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Updated: May 16, 2026
Activation and Measurement of NLRP3 Inflammasome Activity Using IL-1β in Human Monocyte-derived Dendritic Cells
Published on: May 22, 2014
CLEC5A is critical for dengue virus-induced inflammasome activation in human macrophages
Ming-Fang Wu1, Szu-Ting Chen, An-Hang Yang
1Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan.
Abstract:
Persistent high fever is one of the most typical clinical symptoms in dengue virus (DV)-infected patients. However, the source of endogenous pyrogen (eg, IL-1β) and the signaling cascade leading to the activation of inflammasome and caspase-1, which are essential for IL-1β and IL-18 secretion, during dengue infection have not been elucidated yet. Macrophages can be polarized into distinct phenotypes under the influence of GM-CSF or M-CSF, denoted as GM-Mϕ and M-Mϕ, respectively. We found that DV induced high levels of IL-1β and IL-18 from GM-Mϕ (inflammatory macrophage) and caused cell death (pyroptosis), whereas M-Mϕ (resting macrophage) did not produce IL-1β and IL-18 on DV infection even with lipopolysaccharide priming. This observation demonstrates the distinct responses of GM-Mϕ and M-Mϕ to DV infection. Moreover, up-regulation of pro-IL-1β, pro-IL-18, and NLRP3 associated with caspase-1 activation was observed in DV-infected GM-Mϕ, whereas blockade of CLEC5A/MDL-1, a C-type lectin critical for dengue hemorrhagic fever and Japanese encephalitis virus infection, inhibits NLRP3 inflammasome activation and pyrotopsis in GM-Mϕ. Thus, DV can activate NLRP3 inflammasome via CLEC5A, and GM-Mϕ plays a more important role than M-Mϕ in the pathogenesis of DV infection.
Insights
Dengue virus (DV) triggers inflammatory macrophages (GM-Mϕ) to release fever-inducing cytokines (IL-1β, IL-18) and cause cell death. This NLRP3 inflammasome activation via CLEC5A is key in DV pathogenesis.
Area of Science:
- Immunology
- Virology
- Cell Biology
Background:
- Persistent high fever is a hallmark of dengue virus (DV) infection.
- The precise mechanisms and cellular sources of pyrogenic cytokines like IL-1β during DV infection remain unclear.
- Inflammasome activation is critical for IL-1β and IL-18 secretion.
Purpose of the Study:
- To elucidate the source of endogenous pyrogens and the signaling pathways involved in inflammasome activation during DV infection.
- To investigate the differential roles of macrophage polarization (GM-Mϕ vs. M-Mϕ) in DV pathogenesis.
- To identify key molecular players in DV-induced inflammasome activation.
Main Methods:
- Macrophage polarization using GM-CSF (GM-Mϕ) and M-CSF (M-Mϕ).
- DV infection of polarized macrophages.
- Measurement of IL-1β and IL-18 levels.
- Analysis of inflammasome components (NLRP3, caspase-1) and cell death (pyroptosis).
- Inhibition studies using CLEC5A/MDL-1 blockade.
Main Results:
- DV infection induced high levels of IL-1β and IL-18 and pyroptosis specifically in GM-Mϕ, not M-Mϕ.
- DV infection led to upregulation of pro-IL-1β, pro-IL-18, and NLRP3 with caspase-1 activation in GM-Mϕ.
- Blockade of CLEC5A/MDL-1 inhibited NLRP3 inflammasome activation and pyroptosis in DV-infected GM-Mϕ.
- GM-Mϕ demonstrated distinct responses to DV infection compared to M-Mϕ.
Conclusions:
- Dengue virus activates the NLRP3 inflammasome via the C-type lectin CLEC5A.
- GM-Mϕ, an inflammatory macrophage phenotype, plays a significant role in DV pathogenesis by producing pyrogenic cytokines and undergoing pyroptosis.
- M-Mϕ, a resting macrophage phenotype, does not contribute to pyrogen production during DV infection.
