Circulating microRNA profiles in early-stage osteoarthritis and rheumatoid arthritis

Osteoarthritis (OA) and rheumatoid arthritis (RA) are prevalent forms of arthritis. Early detection of OA and RA is challenging with existing methods, which can delay effective management. MicroRNAs are small molecules that have emerged as promising disease biomarkers with the potential to improve early detection and differentiation of arthritis subtypes. In this study we aimed to identify distinct circulating microRNAs in plasma from individuals with early OA and early RA, using an unbiased microRNA-sequencing approach. For microRNA-sequencing, plasma samples were collected from three study groups including: (a) early OA (N=12), individuals with knee OA symptoms and radiographic Kellgren-Lawrence grade 0 or 1; (b) early RA (N=6), treatment-naïve individuals with <6 months of RA symptoms in any joint; and (c) non-OA/RA (N=44), individuals with no history of arthritis. RNA isolated from N=62 plasma samples was sequenced using a 75-base single-end read protocol at a depth of approximately 17 ± 2.5 million reads/sample on an Illumina NextSeq2000 sequencer, followed by analysis for known and novel microRNAs using a previously optimized pipeline. Overall design: Highthroughput sequencing to profile plasma microRNAs in individuals with early osteoarthritis (OA), and early rheumatoid arthritis (RA), as well as non-OA/RA controls.