Inflammatory Lipid Mediators Research Articles

Modulating immunometabolism in transition dairy cows: the role of inflammatory lipid mediators.

Modulating immunometabolism in transition dairy cows: the role of inflammatory lipid mediators.

Transcellular biosynthesis of leukotriene B4 orchestrates neutrophil swarming to fungi

SummaryNeutrophil swarming is an emergent host defense mechanism triggered by targets larger than a single neutrophil’s capacity to phagocytose. Swarming synergizes neutrophil functions, including chemotaxis, phagocytosis, and reactive oxygen species (ROS) production, and coordinates their deployment by many interacting neutrophils. The potent inflammatory lipid mediator leukotriene B4 (LTB4) has been established as central to orchestrating neutrophil activities during swarming. However, the details regarding how this eicosanoid choreographs the neutrophils involved in swarming are not well explained. Here we leverage microfluidics, genetically deficient mouse cells, and targeted metabolipidomic analysis to demonstrate that transcellular biosynthesis occurs among neutrophils to generate LTB4. Furthermore, transcellular biosynthesis is an entirely sufficient means of generating LTB4 for the purposes of orchestrating neutrophil swarming. These results further our understanding of how neutrophils coordinate their activities during swarming, which will be critical in the design of eventual therapies that can harness the power of swarming behavior.

Effects of Different Routes and Forms of Vitamin D Administration on Mesenteric Lymph Node CD4+ T Cell Polarization and Intestinal Injury in Obese Mice Complicated with Polymicrobial Sepsis.

This study compared the efficacies of enteral cholecalciferol and/or intravenous (IV) calcitriol administration on mesenteric lymph node (MLN) cluster-of-differentiation-4-positive (CD4+) T cell distribution and intestinal barrier damage in obese mice complicated with sepsis. Mice were fed a high-fat diet for 16 weeks and then sepsis was induced by cecal ligation and puncture (CLP). Mice were divided into the following sepsis groups: without vitamin D (VD) (S); with oral cholecalciferol 1 day before CLP (G); with IV calcitriol 1 h after CLP (V); and with both cholecalciferol before and IV calcitriol after CLP (GV). All mice were sacrificed at 12 or 24 h after CLP. The findings show that the S group had a higher T helper (Th)17 percentage than the VD-treated groups at 12 h after CLP. The V group exhibited a higher Th1 percentage and Th1/Th2 ratio than the other groups at 24 h, whereas the V and GV groups had a lower Th17/regulatory T (Treg) ratio 12 h post-CLP in MLNs. In ileum tissues, the VD-treated groups had higher tight junction protein and cathelicidin levels, and higher mucin gene expression than the S group at 24 h post-CLP. Also, aryl hydrocarbon receptor (AhR) and its associated cytochrome P450 1A1 and interleukin 22 gene expressions were upregulated. In contrast, levels of lipid peroxides and inflammatory mediators in ileum tissues were lower in the groups with VD treatment after CLP. These results suggest that IV calcitriol seemed to have a more-pronounced effect on modulating the homeostasis of Th/Treg subsets in MLNs. Both oral cholecalciferol before and IV calcitriol after CLP promoted cathelicidin secretion, alleviated intestinal inflammation, and ameliorated the epithelial integrity in obese mice complicated with sepsis possibly via VD receptor and AhR signaling pathways.

Decrypting the cellular and molecular intricacies associated with COVID-19-induced chronic pain.

Pain is one of the clinical manifestations that can vary from mild to severe symptoms in COVID-19 patients. Pain symptoms can be initiated by direct viral damage to the tissue or by indirect tissue injury followed by nociceptor sensitization. The most common types of pain that are reported to occur in COVID-19 patients are headache, myalgia, and chest pain. With more and more cases coming in the hospitals, many new and unique symptoms of pain are being reported. Testicular and abdominal pain are rare cases of pain that are also being reported and are associated with COVID-19. The SARS-CoV-2 virus has a high affinity for angiotensin-converting enzyme-2 receptor (ACE-2) which acts as an entry point for the virus. ACE-2/ Ang II/AT 1 receptor also participates directly in the transmission of pain signals from the dorsal horn of the spinal cord. It induces a series of complicated responses in the human body. Among which the cytokinetic storm and hypercoagulation are the most prominent pathways that mediate the sensitization of sensory neurons facilitating pain. The elevated immune response is also responsible for the activation of inflammatory lipid mediators such as COX-1 and COX-2 enzymes for the synthesis of prostaglandins (PGs). PG molecules especially PGE2 and PGD2 are involved in the pain transmission and are found to be elevated in COVID-19 patients. Though arachidonic acid pathway is one of the lesser discussed topics in COVID-19 pathophysiology, still it can be useful for explaining the unique and rarer symptoms of pain seen in COVID-19 patients. Understanding different pain pathways is very crucial for the management of pain and can help healthcare systems to end the current pandemic situation. We herein review the role of various molecules involved in the pain pathology of COVID-19.

