RESUMO
BACKGROUND: Perinatal maternal malnutrition is related to altered growth of tissues and organs. The nervous system development is very sensitive to environmental insults, being the hippocampus a vulnerable structure, in which altered number of neurons and granular cells has been observed. Moreover, glial cells are also affected, and increased expression of proinflammatory mediators has been observed. We studied the effect of Glucagon-like peptide-1 receptor (GLP-1R) agonists, liraglutide, which have very potent metabolic and neuroprotective effects, in order to ameliorate/prevent the glial alterations present in the hippocampus of the pups from mothers with food restriction during pregnancy and lactation (maternal perinatal food restriction-MPFR). METHODS: Pregnant Sprague-Dawley rats were randomly assigned to 50% food restriction (FR; n = 12) or ad libitum controls (CT, n = 12) groups at day of pregnancy 12 (GD12). From GD14 to parturition, pregnant FR and CT rats were treated with liraglutide (100 µg/kg) or vehicle. At postnatal day 21 and before weaning, 48 males and 45 females (CT and MPFR) were sacrificed. mRNA expression levels of interleukin-1ß (IL1ß), interleukin-6 (IL-6), nuclear factor-κß, major histocompatibility complex-II (MHCII), interleukin 10 (IL10), arginase 1 (Arg1), and transforming growth factor (TGFß) were assessed in the hippocampus by quantitative real-time polymerase chain reaction. Iba1 and GFAP-immunoreactivity were assessed by immunocytochemistry. RESULTS: The mRNA expression IL1ß, IL6, NF-κB, and MHCII increased in the hippocampus of male but not in female pups from MPFR. In addition, there was an increase in the percentage of GFAP and Iba1-immupositive cells in the dentate gyrus compared to controls, indicating an inflammatory response in the brain. On the other hand, liraglutide treatment prevented the neuroinflammatory process, promoting the production of anti-inflammatory molecules such as IL10, TGFß, and arginase 1, and decreasing the number and reactivity of microglial cells and astrocytes in the hippocampus of male pups. CONCLUSION: Therefore, the GLP-1 analog, liraglutide, emerges as neuroprotective drug that minimizes the harmful effects of maternal food restriction, decreasing neuroinflammation in the hippocampus in a very early stage.
Assuntos
Anti-Inflamatórios/uso terapêutico , Privação de Alimentos , Hipocampo/metabolismo , Liraglutida/uso terapêutico , Efeitos Tardios da Exposição Pré-Natal/patologia , Fatores Etários , Análise de Variância , Animais , Animais Recém-Nascidos , Peso Corporal/efeitos dos fármacos , Proteínas de Ligação ao Cálcio/metabolismo , Citocinas/metabolismo , Feminino , Idade Gestacional , Proteína Glial Fibrilar Ácida/metabolismo , Masculino , Proteínas dos Microfilamentos/metabolismo , Gravidez , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Fatores SexuaisRESUMO
Magnetic nanoparticles (NPs) have attracted great attention owing to their applications in the biomedical field. In the present work, maghemite (γFe2O3) NPs of 6.5 nm were prepared using a sonochemical method and used to prepare magnetic beads through silanization with 3-aminopropyltrimethoxysilane (APTS). Subsequently, amino groups in the resulting APTS-γFe2O3 beads were converted to carboxylic acid (CARB-γFe2O3) through the succinic anhydride reaction, as confirmed by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy and dynamic light scattering (DLS) measurements. The size of these beads was measured as 12 nm and their hydrodynamic diameter as 490 nm, using TEM analysis and DLS, respectively. The CARB-γFe2O3 beads were further functionalized by immobilizing rabbit antibodies on their surfaces; the immobilization was confirmed by flow cytometry and ionic strength. The samples were further characterized by Mössbauer spectroscopy and DC magnetization measurements. Studies on magnetic relaxivities showed that magnetic beads present great potential for application in MR imaging.
