RESUMO
Canine leishmaniasis (CanL) is caused by the intracellular parasite Leishmania infantum. Prostaglandin E2 (PGE2 ) exerts potent regulatory effects on the immune system in experimental model Leishmania infection, but this influence has not yet been studied in CanL. In this study, PGE2 and PGE2 receptor levels and the regulatory effect of PGE2 on arginase activity, NO2 , IL-10, IL-17, IFN-γ, TNF-α and parasite load were evaluated in cultures of splenic leucocytes obtained from dogs with CanL in the presence of agonists and inhibitors. Our results showed that splenic leucocytes from dogs with CanL had lower EP2 receptor levels than those of splenic leucocytes from healthy animals. We observed that NO2 levels decreased when the cells were treated with a PGE2 receptor agonist (EP1/EP2/EP3) or COX-2 inhibitor (NS-398) and that TNF-α, IL-17 and IFN-γ cytokine levels decreased when the cells were treated with a PGE2 receptor agonist (EP2) or PGE2 itself. The parasite load in splenic leucocyte cell cultures from dogs with CanL decreased after stimulation of the cells with PGE2 . We conclude that Leishmania infection of dogs modulates PGE2 receptors and speculate that the binding of PGE2 to its receptors may activate the microbicidal capacity of cells.
Assuntos
Citocinas/imunologia , Dinoprostona/metabolismo , Doenças do Cão/tratamento farmacológico , Leishmania infantum/imunologia , Leishmaniose/veterinária , Receptores de Prostaglandina E/metabolismo , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Inibidores de Ciclo-Oxigenase 2/farmacologia , Dinoprostona/agonistas , Dinoprostona/antagonistas & inibidores , Doenças do Cão/imunologia , Doenças do Cão/parasitologia , Cães , Leishmaniose/tratamento farmacológico , Leishmaniose/imunologia , Óxido Nítrico/análise , Nitrobenzenos/farmacologia , Carga Parasitária , Receptores de Prostaglandina E/agonistas , Receptores de Prostaglandina E/fisiologia , Sulfonamidas/farmacologia , Fator de Necrose Tumoral alfa/imunologiaRESUMO
INTRODUCTION: Root canal treatment of immature necrotic teeth is a major challenge in current endodontics. The effect of inflammatory mediators, such as prostaglandin, on the modulation of stem cells of the apical papilla (SCAP) is not completely understood. The aim of this study was to investigate the role of prostaglandin E2 (PGE2) on SCAP activation by Escherichia coli lipopolysaccharide (LPS) in vitro. METHODS: SCAP cultures were established and characterized. Increasing concentrations of lipopolysaccharide (0.1-10 µg/mL) were used to investigate cyclooxygenase-2 (COX-2/PTGS2) and PGE2 receptors (EP1-4) gene expression. Then, SCAP were treated with a COX-2 inhibitor (indomethacin) before treatment with different concentrations of LPS. The levels of the chemokine CCL2/monocyte chemoattractant protein 1 and interleukin (IL)-6 were detected in cell supernatants (24 hours) by enzyme-linked immunosorbent assay. Data analysis was performed using analysis of variance followed by the Tukey post test. RESULTS: The expression of COX-2 was up-regulated in the group treated with LPS at 1µg/mL compared with that in the control group. EP1-4 were detected in all experimental conditions at similar levels. SCAP treated with indomethacin presented a down-regulation in the production of LPS-induced CCL2 and the secretion of IL-6. CONCLUSIONS: SCAP showed increased COX-2 (PTGS2) gene expression induced by LPS and a PGE2-dependent production of IL-6 and CCL2.
