Abstract
Inflammation is required for host defense as well as wound healing but wields enormous destructive potential, highlighting the need for multiple ‘checks and balances’ [1]. The NLRP3 inflammasome, a pivotal molecular machine for the maturation of IL-1 family pro-inflammatory cytokines [1], is controlled by accessory proteins [2, 3], post-translational modifications [4, 5], localization [6, 7] and oligomerization [8]. How these factors act in concert is unclear. We show that the established drug target NLRP3 regulator, Bruton’s Tyrosine Kinase (BTK) [2, 9], integrates these levels of regulation to boost inflammasome activity: by directly phosphorylating four conserved tyrosine residues in a polybasic NLRP3 PYD-NACHT domain linker region, BTK weakens the interaction of NLRP3 with Golgi phospholipids and localization. BTK activity also promotes NLRP3 oligomerization and subsequent formation of inflammasomes. As NLRP3 tyrosine modification impacted on IL-1β release, we propose a novel BTK- and charge-mediated molecular phospho-switch to decisively regulate NLRP3 activity. Collectively, our study highlights BTK as a ‘multi-layer regulator’ of the inflammasome and NLRP3 multi-tyrosine phosphorylation as a therapeutic target for restricting excess inflammation.
Footnotes
Funding The study was supported by the Else-Kröner-Fresenius Stiftung (to ANRW), the Deutsche Forschungsgemeinschaft (German Research Foundation, DFG) grants CRC TR156 “The skin as an immune sensor and effector organ – Orchestrating local and systemic immunity” (to ZSB, FH and ANRW) and We-4195/15-1 (to ANRW), University Hospital Tübingen (Fortüne Grant 2310-0-0 to XL and ANRW), IFM Therapeutics (to ANRW), the “E-rare” program of the European Union, managed by the DFG, grant code GR1617/14-1/iPAD (to BG), and the “Netzwerke Seltener Erkrankungen” of the German Ministry of Education and Research (BMBF, GAIN_ 01GM1910A, to BG) and the Damon Runyon Cancer Research Foundation (to LA). Infrastructural funding was provided by the University of Tübingen, the University Hospital Tübingen and the DFG Clusters of Excellence “iFIT – Image-Guided and Functionally Instructed Tumor Therapies” (EXC 2180, to AW), “CMFI – Controlling Microbes to Fight Infection (EXC 2124, to AW), “CIBSS – Centre for Integrative Signalling Studies” (EXC 2189, to BG) and “RESIST – Resolving Infection Susceptibility” (EXC 2155, to BG). Gefördert durch die Deutsche Forschungsgemeinschaft (DFG) im Rahmen der Exzellenzstrategie des Bundes und der Länder - EXC 2180 (390900677), EXC 2124, EXC 2189 (390939984) and EXC 2155 (39087428).
Abbreviations
- AIM2
- Interferon-inducible protein absent in melanoma 2
- ASC
- Apoptosis-associated speck-like protein containing a Caspase activation and recruitment domain (CARD)
- BMDM
- bone marrow-derived macrophages
- BTK
- Bruton’s Tyrosine Kinase
- FDA
- Food and Drug Administration
- CAPS
- Cryopyrin-associated periodic syndrome
- GM-CSF
- Granulocyte-macrophage colony-stimulating factor
- HD
- healthy (blood) donor
- HEK
- human embryonic kidney
- IFN
- Interferon
- IL
- Interleukin
- KD
- kinase-dead
- LPS
- Lipopolysaccharide
- LRR
- leucine-rich repeat
- NEK7
- NIMA related kinase 7
- NACHT
- NAIP, CIITA, HET-E and TEP1
- NLR
- Nod-like receptor
- NLRP3
- NACHT, LRR and PYD domains-containing protein 3
- PBMC
- peripheral blood mononuclear cell
- PH
- Pleckstrin homology
- PtdIns4P
- phosphatidylinositol-4-phosphate
- PMA
- Phorbol-12-myristate-13-acetate
- p-Y
- phospho-tyrosine
- PYD
- Pyrin domain
- SH
- Src homology
- TGN
- trans-Golgi network
- TH
- Tec homology
- TLR
- Toll-like receptor
- TNF
- Tumor necrosis factor
- XLA
- X-linked agammaglobulinemia