Explore the vast range of titles available.

Endocannabinoids (eCBs) are lipid-based retrograde messengers with a relatively short half-life that are produced endogenously and, upon binding to the primary cannabinoid receptors CB1/2, mediate multiple mechanisms of intercellular communication within the body. Endocannabinoid signaling is implicated in brain development, memory formation, learning, mood, anxiety, depression, feeding behavior, analgesia, and drug addiction. It is now recognized that the endocannabinoid system mediates not only neuronal communications but also governs the crosstalk between neurons, glia, and immune cells, and thus represents an important player within the neuroimmune interface. Generation of primary endocannabinoids is accompanied by the production of their congeners, the N-acylethanolamines (NAEs), which together with N-acylneurotransmitters, lipoamino acids and primary fatty acid amides comprise expanded endocannabinoid/endovanilloid signaling systems. Most of these compounds do not bind CB1/2, but signal via several other pathways involving the transient receptor potential cation channel subfamily V member 1 (TRPV1), peroxisome proliferator-activated receptor (PPAR)-α and non-cannabinoid G-protein coupled receptors (GPRs) to mediate anti-inflammatory, immunomodulatory and neuroprotective activities. In vivo generation of the cannabinoid compounds is triggered by physiological and pathological stimuli and, specifically in the brain, mediates fine regulation of synaptic strength, neuroprotection, and resolution of neuroinflammation. Here, we review the role of the endocannabinoid system in intrinsic neuroprotective mechanisms and its therapeutic potential for the treatment of neuroinflammation and associated synaptopathy.

Double sensitization (DS) to bee and vespid venom is frequently observed in the diagnosis of hymenoptera venom allergy, but clinically relevant DS is rare. Therefore it is sophisticated to choose the relevant venom for specific immunotherapy and overtreatment with both venoms may occur. We aimed to compare currently available routine diagnostic tests as well as experimental tests to identify the most accurate diagnostic tool. 117 patients with a history of a bee or vespid allergy were included in the study. Initially, IgE determination by the ImmunoCAP, by the Immulite, and by the ADVIA Centaur, as well as the intradermal test (IDT) and the basophil activation test (BAT) were performed. In 72 CAP double positive patients, individual IgE patterns were determined by western blot inhibition and component resolved diagnosis (CRD) with rApi m 1, nVes v 1, and nVes v 5. Among 117 patients, DS was observed in 63.7% by the Immulite, in 61.5% by the CAP, in 47.9% by the IDT, in 20.5% by the ADVIA, and in 17.1% by the BAT. In CAP double positive patients, western blot inhibition revealed CCD-based DS in 50.8%, and the CRD showed 41.7% of patients with true DS. Generally, agreement between the tests was only fair and inconsistent results were common. BAT, CRD, and ADVIA showed a low rate of DS. However, the rate of DS is higher than expected by personal history, indicating that the matter of clinical relevance is still not solved even by novel tests. Furthermore, the lack of agreement between these tests makes it difficult to distinguish between bee and vespid venom allergy. At present, no routinely employed test can be regarded as gold standard to find the clinically relevant sensitization.

Of the known prostanoid receptors, human eosinophils express the prostaglandin D (PGD ) receptors DP1 [also D-type prostanoid (DP)] and DP2 (also chemoattractant receptor homologous molecule, expressed on Th2 cells), the prostaglandin E receptors EP2 and EP4, and the prostacyclin (PGI ) receptor IP. Prostanoids can bind to either one or multiple receptors, characteristically have a short half-life , and are quickly degraded into metabolites with altered affinity and specificity for a given receptor subtype. Prostanoid receptors signal mainly through G proteins and naturally activate signal transduction pathways according to the G protein subtype that they preferentially interact with. This can lead to the activation of sometimes opposing signaling pathways. In addition, prostanoid signaling is often cell-type specific and also the combination of expressed receptors can influence the outcome of the prostanoid impulse. Accordingly, it is assumed that eosinophils and their (patho-)physiological functions are governed by a sensitive prostanoid signaling network. In this review, we specifically focus on the functions of PGD , PGE , and PGI and their receptors on eosinophils. We discuss their significance in allergic and non-allergic diseases and summarize potential targets for drug intervention.

Macrophage dysfunction is a common feature of inflammatory disorders such as asthma, which is characterized by a strong circadian rhythm. We monitored the protein expression pattern of the molecular circadian clock in human peripheral blood monocytes from healthy, allergic, and asthmatic donors during a whole day. Monocytes cultured of these donors allowed us to examine circadian protein expression in human monocyte-derived macrophages, M1- and M2- polarized macrophages. In monocytes, particularly from allergic asthmatics, the oscillating expression of circadian proteins CLOCK, BMAL, REV ERBs, and RORs was significantly altered. Similar changes in BMAL1 were observed in polarized macrophages from allergic donors and in tissue-resident macrophages from activated precision cut lung slices. We confirmed clock modulating, anti-inflammatory, and lung-protective properties of the inverse ROR agonist SR1001 by reduced secretion of macrophage inflammatory protein and increase in phagocytosis. Using a house dust mite model, we verified the therapeutic effect of SR1001 . Overall, our data suggest an interaction between the molecular circadian clock and monocytes/macrophages effector function in inflammatory lung diseases. The use of SR1001 leads to inflammatory resolution and and represents a promising clock-based therapeutic approach for chronic pulmonary diseases such as asthma.

