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Updated: Mar 29, 2026
Activation and Measurement of NLRP3 Inflammasome Activity Using IL-1β in Human Monocyte-derived Dendritic Cells
Published on: May 22, 2014
Posttranscriptional control of NLRP3 inflammasome activation in colonic macrophages
A A Filardy1, J He1, J Bennink2
1Mucosal Immunobiology Section, Laboratory of Molecular Immunology, NIAID, NIH, Bethesda, Maryland, USA.
Abstract:
Colonic macrophages (cMPs) are important for intestinal homeostasis as they kill microbes and yet produce regulatory cytokines. Activity of the NLRP3 (nucleotide-binding leucine-rich repeat-containing pyrin receptor 3) inflammasome, a major sensor of stress and microorganisms that results in pro-inflammatory cytokine production and cell death, must be tightly controlled in the intestine. We demonstrate that resident cMPs are hyporesponsive to NLRP3 inflammasome activation owing to a remarkable level of posttranscriptional control of NLRP3 and pro-interleukin-1β (proIL-1β) protein expression, which was also seen for tumor necrosis factor-α and IL-6, but lost during experimental colitis. Resident cMPs rapidly degraded NLRP3 and proIL-1β proteins by the ubiquitin/proteasome system. Finally, blocking IL-10R-signaling in vivo enhanced NLRP3 and proIL-1β protein but not mRNA levels in resident cMPs, implicating a role for IL-10 in environmental conditioning of cMPs. These data are the first to show dramatic posttranscriptional control of inflammatory cytokine production by a relevant tissue-derived macrophage population and proteasomal degradation of proIL-1β and NLRP3 as a mechanism to control inflammasome activation, findings which have broad implications for our understanding of intestinal and systemic inflammatory diseases.
Insights
Resident colonic macrophages maintain gut health by limiting NLRP3 inflammasome activation through protein degradation. This control is lost in colitis, impacting inflammatory diseases.
Area of Science:
- Immunology
- Gastroenterology
- Cell Biology
Background:
- Colonic macrophages (cMPs) are crucial for intestinal homeostasis, balancing microbial defense and immune regulation.
- The NLRP3 inflammasome (nucleotide-binding leucine-rich repeat-containing pyrin receptor 3) is a key inflammatory pathway that must be tightly regulated in the gut.
Purpose of the Study:
- To investigate the mechanisms controlling NLRP3 inflammasome activation in resident colonic macrophages.
- To understand how this regulation differs during inflammatory conditions like colitis.
Main Methods:
- Analysis of NLRP3 inflammasome components (NLRP3, pro-interleukin-1β) and cytokine expression (TNF-α, IL-6) in colonic macrophages.
- Investigation of protein degradation pathways, specifically the ubiquitin/proteasome system.
- In vivo experiments blocking IL-10 receptor (IL-10R) signaling.
Main Results:
- Resident cMPs exhibit hyporesponsiveness to NLRP3 inflammasome activation due to posttranscriptional control of NLRP3 and pro-interleukin-1β (proIL-1β) protein levels.
- This posttranscriptional regulation, including rapid protein degradation via the ubiquitin/proteasome system, is impaired during experimental colitis.
- Blocking IL-10R signaling increased NLRP3 and proIL-1β protein, but not mRNA, in resident cMPs, suggesting IL-10's role in their environmental conditioning.
Conclusions:
- Colonic macrophages employ significant posttranscriptional mechanisms, including proteasomal degradation, to control inflammasome activation and cytokine production.
- Dysregulation of these mechanisms during colitis contributes to intestinal inflammation.
- These findings provide novel insights into the regulation of innate immunity in the gut and have implications for inflammatory diseases.
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