treatment using adenovirus vector

我们利用重组腺病毒研究了胰岛素刺激3T3-L1脂肪细胞葡萄糖转运的信号转导。PI3-激酶的显性负性表达抑制了胰岛素刺激的葡萄糖转运活性和GLUT4的转位，表明PI3-激酶的激活在胰岛素刺激的葡萄糖转运中起着重要作用。然而，在PI3K活性和葡萄糖转运活性之间观察到了差异，这表明另一条不同的途径(S)参与了胰岛素刺激的葡萄糖转运的内在活性。与PI3-激酶的参与相反，ras的激活不参与胰岛素刺激的葡萄糖转运，因为显性负性RAS的过表达不影响胰岛素刺激的葡萄糖转运。我们还利用重组腺病毒研究了胰岛素分泌机制。GK大鼠胰岛线粒体FAD连接的甘油-3-磷酸脱氢酶(MGPDH)活性降低。由于胰岛素分泌缺陷被归因于mGPDH活性的降低，我们通过使用腺病毒载体过表达mGPDH来纠正mGPDH活性的降低。然而，胰岛素分泌缺陷并未得到纠正，这表明mGPDH活性降低不是GK大鼠胰岛素分泌缺陷的原因。利用定位克隆的方法，我们克隆了一个与Wolfram综合征相关的新基因，该综合征以非免疫性胰岛素依赖型糖尿病和视神经萎缩为特征。该基因命名为WFS1，在胰岛β细胞和神经细胞的存活过程中发挥着重要作用。我们还在3例日本婴儿期持续性高胰岛素低血糖患者中发现了磺脲受体基因突变，并阐明了胰岛素分泌受损的分子机制，特别是ADP和ATP可能与磺脲受体结合的部位。

We have studied insulin signaling toward stimulation of glucose transport in 3T3-L1 adipocytes using recombinant adenovirus. Expression of dominant negative p85 submit of PI3-kinase inhibited insulin-stimulated glucose transeport activity and GLUT4 translocation, indicating an important role of PI3-kinase activation in insulin-stimulated glucose transport. However, a discrepancy was observed between PI3-kinase activity and glucose transport activity, suggesting a possibility that a different pathway(s) is involved in insulin-stimulated intrinsic activity of glucose transport. In contrast to the involvement of PI3-kinase, ras activation is not involeved in insulin-stimulated glucose transeport, since overexpression of dominant negative Ras did not affect insulin-stimulated glucose transport.We have also studied insulin secretion mechanism using recombinant adenovirus. Mitochondrial FAD-linked glycerol-3-phosphate dehydrogenase (mGPDH) was decreased in pancreatic islets of GK rats which show defects in insulin serection. Since defects in insulin secretion had been ascribed to decreased mGPDH activity, we corrected the decreased mGPDH activity by overexpressing mGPDH using adenovirus vector. However, defects in insulin secretion was not corrected, indicating decreased mGPDH activity is not responsible for insulin secretion defects in GK rats. Employing positional cloning method, we have cloned a novel gene responsible for Wolfram syndrome characterized by non-immune insulin dependent diabetes mellitus and optic atrophy. This gene, designated WFS1, must have an important role in survival of pancreatic beta cells and neuronal cells. We also found mutations in sulfonylurea receptor gene in three Japanese patients with persistent hyperinsulinemic hypoglycemia of infancy and elucidated the molecular mechanism for defests in insulin secretion, especially a possible binding site of ADP and ATP for sulfonylurea receptor.