title: Identification of synovial fluid microRNA signature in knee osteoarthritis: differentiating early- and late-stage knee osteoarthritis.
abstract: This study aimed to identify circulating microRNA (miRNA) signatures in knee synovial fluid (SF) from early-stage and late-stage knee osteoarthritis (OA) patients.
  
  
  
  miRNAs were screened by miRNA-PCR-arrays and validated by Real-time quantitative polymerase chain reaction (RT-qPCR) in SF from early-stage (Kellgren-Lawrence (KL): Grade: I/II) and late-stage OA patients (Grade: III/IV). OA cartilage or synovial explants were cultured to study the source/release of identified miRNAs. Computational-approach was utilized to predict gene/pathway targets.
  
  
  
  Our screening/validation analysis identified a panel of seven (out of 752) circulating miRNAs (23a-3p, 24-3p, 27a-3p, 27b-3p, 29c-3p, 34a-5p and 186-5p) that were significantly differentially expressed in late-stage vs early-stage OA-SF, irrespective of age, gender and Body Mass Index (BMI). miR-378a-5p was mostly detectable in majority of late-stage OA-SF. Cartilage explants stimulated with IL-1β showed a significant reduction in miR-23a-3p, 27a-3p and 27b-3p expression with no significant changes in other validated miRNAs. However, IL-1β-stimulated OA synovial explants exhibited significantly increased expression of miR-23a-3p, 24-3p, 27a-3p, 27b-3p, 29c-3p, 186-5p and 378a-5p, and release of only 23a-3p and 27b-3p in supernatants, suggesting that IL-1β contributes to the release of 23a-3p and 27b-3p into the SF from synovium. Computational-analysis identified 2 genes (ROQUIN-1 [RC3H1] and quaking-gene [QKI]) that are targeted by six out of eight miRNAs; miR-27b-3p exhibited greatest association with RC3H1 and QKI genes. Indeed, synovial explants treated with miR-27b-3p-mimic show significant suppression of both RC3H1 and QKI genes.
  
  
  
  We provide first evidence of the differential expression of circulating miRNAs in early-stage vs late-stage knee OA-SF. Further, we provide source, release and genes/pathways regulated by identified miRNAs.
authors.affiliation: The Arthritis Program and Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.
authors.forename: Y-H
authors.initials: YH
authors.lastname: Li
authors.affiliation: The Arthritis Program and Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.
authors.forename: G
authors.initials: G
authors.lastname: Tavallaee
authors.affiliation: Princess Margaret Cancer Centre and Department of Computer Science, University of Toronto, Ontario, Canada.
authors.forename: T
authors.initials: T
authors.lastname: Tokar
authors.affiliation: The Arthritis Program and Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Nakamura
authors.affiliation: Division of Orthopedics, Toronto Western Hospital, Toronto, Ontario, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Sundararajan
authors.affiliation: Division of Orthopedics, Toronto Western Hospital, Toronto, Ontario, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Weston
authors.affiliation: The Arthritis Program and Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Division of Orthopedics, Toronto Western Hospital, Toronto, Ontario, Canada.
authors.forename: N N
authors.initials: NN
authors.lastname: Mahomed
authors.affiliation: Division of Orthopedics, Toronto Western Hospital, Toronto, Ontario, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Gandhi
authors.affiliation: Princess Margaret Cancer Centre and Department of Computer Science, University of Toronto, Ontario, Canada.
authors.forename: I
authors.initials: I
authors.lastname: Jurisica
authors.affiliation: The Arthritis Program and Division of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada. Electronic address: mkapoor@uhnresearch.ca.
authors.forename: M
authors.initials: M
authors.lastname: Kapoor
mesh_terms: D006801:Humans; D035683:MicroRNAs; D020370:Osteoarthritis, Knee; D060888:Real-Time Polymerase Chain Reaction; D013582:Synovial Fluid; D013583:Synovial Membrane
chemical_list: D035683:MicroRNAs
keywords: Articular cartilage; Biomarker; Osteoarthritis; Synovial fluid; Synovium; miRNA