eosinophils

Theophylline monohydrate (Quibron) appears to inhibit phosphodiesterase and prostaglandin production, regulate calcium flux and intracellular calcium distribution, and antagonize adenosine. Theophylline monohydrate is a natural alkaloid derivative of xanthine isolated from the plants Camellia sinensis and Coffea arabica. Physiologically, this agent relaxes the bronchial smooth muscle, produces vasodilation (except in cerebral vessels), stimulates the CNS, stimulates the cardiac muscle, induces diuresis, and increases gastric acid secretion; it may also suppress inflammation and improve contractility of the diaphragm.

Theophylline (1,3-Dimethylxanthine) is a methyl xanthine derivative from tea with diuretic, smooth muscle relaxant, bronchial dilation, cardiac, and central nervous system stimulant activities. It inhibits the 3', 5'-cyclic nucleotide phosphodiesterase that degrades cyclic AMP, thus potentiating the actions of agents that act through adenylyl cyclases and cyclic AMP.

CGP 20376 is a benzothiazole compound, an anthelmintic, with dual dose-dependent modulation of in vitro effects on the respiratory burst of eosinophils and antifibrillatory properties.

JNJ 10191584 maleate (VUF6002 maleate) is an orally active and selective antagonist of H4 receptor (Ki = 26 nM). JNJ 10191584 maleate inhibits chemotaxis of eosinophils and mast cells (IC50 = 530 nM and 138 nM).

Secretoneurin, rat acetate is a 33-amino acid polypeptide generated by proteolytic processing of secretogranin II (SgII). Secretoneurin, rat acetate induces dopamine release in the rat striatum in vivo and in vitro, and it exerts a very strong chemotactic effect on monocytes and eosinophils but not on granulocytes.

5-OxoETE is a polyunsaturated keto acid formed by the oxidation of 5-HETE in human neutrophils by a specific dehydrogenase.[1] It stimulates cytosolic calcium levels in neutrophils with an EC50 value of 2 nM.[2] 5-OxoETE selectively stimulates the migration and degranulation of eosinophils and activates the MAPK pathway in stimulated neutrophils via a specific G protein-coupled receptor.[3],[4],[5],[6]

Etiprednol dicloacetate (BNP-166) is a corticosteroid with anti-inflammatory activity.Etiprednol dicloacetate inhibits the accumulation of eosinophils and can be used in the study of inflammatory airway diseases such as asthma and in the treatment of Crohn's disease.

Flunisolide hemihydrate is a corticosteroid, an orally active Glucocorticoid receptor activator with anti-inflammatory effects. flunisolide hemihydrate induces apoptosis in eosinophils and can be used in asthma or rhinitis, inflammatory diseases. Can be used in studies related to asthma or rhinitis, inflammation.

Enoximone is a selective inhibitor of phosphodiesterase III (PDE3), with treatment of congestive heart failure.

YM-90709 is a new-type antagonist inhibiting the binding of interleukin-5 to the interleukin-5 receptor.

SB297006 is an antagonist of C-C chemokine receptor 3 (CCR3; IC50 = 39 nM), which normally is activated by eotaxin, eotaxin-3, MCP-3, MCP-4, RANTES, and MIP-1δ. It is at least 250-fold selective for CCR3 over a panel of other chemokine receptors. SB 297006 blocks CCR3-mediated calcium mobilization induced by eotaxin, eotaxin-2, and MCP-4 in transfected cells. It suppresses antigen-induced accumulation of Th2 lymphocytes and eosinophils in lungs of mice when delivered subcutaneously (100 mg/kg).

RWJ 58643 is a reversible beta-tryptase and trypsin inhibitor. Low-dose RWJ-58643 (100 microg) and budesonide (200 microg) significantly reduced symptoms, eosinophils and levels of IL-5 following NAC. However, higher doses of RWJ-58643 (300 and 600 microg) caused a late eosinophilia and preceding increases in IL-5 compared with placebo.

