RESUMO
A close link between intrauterine growth restriction and development of chronic adult diseases such as obesity, diabetes, and hypertension has been established both in humans and animals. Modification of growth velocity during the early postnatal period (i.e., lactation) may also sensitize to the development of metabolic syndrome in adulthood. This suggests that milk composition may have long-lasting programming/deprogramming metabolic effects in the offspring. We therefore assess the effects of maternal perinatal denutrition on breast milk composition in a food-restricted 50% (FR50) rat model. Monosaccharides and fatty acids were characterized by gas chromatography, and proteins were profiled by surface-enhanced laser desorption/ionization-time-of-flight analysis in milk samples from FR50 and control rat dams. Milk analysis of FR50 rats demonstrated that maternal undernutrition decreases lactose concentration and modulates lipid profile at postnatal day 10 by increasing the unsaturated fatty acids/saturated fatty acids and diminishes serotransferrin levels at postnatal day 21. Our data indicate that maternal perinatal undernutrition modifies milk composition both quantitatively and qualitatively. These modifications by maternal nutrition open new perspectives to identify molecules that could be used in artificial milk to protect from the subsequent development of metabolic diseases.
Assuntos
Lactose/metabolismo , Desnutrição/metabolismo , Fenômenos Fisiológicos da Nutrição Materna , Doenças Metabólicas/etiologia , Leite/metabolismo , Complicações na Gravidez/metabolismo , Transferrina/metabolismo , Animais , Animais Lactentes , Feminino , Lactação/metabolismo , Masculino , Parto/metabolismo , Gravidez , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Ratos , Ratos Wistar , Fatores de RiscoRESUMO
Epidemiological studies initially suggested that maternal undernutrition leading to low birth weight may predispose for long-lasting energy balance disorders. High birth weight due to maternal obesity or diabetes, inappropriate early postnatal nutrition, and rapid catch-up growth, may also sensitize to increased risk of obesity. As stated by the Developmental Origin of Health and Disease concept, the perinatal perturbation of fetus/neonate nutrient supply might be a crucial determinant of individual programming of body weight set-point. The hypothalamic melanocortin system composed of the melanocortin receptor 4, its agonist α-melanin-stimulating hormone (α-MSH), and its antagonist agouti-related protein (AgRP) is considered as the main central anorexigenic pathway controlling energy homeostasis. Studies in numerous animal models demonstrated that this system is a prime target of developmental programming by maternal nutritional manipulation. In rodents, the perinatal period of life corresponds largely to the period of brain maturation (i. e., melanocortin neuronal differentiation and development of their neural projections). In contrast, these phenomena essentially take place before birth in bigger mammals. Despite these different developmental time windows, altricial and precocial species share several common offspring programming mechanisms. Offspring from malnourished dams present a hypothalamic melanocortin system with a series of alterations: impaired neurogenesis and neuronal functionality, disorganization of feeding pathways, modified glucose sensing, and leptin/insulin resistance. Overall, these alterations may account for the long-lasting dysregulation of energy balance and obesity. Following maternal malnutrition, hormonal and epigenetic mechanisms might be responsible for melanocortin system programming in offspring.
Assuntos
Metabolismo Energético , Hipotálamo , Resistência à Insulina , Melanocortinas/metabolismo , Obesidade , Receptor Tipo 4 de Melanocortina/metabolismo , Animais , Macrossomia Fetal/etiologia , Macrossomia Fetal/metabolismo , Macrossomia Fetal/patologia , Macrossomia Fetal/fisiopatologia , Humanos , Hipotálamo/metabolismo , Hipotálamo/patologia , Hipotálamo/fisiopatologia , Desnutrição/metabolismo , Desnutrição/patologia , Desnutrição/fisiopatologia , Obesidade/etiologia , Obesidade/metabolismo , Obesidade/patologia , Obesidade/fisiopatologia , alfa-MSH/metabolismoRESUMO
Proopiomelanocortin is a polypeptide precursor molecule, the processing of which generates ACTH, beta-endorphin, the beta- and gamma-lipotropins, the joining peptide, and the NH2-terminal fragment. Anterior pituitary corticotrophs are the major site of proopiomelanocortin gene expression in man and the predominant, if not sole source of circulating ACTH. Recent data have established that proopiomelanocortin gene expression also occurs in various normal nonpituitary tissues, one of the best studied being the testis. In this latter organ the dominant gene products are short transcripts of approximately 800 nucleotides, which lack the first two exons of the gene and cannot encode a complete proopiomelanocortin molecule. In this report we show that the mode of proopiomelanocortin gene expression is occasionally modified in human Leydig cell tumors: a 1,200-nucleotide mRNA species identical to that in the pituitary is produced. It results from the usual (pituitary) start site of transcription and thus can encode the complete proopiomelanocortin molecule. In two out of six tumors, large amounts of the 1,200-nucleotide transcript led to a dramatic increase of approximately 1,000-fold in proopiomelanocortin peptide concentrations as compared with the normal and peritumoral testis. Proopiomelanocortin processing in these tumors generates various peptide fragments including ACTH. These results may help to understand the mechanism of proopiomelanocortin expression in nonpituitary tumors and have implications for the more general phenomenon of ectopic hormone secretion.
