Maternal Low Protein Research Articles

The long-term effect of maternal dietary protein restriction on 5-HT1A receptor function and behavioral responses to stress in adulthood

Maternal nutrition impacts fetal development, and may play a role in determining resilience to stress and vulnerability to stress-precipitated psychiatric disorders, such as anxiety and depression. In this study, we examined the effect of a reduction in maternal dietary protein during pregnancy on the brain neurochemistry and behavior of offspring. We focused specifically on the serotonin system, the 5-HT1A receptor and the responsivity of offspring as adults to stress. Dams were fed either a low protein diet (10% protein by weight) or isocaloric control diet (20% protein by weight). The low protein diet did not alter maternal food intake and body weight, or litter size and the average birth weight of male or female littermates. 5-HT1A receptor function, as measured by quantitative autoradiography of 8-OH-DPAT (1 μM)-stimulated [35S]GTPγS binding, was markedly reduced in hippocampus of weanling female, but not male offspring (postnatal day, PND 21) of dams fed the low protein diet. The number of serotonergic cell bodies in the rostral raphe, and 5-HT metabolism in the limbic system of weanling offspring was not altered by maternal low protein diet. The deficit in hippocampal 5-HT1A receptor function observed in weanling female offspring persisted into adulthood (PND 112), and was accompanied by an increased sensitivity to stress, specifically increased immobility during a 15-minute forced swim challenge and increased anorexia following 30-minute restraint (PND 97-100). The present work begins to uncover important future directions for understanding the early developmental origins of resilience to stress, and factors that may put individuals at greater risk for stress-related psychiatric disorders.

Insulin and branched-chain amino acid depletion during mouse preimplantation embryo culture programmes body weight gain and raised blood pressure during early postnatal life

Mouse maternal low protein diet exclusively during preimplantation development (Emb-LPD) is sufficient to programme altered growth and cardiovascular dysfunction in offspring. Here, we use an in vitro model comprising preimplantation culture in medium depleted in insulin and branched-chain amino acids (BCAA), two proposed embryo programming inductive factors from Emb-LPD studies, to examine the consequences for blastocyst organisation and, after embryo transfer (ET), postnatal disease origin. Two-cell embryos were cultured to blastocyst stage in defined KSOM medium supplemented with four combinations of insulin and BCAA concentrations. Control medium contained serum insulin and uterine luminal fluid amino acid concentrations (including BCAA) found in control mothers from the maternal diet model (N-insulin+N-bcaa). Experimental medium (three groups) contained 50% reduction in insulin and/or BCAA (L-insulin+N-bcaa, N-insulin+L-bcaa, and L-insulin+N-bcaa). Lineage-specific cell numbers of resultant blastocysts were not affected by treatment. Following ET, a combined depletion of insulin and BCAA during embryo culture induced a non sex-specific increase in birth weight and weight gain during early postnatal life. Furthermore, male offspring displayed relative hypertension and female offspring reduced heart/body weight, both characteristics of Emb-LPD offspring. Combined depletion of metabolites also resulted in a strong positive correlation between body weight and glucose metabolism that was absent in the control group. Our results support the notion that composition of preimplantation culture medium can programme development and associate with disease origin affecting postnatal growth and cardiovascular phenotypes and implicate two important nutritional mediators in the inductive mechanism. Our data also have implications for human assisted reproductive treatment (ART) practice.

Perinatal Malnutrition Leads to Sexually Dimorphic Behavioral Responses with Associated Epigenetic Changes in the Mouse Brain

Childhood malnutrition is a risk factor for mental disorders, such as major depression and anxiety. Evidence shows that similar early life adversities induce sex-dependent epigenetic reprogramming. However, little is known about how genes are specifically affected by early malnutrition and the implications for males and females respectively. One relevant target is neuropeptide Y (NPY), which regulates both stress and food-intake. We studied maternal low protein diet (LPD) during pregnancy/lactation in mice. Male, but not female, offspring of LPD mothers consistently displayed anxiety- and depression-like behaviors under acute stress. Transcriptome-wide analysis of the effects of acute stress in the amygdala, revealed a list of transcription factors affected by either sex or perinatal LPD. Among these immediate early genes (IEG), members of the Early growth response family (Egr1/2/4) were consistently upregulated by perinatal LPD in both sexes. EGR1 also bound the NPY receptor Y1 gene (Npy1r), which co-occurred with sex-specific effects of perinatal LPD on both Npy1r DNA-methylation and gene transcription. Our proposed pathway connecting early malnutrition, sex-independent regulatory changes in Egr1, and sex-specific epigenetic reprogramming of its effector gene, Npy1r, represents the first molecular evidence of how early life risk factors may generate sex-specific epigenetic effects relevant for mental disorders.

