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Impaired hypothalamic mTOR activation in the adult rat offspring born to mothers fed a low-protein diet.

ABSTRACT: Several epidemiological and experimental studies have clearly established that maternal malnutrition induces a high risk of developing obesity and related metabolic diseases in the offspring. To determine if altered nutrient sensing might underlie this enhanced disease susceptibility, here we examined the effects of perinatal protein restriction on the activation of the nutrient sensor mTOR in response to acute variations in the nutritional status of the organism. Female Wistar rats were fed isocaloric diets containing either 17% protein (control) or 8% protein (PR) throughout pregnancy and lactation. At weaning offspring received standard chow and at 4 months of age the effects of fasting or fasting plus re-feeding on the phosphorylation levels of mTOR and its downstream target S6 ribosomal protein (rpS6) in the hypothalamus were assessed by immuno-fluorescence and western blot. Under ad libitum feeding conditions, PR rats exhibited decreased mTOR and rpS6 phosphorylation in the arcuate (ARC) and ventromedial (VMH) hypothalamic nuclei. Moreover, the phosphorylation of mTOR and rpS6 in these hypothalamic nuclei decreased with fasting in control but not in PR animals. Conversely, PR animals exhibited enhanced number of pmTOR imunostained cells in the paraventricular nucleus (PVN) and fasting decreased the activation of mTOR in the PVN of malnourished but not of control rats. These alterations occurred at a developmental stage at which perinatally-undernourished animals do not show yet obesity or glucose intolerance. Collectively, our observations suggest that altered hypothalamic nutrient sensing in response to an inadequate foetal and neonatal energetic environment is one of the basic mechanisms of the developmental programming of metabolic disorders and might play a causing role in the development of the metabolic syndrome induced by malnutrition during early life.

SUBMITTER: Guzman-Quevedo O

PROVIDER: S-EPMC3767644 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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Impaired hypothalamic mTOR activation in the adult rat offspring born to mothers fed a low-protein diet.

Guzmán-Quevedo Omar O Da Silva Aragão Raquel R Pérez García Georgina G Matos Rhowena J B RJ de Sa Braga Oliveira André A Manhães de Castro Raul R Bolaños-Jiménez Francisco F

PloS one 20130909 9

Several epidemiological and experimental studies have clearly established that maternal malnutrition induces a high risk of developing obesity and related metabolic diseases in the offspring. To determine if altered nutrient sensing might underlie this enhanced disease susceptibility, here we examined the effects of perinatal protein restriction on the activation of the nutrient sensor mTOR in response to acute variations in the nutritional status of the organism. Female Wistar rats were fed iso ...[more]

PMID: 24040371

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Project description:BackgroundMetabolic and endocrine environment during early life is crucial for metabolic imprinting. When dams were fed a high fat diet (HF diet), rat offspring developed hypothalamic leptin resistance with lean phenotype when weaned on a normal diet. Interestingly, when grown on the HF diet, they appeared to be protected against the effects of HF diet as compared to offspring of normally fed dams. The mechanisms involved in the protective effect of maternal HF diet are unclear.Methodology/principal findingsWe thus investigated the impact of maternal high fat diet on offspring subjected to normal or high palatable diet (P diet) on metabolic and endocrine parameters. We compared offspring born to dams fed P or HF diet. Offspring born to dams fed control or P diet, when fed P diet exhibited a higher body weight, altered hypothalamic leptin sensitivity and metabolic parameters suggesting that maternal P diet has no protective effect on offspring. Whereas, maternal HF diet reduces body weight gain and circulating triglycerides, and ameliorates corpulence index of offspring, even when subjected to P diet. Interestingly, this protective effect is differently expressed in male and female offspring. Male offspring exhibited higher energy expenditure as mirrored by increased hypothalamic UCP-2 and liver AdipoR1/R2 expression, and a profound change in the arcuate nucleus astrocytic organization. In female offspring, the most striking impact of maternal HF diet is the reduced hypothalamic expression of NPY and POMC.Conclusions/significanceHF diet given during gestation and lactation protects, at least partially, offspring from excessive weight gain through several mechanisms depending upon gender including changes in arcuate nucleus astrocytic organization and increased hypothalamic UCP-2 and liver AdipoR1/2 expression in males and reduced hypothalamic expression of NPY and POMC in females. Taken together our results reveal new mechanisms involved in the protective effect of maternal HF diet.

