P2X7R mutation disrupts the NLRP3-mediated Th program and predicts poor cardiac allograft outcomes
Francesca D’Addio, … , Francesco Grigioni, Paolo Fiorina
Francesca D’Addio, … , Francesco Grigioni, Paolo Fiorina
Published July 16, 2018
Citation Information: J Clin Invest. 2018;128(8):3490-3503. https://doi.org/10.1172/JCI94524.
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Research Article Immunology Transplantation

P2X7R mutation disrupts the NLRP3-mediated Th program and predicts poor cardiac allograft outcomes

Abstract

Purinergic receptor-7 (P2X7R) signaling controls Th17 and Th1 generation/differentiation, while NOD-like receptor P3 (NLRP3) acts as a Th2 transcriptional factor. Here, we demonstrated the existence of a P2X7R/NLRP3 pathway in T cells that is dysregulated by a P2X7R intracellular region loss-of-function mutation, leading to NLRP3 displacement and to excessive Th17 generation due to abrogation of the NLRP3-mediated Th2 program. This ultimately resulted in poor outcomes in cardiac-transplanted patients carrying the mutant allele, who showed abnormal Th17 generation. Transient NLRP3 silencing in nonmutant T cells or overexpression in mutant T cells normalized the Th profile. Interestingly, IL-17 blockade reduced Th17 skewing of human T cells in vitro and abrogated the severe allograft vasculopathy and abnormal Th17 generation observed in preclinical models in which P2X7R was genetically deleted. This P2X7R intracellular region mutation thus impaired the modulatory effects of P2X7R on NLRP3 expression and function in T cells and led to NLRP3 dysregulation and Th17 skewing, delineating a high-risk group of cardiac-transplanted patients who may benefit from personalized therapy.

Authors

Francesca D’Addio, Andrea Vergani, Luciano Potena, Anna Maestroni, Vera Usuelli, Moufida Ben Nasr, Roberto Bassi, Sara Tezza, Sergio Dellepiane, Basset El Essawy, Maria Iascone, Attilio Iacovoni, Laura Borgese, Kaifeng Liu, Gary Visner, Sirano Dhe-Paganon, Domenico Corradi, Reza Abdi, Randall C. Starling, Franco Folli, Gian Vincenzo Zuccotti, Mohamed H. Sayegh, Peter S. Heeger, Anil Chandraker, Francesco Grigioni, Paolo Fiorina

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Figure 2

A C-terminal P2X7R mutation dysregulates NLRP3 expression and function in human CD4+ T cells.

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A C-terminal P2X7R mutation dysregulates NLRP3 expression and function i...
(A) A 3D representation of the full-length structure of P2X7R, highlighting the putative location of the P2X7R mutation in the C-terminal intracellular portion. (B and C) Quantification of P2X7R total protein (B, ELISA, n = 3) and of P2X7R mRNA (C, qRT-PCR, n = 10) on CD4+ T cells of carrier and noncarrier patients. Samples were run in duplicate (B) or in triplicate (C) and normalized to expression level of β-actin (ACTB). (D) Transcriptome profiling of immune-relevant genes (see also Supplemental Table 3) examined in CD4+ T cells of carrier and noncarrier cardiac-transplanted patients (n = 5). (E–G) Expression of NLRP3 mRNA using qRT-PCR (E) and NLRP3 protein using flow cytometry (F) and ELISA (G) in CD4+ T cells of carrier and noncarrier patients (n = 5). (H and I) Flow cytometric expression of NLRP3 on CD4+P2X7R+ cells of carrier patients stimulated with BzATP (n = 5). (J) Percentage of P2X7R+NLRP3+ cells of carrier and noncarrier patients analyzed by immunofluorescence (Figure 1C and Supplemental Figure 2G) (n = 3). (K) Confocal microscopy analysis (×100 original magnification) of P2X7R (green) and NLRP3 (red) coexpression in CD4+ T cells of carrier patients (n = 3). Scale bar: 5 μm. (L) Subcellular localization of NLRP3 in CD4+ T cells of carrier and of noncarrier patients (n = 3). (M and N) IL-4 (M) and IRF4 (N) gene expression detected after ChIP with NLRP3 antibody in CD4+ T cells. (n = 3). (O) Quantification of NLRP3 protein measured in CD4+ T cells treated with the ubiquitin/protease inhibitor MG132 (n = 3). Bars represent mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001; Student’s t test or 2-way ANOVA with Bonferroni’s post hoc test.