jnj-7777120 and Inflammation

The histamine H4 receptor is expressed preferentially on immune cells, indicating a possible role of the H4 receptor in inflammation. Studies of inflammation in several animal models point to a pro-inflammatory function of the H4 receptor. However, studies on experimental murine bronchial asthma yielded conflicting results, a fact which is neglected in most H4 receptor publications. Therefore, the present review critically analyzes available data on the role of the H4 receptor in the murine bronchial asthma model.

Topics: Animals; Asthma; Disease Models, Animal; Histamine; Humans; Indoles; Inflammation; Mice; Piperazines; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H3; Receptors, Histamine H4

All 4 known histamine receptors (H(1)R, H(2)R, H(3)R and H(4)R) have been used or proposed as therapeutic targets for varied diseases. This article reviews the recent progress in understanding the function of the recently described histamine receptor H(4)R in a variety of immune responses and the potential therapeutic value of H(4)R antagonists. The H(4)R is expressed primarily on cells involved in inflammation and immune response. It has effects on chemotaxis, as well as cytokine and chemokine production of mast cells, eosinophils, dendritic cells, and T cells. H(4)R antagonists, JNJ 7777120 and JNJ 10191584 (also known as VUF 6002) have been developed with excellent affinity and selectivity towards human and rodent H(4)R. These antagonists also demonstrate efficacy as anti-inflammatory agents in vivo. H(4)R antagonists have shown promising activity in down-regulating immune responses in a range of animal disease models including acute inflammation, hapten-mediated colitis, and allergic airway inflammation. Due to its distribution on immune cells and its proven role in inflammatory functions, the H(4)R appears to be a therapeutic target for the treatment of a variety of immune disorders.

Topics: Animals; Anti-Inflammatory Agents; Benzimidazoles; Chemotaxis; Cytokines; Down-Regulation; Drug Delivery Systems; Gene Expression Regulation; Humans; Immune System Diseases; Indoles; Inflammation; Piperazines; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H4

This study focuses on the design, synthesis, molecular modeling and biological evaluation of a novel group of alkyl-1,3,5-triazinyl-methylpiperazines. New compounds were synthesized and their affinities for human histamine H

Topics: Analgesics; Animals; Carrageenan; Dose-Response Relationship, Drug; Formaldehyde; Humans; Inflammation; Ligands; Mice; Molecular Structure; Rats; Receptors, Histamine H4; Structure-Activity Relationship; Triazines

The activation of microglial cells is presumed to play a key role in the pathogenesis of Parkinson's disease (PD). The activity of microglia is regulated by the histamine-4 receptor (H

Topics: alpha-Synuclein; Animals; Behavior, Animal; Brain; Corpus Striatum; Disease Models, Animal; Disease Progression; Dopaminergic Neurons; Histamine; Indoles; Inflammation; Male; Microglia; Nerve Degeneration; Parkinson Disease; Parkinsonian Disorders; Piperazines; Rats; Rats, Sprague-Dawley; Receptors, Histamine H4; Rotenone

The histamine H4 receptor (H4R), a member of the G-protein coupled receptor family, has been considered as a potential therapeutic target for treating atopic dermatitis (AD). A large number of H4R antagonists have been disclosed, but no efficient agents controlling both pruritus and inflammation in AD have been developed yet. Here, we have discovered a novel class of orally available H4R antagonists showing strong anti-itching and anti-inflammation activity as well as excellent selectivity against off-targets. A pharmacophore-based virtual screening system constructed in-house successfully identified initial hit compound 9, and the subsequent homology model-guided optimization efficiently led us to discover pyrido[2,3- e]tetrazolo[1,5- a]pyrazine analogue 48 as a novel chemotype of a potent and highly selective H4R antagonist. Importantly, orally administered compound 48 exhibits remarkable efficacy on antipruritus and anti-inflammation with a favorable pharmacokinetic (PK) profile in several mouse models of AD. Thus, these data strongly suggest that our compound 48 is a promising clinical candidate for treatment of AD.

