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1V型胶原基因α 5链的突变。这一结果证实了基底膜胶原在肾小球功能中的重要性。我们还发现，糖基化物质刺激细胞外基质基因的转录。这种刺激对于糖尿病中经常观察到的肾小球硬化改变是重要的。2）生物活性物质及其受体的调节。我们发现TGF β mRNA在肾小球、所有肾单位节段、小肾动脉中存在。另一方面，对TGF β活化重要的LTBP的mRNA仅存在于肾小球和小肾动脉中。我们还开发了一种新的精确的定量RTPCR方法，这是迫切需要的小块组织，如解剖肾单位节段。利用此方法，我们显示了PGE_2受体mRNA在肾单位的定位。3）肾转运蛋白的克隆和鉴定。我们克隆了一个肾脏集合管水通道命名为AQP3，这是定位于基底外侧膜。我们在转录、蛋白质和细胞水平上揭示了AQP2的多种调节机制。我们还克隆了一个大鼠肾脏二肽转运蛋白，发现该转运蛋白是头孢菌素类抗生素的一个通路。

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.