Modulation Of Leptin/pCons To T Cells And Their Impacts On Lupus

Part Ⅰ Effect of Leptin on Th17and its Impact on LupusObjective Systemic lupus erythematosus(SLE), a systemic autoimmune disease characterized by regulatory T cells (Treg) failing to suppress effector T cells (Teff). Thl7, a main kind of effector T cells, promotes inflammation and autoimmune responses in several animal models of autoimmune diseases.Leptin,a cytokine like hormone,can link nutritional status and immune responses by directly modulating the production of inflammatory mediators and the activation, proliferation and maturation of different immune cell subsets. Importantly, leptin accelerates the development and progression of several kinds of autoimmune diseases. But the role of leptin in the differentiation and activity of Th17cells in SLE has not been explored.The present study aims at investigating the effect of leptin to Th17and its impact on lupus.Methods Th17cells were compared in peripheral blood,spleen, and IL-17levels in plasma, among wild-type (WT) C57B1/6J (B6), ob/ob leptin-deficient and db/db leptin receptor-deficient mice (also on the B6background). The possibility of direct Thl7cell modulation in the peripheral blood was investigated by administering saline/leptin/anti-leptin to ob/ob mice or (NZB×NZW)F1(NZB/W) lupus mice in vivo, and the effects of scalar doses of leptin were evaluated on Th17from ob/ob mice or NZB/W lupus mice in vitro,and on the expression of the Th17master regulator RORyt (detected as luciferase activity after retroviral transfection of cells with a reporter construct encoding RORyt).The effects of scalar dose of leptin on Th17from healthy human and the relationship between leptin and IL-17from plasma of SLE patients or healthy control was evaluated.Results Fewer Th17cells and reduced levels of plasma IL-17were found in ob/ob mice and db/db mice as compared with WT mice. Leptin administration in ob/ob mice promoted Th17cell response both in vivo and in vitro. RORyt expression and differentiation of Th17cell was facilitated by leptin. In NZB/W lupus mice, leptin enhanced Th17cell expansion, both in vivo and in vitro.A positive correlation between plasma leptin and IL-17in the SLE patients but not in the controls was found.Conclusion Leptin works as a positive regulator to Th17and promotes Th17differentiation by enhancing RORyt expression. These results suggest that leptin could be targeted for IL-17modulation in states characterized by autoimmune responses such as in SLE. Part Ⅱ Effect of pCons on Teff and its Impact on LupusObjective Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease characterized by the presence of dysregulated mechanisms of immune tolerance that include reduced numbers and/or function of Treg,over-activated effect of Teff, and resistance of Teff to Treg suppression. We had previously shown that the treatment of NZB/W lupus-prone mice with the anti-DNA Ig peptide pCons effectively delayed lupus-like disease and prolonged mice survival.We also showed that part of the protection had to be ascribed to pCons induced Treg that suppressed autoimmune responses in a p38-dependent fashion. However,the effects of pCons on Teff remained elusive.The present study aims at evaluating effect of pCons on Teff and its impact on lupus.Methods Molecular pathways related to cell cycle, anergy and T cell receptor signaling in sorted Teff from pCons-treated NZB/W mice versus controls were analyzed by western-blot; CFSE-labeled Teff from pCons-tolerized or control (pNeg-treated) NZB/W mice were cultured with Treg from pCons-tolerized or control NZB/W mice in the presence of CD3/CD28for3days; NZB/W mice were injected with p38inhibitor SB203580or with control SB202474or saline for14days. On day7,mice were tolerized with pCons or left untreated, and on day15Teff and Treg were isolated for functional studies.Results No differences were observed in the activation of ZAP-70, p27, ERK, STAT1, STAT3, STAT6, JNK, SAPK and p38in Teff from pCons tolerized mice and controls. pCons facilitates Teff suppression by Treg,which are p38independent.Conclusion pCons induced immune tolerance in NZB/W lupus mice facilitated Teff suppression by Treg.These new findings indicate that pCons exerts protective effects in NZB/W lupus mice by differentially modulating the activity of different T cell subsets, implying new considerations in the design of Treg-based approaches to modulate T cell autoreactivity in SLE.