Resolution of PMA-induced skin inflammation involves interaction of IFN-γ and ALOX15
Guojun Zhang1, Xiaoman Liu, Chunhui Wang
1Research Center for Immunology, Xinxiang Medical University, Xinxiang, Henan 453003, China.
Background:
Acute inflammation and its timely resolution play important roles in the body's responses to the environmental stimulation. Although IFN-γ is well known for the induction of inflammation, its role in the inflammation resolution is still poorly understood.
Methodology And Principal Findings:
In this study, we investigated the function of interferon gamma (IFN-γ) during the resolution of PMA-induced skin inflammation in vivo. The results revealed that the expression levels of IL-6, TNF-α, and monocyte chemoattractant protein 1 (MCP-1) in skin decreased during the resolution stage of PMA-induced inflammation, while IFN-γ is still maintained at a relatively high level. Neutralization of endogenous IFN-γ led to accelerated reduction of epidermal thickness and decreased epithelial cell proliferation. Similarly, decreased infiltration of inflammatory cells (Gr1(+) or CD11b(+) cells) and a significant reduction of proinflammatory cytokines were also observed upon the blockade of IFN-γ. Furthermore, neutralization of IFN-γ boosted ALOX15 expression of the skin during inflammation resolution. In accordance, application of lipoxin A4 (LXA4, a product of ALOX15) obtained a proresolution effect similar to neutralization of IFN-γ. These results demonstrated that through upregulating ALOX15-LXA4 pathway, blockage of IFN-γ can promote the resolution of PMA-induced skin inflammation.
Insights
Blocking interferon gamma (IFN-γ) promotes skin inflammation resolution by upregulating the ALOX15-lipoxin A4 pathway. This finding offers new insights into managing inflammatory conditions.
Area of Science:
- Immunology
- Dermatology
- Molecular Biology
Background:
- Acute inflammation and its resolution are critical for tissue homeostasis.
- Interferon gamma (IFN-γ) is known to induce inflammation, but its role in resolution is unclear.
Purpose of the Study:
- To investigate the role of IFN-γ in resolving skin inflammation.
- To elucidate the mechanisms by which IFN-γ influences inflammation resolution.
Main Methods:
- Studied PMA-induced skin inflammation in vivo.
- Neutralized endogenous IFN-γ using antibodies.
- Measured inflammatory markers, cell proliferation, and cytokine levels.
- Assessed the expression of ALOX15 and lipoxin A4 (LXA4).
Main Results:
- IFN-γ remained high during inflammation resolution.
- IFN-γ neutralization accelerated epidermal thinning and reduced cell proliferation.
- Blocking IFN-γ decreased inflammatory cell infiltration and pro-inflammatory cytokines.
- IFN-γ blockade upregulated ALOX15 expression and promoted LXA4 production.
Conclusions:
- IFN-γ blockade promotes the resolution of PMA-induced skin inflammation.
- The pro-resolution effect is mediated by the upregulation of the ALOX15-LXA4 pathway.
- Targeting IFN-γ may be a therapeutic strategy for inflammatory skin diseases.
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