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1.
Am J Vet Res ; 82(11): 890-896, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34669495

RESUMO

OBJECTIVE: To determine the effects of leukoreduction on N-methylhistamine (NMH; a stable histamine metabolite) concentration in units of canine whole blood during storage and incubation at room temperature (approx 22 °C) to simulate temperature conditions during transfusion. ANIMALS: 8 healthy adult Walker Hounds. PROCEDURES: A standard unit of blood (450 mL) was obtained from each dog twice, with at least 28 days between donations. Blood units collected from 4 dogs during the first donation underwent leukoreduction, whereas the blood units collected from the other 4 dogs did not undergo leukoreduction, prior to storage at 4 °C. The alternate treatment was applied to blood units collected during the second donation. A sample from each unit was obtained for determination of plasma NMH concentration the day of donation (before and after leukoreduction when applicable) and before and after incubation at room temperature for 5 hours on days 14 and 28 of storage. RESULTS: Units that underwent leukoreduction had substantially lower leukocyte and platelet counts than nonleukoreduced units. Plasma NMH concentration increased immediately after leukoreduction but did not change significantly during the subsequent 28 days of storage, nor did it differ between units that did and did not undergo leukoreduction. CONCLUSIONS AND CLINICAL RELEVANCE: Leukoreduction and simulated transfusion temperature did not affect the histamine load in units of canine whole blood during the first 28 days of storage. Further research is necessary to determine whether histamine contributes to the development and severity of blood transfusion reactions in dogs.


Assuntos
Preservação de Sangue , Eritrócitos , Animais , Preservação de Sangue/veterinária , Cães , Leucócitos , Metilistaminas
2.
Biomolecules ; 11(8)2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34439832

RESUMO

Two histamine receptor subtypes (HR), namely H1R and H4R, are involved in the transmission of histamine-induced itch as key components. Although exact downstream signaling mechanisms are still elusive, transient receptor potential (TRP) ion channels play important roles in the sensation of histaminergic and non-histaminergic itch. The aim of this study was to investigate the involvement of TRPV1 and TRPA1 channels in the transmission of histaminergic itch. The potential of TRPV1 and TRPA1 inhibitors to modulate H1R- and H4R-induced signal transmission was tested in a scratching assay in mice in vivo as well as via Ca2+ imaging of murine sensory dorsal root ganglia (DRG) neurons in vitro. TRPV1 inhibition led to a reduction of H1R- and H4R- induced itch, whereas TRPA1 inhibition reduced H4R- but not H1R-induced itch. TRPV1 and TRPA1 inhibition resulted in a reduced Ca2+ influx into sensory neurons in vitro. In conclusion, these results indicate that both channels, TRPV1 and TRPA1, are involved in the transmission of histamine-induced pruritus.


Assuntos
Cálcio/metabolismo , Gânglios Espinais/metabolismo , Prurido/genética , Células Receptoras Sensoriais/metabolismo , Canal de Cátion TRPA1/genética , Canais de Cátion TRPV/genética , Acetanilidas/farmacologia , Animais , Capsaicina/análogos & derivados , Capsaicina/farmacologia , Feminino , Gânglios Espinais/efeitos dos fármacos , Expressão Gênica , Histamina/administração & dosagem , Masculino , Metilistaminas/administração & dosagem , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Imagem Molecular , Cultura Primária de Células , Prurido/induzido quimicamente , Prurido/tratamento farmacológico , Prurido/metabolismo , Purinas/farmacologia , Rutênio Vermelho/farmacologia , Células Receptoras Sensoriais/efeitos dos fármacos , Transdução de Sinais , Canal de Cátion TRPA1/antagonistas & inibidores , Canal de Cátion TRPA1/metabolismo , Canais de Cátion TRPV/antagonistas & inibidores , Canais de Cátion TRPV/metabolismo
4.
Psychopharmacology (Berl) ; 238(6): 1495-1511, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33550481

RESUMO

RATIONALE: Samelisant (SUVN-G3031) is a potent and selective histamine H3 receptor (H3R) inverse agonist with good brain penetration and oral bioavailability. OBJECTIVES: Pharmacological and neurochemical characterisation to support the utility of Samelisant (SUVN-G3031) in the treatment of sleep-related disorders like narcolepsy. METHODS: Samelisant (SUVN-G3031) was tested in rat brain microdialysis studies for evaluation of modulation in histamine, dopamine and norepinephrine. Sleep EEG studies were carried out in orexin knockout mice to study the effects of Samelisant (SUVN-G3031) on the sleep-wake cycle and cataplexy. RESULTS: Samelisant (SUVN-G3031) has a similar binding affinity towards human (hH3R; Ki = 8.7 nM) and rat (rH3R; Ki = 9.8 nM) H3R indicating no inter-species differences. Samelisant (SUVN-G3031) displays inverse agonist activity and it exhibits very high selectivity towards H3R. Samelisant (SUVN-G3031) treatment in mice produced a dose-dependent increase in tele-methylhistamine levels indicating the activation of histaminergic neurotransmission. Apart from increasing the levels of histamine, Samelisant (SUVN-G3031) also modulates dopamine and norepinephrine levels in the cerebral cortex while it has no effects on dopamine levels in the striatum or nucleus accumbens. Treatment with Samelisant (SUVN-G3031; 10 and 30 mg/kg, p.o.) produced a significant increase in wakefulness with a concomitant decrease in NREM sleep in orexin knockout mice subjected to sleep EEG. Samelisant (SUVN-G3031) also produced a significant decrease in Direct REM sleep onset (DREM) episodes, demonstrating its anticataplectic effects in an animal model relevant to narcolepsy. Modulation in cortical levels of histamine, norepinephrine and dopamine provides the neurochemical basis for wake-promoting and anticataplectic effects observed in orexin knockout mice. CONCLUSIONS: Pre-clinical studies of Samelisant (SUVN-G3031) provide a strong support for utility in the treatment of sleep-related disorders related to EDS and is currently being evaluated in a phase 2 proof of concept study in the USA for the treatment of narcolepsy with and without cataplexy.


