Title : Role of DNA methylation on 15-lipoxygenase-1 gene expression in osteoarthritis
Abstract:
Objective and design. Osteoarthritis (OA) is the most prevalent type of arthritis and a major contributor to physical impairment with a significant financial impact. OA. Pain, stiffness, and a restricted range of motion are the primary signs and symptoms of OA. Genetics, age, obesity, joint damage, and knee malalignment are risk factors for OA. Numerous anti-inflammatory and immunomodulatory lipid mediators are produced by 15-lipoxygenase-1 (15-LOX-1), which has been shown to have protective effects against a number of inflammatory diseases, including OA. The purpose of this study was to assess the expression of 15-LOX-1 in the cartilage of OA patients and normal donors, as well as to ascertain whether DNA methylation controls this expression.
Methods. Cartilage samples were collected from both OA-affected at the time of total knee replacement surgery, and normal knee joints during autopsy. Real-time polymerase chain reaction (PCR) was used to assess the expression of 15-LOX-1. Using 5-Aza-2'-desoxycytidine (5-Aza-dC), a DNA methyltransferase inhibitor, the significance of DNA methylation in 15-LOX-1 expression was evaluated. Using a CpG-free luciferase vector, the impact of CpG methylation on the activity of the 15-LOX-1 promoter was assessed. Pyrosequencing was used to ascertain the 15-LOX-1 promoter's DNA methylation status.
Results. Compared to healthy cartilage, OA showed increased expression of 15-LOX-1. 15-LOX-1 mRNA levels were upregulated in chondrocytes treated with 5-Aza-dc, and 15-LOX-1 promoter activity was downregulated in vitro through methylation. The methylation status of the 15-LOX-1 gene promoter did not differ between cartilage from normal and OA cartilage.
Conclusion. In OA cartilage, there was an increased expression level of 15-LOX-1, which might be related to a healing process. The methylation status of 15-LOX-1's promoter was not linked to its upregulation in OA cartilage, indicating that alternative mechanisms may be at play.
Key words: 15-LOX-1, cartilage, osteoarthritis, chondrocyte, epigenetics, DNA methylation
