Abstract 31: Umbilical Cord Blood Derived Macrophages, DUOC-01, Suppress Neuroinflammation by Protecting the Blood Brain Barrier

Abstract Introduction The central nervous system (CNS) has a specialized barrier, the blood brain barrier (BBB), that tightly regulates the entry of circulating blood cells and molecules. The BBB is compromised in many neurodegenerative diseases, thus understanding BBB dysfunction is critical to treating neurodegenerative diseases, like multiple sclerosis (MS). CNS macrophages regulate the BBB and have potential for development as a cell therapy. Objectives In this study, we tested if umbilical cord blood derived macrophages (DUOC-01) could prevent BBB dysfunction and suppress the progression of disease in as mouse model of MS. Methods We utilized the experimental autoimmune encephalomyelitis (EAE) mouse model for MS. To initiate EAE, we immunized C57BL/6 mice with myelin oligodendrocyte glycoprotein peptide (MOG35-55) in complete Freund’s adjuvant. We manufactured DUOC-01 from cord blood as previously described and injected into the cerebrospinal fluid at the onset of EAE symptoms. We measured clinical paralysis, immune cell infiltration, and BBB integrity. Results DUOC-01 suppressed clinical scores over 21 days of EAE accompanied by decreased infiltration of leukocytes induced by the disease. Mice treated with DUOC-01 had less infiltrating neutrophils, and Ly6Chi and Ly6Clo macrophages in the lumbar spinal cord. Myeloid cell attracting chemokines: CCL2, CXCL1, and CCL4 were decreased in DUOC-01 treated group. Using immunohistochemistry, we determined tight junction proteins, ZO-1 and Claudin-5, on endothelial cells of BBB decreased in EAE and this was blocked by DUOC-01. To study the direct effects of DUOC-01 on brain endothelial cells, we set up primary mouse brain endothelial cell culture. In co-cultures, DUOC-01 suppressed secretion of CCL2, CXCL1, and CCL4 from activated endothelial cells. Using a transwell migration assay, we found DUOC-01 suppressed myeloid cell migration through activated endothelial cells. Discussion In this study, we determined DUOC-01 alleviated EAE, at least in part by suppressing the activation of brain endothelial cells. This restored BBB function, suppressed chemokine expression and immune cell infiltration. Overall, our data suggest that DUOC-01 could be beneficial in reducing neuroinflammation in neurodegenerative diseases, like MS.