RESUMO
PGD(2) is a key mediator of allergic inflammatory diseases that is mainly synthesized by mast cells, which constitutively express high levels of the terminal enzyme involved in PGD(2) synthesis, the hematopoietic PGD synthase (H-PGDS). In this study, we investigated whether eosinophils are also able to synthesize, and therefore, supply biologically active PGD(2). PGD(2) synthesis was evaluated within human blood eosinophils, in vitro differentiated mouse eosinophils, and eosinophils infiltrating inflammatory site of mouse allergic reaction. Biological function of eosinophil-derived PGD(2) was studied by employing inhibitors of synthesis and activity. Constitutive expression of H-PGDS was found within nonstimulated human circulating eosinophils. Acute stimulation of human eosinophils with A23187 (0.1-5 µM) evoked PGD(2) synthesis, which was located at the nuclear envelope and was inhibited by pretreatment with HQL-79 (10 µM), a specific H-PGDS inhibitor. Prestimulation of human eosinophils with arachidonic acid (10 µM) or human eotaxin (6 nM) also enhanced HQL-79-sensitive PGD(2) synthesis, which, by acting on membrane-expressed specific receptors (D prostanoid receptors 1 and 2), displayed an autocrine/paracrine ability to trigger leukotriene C(4) synthesis and lipid body biogenesis, hallmark events of eosinophil activation. In vitro differentiated mouse eosinophils also synthesized paracrine/autocrine active PGD(2) in response to arachidonic acid stimulation. In vivo, at late time point of the allergic reaction, infiltrating eosinophils found at the inflammatory site appeared as an auxiliary PGD(2)-synthesizing cell population. Our findings reveal that eosinophils are indeed able to synthesize and secrete PGD(2), hence representing during allergic inflammation an extra cell source of PGD(2), which functions as an autocrine signal for eosinophil activation.
Assuntos
Comunicação Autócrina/imunologia , Eosinófilos/imunologia , Eosinófilos/patologia , Hipersensibilidade/imunologia , Hipersensibilidade/patologia , Prostaglandina D2/fisiologia , Animais , Catálise , Eosinófilos/metabolismo , Feminino , Hematopoese/imunologia , Humanos , Hipersensibilidade/sangue , Inflamação/sangue , Inflamação/imunologia , Inflamação/patologia , Líquido Intracelular/imunologia , Líquido Intracelular/metabolismo , Oxirredutases Intramoleculares/biossíntese , Oxirredutases Intramoleculares/sangue , Lipocalinas/biossíntese , Lipocalinas/sangue , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Comunicação Parácrina/imunologia , Prostaglandina D2/biossíntese , Prostaglandina D2/sangue , Receptores Imunológicos/sangue , Receptores Imunológicos/fisiologia , Receptores de Prostaglandina/sangue , Receptores de Prostaglandina/fisiologiaRESUMO
BACKGROUND AND PURPOSE: The PPAR-γ agonist 15d-PGJ2 is a potent anti-inflammatory agent but only at high doses. To improve the efficiency of 15d-PGJ2, we used poly(D,L-lactide-co-glycolide) nanocapsules to encapsulate it, and function as a drug carrier system. The effects of these loaded nanocapsules (15d-PGJ2-NC) on inflammation induced by different stimuli were compared with those of free 15d-PGJ2. EXPERIMENTAL APPROACH: Mice were pretreated (s.c.) with either 15d-PGJ2-NC or unloaded 15d-PGJ2 (3, 10 or 30 µg·kg⻹), before induction of an inflammatory response by i.p. injection of either endotoxin (LPS), carrageenan (Cg) or mBSA (immune response). KEY RESULTS: The 15d-PGJ2-NC complex did not display changes in physico-chemical parameters or drug association efficiency over time, and was stable for up to 60 days of storage. Neutrophil migration induced by i.p. administration of LPS, Cg or mBSA was inhibited by 15d-PGJ2-NC, but not by unloaded 15d-PGJ2. In the Cg model, 15d-PGJ2-NC markedly inhibited serum levels of the pro-inflammatory cytokines TNF-α, IL-1ß and IL-12p70. Importantly, 15d-PGJ2-NC released high amounts of 15d-PGJ2, reaching a peak between 2 and 8 h after administration. 15d-PGJ 2 was detected in mouse serum after 24 h, indicating sustained release from the carrier. When the same concentration of unloaded 15d-PGJ2 was administered, only small amounts of 15d-PGJ2 were found in the serum after a few hours. CONCLUSIONS AND IMPLICATIONS: The present findings clearly indicate the potential of the novel anti-inflammatory 15d-PGJ2 carrier formulation, administered systemically. The formulation enables the use of a much smaller drug dose, and is significantly more effective compared with unloaded 15d-PGJ2.
Assuntos
Anti-Inflamatórios não Esteroides/administração & dosagem , Materiais Biocompatíveis , Inflamação/tratamento farmacológico , Ácido Láctico , Ácido Poliglicólico , Prostaglandina D2/análogos & derivados , Animais , Anti-Inflamatórios não Esteroides/sangue , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/uso terapêutico , Carragenina , Citocinas/análise , Portadores de Fármacos , Hemoglobinas/análise , Imunização , Lipopolissacarídeos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Nanocápsulas , Infiltração de Neutrófilos , Neutrófilos/imunologia , Tamanho da Partícula , Peritonite/tratamento farmacológico , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Prostaglandina D2/administração & dosagem , Prostaglandina D2/sangue , Prostaglandina D2/química , Prostaglandina D2/uso terapêutico , Soroalbumina Bovina/imunologiaRESUMO
INTRODUCTION: beta-trace protein or D2 prostaglandin synthase is a dual functional protein. Its role and clinical value in cerebrospinal fluid is under study. MATERIAL AND METHODS: Seventy four pediatric patients suffering from viral meningoencephalitis and 7 with bacterial meningoencephalitis were studied. Sera and cerebrospinal fluid samples were taken. Albumin and beta-trace protein were quantified by immunodiffusion and nephelometry respectively. RESULTS: Increased cerebrospinal fluid beta-trace protein levels in comparison with normal value were observed. Nevertheless such expected increment was no possible seen in bacterial meningoencephalitis. CONCLUSIONS: beta-trace protein may contribute with the etiological diagnosis in meningoencephalitis.