Early gestational maternal low-protein diet diminishes hepatic response to fasting in young adult male mice

Maternal low-protein (MLP) diet can lead to hepatic steatosis, which only develops with ageing. It is still unclear whether the young offspring show any signs of past exposure to prenatal adverse conditions. We hypothesized that early nutritional insult would first affect the dynamic responsiveness to nutritional challenges rather than the static state. We analyzed the transcriptome and metabolome profiles of the hepatic response to fasting/refeeding in young male mice offspring to identify changes induced by early gestational MLP diet. Restricted MLP exposure strictly to early gestation was achieved by the embryo transfer method. As a result, the fasting-induced upregulation of genes related to long-chain fatty acid metabolism and of stress response genes related to protein folding were significantly diminished in MLP pups. Lipid profiling after fasting showed that the hepatic signature of triacylglycerols was shifted to longer acyl-chains and higher saturation by the MLP diet. Bioinformatic analyses suggested that these phenomenological changes may be partially linked to the peroxisome proliferator activated receptor α (PPARα) pathway. Taken together, early gestational MLP diet affected the hepatic dynamic response to nutritional stress in seemingly healthy young offspring, accompanied with partial deterioration of PPARα action.

Maternal protein intake in pregnancy and offspring metabolic health at age 9–16 y: results from a Danish cohort of gestational diabetes mellitus pregnancies and controls

Background: Recent years have seen strong tendencies toward high-protein diets. However, the implications of higher protein intake, especially during developmentally sensitive periods, are poorly understood. Conversely, evidence on the long-term developmental consequences of low protein intake in free-living populations remains limited.Objective: We examined the association of protein intake in pregnancy with offspring metabolic health at age 9-16 y in a longitudinal cohort that oversampled pregnancies with gestational diabetes mellitus (GDM).Design: Six hundred eight women with an index pregnancy affected by gestational diabetes mellitus and 626 controls enrolled in the Danish National Birth Cohort were used for the analysis. Protein (total, animal, vegetable) intake was assessed by using a food-frequency questionnaire in gestational week 25. The offspring underwent a clinical examination including fasting blood samples and a dual-energy X-ray absorptiometry scan (subset of 650) from which metabolic outcomes were derived. Multivariable analyses were conducted applying a 1:1 substitution of carbohydrates for protein.Results: The mean ± SD protein intake in pregnancy was 93 ± 15 g/d (16% ± 3% of energy) in GDM-exposed women and 90 ± 14 g/d (16% ± 2% of energy) in control women. There were overall no associations between maternal protein intake and offspring fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR). We found that maternal total protein intake was associated with a tendency for a higher abdominal fat mass percentage (quartile 4 compared with quartile 1: 0.40 SD; 95% CI: -0.03, 0.83 SD; P = 0.07) in GDM-exposed offspring and a tendency for a higher total fat mass percentage among male offspring (quartile 4 compared with quartile 1: 0.33 SD; 95% CI: -0.01, 0.66 SD; P = 0.06), but a small sample size may have compromised the precision of the effect estimates. GDM-exposed offspring of mothers with a protein intake in the lowest decile (≤12.5% of energy compared with >12.5% of energy) had lower fasting insulin (ratio of geometric means: 0.82; 95% CI: 0.68, 0.99; P = 0.04) and a tendency toward lower HOMA-IR (ratio of geometric means: 0.82; 95% CI: 0.66, 1.02; P = 0.07), but there was no evidence of associations with body composition. Male offspring seemed to derive a similar benefit from a maternal low protein intake as did GDM-exposed offspring.Conclusions: Overall, our results provide little support for an association of maternal protein intake in pregnancy with measures of offspring metabolic health. Further studies in larger cohorts are needed to determine whether low maternal protein intake in pregnancy may improve glucose homeostasis in GDM-exposed and male offspring.

