MMP-12 polarizes neutrophil signalome towards an apoptotic signature
Upendra Chalise1, Mediha Becirovic-Agic1, Shelby R Konfrst1
1Department of Cellular and Integrative Physiology, Center for Heart and Vascular Research, University of Nebraska Medical Center, Omaha, NE 68198, United States of America; Research Service, Nebraska-Western Iowa Health Care System, Omaha, NE 68105, United States of America.
Abstract:
While macrophages are well-known to polarize across the inflammatory spectrum, neutrophils have only recently been found to activate in a similar fashion in response to pro- or anti-inflammatory stimuli. Matrix metalloproteinase (MMP)-12 mediates neutrophil physiology with direct signaling mechanisms yet to be investigated. We hypothesized MMP-12 may modify neutrophil signaling. Bone marrow neutrophils were stimulated with interleukin (IL-1β; pro-inflammatory), IL-4 (anti-inflammatory), or MMP-12. The secretome was mapped by multi-analyte profiling and intracellular signaling evaluated by array. IL-1β induced a cytokine-mediated inflammatory LPS-like signalome, with upregulation of pro-inflammatory cytokines such as interferon gamma (IFNγ,15.2-fold,p = 0.001), chemokine (C-X-C motif) ligand 1 (CXCL1,8.4-fold,p = 0.005), and tumor necrosis factor alpha (TNFα,11.2-fold,p = 0.004). IL-4 induced strong intracellular signaling with upregulation of mitogen-activated protein kinase kinase (MEK1;1.9-fold,p = 0.0005) and downregulation of signal transducer and activator of transcription 4 (STAT4;0.77-fold,0.001). MMP-12 increased IL-4 secretion 20-fold and induced a robust apoptotic neutrophil signalome with upregulation of forkhead box O1 (FOXO1;1.4-fold,p < 0.0001) and downregulation of WNT signaling with MMP-12 cleavage of the adherens junction components β-catenin, cahderin-3, and catenin-α2. In conclusion, neutrophils shifted phenotype by stimuli, with MMP-12 inducing a unique apoptotic signalome with higher resemblance to the anti-inflammatory signalome. SIGNIFICANCE: This study revealed that neutrophils demonstrate unique polarization signaling responses to specific stimuli, with the matrix metalloproteinase (MMP)-12 signalome showing similarity to the IL-4 signalome. MMP-12 polarized neutrophils towards a strong apoptotic signature by upregulating FOXO1 and downregulating WNT signaling. Our results highlight that neutrophils display more plasticity than previously appreciated.
Insights
Neutrophils exhibit adaptable signaling in response to stimuli. Matrix metalloproteinase (MMP)-12 induces an apoptotic neutrophil signal, similar to anti-inflammatory interleukin (IL)-4 signaling.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Macrophages are known for inflammatory polarization, but neutrophil activation plasticity is a recent discovery.
- Matrix metalloproteinase (MMP)-12's role in neutrophil signaling requires further investigation.
Purpose of the Study:
- To investigate the hypothesis that MMP-12 modifies neutrophil signaling pathways.
- To compare neutrophil responses to pro-inflammatory (IL-1β), anti-inflammatory (IL-4), and MMP-12 stimuli.
Main Methods:
- Bone marrow neutrophils were stimulated with IL-1β, IL-4, or MMP-12.
- Secretome analysis was performed using multi-analyte profiling.
- Intracellular signaling was evaluated using antibody arrays.
Main Results:
- IL-1β induced an inflammatory signalome with upregulated cytokines like IFNγ, CXCL1, and TNFα.
- IL-4 triggered intracellular signaling, upregulating MEK1 and downregulating STAT4.
- MMP-12 increased IL-4 secretion, induced apoptosis, upregulated FOXO1, and downregulated WNT signaling by cleaving β-catenin, cadherin-3, and catenin-α2.
Conclusions:
- Neutrophils demonstrate stimulus-dependent phenotype shifts.
- MMP-12 induces a distinct apoptotic neutrophil signalome, resembling the anti-inflammatory IL-4 response.
- Neutrophils possess greater plasticity than previously understood.
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