Cytokines and Lipid Mediators of Inflammation in Lungs of SARS-CoV-2 Infected Mice.

Coronavirus disease 19 (COVID-19) is the clinical manifestation of severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) infection. A hallmark of COVID-19 is a lung inflammation characterized by an abundant leukocyte infiltrate, elevated levels of cytokines/chemokines, lipid mediators of inflammation (LMI) and microthrombotic events. Animal models are useful for understanding the pathophysiological events leading to COVID-19. One such animal model is the K18-ACE2 transgenic mice. Despite their importance in inflammation, the study of LMI in lung of SARS-CoV-2 infected K18-ACE2 mice has yet to be studied to our knowledge. Using tandem mass spectrometry, the lung lipidome at different time points of infection was analyzed. Significantly increased LMI included N-oleoyl-serine, N-linoleoyl-glycine, N-oleoyl-alanine, 1/2-linoleoyl-glycerol, 1/2-docosahexaenoyl-glycerol and 12-hydroxy-eicosapenatenoic acid. The levels of prostaglandin (PG) E1, PGF2α, stearoyl-ethanolamide and linoleoyl-ethanolamide were found to be significantly reduced relative to mock-infected mice. Other LMI were present at similar levels (or undetected) in both uninfected and infected mouse lungs. In parallel to LMI measures, transcriptomic and cytokine/chemokine profiling were performed. Viral replication was robust with maximal lung viral loads detected on days 2-3 post-infection. Lung histology revealed leukocyte infiltration starting on day 3 post-infection, which correlated with the presence of high concentrations of several chemokines/cytokines. At early times post-infection, the plasma of infected mice contained highly elevated concentration of D-dimers suggestive of blood clot formation/dissolution. In support, the presence of blood clots in the lung vasculature was observed during infection. RNA-Seq analysis of lung tissues indicate that SARS-CoV-2 infection results in the progressive modulation of several hundred genes, including several inflammatory mediators and genes related to the interferons. Analysis of the lung lipidome indicated modest, yet significant modulation of a minority of lipids. In summary, our study suggests that SARS-CoV-2 infection in humans and mice share common features, such as elevated levels of chemokines in lungs, leukocyte infiltration and increased levels of circulating D-dimers. However, the K18-ACE2 mouse model highlight major differences in terms of LMI being produced in response to SARS-CoV-2 infection. The potential reasons and impact of these differences on the pathology and therapeutic strategies to be employed to treat severe COVID-19 are discussed.

Modulatory action of withaferin-A on oxidative damage through regulation of inflammatory mediators and apoptosis via PI3K/AKT signaling pathway in high cholesterol-induced atherosclerosis in experimental rats.

Statins are widely used lipid-lowering drugs that cause many side effects. Withaferin-A (WA), popularly known as Ashwagandha, an ancient Indian medicinal herb, is extracted from Withania somnifera. Anti-atherosclerotic effect of WA has been reported. However, the mechanism remains unknown. Hence, we planned this study to investigate the WA mechanism in anti-atherosclerosis in a rat model. High cholesterol diet (HCD) was fed to induce atherosclerosis in Sprague-Dawley male rats. Five groups (N = 6 rats/group) were fed with normal diet, HCD, WA (10 mg/kg bw)+HCD, lovastatin (LS: 10 mg/kg bw)+HCD, WA (10 mg/kg bw) respectively for 90 days. Statistical analysis was done by GraphPad Prism (version 8.0.1) using one-way analysis of variance (ANOVA) followed by post hoc Duncan's test with a significance level (p < 0.05). The groups were compared for lipid profiles, oxidative stress, lipid peroxidation, inflammatory mediators, apoptotic markers, and histopathological changes in the liver and aorta. Treatment with HCD increased lipid profiles, inflammatory mediators, cytokines, and lipid peroxidation. WAas well as LS treatmentssignificantly decreased these parameters restored the antioxidant status, and reduced lipid peroxidation (p < 0.05). Histopathological studies revealed that WA and LS reduced the hepatic fat and aortic plaque. WA reduced apoptosis via augmentation of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway; increased B-cell lymphoma 2 and inhibited Bcl-2 associated X-protein proapoptotic proteins; TNF receptor superfamily member 6, Bim, caspase-3, and -9; demonstrated significant hypolipidemic and anti-inflammatory properties against HCD induced atherosclerosis in rats through regulation of inflammatory mediators and apoptosis via thePI3K/AKT signaling pathway.

