title: Acid Sphingomyelinase-Derived Ceramide Regulates ICAM-1 Function during T Cell Transmigration across Brain Endothelial Cells.
abstract: Multiple sclerosis (MS) is a chronic demyelinating disorder of the CNS characterized by immune cell infiltration across the brain vasculature into the brain, a process not yet fully understood. We previously demonstrated that the sphingolipid metabolism is altered in MS lesions. In particular, acid sphingomyelinase (ASM), a critical enzyme in the production of the bioactive lipid ceramide, is involved in the pathogenesis of MS; however, its role in the brain vasculature remains unknown. Transmigration of T lymphocytes is highly dependent on adhesion molecules in the vasculature such as intercellular adhesion molecule-1 (ICAM-1). In this article, we hypothesize that ASM controls T cell migration by regulating ICAM-1 function. To study the role of endothelial ASM in transmigration, we generated brain endothelial cells lacking ASM activity using a lentiviral shRNA approach. Interestingly, although ICAM-1 expression was increased in cells lacking ASM activity, we measured a significant decrease in T lymphocyte adhesion and consequently transmigration both in static and under flow conditions. As an underlying mechanism, we revealed that upon lack of endothelial ASM activity, the phosphorylation of ezrin was perturbed as well as the interaction between filamin and ICAM-1 upon ICAM-1 clustering. Functionally this resulted in reduced microvilli formation and impaired transendothelial migration of T cells. In conclusion, in this article, we show that ASM coordinates ICAM-1 function in brain endothelial cells by regulating its interaction with filamin and phosphorylation of ezrin. The understanding of these underlying mechanisms of T lymphocyte transmigration is of great value to develop new strategies against MS lesion formation.
authors.affiliation: Department of Molecular Cell Biology and Immunology, Neuroscience Campus Amsterdam, VU University Medical Center, 1007 MB Amsterdam, the Netherlands;
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Lopes Pinheiro
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, 1066 CX Amsterdam, the Netherlands; and.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Kroon
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, 1066 CX Amsterdam, the Netherlands; and.
authors.forename: Mark
authors.initials: M
authors.lastname: Hoogenboezem
authors.affiliation: Department of Pediatric Oncology/Hematology, Sophia Children's Hospital, Erasmus University Medical Center, 3015 GJ Rotterdam, the Netherlands.
authors.forename: Dirk
authors.identifier: http://orcid.org/0000-0002-6386-8187
authors.initials: D
authors.lastname: Geerts
authors.affiliation: Department of Molecular Cell Biology and Immunology, Neuroscience Campus Amsterdam, VU University Medical Center, 1007 MB Amsterdam, the Netherlands;
authors.forename: Bert
authors.initials: B
authors.lastname: van Het Hof
authors.affiliation: Department of Molecular Cell Biology and Immunology, Neuroscience Campus Amsterdam, VU University Medical Center, 1007 MB Amsterdam, the Netherlands;
authors.forename: Susanne M A
authors.initials: SM
authors.lastname: van der Pol
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, 1066 CX Amsterdam, the Netherlands; and.
authors.forename: Jaap D
authors.initials: JD
authors.lastname: van Buul
authors.affiliation: Department of Molecular Cell Biology and Immunology, Neuroscience Campus Amsterdam, VU University Medical Center, 1007 MB Amsterdam, the Netherlands; he.devries@vumc.nl.
authors.forename: Helga E
authors.initials: HE
authors.lastname: de Vries
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D002448:Cell Adhesion / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D002518:Ceramides / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000378:metabolism; D042783:Endothelial Cells / Q000276:immunology / Q000378:metabolism; D005260:Female; D064448:Filamins / Q000378:metabolism; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000276:immunology; D010766:Phosphorylation / Q000235:genetics; D013108:Sphingomyelin Phosphodiesterase / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology*; D057705:Transendothelial and Transepithelial Migration / Q000276:immunology*; D000099149:Ezrin
chemical_list: D002518:Ceramides; D003598:Cytoskeletal Proteins; D064448:Filamins; D018799:Intercellular Adhesion Molecule-1; D013108:Sphingomyelin Phosphodiesterase; D000099149:Ezrin