Endocrine Abstracts

Context: Aberrant CD4+T cell function plays a critical role in the process of Graves’ disease (GD). MicroRNAs (miRNAs) are important regulators of T cell activation, proliferation and cytokine production. However, the contribution of miRNAs to CD4+T cell dysfunction in GD remains unclear.

Objective: To investigate how certain miRNA causes aberrant CD4+T cell function in GD patients.

Methods: We compared the expression pattern of miRNAs in CD4+T cells from untreated GD patients with those from healthy controls. The most significantly dysregulated miRNAs were selected and their correlations with clinical parameters were analyzed. The effect of miR-4443 on CD4+T cells cytokines production and proliferation was assessed. The potential gene target was identified and validated.

Results: GD patients had unique pattern of miRNA expression profile in CD4+T cells comparing to healthy subjects. MiR-10a, miR-125b and miR-4443 were the three most significantly dysregulated miRNAs. The elevated miR-4443 levels were strongly correlated with clinical parameters in an independent dataset of untreated GD patients (N=40) while miR-4443 was normally expressed in GD patients with euthyroidism and negative TRAb level. We found that miR-4443 directly inhibited TNFR-associated factor (TRAF) 4 expression to increase CD4+T cells cytokines secretion as well as proliferation through the NF-κB pathway. Furthermore, the TRAF4 levels in GD patients were inversely correlated with miR-4443, and knocking down TRAF4 had a similar effect with miR-4443 overexpression.

Conclusion: The increased expression of miR-4443 induced CD4+T cells dysfunction by targeting TRAF4, which may cause Graves’ diseases.