Evaluation of antiobesity and hepatorenal protective activities of Salvia officinalis extracts pre-treatment in high-fat diet-induced obese rats.

The present study evaluated the effects of Hail Salvia officinalis total extract (SOTE) and its high flavonoid fraction (SOHFF) on the high-fat diet (HFD)-induced obesity and hepatorenal damage in rats. Salvia officinalisplants were collected from Hail region, Saudi Arabia. Rats were fed HFD and supplemented orally with SOTE (250mgkg-1) or SOHFF (100mgkg-1) or simvastatin (SVS; 10mgkg-1) every day for 8weeks. Compared to the controls, HFD-induced obesity led to significant increases in body weight, body weight gained, blood insulin, leptin, cardiac enzymes (LDH and CPK) activity, and atherogenic index (AI). HFD rats also showed higher levels of hepatic and renal function biomarkers (ALT, urea, and creatinine), as well as lower levels of PPARγ and Nrf2-gene expression and a disrupted lipid profile. Moreover, HFD rats had lower levels of hepatic and renal antioxidant biomarkers (CAT, GPx, SOD, GR, and GSH), accompanied by higher levels of hepatic and renal lipid peroxidation (LPO), nitric oxide (NO), and inflammatory mediators (interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α)). In addition, histological examination of hepatic and renal tissues revealed histopathological changes that validated the biochemical findings. Compared to HFD group, SOTE and SOHFF treatment led to marked amelioration of all the aforementioned parameters. Collectively, supplementation with SOTE and SOHFF effectively reversed HFD-induced alterations through its antioxidant, hypolipidemic, and anti-inflammatory properties. Hence, SOTE and SOHFF have therapeutic potential in controlling obesity and related pathologies.

Novel aerosol treatment of airway hyper-reactivity and inflammation in a murine model of asthma with a soluble epoxide hydrolase inhibitor.

Asthma currently affects more than 339 million people worldwide. In the present preliminary study, we examined the efficacy of a new, inhalable soluble epoxide hydrolase inhibitor (sEHI), 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU), to attenuate airway inflammation, mucin secretion, and hyper-responsiveness (AHR) in an ovalbumin (OVA)-sensitized murine model. Male BALB/c mice were divided into phosphate-buffered saline (PBS), OVA, and OVA+TPPU (2- or 6-h) exposure groups. On days 0 and 14, the mice were administered PBS or sensitized to OVA in PBS. From days 26-38, seven challenge exposures were performed with 30 min inhalation of filtered air or OVA alone. In the OVA+TPPU groups, a 2- or 6-h TPPU inhalation preceded each 30-min OVA exposure. On day 39, pulmonary function tests (PFTs) were performed, and biological samples were collected. Lung tissues were used to semi-quantitatively evaluate the severity of inflammation and airway constriction and the volume of stored intracellular mucosubstances. Bronchoalveolar lavage (BAL) and blood samples were used to analyze regulatory lipid mediator profiles. Significantly (p < 0.05) attenuated alveolar, bronchiolar, and pleural inflammation; airway resistance and constriction; mucosubstance volume; and inflammatory lipid mediator levels were observed with OVA+TPPU relative to OVA alone. Cumulative findings indicated TPPU inhalation effectively inhibited inflammation, suppressed AHR, and prevented mucosubstance accumulation in the murine asthmatic model. Future studies should determine the pharmacokinetics (i.e., absorption, distribution, metabolism, and excretion) and pharmacodynamics (i.e., concentration/dose responses) of inhaled TPPU to explore its potential as an asthma-preventative or -rescue treatment.