Topics: Animals; Biological Availability; Computer Simulation; Dermatitis, Atopic; Drug Discovery; Drug Evaluation, Preclinical; Female; Histamine Antagonists; Inflammation; Mice; Mice, Inbred BALB C; Mice, Inbred ICR; Models, Molecular; Molecular Conformation; Molecular Docking Simulation; Pruritus; Receptors, Histamine H4; Structure-Activity Relationship

JNJ7777120, a histamine H4 receptor antagonist, was shown to be effective in different experimental settings of allergic inflammation, including contact hypersensitivity. Toll-like receptors (TLRs) are thought to function as a link between innate and adaptive immune responses to various haptens. Here, we studied the suppression of TLR signaling as a possible mechanism by which JNJ7777120 exerts its anti-inflammatory effects against the chemical hapten, fluorescein isothiocyanate (FITC). The potential anti-oxidant effect of JNJ7777120 in this model was also examined. Mice subjected to FITC sensitization and challenge showed significantly elevated plasma immunoglobulin E (IgE) level, ear interleukin-4 (IL-4), tumor necrosis factor-alpha (TNF-α), and thiobarbituric acid reactive substance (TBARS) contents as well as increased myeloid differentiation factor 88 (MyD88) gene expression, nuclear factor-kappa B p65 (NF-κB p65), and phospho-p38 mitogen-activated protein kinase (p-p38 MAPK) protein expression. This was accompanied by enhanced ear myeloperoxidase (MPO) and eosinophil peroxidase (EPO) activities as well as diminished glutathione (GSH) content and superoxide dismutase (SOD) activity. JNJ7777120 treatment perceivably reversed these effects, denoting profound anti-inflammatory and anti-oxidant character of JNJ7777120 which was confirmed by its mitigation of FITC-induced pathological changes in mouse ear. JNJ7777120 additionally enhanced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), providing a novel mechanism by which JNJ7777120 functions as an anti-oxidant in this model. To conclude, JNJ7777120 afforded a remarkable amendment of FITC skin insult by virtue of its anti-inflammatory and anti-oxidant effects; the mechanistic basis of these effects may include modulation of TLR and Nrf2 pathways.

Topics: Animals; Antioxidants; Dermatitis, Contact; Indoles; Inflammation; Mice; NF-E2-Related Factor 2; Oxidative Stress; Piperazines; Receptors, Histamine H4; Signal Transduction; Toll-Like Receptors

Growing evidence associates histamine with arthritis, but its implication in shaping vascular function in chronic inflammation remains largely elusive. This study explored the involvement of vascular histamine in the extra-articular responses in peripheral large blood vessels using a rat model of adjuvant-induced arthritis. Histamine levels were increased in the abdominal aorta and the inferior vena cava of arthritic animals. Contrary to the H1 receptor antagonist dimetindene, histamine induction was observed following administration of the H3 and H4 receptor ligands GSK334429 and JNJ7777120, respectively. In arthritis, prophylactic treatment with GSK334429 partially attenuated the clinical signs and restored basal histamine levels only in the abdominal aorta. This study is the first to implicate the H3 and H4 receptors in a concerted constitutive regulation of basal vascular histamine in the rat large blood vessels and to identify the H3 receptor as a component that may influence arterial histamine during the onset of arthritis.

