Positive and Negative Regulation of Th17 Cell Differentiation: Evaluating the Impact of RORC2

Objective: th17 cells are known to be involved in some types of inflammations andautoimmune disorders. rorc2 is the key transcription factor coordinating th17 celldifferentiation. thus, blocking rorc2 may be useful in suppressing th17-dependentinflammatory processes. the aim was to silence rorc2 by specific sirnas in naïvet cells differentiating to th17. time-dependent expression of rorc2 as well as il-17and il-23r were considered before and after rorc2 silencing.materials and methods: in this experimental study, naïve cd4+ t cells were isolated fromhuman cord blood samples. cytokines tgfb plus il-6 and il-23 were used to polarize the naïvet cells to th17 cells in x-vivo 15 serum free medium. a mixture of three sirnas specificfor rorc2 was applied for blocking its expression. rorc2, il-17 and il-23r mrna and proteinlevels were measured using qrt-pcr, elisa and flow cytometry techniques. pearsoncorrelation and one-way anova were used for statistical analyses.results: significant correlations were obtained in time-dependent analysis of il-17 andil-23r expression in relation with rorc2 (r=0.87 and 0.89 respectively, p < 0.05). silencingof rorc2 was accompanied with almost complete suppression of il-17 (99.3%;p < 0.05) and significant decrease in il-23r gene expression (77.2%, p < 0.05).conclusion: our results showed that rorc2 is the main and the primary trigger for upregulationof il-17 and il-23r genes in human th17 cell differentiation. moreover, weshow that day 3 could be considered as the key day in the th17 differentiation process.