Bruton tyrosine kinase deficiency augments NLRP3 inflammasome activation and causes IL-1β–mediated colitis
Liming Mao, … , Adrian Wiestner, Warren Strober
Liming Mao, … , Adrian Wiestner, Warren Strober
Published January 2, 2020
Citation Information: J Clin Invest. 2020;130(4):1793-1807. https://doi.org/10.1172/JCI128322.
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Research Article Gastroenterology

Bruton tyrosine kinase deficiency augments NLRP3 inflammasome activation and causes IL-1β–mediated colitis

Abstract

Bruton tyrosine kinase (BTK) is present in a wide variety of cells and may thus have important non–B cell functions. Here, we explored the function of this kinase in macrophages with studies of its regulation of the NLR family, pyrin domain–containing 3 (NLRP3) inflammasome. We found that bone marrow–derived macrophages (BMDMs) from BTK-deficient mice or monocytes from patients with X-linked agammaglobulinemia (XLA) exhibited increased NLRP3 inflammasome activity; this was also the case for BMDMs exposed to low doses of BTK inhibitors such as ibrutinib and for monocytes from patients with chronic lymphocytic leukemia being treated with ibrutinib. In mechanistic studies, we found that BTK bound to NLRP3 during the priming phase of inflammasome activation and, in doing so, inhibited LPS- and nigericin-induced assembly of the NLRP3 inflammasome during the activation phase of inflammasome activation. This inhibitory effect was caused by BTK inhibition of protein phosphatase 2A–mediated (PP2A-mediated) dephosphorylation of Ser5 in the pyrin domain of NLRP3. Finally, we show that BTK-deficient mice were subject to severe experimental colitis and that such colitis was normalized by administration of anti–IL-β or anakinra, an inhibitor of IL-1β signaling. Together, these studies strongly suggest that BTK functions as a physiologic inhibitor of NLRP3 inflammasome activation and explain why patients with XLA are prone to develop Crohn’s disease.

Authors

Liming Mao, Atsushi Kitani, Eitaro Hiejima, Kim Montgomery-Recht, Wenchang Zhou, Ivan Fuss, Adrian Wiestner, Warren Strober

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Figure 3

BTK interacts with the NLRP3 pyrin and NATCH domains via its PH and PTK domains.

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BTK interacts with the NLRP3 pyrin and NATCH domains via its PH and PTK ...
(A) HEK293T cells were transfected with plasmids expressing a full-length NLRP3 construct as well as one of various BTK constructs. After 24 hours, the cells were lysed and the lysates subjected to IP and WB. (B) HEK293T cells were transfected with plasmids expressing a full-length NLRP3 construct as well as constructs expressing the full-length or PTK domain of BTK. After 24 hours, the cells were lysed and lysates subjected to IP and WB. (C) Conserved domains of mouse NLRP3 were analyzed, and constructs containing the various domains were generated as indicated. (D) HEK293T cells were transfected with plasmids expressing a full-length BTK construct as well as one of various NLRP3 constructs. After 24 hours, the cells were lysed and lysates subjected to IP and WB. (E) HEK293T cells were transfected with plasmids expressing the NLRP3 pyrin domain with or without cotransfection of a construct expressing a full-length BTK construct. After 24 hours, the cells were lysed and lysates subjected to IP and WB. Data are representative of 2 independent experiments.