Role of sex hormones in CD4+ T-cell mediated rheumatoid arthritis pathology

BackgroundAn adverse female sex-bias exists across many autoimmune disorders, yet its underlying mechanisms, particularly the role of sex hormones, remains poorly understood. Furthermore, the physiological influence of sex hormones in regulating T cell function remains undefined. We examined for the critical role of estrogen and progesterone, in regulating CD4+ T cell responses, specifically with respect to inflammation and their bone erosion potential in RA. MethodsInflammatory markers, circulating antibodies, sex hormone receptors, ER and PR levels were investigated in both RA patients and controls. Further, RA CD4+ T cells were stimulated in varying concentrations of estradiol and progesterone and assessed for modulation in cytokines, transcription factors, RANKL, and FasL expression. Subsequent ex-vivo studies were performed to examine the role of sex hormones in modulating T cell responses. ResultsRA patients displayed systemic inflammation and high circulating antibodies, with significantly higher expression in synovial fluid. Higher expression of ER and PR was evinced on RA CD4+ T cells. Upon hormone stimulation, two cohorts of patients namely responders and non-responders were observed with respect to modulation in cytokines, transcription factors, RANKL, and FasL expression. Our ex-vivo Th1 and Th17 cells demonstrated that sex hormones play a physiological role in modulating inflammation and have bone erosion potential. ConclusionOur findings demonstrate the pivotal significance of sex hormones in modulating TCR responses, thereby regulating inflammation and bone erosion in RA pathology. Further dissection of TCR signaling pathways with respect to sex hormone stimulation may provide promising targets for therapeutic implications. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=142 SRC="FIGDIR/small/25342530v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@15a5ee5org.highwire.dtl.DTLVardef@c405forg.highwire.dtl.DTLVardef@562534org.highwire.dtl.DTLVardef@1a4835a_HPS_FORMAT_FIGEXP M_FIG C_FIG