Molecular Role of Bruton’s Tyrosine Kinase (BTK) in NLRP3 Inflammasome Activation

• Applicant: Professor Alexander Weber, Ph.D.
• Subject Area: Immunology ; Cell Biology
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 414795436

• Final Report Year: 2023

Final Report Abstract

The NLRP3 inflammasome has emerged a critical multi-protein complex formed upon exogenous and endogenous (sterile) insults during infection, tissue damage or cellular stress and its assembly has been considered a key process in initiating inflammation. For example, multiple diseases in humans, ranging from Staphylococcal infections to diabetes to ischemic stroke or heart attack, have been linked to the NLRP3 inflammasome. The elucidation of (i) its molecular mechanism of action, (ii) regulatory molecules; and (iii) pharmacological inhibitors are key challenges in immunology and inflammation research at current. We identified the well-known signaling molecule Bruton’s Tyrosine Kinase (BTK) to unexpectedly play a critical role in NLRP3 inflammasome activation in both mice and humans, offering the unique opportunity to target the NLRP3 inflammasome at the level of a well-known pharmacological target, BTK, via efficacious and well-tolerated FDA-approved inhibitors, e.g. ibrutinib. Here we addressed the following questions: 1) What is the mechanistic molecular and cellular role of BTK in inflammasome activation? 2) What is the in vivo significance and therapeutic potential of BTK’s involvement in inflammasome activation in sterile and non-sterile inflammatory states involving the NLRP3 inflammasome? We here identified TLR-Syk signaling to lead to BTK activation and co-localization with NLRP3. Moreover, NLRP3 emerged as a direct target of BTK, being phosphorylated at four consecutive tyrosine residues in a linker that direct NLRP3 trafficking and oligomerization by altering NLRP3 charge, trafficking and oligomerization. Moreover, we found intriguing cell-specific roles of BTK in vivo and ex vivo. Altogether, this projects provides a deeper insight into the molecular properties and translational tractability of BTK as a targetable NLRP3 regulator.

Publications

• Recent insights into the regulatory networks of NLRP3 inflammasome activation. Journal of Cell Science, 133(23).
  Weber, Alexander N. R.; Bittner, Zsófia A.; Shankar, Sangeetha; Liu, Xiao; Chang, Tzu-Hsuan; Jin, Tengchuan & Tapia-Abellán, Ana
  
• BTK operates a phospho-tyrosine switch to regulate NLRP3 inflammasome activity. Journal of Experimental Medicine, 218(11).
  Bittner, Zsófia Agnes; Liu, Xiao; Mateo, Tortola Maria; Tapia-Abellán, Ana; Shankar, Sangeetha; Andreeva, Liudmila; Mangan, Matthew; Spalinger, Marianne; Kalbacher, Hubert; Düwell, Peter; Lovotti, Marta; Bosch, Karlotta; Dickhöfer, Sabine; Marcu, Ana; Stevanović, Stefan; Herster, Franziska; Cardona, Gloria Yamel; Chang, Tzu-Hsuan; Bork, Francesca ... & Weber, Alexander N.R.
  
• Targeting the NLRP3 Inflammasome via BTK. Frontiers in Cell and Developmental Biology, 9.
  Weber, Alexander N. R.
  
• The NLRP3 inflammasome drives inflammation in ischemia/reperfusion injury after transient middle cerebral artery occlusion in mice. Brain, Behavior, and Immunity, 92, 221-231.
  Franke, Maximilian; Bieber, Michael; Kraft, Peter; Weber, Alexander N.R.; Stoll, Guido & Schuhmann, Michael K.
  
• NLRP3 Phospho-residue Mapping by Phospho Dot Blots. Methods in Molecular Biology, 93-103. Springer US.
  Shankar, Sangeetha; Bittner, Zsofia A. & Weber, Alexander N. R.
  
• Delayed NLRP3 inflammasome inhibition ameliorates subacute stroke progression in mice. Journal of Neuroinflammation, 20(1).
  Bellut, Maximilian; Bieber, Michael; Kraft, Peter; Weber, Alexander N. R.; Stoll, Guido & Schuhmann, Michael K.