Maternal low-protein diet decreases brain-derived neurotrophic factor expression in the brains of the neonatal rat offspring

Prenatal exposure to a maternal low-protein (LP) diet has been known to cause cognitive impairment, learning and memory deficits. However, the underlying mechanisms have not been identified. Herein, we demonstrate that a maternal LP diet causes, in the brains of the neonatal rat offspring, an attenuation in the basal expression of the brain-derived neurotrophic factor (BDNF), a neurotrophin indispensable for learning and memory. Female rats were fed either a 20% normal protein (NP) diet or an 8% LP 3 weeks before breeding and during the gestation period. Maternal LP diet caused a significant reduction in the Bdnf expression in the brains of the neonatal rats. We further found that the maternal LP diet reduced the activation of the cAMP/protein kinase A/cAMP response element binding protein (CREB) signaling pathway. This reduction was associated with a significant decrease in CREB binding to the Bdnf promoters. We also show that prenatal exposure to the maternal LP diet results in an inactive or repressed exon I and exon IV promoter of the Bdnf gene in the brain, as evidenced by fluxes in signatory hallmarks in the enrichment of acetylated and trimethylated histones in the nucleosomes that envelop the exon I and exon IV promoters, causing the Bdnf gene to be refractory to transactivation. Our study is the first to determine the impact of a maternal LP diet on the basal expression of BDNF in the brains of the neonatal rats exposed prenatally to an LP diet.

Prenatal exposure to a maternal LP diet decreases BDNF expression in the brains of the neonatal offspring

Prenatal exposure to a maternal low protein diet has been known to cause cognitive deficits in the adult progeny. Maternal low protein diets induce visual and spatial memory impairment, deficits in learning and memory, as well as a host of behavioral abnormalities in the adult progeny. However, the underlying causes and the molecular mechanisms have not been identified. Herein, we demonstrate that a maternal low protein (LP) diet causes, in the brains of the male and female neonatal rat offspring, an attenuation in the basal expression of the Brain‐derived neurotrophic factor (BDNF), a neurotrophin essential for neuronal survival and indispensable for learning and memory. Sprague‐Dawley female rats were fed either a 20% normal protein diet (NP) or an 8% low protein (LP) diet inducted at three weeks before breeding and continued for the entirety of the gestation period. Maternal LP diet caused a significant reduction in the Bdnf expression in the whole brains of the male and female neonatal rat offspring. We delineated the molecular mechanisms further, and found that a maternal LP diet –1) decreases cAMP levels and the ensuing protein kinase A (PKA) activation, that 2) consequently reduces CREB activation, which 3) culminates in a significant reduction in cAMP response element binding protein (CREB) binding to the Bdnf promoters – in the brains of male and female neonatal offspring. We further show that prenatal exposure of the neonatal male and female offspring to a maternal LP diet results in a characteristic inactive or repressed exon I and exon IV promoter of the Bdnf gene in the brain, as evidenced by fluxes in signatory hallmarks in the enrichment of acetylated and trimethylated histones in the nucleosomes that envelop the exon I and exon IV promoters of the Bdnf gene. Our study shows that prenatal exposure to a maternal LP diet results in the attenuation of basal Bdnf gene expression in the brains of the neonatal progeny through reduced activation of the cAMP/PKA/CREB pathway accompanied by changes in histone modification that make the exon I and exon IV promoter of the Bdnf gene refractory to transactivation.Support or Funding InformationThis work was supported by National Institutes of Health, Grant # R01AG0145264, to Dr. Othman Ghribi.

