title: Serglycin determines secretory granule repertoire and regulates natural killer cell and cytotoxic T lymphocyte cytotoxicity.
abstract: The anionic proteoglycan serglycin is a major constituent of secretory granules in cytotoxic T lymphocyte (CTL)/natural killer (NK) cells, and is proposed to promote the safe storage of the mostly cationic granule toxins, granzymes and perforin. Despite the extensive defects of mast cell function reported in serglycin gene-disrupted mice, no comprehensive study of physiologically relevant CTL/NK cell populations has been reported. We show that the cytotoxicity of serglycin-deficient CTL and NK cells is severely compromised but can be partly compensated in both cell types when they become activated. Reduced intracellular granzyme B levels were noted, particularly in CD27(+) CD11b(+) mature NK cells, whereas serglycin(-/-) TCR-transgenic (OTI) CD8 T cells also had reduced perforin stores. Culture supernatants from serglycin(-/-) OTI T cells and interleukin-2-activated NK contained increased granzyme B, linking reduced storage with heightened export. By contrast, granzyme A was not significantly reduced in cells lacking serglycin, indicating differentially regulated trafficking and/or storage for the two granzymes. A quantitative analysis of different granule classes by transmission electronmicroscopy showed a selective loss of dense-core granules in serglycin(-/-) CD8(+) CTLs, although other granule types were maintained quantitatively. The findings of the present study show that serglycin plays a critical role in the maturation of dense-core cytotoxic granules in cytotoxic lymphocytes and the trafficking and storage of perforin and granzyme B, whereas granzyme A is unaffected. The skewed retention of cytotoxic effector molecules markedly reduces CTL/NK cell cytotoxicity, although this is partly compensated for as a result of activating the cells by physiological means.
authors.affiliation: Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors.forename: Vivien R
authors.initials: VR
authors.lastname: Sutton
authors.affiliation: Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors.forename: Amelia J
authors.initials: AJ
authors.lastname: Brennan
authors.affiliation: Microscopy and Histology, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors.forename: Sarah
authors.initials: S
authors.lastname: Ellis
authors.affiliation: Microscopy and Histology, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors.forename: Jill
authors.initials: J
authors.lastname: Danne
authors.affiliation: Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors.forename: Kevin
authors.initials: K
authors.lastname: Thia
authors.affiliation: Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors.forename: Misty R
authors.initials: MR
authors.lastname: Jenkins
authors.affiliation: Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors.forename: Ilia
authors.initials: I
authors.lastname: Voskoboinik
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, Sweden.|Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Pejler
authors.affiliation: Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.|The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Victoria, Australia.
authors.forename: Ricky W
authors.initials: RW
authors.lastname: Johnstone
authors.affiliation: Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Andrews
authors.affiliation: Cancer Cell Death/Killer Cell Biology Laboratories, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.|The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Victoria, Australia.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Trapani
mesh_terms: D000818:Animals; D039481:CD11b Antigen / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology; D002469:Cell Separation; D002478:Cells, Cultured; D003433:Crosses, Genetic; D005260:Female; D005434:Flow Cytometry; D053804:Granzymes / Q000378:metabolism; D007694:Killer Cells, Natural / Q000378:metabolism*; D008297:Male; D008407:Mast Cells / Q000166:cytology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D046529:Microscopy, Electron, Transmission; D052899:Pore Forming Cytotoxic Proteins / Q000378:metabolism; D011509:Proteoglycans / Q000378:metabolism*; D059748:Proteolysis; D022142:Secretory Vesicles / Q000378:metabolism*; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology*; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7 / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000378:metabolism*
chemical_list: D039481:CD11b Antigen; D052899:Pore Forming Cytotoxic Proteins; D011509:Proteoglycans; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D033921:Vesicular Transport Proteins; C483886:perforin, mouse; C075430:serglycin; D053804:Granzymes; C000597315:granzyme A, mouse
keywords: cytotoxic T lymphocyte; granzymes; natural killer cell; perforin; serglycin