Project description:BACKGROUND & AIMS: Inflammatory Bowel Diseases (IBD), including Crohn’s disease and ulcerative colitis, are chronic illnesses that are thought to develop secondary to a pathologic interaction between the immune system and the intestinal microflora that is manifested by the gut mucosa. IBD has been recognized as disorders in which developmental epigenetic changes, such as DNA methylation, may play an important pathogenic role. DNA methylation can be influenced in mammals by dietary exposures. A methyl-donor diet has been specifically found to be effective in inducing permanent changes in DNA methylation at certain genomic loci in murine models. Importantly, the methyl-donor substances utilized are routinely incorporated into prenatal micronutrient supplements for humans. In this study we addressed whether maternal exposure to a methyl-donor diet induces prolonged alterations in offspring colitis susceptibility and whether it leads to stable colonic mucosal epigenetic changes and gene expression alterations in mice. We also assessed whether the maternal methyl-donor diet induced persistent changes in the colonic microbiota in the offspring. METHODS: Colonic mucosa from offspring of mothers fed a methyl donor diet (MD) or control diet was interrogated by methylation specific amplification microarray (MSAM) at postnatal day 30 (P30) and P90 to screen for changes in DNA methylation, with bisulfite pyrosequencing validation. Transcriptomic changes in the same tissue were analyzed by microarray expression profiling and real time RT-PCR. The mucosal microbiome was studied by high throughput, detailed pyrosequencing of 16S rRNA. RESULTS: MD exposure during prenatal and early development lead to a significant increase in colitis susceptibility that persisted even after 69 days of diet reversal (P90). MD exposure also influenced DNA methylation and expression at select genomic loci. Overlap between DNA methylation and gene expression changes was confirmed at Ppara, a gene previously implicated in murine colitis. Metagenomic analyses failed to reveal consistent bacteriomic differences between the P30 and P90 age groups. CONCLUSIONS: Prenatal and early developmental exposure to MD induces increased colitis susceptibility, mucosal epigenomic, and transcriptomic changes that do not appear to associate with consistent microbiomic alterations. These findings underscore the importance of maternal nutrition on offspring colitis susceptibility in mammals and implicate the importance of the associated mucosal epigenetic modification. Our results bare potentially significant public health relevance as well.

