Sex-specific control of CNS autoimmunity by p38 MAPK signaling in myeloid cells

Objective: Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS), characterized by a global increasing incidence driven by relapsing-remitting disease in females. p38 MAP kinase (MAPK) has been described as a key regulator of inflammatory responses in autoimmunity, but its role in the sexual dimorphism in MS or MS models remains unexplored. Methods: Toward this end, we used experimental autoimmune encephalomyelitis (EAE), the principal animal model of MS, combined with pharmacologic and genetic inhibition of p38 MAPK activity and transcriptomic analyses. Results: Pharmacologic inhibition of p38 MAPK selectively ameliorated EAE in female mice. Conditional deletion studies demonstrated that p38 signaling in macrophages/myeloid cells, but not T cells or dendritic cells, recapitulated this sexual dimorphism. Analysis of CNS inflammatory infiltrates showed that female, but not male mice lacking p38 in myeloid cells exhibited reduced immune cell activation compared with controls, while peripheral T cell priming was unaffected in both sexes. Transcriptomic analyses of myeloid cells revealed differences in p38-controlled transcripts comprising female- and male-specific gene modules, with greater p38 dependence of pro-inflammatory gene expression in females. Interpretation: Our findings demonstrate a key role for p38 in myeloid cells in CNS autoimmunity and uncover important molecular mechanisms underlying sex differences in disease pathogenesis. Taken together, our results suggest that the p38 MAPK signaling pathway represents a novel target for much needed disease modifying therapies for MS

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Krementsov DN, Noubade R, Dragon JA, Otsu K, Rincon M, Teuscher C