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Chronic inflammation is a hallmark of atherosclerosis and results from an imbalance between proinflammatory and proresolving signaling. The human GPR32 receptor, together with the ALX/FPR2 receptor, transduces biological actions of several proresolving mediators that stimulate resolution of inflammation. However, since no murine homologs of the human GPR32 receptor exist, comprehensive in vivo studies are lacking. Using human atherosclerotic lesions from carotid endarterectomies and creating a transgenic mouse model expressing human GPR32 on a Fpr2xApoE doubleKO background ([hGPR32.sub.myc] * [Fpr.sup.2-/-] * [Apoe.sup.-/-]), we investigated the role of GPR32 in atherosclerosis and self-limiting acute inflammation. GPR32 mRNA was reduced in human atherosclerotic lesions and correlated with the immune cell markers ARG1, NOS2, and FOXP3. Atherosclerotic lesions, necrotic core, and aortic inflammation were reduced in [hGPR32.sub.myc]Tg * [Fpr2.sup.-/-] * [Apoe.sup.-/-] transgenic mice as compared with [Fpr2.sup.-/-] * [Apoe.sup.-/-] nontransgenic littermates. In a zymosan-induced peritonitis model, the [hGPR32.sub.myc]Tg * [Fpr2.sub.-/-] * [Apoe.sub.-/-] transgenic mice had reduced inflammation at 4 hours and enhanced proresolving macrophage responses at 24 hours compared with nontransgenic littermates. The GPR32 agonist aspirin-triggered resolvin D1 (AT-RvD1) regulated leukocyte responses, including enhancing macrophage phagocytosis and intracellular signaling in [hGPR32.sub.myc]Tg * [Fpr2.sup.-/-] * [Apoe.sup.-/-] transgenic mice, but not in [Fpr2.sup.-/-] * [Apoe.sup.-/-] nontransgenic littermates. Together, these results provide evidence that GPR32 regulates resolution of inflammation and is atheroprotective in vivo., Introduction Resolution of acute inflammation is an active, coordinated response aimed at terminating the inflammatory response and restoring tissue homeostasis (1). Resolution of inflammation is regulated by a superfamily of [...]

Background and Purpose: Atherosclerosis is characterized by a chronic non-resolving inflammation in the arterial wall. Aspirin-triggered lipoxin A4 (ATL) is a potent anti-inflammatory mediator, involved in the resolution of inflammation. However, the therapeutic potential of immune targeting by means of ATL in atherosclerosis has not previously been explored. The aim of the present study was to determine the effects of ATL and its receptor Fpr2 on atherosclerosis development and progression in apolipoprotein E deficient (ApoE-/- ) mice.Experimental Approach: ApoE-/-  × Fpr2+/+ and ApoE-/-  × Fpr2-/- mice were generated. Four-week-old mice fed a high-fat diet for 4 weeks and 16-week-old mice fed chow diet received osmotic pumps containing either vehicle or ATL for 4 weeks. Atherosclerotic lesion size and cellular composition were measured in the aortic root and thoracic aorta. Lipid levels and leukocyte counts were measured in blood and mRNA was isolated from abdominal aorta and spleen.Key Results: ATL blocked atherosclerosis progression in the aortic root and thoracic aorta of ApoE-/- mice. In addition, ATL reduced macrophage infiltration and apoptotic cells in atherosclerotic lesions. The mRNA levels of several cytokines and chemokines in the spleen and aorta were reduced by ATL, whereas circulating leukocyte levels were unchanged. The ATL-induced athero-protection was absent in ApoE-/- mice lacking the Fpr2 receptor.Conclusion and Implications: ATL blocked atherosclerosis progression by means of an Fpr2-mediated reduced local and systemic inflammation. These results suggest this anti-inflammatory and pro-resolving agent has therapeutic potential for the treatment of atherosclerosis.Linked Articles: This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc. [ABSTRACT FROM AUTHOR]