Assuntos
Anticorpos/metabolismo , Compostos Férricos/síntese química , Microesferas , Animais , Ácidos Carboxílicos/química , Difusão Dinâmica da Luz , Compostos Férricos/química , Fluorescência , Imageamento por Ressonância Magnética , Magnetismo , Nanopartículas/química , Nanopartículas/ultraestrutura , Tamanho da Partícula , Propilaminas/química , Coelhos , Silanos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Espectroscopia de Mossbauer , Eletricidade Estática , Vibração , Difração de Raios XRESUMO
In utero growth restriction and being born small for gestational age are risk factors for respiratory morbidity. IUGR (in utero growth retardation) is associated to overall reduction in lung weight, surfactant content and activity, impaired maturation of the alveolar type II cells, and decreased alveolar formation. The renin-angiotensin system (RAS) may be a key target underlying pathophysiological lung alterations. GLP-1 and agonists of its receptor modulate the expression levels of different components of RAS and also are very important for lung maturation and the production of surfactant proteins. The aim of this study was to elucidate the effects of IUGR induced by perinatal food restriction of the mother in the lung function of pups at early stages of life (PD21) and to determine if liraglutide had any effect during gestational period. Sprague-Dawley pregnant rats were randomly assigned to 50% food restriction (MPFR) or ad libitum control (CT) groups at day of pregnancy 12 (GD12). From GD14 to parturition, pregnant MPFR and CT rats were treated with liraglutide or vehicle. At postnatal day 21 and before weaning, 20 CT and 20 FR male pups were sacrificed and lungs were analyzed by RT-PCR. Liraglutide restored surfactant protein A (SP-A) mRNA expression in pup lungs from food-restricted mothers. Surfactant protein B (SP-B) mRNA expression is not affected by neither IUGR nor liraglutide treatment. Moreover, liraglutide modulated different elements of RAS, increasing angiotensin-converting enzyme 2 (ACE2) and MasR mRNA expression only in pups from food-restricted mothers (MPFR), despite food restriction had not any direct effect at this early stage. Liraglutide also increased endothelial nitric oxide synthase (eNOS) expression in MPFR lungs, reflecting the activation of MasR by angiotensin 1-7. In conclusion, liraglutide prevented the alteration in lung function induced by IUGR and promoted the positive effects of ACE2-Ang(1-7)-MasR in restoring lung function.
RESUMO
OBJECTIVES: The corticotrophin-releasing factor (CRF)/urocortin system is expressed in the adipose tissue of mammals, but its functional role in this tissue remains unknown. METHODS: Pharmacological manipulation of the activity of CRF receptors, CRF1 and CRF2, was performed in 3T3L1 white pre-adipocytes and T37i brown pre-adipocytes during in vitro differentiation. The expression of genes of the CRF/urocortin system and of markers of white and brown adipocytes was evaluated along with mitochondrial biogenesis and cellular oxygen consumption. Metabolic evaluation of corticosterone-deficient or supplemented Crhr1-null (Crhr1(-/-)) mice and their wild-type controls was performed along with gene expression analysis carried out in white (WAT) and brown (BAT) adipose tissues. RESULTS: Peptides of the CRF/urocortin system and their cognate receptors were expressed in both pre-adipocyte cell lines. In vitro pharmacological studies showed an inhibition of the expression of the CRF2 pathway by the constitutive activity of the CRF1 pathway. Pharmacological activation of CRF2 and, to a lesser extent, inhibition of CRF1 signaling induced molecular and functional changes indicating transdifferentiation of white pre-adipocytes and differentiation of brown pre-adipocytes. Crhr1(-/-) mice showed increased expression of CRF2 and its agonist Urocortin 2 in adipocytes that was associated to brown conversion of WAT and activation of BAT. Crhr1(-/-) mice were resistant to diet-induced obesity and glucose intolerance. Restoring physiological circulating corticosterone levels abrogated molecular changes in adipocytes and the favorable phenotype of Crhr1(-/-) mice. CONCLUSIONS: Our findings suggest the importance of the CRF2 pathway in the control of adipocyte plasticity. Increased CRF2 activity in adipocytes induces browning of WAT, differentiation of BAT and is associated with a favorable metabolic phenotype in mice lacking CRF1. Circulating corticosterone represses CRF2 activity in adipocytes and may thus regulate adipocyte physiology through the modulation of the local CRF/urocortin system. Targeting CRF receptor signaling specifically in the adipose tissue may represent a novel approach to tackle obesity.
