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Mechanism of Differentiation of Pancreatic β Cells

胰腺β细胞的分化机制

基本信息

批准号：
11470230
负责人：
KOJIMA Itaru
金额：
$ 10.24万
依托单位：
Gunma University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11470230/
关键词：
pancreatic β cells insulin differentiation transcription factor activin A HGF

项目摘要

To elucidate the molecular mechanism for differentiation of pancreatic β cells, we studied the changes in the expression of various transcription factors during differentiation of pancreatic AR42J cells to insulin-producing cells. These cells are amylase-secreting tumor cells and differentiate to insulin-secreting cells in response to activin A and hepatocyte growth factor (HGF). We studied the changes in the expression of variou transcription factors expressed in pancreatic islets by RT-PCR.Among various transcription factors studied, expression of Pax4 and neurogenin3 (ngn3) was markedly increased during the differentiation. Thus, the expression of Pax4 and ngn3 was not detectable in naive AR42J cells but induced after the treatment with activin A and HGF.It was activin A but not HGF that induced the expression of Pax4 and ngn3. To assess the functional significance of these transcription factors, we introduced cDNA for Pax4 or ngn3 in naive AR42J cells and examined the changes in morphology and expression of various differentiation markers. We also studied the effect of introducing antisense cDNA.When Pax 4 was introduced into naive AR42J cells, nothing happened. Furthermore, introduction of antisense cDNA did not affect the ddiferentiation induced by activin A and HGF.In contrast, transfection of Pax4 to naive AR42J cells induced morphological changes. Thus, cells extended neurite-like processes, Also, expression of pancreatic polypeptide was induced by transfection of ngn3. Additionally, reduction of ngn3 expression resulted in the inhibition of differentation of AR42J into insulin-secreting cells. We conclude that induction of ngn3 expression is critical in differentiation of AR42J cells by activin A.

为了阐明胰腺β细胞分化的分子机制，我们研究了胰腺AR42J细胞向胰岛素分泌细胞分化过程中各种转录因子表达的变化。这些细胞是分泌淀粉酶的肿瘤细胞，在激活素A和肝细胞生长因子(HGF)的反应下分化为胰岛素分泌细胞。我们用RT-PCR法研究了各种转录因子在胰岛中表达的变化。在所研究的各种转录因子中，Pax4和NGN3的表达在分化过程中明显增加。因此，在幼稚的AR42J细胞中未检测到Pax4和NGN3的表达，但经激活素A和HGF处理后，Pax4和NGN3的表达被诱导。为了评估这些转录因子的功能意义，我们在NAIVE AR42J细胞中引入了Pax4或NGN3的cDNA，并检测了各种分化标志物的形态和表达的变化。我们还研究了反义cDNA的导入效果。将Pax 4导入未成熟的AR42J细胞，未见任何反应。此外，反义c DNA的引入不影响激活素A和hGF诱导的分化。相反，将Pax4转染入未分化的AR42J细胞后，细胞形态发生改变。因此，NGN3基因可以延长细胞突起的突起，并诱导胰多肽的表达。此外，下调NGN3的表达可抑制AR42J向胰岛素分泌细胞的分化。我们认为，在激活素A诱导AR42J细胞分化过程中，NGN3的表达起关键作用。