Assuntos
Agonistas dos Receptores Histamínicos/farmacologia , Morfolinas/farmacologia , Narcolepsia/tratamento farmacológico , Piperidinas/farmacologia , Animais , Eletroencefalografia , Histamina/metabolismo , Humanos , Masculino , Metilistaminas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Orexinas/genética , Ratos , Ratos Wistar , Sono/efeitos dos fármacos , Vigília/efeitos dos fármacos
5.
Yakugaku Zasshi ; 141(1): 93-110, 2021.
Artigo em Japonês | MEDLINE | ID: mdl-33390452

RESUMO

There has been little information about the role of histamine on the central nervous system (CNS), different from dopamine and serotonin. In the present study, therefore, the effects of histamine and related compounds on the CNS were studied using rats. Intracerebroventricular (i.c.v.) injection of histamine and 2-methylhistamine ameliorated memory deficit after long interrution of learning in active avoidance response. First generation H1-antagonists inhibited active avoidance response, whereas newly develpoed H1-antagonists showed little effect. α-Fluoromethylhistidine, an histidine decarboxylase inhibitor, also inhibited active avoidance response. In radial maze performance, almost the same findings were obtained. I.c.v. injection of histamine and H1-agonists inhibited amygdaloid kindled seizures. First generation H1-antagonists attenuated histamine-induced inhibition of amygdaloid kindled seizures. Both i.c.v. and intraperitoneal injections of H3-antagonist, thioperamide, resulted in a dose-related inhibition of amygdaloid kindled seizures. The effect of thioperamide was inhibited by an H3-agonists and H1-antagonists. Similar to nitrazepam, diphenhydramine and chlorpheniramine caused a shortening of sleep latency. On the other hand, no significant effects were observed with second generation H1-antagonists. These findings suggest that histamine plays an important role in learning and memory via H1-receptors, an inhibition of amygdaloid kindled seizures induced by histamine occurred through not only H1-receptors but also H3-receptors, and that classic H1-antagonists can be useful as a effective hypnotic for difficulty in falling asleep.


Assuntos
Sistema Nervoso Central/efeitos dos fármacos , Antagonistas dos Receptores Histamínicos H1/farmacologia , Histamina/farmacologia , Metilistaminas/farmacologia , Metilistidinas/farmacologia , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Histamina/administração & dosagem , Histamina/metabolismo , Histamina/fisiologia , Antagonistas dos Receptores Histamínicos H1/uso terapêutico , Humanos , Hipnóticos e Sedativos , Injeções Intraventriculares , Excitação Neurológica/efeitos dos fármacos , Transtornos da Memória/tratamento farmacológico , Metilistaminas/administração & dosagem , Metilistidinas/administração & dosagem , Camundongos , Ratos , Receptores Histamínicos H3/metabolismo , Receptores Histamínicos H3/fisiologia , Convulsões/tratamento farmacológico , Sono/efeitos dos fármacos , Distúrbios do Início e da Manutenção do Sono/tratamento farmacológico
6.
Cell Mol Neurobiol ; 41(1): 185-190, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32211996

RESUMO

Motoneuron activity is modulated by histamine receptors. While H1 and H2 receptors have been widely explored, H3 histamine receptors (H3Rs) have not been sufficiently characterized. This paper targets the effects of the selective activation of H3Rs and their expression on the membranes of large ventral horn cells. The application of selective pharmacological agents to spinal cords isolated from neonatal rats was used to identify the presence of functional H3Rs on the membrane of physiologically identified lumbar motoneurons. Intra and extracellular recordings revealed that H3R agonist, α-methylhistamine, depolarized both single motoneurons and ventral roots, even in the presence of tetrodotoxin, an effect prevented by H3R antagonist, thioperamide. Finally, immunohistochemistry located the expression of H3Rs on a subpopulation of large cells in lamina IX. This study identifies H3Rs as a new exploitable pharmacological target against motor disturbances.


