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Effects of proteinase inhibitors on polymorphonuclear neutrophil polarization
K Aoshiba1, A Nagai, T Takizawa
1First Department of Medicine, Tokyo Women's Medical College, Japan.
Abstract:
Polarization of polymorphonuclear neutrophils (PMNs) can be elicited by the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP) and the microtubule-disrupting compound colchicine. Here we report on whether natural and synthetic proteinase inhibitors alter the polarizing response to these two agents. The alpha 1-proteinase inhibitor, N-tosyl-L-phenylalanine chloromethyl ketone, and N alpha-tosyl-L-lysine chloromethyl ketone suppress fMLP-induced polarization and locomotion in a dose-dependent fashion, but none of them affects colchicine-induced polarization. We suggest that proteinase inhibitors suppress fMLP-induced polarization by blocking cell surface proteinases that generate an intracellular signal for cytoskeletal change and polarization.
Insights
Natural and synthetic proteinase inhibitors block polymorphonuclear neutrophil (PMN) polarization induced by fMLP, but not colchicine. This suggests proteinase inhibitors interfere with cell surface proteinases crucial for fMLP signaling.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Polymorphonuclear neutrophils (PMNs) are key immune cells involved in inflammation.
- PMN polarization is a critical process for cell migration and function.
- Chemotactic peptides like fMLP and compounds like colchicine are known to induce PMN polarization.
Purpose of the Study:
- To investigate the effect of natural and synthetic proteinase inhibitors on PMN polarization.
- To determine if proteinase inhibitors differentially affect polarization induced by fMLP versus colchicine.
- To elucidate the mechanism by which proteinase inhibitors might modulate PMN polarization.
Main Methods:
- Assessing PMN polarization in response to fMLP and colchicine.
- Evaluating the impact of alpha 1-proteinase inhibitor, N-tosyl-L-phenylalanine chloromethyl ketone, and N alpha-tosyl-L-lysine chloromethyl ketone on PMN polarization.
- Dose-response analysis of inhibitor effects.
Main Results:
- Alpha 1-proteinase inhibitor, N-tosyl-L-phenylalanine chloromethyl ketone, and N alpha-tosyl-L-lysine chloromethyl ketone significantly suppressed fMLP-induced PMN polarization and locomotion in a dose-dependent manner.
- These proteinase inhibitors did not affect colchicine-induced PMN polarization.
- The observed suppression was specific to fMLP-induced responses.
Conclusions:
- Proteinase inhibitors interfere with the signaling pathway initiated by fMLP, leading to reduced PMN polarization.
- The mechanism likely involves the inhibition of cell surface proteinases essential for generating intracellular signals for cytoskeletal rearrangement.
- These findings highlight a potential role for proteinases in regulating fMLP-mediated neutrophil responses.