P2.07: ASXL1 May Promote the Differentiation and Function of TH17 Cells

Abstract

Introduction: Kidney transplantation is the most effective method for the treatment of end-stage renal disease. However, immune rejection always restricts the survival rate of the graft. Th17 cells play an important role in renal transplantation rejection while the mechanism regulating Th17 cell differentiation and function is not fully understood. Asxl1 is an epigenetic regulatory factor frequently mutated in myeloid malignancies, but the role of Asxl1 in immune rejection or T cell development and differentiation has not been reported. Method: Lymph nodes were isolated from wild-type mice (CD4Cre-Asxl1F/F, WT) and CD4+ T cell conditional Asxl1 knockout mice (CD4Cre+Asxl1F/F, KO), and CD4+CD25-CD44-CD62L+ naive T lymphocytes were sorted by the method of flow cytometry. The sorted cells mentioned above were stimulated with IL-1β (10 ng/mL), IL-23 (50 ng/mL), IL-6 (50 ng/mL), TGF-β (5 ng/mL), anti-IL-4 (10 μg/mL) and anti-IFN-γ (10 μg/mL) according to the cell density of 1×105/well for 72 h, and then Monensin (2 μmol/L), Brefeldin A (5 μg/mL), Ionomycin (0.5 μg/mL) and PDBU (1 μmol/L) were added for further stimulation for 4 h at 37℃ and 5% CO2. The stimulated cells were collected and the number and proportion of CD4+IL-17+ cells were analyzed by flow cytometry. The differentiation of Th1, Th2 and Treg cells were induced from WT mice by similar methods in vitro, and the expression of Asxl1 in different cell subsets were detected by Real-Time PCR at mRNA level. Results: Compared with the WT mice, the number and proportion of Th17 cells in KO mice were significantly decreased. The mRNA expression level of Asxl1 in Th17 cell subsets from WT mice was the highest. Conclusion: The results suggest that Asxl1 may promote the differentiation and function of Th17 cells as a positive factor. Asxl1 may become a new immune rejection target to regulate the number or function of Th17 cells, which has potential clinical significance in the intervention and prevention of rejection after kidney transplantation.