Imetit dihydrobromide is a high affinity and effective agonist of histamine H3 and H4 receptors (Ki: 0.3 and 2.7 nM). Imetit mimics the histamine effect in triggering a shape change in eosinophils (EC50: 25 nM).

14,15-Leukotriene D4 (14,15-LTD4) is a member of an alternate class of LTs synthesized by a pathway involving the dual actions of 15- and 12-lipoxygenases (15- and 12-LOs) on arachidonic acid via 15-HpETE and 14,15-LTA4 intermediates. 14,15-LTD4 is classified as an eoxin (EXD4), because it is formed mostly by eosinophils. However, mast cells and nasal polyps can synthesize 14,15-LTD4 as well. Little is known about the physiological actions of 14,15-LTD4. It has weak contractile activity on both guinea pig ileum and pulmonary parenchyma in contrast to the effects of 5-LO-derived LTs. However, in an in vitro permeability assay, 14,15-LTD4 can increase vascular permeability of human endothelial cell monolayers, with similar potency to that of 5-LO-derived LTs, resulting in plasma leakage, a hallmark of inflammation.

PAR2 (1-6) amide is a synthetic peptide agonist of proteinase-activated receptor 2 (PAR2) that corresponds to residues 1-6 of the amino terminal tethered ligand sequence of human PAR2 and residues 37-42 of the full-length sequence.1It binds to NCTC 2544 cells expressing human PAR2 (Ki= 9.64 μM in a radioligand binding assay) and induces calcium mobilization in the same cells (EC50= 0.075 μM).2PAR2 (1-6) amide (100 μM) reduces colony formation of A549 lung cancer cells.1It induces superoxide production and degranulation in isolated human eosinophils when used at a concentration of 500 μM.3PAR2 (1-6) amide (5 μmol/kg) induces tear secretion in rats when used in combination with amastatin .4 1.Bohm, S.K., Kong, W., Bromme, D., et al.Molecular cloning, expression and potential functions of the human proteinase-activated receptor-2Biochem. J.314(Pt 3)1009-1016(1996) 2.Kanke, T., Ishiwata, H., Kabeya, M., et al.Binding of a highly potent protease-activated receptor-2 (PAR2) activating peptide, [3H]2-furoyl-LIGRL-NH2, to human PAR2Br. J. Pharmacol.145(2)255-263(2005) 3.Miike, S., McWilliam, A.S., and Kita, H.Trypsin induces activation and inflammatory mediator release from human eosinophils through protease-activated receptor-2J. Immunol.167(11)6615-6622(2001) 4.Nishikawa, H., Kawai, K., Tanaka, M., et al.Protease-activated receptor-2 (PAR-2)-related peptides induce tear secretion in rats: Involvement of PAR-2 and non-PAR-2 mechanismsJ. Pharmacol. Exp. Ther.312(2)324-331(2005)

3-Bromotyrosine, a product of protein oxidation, is generated after eosinophil activation during allergic responses. It serves as a biomarker for eosinophil peroxidase-induced protein oxidation both in vitro and in vivo. Beyond its association with eosinophils, 3-bromotyrosine levels are significantly elevated in peritoneal exudate from K. pneumoniae-infected mice, indicating a fivefold increase compared to uninfected controls, which implies that neutrophils may release increased levels of oxidized products during inflammation. Furthermore, in humans, allergen-challenged lung samples from patients with allergen-induced asthma show a tenfold increase in 3-bromotyrosine, highlighting its potential as a marker for oxidative stress in allergic conditions.

Leukotriene C4 (14,15-LTC4) is an inflammatory mediator synthesized from arachidonic acid through the actions of 15- and 12-lipoxygenases (LOs), involving intermediates such as 15-HpETE and 14,15-LTA4. Unlike the majority of leukotrienes formed via the 5-LO pathway, 14,15-LTC4 is an eoxin predominantly produced by eosinophils, although mast cells and nasal polyps can also synthesize it. While its physiological roles are not well understood, 14,15-LTC4 exhibits limited contractile activity on guinea pig ileum and pulmonary parenchyma. However, it can increase vascular permeability in human endothelial cell monolayers in vitro with potency comparable to 5-LO-derived leukotrienes, contributing to plasma leakage characteristic of inflammation.

