Self‐resolving inflammatory exudates and lipid mediator metabolomics recently uncovered a new family of potent anti‐inflammatory and proresolving mediators biosynthesized by macrophages (MΦs), ...denoted maresins. Here we determined that maresin 1 (MaR1) produced by human MΦs from endogenous docosahexaenoic acid (DHA) matched synthetic 7R,14S‐dihydroxydocosa‐4Z,8E,10E,12Z,16Z,19Z‐hexaenoic acid. The MaR1 alcohol groups and Z/E geometry of conjugated double bonds were matched using isomers prepared by total organic synthesis. MaR1's potent defining actions were confirmed with synthetic MaR1, i.e., limiting polymorphonuclear neutrophil (PMN) infiltration in murine peritonitis (ng/mouse range) as well as enhancing human macrophage uptake of apoptotic PMNs. At 1 nM, MaR1 was slightly more potent than resolvin D1 in stimulating human MΦ efferocytosis, an action not shared by leukotriene B4. MaR1 also accelerated surgical regeneration in planaria, increasing the rate of head reappearance. On injury of planaria, MaR1 was biosynthesized from deuterium‐labeled (d5)‐DHA that was blocked with lipoxygenase (LOX) inhibitor. MaR1 dose‐dependently inhibited TRPV1 currents in neurons, blocked capsaicin (100 nM)‐ induced inward currents (IC50 0.49±0.02 nM), and reduced both inflammation‐ and chemotherapy‐induced neuropathic pain in mice. These results demonstrate the potent actions of MaR1 in regulating inflammation resolution, tissue regeneration, and pain resolution. These findings suggest that chemical signals are shared in resolution cellular trafficking, a key process in tissue regeneration. Moreover, immunoresolvents of the innate immune response, such as MaR1, offer new opportunities for assessing MΦs and their local DHA metabolome in the return to tissue homeostasis.—Serhan, C. N., Dalli, J., Karamnov, S., Choi, A., Park, C.‐K., Xu, Z.‐Z., Ji, R.‐R., Zhu, M., Petasis, N. A. Macrophage proresolving mediator maresin 1 stimulates tissue regeneration and controls pain. FASEB J. 26, 1755‐1765 (2012). www.fasebj.org
Neuroprotectin D1 (NPD1) is a stereoselective mediator derived from the omega-3 essential fatty acid docosahexaenoic acid (DHA) with potent inflammatory resolving and neuroprotective bioactivity. ...NPD1 reduces Aβ42 peptide release from aging human brain cells and is severely depleted in Alzheimer's disease (AD) brain. Here we further characterize the mechanism of NPD1's neurogenic actions using 3xTg-AD mouse models and human neuronal-glial (HNG) cells in primary culture, either challenged with Aβ42 oligomeric peptide, or transfected with beta amyloid precursor protein (βAPP)(sw) (Swedish double mutation APP695(sw), K595N-M596L). We also show that NPD1 downregulates Aβ42-triggered expression of the pro-inflammatory enzyme cyclooxygenase-2 (COX-2) and of B-94 (a TNF-α-inducible pro-inflammatory element) and apoptosis in HNG cells. Moreover, NPD1 suppresses Aβ42 peptide shedding by down-regulating β-secretase-1 (BACE1) while activating the α-secretase ADAM10 and up-regulating sAPPα, thus shifting the cleavage of βAPP holoenzyme from an amyloidogenic into the non-amyloidogenic pathway. Use of the thiazolidinedione peroxisome proliferator-activated receptor gamma (PPARγ) agonist rosiglitazone, the irreversible PPARγ antagonist GW9662, and overexpressing PPARγ suggests that the NPD1-mediated down-regulation of BACE1 and Aβ42 peptide release is PPARγ-dependent. In conclusion, NPD1 bioactivity potently down regulates inflammatory signaling, amyloidogenic APP cleavage and apoptosis, underscoring the potential of this lipid mediator to rescue human brain cells in early stages of neurodegenerations.