Background: The immune cell response in atherosclerotic plaques is characterized by an impaired resolution of inflammation (1). Resolvin E1 (RvE1), a specialized pro-resolving lipid mediator derived from omega-3 polyunsaturated fatty acids (PUFA) has been shown to play a critical role in atherosclerosis by promoting the resolution of the inflammation (2). The aim of the present study was to unravel the role of omega-3 PUFA, RvE1 and the RvE1 receptor ChemR23 in the process of atherosclerotic plaque calcification. Methods: Fat-1 transgene (Fat-1tg), which enables the endogenous production of n-3 PUFA, was inserted in apolipoprotein E (ApoE)-deficient mice, in combination or not with genetic deletion of ChemR23. Calcification was assessed by Alizarin Red staining and macrophage markers were assessed by immunohistochemistry in aortic root sections. Results: Our results show that 72 week old Fat-1tg × Apoe-/- mice developed less atherosclerotic plaque calcification compared with Apoe-/- mice (0-3% vs 4-8%, p < 0.001). Moreover, deletion of ChemR23 enhanced atherosclerotic plaque calcification (4-13% vs. 4-8%, p < 0.001), and this effect was not reversed by the presence of Fat-1tg (4-14% vs. 4-8%, p < 0.001). Furthermore, the Fat- 1tg × Apoe-/- mice had significantly higher expression of the M2 macrophage marker Arg1 compared with Apoe-/- mice (17.4 ± 2.5% vs 5.1 ± 1.5%; p < 0.0001), which was reversed by genetic deletion of ChemR23 (5.0 ± 1.1% vs. 17.4 ± 2.5%; p < 0.0001 vs Fat-1tg × Apoe-/- mice). Conclusion: These results suggest that the beneficial effects of Fat- 1tg were mediated through ChemR23. Hence, omega-3 PUFA may have a therapeutic potential for reducing atherosclerotic plaque calcification through RvE1-signaling by means of ChemR23. [ABSTRACT FROM AUTHOR]

The first total synthesis of the lipid mediator MaR1 n−3 DPA ( 5) has been achieved in 12 % overall yield over 11 steps. The stereoselective preparation of 5 was based on a Pd-catalyzed sp3-sp3 Negishi cross-coupling reaction and a stereocontrolled Evans-Nagao acetate aldol reaction. LC-MS/MS results with synthetic material matched the biologically produced 5. This novel lipid mediator displayed potent pro-resolving properties stimulating macrophage efferocytosis of apoptotic neutrophils. [ABSTRACT FROM AUTHOR]

Human milk contains nutrients and bioactive products relevant to infant development and immunological protection. Here, we investigated the pro-resolving properties of milk using human milk lipid mediator isolates (HLMI) and determined their impact on resolution programs in vivo and with human macrophages. HLMI reduced maximum neutrophil numbers (14.6±1.2×106 to 11.0±1.0×106 cells/exudate) and shortened the resolution interval (Ri; 50% neutrophil reduction) 54% compared to peritonitis. Using rigorous liquid-chromatography tandem-mass spectrometry (LC-MS-MS)-based lipid mediator (LM) metabololipidomics, we demonstrated that human milk possesses a proresolving LM-SPM signature profile, containing specialized proresolving mediators (SPM; e.g. resolvins, protectins, maresins and lipoxins) at bioactive levels (pico-nanomolar concentrations) that enhanced human macrophage efferocytosis and bacterial containment. SPM identified in human milk included D-series resolvins, (e.g. Resolvin (Rv) D1, RvD2, RvD3, AT-RvD3 and RvD4), Protectin (PD)1, Maresin (MaR)1, E-series resolvins (e.g. RvE1, RvE2 and RvE3) and lipoxins (LXA4 and LXB4). Of the SPM identified in human milk, RvD2 and MaR1 (50 ng/mouse) individually shortened Ri ~75%. Milk from mastitis gave higher LTB4 and prostanoids and lower SPM levels. Taken together, these findings provide evidence that human milk has pro-resolving actions via comprehensive LM-SPM profiling, describing a potentially novel mechanism in maternal-infant biochemical imprinting.

