STRUCTURE/FUNCTIONS OF HUMAN TEAR LIPOPHILIN

我们发现了一种新的16.5 kDa分子（亲脂蛋白），它是正常人泪液的主要成分。亲脂蛋白分子是由三个胱氨酸二硫键共价连接的异源二聚体。我们的初步序列和结构数据表明，亲脂蛋白是同源的前列腺素，类固醇结合蛋白分泌的速率前列腺。亲脂蛋白的较大亚基也显示出与由乳腺、子宫和肺上皮细胞分泌的某些其他类固醇结合和PLA 2抑制蛋白（乳房珠蛋白、子宫珠蛋白和人CC-10）的强同源性。我们已经组建了一个经验丰富的多学科合作研究小组，以确定亲脂蛋白的结构和功能特性。考虑到其同系物和亲脂蛋白在泪液中的相当大的浓度表明，I可能在角膜和结膜的营养润滑和抗炎需求方面发挥至关重要的作用。具体目标是：1）确定两种亲脂蛋白组分的完整氨基酸序列;确定它们的半胱氨酸如何配对，以及异二聚体是否非共价结合成四聚体。2)从泪腺cDNA文库中克隆每种亲脂蛋白组分;确定是否有任何非眼部组织表达亲脂蛋白相关肽;并鉴定两种亲脂蛋白组分基因的染色体位置。3)通过免疫组织化学方法确定泪腺和其他组织中亲脂蛋白的储存部位。4)建立亲脂蛋白酶联免疫吸附试验（ELISA），并测定正常人泪液中亲脂蛋白的含量。5)检查人泪液亲脂蛋白结合生物学显著脂质（包括类维生素A、选定类固醇激素和磷脂）的能力;鉴别内源性脂质并检查其抑制正常人泪液中发现的II型分泌型磷脂酶A2的能力。这项研究的长期目标是了解亲脂蛋白如何促进角膜和结膜健康，并探索其创造新的诊断和治疗模式的潜力。

We discovered a new 16.5 kDa molecular (lipophilin) that is a prominent component of normal human tears. Lipophilin molecules are heterodimers whole subunits are linked covalently by 3 intramolecular cystine disulfide bonds. Our preliminary sequences and structure data suggest that lipophilin is homologous to prostatein, a steroid-binding protein secrete by the rate prostate gland. The larger subunit of lipophilin also shows strong homology to certain other steroid-binding and PLA2-inhibitory proteins (mammaglobin, uteroglobin and human CC-10) that are secreted by mammary, uterine, and lung epithelial cells. We have assembled an experienced, multi-disciplinary group of co-investigators to determine the structural and functional properties of lipophilin. Both a consideration of its homologues and the considerable concentration of lipophilin in tears suggest that I may play a crucial role with respect to the nutritional lubricating and anti-inflammatory needs of the cornea and conjunctiva. The Specific Aims are: 1) To determine the complete amino acid sequences of both lipophilin components; define how their cysteines pair, and if the heterodimers associate non0covalently into tetramers. 2) To clone each lipophilin component from a lacrimal gland cDNA library; determine if any non-ocular tissues express lipophilin-related peptides; and identify the chromosomal locations of the genes for both lipophilin components. 3) To identify sites of lipophilin storage in the lacrimal gland and other tissues by immunohistochemistry. 4) To establish an ELISA assay for lipophilin and measure its concentration in the tears of normal men and women. 5) To examine the ability of human tear lipophilin to bind biologically significant lipids, including retinoids, selected steroid hormones and phospholipids; to identify endogenous lipids and to examine its ability to inhibit the Type II secretory phospholipase A2 found in normal human tears. The long-term objectives for this research are to learn how lipophilin contributes to corneal and conjuctival health, and to explore its potential for creating new diagnostic and therapeutic modalities.