To explore the role of lipoxin A4 (LXA4) on inflammasome and inflammatory activity in macrophages activated by Porphyromonas gingivalis lipopolysaccharide (PgLPS) one of the major causative agents of chronic periodontitis. The mouse macrophage cell line RAW264.7 was used to produce an activated inflammation model. Markers of inflammasome and inflammatory activity and autophagy were assessed by ELISA, reverse transcription polymerase chain reaction (RT-PCR), and Western blot assay. Markers of inflammasome activity, inflammation and autophagy increased with Pg LPS concentration. They also increased with increasing exposure to Pg LPS up to 12h but decreased at 24h. However, markers of autophagy increased. Phosphorylated NF-κBp65 decreased with LXA4, which was similar to results obtained with the autophagy inducer, rapamycin. LXA4 promoted autophagy and inhibited activation of inflammasomes and inflammation markers in macrophage inflammation induced by PgLPS and this action was linked to the phosphorylation of NF-κB.

Background: Macrophages are known to play a crucial role in the chronic inflammation associated with Chronic Obstructive Pulmonary Disease (COPD). BML-111, acting as a lipoxin A4 (LXA4) receptor agonist, has shown to be effective in protecting against COPD. However, the precise mechanism by which BML-111 exerts its protective effect remains unclear.Methods: In order to establish a cell model of inflammation, cigarette smoke extract (CSE) was used on the RAW264.7 cell line. Afterwards, an Enzyme-linked immunosorbent assay (ELISA) kit was employed to measure concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1 beta), interleukin-18 (IL-18), and interleukin-10 (IL-10) in the cell supernatants of the RAW264.7 cells. In this study, we examined the markers of macrophage polarization using two methods: quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis. Additionally, we detected the expression of Notch-1 and Hes-1 through Western blotting.Results: BML-111 effectively suppressed the expression of pro-inflammatory cytokines TNF-alpha, IL-1 beta, and IL-18, as well as inflammasome factors NLRP3 and Caspase-1, while simultaneously up-regulating the expression of the anti-inflammatory cytokine IL-10 induced by CSE. Moreover, BML-111 reduced the expression of iNOS, which is associated with M1 macrophage polarization, and increased the expression of Arg-1, which is associated with M2 phenotype. Additionally, BML-111 downregulated the expression of Hes-1 and the ratio of activated Notch-1 to Notch-1 induced by CSE. The effect of BML-111 on inflammation and macrophage polarization was reversed upon administration of the Notch-1 signaling pathway agonist Jagged1.Conclusion: BML-111 has the potential to suppress inflammation and modulate M1/M2 macrophage polarization in RAW264.7 cells. The underlying mechanism may involve the Notch-1 signaling pathway.

This study investigates the mechanism by which lipoxin A4 (LXA4) attenuates myocardial ischemia/reperfusion injury (MIRI). Using a rat MIRI model, we evaluated coronary flow, histopathology, cardiac enzymes (cTnI/CK-MB), oxidative stress markers (superoxide dismutase, SOD; malondialdehyde, MDA; glutathione peroxidase, GSH-Px), and protein expression (neurogenic locus notch homolog protein 1 [Notch1], hairy and enhancer of split 1 [Hes1], nuclear factor-erythroid 2-related factor 2 [Nrf2], β-tubulin). Pharmacological inhibitors N -[ N -(3,5-difluorophenacetyl)-l-alanyl]- S -phenylglycinet-butylester (DAPT; Notch1) and ML385 (Nrf2) were co-administered with LXA4. Results demonstrated that I/R injury significantly increased microtubule disruption (48.5 ± 6.7% vs control 4.8 ± 0.9%; p < 0.01), decreased SOD (42.1 ± 5.3 vs 89.6 ± 8.7 U/mg), and GSH-Px (15.2 ± 2.1 vs 34.8 ± 4.5 U/mg), and elevated MDA (6.9 ± 0.8 vs 2.1 ± 0.3 nmol/mg; p < 0.05). Notch1, Hes1, and nuclear Nrf2 decreased by 58, 63, and 52%, respectively. LXA4 treatment reversed these effects (23.6 ± 3.6% microtubule disruption; p < 0.05), with DAPT or ML385 abolishing LXA4’s protection. These findings indicate that LXA4 protects against MIRI by preserving microtubule integrity and activating the Notch1/Hes1/Nrf2 pathway, revealing a novel mechanism for oxidative stress suppression in cardiomyocytes.