The role of cytokines and T-bet, GATA3, ROR-γt, and FOXP3 transcription factors of T cell subsets in the natural clinical progression of Type 1 Diabetes

Abstract

Th cells play an important role in pathogenesis of type 1 diabetes (T1D). Peripheral blood mononuclear cells were isolated from peripheral blood samples from newly diagnosed (ND), 1-year (1YD), and 5-year T1D (5YD) patients (n:8 of each group), 8 healthy controls (HC), and cultured for 24 h under unstimulated (US) and stimulated conditions. Cell ratios of Th1, Th2, Th17, Treg, and intracellular levels of IFN-γ, TNF-α, IL-10, TGF-β, IL-5, IL-13, IL-17, and IL-21 cytokines were evaluated using the flow cytometry. mRNA expressions of transcription factors T-bet, GATA3, ROR-γt, and FOXP3 of these cells were determined by real-time PCR. Reduced CD4⁺CD25^high cell ratios were detected in ND. CD4⁺CD25^high cells were found to be reduced in ND and 1YD compared to HC under IL-2-stimulated conditions. Intracellular IFN-γ and TNF-α levels were low in all patients under US and IL-12-stimulated conditions. IL-17A and IL-21 were found to be high in patients with IL-6-stimulated conditions. Expressions of IL-10 and TGF-β have been observed to be reduced in patients. Th1/Th2, Th17/Treg, and Th1/Treg ratios were higher in patient groups. FOXP3 and GATA3 mRNA expressions were found to be low in patients, while RORγt and T-bet mRNA levels were higher than HC. Th1, Th17, and Treg cells and their cytokines have been shown to be associated with type 1 diabetes.

Keywords: FOXP3; GATA3; IFN-γ; IL-10; IL-13; IL-17; IL-21; IL-5; ROR-γt; T-bet; TGF-β; TNF-α; Th1; Th17; Th2; Treg; Type 1 diabetes.