ABSTRACT
Objective To investigate the effect of interferon-γ(IFN-γ) on the expression of indoleamine 2,3-dioxygenase(IDO),and tryptophanyl-tRNA-synthetase (TTS) in thyrocytes; and to study the relevant immunopathological significance in Graves' disease.Methods The expressions of IDO and TTS genes in IFN-γ stimulated Nthy-ori3-1 cell line and human thyrocytes,as well as in human thyroid tissues were determined by realtime quantitative PCR.Results IDO and TTS genes were expressed slightly in both Nthy-ori3-1 cell line and human thyrocytes,and were significantly up-regulated after IFN-γ stimulation(P＜0.01).Compared to healthy controls,TTS mRNA level was higher in thyroid tissues of patients with Graves' disease (P =0.018 2),while IDO mRNA level showed no difference,but was notably correlated with IFN-γ mRNA level (R2 =0.716,P =0.002).Conclusion In the early stage of Graves' disease,thyrocytes may decompose local tryptophan by enhancing the expression of IDO and TTS under IFN-γstimulation,thus inhibit auto-reactive function of lymphocytes and balance excessive autoimmune reaction.
ABSTRACT
Objective To explore the impact of dexamethasone on inflammatory response of thyrocytes.Methods Primary thyrocytes were extracted from thyroid tissue of patients with Graves' disease.The cells were stimulated with interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α),and cultured in dexamethasone.Thyrocytes were divided into 4 groups:control group,dexamethasone group,TNF-α + IFN-γ group,and dexamethasone+TNF-α+IFN-γ group.Interferon-γ-induced protein 10 (CXCL10) and CCL2 in supernatant of cell cultured in 4 groups were detected by enzyme-linked immunosorbent assay.Cell protein in 4 groups was extracted and GSK-3β,P50,and P100 protein were detected by Western blotting.Results MTT assay demonstrated that 10-5 mmol/L concentration of dexamethasone was optimal for cell culture.The CXCL10 level in TNF-α+IFN-γ group was higher than that in the control group and dexamethasone group (P＜0.01),but no difference was found between dexamethasone+TNF-α+IFN-γgroup and TNF-α+IFN-γgroup(P＞0.05).The CCL2 level in TNF-α+IFN-γ group was higher than that in control group and dexamethasone group(P＜0.01).There was a significant lowering of CCL2 level in dexamethasone + TNF-α + IFN-γgroup compared with TNF-α + IFN-γ group (P ＜ 0.05).The expression of GSK-3β and P100 protein was increased in TNF-α + IFN-γgroup compared with control group.The expression of GSK-3β and P100 protein was lower in dexamethasone+TNF-α + IFN-γ group than that in TNF-α + IFN-γ group.Conclusion TNF-α + IFN-γ could stimulate the secretion of CXCL10 and CCL2 in thyrocytes and thus activate the inflammatory response.Dexamethasone could reduce CCL2 secretion.Dexamethasone had little effect on CXCL10.Dexamethasone could reduce GSK-3β and P100 expressions,and inhibit the activation of NF-κB signaling pathway and thus the inflammatory response.
ABSTRACT
Thyrocytes expressing MHC class Ⅱ molecules were separated from transgenic mice and were co-cultured with autologous spleen T lymphocytes. T cells did not proliferate and were not activated, but CD4+ T cells were promoted into apoptosis.