The Role of MicroRNAs in the Pathophysiology of Osteoarthritis.

Worldwide, osteoarthritis (OA) is the most common cause of joint pain in older people. Many factors contribute to osteoarthritis' development and progression, including secondary osteoarthritis' underlying causes. It is important to note that osteoarthritis affects all four tissues: cartilage, bone, joint capsule, and articular apparatus. An increasingly prominent area of research in osteoarthritis regulation is microRNAs (miRNAs), a small, single-stranded RNA molecule that controls gene expression in eukaryotes. We aimed to assess and summarize current knowledge about the mechanisms of the action of miRNAs and their clinical significance. Osteoarthritis (OA) is affected by the interaction between miRNAs and inflammatory processes, as well as cartilage metabolism. MiRNAs also influence cartilage cell apoptosis, contributing to the degradation of the cartilage in OA. Studies have shown that miRNAs may have both an inhibitory and promoting effect on osteoporosis progression through their influence on molecular mechanisms. By identifying these regulators, targeted treatments for osteoarthritis may be developed. In addition, microRNA may also serve as a biomarker for osteoarthritis. By using these biomarkers, the disease could be detected faster, and early intervention can be instituted to prevent mobility loss and slow deterioration.

miRNA-146a-5p is upregulated in serum and cartilage samples of patients with osteoarthritis.

INTRODUCTION: Osteoarthritis (OA) is a widely prevalent joint disease leading to motor disability and pain. Appropriate indicators for identifying patients at risk for this progressive disease, identifying molecular events for detecting early phases of the disease, or biomarkers to screen for treatment responses, however, are lacking. Micro RNAs (miRNAs), which play crucial roles in OA, could be potential biomarkers of OA. Because circulating miRNA levels reflect the disease state, they may be useful for OA screening and as diagnostic tools, reducing the need for invasive procedures and minimizing the cost of current diagnostic methods. MATERIALS AND METHODS: The expression levels of 18 microRNAs (let-7e-5p, miR-21-5p, miR-93-5p, miR-101-3p, miR-103a-3p, miR-130a-3p miR-146a-5p, miR-16-5p, miR-193b-3p miR-199a-3p, miR-210-3p, miR-222-3p, miR-22-3p, miR-27a-3p, miR-27b-3p, miR-335-5p, miR-454-3p, and miR-98-5p) were analyzed by quantitative real-time polymerase chain reaction in the cartilage tissues and serum samples of 28 OA patients and were compared to those of 2 healthy controls. RESULTS: Expression of microRNA-146a-5p was significantly upregulated in the cartilage (p=0.006) and serum (p=0.002) of OA patients. The expression levels of miR-146a-5p in the serum were positively correlated with those in the cartilage (Pearson correlation coefficient R=0.32; p=0.002). CONCLUSION: miR-146a-5p was significantly overexpressed in patients with OA, both in the articular cartilage tissue and serum, with a positive correlation between the levels in both types of samples. Therefore, the miR-146a-5p serum level could reflect the molecular processes in the cartilage, suggesting its clinical utility as a biomarker for OA management. Implementing noninvasive biomarker using serum miRNAs involves the analysis of the misregulated miRNAs linked to the cartilage pathology.

MiRNA expression in the cartilage of patients with osteoarthritis.

BACKGROUND: Osteoarthritis (OA), the most prevalent disease of articulating joints, is a complex multifactorial disease caused by genetic, mechanical, and environmental factors. In this research, we evaluated miRNA expression in OA. METHODS: Forty tissue samples from 29 patients undergoing joint replacement for OA were evaluated. Tissue from two control patients undergoing hip replacement not related to OA was used as a control. Total RNA (containing miRNA species) from cartilage was isolated using a miRCURYTM [corrected] Isolation Kit. Expression of 19 miRNAs was assessed by real-time quantitative polymerase chain reaction. RESULTS: Expression of four miRNAs, miR-138-5p, miR-146a-5p, miR-335-5p, and miR-9-5p, was significantly upregulated in OA tissues (patients vs. control group). CONCLUSIONS: These findings may contribute to disease prevention and the development of therapeutic targets for OA.