AUTHOR=Stevenson Emily R. , O’Brien James P. , Manuel Allison M. , Uvalle Crystal E. , Buchan Gregory J. , Mullett Steven J. , Lockwood Karina , Suber Tomeka , Freeman Bruce A. , Gelhaus Stacy L. 

TITLE=Nitroalkene inhibition of pro-inflammatory macrophage effector function via modulation of signaling metabolite levels

JOURNAL=Frontiers in Physiology

VOLUME=Volume 16 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2025.1426102

DOI=10.3389/fphys.2025.1426102

ISSN=1664-042X

ABSTRACT=IntroductionClassically activated innate immune cells undergo a metabolic switch to aerobic glycolysis to support effector function. We report that the small-molecule nitroalkene 10-n-octadec-9-enoic acid (NO2-OA) attenuates the Warburg- like phenotype of aerobic glycolysis in lipopolysaccharide (LPS)-activated macrophages, thus inhibiting pro-inflammatory signaling.MethodsRAW264.7 and bone marrow derived macrophage were treated with LPS with and without NO2-OA or 1400W. Pro-inflammatory cytokines were measured by ELISA and protein expression was determined by immunoblot. Central carbon metabolites with and without 13C stable isotope tracing were measured using liquid chromatography-high resolution mass spectrometry.ResultsOverall, the present observations indicate that nitroalkene-induced changes in central carbon metabolism contribute to the anti-inflammatory actions of this class of multi-target lipid signaling mediators. Comparison of macrophage responses to NO2-OA with the inducible nitric oxide synthase (NOS2 and iNOS) inhibitor 1400W affirms that NO2-OA inhibition of NOS2 expression and activity alone was not sufficient to account for the decreases in pro-inflammatory cytokine expression. NO2-OA treatment reduced intracellular succinate levels, which may be attributed to a concomitant reduction in intracellular itaconate and reliance on glutamine, thereby contributing to hypoxia-inducible factor 1α (HIF1α) destabilization observed in LPS-activated macrophages.ConclusionThe current data provide additional perspective on the actions of this small-molecule electrophile, which is currently in a Phase 2 clinical trial for the treatment of obesity-related chronic pulmonary inflammation and associated airway dysfunction.