Assuntos
Neurônios Motores/metabolismo , Receptores Histamínicos/metabolismo , Corno Ventral da Medula Espinal/metabolismo , Animais , Metilistaminas/farmacologia , Neurônios Motores/efeitos dos fármacos , Ratos , Corno Ventral da Medula Espinal/efeitos dos fármacos
7.
J Neuroinflammation ; 17(1): 217, 2020 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-32698899

RESUMO

BACKGROUND: Microglia, the principal sentinel immune cells of the central nervous system (CNS), play an extensively vital role in neuroinflammation and perioperative neurocognitive disorders (PND). Histamine, a potent mediator of inflammation, can both promote and prevent microglia-related neuroinflammation by activating different histamine receptors. Rat microglia express four histamine receptors (H1R, H2R, H3R, and H4R), among which the histamine 1 and 4 receptors can promote microglia activation, whereas the role and cellular mechanism of the histamine 2 and 3 receptors have not been elucidated. Therefore, we evaluated the effects and potential cellular mechanisms of histamine 2/3 receptors in microglia-mediated inflammation and PND. METHODS: This study investigated the role of histamine 2/3 receptors in microglia-induced inflammation and PND both in vivo and in vitro. In the in vivo experiments, rats were injected with histamine 2/3 receptor agonists in the right lateral ventricle and were then subjected to exploratory laparotomy. In the in vitro experiments, primary microglia were pretreated with histamine 2/3 receptor agonists before stimulation with lipopolysaccharide (LPS). Cognitive function, microglia activation, proinflammatory cytokine production, NF-κb expression, M1/M2 phenotypes, cell migration, and Toll-like receptor-4 (TLR4) expression were assessed. RESULTS: In our study, the histamine 2/3 receptor agonists inhibited exploratory laparotomy- or LPS-induced cognitive decline, microglia activation, proinflammatory cytokine production, NF-κb expression, M1/M2 phenotype transformation, cell migration, and TLR4 expression through the PI3K/AKT/FoxO1 pathway. CONCLUSION: Based on our findings, we conclude that histamine 2/3 receptors ameliorate PND by inhibiting microglia activation through the PI3K/AKT/FoxO1 pathway. Our results highlight histamine 2/3 receptors as potential therapeutic targets to treat neurological conditions associated with PND.


Assuntos
Agonistas dos Receptores Histamínicos/farmacologia , Microglia/efeitos dos fármacos , Complicações Cognitivas Pós-Operatórias/imunologia , Complicações Cognitivas Pós-Operatórias/metabolismo , Envelhecimento , Animais , Método Duplo-Cego , Proteína Forkhead Box O1/efeitos dos fármacos , Injeções Intraventriculares , Masculino , Metilistaminas/farmacologia , Fosfatidilinositol 3-Quinases/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Receptores Histamínicos , Transdução de Sinais/efeitos dos fármacos , Tiazóis/farmacologia
8.
Biomolecules ; 10(2)2020 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-32013143

RESUMO

We used a combination of density functional theory (DFT) calculations and the implicit quantization of the acidic N-H and O-H bonds to assess the effect of deuteration on the binding of agonists (2-methylhistamine and 4-methylhistamine) and antagonists (cimetidine and famotidine) to the histamine H2 receptor. The results show that deuteration significantly increases the affinity for 4-methylhistamine and reduces it for 2-methylhistamine, while leaving it unchanged for both antagonists, which is found in excellent agreement with experiments. The revealed trends are interpreted in the light of the altered strength of the hydrogen bonding upon deuteration, known as the Ubbelohde effect, which affects ligand interactions with both active sites residues and solvent molecules preceding the binding, thus providing strong evidence for the relevance of hydrogen bonding for this process. In addition, computations further underline an important role of the Tyr250 residue for the binding. The obtained insight is relevant for the therapy in the context of (per)deuterated drugs that are expected to enter therapeutic practice in the near future, while this approach may contribute towards understanding receptor activation and its discrimination between agonists and antagonists.


Assuntos
Deutério/química , Ligação de Hidrogênio , Ligantes , Receptores Histamínicos H2/química , Sítios de Ligação , Cimetidina/química , Teoria da Densidade Funcional , Desenho de Fármacos , Famotidina/química , Humanos , Metilistaminas/química , Distribuição Normal , Ligação Proteica , Prótons , Água/química
9.
Int Arch Allergy Immunol ; 181(1): 43-50, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31722348

