Functional analysis and genomic mapping of corneal epithelium-specific genes and detection of disease-related genes among ocular surface disorders.

我们从角膜上皮cDNA文库中克隆了3个新基因：组织蛋白酶V、尿斑蛋白1b和钙依赖性氯离子通道（CACL 2）。组织蛋白酶V是一种在弱酸性条件下工作的半胱氨酸蛋白酶。新克隆的Uroplakin 1b是以前报道的3'端序列的一种亚型。CACL 2定位于人类染色体1 p32，在角膜上皮中的表达水平比其他氯离子通道高100倍，这表明它对角膜透明性是必不可少的。羊膜上培养的角膜上皮细胞与正常角膜上皮细胞基因表达的DNA芯片检测显示，IL-6、IL-13、IL-4表达下调，IGF结合蛋白表达上调，比较Sjogren综合征患者和正常志愿者结膜上皮的基因表达，还发现Sjogren综合征患者中细胞角蛋白6、16、SPRR 2A、激肽释放酶7、IL-6、IL-6、双调蛋白、HLA-DR、防御素β 2、纤连蛋白和c-fos转录因子的上调。这些事实表明，由于结膜上皮细胞的严重干燥和快速更新，这种疾病中的结膜上皮细胞具有角化和细胞增殖的趋势。此外，干扰素γ，它可以分泌在泪液中，可以诱导表达的α，HLA-DR和防御素β 2在这种疾病。

We have cloned 3 novel genes from the CDNA library of corneal epithelium : cathepsin V, uroplakin 1b and calcium-dependent chloride channel (CACL2). Cathepsin V proved to be a kind of cysteine protease working on weak acid condition. Uroplakin 1b, newly cloned, is an isoform of that reported previously in the 3' end sequence. CACL2, mapped to 1p32 of human chromosome, was expressed in corneal epithelium at a 100 x higher level than the other chloride channels, suggesting that it is essential for corneal transparency.DNA chip comparison of peripheral blood T lymphocyte gene expression between chronic phase S-J syndrome patients and normal volunteers revealed up-regulation of HMG-1, calmodulin, and down-regulation of ferritin L chain and 56K autoantigen annexin X1.DNA chip measurement of gene expression between corneal epithelium cultivated on amniotic membrane and normal corneal epithelium in vivo revealed down-regulation of IL-6, IL-13, IL-4, and up-regulation of IGF-binding protein, emmprin and CD27 ligand.Comparison of gene expression on conjunctival epithelium between Sjogren's syndrome patients and normal volunteers also revealed up-regulation of cytokeratin 6, 16, SPRR2A, kallikrein7, IL-6, MIG, amphiregulin, HLA-DR, defensin beta 2, fibronectin and c-fos transcription factor in Sjogren's syndrome. These facts suggest that conjunctival epithelial cells in this disease have a tendency toward keratinization and cell proliferation, due to severe dryness and fast turnover of conjunctival epithelial cells. Also, interferon gamma, which may be secreted in tear fluid, may induce expression of MIG, HLA-DR and defensin beta 2 in this disease.