Maternal low protein diet decreases leptin expression in the brains of the neonatal rat offspring

Maternal low protein (LP) diets during gestation cause learning and memory impairment as well as cognitive deficits in the neonatal and adult offspring. The cellular and molecular mechanism that mediate the deleterious effects of prenatal exposure to a maternal LP diet on cognitive function is egregiously understood. Leptin, an adipocytokine expressed endogenously in the brain, exhibits pleiotropic effects in the brain and plays an indispensable role in learning and memory, as well as neuronal survival. In this study, we show that prenatal exposure to a maternal LP diet results in the mitigation of basal expression of leptin in the brains of the neonatal rat offspring. Sprague‐Dawley female rats were fed either a 20% normal protein diet (NP) or an 8% low protein (LP) diet inducted at three weeks before breeding and continued for the entirety of the gestation period. Prenatal exposure to a maternal LP diet resulted in reduced leptin expression in the brains of the neonatal offspring that was ascribed to a reduction in the C/EBPα and C/EBPβ – mediated transactivation of the leptin promoter. We further delved into and delineated the upstream molecular mediators and elucidated the role of lower CREB‐mediated transcription of C/EBPα and C/EBPβ that resulted in a reduction of the basal expression of C/EBPα and C/EBPβ leading to a significant attenuation in their transcriptional activities in the brains of the neonatal progeny prenatally exposed to a maternal LP diet. This decrease in transcriptional activity of C/EBPα and C/EBPβ results in the attenuation of the basal leptin promoter activity. Furthermore, maternal LP diet also induces a reduction in the enrichment of the acetylated histones in the nucleosomes that envelope the leptin promoter thereby making it refractory to trans‐activation. Our study unveils a mitigation of leptin expression in the brain as a novel mechanistic insight and a conduit into the deleterious effects evoked by prenatal exposure to a maternal LP diet on cognitive function.Support or Funding InformationThis work was supported by National Institutes of Health, Grant # R01AG0145264, to Dr. Othman Ghribi.

Effects of high-fat diet on somatic growth, metabolic parameters and function of peritoneal macrophages of young rats submitted to a maternal low-protein diet.

This study evaluated the effects of a post-weaning high-fat (HF) diet on somatic growth, food consumption, metabolic parameters, phagocytic rate and nitric oxide (NO) production of peritoneal macrophages in young rats submitted to a maternal low-protein (LP) diet. Male Wistar rats (aged 60 d) were divided in two groups (n 22/each) according to their maternal diet during gestation and lactation: control (C, dams fed 17 % casein) and LP (dams fed 8 % casein). At weaning, half of the groups were fed HF diet and two more groups were formed (HF and low protein-high fat (LP-HF)). Somatic growth, food and energy intake, fat depots, serum glucose, cholesterol and leptin concentrations were evaluated. Phagocytic rate and NO production were analysed in peritoneal macrophages under stimulation of zymosan and lipopolysaccharide (LPS)+interferon γ (IFN-γ), respectively. The maternal LP diet altered the somatic parameters of growth and development of pups. LP and LP-HF pups showed a higher body weight gain and food intake than C pups. HF and LP-HF pups showed increased retroperitoneal and epididymal fat depots, serum level of TAG and total cholesterol compared with C and LP pups. After LPS+IFN-γ stimulation, LP and LP-HF pups showed reduced NO production when compared with their pairs. Increased phagocytic activity and NO production were seen in LP but not LP-HF peritoneal macrophages. However, peritoneal macrophages of LP pups were hyporesponsive to LPS+IFN-γ induced NO release, even after a post-weaning HF diet. Our data demonstrated that there was an immunomodulation related to dietary fatty acids after the maternal LP diet-induced metabolic programming.

Maternal low-protein diet in female rat heart: possible protective effect of estradiol.

Several studies have shown that maternal low-protein (LP) diet induces detrimental effects in cardiovascular system and oxidative stress in male animals. Additional studies suggested that female has lower incidence of cardiovascular disease. However until present data, the possible effects of estradiol on the undernutrition during gestational and lactation periods are not discussed. The present study was conducted to evaluate the effects of a maternal LP diet during gestational and lactation period on oxidative balance in the female rat hearts ventricles at two ages. Dams were fed with normal protein (NP) or a LP diet during the gestational and lactation period, and their female offspring were divided into age groups (22 or 122 days, corresponding to a low or high estrogen level) composing four experimental groups. Evaluating the nutritional effect showed an increase in oxidative stress biomarkers and decrease in enzymatic defense in LP-22D compared with NP-22D. In contrast, no changes were observed in malondialdehyde and carbonyls, but an increase in glutathione-S-transferase (GST) activity in the LP-122D compared with NP-122D. The global oxy-score in the LP-22D group indicated a predominance of oxidative damage when compared with NP-22D, while in LP-122D group the global oxy-score was restored to NP-122D levels. Evaluating the estradiol effect, our data show a significant decrease in oxidative stress with increase in CAT and GST activity, associated with increase in intracellular thiols. Our data suggest that in situation with low levels of estradiol, hypoproteic diet during gestation and lactation period has detrimental effects on heart, however when estradiol levels raise, the detrimental effects induced are mitigated.