Acute respiratory inflammation, most commonly resulting from bacterial or viral infection, is one of the leading causes of death and disability worldwide. The inflammatory lipid mediator prostaglandin D2 (PGD2) and its rate-limiting enzyme, hematopoietic PGD synthase (hPGDS), are well-known drivers of allergic pulmonary inflammation. Here, we sought to investigate the source and role of hPGDS-derived PGD2 in acute pulmonary inflammation. Murine bronchoalveolar monocytes/macrophages from LPS- but not OVA-induced lung inflammation released significant amounts of PGD2. Accordingly, human monocyte-derived macrophages expressed high basal levels of hPGDS and released significant levels of PGD2 after LPS/IFN-γ, but not IL-4 stimulation. Human peripheral blood monocytes secreted significantly more PGD2 than monocyte-derived macrophages. Using human precision-cut lung slices (PCLS), we observed that LPS/IFN-γ but not IL-4/IL-13 drive PGD2 production in the lung. HPGDS inhibition prevented LPS-induced PGD2 release by human monocyte-derived macrophages and PCLS. As a result of hPGDS inhibition, less TNF-α, IL-6 and IL-10 could be determined in PCLS-conditioned medium. Collectively, this dataset reflects the time-dependent release of PGD2 by human phagocytes, highlights the importance of monocytes and macrophages as PGD2 sources and suggests that hPGDS inhibition might be a potential therapeutic option for acute, non-allergic lung inflammation.

Eosinophilic esophagitis (EoE) is a chronic, inflammatory, antigen-driven disease of the esophagus. Tissue EoE pathology has previously been extensively characterized by novel transcriptomics and proteomic platforms, however the majority of surface marker determination and screening has been performed in blood due to mucosal tissue size limitations. While eosinophils, CD4 T cells, mast cells and natural killer (NK) T cells were previously investigated in the context of EoE, an accurate picture of the composition of peripheral blood mononuclear cells (PBMC) and their activation is missing. In this study, we aimed to comprehensively analyze the composition of peripheral blood mononuclear cells and their activation using surface marker measurements with multicolor flow cytometry simultaneously in both blood and mucosal tissue of patients with active EoE, inactive EoE, patients with gastroesophageal reflux disease (GERD) and controls. Moreover, we set out to validate our data in co-cultures of PBMC with human primary esophageal epithelial cells and in a novel inducible mouse model of eosinophilic esophagitis, characterized by extensive IL-33 secretion in the esophagus. Our results indicate that specific PBMC populations are enriched, and that they alter their surface expression of activation markers in mucosal tissue of active EoE. In particular, we observed upregulation of the immunomodulatory molecule CD38 on CD4 T cells and on myeloid cells in biopsies of active EoE. Moreover, we observed significant upregulation of PD-1 on CD4 and myeloid cells, which was even more prominent after corticosteroid treatment. With co-culture experiments we could demonstrate that direct cell contact is needed for PD-1 upregulation on CD4 T cells. Finally, we validated our findings of PD-1 and CD38 upregulation in an inducible mouse model of EoE. Herein we show significant alterations in the PBMC activation profile of patients with active EoE in comparison to inactive EoE, GERD and controls, which could have potential implications for treatment. To our knowledge, this study is the first of its kind expanding the multi-color flow cytometry approach in different patient groups using and translational models.

BackgroundThe prostaglandin D2 receptor DP2 has been implicated in eosinophil infiltration and the development of eosinophilic esophagitis (EoE).Aims and MethodsIn this study, we investigated an involvement of PGE2 (EP1–EP4) and PGD2 (DP1) receptors in EoE by measuring their expression in peripheral blood eosinophils and esophageal mucosal biopsies of EoE patients and by performing migration and adhesion assays with eosinophils from healthy donors.ResultsExpression of EP2 and EP4, but not EP1 and EP3, was decreased in blood eosinophils of patients with EoE vs. control subjects. Adhesion of eosinophils to esophageal epithelial cells was decreased by EP2 receptor agonist butaprost and EP4 agonist ONO-AE1-329, whereas DP1 agonist BW245C increased adhesion. In chemotaxis assays with supernatant from human esophageal epithelial cells, only ONO-AE1-329 but not butaprost or BW245C inhibited the migration of eosinophils. Expression of EP and DP receptors in epithelial cells and eosinophils was detected in sections of esophageal biopsies from EoE patients by immunohistochemistry. qPCR of biopsies from EoE patients revealed that gene expression of EP4 and DP1 was the highest among PGE2 and PGD2 receptors. Esophageal epithelial cells in culture showed high gene expression for EP2 and EP4. Activation of EP2 and EP4 receptors decreased barrier integrity of esophageal epithelial cells in impedance assays.ConclusionsActivation of EP2 and EP4 receptors may inhibit eosinophil recruitment to the esophageal mucosa. However, their activation could negatively affect esophageal barrier integrity suggesting that eosinophilic rather than epithelial EP2 and EP4 have a protective role in EoE.

