Nature Communications (Jun 2023)

NBEAL2 deficiency in humans leads to low CTLA-4 expression in activated conventional T cells

  • Laure Delage,
  • Francesco Carbone,
  • Quentin Riller,
  • Jean-Luc Zachayus,
  • Erwan Kerbellec,
  • Armelle Buzy,
  • Marie-Claude Stolzenberg,
  • Marine Luka,
  • Camille de Cevins,
  • Georges Kalouche,
  • Rémi Favier,
  • Alizée Michel,
  • Sonia Meynier,
  • Aurélien Corneau,
  • Caroline Evrard,
  • Nathalie Neveux,
  • Sébastien Roudières,
  • Brieuc P. Pérot,
  • Mathieu Fusaro,
  • Christelle Lenoir,
  • Olivier Pellé,
  • Mélanie Parisot,
  • Marc Bras,
  • Sébastien Héritier,
  • Guy Leverger,
  • Anne-Sophie Korganow,
  • Capucine Picard,
  • Sylvain Latour,
  • Bénédicte Collet,
  • Alain Fischer,
  • Bénédicte Neven,
  • Aude Magérus,
  • Mickaël Ménager,
  • Benoit Pasquier,
  • Frédéric Rieux-Laucat

DOI
https://doi.org/10.1038/s41467-023-39295-7
Journal volume & issue
Vol. 14, no. 1
pp. 1 – 12

Abstract

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Abstract Loss of NBEAL2 function leads to grey platelet syndrome (GPS), a bleeding disorder characterized by macro-thrombocytopenia and α-granule-deficient platelets. A proportion of patients with GPS develop autoimmunity through an unknown mechanism, which might be related to the proteins NBEAL2 interacts with, specifically in immune cells. Here we show a comprehensive interactome of NBEAL2 in primary T cells, based on mass spectrometry identification of altogether 74 protein association partners. These include LRBA, a member of the same BEACH domain family as NBEAL2, recessive mutations of which cause autoimmunity and lymphocytic infiltration through defective CTLA-4 trafficking. Investigating the potential association between NBEAL2 and CTLA-4 signalling suggested by the mass spectrometry results, we confirm by co-immunoprecipitation that CTLA-4 and NBEAL2 interact with each other. Interestingly, NBEAL2 deficiency leads to low CTLA-4 expression in patient-derived effector T cells, while their regulatory T cells appear unaffected. Knocking-down NBEAL2 in healthy primary T cells recapitulates the low CTLA-4 expression observed in the T cells of GPS patients. Our results thus show that NBEAL2 is involved in the regulation of CTLA-4 expression in conventional T cells and provide a rationale for considering CTLA-4-immunoglobulin therapy in patients with GPS and autoimmune disease.