Multiple sclerosis (MS) targets the myelin sheath of central nervous system (CNS) neurons. MS is initiated by autoreactive CD4+ T cells, and obesity is known be associated with an increased risk of MS, particularly in women. A study in Cell Metabolism now identifies a female-specific mechanism by which obesity increases the risk of MS by promoting a pro-inflammatory T helper 1 (TH1) CD4+ T cell phenotype.

To investigate these sex-dependent inflammatory signatures further, the researchers used a diet-induced-obesity (DIO) mouse model combined with experimental autoimmune encephalomyelitis (EAE), a mouse model of MS in which T cells are autoreactive against myelin. EAE progression and symptoms were exacerbated to a greater extent by DIO (compared with normal-weight EAE controls) in female compared with male mice.