Dowthwaite G P, Edwards J C, Pitsillides A A
Department of Veterinary Basic Sciences, The Royal Veterinary College, University of London, London, United Kingdom.
J Histochem Cytochem. 1998 May;46(5):641-51. doi: 10.1177/002215549804600509.
We studied the expression of hyaluronan binding proteins (HABPs) during the development of embryonic chick joints, using immunocytochemistry and biotinylated HA. The expression of actin capping proteins and of actin itself was also studied because the cytoskeleton is important in controlling HA-HABP interactions. Three cell surface HABPs were localized in the epiphyseal cartilage, articular fibrocartilage, and interzone that comprise the developing joint. Of these three HABPs, CD44 was associated with the articular fibrocartilages and interzone, whereas RHAMM and the IVd4 epitope were associated with all three tissues. Biotinylated HA was localized to interzone and articular fibrocartilages before cavity formation and within epiphyseal chondrocytes post cavitation. Actin filament bundles were observed at the developing joint line, as was the expression of the actin capping protein moesin. Manipulation of joint cavity development, using oligosaccharides of HA, disrupted joint formation and was associated with decreases in CD44 and actin filament expression as well as decreased hyaluronan synthetic capability. These results suggest that HA is actively bound by CD44 at the developing joint line and that HA-HABP interactions play a major role in the initial separation events occurring during joint formation.
我们利用免疫细胞化学和生物素化透明质酸（HA）研究了胚胎期鸡关节发育过程中透明质酸结合蛋白（HABPs）的表达。由于细胞骨架在控制HA-HABP相互作用中很重要，因此还研究了肌动蛋白封端蛋白和肌动蛋白本身的表达。三种细胞表面HABPs定位于构成发育中关节的骨骺软骨、关节纤维软骨和中间区。在这三种HABPs中，CD44与关节纤维软骨和中间区相关，而RHAMM和IVd4表位与所有三种组织相关。生物素化HA在腔形成前定位于中间区和关节纤维软骨，在腔形成后定位于骨骺软骨细胞内。在发育中的关节线观察到肌动蛋白丝束，肌动蛋白封端蛋白埃兹蛋白的表达也如此。利用HA寡糖操纵关节腔发育会破坏关节形成，并与CD44和肌动蛋白丝表达减少以及透明质酸合成能力降低有关。这些结果表明，在发育中的关节线处，HA被CD44主动结合，并且HA-HABP相互作用在关节形成过程中发生的初始分离事件中起主要作用。
