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 August 1, 2018; First published July 16, 2018
Citation Information: J Clin Invest. 2018;128(8):3490-3503. https://doi.org/10.1172/JCI94524.
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Categories: 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 1

Existence of a P2X7R/NLRP3 pathway within human CD4+ T cells.

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Existence of a P2X7R/NLRP3 pathway within human CD4+ T cells. (A) P2X7R ...
(A) P2X7R and NLRP3 immunoprecipitation (IP) in human CD4+ T cells. Expression of NLRP3 (top blot) and P2X7R (bottom blot) is shown. Lane 1: Total protein. Lane 2: IP with NLRP3 Ab. Lane 3: IP with P2X7R Ab. Lane 4: IP with Ab alone (NLRP3 and P2X7R). Lane 5: IP with control IgG (for NLRP3 Ab in top blot, for P2X7R Ab in bottom blot). The experiment was run in triplicate (representative blot shown). (B and C) Confocal microscopy analysis (B, scale bar: 5 μm, ×100 original magnification; C, scale bars: 20 μm, ×40 original magnification) depicting baseline colocalization of P2X7R (green) and NLRP3 (red) in human CD4+ T cells. Cells were stained with DAPI (blue) and immunolabeled with anti-P2X7R (green) and anti-NLRP3 Abs (red) (n = 3). (D–F) Bar graphs depicting expression of NLRP3 mRNA by qRT-PCR (D), and protein by flow cytometry (E) and ELISA (F), evaluated in human CD4+ T cells activated with benzoyl ATP (BzATP) and treated with CE-224,535, a P2X7R inhibitor. Experiments were run in duplicate (n = 5). (G) Bar graph representing expression of NLRP3 on human CD4+P2X7R+ cells analyzed by flow cytometry upon BzATP stimulation (n = 5). (H) Representative flow dot plots of NLRP3 expression upon gating on human BzATP-stimulated CD4+P2X7R+ cells. (I) Confocal analysis (scale bar: 5 μm; ×100 original magnification) depicting colocalization of P2X7R (green) and NLRP3 (red) in CD4+ T cells upon in vitro stimulation of P2X7R with BzATP (n = 3). (J–M) Bar graphs comparing expression of NLRP3 downstream signaling Th2-related factors IL-4 (J), IRF4 (K), GATA-3 (L), and IL-10 (M) by qRT-PCR using mRNA isolated from human CD4+ T cells activated with BzATP and treated with the P2X7R inhibitor CE-224,535. Experiments were run in triplicate (n = 5). Data are expressed as mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001; 1-way ANOVA with Bonferroni’s post hoc test or Student’s t test. mRNA expression was normalized to β-actin (ACTB).