Clr-f expression regulates kidney immune and metabolic homeostasis

The C-type lectin-related protein, Clr-f, encoded by Clec2h in the mouse NK gene complex (NKC), is a member of a family of immune regulatory lectins that guide immune responses at distinct tissues of the body. Clr-f is highly expressed in the kidney; however, its activity in this organ is unknown. To assess the requirement for Clr-f in kidney health and function, we generated a Clr-f-deficient mouse (Clr-f−/−) by targeted deletions in the Clec2h gene. Mice lacking Clr-f exhibited glomerular and tubular lesions, immunoglobulin and C3 complement protein renal deposits, and significant abdominal and ectopic lipid accumulation. Whole kidney transcriptional profile analysis of Clr-f−/− mice at 7, 13, and 24 weeks of age revealed a dynamic dysregulation in lipid metabolic processes, stress responses, and inflammatory mediators. Examination of the immune contribution to the pathologies of Clr-f−/− mouse kidneys identified elevated IL-12 and IFNγ in cells of the tubulointerstitium, and an infiltrating population of neutrophils and T and B lymphocytes. The presence of these insults in a Rag1−/−Clr-f−/− background reveals that Clr-f−/− mice are susceptible to a T and B lymphocyte-independent renal pathogenesis. Our data reveal a role for Clr-f in the maintenance of kidney immune and metabolic homeostasis.

LSEA Evaluation of Lipid Mediators of Inflammation in Lung and Cortex of Mice Exposed to Diesel Air Pollution.

Airborne ultrafine particle (UFP) exposure is a great concern as they have been correlated to increased cardiovascular mortality, neurodegenerative diseases and morbidity in occupational and environmental settings. The ultrafine components of diesel exhaust particles (DEPs) represent about 25% of the emission mass; these particles have a great surface area and consequently high capacity to adsorb toxic molecules, then transported throughout the body. Previous in-vivo studies indicated that DEP exposure increases pro- and antioxidant protein levels and activates inflammatory response both in respiratory and cardiovascular systems. In cells, DEPs can cause additional reactive oxygen species (ROS) production, which attacks surrounding molecules, such as lipids. The cell membrane provides lipid mediators (LMs) that modulate cell-cell communication, inflammation, and resolution processes, suggesting the importance of understanding lipid modifications induced by DEPs. In this study, with a lipidomic approach, we evaluated in the mouse lung and cortex how DEP acute and subacute treatments impact polyunsaturated fatty acid-derived LMs. To analyze the data, we designed an ad hoc bioinformatic pipeline to evaluate the functional enrichment of lipid sets belonging to the specific biological processes (Lipid Set Enrichment Analysis-LSEA). Moreover, the data obtained correlate tissue LMs and proteins associated with inflammatory process (COX-2, MPO), oxidative stress (HO-1, iNOS, and Hsp70), involved in the activation of many xenobiotics as well as PAH metabolism (Cyp1B1), suggesting a crucial role of lipids in the process of DEP-induced tissue damage.

Plasma Oxylipin Profile Discriminates Ethnicities in Subjects with Non-Alcoholic Steatohepatitis: An Exploratory Analysis.

Non-alcoholic fatty liver disease (NAFLD) is a common liver pathology that includes steatosis, or non-alcoholic fatty liver (NAFL), and non-alcoholic steatohepatitis (NASH). Without a clear pathophysiological mechanism, it affects Hispanics disproportionately compared to other ethnicities. Polyunsaturated fatty acids (PUFAs) and inflammatory lipid mediators including oxylipin (OXL) and endocannabinoid (eCB) are altered in NAFLD and thought to contribute to its pathogenesis. However, the existence of ethnicity-related differences is not clear. We employed targeted lipidomic profiling for plasma PUFAs, non-esterified OXLs and eCBs in White Hispanics (HIS, n = 10) and Caucasians (CAU, n = 8) with biopsy-confirmed NAFL, compared with healthy control subjects (HC; n = 14 HIS; n = 8 CAU). NAFLD was associated with diminished long chain PUFA in HIS, independent of histological severity. Differences in plasma OXLs and eCBs characterized ethnicities in NASH, with lower arachidonic acid derived OXLs observed in HIS. The secondary analysis comparing ethnicities within NASH (n = 12 HIS; n = 17 CAU), confirms these ethnicity-related differences and suggests lower lipoxygenase(s) and higher soluble epoxide hydrolase(s) activities in HIS compared to CAU. While causes are not clear, these lipidomic differences might be with implications for NAFLD severity and are worth further investigation. We provide preliminary data indicating ethnicity-specific lipidomic signature characterizes NASH which requires further validation.

Siglec-F Promotes IL-33-Induced Cytokine Release from Bone Marrow-Derived Eosinophils Independently of the ITIM and ITIM-like Motif Phosphorylation.