Assuntos
Regulação Neoplásica da Expressão Gênica , Tumor de Células de Leydig/genética , Pró-Opiomelanocortina/genética , Northern Blotting , Sondas de DNA , Humanos , Masculino , Peso Molecular , Pró-Opiomelanocortina/metabolismo , Processamento de Proteína Pós-Traducional , RNA Mensageiro/genética , RNA Neoplásico/genética , Testículo/fisiologia , Transcrição GênicaRESUMO
Based on the Developmental Origin of Health and Disease concept, maternal undernutrition has been shown to sensitize adult offspring to metabolic pathologies such as obesity. Using a model of maternal 70% food restriction in pregnant female rats throughout gestation (called FR30), we previously reported that obesity-prone adult male rat offspring displayed hyperleptinemia with modifications in leptin and leptin receptor messenger RNA (mRNA) levels in white adipose tissue (WAT). Apelin is a member of the adipokine family that regulates various aspects of energy metabolism and WAT functionality. We investigated whether apelin and its receptor APJ could be a target of maternal undernutrition. Adult male rat offspring from FR30 dams showed increased plasma apelin levels and apelin gene expression in WAT. Post-weaning high-fat diet led to marked increase in APJ mRNA and protein levels in offspring's WAT. We demonstrate that maternal undernutrition and post-weaning diet have long-term consequences on the apelinergic system of adult male rat offspring.
Assuntos
Tecido Adiposo/metabolismo , Receptores de Apelina/metabolismo , Apelina/metabolismo , Desnutrição/fisiopatologia , Tecido Adiposo/patologia , Animais , Peso Corporal , Metabolismo Energético , Feminino , Leptina/metabolismo , Masculino , Gravidez , RatosRESUMO
During the course of evolution invertebrates and vertebrates have maintained common signaling molecules, such as neuropeptides. For example, complete hormonal-enzymatic systems for the biosynthesis of opioid peptides have been found in both the CNS and immune systems of these animals. These signaling molecules have been found in the blood circulation and act as immunomodulators. In vertebrates, release of the signaling molecules occurs during stress (cognitive or pathogens), which triggers the hypothalamo-hypophysial-adrenal axis. Similarly, these neuropeptides are used as messengers to initiate and stimulate the innate immune response in invertebrates. Thus, the crosstalk between nervous and immune systems has an ancient evolutionary origin and the messengers used have been conserved during the course of evolution reflecting their vital importance.
Assuntos
Sistema Imunitário/fisiologia , Fenômenos Fisiológicos do Sistema Nervoso , Animais , Encefalinas/sangue , Encefalinas/fisiologia , Hemolinfa/metabolismo , Humanos , Neuroimunomodulação/fisiologiaRESUMO
In annelids, it has been established that arginine-vasopressin (AVP)/oxytocin (OT) superfamily peptides are involved in the maintenance of water and electrolyte homeostasis as well as reproduction. At present, there is little information on their receptors. In this study, we report the characterization of a 1.7 kb cDNA for an AVP-related receptor from the leech Theromyzon tessulatum. The open reading frame encodes a 435-aminoacid transmembrane protein that displays seven segments of hydrophobic amino acids, typical of G-protein-coupled receptors. The overall predicted protein exhibits about 30% amino-acid identities to other invertebrate, as well as vertebrate, AVP/OT receptor family members, and displays conserved characteristic features belonging to the AVP/OT receptor superfamily. RT-PCR expression experiments showed that mRNA is expressed in the genital tract, the ovary and the brain. The receptor expression is stage specific, showing a weak expression after the two first blood meals, increasing dramatically after the last blood meal during the period of sexual maturation and disappearing after egg laying. Thus, the leech AVP-related receptor may mediate reproductive functions. When expressed in COS-7 cells, the receptor binds ligands with the following rank order of potency: AVP= Arg-vasotocin >Arg-conopressin >mesotocin = OT = Lys-conopressin=isotocin>annetocin. This shows an AVP-like pharmacological profile. The transfected receptor mediates AVP-induced accumulation of inositol phosphates, indicating that the leech AVP-related receptor is functional. This study describes the characterization of a novel AVP/OT superfamily receptor in annelids, which are considered the most distant group of coelomate metazoans possessing a functional AVP/OT-related endocrine system.