RESUMO

INTRODUCTION: Although 4 mast cell mediators can be routinely measured, the results of initial testing to evaluate symptoms of mast cell activation have not been widely reported. OBJECTIVE: We examined the results of mast cell mediator tests used to assess patients with mast cell activation symptoms during a 5-year time span. METHODS: After excluding patients with alternative diagnoses, records of 108 patients were reviewed for initial mediator test results. Mediators included serum tryptase plus urinary N-methyl histamine (N-MH), leukotriene (LT)E4, and 11ß-prostaglandin (PG) F2α or 2,3-dinor-11ß-PGF2α (BPG). RESULTS: Most commonly, either a single measured elevation of 1 mediator (48.1%) or elevations of 2 (33.3%) mediators was found at baseline, during symptoms or at both time points. Elevated levels of a single mediator in order of frequency were: BPG > tryptase > LTE4 > N-MH, and for two mediators: BPG + tryptase (n = 16 cases) > BPG + LTE4 (n = 9) > BPG + N-MH (n = 6). Elevations in 3 mediators (n = 8) or 4 mediators (n = 2) were much less frequent. Monoclonal mast cell activation syndrome (n = 6), and systemic and cutaneous mastocytosis (n = 4) were also infrequent. Baseline plus symptom-associated tryptase values were obtained in only 7 patients. CONCLUSIONS: This survey suggests that elevations of 1 or 2 mediators are the most common (total 81.4% of cases) findings from initial tests for mast cell activation. Elevated levels of BPG were most commonly found both singly and in combination with other mediators, followed by the finding of elevated levels of tryptase. Baseline plus symptom-associated tryptase levels were measured in only a minority of patients.


Assuntos
Dinoprosta/urina , Leucotrieno E4/urina , Mastócitos/fisiologia , Mastocitose/imunologia , Metilistaminas/urina , Triptases/sangue , Dinoprosta/análogos & derivados , Rubor , Humanos , Inquéritos e Questionários
10.
Am J Physiol Endocrinol Metab ; 317(6): E1158-E1171, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31550180

RESUMO

Although many studies have shown that histamine and its signaling regulate energy homeostasis through the central nervous system, their roles in adipose tissues remain poorly understood. Here, we identified that the histamine H4 receptor (HrH4) was highly expressed in adipocytes at a level higher than that of the other three receptors (i.e., HrH1, HrH2, and HrH3). The HrH4 expression in adipocytes responded to cold through thermogenesis and lipolysis, supported by results from both mouse and cell models. When HrH4 expression was knocked down in the subcutaneous white adipose tissue (scWAT), browning and lipolysis effects triggered by cold were ablated, and the oxygen consumption was also lowered both at the normal and cold conditions. Moreover, mice exhibited browned scWAT, accelerated metabolic rates, and tolerance to hypothermia when 4-methylhistamine (4MH), a selective HrH4 agonist, was adjacently injected to the scWAT. Consistent with these findings, 4MH also triggered the browning and lipolytic effects in cultured C3H10T1/2 adipocytes. Mechanically, we demonstrated that p38/MAPK and ERK/MAPK pathways were involved in these processes. In conclusion, our findings have uncovered an effective role of HrH4 in adipose tissue browning.


Assuntos
Adipócitos/metabolismo , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Temperatura Baixa , Consumo de Oxigênio/genética , Receptores Histamínicos H4/genética , Gordura Subcutânea/metabolismo , Termogênese/genética , Células 3T3-L1 , Adipócitos/efeitos dos fármacos , Tecido Adiposo Branco/efeitos dos fármacos , Animais , Metabolismo Basal/efeitos dos fármacos , Metabolismo Basal/genética , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Técnicas de Silenciamento de Genes , Agonistas dos Receptores Histamínicos/farmacologia , Lipólise/efeitos dos fármacos , Lipólise/genética , Sistema de Sinalização das MAP Quinases , Metilistaminas/farmacologia , Camundongos , Consumo de Oxigênio/efeitos dos fármacos , Receptores Histamínicos H4/agonistas , Receptores Histamínicos H4/metabolismo , Gordura Subcutânea/efeitos dos fármacos , Termogênese/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
11.
Comp Med ; 69(2): 130-134, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30803469

RESUMO

Chronic lymphocytic enteritis (CLE) is a frequent disease in common marmosets. However, no diagnostic test for early detection of CLE is available. Mast cells have an important role in gastrointestinal disease. The purpose of this study was to measure fecal concentrations of N-methylhistamine (NMH), a breakdown product of histamine metabolism, in common marmosets. A previously established NMH gas chromatography-mass spectrometry assay for canine feces and urine was used, and partial validation was performed. The reference intervals (n = 30) established for fecal NMH concentrations in common marmoset were 118.2 ng/g or less for a single fecal sample, 121.7 ng/g or less for the 3-d mean, and less than or equal to 167.5 ng/g for the 3-d maximum. Considerable day-to-day variation was observed in fecal NMH concentrations; the mean %CV was 42.2% (minimum, 7.1%; maximum, 141.4%). Fecal NMH concentrations were measured in 14 marmosets for which necropsy reports were available; 7 of the 8 marmosets with CLE and the 1 animal with lymphoma and ulcerative enteritis had increased fecal NMH concentrations. Increased fecal NMH concentrations may serve as a potential marker for CLE; however, further studies exploring the role of mast cells in marmosets with CLE are needed.