Eosinophils are potent innate effector cells associated mainly with type 2 immune responses elicited by helminths and allergens. Their activity needs to be tightly controlled to prevent severe inflammation and tissue damage. Eosinophil degranulation and secretion of inflammatory effector molecules, including cytokines, chemokines, and lipid mediators, can be regulated by activating and inhibitory receptors on the cell surface. In this study, we investigated the modulation of proliferation, apoptosis, gene expression, and cytokine/chemokine secretion from IL-33-activated Mus musculus eosinophils on cross-linking of the transmembrane receptor Sialic acid-binding Ig-like lectin F (Siglec-F). Siglec-F contains an ITIM plus an ITIM-like motif in its intracellular tail and is mainly regarded as an inhibitory and apoptosis-inducing receptor. In vitro costimulation of bone marrow-derived eosinophils with anti-Siglec-F and IL-33 compared with treatment with either alone led to enhanced STAT6 phosphorylation, stronger induction of hypoxia/glycolysis-related proinflammatory genes, and elevated secretion of type 2 cytokines (IL-4, IL-13) and chemokines (CCL3, CCL4) with only minor effects on proliferation and apoptosis. Using a competitive mixed bone marrow chimera approach with wild-type and Siglec-F-deficient eosinophils, we observed no evidence for Siglec-F-regulated inhibition of Aspergillus fumigatus-elicited lung eosinophilia. Truncation of the Siglec-F cytoplasmic tail, but not mutation of the ITIM and ITIM-like motifs, ablated the effect of enhanced cytokine/chemokine secretion. This provides evidence for an ITIM phosphorylation-independent signaling pathway from the cytoplasmic tail of the Siglec-F receptor that enhances effector molecule release from activated eosinophils.

Role of Thymus and Activation-Regulated Chemokine in Allergic Asthma.

BackgroundAsthma is a chronic inflammatory airway disease characterized by the predominant infiltration of inflammatory cells in the airways. Thymus and activation-regulated chemokine/C–C motif chemokine 17 (TARC/CCL17) is a chemokine responsible for trafficking T helper 2 cells into sites of allergic inflammation.ObjectiveTo validate the role of TARC in association with clinical and inflammatory parameters in adult asthmatics.MethodsWe enrolled 128 asthmatic patients and 70 healthy controls (HCs). Asthma-related clinical and laboratory parameters, including lung function and eosinophil counts, were measured. Serum levels of TARC, free immunoglobulin E (IgE), and eosinophil-derived neurotoxin (EDN) were determined by using enzyme-linked immunosorbent assay; serum total IgE level was measured using ImmunoCAP. The levels of inflammatory lipid mediators, such as leukotriene E4 (LTE4), 15-hydroxyeicosatetraenoic acid (15-HETE), thromboxane B2 (TXB2), and prostaglandin F2α (PGF2α), were measured by liquid chromatography-tandem mass spectrometry.ResultsSerum TARC levels are significantly higher in asthmatics than in HCs and in allergic asthmatics than in HCs (P < 0.010 for all), with significantly negative correlations between serum TARC levels and FEV1%/MMEF% values (r = −0.314, r = −0.268, P < 0.050 for both). The patients with higher serum TARC levels had higher levels of serum total and free IgE levels (P < 0.050 for both) with positive correlations to serum levels of EDN, TXB2, and 15-HETE (r = 0.233, r = 0.264, and r = 0.223, respectively, P < 0.050 for all).ConclusionWe suggest the role of TARC in allergic asthma via contributing to mast cell and eosinophilic inflammation.

Nampt activator P7C3 ameliorates diabetes and improves skeletal muscle function modulating cell metabolism and lipid mediators.

