Oxidized phosphatidylcholines deposition drives chronic neurodegeneration in a mouse model of progressive multiple sclerosis via IL-1β signaling.

Abstract

Oxidized phosphatidylcholines (OxPCs) are neurotoxic byproducts of oxidative stress elevated in the central nervous system (CNS) during progressive multiple sclerosis (P-MS). How OxPCs contribute to the pathophysiology of P-MS is unclear. Here we show that stereotactic OxPC deposition in the CNS of mice induces a chronic compartmentalized lesion with pathological features similar to chronic active lesions found in P-MS. Using this model, we found that although microglia protected the CNS from chronic neurodegeneration, they were also replaced by monocyte-derived macrophages in chronic OxPC lesions. Aging, a risk factor for P-MS, altered microglial composition and exacerbated neurodegeneration in chronic OxPC lesions. Amelioration of disease pathology in Casp1/Casp4-deficient mice and by blockade of IL-1R1 indicate that IL-1β signaling contributes to chronic OxPC accumulation and neurodegeneration. These results highlight OxPCs and IL-1β as potential drivers of chronic neurodegeneration in MS and suggest that their neutralization could be effective for treating P-MS.