Molecular Biology of the Kidney-Molecular Analysis of Structure and Function Relationship

我们研究了肾脏的三个主要方面1)肾小球基质和肾小球功能。我们在Alport综合征患者中发现了V型胶原基因α5链突变。这一结果证实了基底膜胶原在肾小球功能中的意义。我们还发现糖化物质可以刺激细胞外基质基因的转录。这种刺激对于糖尿病治疗中常见的肾小球硬化性改变是重要的。2)生物活性物质及其受体的调节。肾小球、肾单位段、肾小动脉均可见TGFb的表达。另一方面，对于TGFb的激活起重要作用的LTBP的mRNA只存在于肾小球和小肾动脉中。我们还开发了一种新的准确的RT-PCR定量方法，这对于像解剖的肾单位段这样的小块组织来说是非常必要的。用该方法显示了PGE_2受体mRNA在肾单位的定位。3)肾脏转运蛋白的克隆和鉴定。我们克隆了一个定位于肾基底膜的集合管水通道，命名为AQP3。我们从转录水平、蛋白质水平和细胞水平揭示了AQP2的多种调控机制。我们在肾脏中克隆了一个大鼠二肽转运体，并发现该转运体可以作为头孢菌素类抗生素的转运体。

We have investigated three major aspects of the kidney.1) Glomerular matrix and glomerular function. We found a mutations of alpha 5 chain of typelV collagen gene in patients with Alport syndrome. This result confirm the significance of basement membrane collagen in glomerular function. We also showed that glycosilated substances stimulates the transcription of extracellular matrix genes. This stimulation is important for the sclorotic changes of glomerulus frequently observed in diabetes meditus.2) Regulation of bioactive substances and their receptors. We showed the presence of TGFb mRNA in glomerulus, all nephron segments, small renal arteiries. On the other hand, mRNA of LTBP,which is important for activation of TGFb, is present only in glomerulus and small renal arteiries. We also developed a new acurate method for quantification of RTPCR which is critically needed for small piece of tissues such as dissected nephron segments. Usin this method we showed the nephron localization of mRNA of PGE2 receptor.3) Cloning and characterization of kidney trnasport proteins. We cloned a kidney collecting duct water channel named AQP3, which is localized at the basolateral membrane. We showed many regulational mechanisms of AQP2 at trnascriptional, protein, and cellular levels. We anso cloned a rat dipeptide transporter in the kidney, and found that this transporter works as a rout for cepharosporin antibiotics.