15-deoxy-Δ12,14-Prostaglandin D2 (15-deoxy-Δ12,14-PGD2) is a PGD2 metabolite functioning as an agonist for the PGD2 receptor 2 (DP2), with a binding affinity (Ki) of 50 nM for the mouse DP2 receptor expressed in HEK293 cell membranes. It activates eosinophils with an EC50 of 8 nM and enhances the recruitment of steroid receptor coactivator-1 (SRC-1) to peroxisome proliferator-activated receptor γ (PPARγ), initiating PPARγ-mediated transcription at 5 µM concentration. Furthermore, it exhibits cytotoxicity towards L1210 murine leukemia cells with an IC50 of 0.3 µg/ml and displays weaker inhibition of ADP-induced platelet aggregation than PGD2, with an IC50 of 320 ng/ml.

15(R)-Prostaglandin D2 functions as a DP(2) receptor (Prostaglandin Receptor) agonist with potential roles in prostatic hormone signaling and exhibits anti-inflammatory properties. It enhances actin polymerization in human eosinophils and elevates cAMP levels in platelets [1].

Benralizumab (MEDI-563) is a monoclonal antibody targeting the interleukin-5 receptor alpha (IL-5Rα). It enhances antibody-dependent cell-mediated cytotoxicity, leading to a rapid depletion of eosinophils. Benralizumab is used for severe eosinophilic asthma and can be employed to prevent exacerbations of chronic obstructive pulmonary disease.

5(S),15(S)-DiHETE is synthesized by 15-LO from 5(S)-HETE. It potentiates the degranulation of human PMNL in response to PAF, but not fMLP, calcium ionophore A23187, or LTB4. 5(S),15(S)-DiHETE is chemotactic for eosinophils with an ED50 value of 0.3 μM.

9(S),12(S),13(S)-TriHOME is a linoleic acid-derived oxylipin that has diverse biological activities.1,2,3,4It has been found in various plants and is produced in human eosinophils in a 15-lipoxygenase-dependent, soluble epoxide hydrolase-independent manner.1,59(S),12(S)13(S)-TriHOME inhibits antigen-induced β-hexosaminidase release from RBL-2H3 mast cells (IC50= 28.7 μg ml).2It inhibits LPS-induced nitric oxide (NO) production in BV-2 microglia (IC50= 40.95 μM).3In vivo, 9(S),12(S),13(S)-TriHOME (1 g animal) enhances the antiviral IgA and IgG antibody responses induced by a nasal influenza hemagglutinin (HA) vaccine by 5.2- and 2-fold, respectively, in mice.4 1.Hamberg, M., and Hamberg, G.Peroxygenase-catalyzed fatty acid epoxidation in cereal seeds: Sequential oxidation of linoleic acid into 9(S),12(S),13(S)-trihydroxy-10(E)-octadecenoic acidPlant Physiol.110(3)807-815(1996) 2.Hong, S.S., and Oh, J.S.Inhibitors of antigen-induced degranulation of RBL-2H3 cells isolated from wheat branJ. Korean Soc. Appl. Biol. Chem.5569-74(2012) 3.Kim, C.S., Kwon, O.W., Kim, S.Y., et al.Five new oxylipins from Chaenomeles sinensisLipids49(11)1151-1159(2014) 4.Shirahata, T., Sunazuka, T., Yoshida, K., et al.Total synthesis, elucidation of absolute stereochemistry, and adjuvant activity of trihydroxy fatty acidsTetrahedron62(40)9483-9496(2006) 5.Fuchs, D., Tang, X., Johnsson, A.-K., et al.Eosinophils synthesize trihydroxyoctadecenoic acids (TriHOMEs) via a 15-lipoxygenase dependent processBiochim. Biophys. Acta Mol. Cell Biol. Lipids1865(4)158611(2020)

