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Updated: May 10, 2026
Detection of Inflammasome Activation and Pyroptotic Cell Death in Murine Bone Marrow-derived Macrophages
Published on: May 21, 2018
TH5487 specifically targets NLRP3 in FCAS patients resistant to MCC950
Abstract:
The NLRP3 inflammasome plays a central role in innate immunity and is activated in response to mitochondrial dysfunction and oxidized DNA. Here, we demonstrate that repurposed small-molecule inhibitors originally developed for DNA glycosylases, TH5487 and SU0268, potently inhibit NLRP3 activation ex vivo in human Peripheral Blood Mononuclear Cells (PBMCs) with IC 50 of 1.62 µM and 3.24 µM, respectively. We show that these inhibitors prevent mitochondrial localization of NLRP3 and directly block inflammasome assembly. They also reshape the immune landscape decreasing IL-1β, while increasing IFN-β. Structural and biophysical analyses reveal a two-site DNA binding model in which NLRP3 engages oxidized DNA with a KD1 of 0.268 nM and KD2 3.02 nM. Importantly, these inhibitors block IL-1β secretion in L353P Familial Cold Autoinflammatory Syndrome (FCAS) patient PBMCs where MCC950 fails, demonstrating the therapeutic potential for inflammasome-driven diseases. Together, our findings reveal a novel druggable mechanism of inflammasome inhibition through interference with oxidized DNA sensing and localization, offering new opportunities for treatment of chronic inflammatory disorders.
Insights
Repurposed DNA glycosylase inhibitors TH5487 and SU0268 potently block NLRP3 inflammasome activation by preventing mitochondrial localization and oxidized DNA binding. These compounds offer therapeutic potential for inflammasome-driven diseases.
Area of Science:
- Immunology
- Molecular Biology
- Drug Discovery
Background:
- The NLRP3 inflammasome is crucial for innate immunity.
- NLRP3 activation is triggered by mitochondrial dysfunction and oxidized DNA.
- Dysregulated NLRP3 inflammasome activity drives autoinflammatory diseases.
Purpose of the Study:
- To identify novel inhibitors of NLRP3 inflammasome activation.
- To investigate the mechanism of NLRP3 inhibition by small molecules.
- To explore therapeutic potential in inflammasome-driven conditions.
Main Methods:
- Ex vivo inhibition assays in human Peripheral Blood Mononuclear Cells (PBMCs).
- Biophysical and structural analyses of NLRP3-DNA interactions.
- Assessment of cytokine profiles (IL-1β, IFN-β).
Main Results:
- TH5487 and SU0268 potently inhibit NLRP3 activation (IC50s 1.62 µM and 3.24 µM).
- Inhibitors prevent NLRP3 mitochondrial localization and inflammasome assembly.
- NLRP3 binds oxidized DNA via a two-site mechanism (KD1=0.268 nM, KD2=3.02 nM).
- Inhibitors decrease IL-1β and increase IFN-β production.
- Effective inhibition in Familial Cold Autoinflammatory Syndrome patient cells where MCC950 failed.
Conclusions:
- Repurposed DNA glycosylase inhibitors target NLRP3 inflammasome activation.
- Interference with oxidized DNA sensing is a novel inhibition mechanism.
- These inhibitors demonstrate therapeutic promise for inflammasome-mediated diseases.
