和功能要求，并有可能直接影响不仅罕见的单基因型糖尿病，而且I型和II型糖尿病的治疗。

Diabetes is a complex disorder with three main subtypes, type I, type II and monogenic. Type I is an autoimmune disorder characterized by loss of the insulin secreting beta cell. Type II is metabolic disorder characterized by poor insulin responsiveness and eventual beta cell exhaustion and loss. Monogenic forms are caused by mutations in a number of genes that are generally important in beta cell development and/or function. This proposal will focus on the study on HNF1A, a transcription factor that when mutated leads to the most common cause on monogenic diabetes. In addition, HNF1A has been linked to both type I and type II diabetes in GWAS studies. Mouse models of HNF1A deficiency are available, but unfortunately do not appropriately mimic the human disease. Therefore, use of a human model system is important. We will use the human pluripotent stem cell model to study the role of HNF1A in both endocrine cell development and function, utilizing CRISPR-Cas9 based genome engineering to generate isogenic mutant lines. Robust in vitro differentiation protocols exist and will be used to generate beta cells in the human stem cell model. In preliminary studies, we have uncovered human specific HNF1A targets that have been validated in a dataset from an individual with monogenic diabetes due to a HNF1A mutation. We have also discovered phenotypes in metabolic functions in HNF1A mutant stem cell derived beta cells, offering a potential link between the association of HNF1A with type II and possibly type I diabetes. Lastly, one of the human specific targets of HNF1A is a long non-coding RNA that when deleted in stem cells, mimics some of the metabolic phenotypes seen in the HNF1A mutants. These studies will help define the developmental and functional requirements of HNF1A in pancreatic endocrine cells and have the potential to directly impact the treatment of not only rare monogenic forms of diabetes but also type I and type II diabetes.