title: Hypotonicity induces L-selectin shedding in human neutrophils.
abstract: Expression levels of adhesion molecules on neutrophils are affected under various conditions, including ischemia, possibly because of associated increases in cell volume. We examined the effects of cell swelling in hypotonic media on the level of L-selectin (CD62L) and beta(2)-integrin (CD18) on human neutrophils. In hypotonic media, neutrophils shed L-selectin. The shedding was greatly reduced by 30 microM RO31-9790, the metalloprotease (sheddase) inhibitor. Hypotonicity-induced L-selectin shedding was also time and tonicity dependent. Decreasing tonicity caused increased shedding. In 0.6x medium (0.6x the normal tonicity of 300 mosmol/kgH(2)O), shedding increased over a 2-h period, after which >70% of the neutrophils had lost L-selectin. In contrast to L-selectin, the level of beta(2)-integrin on the neutrophil surface was not significantly affected. Thus L-selectin shedding, which occurs on neutrophil activation and is usually accompanied by beta(2)-integrin upregulation, was selectively induced by hypotonicity without a corresponding effect on beta(2)-integrin.
authors.affiliation: Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642, USA.
authors.forename: N K
authors.initials: NK
authors.lastname: Kaba
authors.forename: P A
authors.initials: PA
authors.lastname: Knauf
mesh_terms: D018821:CD18 Antigens / Q000378:metabolism; D006801:Humans; D007038:Hypotonic Solutions / Q000494:pharmacology*; D019041:L-Selectin / Q000378:metabolism*; D008666:Metalloendopeptidases / Q000378:metabolism; D008833:Microcirculation / Q000276:immunology; D009504:Neutrophils / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014882:Water-Electrolyte Balance / Q000502:physiology*
chemical_list: D018821:CD18 Antigens; D007038:Hypotonic Solutions; D014409:Tumor Necrosis Factor-alpha; D019041:L-Selectin; D008666:Metalloendopeptidases