Amino acid starvation-induced autophagy is involved in reduced subcutaneous fat deposition in weaning piglets derived from sows fed low-protein diet during gestation and lactation : Autophagy is involved in reduced fat deposition in maternal low-protein piglets.

The study aimed to determine the effects of maternal low-protein (LP) diet on subcutaneous fat deposition of weaning piglets and the potential mechanism. Sows were fed either a standard protein (SP, 15 and 18% crude protein) or a LP diet (50% protein levels of SP) throughout pregnancy and lactation. Subcutaneous fat and blood were sampled from male piglets at 28 days of age. Serum biochemical metabolites and hormone concentrations were detected with the enzymatic colorimetric methods. Serum-free amino acid (FAA) levels were measured by amino acid auto-analyzer. The mRNA and protein were measured by qRT-PCR and Western blot. Body weight, back fat thickness, triglycerides concentrations in subcutaneous fat tissue, and serum, as well as FFA concentrations were significantly reduced in LP piglets when compared with SP piglets. Further studies showed that mRNA and protein expression of acetyl-CoA carboxylase and fatty acid synthetase, two key enzymes of de novo lipogenesis, were significantly reduced in LP piglets, while mRNA expression and the lipolytic enzymes activities of lipolysis genes, adipose triglyceride lipase and hormone-sensitive lipase, were significantly increased. Furthermore, expression of autophagy-related gene 7 and autophagy maker gene microtubule-associated protein 1A/1B-light chain 3 (LC 3) as well as the conversion of LC3I to LC3II were significantly elevated, along with the expression of activating transcription factor-4 and eukaryotic translation initiation factor-2a. These results indicate that amino acid starvation-induced autophagy is involved in reduced subcutaneous fat deposition in maternal LP weaning piglets, demonstrating links between maternal protein restriction and offspring fat deposition.

Effects of prenatal low protein and postnatal high fat diets on visceral adipose tissue macrophage phenotypes and IL-6 expression in Sprague Dawley rat offspring.

Adipose tissue macrophages (ATM) are implicated in adipose tissue inflammation and obesity-related insulin resistance. Maternal low protein models result in fetal programming of obesity. The study aims to answer whether maternal undernutrition by protein restriction affects the ATM M1 or M2 phenotype under postnatal high fat diet in F1 offspring. Using a rat model of prenatal low protein (LP, 8% protein) diet followed by a postnatal high fat energy diet (HE, 45% fat) or low fat normal energy diet (NE, 10% fat) for 12 weeks, we investigated the effects of these diets on adiposity, programming of the offspring ATM phenotype, and the associated inflammatory response in adipose tissue. Fat mass in newborn and 12-week old LP fed offspring was lower than that of normal protein (20%; NP) fed offspring; however, the adipose tissue growth rate was higher compared to the NP fed offspring. While LP did not affect the number of CD68+ or CD206+ cells in adipose tissue of NE offspring, it attenuated the number of these cells in offspring fed HE. In offspring fed HE, LP offspring had a lower percentage of CD11c+CD206+ ATMs, whose abundancy was correlated with the size of the adipocytes. Noteworthy, similar to HE treatment, LP increased gene expression of IL-6 within ATMs. Two-way ANOVA showed an interaction of prenatal LP and postnatal HE on IL-6 and IL-1β transcription. Overall, both LP and HE diets impact ATM phenotype by affecting the ratio of CD11c+CD206+ ATMs and the expression of IL-6.

Chronic Maternal Low-Protein Diet in Mice Affects Anxiety, Night-Time Energy Expenditure and Sleep Patterns, but Not Circadian Rhythm in Male Offspring.

