Yokota Hiroyuki, Hiramoto Masashi, Okada Hirokazu, Kanno Yoshihiko, Yuri Masatoshi, Morita Shuji, Naitou Masanori, Ichikawa Atsushi, Katoh Masao, Suzuki Hiromichi
Astellas Pharm Inc., 21 Miyukigaoka, Tsukuba-shi 305-8585, Japan.
Mol Cell Proteomics. 2007 Apr;6(4):738-44. doi: 10.1074/mcp.M600336-MCP200. Epub 2007 Jan 21.
To search for biomarkers of IgA nephropathy, protein profiles of urine samples from patients with IgA nephropathy and normal volunteers were compared using two-dimensional DIGE. Most of the 172 spots identified in the urine were serum proteins, and their amounts in IgA nephropathy urine were much higher than those in normal urine; this can be explained as proteinuria caused by glomerular dysfunction. However, only alpha(1)-microglobulin, also one of the major serum proteins, in IgA nephropathy urine was not higher in amount than that in normal urine. We confirmed using ELISA analysis that the amounts of transferrin and albumin in IgA nephropathy and diabetic nephropathy urine were much higher than those in normal urine, whereas the amount of alpha(1)-microglobulin in IgA nephropathy urine was not higher than that in normal urine and was much lower than that in diabetic nephropathy urine. Approximately 50% of alpha(1)-microglobulin forms a complex with IgA in serum. These results suggest that alpha(1)-microglobulin in IgA nephropathy urine is a characteristic protein and might be a biomarker for IgA nephropathy and that alpha(1)-microglobulin might have a relationship with IgA nephropathy pathology.
为了寻找IgA肾病的生物标志物，使用二维差异凝胶电泳（DIGE）比较了IgA肾病患者和正常志愿者尿液样本的蛋白质谱。尿液中鉴定出的172个斑点中的大多数是血清蛋白，它们在IgA肾病尿液中的含量远高于正常尿液中的含量；这可以解释为肾小球功能障碍导致的蛋白尿。然而，IgA肾病尿液中同样作为主要血清蛋白之一的α1-微球蛋白的含量并不高于正常尿液。我们通过酶联免疫吸附测定（ELISA）分析证实，IgA肾病和糖尿病肾病尿液中转铁蛋白和白蛋白的含量远高于正常尿液，而IgA肾病尿液中α1-微球蛋白的含量不高于正常尿液且远低于糖尿病肾病尿液。血清中约50%的α1-微球蛋白与IgA形成复合物。这些结果表明，IgA肾病尿液中的α1-微球蛋白是一种特征性蛋白，可能是IgA肾病的生物标志物，并且α1-微球蛋白可能与IgA肾病的病理过程有关。