Assuntos
Sanguessugas/metabolismo , Receptores de Vasopressinas/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Células COS , Galinhas , Feminino , Humanos , Lymnaea , Masculino , Dados de Sequência Molecular , Octopodiformes , Ligação Proteica , Ensaio Radioligante , Receptores de Vasopressinas/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Transfecção/métodos , Vasopressinas/metabolismoRESUMO
The tumor cell line beta TC3 has been established from insulinomas derived from transgenic mice carrying a hybrid insulin promoter-simian virus-40 tumor antigen gene. The beta TC3 cells express high steady state levels of proinsulin messenger RNA (mRNA). In this same cell line, we describe in the present study high expression levels of prodynorphin (pro-Dyn) mRNA and its derived peptides. By Northern blot analysis, the screening of 23 cell lines of endocrine (n = 10) and of nonendocrine (n = 13) origin revealed the presence of high levels of the 2.6-kilobase pro-Dyn transcript only in beta TC3 cells. The beta TC3 cells expressed levels of pro-Dyn mRNA comparable to those in rat tissues expressing pro-Dyn. Chromatographic and radioimmunological studies showed that pro-Dyn mRNA was translated and fully processed into opioid peptides with leucine-enkephalin (Leu-Enk)-extended sequences [dynorphin-A-(1-8), dynorphin-B-(1-13), and alpha-neo-endorphin]. The expression of the prohormone convertases was also examined in beta TC3 cells by Northern blot analysis. In addition to the ubiquitously expressed furin, beta TC3 cells have abundant levels of prohormone convertase-1 (PC1) and PC2 mRNAs, but undetectable levels of PACE4 or PC5 mRNAs. Incubation of beta TC3 cells with 8-bromo-cAMP for 24 h stimulated 3-fold both the pro-Dyn mRNA levels and the secretion of opioid peptides. In contrast to pro-Dyn mRNA, furin, PC1, and PC2 mRNA levels were not affected by 8-bromo-cAMP. The beta TC3 cells constitute a unique model to elucidate the biosynthetic pathway of pro-Dyn processing, to identify the proteolytic enzymes responsible for the production of pro-Dyn end products, and to assess the potential role of opioid peptides in the regulation of pancreatic function.
Assuntos
Encefalinas/genética , Encefalinas/metabolismo , Insulinoma/metabolismo , Neoplasias Pancreáticas/metabolismo , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo , Processamento de Proteína Pós-Traducional , RNA Mensageiro/metabolismo , 8-Bromo Monofosfato de Adenosina Cíclica/farmacologia , Animais , Encefalinas/química , Furina , Insulinoma/patologia , Camundongos , Neoplasias Pancreáticas/patologia , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Precursores de Proteínas/química , Radioimunoensaio , Subtilisinas/genética , Células Tumorais CultivadasRESUMO
POMC processing is frequently altered in ACTH-secreting nonpituitary tumors in which intermediate lobe-like peptides such as corticotropin-like intermediate lobe peptide (CLIP) are occasionally generated. In rodent pituitaries, the exclusive presence of prohormone convertase PC2 in the melanotrophs of the intermediate lobe is responsible for the specific conversion of ACTH to alpha MSH and CLIP, by contrast with corticotrophs of the anterior lobe, which do not contain PC2 and, therefore, only produce ACTH. The goal of our study was to look for PC2 expression in ACTH-secreting nonpituitary tumors in man. Using Northern blot analysis, PC2 transcripts were detected in five nonpituitary tumors that contained large proportions of CLIP (from 40-95% of the total C-terminal immunoreactive ACTH). A predominant PC2 messenger ribonucleic acid migrated with an apparent mol wt of 5 kilobases, and a minor signal at 3 kilobases was also detected. No PC2 messenger ribonucleic acid could be detected in the small cell carcinoma of the lung-derived DMS-79 human cell line, which produces unprocessed POMC, or in three pituitary tumors responsible for Cushing's disease or Nelson's syndrome, which produced intact ACTH, but no CLIP. These data strongly suggest that, as in rodents, PC2 is responsible for the production of smaller POMC end products, such as CLIP, frequently observed in ACTH-secreting nonpituitary tumors in man.
