Internalization of the hyaluronan receptor CD44 by chondrocytes
Internalization of the hyaluronan receptor CD44 by chondrocytes
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DOI：
10.1006/excr.1999.4641
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发表时间：
1999-11-01
影响因子：
3.7
通讯作者：
Knudson, CB
中科院分区：
文献类型：
--
作者：
Aguiar, DJ;Knudson, W;Knudson, CB
软骨细胞表达CD 44作为基质大分子透明质酸的主要受体。透明质酸负责软骨内蛋白聚糖的保留和组织，并且透明质酸-软骨细胞相互作用对于软骨基质的组装和维持是重要的。用牛关节软骨细胞研究了CD 44的内吞和周转以及受体占有率对这种周转的影响。基质完整的软骨细胞在4小时内表现出约6%的细胞表面CD 44内化。用链霉菌透明质酸酶处理以去除内源性细胞周基质，在4 h时将细胞表面CD 44的内化增加至约20%。这种营业额可以部分抑制外源性透明质酸，这些基质耗尽的软骨细胞。细胞表面生物素标记的CD 44被软骨细胞内化，并且这种内化在透明质酸存在下降低。内化的CD 44和荧光素标记的透明质酸在胞内囊泡中的共定位与先前的结果相关，该结果是通过酸性水解酶降解透明质酸的受体介导的内吞途径。两者合计，我们的研究结果表明，CD 44是内化的软骨细胞和CD 44的营业额是由透明质酸占用调制。(C)北京：科学出版社.
Chondrocytes express CD44 as a primary receptor for the matrix macromolecule hyaluronan. Hyaluronan is responsible for the retention and organization of proteoglycan within cartilage, and hyaluronan-chondrocyte interactions are important for the assembly and maintenance of the cartilage matrix. Bovine articular chondrocytes were used to study the endocytosis and turnover of CD44 and the effects of receptor occupancy on this turnover. Matrix-intact chondrocytes exhibit approximately a 6% internalization of cell surface CD44 by 4 h. Treatment with Streptomyces hyaluronidase to remove endogenous pericellular matrix increased internalization to approximately 20% of cell surface CD44 at 4 h. This turnover could be partially inhibited by the addition of exogenous hyaluronan to these matrix-depleted chondrocytes. Cell surface biotin-labeled CD44 was internalized by chondrocytes and this internalization was decreased in the presence of hyaluronan. Colocalization of internalized CD44 and fluorescein-labeled hyaluronan in intracellular vesicles correlates with the previous results of receptor-mediated endocytosis pathway for the degradation of hyaluronan by acid hydrolases. Taken together, our results indicate that CD44 is internalized by chondrocytes and that CD44 turnover is modulated by occupancy with hyaluronan. (C) 1999 Academic Press.