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4-Hydroxynonenal inhibits interleukin-1 beta converting enzyme
D W Davis1, R F Hamilton, A Holian
1Department of Internal Medicine, University of Texas Houston Health Science 77030, USA.
Summary
4-hydroxynonenal (HNE), a product of lipid peroxidation, inhibits the release of interleukin-1 beta (IL-1 beta) from human mononuclear cells. This suppression of IL-1 beta release is likely due to HNE directly inhibiting the ICE enzyme activity.
Area of Science:
- Biochemistry
- Immunology
- Cell Biology
Background:
- Lipid peroxidation generates reactive metabolites like 4-hydroxynonenal (HNE) during oxidative stress.
- These metabolites play roles in disease pathogenesis and cellular processes.
- HNE is known to be thiol-reactive and exert various cellular effects.
Purpose of the Study:
- To investigate the inhibitory effect of HNE on the cysteine protease, interleukin-1 beta (IL-1 beta) converting enzyme (ICE).
- To determine if HNE affects the release of cytokines from human blood mononuclear cells stimulated by lipopolysaccharide (LPS).
Main Methods:
- Assessing the dose-dependent inhibition of IL-1 beta, IL-10, and TNF-alpha release from LPS-stimulated human blood mononuclear cells by HNE.
- Measuring intracellular pro-IL-1 beta levels following HNE treatment.
- Evaluating ICE activity in lysed cells and with purified recombinant human ICE (rHu-ICE) using fluorogenic substrates and recombinant pro-IL-1 beta.
Main Results:
- HNE dose-dependently inhibited the release of IL-1 beta (EC50 5 microM) and IL-10 (EC50 2 microM), and to a lesser extent TNF-alpha (EC50 15 microM).
- HNE did not affect LPS-stimulated intracellular pro-IL-1 beta levels.
- HNE directly inhibited ICE activity in lysed cells and purified rHu-ICE in a dose-dependent manner.
Conclusions:
- HNE suppresses mononuclear cell release of IL-1 beta, likely by direct interaction with the active site cysteine of ICE.
- These findings suggest HNE's role in modulating mononuclear cell function under oxidative stress conditions.