Topics: Animals; Anti-Inflammatory Agents; Aorta; Arthritis, Experimental; Azepines; Dimethindene; Endothelium; Freund's Adjuvant; Histamine; Histamine H1 Antagonists; Histamine H3 Antagonists; Indoles; Inflammation; Male; Piperazines; Pyridines; Rats; Rats, Wistar; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H3; Receptors, Histamine H4; Vena Cava, Inferior

Histamine 4 receptor (H4R) is a novel target for the pharmacological modulation of histamine-mediated immune signals during inflammatory diseases. The purpose of this study was to assess the effects of the H4R agonist 4-methylhistamine dihydrochloride (4-MeH) and antagonist JNJ7777120 (JNJ) in the inflamed rat knee. Animals were fasted for 18h before a single dose of 4-MeH or JNJ (30mg/kg) was administered intraperitoneally (i.p.), both followed by intra-articular (i.a.) injection of LPS 2h later. Blood and synovial fluid were collected after a short incubation period and TNF-α, NF-κB, and IkB-α levels were measured via flow cytometry. Additionally, we assessed the effects of H4R engagement on the expression of IL-1β, TNF-α, and NF-κB mRNAs and the protein levels of TNF-α, NF-κB, JAK-1, and STAT-3 in the inflamed knee tissue. These results revealed increased TNF-α and NF-κB expression and decreased IkB-α levels in both the LPS alone and 4-MeH treated groups in whole blood and synovial fluid. Further, IL-1β, TNF-α, and NF-κB mRNA levels were significantly increased and western blot analysis confirmed increased expression of TNF-α, NF-κB, JAK-1, and STAT-3 in both LPS and 4-MeH treatment groups. Furthermore, these increases were completely inhibited in the inflamed knee tissue of the JNJ-treated group. Thus, the inhibition of inflammatory mediators and signaling pathways by the H4R antagonist JNJ suggests the anti-arthritic importance of this molecule.

Topics: Animals; Anti-Inflammatory Agents; Enzyme Activation; Female; Gene Expression Regulation; Histamine Agonists; Histamine Antagonists; I-kappa B Proteins; Indoles; Inflammation; Interleukin-1beta; Janus Kinase 1; Knee Joint; Lipopolysaccharides; Methylhistamines; NF-kappa B; NF-KappaB Inhibitor alpha; Piperazines; Rats; Rats, Wistar; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H4; RNA, Messenger; STAT3 Transcription Factor; Tumor Necrosis Factor-alpha

The efficacy of H4R antagonist JNJ7777120 on nasal symptoms, cough, airway resistance (Raw), inflammatory cell count in bronchoalveolar lavage (BAL) and blood in ovalbumin (OVA) induced allergic rhinitis (AR) was studied in guinea pigs. Animals (n=8) were sensitized by i.p. OVA and were repeatedly challenged with nasal OVA to induce rhinitis, seven animals were not sensitized. Animals were pre-treated with JNJ7777120 2.5 and 5mg/kg i.p. 30 min prior OVA. Cough was induced by inhalation of citric acid, Raw was measured in vivo by Pennock's method as baseline, during AR and after JNJ7777120 treatment. Leucocyte count in BAL and blood was analyzed. JNJ7777120 (5mg/kg) significantly suppressed nasal symptoms and the number of coughs. This compound significantly inhibited airway reactivity to histamine, but not methacholine. Pre-treatment with JNJ7777120 5mg/kg did not influence significantly the leucocyte count in BAL and blood except for a significant decrease in monocyte count in blood compared to the control group (p<0.05). We conclude that the antitussive action of JNJ7777120 is peripheral. The primary effect of the compound is anti-inflammatory, and the suppression of cough is a consequence of reduced airway inflammation.

Topics: Airway Resistance; Aluminum Hydroxide; Animals; Bronchoalveolar Lavage Fluid; Citric Acid; Cough; Disease Models, Animal; Dose-Response Relationship, Drug; Guinea Pigs; Indoles; Inflammation; Injections, Intraperitoneal; Nose Diseases; Ovalbumin; Piperazines; Plethysmography; Serotonin Antagonists

