NLRP3 tyrosine phosphorylation is controlled by protein tyrosine phosphatase PTPN22
Marianne R. Spalinger, … , Gerhard Rogler, Michael Scharl
Marianne R. Spalinger, … , Gerhard Rogler, Michael Scharl
Published May 2, 2016; First published April 4, 2016
Citation Information: J Clin Invest. 2016;126(5):1783-1800. https://doi.org/10.1172/JCI83669.
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Research Article Gastroenterology Immunology

NLRP3 tyrosine phosphorylation is controlled by protein tyrosine phosphatase PTPN22

Abstract

Inflammasomes form as the result of the intracellular presence of danger-associated molecular patterns and mediate the release of active IL-1β, which influences a variety of inflammatory responses. Excessive inflammasome activation results in severe inflammatory conditions, but physiological IL-1β secretion is necessary for intestinal homeostasis. Here, we have described a mechanism of NLRP3 inflammasome regulation by tyrosine phosphorylation of NLRP3 at Tyr861. We demonstrated that protein tyrosine phosphatase non-receptor 22 (PTPN22), variants in which are associated with chronic inflammatory disorders, dephosphorylates NLRP3 upon inflammasome induction, allowing efficient NLRP3 activation and subsequent IL-1β release. In murine models, PTPN22 deficiency resulted in pronounced colitis, increased NLRP3 phosphorylation, but reduced levels of mature IL-1β. Conversely, patients with inflammatory bowel disease (IBD) that carried an autoimmunity-associated PTPN22 variant had increased IL-1β levels. Together, our results identify tyrosine phosphorylation as an important regulatory mechanism for NLRP3 that prevents aberrant inflammasome activation.

Authors

Marianne R. Spalinger, Stephanie Kasper, Claudia Gottier, Silvia Lang, Kirstin Atrott, Stephan R. Vavricka, Sylvie Scharl, Petrus M. Gutte, Markus G. Grütter, Hans-Dietmar Beer, Emmanuel Contassot, Andrew C. Chan, Xuezhi Dai, David J. Rawlings, Florian Mair, Burkhard Becher, Werner Falk, Michael Fried, Gerhard Rogler, Michael Scharl

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Figure 1

Knockdown of PTPN22 reduces IL-1β secretion.

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Knockdown of PTPN22 reduces IL-1β secretion. PTPN22 knockdown was induce...
PTPN22 knockdown was induced in THP-1 cells using lentiviral shRNA expression vectors. Cells were pretreated for 12 hours with upLPS before activation with MDP (100 ng/ml, 24 hours), MSU (150 ng/ml, 6 hours), TiO2 (150 ng/ml, 24 hours), SiO2 (150 ng/ml, 12 hours), or ATP (200 mM, 30 minutes). (A) Cell culture supernatants were analyzed for IL-1β secretion, LDH release, and IL-6 secretion by ELISA. (B) Cell lysates or supernatants were analyzed for caspase-1 (Casp-1), caspase-3 (Casp-3), IL-1β, NLRP3, ASC, and PTPN22 expression. Blots for IL-1β were run on the same gel but were discontinuous. Data are representative of 1 of at least 3 independent experiments with 3–5 replicas (n = 3–5; *P < 0.05, **P < 0.01; Newman-Keuls post hoc test). Numbers below the blots show results of densitometry (cleaved forms).