Growth Versus Differentiation in Human Beta Cells

描述（由申请人提供）：了解成熟内分泌细胞从内分泌前体发育的机制非常重要，因为它可能导致开发用于糖尿病细胞移植疗法的无限β细胞来源。糖尿病研究的一个目标是开发来自人内分泌胰腺的细胞系，所述细胞系可以无限量生长并被诱导沿着分化为β细胞谱系，导致葡萄糖响应性胰岛素分泌。在过去的资助期间，在开发致力于δ或β细胞谱系的细胞系方面取得了成功。这个建议的重点是探索血统承诺的本质。将人胰腺内分泌细胞系转化为δ或β细胞系。该提议的中心假设是，细胞系的分化谱系定型反映了参与成熟内分泌细胞的建立和维持的转录因子表达的差异。 最初，bHLH转录因子NeuroD1抑制生长抑素启动子活性的δ细胞系，导致部分开关的β细胞谱系的机制，将进行研究。将使用逆转录病毒载体介导的基因转移到人胰腺内分泌细胞系中来研究已被鉴定为参与δ细胞与β细胞谱系定型的候选物的其他转录因子。将使用DNA微阵列技术确定在δ细胞系与β细胞系中差异表达的基因以及在b细胞发育中重要的转录因子下游的基因。最后，将进行遗传筛选以分离上调胰岛素启动子活性的基因。

DESCRIPTION (provided by applicant): Understanding the mechanism by which mature endocrine cells develop from endocrine precursors is of great importance as it could lead to the development of an unlimited source of beta cells for cell transplantation therapies for diabetes. A goal of diabetes research has been to develop cell lines from the human endocrine pancreas that can be grown in unlimited quantities and induced to differentiate along the beta cell lineage resulting in glucose-responsive insulin secretion. During the past funding period, success was achieved in developing cell lines that are committed to either the delta or beta cell lineages. This proposal is focused on exploring the nature of that lineage commitment. of human pancreatic endocrine cell lines to either the delta or beta cell lineages. The central hypothesis of this proposal is that the differential lineage commitment of the cell lines reflects differences in the expression of transcription factors that are involved in the establishment and maintenance of mature endocrine cells. Initially, the mechanism by which the bHLH transcription factor NeuroD1 acts to repress somatostatin promoter activity in a delta cell line, resulting in a partial switch to the beta cell lineage, will be studied. Other transcription factors that have been identified as candidates for being involved in delta versus beta cell lineage commitment will be studied using retroviral vector-mediated gene transfer into human pancreatic endocrine cell lines. Genes that are differentially expressed in delta versus beta cell lines and that are downstream of transcription factors that are important in b-cell development will be ascertained using DNA microarray technology. Finally, a genetic screen will be undertaken to isolate genes that upregulate insulin promoter activity.