Mycoplasmas are the causal agent of arthritis in mammals, in fact lipoproteins and lipopeptides are Pathogen Associated Molecular Patterns (PAMPs) that interact with TLR causing release of pro-inflammatory cytokines and chemokines. Fibroblast-like synoviocytes (FLS) play a key role in pathogenesis of arthritis causing cytokines release that perpetuates inflammation.
This study evaluate the ability of synthetic lipopeptide LipoP48 from M. agalactiae-derived lipoprotein P48 to trigger innate immunity using an in vitro approach, by qPCR for cytokines/chemokines expression (IL1β, TNF-α, IL6, IL8, GMCSF, Mip1β), and by immunofluorescence for MHCII, TLR2, CD80 and CD86 in ovine FLS.
FLS stimulated with increasing concentrations of LipoP48 showed a dose-dependent expression of TNF-α, IL-6, IL-8 and GM-CSF. High levels of IL6, IL8 and GMCSF were found at different time point. Post stimulation, an increased expression of TLR2 and MHCII, CD80 and CD86 expression were induced. Neither stimulation with the peptide sequence nor with synthetic molecule pam2cys have been successful. Lack of MHCII expression induced by LipoP48 was observed when TLR2 have been blocked. Results show that LipoP48 acts as a potent immunomodulator, triggering the production of pro-inflammatory cytokines in ovine FLS.
These data suggest a role of mycoplasmas PAMPs in the onset of the articular inflammatory process, and propose a useful model for the study of arthritis pathogenesis of bacterial etiology in mammals.</br