Assuntos
Adipócitos Marrons/metabolismo , Adipócitos Brancos/metabolismo , Hormônio Liberador da Corticotropina/metabolismo , Obesidade/metabolismo , Pigmentos Biológicos/metabolismo , Receptores de Hormônio Liberador da Corticotropina/metabolismo , Urocortinas/metabolismo , Células 3T3-L1 , Animais , Regulação da Expressão Gênica , Imuno-Histoquímica , Camundongos , Obesidade/patologia , RNA Mensageiro/metabolismo , Transdução de SinaisRESUMO
Arginine-Vasopressin (AVP) may regulate the hypothalamic-pituitary-adrenal axis (HPA) and its effects on depressive responses. In a recent study, we demonstrated that Chronic Unpredictable Stress (CUS) depressive effects are enhanced by long-term ovariectomy (a model of post-menopause). In the present study, we investigated the effects of long-term ovariectomy and CUS on AVP expression in different subdivision of the paraventricular nucleus (PVN) of female mice. Both long-term ovariectomy and CUS affect AVP immunoreactivity in some of the PVN subnuclei of adult female mice. In particular, significant changes on AVP immunoreactivity were observed in magnocellular subdivisions, the paraventricular lateral magnocellular (PaLM) and the paraventricular medial magnocellular (PaMM), the 2 subnuclei projecting to the neurohypophysis for the hormonal regulation of body homeostasis. AVP immunoreactivity was decreased in the PaLM by both the long-term deprivation of ovarian hormones and the CUS. In contrast, AVP immunoreactivity was increased in the PaMM by CUS, whereas it was decreased by ovariectomy. Therefore, present results suggest morphological and functional differences among the PVN's subnuclei and complex interactions among CUS, gonadal hormones and AVP immunoreactivity.
Assuntos
Arginina Vasopressina/metabolismo , Hormônios Gonadais/deficiência , Núcleo Hipotalâmico Paraventricular/metabolismo , Núcleo Hipotalâmico Paraventricular/patologia , Estresse Psicológico/metabolismo , Estresse Psicológico/patologia , Animais , Doença Crônica , Corticosterona/sangue , Feminino , Imuno-Histoquímica , Camundongos Endogâmicos C57BL , Ovariectomia , Fotomicrografia , IncertezaRESUMO
Neuroinflammation comprises a feature of many neurological disorders that is accompanied by the activation of glial cells and the release of pro-inflammatory cytokines and chemokines. Such activation is a normal response oriented to protect neural tissue and it is mainly regulated by microglia and astroglia. However, excessive and chronic activation of glia may lead to neurotoxicity and may be harmful for neural tissue. The ovarian hormone oestradiol exerts protective actions in the central nervous system that, at least in part, are mediated by a reduction of reactive gliosis. Several selective oestrogen receptor modulators may also exert neuroprotective effects by controlling glial inflammatory responses. Thus, tamoxifen and raloxifene decrease the inflammatory response caused by lipopolysaccharide, a bacterial endotoxin, in mouse and rat microglia cells in vitro. Tamoxifen and raloxifene are also able to reduce microglia activation in the brain of male and female rats in vivo after the peripheral administration of lipopolysaccharide. In addition, tamoxifen decreases the microglia inflammatory response induced by irradiation. Furthermore, treatment with tamoxifen and raloxifene resulted in a significant reduction of the number of reactive astrocytes in the hippocampus of young, middle-aged and older female rats after a stab wound injury. Tamoxifen, raloxifene and the new selective oestrogen receptor modulators ospemifene and bazedoxifene decrease the expression and release of interleukine-6 and interferon-γ inducible protein-10 in cultured astrocytes exposed to lipopolysaccharide. Ospemifene and bazedoxifene exert anti-inflammatory effects in astrocytes by a mechanism involving classical oestrogen receptors and the inhibition of nuclear factor-kappa B p65 transactivation. These data suggest that oestrogenic compounds are candidates to counteract brain inflammation under neurodegenerative conditions by targeting the production and release of pro-inflammatory molecules by glial cells.
Assuntos
Encefalite/imunologia , Neuroglia/efeitos dos fármacos , Cloridrato de Raloxifeno/farmacologia , Moduladores Seletivos de Receptor Estrogênico/farmacologia , Tamoxifeno/farmacologia , Animais , Anti-Inflamatórios/imunologia , Anti-Inflamatórios/farmacologia , Neuroglia/imunologia , RatosAssuntos
Alopecia em Áreas/induzido quimicamente , Anticorpos Monoclonais/efeitos adversos , Antirreumáticos/efeitos adversos , Artrite Reumatoide/tratamento farmacológico , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Adalimumab , Adulto , Alopecia em Áreas/diagnóstico , Alopecia em Áreas/imunologia , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais Humanizados , Antirreumáticos/administração & dosagem , Artrite Reumatoide/complicações , Feminino , HumanosRESUMO
The actions of corticotropin-releasing factor (CRF) and related peptides are mediated by two receptors (CRF(1) and CRF(2)). The respective role of each subtype in the control of food intake remains poorly known. In the present study, we examined the quantity and microstructure of ingestive behavior of knockout (KO) mice lacking CRF(2) receptors and their wild-type (WT) littermates. Under basal conditions, CRF(2) KO mice showed increased nocturnal food intake, evident as an increased zenith in circadian cosinor analysis of food intake. Microstructure analysis revealed that this greater food intake reflected increased meal size, rather than meal frequency, suggesting a decreased satiating value of food. Following acute restraint stress, CRF(2) KO mice showed an intact immediate anorectic response with increased latency to eat and decreased meal size. However, CRF(2) deletion abolished the prolonged phase of restraint-induced anorexia. CRF(2) KO mice did not differ from WT controls in feeding responses to food deprivation or injection of ghrelin receptor agonists. Independent of genotype, food deprivation increased food intake, with dramatic changes in meal size, meal frequency, water : food ratio and eating rate. Acyl-ghrelin or BIM-28131, a potent ghrelin analog, dose-dependently stimulated food intake by increasing meal size (ghrelin, BIM-28131) and meal number (BIM-28131), while slowing the average eating rate (BIM-28131) similarly in WT and KO mice. These results suggest that the CRF(2) receptor is involved in the control of meal size during the active phase of eating and following acute exposure to stress.
