title: Properties and functions of lactosylceramide from mouse neutrophils.
abstract: Lactosylceramide (LacCer), which is essential for many cellular processes, is highly expressed on the plasma membranes of human neutrophils and mediates innate immune functions. Less is known, however, about the properties and biological functions of LacCer in mouse neutrophils. This study therefore analyzed the properties of mouse neutrophil LacCer. LacCer was observed on the surface of these cells, with flow cytometry indicating that mouse neutrophil LacCer could be detected by the anti-LacCer mAb T5A7, but not by the anti-LacCer antibodies Huly-m13 and MEM-74. The molecular species of LacCer were nearly identical in mouse and human neutrophils, including C24:0 and C24:1 fatty acid chain-containing species, although the LacCer content in plasma membranes was ∼ 20-fold lower in mouse than in human neutrophils. Surface plasmon resonance analysis revealed that T5A7 bound to a lipid monolayer composed of LacCer, DOPC, cholesterol and sphingomyelin (molar ratio 0.1 : 10 : 10 : 1), whereas Huly-m13 did not. T5A7 induced neutrophil migration, which was abolished by inhibitors of Src-family kinases, PI-3 kinases, and trimeric G (o/i) proteins. T5A7 also inhibited phagocytosis of non-opsonized zymosans by neutrophils. Taken together, these findings suggest that in mouse neutrophils, (i) LacCer is expressed as LacCer-enriched microdomains in cell surface plasma membranes, (ii) these microdomains are recognized by T5A7 but not by other known anti-LacCer antibodies and (iii) LacCer is involved in cell migration and phagocytosis.
authors.affiliation: Institute for Environmental and Gender-Specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka, Urayasu-shi, Chiba, Japan Laboratory for Biochemistry, Juntendo University, Faculty of Health Care and Nursing, Chiba, Japan Infection Control Nursing, Juntendo University Graduate School of Health Care and Nursing, Chiba, Japan iwabuchi@juntendo.ac.jp.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Iwabuchi
authors.affiliation: Institute for Environmental and Gender-Specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka, Urayasu-shi, Chiba, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Masuda
authors.affiliation: Division of Proteomics and Biomolecular Science, BioMedical Research Center, Tokyo, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Kaga
authors.affiliation: Institute for Environmental and Gender-Specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka, Urayasu-shi, Chiba, Japan Laboratory for Biochemistry, Juntendo University, Faculty of Health Care and Nursing, Chiba, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nakayama
authors.affiliation: Institute for Environmental and Gender-Specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka, Urayasu-shi, Chiba, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Matsumoto
authors.affiliation: Institute for Environmental and Gender-Specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka, Urayasu-shi, Chiba, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Iwahara
authors.affiliation: Institute for Environmental and Gender-Specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka, Urayasu-shi, Chiba, Japan.
authors.forename: Fumiko
authors.initials: F
authors.lastname: Yoshizaki
authors.affiliation: Institute for Environmental and Gender-Specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka, Urayasu-shi, Chiba, Japan.
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Tamaki
authors.affiliation: Lipid Biology Laboratory, RIKEN, Saitama, Japan Juntendo University Graduate School of Medicine, Tokyo, Japan.
authors.forename: Toshihide
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: Lipid Biology Laboratory, RIKEN, Saitama, Japan Juntendo University Graduate School of Medicine, Tokyo, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Hayakawa
authors.affiliation: Lipid Biology Laboratory, RIKEN, Saitama, Japan Juntendo University Graduate School of Medicine, Tokyo, Japan.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Ishii
authors.affiliation: Institute for Environmental and Gender-Specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka, Urayasu-shi, Chiba, Japan.
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Yanagida
authors.affiliation: Institute for Environmental and Gender-Specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka, Urayasu-shi, Chiba, Japan.
authors.forename: Hideoki
authors.initials: H
authors.lastname: Ogawa
authors.affiliation: Institute for Environmental and Gender-Specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka, Urayasu-shi, Chiba, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Takamori
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000937:Antigen-Antibody Reactions; D015703:Antigens, CD / Q000096:biosynthesis / Q000276:immunology* / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D064368:Healthy Volunteers; D006801:Humans; D007790:Lactosylceramides / Q000096:biosynthesis / Q000276:immunology* / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009504:Neutrophils / Q000737:chemistry* / Q000166:cytology / Q000276:immunology / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D007790:Lactosylceramides; C009744:CDw17 antigen; D002118:Calcium
keywords: chemotaxis; lactosylceramide; mouse neutrophils; phagocytosis