Inhibiting NF-κB Signaling Activation Reduces Retinal Neovascularization by Promoting a Polarization Shift in
Ailing Sui1, Xiuping Chen1, Anna M Demetriades1
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Purpose:
Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling is involved in regulating tumor angiogenesis and metastasis; however, the exact mechanism of action in retinal neovascularization (RNV) remains unclear. The purpose of this study was to determine the role and underlying mechanism of NF-κB in regulating RNV in retinal neovascularization mice.
Methods:
Expression levels of NF-κB signaling were detected by immunofluorescence staining and western blotting in retinas of oxygen-induced retinopathy (OIR) mice. OIR mice were treated with either pyrrolidinedithiocarbamate (PDTC), a NF-κB signaling inhibitor, or PBS, and retinal flat-mounts were performed to quantify the area of RNV and the recruitment of retinal macrophages by immunofluorescence staining. Macrophage polarization detected by flow cytometric analysis and the expression of macrophage polarization-associated genes were evaluated by immunofluorescence staining, quantitative RT-PCR, and western blotting.
Results:
Expression levels of phosphorylated IκBα (p-IκBα) and p-p65 increased in OIR mice. Inhibiting NF-κB signaling activation by PDTC significantly reduced RNV. After treatment with PDTC, a reduction in the quantity of macrophages was observed: M1 polarized macrophages decreased, and M2 polarized macrophages increased; the expression of M1 macrophage-associated cytokines decreased and M2 macrophage-associated cytokines increased in the retinas of OIR mice.
Conclusions:
Blocking activation of NF-κB signaling reduces RNV by promoting polarization of M1 macrophages to M2 macrophages in OIR mice.
Insights
Blocking Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling reduces retinal neovascularization (RNV) in mice. This occurs by shifting macrophage polarization from M1 to M2, decreasing inflammation and promoting healing.
Area of Science:
- Ophthalmology
- Immunology
- Molecular Biology
Background:
- Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling influences tumor angiogenesis and metastasis.
- The precise role of NF-κB in retinal neovascularization (RNV) is not fully understood.
Purpose of the Study:
- To investigate the role and mechanism of NF-κB in regulating RNV.
- To determine how NF-κB affects macrophage polarization in the context of RNV.
Main Methods:
- Utilized oxygen-induced retinopathy (OIR) mouse models.
- Assessed NF-κB signaling activation via immunofluorescence and western blotting.
- Quantified RNV and macrophage recruitment using retinal flat-mounts.
- Analyzed macrophage polarization and gene expression through flow cytometry, immunofluorescence, and RT-PCR.
Main Results:
- NF-κB signaling components (p-IκBα, p-p65) were upregulated in OIR mice.
- Inhibition of NF-κB with PDTC significantly decreased RNV.
- PDTC treatment led to decreased M1 macrophages and increased M2 macrophages, with corresponding changes in cytokine expression.
Conclusions:
- Inhibition of NF-κB signaling effectively reduces RNV in OIR mice.
- NF-κB blockade promotes the M1 to M2 macrophage polarization shift.
- This shift in macrophage polarization is a key mechanism by which NF-κB inhibition impacts RNV.