BackgroundNicotinamide phosphoribosyltransferase (Nampt), a key enzyme in NAD salvage pathway is decreased in metabolic diseases, and its precise role in skeletal muscle function is not known. We tested the hypothesis, Nampt activation by P7C3 (3,6‐dibromo‐α‐[(phenylamino)methyl]‐9H‐carbazol‐9‐ethanol) ameliorates diabetes and muscle function.MethodsWe assessed the functional, morphometric, biochemical, and molecular effects of P7C3 treatment in skeletal muscle of type 2 diabetic (db/db) mice. Nampt+/− mice were utilized to test the specificity of P7C3.ResultsInsulin resistance increased 1.6‐fold in diabetic mice compared with wild‐type mice and after 4 weeks treatment with P7C3 rescued diabetes (P < 0.05). In the db‐P7C3 mice fasting blood glucose levels decreased to 0.96‐fold compared with C57Bl/6J wild‐type naïve control mice. The insulin and glucose tolerance tests blood glucose levels were decreased to 0.6‐fold and 0.54‐folds, respectively, at 120 min along with an increase in insulin secretion (1.76‐fold) and pancreatic β‐cells (3.92‐fold) in db‐P7C3 mice. The fore‐limb and hind‐limb grip strengths were increased to 1.13‐fold and 1.17‐fold, respectively, together with a 14.2‐fold increase in voluntary running wheel distance in db‐P7C3 mice. P7C3 treatment resulted in a 1.4‐fold and 7.1‐fold increase in medium‐sized and larger‐sized myofibres cross‐sectional area, with a concomitant 0.5‐fold decrease in smaller‐sized myofibres of tibialis anterior (TA) muscle. The transmission electron microscopy images also displayed a 1.67‐fold increase in myofibre diameter of extensor digitorum longus muscle along with 2.9‐fold decrease in mitochondrial area in db‐P7C3 mice compared with db‐Veh mice. The number of SDH positive myofibres were increased to 1.74‐fold in db‐P7C3 TA muscles. The gastrocnemius and TA muscles displayed a decrease in slow oxidative myosin heavy chain type1 (MyHC1) myofibres expression (0.46‐fold) and immunostaining (6.4‐fold), respectively. qPCR analysis displayed a 2.9‐fold and 1.3‐fold increase in Pdk4 and Cpt1, and 0.55‐fold and 0.59‐fold decrease in Fgf21 and 16S in db‐P7C3 mice. There was also a 3.3‐fold and 1.9‐fold increase in Fabp1 and CD36 in db‐Veh mice. RNA‐seq differential gene expression volcano plot displayed 1415 genes to be up‐regulated and 1726 genes down‐regulated (P < 0.05) in db‐P7C3 mice. There was 1.02‐fold increase in serum HDL, and 0.9‐fold decrease in low‐density lipoprotein/very low‐density lipoprotein ratio in db‐P7C3 mice. Lipid profiling of gastrocnemius muscle displayed a decrease in inflammatory lipid mediators n‐6; AA (0.83‐fold), and n‐3; DHA (0.69‐fold) and EPA (0.81‐fold), and a 0.66‐fold decrease in endocannabinoid 2‐AG and 2.0‐fold increase in AEA in db‐P7C3 mice.ConclusionsOverall, we demonstrate that P7C3 activates Nampt, improves type 2 diabetes and skeletal muscle function in db/db mice.

Drug delivery of 6-bromoindirubin-3\u2019-glycerol-oxime ether employing poly(d,l-lactide-co-glycolide)-based nanoencapsulation techniques with sustainable solvents

BackgroundInsufficient solubility and stability of bioactive small molecules as well as poor biocompatibility may cause low bioavailability and are common obstacles in drug development. One example of such problematic molecules is 6-bromoindirubin-3'-glycerol-oxime ether (6BIGOE), a hydrophobic indirubin derivative. 6BIGOE potently modulates the release of inflammatory cytokines and lipid mediators from isolated human monocytes through inhibition of glycogen synthase kinase-3 in a favorable fashion. However, 6BIGOE suffers from poor solubility and short half-lives in biological aqueous environment and exerts cytotoxic effects in various mammalian cells. In order to overcome the poor water solubility, instability and cytotoxicity of 6BIGOE, we applied encapsulation into poly(d,l-lactide-co-glycolide) (PLGA)-based nanoparticles by employing formulation methods using the sustainable solvents Cyrene™ or 400 g/mol poly(ethylene glycol) as suitable technology for efficient drug delivery of 6BIGOE.ResultsFor all preparation techniques the physicochemical characterization of 6BIGOE-loaded nanoparticles revealed comparable crystallinity, sizes of about 230 nm with low polydispersity, negative zeta potentials around − 15 to − 25 mV, and biphasic release profiles over up to 24 h. Nanoparticles with improved cellular uptake and the ability to mask cytotoxic effects of 6BIGOE were obtained as shown in human monocytes over 48 h as well as in a shell-less hen’s egg model. Intriguingly, encapsulation into these nanoparticles fully retains the anti-inflammatory properties of 6BIGOE, that is, favorable modulation of the release of inflammation-relevant cytokines and lipid mediators from human monocytes.ConclusionsOur formulation method of PLGA-based nanoparticles by applying sustainable, non-toxic solvents is a feasible nanotechnology that circumvents the poor bioavailability and biocompatibility of the cargo 6BIGOE. This technology yields favorable drug delivery systems for efficient interference with inflammatory processes, with improved pharmacotherapeutic potential.Graphical

Fatty Acid Oxidation and Pro-Resolving Lipid Mediators Are Related to Male Infertility.

