Identification of Small Molecule Inhibitors of a Mir155 Transcriptional Reporter in Th17 Cells

MicroRNA miR-155 is an important regulatory molecule in the immune system and is highly expressed and functional in Th17 cells, a subset of CD4(+) T helper cells which are key players in autoimmune diseases. Small molecules that can modulate miR-155 may potentially provide new therapeutic avenues to inhibit Th17 cell-mediated autoimmune diseases. Here, we present a novel high-throughput screening assay using primary T cells from genetically engineered Mir155 reporter mice, and its use to screen libraries of small molecules to identify novel modulators of Th17 cell function. We have discovered a chemical series of (E)-1-(phenylsulfonyl)-2-styryl-1H-benzo[d] imidazoles as novel down-regulators of Mir155 reporter and cytokine expression in Th17 cells. In addition, we found that FDA approved antiparasitic agents belonging to the ‘azole’ family also down-regulate Mir155 reporter and cytokine expression in Th17 cells, and thus could potentially be repurposed to treat Th17-driven immunopathologies.