The histamine H₄ receptor (H₄R), recently cloned and identified, is a G-protein coupled histamine receptor family expressed in immune cells which plays an important role in inflammation. Recent data evidentiated that H₄R antagonists can decrease airway inflammation and hyperreactivity in animal models of asthma. In the present study we evaluated the effect of the selective H₄R antagonist JNJ7777120 (JNJ) in carrageenan-induced pleurisy, an in vivo model of inflammation, well characterized for cellular and molecular mechanisms. Intra-pleural administration of λ-carrageenan (1% w/v in 0.2 ml sterile saline) determined an intense recruitment of leucocytes in pleural exudates and in lung tissues, activated inducible nitric oxide (NO) synthase and cyclooxygenase-2, thus increasing the generation of harmful autacoids such as NO and pro-inflammatory prostaglandins, PgE₂ and 6-ketoPgF(1α), increased cellular and DNA oxidative stress, measured as malondialdehyde and 8-OH-deoxyguanosine and the local generation of IL-1β and TNF-α. Moreover, the activity of caspase-3, an early marker of apoptosis was also activated by λ-carrageenan injection. The pre-treatment with JNJ (5-10 mg Kg⁻¹ b.wt., given intrapleurally), 60 min before carrageenan markedly reduced all the studied parameters. This study clearly demonstrated that histamine H₄R antagonists have anti-inflammatory effects and could have potential therapeutic application for the treatment of inflammatory diseases.

Topics: Animals; Anti-Inflammatory Agents; Apoptosis; Carrageenan; Caspase 3; Cyclooxygenase 2; Disease Models, Animal; Histamine Antagonists; Indoles; Inflammation; Male; Nitric Oxide Synthase Type II; Piperazines; Pleurisy; Rats; Rats, Wistar; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H4

The histamine 4 receptor (H4R) is expressed primarily on cells involved in inflammation and immune responses. Despite much research into inflammatory diseases, no drugs with favourable safety profiles are yet available for their treatment. The aim of the present study was to determine the potential anti-inflammatory effect of 4-methylhistamine (4-MeH) or JNJ77777120 (JNJ) and to explore the role of H4R in a mouse model of carrageenan (Cg) -induced pleurisy. A single dose of 4-MeH or JNJ (30 mg/kg) was administered intraperitoneally 1 hr before Cg administration. The results illustrate that both the numbers of CD4(+) , CD25(+) , CD4(+)  CD25(+) , GITR(+) , GITR(+)  IL-17A(+) -expressing T cells and the levels of T helper type 1 (Th1)/Th17 cytokines were markedly increased in both the Cg-treated and 4-MeH-treated groups, whereas the cytokines produced by Th2 cells were significantly decreased in the same groups. However, JNJ treatment significantly decreased both the number of T-cell subsets and GITR(+) , GITR(+)  IL-17A(+) -expressing T cells, and the production of Th1/Th17 cytokines. Further, JNJ up-regulated the expression of the Th2 cytokines. RT-PCR analysis revealed an increased expression of interleukin-1β, tumour necrosis factor-α, monocyte chemoattractant protein-1 and intercellular adhesion molecule-1 in the Cg-treated and 4-MeH-treated groups, which was reduced by treatment with JNJ in lung tissues. Moreover, histological examinations revealed anti-inflammatory effects of JNJ, whereas 4-MeH worsened Cg-induced inflammation. In conclusion, the results of the present work clearly indicate that JNJ possesses important anti-inflammatory properties that are increased in 4-MeH-treated mice, suggesting that H4R are involved in pleurisy and that JNJ has an anti-inflammatory effect in associated disease conditions.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Carrageenan; Cytokines; Female; Indoles; Inflammation; Methylhistamines; Mice; Mice, Inbred BALB C; Molecular Targeted Therapy; Piperazines; Pleurisy; Receptors, Histamine; Structure-Activity Relationship

