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Degradation of interleukin 1beta by matrix metalloproteinases
1Department of Biochemistry, Tokyo College of Pharmacy, Horinouchi, Hachioji, Tokyo 192-03, Japan.
Abstract:
Matrix metalloproteinases (MMPs) and interleukin 1 (IL-1) are implicated in inflammation and tissue destruction, where IL-1 is a potent stimulator of connective tissue cells to produce the extracellular matrix-degrading MMPs. Here, we report that IL-1beta, but not IL-1alpha, is degraded by MMP-1 (interstitial collagenase), MMP-2 (gelatinase A), MMP-3 (stromelysin 1), and MMP-9 (gelatinase B). This degradation was effectively blocked by tissue inhibitor of metalloproteinases (TIMP)-1. When IL-1beta was treated with MMPs it lost the ability to enhance the synthesis of prostaglandin E2 and pro-MMP-3 in human fibroblasts. The primary cleavage site of IL-1beta by MMP-2 was identified at the Glu25-Leu26 bond. These results suggest that IL-1beta stimulates connective tissue cells to produce MMPs, but activated MMPs in turn negatively regulate the activity of IL-1beta.
Insights
Matrix metalloproteinases (MMPs) degrade interleukin-1 beta (IL-1beta), reducing its inflammatory activity. This MMP-mediated degradation of IL-1beta offers a novel regulatory mechanism in tissue homeostasis and inflammation.
Area of Science:
- Biochemistry
- Cell Biology
- Immunology
Background:
- Matrix metalloproteinases (MMPs) and interleukin-1 (IL-1) play key roles in inflammation and tissue destruction.
- IL-1 is a known stimulator of connective tissue cells, prompting the production of MMPs that degrade the extracellular matrix.
Purpose of the Study:
- To investigate the interaction between IL-1beta and MMPs.
- To determine if MMPs can degrade IL-1beta and affect its biological activity.
Main Methods:
- Incubation of IL-1beta with various MMPs (MMP-1, MMP-2, MMP-3, MMP-9).
- Assessment of IL-1beta degradation and its functional consequences on prostaglandin E2 and pro-MMP-3 synthesis in human fibroblasts.
- Identification of the IL-1beta cleavage site by MMP-2 using biochemical methods.
- Inhibition studies using tissue inhibitor of metalloproteinases (TIMP)-1.
Main Results:
- IL-1beta, but not IL-1alpha, was degraded by MMP-1, MMP-2, MMP-3, and MMP-9.
- Degradation of IL-1beta by MMPs was blocked by TIMP-1.
- MMP-treated IL-1beta lost its ability to enhance prostaglandin E2 and pro-MMP-3 synthesis in human fibroblasts.
- The primary cleavage site of IL-1beta by MMP-2 was identified at the Glu25-Leu26 bond.
Conclusions:
- MMPs can directly degrade IL-1beta, suggesting a negative feedback loop where MMPs regulate IL-1beta activity.
- This degradation by MMPs leads to a loss of IL-1beta's pro-inflammatory and matrix-degrading stimulating functions.
- The findings reveal a novel mechanism of biological regulation involving MMPs and IL-1beta in inflammatory processes and tissue remodeling.