Increased Methylation Status of SOX-9 Promoter in Human Osteoarthritic Cartilage

INTRODUCTION: Osteoarthritis (OA) is a chronic degenerative joint disorder of high prevalence that remains the leading cause of disability in aged people. A balance between anabolic and catabolic mechanisms maintains extracellular matrix homeostasis in articular cartilage. Among mechanisms to control gene expression, genomic DNA methylation, modification of nucleosome histone tails, and chromosome remodeling are essential contributors to the mechanisms of epigenetic control. Specially, genomic DNA methylation is known as the most fundamental process. A methyl group is added to the 5’ cytosine in a CpG dinucleotide, leading to gene silencing. However, it is not known whether DNA methylation contribute to OA progression. In this study, we examined the methylation status of the promoter region for chondrogenesisor degradation-related genes using MS-PCR and bisulfite sequencing from osteoarthritic and normal cartilages.