Study of a novel autoantigen related to autoimmune enteropathy with renal tubular dysfunction

一种与肾小管功能障碍自身免疫性肠病相关的新型自身抗原的研究

基本信息

批准号：
12470162
负责人：
KOBAYASHI Kunihiko
金额：
$ 8.9万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

Autoimmune enteropathy is a rare desease characterized by circulating autoantibody against epithelial cells of the intestine. Some cases are inherited by an X-linked manner and named immunedysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX). The aim of our study is to identity the target of the autoantibody and to clarify the biological functions of the antigen.For this purpose, we screened λgt11 cDNA expression library from human duodenum with the serum from an IPEX patient, and identified a cDNA encoding a novel protein consisting of 552 amino acids. The protein named autoimmune, enteropathy-related 75 kDa antigen (AIE-75) predominantly distributed to the brush border in the small intestine and proximal renal tubulus. AIE-75 gene was mapped to chromosome 11p14.3. In collaboration with C. Petit of the Pasteur Institute, we demonstrated that AIE-75 also distributed to the epithelial cells in the inner ear and that mutation of the gene caused a hereditary deafness, Usher syndrome type 1C. This suggests that AIE-75 plays a biologically significant rolls in not only the small intestine and kidney but also in the inner ear.AIE-75 contains three PDZ domains, suggesting that the protein functions as a linker protein. Using yeast two-hybrid screening, we identified a novel protein homologous to a tumor suppressor, MCC, and named MCC-2. In addition, overexpression of AIE-75 in a colon cancer cell line, SW480, which lacks AIE-75 resulted in G2/M arrest. These findings suggest that AIE-75 is involved in the regulation of cell cycle. Recently, a forkhead/winged helix transcription regulator, FOXP3, has been identified as a causative gene of IPEX. We reported two novel mutation of FOXP3 in Japanese patients with IPEX and suggested that Ile363 is necessary for the normal function of FOXP3.

自身免疫性肠病是一种罕见的溶液，其特征是对肠上皮细胞的自身抗体循环。某些情况是通过X连锁方式遗传的，并命名为免疫分节调节，多内分腺疗法，肠病，X连锁综合征（IPEX）。我们研究的目的是识别自身抗体的靶标并阐明抗原的生物学功能。为此，我们用IPEX患者的血清筛选了来自人类的血清的λgt11cDNA表达式，并确定了编码由552氨基酸组成的新型蛋白质的cDNA。该蛋白质称为自身免疫性，肠病相关的75 kDa抗原（AIE-75），主要分布在小肠和近端肾结通的刷子边框上。 AIE-75基因被映射到11p14.3染色体。与巴斯德研究所的C. petit合作，我们证明了AIE-75还分布在内耳中的上皮细胞上，并且基因的突变引起了遗传性死亡，usher综合征1c型。这表明AIE-75不仅在小肠和肾脏，而且在内耳中都具有生物学意义。使用酵母双杂交筛选，我们确定了一种与肿瘤抑制剂MCC同源的新型蛋白质，并命名为MCC-2。此外，缺乏AIE-75的结肠癌细胞系中AIE-75的过表达导致G2/m停滞。这些发现表明AIE-75参与细胞周期的调节。最近，叉头/有翼的螺旋转录调节器Foxp3被确定为IPEX的灾难性基因。我们报道了日本IPEX患者的两个新型FOXP3突变，并建议ILE363对于FOXP3的正常功能是必需的。