Funderburgh J L, Hevelone N D, Roth M R, Funderburgh M L, Rodrigues M R, Nirankari V S, Conrad G W
Division of Biology, Kansas State University, Manhattan 66506-4901, USA.
Invest Ophthalmol Vis Sci. 1998 Sep;39(10):1957-64.
Corneas with scars and certain chronic pathologic conditions contain highly sulfated dermatan sulfate, but little is known of the core proteins that carry these atypical glycosaminoglycans. In this study the proteoglycan proteins attached to dermatan sulfate in normal and pathologic human corneas were examined to identify primary genes involved in the pathobiology of corneal scarring.
Proteoglycans from human corneas with chronic edema, bullous keratopathy, and keratoconus and from normal corneas were analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), quantitative immunoblotting, and immunohistology with peptide antibodies to decorin and biglycan.
Proteoglycans from pathologic corneas exhibit increased size heterogeneity and binding of the cationic dye alcian blue compared with those in normal corneas. Decorin and biglycan extracted from normal and diseased corneas exhibited similar molecular size distribution patterns. In approximately half of the pathologic corneas, the level of biglycan was elevated an average of seven times above normal, and decorin was elevated approximately three times above normal. The increases were associated with highly charged molecular forms of decorin and biglycan, indicating modification of the proteins with dermatan sulfate chains of increased sulfation. Immunostaining of corneal sections showed an abnormal stromal localization of biglycan in pathologic corneas.
The increased dermatan sulfate associated with chronic corneal pathologic conditions results from stromal accumulation of decorin and particularly of biglycan in the affected corneas. These proteins bear dermatan sulfate chains with increased sulfation compared with normal stromal proteoglycans.
有瘢痕和某些慢性病理状况的角膜含有高度硫酸化的硫酸皮肤素，但对于携带这些非典型糖胺聚糖的核心蛋白了解甚少。在本研究中，对正常和病理性人角膜中与硫酸皮肤素相连的蛋白聚糖蛋白进行检测，以确定参与角膜瘢痕形成病理生物学过程的主要基因。
使用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）、定量免疫印迹法以及用针对核心蛋白聚糖和双糖链蛋白聚糖的肽抗体进行免疫组织学分析，对患有慢性水肿、大泡性角膜病变和圆锥角膜的人角膜以及正常角膜中的蛋白聚糖进行分析。
与正常角膜中的蛋白聚糖相比，病理性角膜中的蛋白聚糖表现出更大的大小异质性以及与阳离子染料阿尔辛蓝的结合。从正常和患病角膜中提取的核心蛋白聚糖和双糖链蛋白聚糖表现出相似的分子大小分布模式。在大约一半的病理性角膜中，双糖链蛋白聚糖的水平平均比正常水平高出七倍，核心蛋白聚糖则比正常水平高出约三倍。这些增加与核心蛋白聚糖和双糖链蛋白聚糖的高电荷分子形式相关，表明这些蛋白质被硫酸化增加的硫酸皮肤素链修饰。角膜切片的免疫染色显示病理性角膜中双糖链蛋白聚糖在基质中的定位异常。
与慢性角膜病理状况相关的硫酸皮肤素增加是由于在受影响的角膜中核心蛋白聚糖尤其是双糖链蛋白聚糖在基质中的积累。与正常基质蛋白聚糖相比，这些蛋白质带有硫酸化增加的硫酸皮肤素链。