Assuntos
Enterite/veterinária , Doenças dos Macacos/metabolismo , Animais , Biomarcadores/metabolismo , Callithrix , Enterite/metabolismo , Fezes , Feminino , Masculino , Metilistaminas/metabolismo
12.
CNS Neurosci Ther ; 25(3): 386-395, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30225986

RESUMO

OBJECTIVE: Narcolepsy is a sleep disorder characterized in humans by excessive daytime sleepiness and cataplexy. Greater than fifty percent of narcoleptic patients have an onset of symptoms prior to the age of 18. Current general agreement considers the loss of hypothalamic hypocretin (orexin) neurons as the direct cause of narcolepsy notably cataplexy. To assess whether brain histamine (HA) is also involved, we quantified the cerebrospinal fluid (CSF) levels of HA and tele-methylhistamine (t-MeHA), the direct metabolite of HA between children with orexin-deficient narcolepsy type 1 (NT1) and controls. METHODS: We included 24 children with NT1 (12.3 ± 3.6 years, 11 boys, 83% cataplexy, 100% HLA DQB1*06:02) and 21 control children (11.2 ± 4.2 years, 10 boys). CSF HA and t-MeHA were measured in all subjects using a highly sensitive liquid chromatographic-electrospray/tandem mass spectrometric assay. CSF hypocretin-1 values were determined in the narcoleptic patients. RESULTS: Compared with the controls, NT1 children had higher CSF HA levels (771 vs 234 pmol/L, P < 0.001), lower t-MeHA levels (879 vs 1924 pmol/L, P < 0.001), and lower t-MeHA/HA ratios (1.1 vs 8.2, P < 0.001). NT1 patients had higher BMI z-scores (2.7 ± 1.6 vs 1.0 ± 2.3, P = 0.006) and were more often obese (58% vs 29%, P = 0.05) than the controls. Multivariable analyses including age, gender, and BMI z-score showed a significant decrease in CSF HA levels when the BMI z-score increased in patients (P = 0.007) but not in the controls. No association was found between CSF HA, t-MeHA, disease duration, age at disease onset, the presence of cataplexy, lumbar puncture timing, and CSF hypocretin levels. CONCLUSIONS: Narcolepsy type 1 children had a higher CSF HA level together with a lower t-MeHA level leading to a significant decrease in the t-MeHA/HA ratios. These results suggest a decreased HA turnover and an impairment of histaminergic neurotransmission in narcoleptic children and support the use of a histaminergic therapy in the treatment against narcolepsy.


Assuntos
Histamina/líquido cefalorraquidiano , Narcolepsia/líquido cefalorraquidiano , Adolescente , Índice de Massa Corporal , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Metilistaminas/líquido cefalorraquidiano , Orexinas/líquido cefalorraquidiano , Transmissão Sináptica
13.
Clin Cancer Res ; 24(20): 5085-5097, 2018 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-30084838

RESUMO

Purpose: Kaposi sarcoma (KS) is a vascular tumor initiated by infection of endothelial cells (ECs) with KS-associated herpesvirus (KSHV). KS is dependent on sustained proinflammatory signals provided by intralesional leukocytes and continued infection of new ECs. However, the sources of these cytokines and infectious virus within lesions are not fully understood. Here, mast cells (MCs) are identified as proinflammatory cells within KS lesions that are permissive for, and activated by, infection with KSHV.Experimental Design: Three validated MC lines were used to assess permissivity of MCs to infection with KSHV and to evaluate MCs activation following infection. Biopsies from 31 AIDS-KS cases and 11 AIDS controls were evaluated by IHC for the presence of MCs in KS lesions and assessment of MC activation state and infection with KSHV. Plasma samples from 26 AIDS-KS, 13 classic KS, and 13 healthy adults were evaluated for levels of MC granule contents tryptase and histamine.Results: In culture, MCs supported latent and lytic KSHV infection, and infection-induced MC degranulation. Within KS lesions, MCs were closely associated with spindle cells. Furthermore, MC activation was extensive within patients with KS, reflected by elevated circulating levels of tryptase and a histamine metabolite. One patient with clinical signs of extensive MC activation was treated with antagonists of MC proinflammatory mediators, which resulted in a rapid and durable regression of AIDS-KS lesions.Conclusions: Using complimentary in vitro and in vivo studies we identify MCs as a potential long-lived reservoir for KSHV and a source of proinflammatory mediators within the KS lesional microenvironment. In addition, we identify MC antagonists as a promising novel therapeutic approach for KS. Clin Cancer Res; 24(20); 5085-97. ©2018 AACR.


Assuntos
Infecções por Herpesviridae/complicações , Infecções por Herpesviridae/virologia , Herpesvirus Humano 8 , Mastócitos/imunologia , Sarcoma de Kaposi/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Citocinas/metabolismo , Suscetibilidade a Doenças , Feminino , Humanos , Imuno-Histoquímica , Masculino , Mastócitos/metabolismo , Metilistaminas/metabolismo , Pessoa de Meia-Idade , Modelos Biológicos , Sarcoma de Kaposi/metabolismo , Sarcoma de Kaposi/patologia , Pele/metabolismo , Pele/patologia , Triptases/metabolismo
14.
J Recept Signal Transduct Res ; 38(3): 204-212, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29863427