Assuntos
Hormônio Adrenocorticotrópico/análise , Hormônio Adrenocorticotrópico/metabolismo , Neoplasias Brônquicas/química , Neoplasias Brônquicas/metabolismo , Tumor Carcinoide/química , Tumor Carcinoide/metabolismo , Fragmentos de Peptídeos/análise , Neoplasias Hipofisárias/química , Neoplasias Hipofisárias/metabolismo , Subtilisinas/análise , Neoplasias do Timo/química , Neoplasias do Timo/metabolismo , Hormônio Adrenocorticotrópico/genética , Hormônio Adrenocorticotrópico/fisiologia , Sequência de Bases , Neoplasias Brônquicas/patologia , Tumor Carcinoide/patologia , Carcinoma de Células Pequenas/química , Carcinoma de Células Pequenas/genética , Carcinoma de Células Pequenas/patologia , Peptídeo da Parte Intermédia da Adeno-Hipófise Semelhante à Corticotropina , DNA de Neoplasias/análise , DNA de Neoplasias/genética , Humanos , Neoplasias Pulmonares/química , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Dados de Sequência Molecular , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/fisiologia , Neoplasias Hipofisárias/patologia , Pró-Proteína Convertase 2 , Subtilisinas/genética , Subtilisinas/fisiologia , Neoplasias do Timo/patologia , Células Tumorais CultivadasRESUMO
Proopiomelanocortin (POMC) gene expression is not restricted to the pituitary corticotroph cell, but also takes place in many normal and tumoral nonpituitary tissues. In contrast, the ectopic ACTH syndrome is a rare event. Because it is most often associated with lung tumors, we specifically studied this tissue, analyzing the different forms of POMC RNAs in normal specimens as well as in various types of tumors. The endocrine nature of the tumors was assessed by both histological examination and measurements of secretogranin-I fragments in the tissue extracts. POMC RNA was first detected by Northern blot analysis; its absolute amounts and its various molecular forms were more precisely quantified and discriminated by S1 mapping studies using a single stranded DNA probe located at the 5' end of exon 3. In five bronchial carcinoid tumors associated with the ectopic ACTH syndrome, a highly predominant, if not single, POMC RNA identical to the 1200-nucleotide (nt) pituitary message was present, the high amounts of which were correlated with those of POMC peptides in the same tissues. In five bronchial carcinoid tumors not associated with the ectopic ACTH syndrome, the same message was detected (four of five), with a second, often predominant, short RNA of about 800 nt (five of five), and the overall amounts of POMC RNAs were low. Similar patterns of POMC RNAs were observed in squamous cell tumors, adenocarcinomas, and normal lung, where the short 800-nt RNA tended to be predominant. These results show that POMC gene expression can be demonstrated in normal lung tissue and in all types of lung tumors. The ectopic ACTH syndrome only occurs with tumors capable of generating high amounts of the pituitary-like message, a phenomenon that seems to be restricted to an occasional tumor with features of neuroendocrine differentiation.
