Oral Presentation 29th Annual Lorne Proteomics Symposium 2024

Do end-of-life events perturb the peptide landscape of transplant donor tissues? (#24)

AKM Muraduzzaman 1 , Ifrah Dini 1 , Asolina Braun 1 , Rochelle Ayala 1 , Shanzhou Chung 1 , Patricia Illing 1 , Anthony Purcell 1 , Nicole Mifsud 1
  1. Infection and Immunity Program, Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia

Transplantation is the only curative option for patients with end stage diseases, traumatic injuries or metabolic disorders. Deceased donor organs are categorised into either donation by brain death (DBD) or donation by circulatory death (DCD). Brain death is accompanied by a catecholamine storm and a surge in proinflammatory cytokines and chemokines1 that provides a molecular switch for peptide generation via the immunoproteasome. Whereas circulatory death exposes donor organs to extended warm ischaemia2 and is associated with increased risk of delayed graft function3. Each end-of-life event poses a different tissue milieu that potentially perturbs the donor-derived self-peptide repertoire (i.e. immunopeptidome) presented at the cell surface by human leukocyte antigens (HLA). In this study, we explored the human immunopeptidome of transplantable organs (e.g. heart, lung, liver) from HLA-A*02:01-positive DBD and DCD donors. Briefly, <300 mg of tissue was used for immunoaffinity purification of peptide/HLA class I complexes, with the peptides isolated by RP-HPLC prior to analysis by LC-MS/MS on a Bruker timsTOF Pro2. Data was searched with PEAKS online software against the Homo sapiens UniProt database. Matched tissue-specific proteomic data was also examined. Analysis of the HLA-A*02:01-restricted immunopeptidome identified both tissue-specific and commonly expressed peptides within the same donor, as well as across all donors. A total of 19,639 peptides were identified from the heart (3 DBD, 1 DCD), 23,741 peptides from the lungs (2 DBD), and 24,290 peptides from liver tissue (2 DBD, 1 DCD). No differences were observed for peptide quantity, but distinct peptide landscapes were detected with only 289 heart and 382 liver peptides shared between DBD and DCD, as well as longer peptides and lower binding affinities in DCD. Post-translational modifications revealed DBD had >90% oxidation and cysteinylation, whereas DCD had >40% acetylation. Proteomics analysis showed >100 differentially expressed genes between DBD and DCD. This information provides a greater understanding of the influence of end-of-life events on the peptide repertoire across transplant donor categories.

 

  1. Watts, R. P., O. Thom, and J. F. Fraser. 2013. Inflammatory signalling associated with brain dead organ donation: from brain injury to brain stem death and posttransplant ischaemia reperfusion injury. J Transplant 2013: 521369
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  3. Gavriilidis, P., and N. G. Inston. 2020. Recipient and allograft survival following donation after circulatory death versus donation after brain death for renal transplantation: A systematic review and meta-analysis. Transplant Rev (Orlando) 34: 100563.