Functional genomics for renal diseases

由于终末期肾病导致的血液透析在日本是一个主要的社会和经济问题，因为目前约有17万患者接受治疗，并且该人数每年约增加13，000人。而且因为治疗透析病人的医疗费用已经上升到每年一万多亿美元，约占日本医疗费用总额的百分之四。慢性肾小球肾炎和糖尿病肾病是两种主要的基础疾病，约占肾功能不全患者总数的80%。然而，它们的确切机制在分子水平上仍然未知，因此没有有效的治疗方法。我们实验室正在进行的项目的目的是1）阐明肾脏疾病（如慢性肾小球肾炎和糖尿病肾病）的分子发病机制，2）开发新的治疗方法来预防或延缓肾脏疾病的进展。 关于我们 血管细胞在维持肾小球的结构和功能以及在肾小球疾病的发病机制中起重要作用。肾小球系膜细胞的增殖和细胞外系膜基质的积累是导致患有各种肾小球疾病（例如慢性肾小球肾炎和糖尿病肾病，终末期肾衰竭的两个主要原因）的患者进展为肾小球硬化的主要事件。本研究的目的是：1）对培养的人肾小球系膜细胞中表达的基因进行分子生物学定量; 2）鉴定肾小球系膜细胞中表达的特异性基因。为了获得肾小球系膜细胞表达基因的定量信息，我们采用了一个人肾小球系膜细胞3 ′-定向区域cDNA文库。用这种方法，我们可以避免可变的克隆效率反映cDNA的大小。我们随机选择了近2000个克隆，通过PCR扩增它们的cDNA部分，并确定它们的cDNA序列。由于3 '区的序列是独特的，因此约150-300个核苷酸的测序数据足以表征该基因。相同序列的冗余代表细胞中相应转录物的丰度。系膜细胞的“表达谱”与其他文库的表达谱明显不同，证实了不同细胞和器官的“表达谱”具有特异性。另外，我们还鉴定了5个在系膜细胞中特异表达的未知基因，命名为megsin、meg-1、meg-2、meg-3和meg-4，Megsin是丝氨酸蛋白酶抑制剂（serine protease inhibitor，serpin）超家族的新成员。我们前期的研究有力地表明了megsin在人类肾小球疾病发病机制中的作用，但其确切的生物学意义尚不清楚。我们在转基因小鼠中生产人类巨噬细胞。megsin的过度表达导致进行性系膜基质扩张和系膜细胞数量增加。因此，Megsin对系膜功能具有生物学相关影响。少

Hemodialysis due to end-stage renal diseases is a major social and economic problem in Japan because about 170,000 patients are treated at present, and the number has been increasing by about 13,000 every year. and because the medical expenses for the treatment of dialysis patients has risen up to more than a trillion U.S.dollars per year which takes up approximately four percent of total medical expenses in Japan. Chronic glomerulonephritis and diabetic nephropathy are two major underlying diseases which account for about 80% of the total number of patients with renal insufficiency. However, their exact mechanisms are still unknown at the molecular levels and therefore there is no effective therapy. The purposes of the projects in progress in our laboratory is 1) to elucidate the molecular pathogenesis of renal diseases, such as chronic glomerulonephritis and diabetic nephropathy, and 2) to develop novel therapeutic approaches to prevent or retard the progression of renal diseases.Mes … More angial cells play an important role in maintaining a structure and function of the glomerulus and in the pathogenesis of glomerular diseases. The proliferation of mesangial cells and the accumulation of extracellular mesangial matrix are primary events leading to the progression to glomerulosclerosis in patients with a variety of glomerular disorders such as chronic glomerulonephritis and diabetic nephropathy, two major causes of end-stage renal failure. The purposes of the present study were 1) to perform a molecular biological quantification of genes expressed in cultured human mesangial cells and 2) to identify specific genes expressed in mesangial cells. To obtain quantitative information of expressed genes in mesangial cells, we employed a 3'-directed regional cDNA library from human mesangial cells. With this approach, we can avoid variable cloning efficiencies reflecting the size of cDNA.we randomly chose almost 2000 transformant colonies, amplified their cDNA moieties by PCR and determined their cDNA sequences. Since the sequences at the 3'-region are unique, sequencing data from about 150-300 nucleotides were sufficient to characterize the gene. Redundancy of the same sequence represents the abundance of corresponding transcript in cells. The "expression profiles" in mesangial cells were apparently different from those obtained from other libraries, which confirmed specificity of "expression profiles" in different cells and organs. And, we identified 5 unknown genes, termed megsin, meg-1, -2, -3, and -4, specifically expressed in mesangial cells.Megsin is a new member of the serine protease inhibitor (serpin) superfamily. Our previous studies strongly suggest the role of megsin in the pathogenesis of human glomerular diseases, but its exact biological significance has not been clear. We produce human megsin transgenic mice. Overexpression of megsin leads to progressive mesangial matrix expansion and to an increase in the number of mesangial cells. Megsin has thus a biologically relevant influence on mesangial function. Less