Among the pathogenic mechanisms of asthma, a role for oxidative/nitrosative stress has been well documented. Recent evidence suggests that histamine H₄ receptors play a modulatory role in allergic inflammation. Here we report the effects of compound JNJ 7777120 (JNJ), a selective H4 receptor antagonist, on antigen-induced airway inflammation, paying special attention to its effects on lipocortin-1 (LC-1/annexin-A1), a 37 kDA anti-inflammatory protein that plays a key role in the production of inflammatory mediators.. Ovalbumin (OA)-sensitized guinea pigs placed in a respiratory chamber were challenged with antigen. JNJ (5, 7.5 and 10 mg.kg⁻¹) was given i.p. for 4 days before antigen challenge. Respiratory parameters were recorded. Bronchoalveolar lavage (BAL) fluid was collected and lung specimens taken for further analyses 1 h after antigen challenge. In BAL fluid, levels of LC-1, PGD2 , LTB4 and TNF-α were measured. In lung tissue samples, myeloperoxidase, caspase-3 and Mn-superoxide dismutase activities and 8-hydroxy-2-deoxyguanosine levels were measured.. OA challenge decreased LC-1 levels in BAL fluid, induced cough, dyspnoea and bronchoconstriction and increased PGD2 , LTB4 and TNF-α levels in lung tissue. Treatment with JNJ dose-dependently increased levels of LC-1, reduced respiratory abnormalities and lowered levels of PGD2 , LTB4 and TNF-α in BAL fluid.. Antigen-induced asthma-like reactions in guinea pigs decreased levels of LC-1 and increased TNF-α and eicosanoid production. JNJ pretreatment reduced allergic asthmatic responses and airway inflammation, an effect associated with LC-1 up-regulation.

Topics: Animals; Annexin A1; Antigens; Asthma; Bronchoalveolar Lavage Fluid; Bronchoconstriction; Cough; Dose-Response Relationship, Drug; Guinea Pigs; Histamine Antagonists; Indoles; Inflammation; Lung; Male; Ovalbumin; Piperazines; Tumor Necrosis Factor-alpha; Up-Regulation

The histamine H4 receptor has a primary role in inflammatory functions, making it an attractive target for the treatment of asthma and refractory inflammation. These observations suggested a facilitating action on autoimmune diseases. Here we have assessed the role of H4 receptors in experimental autoimmune encephalomyelitis (EAE) a model of multiple sclerosis (MS).. We induced EAE with myelin oligodendrocyte glycoprotein (MOG35-55 ) in C57BL/6 female mice as a model of MS. The histamine H4 receptor antagonist 5-chloro-2-[(4-methylpiperazin-1-yl)carbonyl]-1H-indole (JNJ7777120) was injected i.p. daily starting at day 10 post-immunization (D10 p.i.). Disease severity was monitored by clinical and histopathological evaluation of inflammatory cells infiltrating into the spinal cord, anti-MOG35-55 antibody production, assay of T-cell proliferation by [(3) H]-thymidine incorporation, mononucleate cell phenotype by flow cytometry, cytokine production by elisa assay and transcription factor quantification of mRNA expression.. Treatment with JNJ7777120 exacerbated EAE, increased inflammation and demyelination in the spinal cord of EAE mice and increased IFN-γ expression in lymph nodes, whereas it suppressed IL-4 and IL-10, and augmented expression of the transcription factors Tbet, FOXP3 and IL-17 mRNA in lymphocytes. JNJ7777120 did not affect proliferation of anti-MOG35-55 T-cells, anti-MOG35-55 antibody production or mononucleate cell phenotype.. H4 receptor blockade was detrimental in EAE. Given the interest in the development of H4 receptor antagonists as anti-inflammatory compounds, it is important to understand the role of H4 receptors in immune diseases to anticipate clinical benefits and also predict possible detrimental effects.

