The role of pericytes in the pathophysiology of multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease of central nervous system (CNS) characterized with demyelination and unpredictible clinical attacks. Studies indicate that inflammation firstly starts in the peripheral immune system and then effects CNS due to the disturbance of blood brain barrier (BBB) system. Pericyte is a cell type that is mostly found in BBB and known as regulator of blood volume in veins, by virtue of its ability of contraction. Recent studies show that pericytes also have immunological functions in CNS. Our aim was to find out the interactions between MS pathogenesis and the response of pericytes to inflammation during MS pathogenesis. For this reason we immunized mice with myelin oligodendrocyte glycoprotein (MOG) to induce experimental autoimmune encephalomyelitis (EAE). We investigated EAE and pericyte interactions at early stage (15 days) and late stage (40 days) experiment groups. We observed clinical symptoms, collected sera and brain samples. We investigated the histopathology of the brain samples, serum levels of anti-MOG antibody and cytokines (IL-6, IFNγ, IL-17). Moreover human vascular pericyte cells were treated with serum samples of EAE and thereafter IL-6 and IL-17 release and viability of the cells were investigated. As a result, we showed that some pericytes gain inflammatory features and the others undergo apoptosis. Also immunohistochemistry studies showed increased pericyte content in EAE lesion sites. In conclusion we suggest that pericytes have important roles in MS pathogenesis. In future studies inflammation and apoptosis aspects of pericytes should be studied in greater detail.