Interleukin-34 overexpression mediated through tumor necrosis factor-alpha reflects severity of synovitis in knee osteoarthritis.

ABSTRACT: This study aimed to investigate whether interleukin-34 (IL-34) mRNA expression is aberrant and modulated by tumor necrosis factor-alpha (TNF-?) in knee osteoarthritis (OA) fibroblast-like synoviocytes (FLS) and determine associations of IL-34 mRNA and protein in the systemic and local joint environments with severity of knee OA synovitis. Transcriptional and translational IL-34 levels in FLS, synovium, synovial fluid, and plasma of knee OA were determined using real-time polymerase chain reaction, immunohistochemistry, and enzyme-linked immunosorbent assay. Relative mRNA expressions of NF-?B signaling molecules were further measured. In knee OA FLS stimulated with TNF-?, IL-34 mRNA expression was significantly up-regulated in a time-dependent manner. In knee OA synovium with severe synovitis, increased IL-34 mRNA expression was directly associated with IL-6, I?B, NF-?B, and MMP-13, in addition to knee OA FLS. Immunostaining score of IL-34 was considerably greater in knee OA synovium with severe synovitis than that in those with mild and no synovitis. Increments in joint fluid and plasma IL-34 levels in knee OA patients with severe synovitis were closely related to its mRNA and protein expressions in knee OA synovium. Transcriptional and translational expressions of IL-34 were positively correlated with synovitis severity. Collectively, IL-34 overexpression would reflect synovitis severity in knee OA.

SUBMITTER: Udomsinprasert W 

PROVIDER: S-EPMC7224362 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature