Recombinant ADAMTS13 Exerts Neuroprotective Effects On Experimental Autoimmune Encephalomyelitis Mice

Background and ObjectivesADAMTS13（Von Willebrand Factor Lysis Protease）is a metalloproteinase that plays an important role in preventing microvascular thrombosis.In recent years,recombinant ADAMTS13 has been widely used to inhibit the inflammatory response of atherosclerosis and stroke models.In addition,it has been demonstrated that inflammatory responses play a crucial role in the pathogenesis of multiple sclerosis.Recent study has reported reduced ADAMTS13 level in plasma of multiple sclerosis patients.Therefore,we established a classical animal model of multiple sclerosis（MS）,experimental autoimmune encephalomyelitis（EAE）,to investigate whether recombinant ADAMTS13 treatment ameliorates the development of EAE.MethodsThe EAE model was constructed by immunizing female 8-week-oldC57BL/6 mice with myelin oligodendrocyte glycoprotein(MOG₃₅–₅₅)peptide and then randomly divided into ADAMTS13 group and vehicle group.Recombinant ADAMTS13 or vehicle was injected into the lateral ventricle daily prophylactically 7-21 dpi and therapeutically 15-29 dpi in the course of EAE.The clinical scores,body weight,highest score and onset time of EAE mice were evaluated.Histochemical stains（HE,LFB）were used to detect pathological changes such as inflammatory cell infiltration and myelin loss in frozen sections of EAE mice spinal cords.Immunofluorescence staining（CD3,Iba1,Ly6g）and flow cytometry were used to detect the infiltration of T lymphocytes,microglia and neutrophils in spinal cord tissue.To further explore the potential mechanism of recombinant ADAMTS13,ELISA was used to evaluate the levels of IL-1β,IL-17 and IFN-γin the spinal cords.The expression of CXCL1 and CCL2 in the spinal cords of EAE mice were detected by real-time PCR.Evans blue and Western blot were adopted to assess the blood-spinal cord barriers（BSCB）of EAE mice.The effect of recombinant ADAMTS13 on cell subsets in peripheral blood and spleen was determined by flow cytometry.ResultsCompared with the vehicle group,therapeutic administration of recombinant ADAMTS13 can improve clinical symptoms,reduce infiltration of inflammatory cells and demyelination in the spinal cord tissue of EAE mice.Similarly,prophylactic administration of recombinant ADAMTS13 can significantly improve clinical symptom,reduce infiltration of inflammatory cells and loss of myelin in spinal cord tissue.Immunofluorescence and flow cytometry results suggest that prophylactic administration of ADAMTS13 reduces the numbers of infiltrated T lymphocytes and neutrophils in spinal cord tissue.Flow cytometry results showed that leukocytes in the blood and spleen of EAE mice were not affected by administration of ADAMTS13.Reduced levels of IL-1βand IL-17 cytokines in the spinal cord of EAE mice,decreased expression of CXCL1and CCL2 chemokines,and reduced blood-spinal barrier damage are involved in the inflammatory inhibition and neuroprotection of recombinant ADAMTS13 in EAE mice.ConclusionThe findings reveal that recombinant ADAMTS13 significantly inhibits CNS inflammation and thus provides obvious neuroprotection for EAE mice.Recombinant ADAMTS13 may represent a new therapy for MS.