Assuntos
Quimiocina CCL2 , Ciclo-Oxigenase 2 , Interleucina-6 , Receptores de Prostaglandina E , Ápice Dentário , Células Cultivadas , Quimiocina CCL2/metabolismo , Ciclo-Oxigenase 2/metabolismo , Humanos , Interleucina-6/fisiologia , Lipopolissacarídeos , Receptores de Prostaglandina E/fisiologia , Células-Tronco , Ápice Dentário/metabolismoRESUMO
OBJECTIVES: The present study examined the mechanisms involved in the antinociceptive effects of bis selenide [(Z)-2,3-bis(4-chlorophenylselanyl)prop-2-en-1-ol]. METHODS: The effects of oral bis selenide were tested against licking behaviour and oedema in mice induced by formalin, serotonin, histamine, glutamate, phorbol 12-myristate 13-acetate (PMA), 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP) and prostaglandin E2. The effects of a variety of receptor antagonists on the antinociceptive activity were tested to determine the likely mechanism of action of bis selenide. KEY FINDINGS: Bis selenide caused antinociception on the first and second phases of the formalin test, with mean ID50 values of 34.21 (29.66-39.45) and 15.86 (12.17-20.67) mg/kg and maximal inhibition of 65+/-3% and 90+/-1%, respectively. At 50 mg/kg bis selenide significantly inhibited (31+/-2%) paw oedema induced by intraplantar injection of formalin. At 25 mg/kg given 5 min after the formalin injection, bis selenide caused a significant inhibition (42+/-5%) in the second phase of the formalin test, whereas the prophylactic treatment caused more intense inhibition (64+/-3%). Oral administration of bis selenide reduced licking and paw oedema induced by serotonin, histamine, glutamate, PGE2, PMA and 8-BrcAMP. The antinociceptive effect of bis selenide (25 mg/kg, p.o.) on the formalin test was reversed by i.p. administration of p-chlorophenylalanine methyl ester (an inhibitor of serotonin synthesis), ketanserin (a selective 5-HT2A receptor antagonist), ondansetron (a 5-HT3 receptor antagonist) and ranitidine (a histamine H2-receptor antagonist). CONCLUSIONS: Glutamatergic, prostaglandin E2, serotonergic (5-HT2A and 5-HT3) and histamine H2 receptors are involved in the antinociceptive effects of bis selenide in mice. The interaction of bis selenide with protein kinase C and A signalling pathways was also demonstrated.
Assuntos
Analgésicos/farmacologia , Edema/tratamento farmacológico , Compostos Organosselênicos/farmacologia , Administração Oral , Animais , Comportamento Animal/efeitos dos fármacos , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Relação Dose-Resposta a Droga , Edema/induzido quimicamente , Feminino , Masculino , Camundongos , Dor/induzido quimicamente , Dor/tratamento farmacológico , Medição da Dor/métodos , Proteína Quinase C/fisiologia , Receptor 5-HT2A de Serotonina/fisiologia , Receptores de Glutamato/fisiologia , Receptores Histamínicos H2/fisiologia , Receptores de Prostaglandina E/fisiologia , Receptores 5-HT3 de Serotonina/fisiologia , Transdução de SinaisRESUMO
There is evidence that prostaglandin E2 (PGE2) facilitates the seizures induced by pentylenetetrazol (PTZ), but the role of PGE2 receptors (EPs) in the development of seizures has not been evaluated to date. In the current study we investigated whether selective EP ligands alter PTZ-induced seizures in adult male Wistar rats by electrographic methods. Selective antagonists for EP1 (SC-19220, 10 nmol, i.c.v.), EP3 (L-826266, 1 nmol, i.c.v.) and EP4 (L-161982, 750 pmol, i.c.v.) receptors, and the selective EP2 agonist butaprost (100 pmol, i.c.v.) increased the latency for clonic and generalized tonic-clonic seizures induced by PTZ. These data constitute pharmacological evidence supporting a role for EPs in the seizures induced by PTZ. Although more studies are necessary to fully evaluate the anticonvulsant role these compounds and their use in the clinics, EP ligands may represent new targets for drug development for convulsive disorders.