Assuntos
Tumor Carcinoide/genética , Neoplasias Pulmonares/genética , Pulmão/fisiopatologia , Pró-Opiomelanocortina/genética , Tumor Carcinoide/cirurgia , Sondas de DNA , Éxons , Expressão Gênica , Pulmão/fisiologia , Neoplasias Pulmonares/cirurgia , Hibridização de Ácido Nucleico , Sondas de Oligonucleotídeos , Pró-Opiomelanocortina/análise , RNA Neoplásico/genética , RNA Neoplásico/isolamento & purificação , Radioimunoensaio , Valores de Referência , Mapeamento por Restrição , Transcrição GênicaRESUMO
Prohormone convertases (PCs) are calcium-dependent serine endoproteases of the subtilisin/kexin family that play a key role in the posttranslational processing of precursors for biologically active peptides. In this study, we have characterized the cDNA encoding PC1 in the European green frog Rana ridibunda. A frog brain cDNA library was screened by using a heterologous probe at low stringency, and a 2.3-kb cDNA clone encoding PC1 was isolated. This cDNA encodes a 736-residue protein with a 26-amino-acid signal peptide. Comparative structural analysis revealed that frog PC1 exhibits a high degree of amino acid identity with its mammalian counterparts, in particular in the subtilisin-like catalytic domain. Northern blot analysis resolved two major transcripts of 3.0 kb and 5.0 kb that were expressed differentially in the brain and pituitary. In situ hybridization studies showed that, in the frog brain, the highest densities of PC1 mRNA are present in the amygdala, the hypothalamus, and the anterior preoptic area. High concentrations of PC1 mRNA also were found in the pars distalis and pars intermedia of the pituitary, whereas the pars nervosa was devoid of hybridization signal. The wide distribution of PC1 mRNA in the brain and pituitary suggests that, in frog, PC1 is involved in the processing of a number of hormone and neuropeptide precursors.
Assuntos
Ácido Aspártico Endopeptidases/genética , DNA Complementar/genética , RNA Mensageiro/genética , Rana ridibunda/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Encéfalo/enzimologia , Domínio Catalítico , Clonagem Molecular , Código Genético , Hibridização In Situ , Masculino , Dados de Sequência Molecular , Pró-Proteína Convertases , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
There is growing evidence that prenatal adversities could be implicated in foetal programming of adult chronic diseases. Since maternal stress is known to disturb the foetal glucocorticoid environment, we examined the consequences of prenatal stress on foetal growth, on glucose-insulin metabolism and on feeding behaviour in the aged male rat. In foetuses at term, maternal stress reduced body, adrenal and pancreas weight as well as plasma corticosterone and glucose levels. In aged male rats (24 months of age), prenatal stress induced hyperglycaemia and glucose intolerance and decreased basal leptin levels. Moreover, after a fasting period, they showed an increased food intake. These data suggest that maternal stress induces a long-lasting disturbance in feeding behaviour and dysfunctions related to type 2 diabetes mellitus. This programming could be linked to the early restricted foetal growth and to the adverse glucocorticoid environment in utero.
Assuntos
Envelhecimento/fisiologia , Comportamento Alimentar , Retardo do Crescimento Fetal/etiologia , Intolerância à Glucose/etiologia , Efeitos Tardios da Exposição Pré-Natal , Estresse Psicológico/complicações , Glândulas Suprarrenais/anatomia & histologia , Animais , Peso ao Nascer , Glicemia/análise , Corticosterona/sangue , Feminino , Leptina/sangue , Masculino , Tamanho do Órgão , Pâncreas/anatomia & histologia , Gravidez , Ratos , Ratos Sprague-DawleyRESUMO
Many peptides contribute to the heterogeneity of immunoreactive adrenocorticotropin (ACTH) in man. The use of a radioimmunoassay (RIA) specifically directed against the C-terminal end of ACTH allowed us to study precisely the following four peptides: ACTH itself, corticotropin-like intermediary lobe peptide (CLIP) or ACTH (18-39) and their phosphorylated forms on Ser31. We have set up a high-performance liquid chromatography system that separates these four molecules in a single run, to establish their relative distributions in tumors responsible for Cushing's disease or for the ectopic ACTH syndrome, and to evaluate the possible interference of phospho-Ser31 on various RIA or immunoradiometric assay (IRMA) recognition systems for ACTH. In this system, alkaline phosphatase treatment shifted the retention time of the phosphorylated peptides to that of their non-phosphorylated counterparts. In three tumors responsible for the ectopic ACTH syndrome, CLIP peptides were predominant in two and phosphorylated molecules represented between 22% and 50% of immunoreactive materials. In five pituitary tumors responsible for Cushing's disease, ACTH peptides were predominant and the phosphorylated molecules varied between 35% and 75% in four of them. In the same tumor the ratios of phosphorylated to non-phosphorylated CLIP or ACTH were identical. The presence of phospho-Ser31 did not affect the recognition ability of two mid-ACTH and two C-terminal ACTH RIAs, nor of the ACTH IRMA (Allegro, Nichols).