Endogenous mechanisms that act in the resolution of acute inflammation are essential for host defense and the return to homeostasis. Resolvin D1 (RvD1), biosynthesized during resolution, displays ...potent and stereoselective anti-inflammatory actions, such as limiting neutrophil infiltration and proresolving actions. Here, we demonstrate that RvD1 actions on human polymorphonuclear leukocytes (PMNs) are pertussis toxin sensitive, decrease actin polymerization, and block LTB₄-regulated adhesion molecules (β2 integrins). Synthetic ³H-RvD1 was prepared, which revealed specific RvD1 recognition sites on human leukocytes. Screening systems to identify receptors for RvD1 gave two candidates--ALX, a lipoxin A₄ receptor, and GPR32, an orphan--that were confirmed using a β-arrestin-based ligand receptor system. Nuclear receptors including retinoid X receptor-α and peroxisome proliferator-activated receptor-α, -δ, -γ were not activated by either resolvin E1 or RvD1 at bioactive nanomolar concentrations. RvD1 enhanced macrophage phagocytosis of zymosan and apoptotic PMNs, which increased with overexpression of human ALX and GPR32 and decreased with selective knockdown of these G-protein-coupled receptors. Also, ALX and GPR32 surface expression in human monocytes was up-regulated by zymosan and granulocyte-monocyte-colony-stimulating factor. These results indicate that RvD1 specifically interacts with both ALX and GPR32 on phagocytes and suggest that each plays a role in resolving acute inflammation.
Structure-based virtual ligand screening is emerging as a key paradigm for early drug discovery owing to the availability of high-resolution target structures
and ultra-large libraries of virtual ...compounds
. However, to keep pace with the rapid growth of virtual libraries, such as readily available for synthesis (REAL) combinatorial libraries
, new approaches to compound screening are needed
. Here we introduce a modular synthon-based approach-V-SYNTHES-to perform hierarchical structure-based screening of a REAL Space library of more than 11 billion compounds. V-SYNTHES first identifies the best scaffold-synthon combinations as seeds suitable for further growth, and then iteratively elaborates these seeds to select complete molecules with the best docking scores. This hierarchical combinatorial approach enables the rapid detection of the best-scoring compounds in the gigascale chemical space while performing docking of only a small fraction (<0.1%) of the library compounds. Chemical synthesis and experimental testing of novel cannabinoid antagonists predicted by V-SYNTHES demonstrated a 33% hit rate, including 14 submicromolar ligands, substantially improving over a standard virtual screening of the Enamine REAL diversity subset, which required approximately 100 times more computational resources. Synthesis of selected analogues of the best hits further improved potencies and affinities (best inhibitory constant (K
) = 0.9 nM) and CB
/CB
selectivity (50-200-fold). V-SYNTHES was also tested on a kinase target, ROCK1, further supporting its use for lead discovery. The approach is easily scalable for the rapid growth of combinatorial libraries and potentially adaptable to any docking algorithm.
Protein disulfide isomerase (PDI), an endoplasmic reticulum chaperone protein, catalyzes disulfide bond breakage, formation, and rearrangement. The effect of PDI inhibition on ovarian cancer ...progression is not yet clear, and there is a need for potent, selective, and safe small-molecule inhibitors of PDI. Here, we report a class of propynoic acid carbamoyl methyl amides (PACMAs) that are active against a panel of human ovarian cancer cell lines. Using fluorescent derivatives, 2D gel electrophoresis, and MS, we established that PACMA 31, one of the most active analogs, acts as an irreversible small-molecule inhibitor of PDI, forming a covalent bond with the active site cysteines of PDI. We also showed that PDI activity is essential for the survival and proliferation of human ovarian cancer cells. In vivo, PACMA 31 showed tumor targeting ability and significantly suppressed ovarian tumor growth without causing toxicity to normal tissues. These irreversible small-molecule PDI inhibitors represent an important approach for the development of targeted anticancer agents for ovarian cancer therapy, and they can also serve as useful probes for investigating the biology of PDI-implicated pathways.
A one-step, three-component condensation of allenyl boronic acids or allenyl pinacolboronates with amines and aldehydes affords α-allenyl or α-propargyl α-amino acids and anti-β-amino alcohols. This ...process gives the allenyl or propargyl product depending on the amine and boron components. Secondary amines generate exclusively α-allenyl α-amino acids, while primary aliphatic amines lead to α-propargyl α-amino acids. Secondary aliphatic amines react with chiral α-hydroxy aldehydes and allenyl boron derivatives to form stereoselectively allenyl anti-β-amino alcohol products.