RESUMO

CONTEXT: Mast cell (MC) activation through H4R releases various inflammatory mediators which are associated with allergic asthma. OBJECTIVES: To investigate the siRNA-mediated gene silencing effect of H4R on human mast cells (HMCs) functions and the activation of stress-activated protein kinases (SAPK)/jun amino-terminal kinases (JNK) signaling pathways for the release of ineterleukin-1ß (IL-1ß) in HMCs. MATERIALS AND METHODS: H4R expression was analyzed by RT-PCR and western blotting in human mast cell line-1 (HMC-1) cells and H4RsiRNA transfected cells. The effect of H4RsiRNA and H4R-antagonist on H4R mediated MC functions such as intracellular Ca2+ release, degranulation, IL-6 and IL-1ß release, and the activation SAPK/JNK signaling pathways were studied. HMC-1 cells were stimulated with 10 µM of histamine (His) and 4-methylhistamine (4-MH) and pretreated individually with H4R-antagonist JNJ7777120 (JNJ), histamine H1 receptor (H1R)-antagonist mepyramine, and signaling molecule inhibitors SP600125 (SP) and Bay117082. RESULTS: We found that the HMC-1 cells expressed H4R and H4RsiRNA treatment down regulated the H4R expression in HMC-1 cells. Both His and 4-MH induced the intracellular Ca2+ release and degranulation whereas; H4R siRNA and JNJ inhibited the effect. Furthermore, the activation of H4R caused the phosphorylation of SAPK/JNK pathways. H4R gene silencing and pretreatment with SP and JNJ decreased His and 4-MH induced phosphorylation of SAPK/JNK. We found that the activation of H4R caused the release of IL-1ß (124.22 pg/ml) and IL-6 (122.50 pg/ml) on HMC-1 cells. Whereas, SAPK/JNK inhibitor (68.36 pg/ml) inhibited the H4R mediated IL-1ß release. CONCLUSIONS: Taken together, the silencing of H4R inhibited the H4R mediated MC functions and SAPK/JNK phosphorylation. Furthermore, the H4R activation utilized SAPK/JNK signaling pathway for IL-1ß release in HMC-1 cells.


Assuntos
Interleucina-1beta/genética , MAP Quinase Quinase 4/genética , Mastócitos/metabolismo , Receptores Histamínicos H4/genética , Cálcio/metabolismo , Linhagem Celular , Regulação da Expressão Gênica/efeitos dos fármacos , Inativação Gênica , Histamina/farmacologia , Humanos , Indóis/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Mastócitos/efeitos dos fármacos , Metilistaminas/farmacologia , Piperazinas/farmacologia , Pirilamina/farmacologia , RNA Interferente Pequeno/genética , Receptores Histamínicos H4/antagonistas & inibidores
15.
Biochim Biophys Acta Mol Basis Dis ; 1864(9 Pt B): 3050-3059, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29953926

RESUMO

Monoamine oxidase (MAO), a mitochondrial enzyme that oxidizes biogenic amines generating hydrogen peroxide, is a major source of oxidative stress in cardiac injury. However, the molecular mechanisms underlying its overactivation in pathological conditions are still poorly characterized. Here, we investigated whether the enhanced MAO-dependent hydrogen peroxide production can be due to increased substrate availability using a metabolomic profiling method. We identified N1-methylhistamine -the main catabolite of histamine- as an important substrate fueling MAO in Langendorff mouse hearts, directly perfused with a buffer containing hydrogen peroxide or subjected to ischemia/reperfusion protocol. Indeed, when these hearts were pretreated with the MAO inhibitor pargyline we observed N1-methylhistamine accumulation along with reduced oxidative stress. Next, we showed that synaptic terminals are the major source of N1-methylhistamine. Indeed, in vivo sympathectomy caused a decrease of N1-methylhistamine levels, which was associated with a marked protection in post-ischemic reperfused hearts. As far as the mechanism is concerned, we demonstrate that exogenous histamine is transported into isolated cardiomyocytes and triggers a rise in the levels of reactive oxygen species (ROS). Once again, pargyline pretreatment induced intracellular accumulation of N1-methylhistamine along with decrease in ROS levels. These findings uncover a receptor-independent mechanism for histamine in cardiomyocytes. In summary, our study reveals a novel and important pathophysiological causative link between MAO activation and histamine availability during pathophysiological conditions such as oxidative stress/cardiac injury.


Assuntos
Ventrículos do Coração/patologia , Histamina/metabolismo , Monoaminoxidase/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Miocárdio/patologia , Animais , Modelos Animais de Doenças , Ventrículos do Coração/citologia , Humanos , Preparação de Coração Isolado , Masculino , Metabolômica , Metilistaminas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Inibidores da Monoaminoxidase/farmacologia , Traumatismo por Reperfusão Miocárdica/etiologia , Miocárdio/citologia , Miocárdio/metabolismo , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Oxirredução , Estresse Oxidativo , Pargilina/farmacologia , Espécies Reativas de Oxigênio/metabolismo
16.
Drug Des Devel Ther ; 12: 179-194, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29403264

