miRNA expression in Th17 cells after AhR activation

Th17 cells play a major role in the pathogenesis of Rheumatoid Arthritis, and it is well known the involvement of the Aryl Hydrocarbon Receptor (AhR) during the differentiation and activation of these cells. Due to its function as a transcription factor, we tested wether AhR would mediate part of its function in Th17 cells through the transcription of microRNAs (miRNAs). Therefore, we first perform a microarray experiment to identify the miRNAs induced after AhR activation in Th17 cells. Under a supervised hierarchical clustering, we identify 224 miRNAs differentially expressed (fold-change ³ 2.0 and FDR < 5%). Among them, 22 miRNAs were up regulated exclusively in Th17 cells in the presence of FICZ. Naïve T cells were differentiated in the presence of IL-6, TGF-b and IL-1. After 3 days, IL-17 producer cells were isolated and re-stimulated with IL-6, TGF-b, IL-1, and IL-23 in the presence or absence of FICZ for 24h. Th0 conditions used as a control, and isolated CD4+ T cells were re-stimulated with IL-2, in the presence or absence of FICZ during the same time.