Topics: Animals; Antibody Formation; Cytokines; Disease Models, Animal; Encephalomyelitis, Autoimmune, Experimental; Enzyme-Linked Immunosorbent Assay; Female; Flow Cytometry; Gene Expression Regulation; Histamine Antagonists; Indoles; Inflammation; Mice; Mice, Inbred C57BL; Multiple Sclerosis; Myelin-Oligodendrocyte Glycoprotein; Piperazines; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H4; RNA, Messenger; Severity of Illness Index; T-Lymphocytes

6-Sulpho LacNAc dendritic cells (slanDC) are a major population of human blood DC that are highly pro-inflammatory, as characterized by their outstanding capacity to produce tumour necrosis factor-α and interleukin-12 (IL-12) and to prime antigen-specific T-cell responses. SlanDC were found to be present in inflamed tissue such as atopic dermatitis, where high levels of histamine are also present. As histamine is an important regulator of allergic inflammation we investigated the role of histamine receptors, particularly the most recently identified histamine H(4) receptor (H(4) R), in modulating the pro-inflammatory function of slanDC. The expression of H(4) R was evaluated by real-time PCR and flow cytometry. Cytokine production in response to H(4) R stimulation was assessed by intracellular flow cytometric staining and enzyme-linked immunosorbent assay. We show that slanDC express the H(1) R, H(2) R and H(4) R on mRNA and the H(4) R on protein level. No differences were observed in basal H(4) R expression in patients with atopic dermatitis and psoriasis, but in atopic dermatitis patients the H(4) R was up-regulated by interferon-γ. When stimulated with lipopolysaccharide in the presence of histamine, slanDC produced substantially lower levels of the pro-inflammatory cytokines tumour necrosis factor-α and IL-12, mediated solely via the H(4) R and via the combined action of H(2) R and H(4) R, respectively. In contrast, the production of IL-10 was not affected by histamine receptor activation on slanDC. The slanDC express the H(4) R and its stimulation leads to reduced pro-inflammatory capacity of slanDC. Hence, H(4) R agonists might have therapeutic potential to down-regulate immune reactions, e.g. in allergic inflammatory skin diseases.

Topics: Amino Sugars; Cytokines; Dendritic Cells; Dermatitis, Atopic; Flow Cytometry; Histamine; Humans; Indoles; Inflammation; Interferon-gamma; Lipopolysaccharides; Methylhistamines; Piperazines; Psoriasis; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H4; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

The histamine H(4) receptor (H(4)R) has been implicated in numerous inflammatory functions. Here it is shown that the receptor can mediate cytokine production from mast cells. Histamine and an H(4)R agonist, JNJ 28610244, induced the production of IL-6 in mouse bone marrow (BM)-derived mast cells. This effect was blocked by two different H(4)R antagonists and was not present in H(4)R-deficient cells. In addition, histamine acting via the H(4) R potentiated LPS-induced IL-6 production. Histamine-induced IL-6 production could be blocked by inhibitors of ERK and phosphoinositide 3-kinase γ (PI3Kγ) pathways. Furthermore, it was shown that H(4)R activation can induce phosphorylation of ERK, MEK and AKT. H(4)R activation led to a rapid and transient phosphorylation of these kinases, whereas with LPS the activation occurred at later time points. When both histamine and LPS were added, the phosphorylation was evident at 5 min and persisted for at least 60 min suggesting that changes in the kinetics of kinase activation may be one mechanism driving the signaling interaction between the H(4)R and toll-like receptors. These observations suggest that the H(4)R can synergize with other inflammatory signals to potentiate cytokine production and provides mechanistic information on the role of the H(4)R in inflammation.

Topics: Animals; Bone Marrow; Cells, Cultured; Enzyme Activation; Histamine; Indoles; Inflammation; Interleukin-6; Lipopolysaccharides; Mast Cells; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Mitogen-Activated Protein Kinase 3; Phosphatidylinositol 3-Kinases; Piperazines; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H4; Signal Transduction

