Sir Peter MacCallum Department of Oncology - Research Publications

Permanent URI for this collection

http://hdl.handle.net/11343/274

Filters

2013 - 2019 2 2020 - 2022 1
Reset filters

Settings
Statistics
Citations
Author: Brennan, Amelia Jayne × Author: Trapani, Joseph × Start date: 2010 × Type: Journal Article ×

Search Results

Now showing 1 - 3 of 3
  • Item
    No Preview Available
    Severely impaired CTL killing is a feature of the neurological disorder Niemann-Pick disease type C1
    Castiblanco, D ; Rudd-Schmidt, JA ; Noori, T ; Sutton, VR ; Hung, YH ; Flinsenberg, TWH ; Hodel, AW ; Young, ND ; Smith, N ; Bratkovic, D ; Peters, H ; Walterfang, M ; Trapani, JA ; Brennan, AJ ; Voskoboinik, I (AMER SOC HEMATOLOGY, 2022-03-24)
    Niemann-Pick disease type C1 (NP-C1) is a rare lysosomal storage disorder resulting from mutations in an endolysosomal cholesterol transporter, NPC1. Despite typically presenting with pronounced neurological manifestations, NP-C1 also resembles long-term congenital immunodeficiencies that arise from impairment of cytotoxic T lymphocyte (CTL) effector function. CTLs kill their targets through exocytosis of the contents of lysosome-like secretory cytotoxic granules (CGs) that store and ultimately release the essential pore-forming protein perforin and proapoptotic serine proteases, granzymes, into the synapse formed between the CTL and target cell. We discovered that NPC1 deficiency increases CG lipid burden, impairs autophagic flux through stalled trafficking of the transcription factor EB (TFEB), and dramatically reduces CTL cytotoxicity. Using a variety of immunological and cell biological techniques, we found that the cytotoxic defect arises specifically from impaired perforin pore formation. We demonstrated defects of CTL function of varying severity in patients with NP-C1, with the greatest losses of function associated with the most florid and/or earliest disease presentations. Remarkably, perforin function and CTL cytotoxicity were restored in vitro by promoting lipid clearance with therapeutic 2-hydroxypropyl-β-cyclodextrin; however, restoration of autophagy through TFEB overexpression was ineffective. Overall, our study revealed that NPC1 deficiency has a deleterious impact on CTL (but not natural killer cell) cytotoxicity that, in the long term, may predispose patients with NP-C1 to atypical infections and impaired immune surveillance more generally.
  • Item
    Thumbnail Image
    Serglycin determines secretory granule repertoire and regulates natural killer cell and cytotoxic T lymphocyte cytotoxicity
    Sutton, VR ; Brennan, AJ ; Ellis, S ; Danne, J ; Thia, K ; Jenkins, MR ; Voskoboinik, I ; Pejler, G ; Johnstone, RW ; Andrews, DM ; Trapani, JA (WILEY, 2016-03)
    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.
  • Item
    No Preview Available
    Defining the interaction of perforin with calcium and the phospholipid membrane
    Traore, DAK ; Brennan, AJ ; Law, RHP ; Dogovski, C ; Perugini, MA ; Lukoyanova, N ; Leung, EWW ; Norton, RS ; Lopez, JA ; Browne, KA ; Yagita, H ; Lloyd, GJ ; Ciccone, A ; Verschoor, S ; Trapani, JA ; Whisstock, JC ; Voskoboinik, I (PORTLAND PRESS LTD, 2013-12-15)
    Following its secretion from cytotoxic lymphocytes into the immune synapse, perforin binds to target cell membranes through its Ca(2+)-dependent C2 domain. Membrane-bound perforin then forms pores that allow passage of pro-apoptopic granzymes into the target cell. In the present study, structural and biochemical studies reveal that Ca(2+) binding triggers a conformational change in the C2 domain that permits four key hydrophobic residues to interact with the plasma membrane. However, in contrast with previous suggestions, these movements and membrane binding do not trigger irreversible conformational changes in the pore-forming MACPF (membrane attack complex/perforin-like) domain, indicating that subsequent monomer-monomer interactions at the membrane surface are required for perforin pore formation.