BLX3887 is an inhibitor of 15-lipoxygenase type 1 (15-LO-1; IC50 = 32 nM in a cell-free enzyme assay).1 It is selective for 15-LO-1 over 15-LO-2, which it does not inhibit, 5-LO (IC50 = 472 nM), and 12-LO (IC50 = 3,310 nM). BLX3887 inhibits the production of 15-LO metabolites selectively in eosinophils over neutrophils when used at a concentration of 10 μM. It also inhibits endocytosis in, and the migration of, isolated human peripheral blood mononuclear cell-derived dendritic cells in vitro. |1. Archambault, A.-S., Turcotte, C., Martin, C., et al. Comparison of eight 15-lipoxygenase (LO) inhibitors on the biosynthesis of 15-LO metabolites by human neutrophils and eosinophils. PLoS One 13(8), e0202424 (2018).

Val-Gly-Ser-Glu (NSC 350591), an ECF-A tetrapeptide, dose-dependently enhances the rosetting of human eosinophils with complement-coated sheep erythrocytes (EAC3b) without affecting neutrophils [1].

11-trans Leukotriene C4 (11-trans LTC4) is a C-11 double bond isomer of LTC4. LTC4 undergoes slow temperature-dependent isomerization to 11-trans LTC4 during storage. 11-trans LTC4 is produced in smaller amounts relative to LTC4 in ionophore-stimulated HMC-1 cells (a human mast cell line) and equine eosinophils, but not in human neutrophils or RBL-1 cells. It is nearly equipotent with LTC4 for contraction of guinea pig parenchymal and ileum. In a radioligand binding assay using guinea pig ileum as a cysteinyl leukotriene receptor preparation, the pKis for LTC4 and 11-trans LTC4 were determined to be 6.42 and 6.58, respectively.

Lirentelimab (AK002), a humanized IgG1 monoclonal antibody, specifically targets sialic acid-binding Ig-like lectin 8 (SIGLEC8). It promotes apoptosis in IL-5-activated eosinophils and suppresses IgE-mediated activation of mast cells. This compound is under investigation for the treatment of eosinophilic gastritis and duodenitis [1].

Leukotrienes (LTs) are a group of acute inflammatory mediators derived from arachidonic acid in leukocytes. The majority of these metabolites are formed through the 5-lipoxygenase (5-LO) pathway. 14,15-LTE4 is a metabolite of 14,15-LTC4 and 14,15-LTD4, an alternate class of LTs synthesized by a pathway involving the dual actions of 15- and 12-LOs on arachidonic acid via 15-HpETE and 14,15-LTA4 intermediates. These metabolites are classified as eoxins because they are formed mostly by eosinophils. Mast cells and nasal polyps can synthesize 14,15-LTC4 as well, however metabolism to 14,15-LTE4 in these cells and tissue has not been documented. 14,15-LTE4 increases vascular permeability of human endothelial cell monolayers with about 10-fold less potency than LTC4, but approximately 100-fold greater potency than histamine.

A1777, a selective 5-lipoxygenase inhibitor, reduces leukocytes proliferation without affecting the eosinophils of mast cells.

The biological effects of prostaglandin D2 (PGD2) are transduced by at least two 7-transmembrane G protein-coupled receptors, designated DP1 and CRTH2/DP2. In humans, CRTH2/DP2 is expressed on Th2 cells, eosinophils, and basophils where it mediates the chemotactic activity of PGD2. CAY10597, as a racemic mixture, is a potent CRTH2/DP2 receptor antagonist that binds to the human receptor with a Ki value of 37 nM. The R enantiomer is slightly more potent exhibiting Ki values of 23 and 22 nM at the human and murine CRTH2/DP2 receptor, respectively. The R enantiomer of CAY10597 inhibits eosinophil chemotaxis induced by 13,14-dihydro-15-keto-prostaglandin D2 with an IC50 value of 40 nM.

