CLMP Promotes Leukocyte Migration Across Brain Barriers in Multiple Sclerosis
Antoine Philippe Fournier1, Stephanie Zandee1, Marc Charabati1
1From the Neuroimmunology Research Laboratory (A.P.F., S.Z., M.C., E.P., O.T., J.I.A., H.K., L.B., S.L., B., W.K., F.T., P.D., C.L., N.A., M.D.,P.D.A.P.), Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM); Department of Neurosciences (A.P.F., S.Z., M.C., E.P., F.T., C.L., N.A., M.D.,P.D.A.P.), Faculty of Medicine, Université de Montréal; Department of Microbiology (H.K.), Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal; Multiple Sclerosis Clinic (B., P.D., M.G., C.L., N.A., M.D.,P.D.A.P.), Division of Neurology, Centre Hospitalier de l'Université de Montréal (CHUM); Division of Neurosurgery (A.B., R.M.), Université de Montréal & CHUM; and Department of Pathology (R.C.), Université de Montréal & CHUM, Quebec, Canada.
Background And Objectives:
In multiple sclerosis (MS), peripheral immune cells use various cell trafficking molecules to infiltrate the CNS where they cause damage.The objective of this study was to investigate the involvement of coxsackie and adenovirus receptor-like membrane protein (CLMP) in the migration of immune cells into the CNS of patients with MS.
Methods:
Expression of CLMP was measured in primary cultures of human brain endothelial cells (HBECs) and human meningeal endothelial cells (HMECs), postmortem brain samples, and peripheral blood mononuclear cells (PBMCs) from patients with MS and controls by RNA sequencing, quantitative PCR, immunohistochemistry, and flow cytometry. In vitro migration assays using HBECs and HMECs were performed to evaluate the function of CLMP.
Results:
Using bulk RNA sequencing of primary cultures of human brain and meningeal endothelial cells (ECs), we have identified CLMP as a new potential cell trafficking molecule upregulated in inflammatory conditions. We first confirmed the upregulation of CLMP at the protein level on TNFα-activated and IFNγ-activated primary cultures of human brain and meningeal ECs. In autopsy brain specimens from patients with MS, we demonstrated an overexpression of endothelial CLMP in active MS lesions when compared with normal control brain tissue. Flow cytometry of human PBMCs demonstrated an increased frequency of CLMP+ B lymphocytes and monocytes in patients with MS, when compared with that in healthy controls. The use of a blocking antibody against CLMP reduced the migration of immune cells across the human brain and meningeal ECs in vitro. Finally, we found CLMP+ immune cell infiltrates in the perivascular area of parenchymal lesions and in the meninges of patients with MS.
Discussion:
Collectively, our data demonstrate that CLMP is an adhesion molecule used by immune cells to access the CNS during neuroinflammatory disorders such as MS. CLMP could represent a target for a new treatment of neuroinflammatory conditions.
Insights
Coxsackie and adenovirus receptor-like membrane protein (CLMP) is upregulated in multiple sclerosis (MS) and facilitates immune cell entry into the central nervous system (CNS). Targeting CLMP may offer new therapeutic strategies for neuroinflammatory diseases.
Area of Science:
- Neuroimmunology
- Cellular and Molecular Neuroscience
Background:
- Peripheral immune cells infiltrate the central nervous system (CNS) in multiple sclerosis (MS), mediated by cell trafficking molecules.
- Understanding these molecular mechanisms is crucial for developing targeted therapies for MS.
Purpose of the Study:
- To investigate the role of coxsackie and adenovirus receptor-like membrane protein (CLMP) in immune cell migration into the CNS in MS patients.
Main Methods:
- Expression analysis of CLMP in human brain and meningeal endothelial cells, postmortem brain samples, and peripheral blood mononuclear cells (PBMCs) from MS patients and controls.
- In vitro migration assays using endothelial cells and blocking antibodies against CLMP.
- Immunohistochemistry and flow cytometry were employed to quantify CLMP expression and immune cell infiltration.
Main Results:
- CLMP was identified as a cell trafficking molecule upregulated in inflammatory conditions and on endothelial cells in active MS lesions.
- Increased frequency of CLMP-expressing B lymphocytes and monocytes was observed in MS patients.
- Blocking CLMP significantly reduced immune cell migration across endothelial barriers in vitro, with CLMP+ immune cells found in MS brain lesions.
Conclusions:
- CLMP functions as an adhesion molecule facilitating immune cell entry into the CNS during neuroinflammation in MS.
- CLMP represents a potential therapeutic target for neuroinflammatory conditions like MS.
