Abstract Increased transport of nutrients such as glucose, across the placenta, has been linked to abnormal fetal growth and pregnancy complications in obese non-diabetic mothers (1); however, the underlying mechanisms are poorly understood. We hypothesized that in placenta, the metabolic and nutrient sensor O-GlcNAc transferase (OGT), highly sensitive to glucose flux through the hexosamine biosynthetic pathway (HBP), responds to maternal obesogenic environment by increasing O-GlcNAc post-translational modification of nucleocytoplasmic proteins in the placenta altering fetal growth trajectories. Tissue biopsies were isolated from placentas collected at term from 26 non-diabetic mothers alongside routine biochemistry and anthropometric data (maternal fasting glucose, glycated hemoglobin (HbA1c), early pregnancy body weight (BMI) and birth weight). OGT and glucose transporter 1 (GLUT1) protein expression as well as tissue levels of O-GlcNAcylation were determined by immunoblotting using specific antibodies. The BeWo choriocarcinoma cell line was also used as an in vitro model of trophoblast to test the effect of high glucose and GLUT1 silencing on the OGT activity by immunoblotting. Maternal BMI was positively correlated to birth weight centile (BWC) (p=0.0130, R2=0.231), maternal fasting glucose (p=0.0177, R2=0.221) and HbA1c levels (p= 0.0156, R2=0.229) as well as placental OGT protein expression (p=0.0294, R2=0.183). The latter was positively associated to the levels of protein O-GlcNAcylation (p=0.0023, R2=0.326). Interestingly, GLUT1 protein levels were positively correlated to BWC (p=0.0056, R2=0.279) and strongly correlated to protein O-GlcNAcylation (p<0.0001, R2=0.507), suggesting an increase in the placental flux of glucose. In agreement with findings in placenta biopsies, in BeWo cells total protein O-GlcNAcylation levels were altered by cell exposure to different glucose levels (5 mM vs 15 mM, p<0.01). This was prevented by downregulating OGT or GLUT1 expression (p<0.001) using gene silencing. In addition, OGT protein levels were negatively associated to AMP-activated protein kinase (AMPK) activation (p=0.0005, R2=0.402) in placenta biopsies identifying a novel cross-talk between two placental nutrient sensors, OGT and AMPK, previously shown in other tissues (2). Accordingly, the silencing of OGT promoted the activation of AMPK (p<0.01) and its downstream target acetyl-CoA carboxylase (ACC) (p<0.01) in BeWo cells, as demonstrated by increased phosphorylation of residues Thr172 and Ser79 for AMPK and ACC respectively. Such obesity-associated cross talk between metabolic and nutrient sensors might disrupt multiple cellular pathways involved in fetal development and growth. References: (1) Acosta et al. Am J Obstet Gynecol. 2015 Feb;212(2):227. (2) Bullen et al. J Biol Chem. 2014 Apr 11;289(15):10592-606.
A growing body of evidence suggests the consumption of high-fat diet (HFD) during pregnancy to model maternal obesity and the associated increase in oxidative stress (OS), might act as powerful prenatal stressors, leading to adult stress-related metabolic or behavioral disorders. We hypothesized that administration of antioxidants throughout gestation might counteract the negative effects of prenatal exposure to metabolic challenges (maternal HFD feeding during pregnancy) on the developing fetus. In this study, female C57BL/6J mice were fed HFD for 13 weeks (from 5-weeks of age until delivery) and were exposed to the N-acetyl-cysteine (NAC) antioxidant from 10-weeks of age until right before delivery. Body weight of the offspring was assessed following birth, up to weaning and at adulthood. The metabolic, neuroendocrine and emotional profile of the adult offspring was tested at 3-months of age. Prenatal HFD increased mother's body weight and offspring's weight at the time of weaning, when administered in conjunction with NAC. In females, NAC administration reduced high levels of leptin resulting from prenatal HFD. Prenatal NAC administration also resulted in greater glucose tolerance and insulin sensitivity while increasing adiponectin levels, as well as increasing exploratory behavior, an effect accompanied by reduced plasma corticosterone levels in response to restraint stress. Analysis of glutathione levels in the hypothalamus and in brown adipose tissue indicates that, while HFD administration to pregnant dams led to reduced levels of glutathione in the offspring, as in the male hypothalamus, NAC was able to revert this effect and to increase glutathione levels both in the periphery (Brown Adipose Tissue, both males and females) and in the central nervous system (males). Overall, results from this study indicate that the body redox milieu should be tightly regulated during fetal life and that buffering OS during pregnancy can have important long-term consequences on metabolic and behavioral endpoints.
Prenatal stress (PNS) might affect the developmental programming of adult chronic diseases such as metabolic and mood disorders. The molecular mechanisms underlying such regulations may rely upon long-term changes in stress-responsive effectors such as Brain-Derived Neurotrophic Factor (BDNF) that can affect neuronal plasticity underlying mood disorders and may also play a role in metabolic regulation. Based upon previous data, we hypothesized that PNS might lead to greater vulnerability to an obesogenic challenge experienced at adulthood. In order to investigate our hypothesis, pregnant Sprague-Dawley female rats underwent a chronic procedure of restraint stress during the last week of gestation. The adult offspring were then challenged with a high fat diet (HFD) over 8 weeks and tested for metabolic and emotional endpoints. Moreover, brain specific changes in Bdnf expression levels were also assessed. Overall, HFD resulted in increased caloric intake, insulin resistance, impaired glucose tolerance and higher circulating levels of leptin, while PNS increased the leptin/adiponectin ratio, an index of metabolic risk in adult male subjects. Interestingly, HFD consumption increased anxiety-like behaviors in the Elevated Plus Maze, particularly in males, and this effect was buffered by PNS. Levels of Bdnf were finely modulated by PNS and HFD in a region- and sex-dependent fashion: female offspring overall showed greater plasticity, possibly mediated through increased total Bdnf mRNA expression both in the hippocampus and in the hypothalamus. In conclusion, while the experience of maternal stress during intrauterine life promotes metabolic dysfunction induced by a HFD at adulthood, the interaction between PNS and HFD is positive in male subjects, and in agreement with the match-mismatch hypothesis, resulting in a reduction of anxious behaviors.
