Effects of leptin on Th17 cells and the possible mechanism / 中华微生物学和免疫学杂志

ABSTRACT

Objective To investigate the effects of leptin on Th17 cells and the possible mechanism. Methods The leptin-deficient ( ob/ob) mice and their homologous wild-type mice were used in the study.The percentages of Th17 cells in peripheral blood samples, spleen tissues and lymph nodes were measured by flow cytometry ( FCM) analysis.The splenic CD4+T cells, separated from the ob/ob mice and the wild-type mice by using magnetic beads,were respectively cultured with leptin at various concentrations and with anti-leptin neu-tralization antibody to evaluate the effects of leptin on Th17 cells.The quantitative real-time PCR was performed to analyze Th17 cell-related cytokines at transcriptional levels.The levels of IL-6 and IL-17A in the supernatants of CD4+T cell culture were measured with Luminex technology.Results Compared with the wild-type mice, the ob/ob mice showed lower percentages of Th17 cells in both peripheral blood samples and spleen tissues (0.49%±0.03%vs 1.29%±0.1%, 1.56%±0.22%vs 2.47%±0.11%).There was a decrease in the percentages of Th17 cells upon the in vitro treatment of CD4+T cells from wild-type mice with anti-leptin antibody.The per-centages of Th17 cells were increased in a dose-dependent manner upon the in vitro treatment of CD4+T cells from ob/ob mice with leptin.Moreover, the levels of IL-17A and IL-6 and the transcriptional levels of RORγt, IL-17A and IL-6 in leptin deficiency group were lower than those of wild-type group, but were increased upon the treatment with leptin.No significant difference with the transcriptional levels of TGF-βand IL-23 was ob-served between the two groups with and without intervention.Conclusion Leptin deficiency seriously hampered the generation of Th17 cells in mice and resulted in a decreased expression of RORγt, IL-17A and IL-6 at mRNA level.The treatment of CD4 T cells with leptin might promote the generation of Th17 cells through up-regulating the transcription of RORγt and IL-6.