Assuntos
Ingestão de Alimentos/fisiologia , Comportamento Alimentar/psicologia , Receptores de Hormônio Liberador da Corticotropina/fisiologia , Animais , Comportamento Animal , Relação Dose-Resposta a Droga , Ingestão de Líquidos/fisiologia , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Alimentos/genética , Comportamento Alimentar/efeitos dos fármacos , Privação de Alimentos/fisiologia , Grelina/agonistas , Grelina/análogos & derivados , Grelina/farmacologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Periodicidade , Receptores de Hormônio Liberador da Corticotropina/deficiência , Restrição Física/métodos , Fatores de TempoRESUMO
GH secretion is markedly altered in diabetes mellitus (DM) in both rats and humans, albeit in opposite directions. In the rat, diabetes suppresses pulsatile GH secretion, especially high amplitude pulses, and decreases GH responses to secretagogue, depending inversely on severity of metabolic alteration. In the present study, we wanted to address the GH responses to GHRH and low doses of ghrelin in a streptozotocin (STZ) model of diabetes characterized by the delayed onset of the metabolic alterations. We have shown that the administration of high doses of STZ (90 mg/kg in 0.01 M solution of chloride-sodium, ip) to five-day-old pups (n5-STZ) can induce the appearance of a characteristic diabetic syndrome in adult age, the diabetic triad, with elevated plasma glucose levels: polyuria, polydipsia, hyperphagia, and reduced body weight gain. At the age of 3 months, in these n5-STZ male and female rats the GH responses to GHRH (1 microg/kg) and GHRH combined with ghrelin (1+3 microg/kg) had diminished both in punctual times and in the area under the curve (AUC). However, the combined administration of GHRH and ghrelin, being the more potent stimulus, elicited a synergistic GH response. Thus, male and female rats with delayed onset diabetes displayed an altered GH response to GHRH, although the combined administration of GHRH and ghrelin was able to restore the GH secretion with a synergistic effect.
Assuntos
Diabetes Mellitus Experimental/induzido quimicamente , Hormônio Liberador de Hormônio do Crescimento/farmacologia , Hormônio do Crescimento/metabolismo , Hormônios Peptídicos/farmacologia , Idade de Início , Animais , Animais Recém-Nascidos , Peso Corporal/efeitos dos fármacos , Ingestão de Líquidos/efeitos dos fármacos , Ingestão de Alimentos/efeitos dos fármacos , Feminino , Grelina , Teste de Tolerância a Glucose , Masculino , Ratos , Ratos Sprague-Dawley , Fatores de TempoRESUMO
Using pharmacological tools, a role for opioid receptors in the regulation of food intake has been documented. However, the involvement of specific receptor subtypes remains questionable, and little information is available regarding a role for opioid receptors in energy metabolism. Using adult male mice lacking the mu-opioid receptor (MOR) gene (MOR-/-), we show that the MOR is not essential for the maintenance of normal levels of ad libitum food intake but does modulate the efficiency of energy storage during high-fat diets through the regulation of energy partitioning. When fed a regular diet, MOR-/- mice displayed only subtle alterations in energy homeostasis, suggesting a relative overuse of fat as a fuel source in the fed state. When fed a high-fat diet, MOR-/- mice were resistant to obesity and impaired glucose tolerance, despite having similar energy intake to wild-type mice. This resistance to obesity was associated with a strong induction of the expression of key mitochondrial enzymes involved in fatty acid oxidation within skeletal muscle. This metabolic role of the MOR, which is consistent with the properties of a "thrifty gene," suggests that the MOR pathway is a potential target for pharmacological intervention in the treatment of obesity associated with the intake of fatty diets.