Accumulation of eosinophils in tissue is a hallmark of allergic inflammation. Here we observed that a selective agonist of the PGE 2 receptor EP4, ONO AE1-329, potently attenuated the chemotaxis of human peripheral blood eosinophils, upregulation of the adhesion molecule CD11b and the production of reactive oxygen species. These effects were accompanied by the inhibition of cytoskeletal rearrangement and Ca 2+ mobilization. The involvement of the EP4 receptor was substantiated by a selective EP4 antagonist, which reversed the inhibitory effects of PGE 2 and the EP4 agonist. Selective kinase inhibitors revealed that the inhibitory effect of EP4 stimulation on eosinophil migration depended upon activation of PI 3-kinase and PKC, but not cAMP. Finally, we found that EP4 receptors are expressed by human eosinophils, and are also present on infiltrating leukocytes in inflamed human nasal mucosa. These data indicate that EP4 agonists might be a novel therapeutic option in eosinophilic diseases.

Crohn's disease (CD) is a chronic inflammatory disorder primarily affecting the gastrointestinal tract. Leukocyte recruitment, M1 macrophage polarization and associated metabolic reprogramming are hallmarks of its pathomechanism. Here, we tested TE-11, a potent MIF tautomerase inhibitor (IC = 5.63 μmol/dm ) in experimental Crohn's disease in male mice, in leukocyte recruitment and in inflammatory M1 macrophage activation. 2,4,6-trinitrobenzenesulfonic acid-(TNBS)-induced colitis was utilized as a CD-model in male mice. We performed macroscopic scoring and cytokine measurements. We also analyzed MIF-induced leukocyte migration and evaluated apoptosis. LPS+IFN-γ-induced RAW264.7 cells were applied as a M1 macrophage model. We performed qPCR, ROS and nitrite determinations, ELISA measurements, mitochondrial oxygen consumption rate and extracellular acidification rate determinations. TE-11 improved mucosal damage, reduced inflammation score and concentration of IL-1β and IL-6 in the colon. It inhibited MIF-induced human blood eosinophil and neutrophil migration and counteracted the anti-apoptotic effect of MIF. In macrophages, MIF inhibition prevented M1 polarization by downregulating HIF-1α gene expression in LPS+IFN-γ-activated cells. Additionally, the molecule reduced mRNA transcription and protein expression of chemokine CCL-2 and cytokine IL-6 while further increasing SOD2 gene transcription and decreased ROS and nitrite production in macrophages. During inflammatory metabolic reprogramming, TE-11 prevented LPS+IFN-γ-induced metabolic shift from OXPHOS to glycolysis. Similarly to anti-inflammatory M2 cells, TE-11 improved mitochondrial energy production by increasing basal respiration, ATP production, coupling efficiency, maximal respiration and spare respiratory capacity. Comprehensively, TE-11, a MIF tautomerase inhibitor ameliorates CD-like colitis, reduces MIF-induced eosinophil and neutrophil migration and prevents M1 polarization and associated metabolic reprogramming; therefore, it may prove beneficial as a potential drug candidate regarding CD therapy.

Accumulation of type 2 T helper (Th2) lymphocytes and eosinophils is a hallmark of bronchial asthma and other allergic diseases, and it is believed that these cells play a crucial pathogenic role in allergic inflammation. Thus, Th2 cells and eosinophils are currently considered a major therapeutic target in allergic diseases and asthma. However, drugs that selectively target the accumulation and activation of Th2 cells and eosinophils in tissues are unavailable so far. Prostaglandin (PG)D 2 is a key mediator in various inflammatory diseases including allergy and asthma. It is generated by activated mast cells after allergen exposure and subsequently orchestrates the recruitment of inflammatory cells to the tissue. PGD 2 induces the chemotaxis of Th2 cells, basophils and eosinophils, stimulates cytokine release from these cells and prolongs their survival, and might hence indirectly promote IgE production. PGD 2 mediates its biologic functions via 2 distinct G protein-coupled receptors, D-type prostanoid receptor (DP), and the chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2). DP and CRTH2 receptors are currently being considered as highly promising therapeutic targets for combating allergic diseases and asthma. Here, we revisit the roles of PGD 2 receptors in the regulation of eosinophil and Th2 cell function and the efforts towards developing candidate compounds for clinical evaluation.