Assuntos
Adenoma/química , Neoplasias das Glândulas Suprarrenais/química , Hormônio Adrenocorticotrópico/análise , Hormônio Adrenocorticotrópico/metabolismo , Fragmentos de Peptídeos/análise , Fragmentos de Peptídeos/metabolismo , Feocromocitoma/química , Neoplasias Hipofisárias/química , Adenoma/metabolismo , Adenoma/patologia , Neoplasias das Glândulas Suprarrenais/metabolismo , Neoplasias das Glândulas Suprarrenais/patologia , Cromatografia Líquida de Alta Pressão , Peptídeo da Parte Intermédia da Adeno-Hipófise Semelhante à Corticotropina , Humanos , Ensaio Imunorradiométrico , Feocromocitoma/metabolismo , Feocromocitoma/patologia , Fosforilação , Neoplasias Hipofisárias/metabolismo , Neoplasias Hipofisárias/patologia , RadioimunoensaioRESUMO
A number of precursors for neuropeptides have recently been cloned in amphibians, but little is known concerning the endoproteases responsible for the processing of these precursors. Here we report on the molecular cloning of the cDNA encoding the proprotein convertase PC2 and the distribution of the corresponding mRNA in the European green frog Rana ridibunda. The full cDNA structure (2125 bp) was obtained from the analysis of the PCR products combined with the sequence from a clone isolated from a frog pituitary cDNA library. The deduced amino acid sequence revealed that frog PC2 comprises 636 amino acid residues including a 22-residue signal peptide. RT-PCR analysis showed that PC2 is expressed not only in the brain and pituitary but also in various peripheral organs including the pancreas, stomach, intestine, liver, kidney and testis. In situ hybridization histochemistry revealed that, in the central nervous system, PC2 mRNA is widely distributed, the highest concentrations being found in the pallium, the anterior preoptic area, the hypothalamus and the medial amygdala. High levels of PC2 mRNA were also detected in the intermediate lobe of the pituitary. The overall distribution of PC2 mRNA in the frog brain is consistent with its involvement in the processing of a number of neuropeptide and hormone precursors.
Assuntos
Encéfalo/enzimologia , Subtilisinas/genética , Animais , Elementos Antissenso (Genética) , Sequência de Bases , Clonagem Molecular , DNA Complementar/análise , Hibridização In Situ , Masculino , Dados de Sequência Molecular , Neuropeptídeos/metabolismo , Hipófise/química , Pró-Proteína Convertase 2 , RNA Mensageiro/análise , Rana ridibunda , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência de AminoácidosRESUMO
First isolated in porcine pituitary glands the protein 7B2 subsequently proved to be a specific biochemical marker of the secretory granules. Likewise 7B2 was detected in almost all normal and tumoral endocrine tissues. Unexpectedly, several authors failed to demonstrate its presence in rat and human adrenocorticotrophin (ACTH)-secreting cells. In order to definitely establish whether this cell type also produces 7B2 we chose the mouse pituitary corticotroph tumour cell line AtT-20 as a model. Serial dilutions of the mouse culture medium generated displacement curves parallel to that of the standard in a specific 7B2 RIA directed against the human 7B2(23-39) fragment. Under basal secretory conditions immunoreactive 7B2 accumulated in the culture medium in parallel with proopiomelanocortin (POMC) and its fragments N-terminal-joining peptide (NT-JP), joining peptide (JP), beta-lipotropin (beta-LPH), and beta-endorphin (beta-end), although at a much lower (approximately 100-fold) molar concentration. As expected mouse corticotroph cells responded to the stimulatory action of cyclic AMP (3.5 mM) with a preferential increase in the release of POMC end-products, JP and beta-end, which was accompanied by a parallel increase in immunoreactive 7B2 release.