Assuntos
Pentilenotetrazol , Antagonistas de Prostaglandina/administração & dosagem , Receptores de Prostaglandina E/fisiologia , Convulsões/induzido quimicamente , Convulsões/metabolismo , Animais , Comportamento Animal/efeitos dos fármacos , Relação Dose-Resposta a Droga , Esquema de Medicação , Masculino , Ratos , Ratos Wistar , Receptores de Prostaglandina E/antagonistas & inibidores , Convulsões/fisiopatologiaRESUMO
BACKGROUND AND PURPOSE: Receptor subtypes involved in PGE(2)-induced nociception are still controversial. The present study investigated the prostanoid E receptor (EP) subtypes and the protein kinase (PK) pathways involved in the nociception induced by PGE(2) injection in the mouse paw. EXPERIMENTAL APPROACH: Paw-licking and mechanical allodynia were measured in vivo and protein kinase activation ex vivo by Western blots of extracts of paw skin. KEY RESULTS: Intraplantar (i.pl.) injection of PGE(2) into the mouse paw caused nociceptive behaviour of short duration with mean ED(50) of 1.43 nmol. PGE(2) produced a longer-lasting mechanical allodynia, with an ED(50) of 0.05 nmol. Intraplantar injection of antagonists at EP(3) or EP(4), but not at EP(1) or EP(2) receptors inhibited PGE(2)-induced paw-licking. Paw-licking caused by PGE(2) was blocked by an inhibitor of PKA but only partially decreased by inhibition of the extracellular-regulated kinase (ERK). Selective inhibitors of PKC, c-Jun N-terminal kinase (JNK) or p38, all failed to affect PGE(2)-induced paw-licking. An EP(3) antagonist inhibited PGE(2)-induced mechanical allodynia. However, inhibitors of PKA, PKC or ERK, but not p38 or JNK, also partially inhibited PGE(2)-induced mechanical allodynia. Western blot analyses confirmed that i.pl. injection of PGE(2) activated PKA, PKCalpha, and mitogen activated kinases (MAPKs) in the paw. Co-treatment with EP(3) or EP(4) receptor antagonists reduced PGE(2)-induced PKA and ERK, but not PKCalpha activation. CONCLUSIONS AND IMPLICATIONS: The present results indicate that the nociceptive behaviour and mechanical allodynia caused by i.pl. PGE(2) are mediated through activation of distinct EP receptors and PK-dependent mechanisms.
Assuntos
Dinoprostona/administração & dosagem , Nociceptores/efeitos dos fármacos , Proteínas Quinases/metabolismo , Receptores de Prostaglandina E/fisiologia , Acrilamidas/administração & dosagem , Animais , Carragenina/administração & dosagem , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Dinoprostona/análogos & derivados , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Técnicas In Vitro , Masculino , Camundongos , Naftalenos/administração & dosagem , Nociceptores/fisiologia , Medição da Dor , Prostaglandinas E Sintéticas/administração & dosagem , Proteína Quinase C/metabolismo , Receptores de Prostaglandina E/antagonistas & inibidores , Receptores de Prostaglandina E/classificação , Estresse MecânicoRESUMO
The present study evaluated some of the mechanisms underlying prostaglandin E2 (PGE2)-induced paw edema formation in mice. Intraplantar (i.pl.) injection of PGE2 (0.10-10.0 nmol/paw) into the hindpaw elicited a dose-related edema formation, with a mean ED50 value of 0.42 nmol/paw. The coinjection of selective E-prostanoid (EP)3 [(2E)-N-[(5-bromo-2-methoxyphenyl)-sulfonyl]-3-[5-chloro-2-(2-naphthylmethyl)phenyl]acrylamide; L826266), but not EP2 or EP4 (all 10 nmol/paw), receptor antagonists significantly inhibited PGE2-induced paw edema. Like L826266, the PGE2-induced paw edema was markedly reduced by treatment with pertussis toxin and phospholipase C (PLC) inhibitor 1-[6-[[17beta-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U-73122). Likewise, the selective neurokinin (NK)1 receptor antagonist