Tirzepatide acts as an agonist for both the glucagon-like peptide 1 receptor (GLP-1R) and G protein-coupled receptor 119 (GPR119), effectively inducing cAMP production in HEK293 cells that express either human GLP-1R or GPR119, with EC50 values of 6.54 and 1.01 nM, respectively. Additionally, at a concentration of 100 nM, it triggers receptor internalization in these cells. In vivo studies demonstrate that tirzepatide, administered at 10 nmol/kg per day, significantly reduces body weight, food intake, as well as plasma and hepatic triglyceride levels, free fatty acids (FFAs), leptin, and blood glucose in mice with high-fat diet-induced obesity. Furthermore, a dose of 50 nmol/kg every three days prevents an increase in eosinophils and lymphocytes in the bronchoalveolar lavage fluid (BALF) and inhibits bronchoconstriction prompted by methacholine in mice models of both asthma and diabetes, indicating its potential in treating type 2 diabetes mellitus.

Setipiprant (ACT-129968) is an orally available, selective CRTH2 antagonist (IC50: 6.0 nM). CRTH2, a G protein-coupled receptor for prostaglandin (PGD2), mediates key inflammatory responses related to allergy and asthma. PGD2, produced by mast cells, binds to CRTH2 on blood-borne cells, inducing chemotaxis of Th2 cells, basophils, and eosinophils, and stimulating cytokine release.

1,1'-Ethylidene-bis-(L-tryptophan) is a potential impurity in L-tryptophan commercial products, promoting EoL-3 eosinophilic leukemia cell proliferation, enhancing eosinophil cationic protein release from human peripheral blood eosinophils, and boosting IL-5 production in human T cells. At 40 µg/kg, it triggers fascia thickening, mast cell infiltration, inflammation, and fibrosis in mouse superficial adipose and panniculus carnosus tissues, serving as an eosinophilia-myalgia syndrome research model.

Epinastine (WAL801), a potent, selective, and orally-active antihistamine and mast cell stabilizer, functions as a histamine H1 receptor antagonist. It also inhibits IL-8 release from human eosinophils, showcasing antiallergic action [1] [2] [3] [4].

(±)5-HEPE is produced by non-enzymatic oxidation of EPA and contains equal amounts of 5(S)-HEPE and 5(R)-HEPE. The biological activity of (±)5-HEPE is likely mediated by one of the individual isomers, most commonly the 5(S) isomer in mammalian systems. EPA can be metabolized to 5-HEPE in human and bovine neutrophils, and human eosinophils, which is further metabolized to 5-oxoEPE and LTB5. The 5-series metabolites of EPA, including 5-HEPE, 5-oxoEPE, and LTB5, have significantly decreased biological effects compared to the arachidonic acid-derived metabolites.

Timapiprant sodium inhibits mast cell activation of Th2 lymphocytes and eosinophils. Timapiprant sodium is a potent and selective D prostanoid receptor 2 antagonist. Timapiprant sodium potently displaces [3H] PGD2 from human recombinant DP2 (Ki=13 nM), ra

β-Defensin-4 is a peptide with antimicrobial properties that protects the skin and mucosal membranes of the respiratory, genitourinary, and gastrointestinal tracts. It induces migration of monocytes in vitro when used at a concentration of 10 nM but does not affect migration of neutrophils and eosinophils. β-Defensin-4 (30 μg/ml) stimulates gene expression and production of IL-6, IL-10, CXCL10, CCL2, MIP-3α, and RANTES by keratinocytes. It also stimulates calcium mobilization, migration, and proliferation of keratinocytes when used at concentrations of 30, 10, and 40 μg/ml, respectively. β-Defensin-4 induces IL-31 production by human peripheral blood-derived mast cells in vitro when used at a concentration of 10 μg/ml and by rat mast cells in vivo following a 500 ng intradermal dose. It also inhibits growth of E. coli, P. aeruginosa, and S. aureus with lethal concentration (LC) values of 5, 12, and 15 μM, respectively, of S. carnosus (MIC = 4.5 μg/ml), and of C. albicans with a minimum fungicidal concentration (MFC) value of 7.5 μM.