Offspring of murine dams chronically fed a protein-restricted diet have an increased risk for metabolic and neurobehavioral disorders. Previously we showed that adult offspring, developmentally exposed to a chronic maternal low-protein (MLP) diet, had lower body and hind-leg muscle weights and decreased liver enzyme serum levels. We conducted energy expenditure, neurobehavioral and circadian rhythm assays in male offspring to examine mechanisms for the body-weight phenotype and assess neurodevelopmental implications of MLP exposure. C57BL/6J dams were fed a protein restricted (8%protein, MLP) or a control protein (20% protein, C) diet from four weeks before mating until weaning of offspring. Male offspring were weaned to standard rodent diet (20% protein) and single-housed until 8–12 weeks of age. We examined body composition, food intake, energy expenditure, spontaneous rearing activity and sleep patterns and performed behavioral assays for anxiety (open field activity, elevated plus maze [EPM], light/dark exploration), depression (tail suspension and forced swim test), sociability (three-chamber), repetitive (marble burying), learning and memory (fear conditioning), and circadian behavior (wheel-running activity during light-dark and constant dark cycles). We also measured circadian gene expression in hypothalamus and liver at different Zeitgeber times (ZT). Male offspring from separate MLP exposed dams had significantly greater body fat (P = 0.03), less energy expenditure (P = 0.004), less rearing activity (P = 0.04) and a greater number of night-time rest/sleep bouts (P = 0.03) compared to control. MLP offspring displayed greater anxiety-like behavior in the EPM (P<0.01) but had no learning and memory deficit in fear-conditioning assay (P = 0.02). There was an effect of time on Per1, Per 2 and Clock circadian gene expression in the hypothalamus but not on circadian behavior. Thus, transplacental and early developmental exposure of dams to chronic MLP reduces food intake and energy expenditure, increases anxiety like behavior and disturbs sleep patterns but not circadian rhythm in adult male offspring.

Gestational Protein Restriction in Wistar Rats; Effect of Taurine Supplementation on Properties of Newborn Skeletal Muscle.

Taurine ameliorates changes occurring in newborn skeletal muscle as a result of gestational protein restriction in C57BL/6 mice, but taurine supplementation effects may be exaggerated in C57BL/6 mice due to their inherent excessive taurinuria.We examined if maternal taurine supplementation could ameliorate changes in gene expression levels, properties of mitochondria, myogenesis, and nutrient transport and sensing, in male newborn skeletal muscle caused by a maternal low protein (LP) diet in Wistar rats.LP diet resulted in an 11% non-significant decrease in birth weight, which was not rescued by taurine supplementation (LP-Tau). LP-Tau offspring had significantly lower birth weight compared to controls. Gene expression profiling revealed 895 significantly changed genes, mainly an LP-induced down-regulation of genes involved in protein translation. Taurine fully or partially rescued 32% of these changes, but with no distinct pattern as to which genes were rescued.Skeletal muscle taurine content in LP-Tau offspring was increased, but no changes in mRNA levels of the taurine synthesis pathway were observed. Taurine transporter mRNA levels, but not protein levels, were increased by LP diet.Nutrient sensing signaling pathways were largely unaffected in LP or LP-Tau groups, although taurine supplementation caused a decrease in total Akt and AMPK protein levels. PAT4 amino acid transporter mRNA was increased by LP, and normalized by taurine supplementation.In conclusion, gestational protein restriction in rats decreased genes involved in protein translation in newborn skeletal muscle and led to changes in nutrient transporters. Taurine partly rescued these changes, hence underscoring the importance of taurine in development.

