Intranasal therapy with miRNA-219 reduces viral load and encephalomyelitis in the TMEV model of multiple sclerosis

Purpose: RNA sequencing of spinal cord following intranasal administration of miRNA-219 in Theiler's murine encephalomyelitis virus (TMEV) model of multiple sclerosis Methods: RNA isolated from spinal cords was analyzed by Next-Generation RNA Sequencing (Illumina) Results: Here, we analyzed the therapeutic effects of miR-219 in a virus-induced demyelinating model. Following intranasal administration of miR-219 in TMEV-infected mice, we found significant reduction of clinical signs, virus persistence (virus genome copy numbers), neuroglia activation, proinflammatory cytokine levels, and demyelination. RNA sequencing of expressed host genes demonstrated that miR-219 potentiates transcriptional changes in cholesterol-related genes, leading to reduced levels of this lipid. Conclusions: Since virus replication relies on hijacking cholesterol biosynthesis and trafficking of host cell endogenous pools as well as remodeling intracellular membranes, i.e., the virus replication organelles or viroplasm, treatment with miR-219 may interfere with virus RNA replication through downregulation of cholesterol synthesis. Our findings show that miR-219 administration lessens pathological changes by reducing the CNS virus loads and favoring myelin repair. Overall design: RNA isolated from spinal cords of TMEV-infecetd mice. Experimental groups consist of healthy mice (control) and mice with chronic demyelination treated with vehicle (TMEV+veh), scrambled miR (TMEV+miR-scr) or miR-219 (TMEV+miR-219)