RESUMO

The imidazole-based H3R antagonist 2-18 with high in vitro H3R antagonist affinity, excellent in vitro selectivity profile, and high in vivo H3R antagonist potency was tested for its anticonvulsant effect in maximal electroshock (MES)-induced convulsions in mice having valproic acid (VPA) as a reference antiepileptic drug (AED). Additionally, H3R antagonist 2-18 was evaluated for its reproductive toxicity in the same animal species. The results show that acute systemic administration (intraperitoneal; i.p.) of H3R antagonist 2-18 (7.5, 15, 30, and 60 mg/kg, i.p.) significantly and dose dependently protected male as well as female mice against MES-induced convulsion. The protective action observed for H3R antagonist 2-18 in both mice sexes was comparable to that of VPA and was reversed when mice were pretreated with the selective H3R agonist (R)-alpha-methylhistamine (RAMH, 10 mg/kg, i.p.). Moreover, the results show that acute systemic administration of single (7.5, 15, 30, or 60 mg/kg, i.p.) or multiple doses (15×3 mg/kg, i.p.) of H3R antagonist 2-18 on gestation day (GD) 8 or 13 did not affect the maternal body weight of mice when compared with the control group. Furthermore, no significant differences were observed in the average number of implantations and resorptions between the control and H3R antagonist 2-18-treated group at the early stages of gestation and the organogenesis period. However, oral treatment with H3R antagonist 2-18 (15 mg/kg) on GD 8 induced a reduced number of live embryos when compared with the i.p.-treated mice. In addition, no significant changes in the fetal body and placental weights were observed after injection of H3R antagonist 2-18 with all selected doses. However, three dose groups of i.p. and oral 15 mg/kg on GD 13 significantly affected the placental weight when compared with control group. Notably, the treatment of pregnant female with the H3R antagonist 2-18 did not produce significant malformation in the fetus in both groups. In conclusion, the novel H3R antagonist 2-18 proves to be a very safe compound and displays a low incidence of malformations, demonstrating that H3R antagonist 2-18 may have a potential future therapeutic value in epilepsy.


Assuntos
Anticonvulsivantes/farmacologia , Antagonistas dos Receptores Histamínicos H3/farmacologia , Antagonistas dos Receptores Histamínicos H3/toxicidade , Imidazóis/farmacologia , Imidazóis/toxicidade , Teratógenos/toxicidade , Anormalidades Induzidas por Medicamentos/patologia , Animais , Peso Corporal/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Feto/efeitos dos fármacos , Masculino , Metilistaminas/farmacologia , Metilistaminas/toxicidade , Camundongos , Organogênese/efeitos dos fármacos , Placenta/efeitos dos fármacos , Gravidez , Ácido Valproico/farmacologia , Ácido Valproico/toxicidade
17.
Neuroscience ; 376: 188-203, 2018 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-29374538

RESUMO

Histamine H3 receptors are widely distributed Gi-coupled receptors whose activation reduces neuronal activity and inhibits release of numerous neurotransmitters. Although these receptors are abundantly expressed in the striatum, their modulatory role on activity-dependent dopamine release is not well understood. Here, we observed that histamine H3 receptor activation indirectly diminishes dopamine overflow in the ventral striatum by reducing cholinergic interneuron activity. Acute brain slices from C57BL/6 or channelrhodopsin-2-transfected DAT-cre mice were obtained, and dopamine transients evoked either electrically or optogenetically were measured by fast-scan cyclic voltammetry. The H3 agonist α-methylhistamine significantly reduced electrically- evoked dopamine overflow, an effect blocked by the nicotinic acetylcholine receptor antagonist dihydro-ß-erythroidine, suggesting involvement of cholinergic interneurons. None of the drug treatments targeting H3 receptors affected optogenetically evoked dopamine overflow, indicating that direct H3-modulation of dopaminergic axons is unlikely. Next, we used qPCR and confirmed the expression of histamine H3 receptor mRNA in cholinergic interneurons, both in ventral and dorsal striatum. Activation of H3 receptors by α-methylhistamine reduced spontaneous firing of cholinergic interneurons in the ventral, but not in the dorsal striatum. Resting membrane potential and number of spontaneous action potentials in ventral-striatal cholinergic interneurons were significantly reduced by α-methylhistamine. Acetylcholine release from isolated striatal synaptosomes, however, was not altered by α-methylhistamine. Together, these results indicate that histamine H3 receptors are important modulators of dopamine release, specifically in the ventral striatum, and that they do so by decreasing the firing rate of cholinergic neurons and, consequently, reducing cholinergic tone on dopaminergic axons.


Assuntos
Acetilcolina/metabolismo , Dopamina/metabolismo , Interneurônios/metabolismo , Receptores Histamínicos H3/metabolismo , Estriado Ventral/metabolismo , Animais , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Feminino , Agonistas dos Receptores Histamínicos/farmacologia , Interneurônios/efeitos dos fármacos , Masculino , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Metilistaminas/farmacologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Optogenética , RNA Mensageiro/metabolismo , Sinaptossomos/metabolismo , Técnicas de Cultura de Tecidos , Estriado Ventral/efeitos dos fármacos
18.
J Pharm Biomed Anal ; 145: 379-385, 2017 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-28715791

