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Activation and Measurement of NLRP3 Inflammasome Activity Using IL-1β in Human Monocyte-derived Dendritic Cells
Published on: May 22, 2014
Pyrin levels in human monocytes and monocyte-derived macrophages regulate IL-1beta processing and release
Sudarshan Seshadri1, Michelle D Duncan, Judith M Hart
1Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH 43210, USA.
Journal of Immunology (Baltimore, Md. : 1950)
|July 10, 2007
Summary
Pyrin levels decrease as monocytes mature into macrophages, impairing interleukin-1beta (IL-1beta) release. Restoring pyrin enhances IL-1beta processing and release in these immune cells.
Area of Science:
- Immunology
- Cell Biology
- Molecular Medicine
Background:
- Monocytes and macrophages are crucial for innate immunity, producing caspase-1 for pro-interleukin-1beta (pro-IL-1beta) processing.
- Macrophages exhibit limited IL-1beta release compared to monocytes, suggesting regulatory mechanisms.
- Mutations in the pyrin gene (MEFV) are linked to familial Mediterranean fever, implicating pyrin in IL-1beta regulation.
Purpose of the Study:
- To investigate if differential pyrin expression explains the varying IL-1beta processing and release between monocytes and macrophages.
- To determine the role of pyrin in modulating IL-1beta processing and release.
Main Methods:
- Studied pyrin mRNA and protein expression in human monocytes and monocyte-derived macrophages.
- Utilized HEK293 cells for transfection experiments with pyrin, caspase-1, ASC, and IL-1beta.
- Employed pyrin small interference RNA (siRNA) to assess pyrin's effect on pro-IL-1beta processing in THP-1 cells and monocytes.
Main Results:
- Monocyte-derived macrophages express significantly lower levels of pyrin mRNA and protein compared to monocytes.
- Pyrin expression levels directly correlated with IL-1beta processing in both cell types.
- Ectopic pyrin expression in HEK293 cells dose-dependently induced IL-1beta processing and release; pyrin siRNA suppressed this process.
Conclusions:
- Monocyte to macrophage maturation leads to diminished pyrin expression and consequently reduced IL-1beta processing and release.
- Pyrin plays a critical role in augmenting IL-1beta processing and release, particularly upon endotoxin-induced activation of mononuclear phagocytes.
- Pyrin's function in regulating IL-1beta release offers potential therapeutic insights for inflammatory conditions.
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