Specialized pro-resolving lipid mediators regulate the resolution of acute inflammation. They are formed by enzymatic oxygenation of polyunsaturated fatty acids and are divided into families including lipoxins, resolvins, protectins, and maresins. Resolvin D1 (RvD1), produced by docosahexaenoic acid, exerts anti-inflammatory and pro-resolving activities. This research aimed to investigate the implication of seminal RvD1 in human infertility. Infertile patients (n° 67) were grouped based on pathological reproductive conditions as idiopathic infertility, varicocele, and leukocytospermia; the fourth group was composed of fertile men (n° 18). Sperm characteristics were evaluated by light microscopy (WHO guidelines) and by transmission electron microscopy (TEM). The seminal levels of RvD1 and F2-isoprostane (F2-IsoPs) were dosed. In twenty men (6 fertile men, 8 with varicocele, 6 with leukocytospermia) seminal phospholipase A2, iron, cholesterol, transferrin, estradiol, ferritin, testosterone, and sperm membrane fatty acids were detected. The results indicated that: (i) RvD1 amount was positively correlated with F2-IsoPs and reduced sperm quality; (ii) RvD1 levels were significantly higher in patients with leukocytospermia, varicocele, and idiopathic infertility compared to fertile men; (iii) RvD1 increased along with other markers of oxidative stress and inflammation as fatty acids content and clinical biomarkers. This study suggests a panel of inflammatory markers and lipid mediators for a diagnosis of inflammatory status and a subsequent appropriate therapeutic approach.

NAD+-boosting molecules suppress mast cell degranulation and anaphylactic responses in mice.

Nicotinamide adenine dinucleotide (NAD+) acts as a cofactor for multiple biological processes. While previous research has revealed that the NAD+ declines associated with aging contributes to an impairment of immune cells, its role in mast cell function, especially in response to an anaphylactic condition, has remained unexplored. We tested whether the restoration of cellular NAD+ concentration by the supplementation of NAD+ boosting molecules prevented mast cell degranulation and anaphylactic responses.Methods: Bone marrow derived mast cells (BMMCs) and human cord blood derived mast cells were treated with NAD+ precursors nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR), and FcεRI downstream signaling was assessed. Animal models of passive systemic anaphylaxis (PSA) and passive cutaneous anaphylaxis (PCA) were used to investigate the effects of NAD+ precursors in the anaphylactic responses of mice.Results: Treatment of murine BMMCs and human cord blood derived mast cells with NAD+ precursors repressed intracellular signaling downstream of FcεRI, as well as the release of inflammatory cytokines and lipid mediators. The intraperitoneal administration of NMN or NR also markedly attenuated IgE-mediated anaphylactic responses in mouse models of PSA and PCA. These beneficial effects of NAD+ precursors, however, were attenuated in mast cell-specific Sirt6 knockout mice, indicating a Sirt6 dependency for their action.Conclusion: NAD+ precursors may serve as an effective therapeutic strategy that limits mast cell-mediated anaphylactic responses.

Macrophage COX2 Mediates Efferocytosis, Resolution Reprogramming, and Intestinal Epithelial Repair.