Effects of the histamine H(4) receptor antagonist JNJ 7777120 (1-[(5-chloro-1H-indol-2-yl)carbonyl]-4-methylpiperazine) were tested in two models of allergic contact dermatitis. Dermatitis was induced by 2,4-dinitrochlorobenzene and toluene-2,4-diisocyanate, which differ in their Th1-Th2 profile in that way that 2,4-dinitrochlorobenzene is a classical contact allergen with a pronounced Th1-mediated inflammation, while the respiratory chemical allergen toluene-2,4-diisocyanate induces a Th2-dominated inflammation. JNJ 7777120 (15 mg/kg) administered 2 h and 30 min before and 1 h after challenge did not reduce the hapten-induced ear swelling determined 24 h after challenge. This was confirmed by histological evaluation of the ear skin. A repeated administration of the haptens to the rostral part of the back of sensitized animals resulted in a frequent scratching behaviour. An administration of JNJ 7777120 (15 mg/kg) 30 min before challenge reduced this hapten-induced scratching significantly. The H(1) receptor antagonist cetirizine also reduced the scratching bouts in sensitized mice. A combination of H(1) and H(4) receptor antagonists resulted in the strongest inhibition of scratching behaviour associated with allergic dermatitis. These results indicate that H(4) receptor antagonism fails to reduce the allergic inflammatory response but strongly inhibits allergen-induced itch. Thus, a combination of H(4) and H(1) receptor antagonism might be a new strategy to treat pruritus related to allergic diseases like atopic dermatitis.

Topics: Animals; Dermatitis, Atopic; Dose-Response Relationship, Drug; Female; Haptens; Histamine H1 Antagonists; Imidazoles; Indoles; Inflammation; Mice; Mice, Inbred BALB C; Piperazines; Pruritus; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H4; Th2 Cells; Thiourea; Time Factors

Histamine is a well known mediator of allergic skin diseases and, with the discovery of the histamine H(4) receptor, the role of histamine is re-evaluated. There are only limited published data elucidating the role of the histamine H(4) receptor in dogs. Twelve beagles intradermally injected with histamine (0.25 micromol and 2.5 micromol/site) reacted with a classical wheal and flare reaction. None of the dogs showed signs of pruritus. The dogs reacted with a wheal and flare reaction after intradermal injection of histamine H(4) receptor agonist/H(3) receptor antagonist clobenpropit (0.1 micromol) and selective histamine H(4) receptor agonist VUF 8430 (1.5 micromol). Again, no scratching occurred in any of the dogs. The highly selective histamine H(4) receptor antagonist JNJ 7777120 reduced the histamine-induced wheal reaction in nine out of 12 dogs. To determine whether canine mast cells are susceptible to histamine H(4) receptor-mediated reactions, effects of clobenpropit and VUF 8430 were tested in canine mastocytoma cells (C2). Incubation with histamine H(4) receptor agonists (up to 10 micromol/L) induced a distinct calcium(2+) influx. C2 cells also responded with enhanced chemotaxis when stimulated with histamine, VUF 8430 and clobenpropit. Neither VUF 8430, nor clobenpropit (up to 10 micromol/L) led to a modulation of histamine concentration in supernatants of canine mastocytoma cells, whereas mastoparan, used as a positive control, enhanced histamine concentration in supernatants. For treatment of allergic skin diseases in dogs, a combination of H(1)R and H(4)R antagonists might be advantageous.

Topics: Animals; Calcium; Cell Line; Dog Diseases; Dogs; Dose-Response Relationship, Drug; Female; Guanidines; Histamine; Histamine Agonists; Histamine Antagonists; Imidazoles; Indoles; Inflammation; Intercellular Signaling Peptides and Proteins; Male; Mastocytoma; Mice; Mice, Inbred BALB C; Peptides; Piperazines; Receptors, G-Protein-Coupled; Receptors, Histamine; Skin Diseases; Thiourea; Wasp Venoms

The effects of the highly selective histamine H4 receptor antagonists JNJ7777120 and VUF6002 were investigated on the carrageenan-induced inflammation and thermal hyperalgesia in rats. JNJ7777120 (10 and 30 mg/kg, s.c.) and VUF6002 (10 mg/kg, s.c.) significantly reduced paw edema and hyperalgesia provoked by subplantar injection of carrageenan; the effect was evident against the early (2 h) phase of inflammation. An inactive analog of VUF6002, VUF6007 (10 mg/kg, s.c.) slightly aggravated paw edema, while leaving unaltered carrageenan-induced nociception. These findings indicate that histamine H4 receptors participate in the early phase of acute inflammation induced by carrageenan in rats, influencing both edema and thermal hyperalgesia.

