Interaction of lumican with aggrecan in the aging human sclera
Interaction of lumican with aggrecan in the aging human sclera
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DOI：
10.1167/iovs.04-0496
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发表时间：
2004-11-01
影响因子：
4.4
通讯作者：
Rada, AAS
中科院分区：
文献类型：
--
作者：
Dunlevy, JR;Rada, AAS
目的。Lumcan是一种硫酸角蛋白多糖，最初存在于角膜中，但存在于各种结缔组织中，推测它调节胶原纤维的形成和组织。方法采用免疫印迹分析、免疫组织化学和免疫亲和层析等方法，从6~89岁的人体供体组织提取液中检测和纯化LUMICA核心蛋白。用软骨素酶ABC、角聚糖酶-I和-II和/或内切-β-半乳糖苷酶处理鲁米肯，以确定鲁米肯核心蛋白的糖基化程度。结果：鲁米肯以70-80 kDa的核心蛋白形式存在于人的巩膜中，带有短的未硫化的乳糖胺聚糖侧链。此外，在Western blotts上，可以明显地看到一个更大的200 kDa的物种，它在免疫学上与鲁米肯有关。随着年龄的增长，这种高分子物质在巩膜提取液中的含量增加。该复合体在未还原的样品中含量最丰富，约三分之二的70-80 kDa的鲁米肯核心蛋白在巩膜提取液还原时从复合体中释放出来。对>；200 kDa的鲁米肯免疫纯化复合体的进一步鉴定表明，聚集素(软骨蛋白多糖)与鲁米肯是共价结合的。结论：巩膜外基质中存在可还原和不可伸缩的鲁米肯-聚集素相互作用，并导致形成随年龄增长的高分子量复合体。这些结果是第一个证明LUMICAN-AGGRECAN相互作用的报告，并表明它们可能在与年龄相关的巩膜细胞外基质改变中发挥作用。
PURPOSE. Lumican is a keratan sulfate proteoglycan originally identified in cornea, but present in a variety of connective tissues where it presumably regulates collagen fibril formation and organization. The present study was designed to describe the chemical nature of lumican core protein in the aging human sclera.METHODS. Western blot analyses, immunohistochemistry, and immunoaffinity chromatography were used to detect and purify the lumican core protein from tissue extracts from human donors 6 to 89 years of age. Treatment of lumican with chondroitinase ABC, keratanase-I and -II, and/or endo-beta-galactosidase was used to determine the degree of glycosylation of the lumican core protein.RESULTS. Lumican was present in the human sclera as a 70- to 80-kDa core protein with short unsulfated lactosaminoglycan side chains. In addition, on Western blots, a larger >200-kDa species was apparent that was immunologically related to lumican. This high-molecular-weight material increased in scleral extracts with increasing age. The complex was most abundant in unreduced samples, and approximately two thirds of the 70- to 80-kDa lumican core protein was released from the complex on reduction of the scleral extract. Further characterization of the >200-kDa lumican-immunopurified complex indicated that aggrecan (the cartilage proteoglycan) was covalently associated with lumican.CONCLUSIONS. Reducible and nonteducible lumican-aggrecan interactions occur in the scleral extracellular matrix and result in the formation of high-molecular-weight complexes that increase with age. These results represent the first report demonstrating lumican-aggrecan interactions and suggest they may play a role in age-related scleral extracellular matrix changes.