N-[(4R)-4-hydroxy-1-(1-methyl-1H-indol-3-yl)carbonyl-l-prolyl]-N-methyl-N-phenyl-methyl-3-(2-aphthyl)-l-alaninamide (FK888) and the antagonist of vanilloid receptor (TRPV1) receptors 4'-chloro-3-methoxycinnamanilide (SB366791) (both 1 nmol/paw) also significantly inhibited PGE2-mediated paw edema. Conversely, the selective NK2, NK3, and calcitonin gene-related peptide (CGRP) CGRP(8-37) receptor antagonists all failed to interfere with PGE2-induced paw edema. The neonatal treatment of mice with capsaicin was also able to reduce PGE2-induced paw edema. The inhibitors of protein kinase C (PKC) 3-[1-[3-(dimethylaminopropyl]-1H-indol-3-yl]-4-(1H-indol-3-yl)-1H-pyrrole-2,5-dione monohydrochloride (GF109203X) and mitogen protein-activated kinases (MAPKs; 30 nmol/paw) c-Jun NH2-terminal kinase (JNK) (anthra[1,9-cd]pyrazol-6(2H)-one; SP600125), extracellular signal-regulated kinase (PD98059), and p38 [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole; SB203580], but not protein kinase A, markedly decreased the PGE2-mediated edema formation. The i.pl. injection of PGE2 (3 nmol/paw) induced a significant activation of MAPKs, namely, JNK and p38, an effect that was largely prevented by the selective EP3 receptor antagonist L826266 (10 nmol/paw). Collectively, these findings indicate that edematogenic responses elicited by PGE2 are mediated by EP3 receptor activation, also involving the stimulation of PLC, PKC, and MAPKs pathways and the participation of TRPV1 and NK1 receptors. These results make a considerable contribution to our comprehension of the mechanisms involved in PGE2-mediated inflammatory responses in mice.
Assuntos
Dinoprostona , Edema/fisiopatologia , Receptores de Prostaglandina E/fisiologia , Actinas/metabolismo , Animais , Animais Recém-Nascidos , Western Blotting , Capsaicina , Proteínas Quinases Dependentes de AMP Cíclico/antagonistas & inibidores , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Edema/induzido quimicamente , Edema/metabolismo , Inibidores Enzimáticos/farmacologia , Pé/patologia , Proteínas de Ligação ao GTP/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Masculino , Camundongos , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Toxina Pertussis/farmacologia , Fosforilação/efeitos dos fármacos , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/metabolismo , Receptores de Prostaglandina E/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Fatty acids have been shown to regulate the expression of mRNA for both lipogenic and glycolytic enzymes in rat liver. The role of fatty acids in the regulation of carnitine palmitoyltransferase (CPT) I and II activity in tumour cells was investigated. The polyunsaturated fatty acids, gamma-linolenic and arachidonic acid, caused 60-70% inhibition of tumour cell CPT I activity and 45-50% inhibition of [14C]-palmitic acid oxidation to 14CO2. These effects were blocked by the cyclooxygenase inhibitor, indomethacin. Prostaglandins E1 and E2 caused marked inhibition of both CPT I and CPT II activity and inhibition of cell proliferation. Prostaglandin E2 production by tumour cells was increased in the presence of arachidonic acid and inhibited when indomethacin was present. The proliferation of the HT29 cell line was unaffected as was its CPT I and II activity by both fatty acids and prostaglandins. CPT I mRNA expression was not inhibited by fatty acids, indeed it increased-in the presence of arachidonic acid and prostaglandin E1. These results strongly suggest that polyunsaturated n-6 fatty acids are able, via prostaglandin products, to regulate the CPT activity of certain tumour cells. This may have a considerable impact on mitochondrial beta-oxidation and cellular metabolism of fatty acids, reflected in the marked inhibition of cell proliferation by these fatty acids.