Human milk contains nutrients and bioactive products relevant to infant development and immunological protection. Here, we investigated the proresolving properties of milk using human milk lipid mediator isolates (HLMIs) and determined their impact on resolution programs in vivo and with human macrophages. HLMIs reduced the maximum neutrophil numbers (14.6±1.2 × 10(6)-11.0±1.0 × 10(6) cells per exudate) and shortened the resolution interval (Ri; 50% neutrophil reduction) by 54% compared with peritonitis. Using rigorous liquid-chromatography tandem-mass spectrometry (LC-MS-MS)-based lipid mediator (LM) metabololipidomics, we demonstrated that human milk possesses a proresolving LM-specialized proresolving mediator (LM-SPM) signature profile, containing SPMs (e.g. resolvins (Rv), protectins (PDs), maresins (MaRs), and lipoxins (LXs)) at bioactive levels (pico-nanomolar concentrations) that enhanced human macrophage efferocytosis and bacterial containment. SPMs identified in human milk included D-series Rvs (e.g., RvD1, RvD2, RvD3, AT-RvD3, and RvD4), PD1, MaR1, E-series Rvs (e.g. RvE1, RvE2, and RvE3), and LXs (LXA4 and LXB4). Of the SPMs identified in human milk, RvD2 and MaR1 (50 ng per mouse) individually shortened Ri by ∼75%. Milk from mastitis gave higher leukotriene B4 and prostanoids and lower SPM levels. Taken together, these findings provide evidence that human milk has proresolving actions via comprehensive LM-SPM profiling, describing a potentially novel mechanism in maternal-infant biochemical imprinting.

Localized aggressive periodontitis (LAP) is a distinct form of early-onset periodontitis linked to periodontal infection with uncontrolled inflammation and leukocyte-mediated tissue destruction. The resolution of inflammation is an active process orchestrated by specialized proresolving lipid mediators (SPMs). Since the level of the Maresin pathway marker 14-hydroxy-docosahexaenoic acid (14-HDHA) was lower in activated peripheral blood from LAP patients, we investigated the Maresin 1 (MaR1) biosynthetic pathway in these subjects and its role in regulating phagocyte functions. Macrophages from LAP patients had a lower level of expression of 12-lipoxygenase (∼30%) and reduced MaR1 (LAP versus healthy controls [HC], 87.8 ± 50 pg/10(6) cells versus 239.1 ± 32 pg/10(6) cells). Phagocytosis by LAP macrophages was reduced ∼40% compared to that of HC, and killing of periodontal pathogens, including Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, were similarly reduced. LAP neutrophils also displayed slower kinetics (∼30%) and decreased maximal phagocytosis (∼20% lower) with these pathogens than those of HC. The administration of MaR1 at 1 nM enhanced phagocytosis (31 to 65% increase), intracellular antimicrobial reactive oxygen species production (26 to 71% increase), bacterial killing of these periodontal pathogens (22 to 38% reduction of bacterial titers), and restored impairment of LAP phagocytes. Together, these results suggest that therapeutics targeting the Maresin pathway have clinical utility in treating LAP and other oral diseases associated with infection, inflammation, and altered phagocyte functions., (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)

The first total synthesis of the lipid mediator MaR1n-3 DPA (5) has been achieved in 12 % overall yield over 11 steps. The stereoselective preparation of 5 was based on a Pd-catalyzed sp(3) -sp(3) Negishi cross-coupling reaction and a stereocontrolled Evans-Nagao acetate aldol reaction. LC-MS/MS results with synthetic material matched the biologically produced 5. This novel lipid mediator displayed potent pro-resolving properties stimulating macrophage efferocytosis of apoptotic neutrophils., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)