Transcriptional response of skeletal muscle to a low protein perinatal diet in rat offspring at different ages: The role of key enzymes of glucose-fatty acid oxidation

Skeletal muscle is a plastic tissue during development with distinctive acute and chronic response to maternal protein restriction. This study evaluated gene and protein expression of key-enzymes of glycolytic pathway (HK2, PFK, PDK4 and CS), and fatty acid oxidation (CPT1 and β-HAD) of two different types of skeletal muscle [soleus and extensor digitorium longus (EDL)] from offspring rats at 30 and 90 days of age, exposed to maternal isoenergetic low protein diet throughout gestation and lactation. Pups from dams fed 17% protein diet (n=5, normal protein, Np), and low protein pups from dams fed 8% casein diet (low protein, Lp, n=5) were evaluated. Offspring were sacrificed either 30 or 90 days old. Soleus and EDL were analyzed for mRNA and protein expression by quantitative PCR and western blotting, respectively. Soleus was more affected by Lp maternal diet at 90 days by down-regulation of key enzymes of glycolytic pathway, in particular HK2 and PDK4 with a concomitant reduction of β-HAD mRNA. For EDL, the effects of Lp maternal diet were more pronounced at 30 days, as the transcriptional key enzymes of glycolytic pathway were down-regulated. One important finding was that the observed acute (30 days) transcriptional changes did not remain in adult Lp rats (90 days), except for PDK4. The robust PDK4 mRNA down-regulation, observed in both soleus and EDL, and at both ages, and the consequent down-regulation of the PDK4 protein expression can be responsible for a state of reduced metabolic flexibility of skeletal muscle in response to maternal low protein diet.

The effect of maternal undernutrition on the rat placental transcriptome: protein restriction up-regulates cholesterol transport.

BackgroundFetal exposure to a maternal low protein diet during rat pregnancy is associated with hypertension, renal dysfunction and metabolic disturbance in adult life. These effects are present when dietary manipulations target only the first half of pregnancy. It was hypothesised that early gestation protein restriction would impact upon placental gene expression and that this may give clues to the mechanism which links maternal diet to later consequences.MethodsPregnant rats were fed control or a low protein diet from conception to day 13 gestation. Placentas were collected and RNA sequencing performed using the Illumina platform.ResultsProtein restriction down-regulated 67 genes and up-regulated 24 genes in the placenta. Ingenuity pathway analysis showed significant enrichment in pathways related to cholesterol and lipoprotein transport and metabolism, including atherosclerosis signalling, clathrin-mediated endocytosis, LXR/RXR and FXR/RXR activation. Genes at the centre of these processes included the apolipoproteins ApoB, ApoA2 and ApoC2, microsomal triglyceride transfer protein (Mttp), the clathrin-endocytosis receptor cubilin, the transcription factor retinol binding protein 4 (Rbp4) and transerythrin (Ttr; a retinol and thyroid hormone transporter). Real-time PCR measurements largely confirmed the findings of RNASeq and indicated that the impact of protein restriction was often striking (cubilin up-regulated 32-fold, apoC2 up-regulated 17.6-fold). The findings show that gene expression in specific pathways is modulated by maternal protein restriction in the day-13 rat placenta.ConclusionsChanges in cholesterol transport may contribute to altered tissue development in the fetus and hence programme risk of disease in later life.Electronic supplementary materialThe online version of this article (doi:10.1186/s12263-016-0541-3) contains supplementary material, which is available to authorized users.

Suboptimal maternal diets alter mu opioid receptor and dopamine type 1 receptor binding but exert no effect on dopamine transporters in the offspring brain

Birthweight is a marker for suboptimal fetal growth and development in utero. Offspring can be born large for gestational age (LGA), which is linked to maternal obesity or excessive gestational weight gain, as well as small for gestational age (SGA), arising from nutrient or calorie deficiency, placental dysfunction, or other maternal conditions (hypertension, infection). In humans, LGA and SGA babies are at an increased risk for certain neurodevelopmental disorders, including Attention Deficit/Hyperactivity Disorder, schizophrenia, and social and mood disorders. Using mouse models of LGA (maternal high fat (HF) diet) and SGA (maternal low protein (LP) diet) offspring, our lab has previously shown that these offspring display alterations in the expression of mesocorticolimbic genes that regulate dopamine and opioid function, thus indicating that these brain regions and neurotransmitter systems are vulnerable to gestational insults. Interestingly, these two maternal diets affected dopamine and opioid systems in somewhat opposing directions (e.g., LP offspring are generally hyperdopaminergic with reduced opioid expression, and the reverse is found for the HF offspring). These data largely involved evaluation at the transcriptional level, so the present experiment was designed to extend these analyses through an assessment of receptor binding. In this study, control, SGA and LGA offspring were generated from dams fed control, low protein or high fat diet, respectively, throughout pregnancy and lactation. At weaning, mice were placed on the control diet and sacrificed at 12 weeks of age. In vitro autoradiography was used to measure mu-opioid receptor (MOR), dopamine type 1 receptor (D1R), and dopamine transporter (DAT) binding level in mesolimbic brain regions. Results showed that the LP offspring (males and females) had significantly higher MOR and D1R binding than the control animals in the regions associated with reward. In HF offspring there were no differences in MOR binding, and limited increases in D1R binding, seen only in females in the nucleus accumbens core and the dorsomedial caudate/putamen. DAT binding revealed no differences in either models. In conclusion, LP but not HF offspring show significantly elevated MOR and D1R binding in the brain thus affecting DA and opioid signaling. These findings advance the current understanding of how suboptimal gestational diets can adversely impact neurodevelopment and increase the risk for disorders such as ADHD, obesity and addiction.

