Effect of Halofuginone on the Pathogenesis of Autoimmune Thyroid Disease in Different Mice Models

Our objectives were to investigate the therapeutic effect of halofuginone (HF) in the treatment of autoimmune thyroid diseases (AITDs) and explore its underlying mechanism of action.The Graves' disease (GD) model was generated by immunizing female BALB/c mice with adenovirus expressing the TSH receptor A subunit (Ad-TSHR289). The Ad-TSHRA+HF and Ad- TSHRA+DMSO groups were injected intraperitoneally with HF or the vehicle control (DMSO), respectively. The autoimmune thyroiditis (AIT) group consisted of female NOD.H-2h4 mice that were administered NaI in the drinking water and intraperitoneally injected daily with the vehicle control (DMSO) during the study period. The AIT/HF group consisted of female NOD.H-2h4 mice that were administered NaI in the drinking water and intraperitoneally injected daily with HF. The frequencies of splenic Th17 cells, Tregs and Bregs were determined by flow cytometry. The mRNA levels of IL-17, forkhead box P3 (Foxp3), RORγt and IL-10 were determined by real-time PCR.In both Ad-TSHRA+DMSO and Ad-TSHRA+HF groups, 10 out of 15 mice displayed serum T4 and TSAb levels above 3 SD beyond the mean control levels. The number of CD4+CD25+Foxp3+ T lymphocytes in the GD model was significantly increased in the HF group compared with the DMSO group (P < 0.05). The mRNA level of Foxp3 was significantly increased in the Ad-TSHRA+HF group compared with the Ad-TSHRA+DMSO group (P < 0.05). However, neither the abundance of CD4+IL-17+ T cell subpopulation nor the mRNA expression level of RORγt differed significantly between the Ad-TSHRA+HF and Ad-TSHRA+DMSO groups (P > 0.05). The serum TgAb titer was significantly reduced in the AIT/HF group compared with the AIT group (P < 0.01). The differences in the number of CD4+CD25+Foxp3+ T lymphocytes and the mRNA levels of Foxp3 between the AIT/HF and AITgroups were not significant (P > 0.05). However, the number of CD4+IL-17+ T cells and the mRNA levels of IL-17 and RORγt were significantly increased in HF-treated mice compared with the non-treated AIT-induced mice (P < 0.05).Treatment with HF significantly decreased the incidence of AIT by decreasing the number of CD4+IL-17+ T cells.