Macrophages are central in coordinating immune responses, tissue repair, and regeneration, with different subtypes being associated with inflammation-initiating and proresolving actions. We recently ...identified a family of macrophage-derived proresolving and tissue regenerative molecules coined maresin conjugates in tissue regeneration (MCTR). Herein, using lipid mediator profiling we identified MCTR in human serum, lymph nodes, and plasma and investigated MCTR biosynthetic pathways in human macrophages. With human recombinant enzymes, primary cells, and enantiomerically pure compounds we found that the synthetic maresin epoxide intermediate 13S,14S-eMaR (13S,14S-epoxy- 4Z,7Z,9E,11E,16Z,19Z-docosahexaenoic acid) was converted to MCTR1 (13R-glutathionyl, 14S-hydroxy-4Z,7Z,9E,11E,13R,14S,16Z,19Z-docosahexaenoic acid) by LTC₄S and GSTM4. Incubation of human macrophages with LTC₄S inhibitors blocked LTC₄ and increased resolvins and lipoxins. The conversion of MCTR1 to MCTR2 (13R-cysteinylglycinyl, 14S-hydroxy-4Z,7Z,9E,11E,13R,14S,16Z,19Z-docosahexaenoic acid) was catalyzed by γ-glutamyl transferase (GGT) in human macrophages. Biosynthesis of MCTR3 was mediated by dipeptidases that cleaved the cysteinyl-glycinyl bond of MCTR2 to give 13R-cysteinyl, 14S-hydroxy-4Z,7Z,9E,11E,13R,14S,16Z,19Z-docosahexaenoic acid. Of note, both GSTM4 and GGT enzymes displayed higher affinity to 13S,14S-eMaR and MCTR1 compared with their classic substrates in the cysteinyl leukotriene metabolome. Together these results establish the MCTR biosynthetic pathway and provide mechanisms in tissue repair and regeneration.
Unregulated acute inflammation can lead to collateral tissue injury in vital organs, such as the lung during the acute respiratory distress syndrome. In response to tissue injury, circulating ...platelet–neutrophil aggregates form to augment neutrophil tissue entry. These early cellular events in acute inflammation are pivotal to timely resolution by mechanisms that remain to be elucidated. Here, we identified a previously undescribed biosynthetic route during human platelet–neutrophil interactions for the proresolving mediator maresin 1 (MaR1; 7R,14S-dihydroxy-docosa-4Z,8E,10E,12Z,16Z,19Z-hexaenoic acid). Docosahexaenoic acid was converted by platelet 12-lipoxygenase to 13S,14S-epoxy-maresin, which was further transformed by neutrophils to MaR1. In a murine model of acute respiratory distress syndrome, lipid mediator metabololipidomics uncovered MaR1 generation in vivo in a temporally regulated manner. Early MaR1 production was dependent on platelet–neutrophil interactions, and intravascular MaR1 was organ-protective, leading to decreased lung neutrophils, edema, tissue hypoxia, and prophlogistic mediators. Together, these findings identify a transcellular route for intravascular maresin 1 biosynthesis via platelet–neutrophil interactions that regulates the extent of lung inflammation.
Significance Neutrophil accumulation is fundamental to acute inflammation. In response to tissue injury, circulating neutrophil–platelet aggregates (N-PAs) form for secondary capture. Counterregulation of acute inflammatory processes by specialized proresolving mediators is essential to mitigate collateral injury to healthy bystander tissue. Here, we identified a biosynthetic route in human platelets for the proresolving mediator maresin 1 (MaR1) that is amplified during platelet–neutrophil interactions. In a self-resolving murine model of acute lung injury, N-PAs rapidly formed and a MaR1 counterregulatory circuit was engaged to restrain N-PAs and acute inflammation and restore homeostasis of the injured lung.
The essential fatty acid eicosapentaenoic acid (EPA) present in fish oils displays beneficial effects in a range of human disorders associated with inflammation including cardiovascular disease. ...Resolvin E1 (RvE1), a new bioactive oxygenated product of EPA, was identified in human plasma and prepared by total organic synthesis. Results of bioaction and physical matching studies indicate that the complete structure of RvE1 is 5S,12R,18R-trihydroxy-6Z,8E,10E,14Z,16E-EPA. At nanomolar levels, RvE1 dramatically reduced dermal inflammation, peritonitis, dendritic cell (DC) migration, and interleukin (IL) 12 production. We screened receptors and identified one, denoted earlier as ChemR23, that mediates RvE1 signal to attenuate nuclear factor-kappaB. Specific binding of RvE1 to this receptor was confirmed using synthetic (3)H-labeled RvE1. Treatment of DCs with small interference RNA specific for ChemR23 sharply reduced RvE1 regulation of IL-12. These results demonstrate novel counterregulatory responses in inflammation initiated via RvE1 receptor activation that provide the first evidence for EPA-derived potent endogenous agonists of antiinflammation.
PDF