RESUMO
Undernutrition exposure during the perinatal period reduces the growth kinetic of the offspring and sensitizes it to the development of chronic adult metabolic diseases both in animals and in humans. Previous studies have demonstrated that a 50% maternal food restriction performed during the last week of gestation and during lactation has both short- and long-term consequences in the male rat offspring. Pups from undernourished mothers present a decreased intrauterine (IUGR) and extrauterine growth restriction. This is associated with a drastic reduction in their leptin plasma levels during lactation, and exhibit programming of their stress neuroendocrine systems (corticotroph axis and sympatho-adrenal system) in adulthood. In this study, we report that perinatally undernourished 6-month-old adult animals demonstrated increased leptinemia (at PND200), blood pressure (at PND180), food intake (from PND28 to PND168), locomotor activity (PND187) and altered regulation of glycemia (PND193). Cross-fostering experiments indicate that these alterations were prevented in IUGR offspring nursed by control mothers during lactation. Interestingly, the nutritional status of mothers during lactation (ad libitum feeding v. undernutrition) dictates the leptin plasma levels in pups, consistent with decreased leptin concentration in the milk of mothers subjected to perinatal undernutrition. As it has been reported that postnatal leptin levels in rodent neonates may have long-term metabolic consequences, restoration of plasma leptin levels in pups during lactation may contribute to the beneficial effects of cross-fostering IUGR offspring to control mothers. Collectively, our data suggest that modification of milk components may offer new therapeutic perspectives to prevent the programming of adult diseases in offspring from perinatally undernourished mothers.
Assuntos
Lactação , Fenômenos Fisiológicos da Nutrição Pré-Natal , Aldosterona/sangue , Animais , Animais Recém-Nascidos , Fator Natriurético Atrial/metabolismo , Pressão Sanguínea , Composição Corporal , Feminino , Glucose/metabolismo , Frequência Cardíaca , Leptina/sangue , Masculino , Desnutrição/complicações , Gravidez , Ratos Wistar , Fatores de Tempo , Vasopressinas/sangueRESUMO
Genetic variants in the FTO (fat mass- and obesity-associated) gene have the highest association of all obesity-associated genes. Its placental expression was shown to relate to birth weight, suggesting that it may participate in the control of fetal weight gain. To gain more insight into the implication of FTO in fetal growth, we measured its placental expression in samples including extremes of abnormal fetal growth, such as after intrauterine growth restriction (IUGR) or macrosomia in both rats and humans. In rats, fetal growth was modulated by maternal nutritional modifications. In humans, placental villi were collected from pathological pregnancies (i.e. with IUGR or fetal macrosomia). Placental FTO mRNA expression was reduced by IUGR but was not significantly affected by macrosomia in either rats or humans. Our data suggest that placental FTO may participate in interactions between the in utero environment and the control of fetal growth under IUGR conditions by modulating epigenetic processes.
RESUMO
Epidemiological studies suggest that maternal undernutrition sensitises to the development of chronic adult diseases, such as type 2 diabetes, hypertension and obesity. Although the physiological mechanisms involved in this 'perinatal programming' remain largely unknown, alterations of stress neuroendocrine systems such as the hypothalamic-pituitary-adrenal (HPA) and sympathoadrenal axes might play a crucial role. Despite recent reports showing that maternal perinatal undernutrition disturbs chromaffin cells organisation and activity in male rats at weaning, its long-term effects on adrenal medulla in adult animals are unknown. Using a rat model of maternal perinatal 50% food restriction (FR50) from the second week of gestation until weaning, histochemistry approaches revealed alterations in noradrenergic chromaffin cells aggregation and in cholinergic innervation in the adrenal medulla of 8-month-old FR50 rats. Electron microscopy showed that chromaffin cell granules exhibited ultrastructural changes in FR50 rats. These morphological changes were associated with reduced circulating levels and excretion of catecholamines. By contrast, catecholamine plasma levels were significantly increased after a 16 or 72 h of fasting, indicating that the responsiveness of the sympathoadrenal system to food deprivation was accentuated in FR50 adult rats. Among 384 pituitary adenylate cyclase-activating polypeptide-sensitive genes, we identified 129 genes (33.6%) that were under expressed (ratio < 0.7) in FR50 animals. A large number of these genes are involved in cytoskeleton remodelling and vesicle trafficking. Taken together, our results show that maternal perinatal undernutrition programmes adrenomedullary function and gene expression in adult male rats. Because catecholamines contribute to metabolic homeostasis, as well as arterial blood pressure regulation, the alterations observed in the adrenal medulla of adult male FR50 rats may participate in the programming of chronic adult diseases.
