Abnormal expression of chondroitin sulphate N-acetylgalactosaminyltransferase 1 and Hapln-1 in cartilage with Kashin–Beck disease and primary osteoarthritis

PURPOSE: Kashin-Beck disease (KBD) is an endemic degenerative osteoarthritis associated with extracellular matrix degradation. The aim of this investigation was to evaluate the role of targeting genes in the pathogenesis of KBD and primary osteoarthritis (OA) involved in extracellular matrix degradation. METHODS: Agilent 44 K human whole-genome oligonucleotide microarrays were used to detect the gene expression in KBD and OA cartilage. The mRNA and protein expressions of CSGalNAcT-1 and Hapln-1 in chondrocytes were verified by reverse transcription polymerase chain reaction (RT-PCR) and western blot, and their expression in cartilage were verified with immunocytochemical analysis. Meanwhile, CSGalNAcT-1 and Hapln-1 protein levels in the selenium intervention group of KBD with different concentrations (0.25, 0.1and 0.05 μg/ml) were detected by western blot. RESULTS: CSGalNAcT-1 and Hapln-1 were down-regulated in KBD and OA at both mRNA and protein levels, and were increased in Se(Selenium) groups compared to KBD free-Se group. However, Wnt 3a, β-catenin and Runx-2 were up-regulated in OA and KBD at protein levels. Additionally, immunohistochemical staining showed that CSGalNAcT-1 and Hapln-1 were reduced in all zones of KBD and OA articular cartilage, but not significantly reduced in the up zone of OA articular cartilage. CONCLUSIONS: The CSGalNAcT-1 and Hapln-1 were down-regulated in both KBD and OA cartilage. CSGalNAcT-1 may be involved in the damage of articular cartilage of KBD and OA by regulating Hapln-1 in the Wnt/β-catenin signalling pathway. It was indicated that CSGalNAcT-1 and Hapln-1 may play important roles in the pathogenesis of KBD and OA.