Session Title: Biology and Pathology of Bone and Joint - Poster II
Session Type: ACR Poster Session B
Session Time: 9:00AM-11:00AM
Background/Purpose: Exosomes are small membrane vesicles (40-150 nm) of endocytic origin secreted by many types of cells and engage in cell-to-cell communication by transferring proteins, microRNAs, mRNA, and lipid to recipient cells. Exosomes are also identified in various biological fluids including blood, urine, amniotic fluid, saliva, malignant ascites, and synovial fluid. We investigated the effect of synovial exosomes on osteoclast differentiation in inflammatory arthritis.
Methods: Synovial exosomes were isolated from SF of rheumatoid arthritis (RA, n=16), ankylosing spondylitis (AS, n=7), gout (n=9), and osteoarthritis (OA, n=8) patients. The size and morphology of synovial exosomes was evaluated by transmission electron microscopy. The number of synovial exosomes was assessed by acetylcholinesterase activity and CD81-ELISA. Monocytes isolated from healthy peripheral blood mononuclear cells (PBMCs) were differentiated into macrophages by treatment of macrophage colony-stimulating factor (M-CSF). Then, macrophages were incubated with synovial exosomes without M-CSF and receptor activator of nuclear factor kappa-B ligand (RANKL). Cell proliferation was determined using cell counting kit-8 assay. Osteoclast differentiation was evaluated by tartrate resistant acid phosphatase (TRAP) stain. Cellular uptake of CFSE-labeled exosomes was analyzed by confocal microscopy.
Results: The size of synovial exosomes ranged from 20 to 150 nm. The number of exosomes in the same volume of synovial fluid was higher in SF of RA (p=0.0235), AS (p=0.0135), and gout (p=0.2245) patients compared to OA patients. Exosomes from RA (p=0.8639), AS (p=0.0823), or gout (p=0.2571) SF induced higher macrophage proliferation compared to those from OA SF but the difference was not significant. Exosomes from RA or AS SF induced osteoclastogenesis in the absence of M-CSF and RANKL. Osteoclast formation was significantly increased in the presence of RA (p=0.01) exosomes compared to OA exosomes, but not in AS or gout. Synovial exosomes labeled with CFSE were internalized by macrophage and enriched in perinuclear space.
Conclusion: The number of exosomes was increased in SF of RA and AS compared to OA. Exosomes from SF of RA induced osteoclast differentiation.
To cite this abstract in AMA style:Song JE, Shin JH, Moon KW, Shon SH, Park JS, Lee EB, Song YW, Lee EY. Synovial Exosomes Induce Osteoclast Differentiation in Rheumatoid arthritis [abstract]. Arthritis Rheumatol. 2016; 68 (suppl 10). https://acrabstracts.org/abstract/synovial-exosomes-induce-osteoclast-differentiation-in-rheumatoid-arthritis/. Accessed December 2, 2020.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/synovial-exosomes-induce-osteoclast-differentiation-in-rheumatoid-arthritis/