<em>PIG</em> Genes and ULBP2 Drive a Novel Mechanism of NK-Cell Mediated Cytotoxicity — ASN Events
  1. Schedule
  2. Poster Session Two
  3. PIG Genes and ULBP2 Drive a Novel Mechanism of NK-Cell Mediated Cytotoxicity

PIG Genes and ULBP2 Drive a Novel Mechanism of NK-Cell Mediated Cytotoxicity (#204)

Simon Nicoletti 1 2 , Louise Rethacker 2 3 , Vincent Guitard 2 3 , Hugo Romero 2 , Marie-Eve Lalonde 4 , Marc Sasseville 4 , Aissa Benyoucef 2 , Christine Gadoury 4 , Khampoun Sayasith 2 , Silvia Selleri 2 , Aurélien B.L. Colamartino 2 , Kathie Béland 2 , Tapan Agnihotri 2 , Tammy-Lynn Tremblay 4 , Isabelle Turcotte 3 , Isabelle Louis 2 , Rebecca A. Marsh 5 6 , Yenan T. Bryceson 7 , Catherine A. Blish 8 , Marie Passet 9 10 , Jennifer J. Hill 4 11 , Emmanuelle Clappier 9 10 , Jean-Sebastien Joyal 2 12 , Nicolas Boissel 13 , Richard Marcotte 3 4 , Olivier Hermine 1 , Elie Haddad 2 3 12
  1. Imagine Institute, INSERM U1163, University of Paris, Necker University Hospital, Paris, France, Paris
  2. Centre de Recherche Azrieli du CHU Sainte-Justine, University of Montreal, Montreal, QC, Canada
  3. Department of Microbiology, Immunology and Infectious Diseases, University of Montreal, Montreal, QC, Canada
  4. Human Health Therapeutics Research Centre, National Research Council Canada, Montreal and Ottawa, Canada
  5. Cincinnati Children's Hospital, University of Cincinnati, Cincinnati, OH, USA
  6. Pharming Healthcare Inc, Warren, NJ, USA
  7. Department of Medicine Hudddinge, Center for Hematology and Regenerative Medicine, Karolinska Institute, Stockholm, Sweden
  8. Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
  9. Université Paris Cité, Inserm U944, Institut de Recherche Saint-Louis, Paris, France
  10. Service d’Hématologie biologique, Hôpital Saint-Louis, AP-HP, Paris, France
  11. Ottawa Institute for Systems Biology, Ottawa, ON, Canada
  12. Department of Pediatrics, University of Montreal, Montreal, QC, Canada
  13. Hôpital Saint-Louis, APHP, Institut de Recherche Saint-Louis, Université Paris Cité, Paris, France

NK-cell cytotoxicity relies on contact-dependent and -independent mechanisms. Contact-dependent cytotoxicity is known to involve either granule exocytosis (a rapid process) or death receptors (DRs) canonical pathways, but existence of alternative killing mechanisms has been suggested. A strong understanding of these killing properties is important for therapeutic strategies that rely on NK cells, such as allogeneic hematopoietic stem cell transplantation, chimeric antigen receptor (CAR) T- and NK- cells, or cellular engagers for T or NK cells with tumor cells.

We used B-ALL leukemic cell lines and primary cells partially resistant to canonical NK-cell killing to study alternative killing pathways. We found that NK cells efficiently killed these presumed resistant target cells after a prolonged (>12h) co-culture through a contact-dependent mechanism. Using NK cells from patients with perforin (PRF1) expression or degranulation (UNC13D) defects, combined with target cells expressing a dominant-negative FADD conferring a stable resistance to DRs-mediated apoptosis, we demonstrated that this delayed killing involved a novel contact-dependent mechanism that differs from both the canonical granule exocytosis and DRs pathways. Molecularly, genome-wide CRISPR screens and a surfaceome analysis on target cells identified the GPI-anchored synthesis pathway and ULBP2 expression to regulate this new killing mechanism. ULBP2 expression was reduced in resistant target cells and its overexpression could restore NK-cell sensitivity with no contribution of the granule exocytosis pathway. ULBP2 expression also correlated with improved overall survival in a large cohort of adult patients with B-ALL leukemia, demonstrating the clinical relevance of this new killing mechanism.

Overall, our work demonstrates that NK cells can use multiple mechanisms to kill target cells including a novel contact-dependent, degranulation- and death receptors-independent pathway. This process relied on a distinctive low NK-cell metabolic profile, supporting a model of metabolic flexibility among killing mechanisms. Finally, it revealed anchored proteins and ULBP2 as potential targets for its modulation.