The proteome of normal human sclera

The sclera provides an opaque protective coat for five-sixths of the surface of the human eye. A detailed investigation of the proteome of the normal human sclera may provide insights into the biology and pathophysiology of the sclera. We conducted an in-depth proteomic analysis of sclera from five adults. Proteins were fractionated using SDS-PAGE. After in-gel digestion, peptides were analyzed using LC-MS/MS on an Orbitrap Elite mass spectrometer. We identified 1952 non-redundant proteins in the human sclera, including 18 different collagen protein chains (types 1, II, III, IV, VI, VIII, X, XII, XIV, XV, XVI, XVIII), proteins of the small leucine-rich proteoglycan family (decorin, biglycan, lumican, keratocan, prolargin, fibromodulin, and mimecan), non-collagenous glycoproteins (fibronectin, vitronectin, and laminin), extracellular matrix proteins (thrombospondins 1, 2, 3, 4, dystroglycan, and transgelins 1, 2, 3), matrix metalloproteinases 3 and 14, matrix metalloproteinase inhibitors 1, 2, and 3, and integrins alpha-V, alpha-1, alpha-2, beta-1, beta-2, and beta-5.巩膜（sclera）是覆盖人类眼球表面六分之五区域的不透明保护性外膜。对正常人类巩膜蛋白质组的深入研究，可为巩膜的生物学特性与病理生理学机制提供新见解。本研究对5名成人的巩膜组织开展了深度蛋白质组学分析：采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）对蛋白质进行分级分离，经胶内酶解后，利用轨道阱Elite（Orbitrap Elite）质谱仪通过液相色谱-串联质谱（LC-MS/MS）对肽段进行分析。本研究在人类巩膜中共鉴定出1952种非冗余蛋白质，涵盖18种不同的胶原蛋白链（1型、II型、III型、IV型、VI型、VIII型、X型、XII型、XIV型、XV型、XVI型、XVIII型）、富含亮氨酸的小分子蛋白聚糖家族蛋白（decorin、biglycan、lumican、keratocan、prolargin、fibromodulin及mimecan）、非胶原蛋白糖蛋白（纤连蛋白、玻连蛋白及层粘连蛋白）、细胞外基质蛋白（血小板反应蛋白1、2、3、4、肌营养不良蛋白聚糖，以及转胶蛋白1、2、3）、基质金属蛋白酶3与14、基质金属蛋白酶抑制剂1、2、3，以及整合素α-V、α-1、α-2、β-1、β-2、β-5。