SUN-P236: Effect of Maternal Low Quality Protein Diet on Expression of Hepatic DNA Methyltransferases in Rat Offspring

SUN-P236: Effect of Maternal Low Quality Protein Diet on Expression of Hepatic DNA Methyltransferases in Rat Offspring

Maternal low protein diet leads to placental angiogenic compensation via dysregulated M1/M2 macrophages and TNFα expression in Sprague-Dawley rats

A maternal low-protein (LP) diet in Sprague-Dawley rats results in low birth weight, rapid adipose tissue catch-up growth, adult obesity, and insulin resistance. The placenta functions to fulfill the fetus’ nutrient demands. Adequate angiogenic factor concentrations help to ensure normal growth and vasculature development of the placenta and, in turn, optimum maternal-to-fetal nutrient delivery. Maternal malnutrition creates a proinflammatory environment that leads to inhibition of placental tissue growth. Therefore, we hypothesized that a maternal LP diet will lead to abnormal angiogenesis via dysregulation of immune cells resulting in increased secretion of proinflammatory cytokines and reduced angiogenic factor expression. Sprague-Dawley dams were fed 8% LP or 20% normal protein diets for 3 weeks prior to breeding and throughout pregnancy. Placenta from dams fed a LP diet weighed less; had increased M2 macrophages producing TNFα, decreased M1 macrophages and iNKT cells; greater angiogenic factor (FGF2, VEGFR-1, IGF2) expression and protein content, and greater CD31/PECAM (platelet endothelial cell adhesion molecule) expression. Prenatal protein restriction may induce the placenta to upregulate compensatory mechanisms of angiogenesis in order to meet the nutrient demands of the fetus.

Moderate high or low maternal protein diets change gene expression but not the phenotype of skeletal muscle from porcine fetuses

The aim of our study was to characterize the immediate phenotypic and adaptive regulatory responses of fetuses to different in utero conditions reflecting inadequate maternal protein supply during gestation. The gilts fed high- (250% above control) or low- (50% under control) protein diets isoenergetically adjusted at the expense of carbohydrates from the day of insemination until the fetuses were collected at day 64 or 94 of gestation. We analyzed body composition, histomorphology, biochemistry, and messenger RNA (mRNA) expression of fetal skeletal muscle. Both diets had only marginal effects on body composition and muscular cellularity of fetuses including an unchanged total number of myofibers. However, mRNA expression of myogenic regulatory factors (MYOG, MRF4, P ≤ 0.1), IGF system (IGF1, IGF1R, P ≤ 0.05) and myostatin antagonist FST (P = 0.6, in males only) was reduced in the fetal muscle exposed to a maternal low-protein diet. As a result of excess protein, MYOD, MYOG, IGF1R, and IGFBP5 mRNA expression (P ≤ 0.05) was upregulated in fetal muscle. Differences in muscular mRNA expression indicate in utero regulatory adaptive responses to maternal diet. Modulation of gene expression immediately contributes to the maintenance of an appropriate fetal phenotype that would be similar to that observed in the control fetuses. Moreover, we suggest that the modified gene expression in fetal skeletal muscle can be viewed as the origin of developmental muscular plasticity involved in the concept of fetal programming.