Background and AimsPhagocytosis (efferocytosis) of apoptotic neutrophils by macrophages anchors the resolution of intestinal inflammation. Efferocytosis prevents secondary necrosis and inhibits further inflammation, and also reprograms macrophages to facilitate tissue repair and promote resolution function. Macrophage efferocytosis and efferocytosis-dependent reprogramming are implicated in the pathogenesis of inflammatory bowel disease. We previously reported that absence of macrophage cyclooxygenase 2 (COX2) exacerbates inflammatory bowel disease–like intestinal inflammation. To elucidate the underlying pathogenic mechanism, we investigated here whether COX2 mediates macrophage efferocytosis and efferocytosis-dependent reprogramming, including intestinal epithelial repair capacity.MethodsUsing apoptotic neutrophils and synthetic apoptotic targets, we determined the effects of macrophage specific Cox2 knockout and pharmacological COX2 inhibition on the efferocytosis capacity of mouse primary macrophages. COX2-mediated efferocytosis-dependent eicosanoid lipidomics was determined by liquid chromatography tandem mass spectrometry. Small intestinal epithelial organoids were employed to assay the effects of COX2 on efferocytosis-dependent intestinal epithelial repair.ResultsLoss of COX2 impaired efferocytosis in mouse primary macrophages, in part, by affecting the binding capacity of macrophages for apoptotic cells. This effect was comparable to that of high-dose lipopolysaccharide and was accompanied by both dysregulation of macrophage polarization and the inhibited expression of genes involved in apoptotic cell binding. COX2 modulated the production of efferocytosis-dependent lipid inflammatory mediators that include the eicosanoids prostaglandin I2, prostaglandin E2, lipoxin A4, and 15d-PGJ2; and further affected secondary efferocytosis. Finally, macrophage efferocytosis induced, in a macrophage COX2–dependent manner, a tissue restitution and repair phenotype in intestinal epithelial organoids.ConclusionsMacrophage COX2 potentiates efferocytosis capacity and efferocytosis-dependent reprogramming, facilitating macrophage intestinal epithelial repair capacity.

Group 2 innate lymphoid cells (ILC2s) are important in typical type 2 immune-mediated diseases and an essential therapeutic target.

The prevalence rate of allergic diseases, such as asthma, atopic rhinitis (AR), and atopic dermatitis (AD), has been significantly increasing over the years because of environmental changes. Type 2 immunity is mediated by allergic inflammation initiated by an innate immune response. This response is orchestrated by type 2 cytokines (interleukin [IL]-4, IL-5, IL-9, and IL-13) together with other cells. The dendritic cell [DC]-T helper 2 (Th2) cell axis is the conventional type 2 immune pathway, and is currently known as the group 2 innate lymphoid cell (ILC2)-DC-Th2 axis that mediates type 2 inflammation. ILC2s strongly mediate type 2 inflammation in allergic diseases. ILC2s are activated by epithelial cell-derived cytokines, such as IL-25 and IL-33, and thymic stromal lymphopoietin. Additionally, ILC2s are activated by mast cell lipid inflammatory mediators, such as cysteinyl leukotrienes and prostaglandin D2. ILC2s produce a large amount of type 2 cytokines. The important role of ILC2s in the pathogenesis of type 2-mediated disease has resulted in ILC2-derived cytokines being a target for therapeutic development. In this review, we discuss type 2 immunity, mainly the ILC2-DC-Th2 axis, and other immune cells, the dominant role of ILC2s in asthma, AR, and AD, and therapeutic targets against type 2 cytokines.

Dehydrogenase reductase 9 (SDR9C4) and related homologs recognize a broad spectrum of lipid mediator oxylipins as substrates

Bioactive oxylipins play multiple roles during inflammation and in the immune response, with termination of their actions partly dependent on the activity of yet-to-be characterized dehydrogenases. Here, we report that human microsomal dehydrogenase reductase 9 (DHRS9, also known as SDR9C4 of the short-chain dehydrogenase/reductase (SDR) superfamily) exhibits a robust oxidative activity toward oxylipins with hydroxyl groups located at carbons C9 and C13 of octadecanoids, C12 and C15 carbons of eicosanoids, and C14 carbon of docosanoids. DHRS9/SDR9C4 is also active toward lipid inflammatory mediator dihydroxylated Leukotriene B4 and proresolving mediators such as tri-hydroxylated Resolvin D1 and Lipoxin A4, although notably, with lack of activity on the 15-hydroxyl of prostaglandins. We also found that the SDR enzymes phylogenetically related to DHRS9, i.e., human SDR9C8 (or retinol dehydrogenase 16), the rat SDR9C family member known as retinol dehydrogenase 7, and the mouse ortholog of human DHRS9 display similar activity toward oxylipin substrates. Mice deficient in DHRS9 protein are viable, fertile, and display no apparent phenotype under normal conditions. However, the oxidative activity of microsomal membranes from the skin, lung, and trachea of Dhrs9−/− mice toward 1 μM Leukotriene B4 is 1.7- to 6-fold lower than that of microsomes from wild-type littermates. In addition, the oxidative activity toward 1 μM Resolvin D1 is reduced by about 2.5-fold with DHRS9-null microsomes from the skin and trachea. These results strongly suggest that DHRS9 might play an important role in the metabolism of a wide range of bioactive oxylipins in vivo.