RESUMO

Histamine intolerance is a disorder in the homeostasis of histamine due to a reduced intestinal degradation of this amine, mainly caused by diamine oxidase (DAO) enzyme deficiency, which provokes its accumulation in plasma and the appearance of adverse health affects. A new approach for the diagnosis of this intolerance could be the determination of histamine and its metabolites in urine. The aim of this work was to develop and validate a rapid method to determine histamine and methylhistamine in human urine by Ultra High Performance Liquid Chromatography and Fluorimetric detection (UHPLC-FL). The proposed method is a consistent procedure to determine histamine and methylhistamine in less than 11min with adequate linearity and sensitivity. Relative standard deviation was always lower than 5.5%, ensuring method precision; and mean recovery was greater than 99% for both analytes. The structure of histamine and methylhistamine conjugated with OPA were confirmed by UHPLC-ITD-FTMS which enabled to unequivocally identify both analytes in standards and also in urine samples. The analysis of histamine and methylhistamine in urine samples could be a potential new approach for the routine diagnosis of histamine intolerance, more patient-friendly and with clear advantages in terms of equipment and personnel demand for sample collection in comparison with current plasmatic DAO activity determination.


Assuntos
Histamina/urina , Líquidos Corporais , Cromatografia Líquida de Alta Pressão , Fluorometria , Humanos , Metilistaminas
19.
Biochem Biophys Res Commun ; 490(4): 1314-1318, 2017 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-28688766

RESUMO

Recently we found that synthetic compounds containing amino group linked to hydrophobic or aromatic moiety are potent modulators of the proton-gated channels (ASICs). These structures have clear similarity with ligands of histamine receptors. We have also demonstrated that histamine potentiates homomeric ASIC1a by shifting its activation dependence to less acidic conditions. In the present work the action of a series of histamine receptors ligands on recombinant ASIC1a and ASIC2a was characterized. Two types of action were found for ASIC1a. 1-methylhistamine, N-alpha-methylhistamine, dimaprit and thioperamide caused significant potentiation, which was pH-dependent and voltage-independent. The H4R antagonist A943931 caused inhibition, which is likely due to voltage-dependent pore block. ASIC2a were virtually insensitive to the drugs tested. We conclude that ligands of histamine receptors should also be considered as ASIC modulators.


Assuntos
Canais Iônicos Sensíveis a Ácido/genética , Agonistas dos Receptores Histamínicos/farmacologia , Antagonistas dos Receptores Histamínicos/farmacologia , Histamina/farmacologia , Receptores Histamínicos/genética , Canais Iônicos Sensíveis a Ácido/metabolismo , Animais , Células CHO , Cricetulus , Dimaprit/farmacologia , Regulação da Expressão Gênica , Humanos , Concentração de Íons de Hidrogênio , Ligantes , Metilistaminas/farmacologia , Técnicas de Patch-Clamp , Piperidinas/farmacologia , Receptores Histamínicos/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Transdução de Sinais
20.
Sci Rep ; 7(1): 4829, 2017 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-28684785

RESUMO

Virtual screening offers an efficient alternative to high-throughput screening in the identification of pharmacological tools and lead compounds. Virtual screening is typically based on the matching of target structures or ligand pharmacophores to commercial or in-house compound catalogues. This study provides the first proof-of-concept for our recently reported method where pharmacophores are instead constructed based on the inference of residue-ligand fragments from crystal structures. We demonstrate its unique utility for G protein-coupled receptors, which represent the largest families of human membrane proteins and drug targets. We identified five neutral antagonists and one inverse agonist for the histamine H3 receptor with potencies of 0.7-8.5 µM in a recombinant receptor cell-based inositol phosphate accumulation assay and validated their activity using a radioligand competition binding assay. H3 receptor antagonism is of large therapeutic value and our ligands could serve as starting points for further lead optimisation. The six ligands exhibit four chemical scaffolds, whereof three have high novelty in comparison to the known H3 receptor ligands in the ChEMBL database. The complete pharmacophore fragment library is freely available through the GPCR database, GPCRdb, allowing the successful application herein to be repeated for most of the 285 class A GPCR targets. The method could also easily be adapted to other protein families.


Assuntos
Agonistas dos Receptores Histamínicos/química , Antagonistas dos Receptores Histamínicos/química , Fosfatos de Inositol/química , Metilistaminas/química , Receptores Histamínicos H3/química , Sequência de Aminoácidos , Sítios de Ligação , Ligação Competitiva , Cristalografia por Raios X , Bases de Dados de Produtos Farmacêuticos , Expressão Gênica , Células HEK293 , Ensaios de Triagem em Larga Escala , Agonistas dos Receptores Histamínicos/metabolismo , Antagonistas dos Receptores Histamínicos/metabolismo , Humanos , Fosfatos de Inositol/metabolismo , Cinética , Ligantes , Metilistaminas/metabolismo , Simulação de Acoplamento Molecular , Ligação Proteica , Conformação Proteica em alfa-Hélice , Domínios e Motivos de Interação entre Proteínas , Receptores Histamínicos H3/genética , Receptores Histamínicos H3/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Relação Estrutura-Atividade , Termodinâmica , Interface Usuário-Computador
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