Project description:BACKGROUND & AIMS: Inflammatory Bowel Diseases (IBD), including Crohnâ??s disease and ulcerative colitis, are chronic illnesses that are thought to develop secondary to a pathologic interaction between the immune system and the intestinal microflora that is manifested by the gut mucosa. IBD has been recognized as disorders in which developmental epigenetic changes, such as DNA methylation, may play an important pathogenic role. DNA methylation can be influenced in mammals by dietary exposures. A methyl-donor diet has been specifically found to be effective in inducing permanent changes in DNA methylation at certain genomic loci in murine models. Importantly, the methyl-donor substances utilized are routinely incorporated into prenatal micronutrient supplements for humans. In this study we addressed whether maternal exposure to a methyl-donor diet induces prolonged alterations in offspring colitis susceptibility and whether it leads to stable colonic mucosal epigenetic changes and gene expression alterations in mice. We also assessed whether the maternal methyl-donor diet induced persistent changes in the colonic microbiota in the offspring. METHODS: Colonic mucosa from offspring of mothers fed a methyl donor diet (MD) or control diet was interrogated by methylation specific amplification microarray (MSAM) at postnatal day 30 (P30) and P90 to screen for changes in DNA methylation, with bisulfite pyrosequencing validation. Transcriptomic changes in the same tissue were analyzed by microarray expression profiling and real time RT-PCR. The mucosal microbiome was studied by high throughput, detailed pyrosequencing of 16S rRNA. RESULTS: MD exposure during prenatal and early development lead to a significant increase in colitis susceptibility that persisted even after 69 days of diet reversal (P90). MD exposure also influenced DNA methylation and expression at select genomic loci. Overlap between DNA methylation and gene expression changes was confirmed at Ppara, a gene previously implicated in murine colitis. Metagenomic analyses failed to reveal consistent bacteriomic differences between the P30 and P90 age groups. CONCLUSIONS: Prenatal and early developmental exposure to MD induces increased colitis susceptibility, mucosal epigenomic, and transcriptomic changes that do not appear to associate with consistent microbiomic alterations. These findings underscore the importance of maternal nutrition on offspring colitis susceptibility in mammals and implicate the importance of the associated mucosal epigenetic modification. Our results bare potentially significant public health relevance as well. 4 independent MD versus control comparisons at P90 were performed as follows. RNA (0.4ug) samples were processed and labelled with Cy3 and Cy5 (Quick Amp labelling kit, two color, Agilent technologies) and 4 independent P90 MD to P90 control comparisons were done on Agilent technologies 4x44k whole genomic expression microarray G2519F, Amadid:014868)

Project description:ObjectiveAmylin was found to regulate glucose and lipid metabolism by acting on the arcuate nucleus of the hypothalamus (ARC). Maternal high-fat diet (HFD) induces sex-specific metabolic diseases mediated by the ARC in offspring. This study was performed to explore 1) the effect of maternal HFD-induced alterations in amylin on the differentiation of hypothalamic neurons and metabolic disorders in male offspring and 2) the specific molecular mechanism underlying the regulation of amylin and its receptor in response to maternal HFD.MethodsMaternal HFD and gestational hyper-amylin mice models were established to explore the role of hypothalamic amylin and receptor activity-modifying protein 3 (Ramp3) in regulating offspring metabolism. RNA pull-down, mass spectrometry, RNA immunoprecipitation, and RNA decay assays were performed to investigate the mechanism underlying the influence of maternal HFD on Ramp3 deficiency in the fetal hypothalamus.ResultsMale offspring with maternal HFD grew heavier and developed metabolic disorders, whereas female offspring with maternal HFD showed a slight increase in body weight and did not develop metabolic disorders compared to those exposed to maternal normal chow diet (NCD). Male offspring exposed to a maternal HFD had hyperamylinemia from birth until adulthood, which was inconsistent with offspring exposed to maternal NCD. Hyperamylinemia in the maternal HFD-exposed male offspring might be attributed to amylin accumulation following Ramp3 deficiency in the fetal hypothalamus. After Ramp3 knockdown in hypothalamic neural stem cells (htNSCs), amylin was found to fail to promote the differentiation of anorexigenic alpha-melanocyte-stimulating hormone-proopiomelanocortin (?-MSH-POMC) neurons but not orexigenic agouti-related protein-neuropeptide Y (AgRP-Npy) neurons. An investigation of the mechanism involved showed that IGF2BP1 could specifically bind to Ramp3 in htNSCs and maintain its mRNA stability. Downregulation of IGF2BP1 in htNSCs in the HFD group could decrease Ramp3 expression and lead to an impairment of ?-MSH-POMC neuron differentiation.ConclusionsThese findings suggest that gestational exposure to HFD decreases the expression of IGF2BP1 in the hypothalami of male offspring and destabilizes Ramp3 mRNA, which leads to amylin resistance. The subsequent impairment of POMC neuron differentiation induces sex-specific metabolic disorders in adulthood.

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Impaired hypothalamic mTOR activation in the adult rat offspring born to mothers fed a low-protein diet.

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Impaired hypothalamic mTOR activation in the adult rat offspring born to mothers fed a low-protein diet.

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