Interferon-gamma production in Lyme arthritis synovial tissue promotes differentiation of fibroblast-like synoviocytes into immune effector cells.
Ontology highlight
ABSTRACT: Lyme arthritis (LA), a late disease manifestation of Borrelia burgdorferi infection, usually resolves with antibiotic therapy. However, some patients develop proliferative synovitis lasting months to several years after spirochetal killing, called postinfectious LA. In this study, we phenotyped haematopoietic and stromal cell populations in the synovial lesion ex vivo and used these findings to generate an in vitro model of LA using patient-derived fibroblast-like synoviocytes (FLS). Ex vivo analysis of synovial tissue revealed high abundance of IFN?-producing T cells and NK cells. Similar to marked IFN? responses in tissue, postinfectious LA synovial fluid also had high levels of IFN?. HLA-DR-positive FLS were present throughout the synovial lesion, particularly in areas of inflammation. FLS stimulated in vitro with B. burgdorferi, which were similar to conditions during infection, expressed 68 genes associated primarily with innate immune activation and neutrophil recruitment. In contrast, FLS stimulated with IFN?, which were similar to conditions in the postinfectious phase, expressed >2,000 genes associated with pathogen sensing, inflammation, and MHC Class II antigen presentation, similar to the expression profile in postinfectious synovial tissue. Furthermore, costimulation of FLS with B. burgdorferi and IFN? induced greater expression of IL-6 and other innate immune response proteins and genes than with IFN? stimulation alone. These results suggest that B. burgdorferi infection, in combination with IFN?, initiates the differentiation of FLS into a highly inflammatory phenotype. We hypothesise that overexpression of IFN? by lymphocytes within synovia perpetuates these responses in the postinfectious period, causing proliferative synovitis and stalling appropriate repair of damaged tissue.
SUBMITTER: Lochhead RB
PROVIDER: S-EPMC6336510 | biostudies-literature | 2019 Feb
REPOSITORIES: biostudies-literature
ACCESS DATA