Topics: Analgesics; Animals; Anti-Inflammatory Agents; Benzimidazoles; Carrageenan; Disease Models, Animal; Edema; Histamine Antagonists; Hot Temperature; Hyperalgesia; Indoles; Inflammation; Male; Pain Measurement; Piperazines; Rats; Rats, Wistar; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H4; Time Factors

Histamine is an important inflammatory mediator that is released in airways during an asthmatic response. However, current antihistamine drugs are not effective in controlling the disease. The discovery of the histamine H4 receptor (H4R) prompted us to reinvestigate the role of histamine in pulmonary allergic responses. H4R-deficient mice and mice treated with H4R antagonists exhibited decreased allergic lung inflammation, with decreases in infiltrating lung eosinophils and lymphocytes and decreases in Th2 responses. Ex vivo restimulation of T cells showed decreases in IL-4, IL-5, IL-13, IL-6, and IL-17 levels, suggesting that T cell functions were disrupted. In vitro studies indicated that blockade of the H4R on dendritic cells leads to decreases in cytokine and chemokine production and limits their ability to induce Th2 responses in T cells. This work suggests that the H4R can modulate allergic responses via its influence on T cell activation. The study expands the known influences of histamine on the immune system and highlights the therapeutic potential of H4R antagonists in allergic conditions.

Topics: Allergens; Animals; Benzimidazoles; CD4-Positive T-Lymphocytes; Cells, Cultured; Cytokines; Disease Models, Animal; Female; Indoles; Inflammation; Lung; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Mice, Knockout; Mice, Mutant Strains; Mice, Transgenic; Ovalbumin; Piperazines; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H4; Respiratory Hypersensitivity

Histamine mediates its physiological function through binding to four known histamine receptors. Here, we describe the first selective antagonist of the histamine H4 receptor, the newest member of the histamine receptor family, and provide evidence that such antagonists have anti-inflammatory activity in vivo. 1-[(5-chloro-1H-indol-2-yl)carbonyl]-4-methylpiperazine (JNJ 7777120) has a K(i) of 4.5 nM versus the human receptor and a pA(2) of 8.1. It is equipotent against the human, mouse, and rat receptors. It exhibits at least 1000-fold selectivity over H1, H2, or H3 receptors and has no cross-reactivity against 50 other targets. This compound has an oral bioavailability of approximately 30% in rats and 100% in dogs, with a half-life of approximately 3 h in both species. JNJ 7777120 blocks histamine-induced chemotaxis and calcium influx in mouse bone marrow-derived mast cells. In addition, it can block the histamine-induced migration of tracheal mast cells from the connective tissue toward the epithelium in mice. JNJ 7777120 significantly blocks neutrophil infiltration in a mouse zymosan-induced peritonitis model. This model is reported to be mast cell-dependent, which suggests that the compound effect may be mediated by mast cells. These results indicate that the histamine H4 receptor plays a role in the inflammatory process. Selective H4 receptor antagonists like JNJ 7777120 may have the potential to be useful in treating inflammation in humans.

Topics: Animals; Anti-Inflammatory Agents; Cell Movement; Cells, Cultured; Disease Models, Animal; Female; Histamine Antagonists; Humans; Indoles; Inflammation; Male; Mast Cells; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Pain; Piperazines; Rats; Receptors, G-Protein-Coupled; Receptors, Histamine; Receptors, Histamine H4