Diindolylmethane induces miRNA-132 to potentiate cholinergic anti-inflammation and suppress autoimmune encephalomyelitis Hanieh Hamza

Abstract

The microRNAs (miRNAs) are a group of non-coding RNAs that regulate gene expression at the post-transcriptional level. An increasing paradigm has shown that these molecules are critically implicated in pathogenesis of multiple sclerosis (MS). However, the axis of miRNAs with the proteins that show important roles in MS is largely anonymous. Previously, our data showed that activation of the transcription factor aryl hydrocarbon receptor (Ahr) by 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) alleviates experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. This effect was attributed to up-regulation of miR-132 that targets acetylcholinesterase (AChE). The 3, 3'-diindolylmethane (DIM)-activated Ahr also alleviates inflammatory symptoms of EAE, but no studies have linked DIM with miR-132. Data of the current study showed that miR-132 was down-regulated in encephalitogenic CD4+ cells, while DIM restored the miR-132 level. The DIM treatment up-regulated AChE-targeting miR-132, which in turns potentiated cholinergic anti-inflammation in EAE mice. Transfection of CD4+ cells with miR-132 mimics decreased cell proliferation, interleukin (IL)-17, interferon (IFN)-γ and enhanced production of the transforming growth factor (TGF)-β. In conclusion, the findings identify a new miRNA-based mechanistic explanation for the anti-inflammatory properties of DIM in EAE, suggesting a promising therapeutic potential of miR-132 to control autoimmune inflammation in MS patients.