Department of Dermatology, University of Michigan, Ann Arbor, MI, USA.
Sci Rep. 2013;3:2422. doi: 10.1038/srep02422.
Proteoglycans, a family of glycosaminoglycan (GAG) conjugated proteins, are important constituents of human skin connective tissue (dermis) and are essential for maintaining mechanical strength of the skin. Age-related alterations of dermal proteoglycans have not been fully elucidated. We quantified transcripts of 20 known interstitial proteoglycans in human skin and found that decorin was the most highly expressed. Decorin was predominantly produced by dermal fibroblasts. Decorin was localized in dermal extracellular matrix with GAG bound to type I collagen fibrils. Analysis of decorin extracted from young (21-30 years) and aged (>80 years) sun-protected human buttock skin revealed that decorin molecular size in aged skin is significantly smaller than in young skin. The average size of decorin protein did not alter, indicating size of GAG chain is reduced in aged, compared to young skin. This age-dependent alteration of decorin GAG may contribute to skin fragility of elderly people.
蛋白聚糖是糖胺聚糖（GAG）与蛋白质的结合物家族，是人体皮肤结缔组织（真皮）的重要组成部分，对于维持皮肤的机械强度至关重要。真皮蛋白聚糖的年龄相关性改变尚未完全阐明。我们定量分析了 20 种已知的人皮肤间质蛋白聚糖的转录本，发现核心蛋白聚糖的表达量最高。核心蛋白聚糖主要由真皮成纤维细胞产生。核心蛋白聚糖定位于真皮细胞外基质中，其 GAG 与 I 型胶原纤维结合。从小（21-30 岁）和老年（>80 岁）人臀部防晒皮肤中提取的核心蛋白聚糖分析表明，老年皮肤中的核心蛋白聚糖分子大小明显小于年轻皮肤。核心蛋白聚糖蛋白的平均大小没有改变，这表明与年轻皮肤相比，老年皮肤中的 GAG 链的大小减小。核心蛋白聚糖 GAG 的这种年龄依赖性改变可能导致老年人皮肤脆弱。