Assuntos
Medula Suprarrenal/anatomia & histologia , Medula Suprarrenal/fisiologia , Expressão Gênica , Desnutrição/fisiopatologia , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Acetilcolinesterase/metabolismo , Animais , Animais Recém-Nascidos/fisiologia , Peso Corporal , Feminino , Privação de Alimentos/fisiologia , Humanos , Sistema Hipotálamo-Hipofisário/fisiologia , Masculino , Sistema Hipófise-Suprarrenal/fisiologia , Gravidez , Ratos , Ratos Wistar , DesmameRESUMO
The brain-derived neurotrophic factor (BDNF) has been shown to exert an important role during implantation, placental development, and fetal growth control in mice. Its expression is closely related to the nutritional status in several tissues such as in the nervous system. In a previous study, we demonstrated that maternal undernutrition (MU), during the perinatal life, modified both the BDNF and its functional receptor, the tyrosine kinase receptor B (TrkB) gene expression in the brain of growth-restricted rat offspring during sensitive developmental windows, suggesting that these early modifications may have long-lasting consequences. In the present study, we measured BDNF/TrkB mRNA and protein levels in rat placentas from mothers submitted to a 50% food restriction during gestation, and in human placentas from pregnancies with fetal growth restriction or fetal macrosomia. In the rat, two subtypes of placental TrkB receptors have been identified: the TrkB-FL and TrkB-T1 receptors. We found that MU induced intrauterine growth restriction (IUGR) of fetuses at term and decreased the placental BDNF mRNA and protein levels. Placentae from undernourished mothers exhibited an increased mRNA expression of TrkB-FL whereas both TrkB-FL and TrkB-T1 receptors proteins levels were not modified. In human IUGR placentas, both BDNF and TrkB receptor mRNA expressions were up-regulated. Finally, although neither BDNF nor TrkB mRNA levels were altered by fetal macrosomia alone, BDNF mRNA levels were decreased when macrosomia was associated with maternal type 1 diabetes. These results show that the placental BDNF/TrkB system is modulated in rats and humans during pregnancies with fetal growth perturbations and is affected by the maternal energetic status. These data suggest that this system may exert an important role for the feto-placental unit development and that it may also be implicated in the etiology of pathologies related to placental and fetal growth disturbances.
Assuntos
Fator Neurotrófico Derivado do Encéfalo/genética , Retardo do Crescimento Fetal/metabolismo , Receptor trkB/genética , Animais , Feminino , Macrossomia Fetal/metabolismo , Humanos , Desnutrição/fisiopatologia , Fenômenos Fisiológicos da Nutrição Materna/fisiologia , Gravidez , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Transdução de SinaisRESUMO
Maternal perinatal undernutrition (MPU) modifies the activity of the hypothalamic-pituitary-adrenal axis and sensitises to the development of metabolic and cognitive adult diseases. Because the hypothalamus and hippocampus are involved in the regulation of neuroendocrine activity, energy metabolism and cognition, we hypothesised that a maternal 50% food restriction (FR50) from day 14 of pregnancy (E14) until postnatal day 21 (P21) would affect the development of these structures in male rat offspring. Protein and mRNA levels of brain-derived neurotrophic factor (BDNF) and cell proliferation [analysed by 5-bromodeoxyuridine (BrdU) incorporation] were compared in both control and FR50 rats from E21 to P22. Although the pattern of the evolution of BDNF concentration and cell proliferation throughout development was not strikingly different between groups, several disturbances at specific developmental stages were observed. FR50 rats exhibited a delayed increase of hippocampal BDNF content whereas, in the hypothalamus, BDNF level was augmented from E21 to P14 and associated, at this latter stage, with an increased mRNA expression of TRkB-T2. In both groups, a correlation between BDNF content and the number of BrdU positive cells was noted in the dentate gyrus, whereas opposite variations were observed in CA1, CA2 and CA3 layers, and in the arcuate and ventromedial nuclei. In the hippocampus, P15-FR50 rats showed an increased number of BrdU positive cells in all regions, whereas, at P22, a decrease was observed in the CA2. In the hypothalamus, between E21 and P8, MPU increases the number of BrdU positive cells in all regions analysed and, until P15, marked differences were noticed in the median eminence, the paraventricular nucleus and the arcuate nucleus. Taken together, the results obtained in the present study show that MPU changes the time course of production of BDNF and cell proliferation in specific hippocampal and hypothalamic areas during sensitive developmental windows, suggesting that these early perinatal modifications may have long-lasting consequences.