Purpose: To determine the effects of dietary omega-3 polyunsaturated fatty acids (PUFAs) on recruitment of natural killer (NK) cells and resolution responses in antigen-induced peritonitis in mice.... Show morePurpose: To determine the effects of dietary omega-3 polyunsaturated fatty acids (PUFAs) on recruitment of natural killer (NK) cells and resolution responses in antigen-induced peritonitis in mice. Methods: Mice were fed fish oil-enriched or control diets, immunized twice and challenged intraperitoneally with methylated bovine serum albumin. Prior to and at different time-points following inflammation induction, expression of surface molecules on peritoneal cells was determined by flow cytometry, concentration of soluble mediators in peritoneal fluid by ELISA or Luminex, and of lipid mediators by LC-MS/MS, and number of apoptotic cells in mesenteric lymph nodes by TUNEL staining. Results: Mice fed the fish oil diet had higher number of CD11b(+)CD27(-) NK cells as well as a higher proportion of CD107a(+) NK cells in their peritoneum 6 h after inflammation induction than mice fed the control diet. They also had higher numbers of CCR5(+) NK cells and higher concentrations of CCL5 and CXCL12. Additionally, a higher fraction of apoptotic neutrophils but lower fraction of CD47(+) neutrophils were present in the peritoneum of mice fed the fish oil diet 6 h after inflammation induction and the fish oil fed mice had a shorter resolution interval. They also had lower concentrations of pro-inflammatory mediators but higher concentrations of the anti-inflammatory/pro-resolution mediators TGF-beta, IGF-1, and soluble TNF RII, as well as higher ratios of hydroxyeicosapentaenoic acid (HEPE) to hydroxyeicosatetraenoic acid (HETE) than mice fed the control diet. Conclusion: The results demonstrate that dietary fish oil increases the number of mature NK cells at the inflamed site in antigen-induced peritonitis and enhances several key hallmarks of resolution of inflammation, casting light on the potential mechanisms involved. Show less
Brouwers, H.; Jonasdottir, H.S.; Kuipers, M.E.; Kwekkeboom, J.C.; Auger, J.L.; Gonzalez-Torres, M.; ... ; Ioan-Facsinay, A. 2020
Polyunsaturated fatty acids (PUFAs) and their metabolites are potent regulators of inflammation. Generally, omega (n)-3 PUFAs are considered proresolving whereas n-6 PUFAs are classified as... Show morePolyunsaturated fatty acids (PUFAs) and their metabolites are potent regulators of inflammation. Generally, omega (n)-3 PUFAs are considered proresolving whereas n-6 PUFAs are classified as proinflammatory. In this study, we characterized the inflammatory response in murine peritonitis and unexpectedly found the accumulation of adrenic acid (AdA), a poorly studied n-6 PUFA. Functional studies revealed that AdA potently inhibited the formation of the chemoattractant leukotriene B-4 (LTB4), specifically in human neutrophils, and this correlated with a reduction of its precursor arachidonic acid (AA) in free form. AdA exposure in human monocyte-derived macrophages enhanced efferocytosis of apoptotic human neutrophils. In vivo, AdA treatment significantly alleviated arthritis in an LTB4-dependent murine arthritis model. Our findings are, to our knowledge, the first to indicate that the n-6 fatty acid AdA effectively blocks production of LTB4 by neutrophils and could play a role in resolution of inflammation in vivo. Show less
Murine zymosan-induced peritonitis is a widely used model for studying the molecular and cellular events responsible for the initiation, persistence and/or resolution of inflammation. Among these... Show moreMurine zymosan-induced peritonitis is a widely used model for studying the molecular and cellular events responsible for the initiation, persistence and/or resolution of inflammation. Among these events, it is becoming increasingly evident that changes in glycosylation of proteins, especially in the plasma and at the site of inflammation, play an important role in the inflammatory response. Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS)-based glycosylation profiling, we investigated the qualitative and quantitative effect of zymosan-induced peritonitis on N-glycosylation in mouse plasma and peritoneal fluid. Our results show that both N-glycomes exhibit highly similar glycosylation patterns, consisting mainly of diantennary and triantennary complex type N-glycans with high levels (> 95 %) of galactosylation and sialylation (mostly NeuGc) and a medium degree of core fucosylation (30 %). Moreover, MS/MS structural analysis, assisted by linkage-specific derivatization of sialic acids, revealed the presence of O-acetylated sialic acids as well as disialylated antennae ("branching sialylation") characterized by the presence of alpha 2-6-linked NeuGc on the GlcNAc of the NeuGc alpha 2-3-Gal beta 1-3-GlcNAc terminal motif. A significant decrease of (core) fucosylation together with an increase of both alpha 2-3-linked NeuGc and "branching sialylation" were observed in N-glycomes of mice challenged with zymosan, but not in control mice injected with PBS. Importantly, substantial changes in glycosylation were already observed 12 h after induction of peritonitis, thereby demonstrating an unexpected velocity of the biological mechanisms involved. Show less
Anuforo, O.; Bjarnarson, S.; Jonasdottir, H.; Giera, M.; Hardardottir, I.; Freysdottir, J. 2016