A balanced interaction between the homeostatic mechanisms of mother and the developing organism during pregnancy and in early neonatal life is essential in order to ensure optimal fetal development, ability to respond to various external and internal challenges, protection from adverse programming, and safeguard maternal care availability after parturition. In the majority of pregnancies, this relationship is highly effective resulting in successful outcomes. However, in a number of pathological settings, perturbations of the maternal homeostasis disrupt this symbiosis and initiate adaptive responses with unpredictable outcomes for the fetus or even the neonate. This may lead to development of pathological phenotypes arising from developmental reprogramming involving interaction of genetic, epigenetic, and environmental-driven pathways, sometimes with acute consequences (e.g., growth impairment) and sometimes delayed (e.g., enhanced susceptibility to disease) that last well into adulthood. Most of these adaptive mechanisms are activated and controlled by hormones of the hypothalamo-pituitary adrenal axis under the influence of placental steroid and peptide hormones. In particular, the hypothalamic peptide corticotropin-releasing hormone (CRH) plays a key role in feto-maternal communication by orchestrating and integrating a series of neuroendocrine, immune, metabolic, and behavioral responses. CRH also regulates neural networks involved in maternal behavior and this determines efficiency of maternal care and neonate interactions. This review will summarize our current understanding of CRH actions during the perinatal period, focusing on the physiological roles for both mother and offspring and also how external challenges can alter CRH actions and potentially impact on fetus/neonate health.
Prenatal stress (PNS) is a risk factor for the development of neuropsychiatric disorders. This study was aimed at assessing, in a rodent model, changes in gene expression profiles and behavioral output as a result of PNS, during periadolescence, a critical developmental period for the onset of psychopathology. Social behavior was studied in a standardized social interaction paradigm and the expression of Brain-Derived Neurotrophic Factor (Bdnf), a marker of neuronal plasticity, and of inhibitory and excitatory mechanisms (Na(+)-K(+)-2Cl(-) and K(+)-Cl(-) cotransporters ratio, NKCC1/KCC2) was analyzed. Results indicate that PNS reduced Bdnf transcripts while increasing the NKCC1/KCC2 ratio, primarily in the hippocampus. In the prefrontal cortex, changes in Bdnf were found to be gender-dependent. These effects were accompanied by reduced levels of affiliative and investigative social behaviors. Interestingly, interaction with non-stressed subjects was able to improve sociality in PNS rats suggesting that the social environment could be exploited for therapeutic intervention.
Maternal diet during pregnancy can impact maternal behavior as well as the intrauterine environment, playing a critical role in programming offspring's physiology. In a preliminary study, we found a strong association between high-fat diet (HFD) during pregnancy and increased cannibalistic episodes and dams' mortality during late pregnancy and parturition. Based upon these data, we hypothesized that HFD during pregnancy could negatively affect neuroendocrine and metabolic regulations occurring during the final stages of pregnancy, thereby disrupting maternal behavior. To test this hypothesis, female C57BL/6J mice were fed HFD or control diet for 11 weeks until three days before the expected delivery date. Basal corticosterone plasma levels and brain levels of c-Fos were measured both before and after delivery, in addition to leptin levels in the adipose tissue. Dam's emotional behavior and social anxiety, in addition to locomotor activity were assessed before parturition. Data show that HFD led to aberrant maternal behavior, dams being characterized by behaviors related to aggression toward an unfamiliar social stimulus in the social avoidance test, in addition to decreased locomotor activity. Neural activity in HFD dams was reduced in the olfactory bulbs, a crucial brain region for social and olfactory recognition hence essential for maternal behavior. Furthermore, HFD feeding resulted in increased circulating levels of maternal corticosterone and decreased levels of leptin. In addition, the activity of the protective 11β-dehydrogenase-2 (11β-HSD-2) barrier in the placenta was decreased together with 11β-dehydrogenase-1 (11β-HSD-1) gene expression. Overall, these data suggest that HFD acts as a stressful challenge during pregnancy, impairing the neuroendocrine system and the neural activity of brain regions involved in the processing of relevant olfactory stimuli, with negative consequences on maternal physiology and behavior.
The aim was to localize chemokine ligand twelve (CXCL12) in sheep placental tissues during early gestation and after assisted reproductive technologies (ART). Uteri were collected from naturally (NAT) mated ewes and ewes receiving embryo transfer (ET), in vitro fertilization (IVF) or in vitro activation (IVA). CXCL12 was immunolocalized to endometrial stroma, glands, and trophoblast. Greater CXCL12 immunoreactivity was present in trophoblast on day 22 and 24 and in NAT ewes compared to IVF and IVA. Increased CXCL12 expression suggests CXCL12 promotes implantation and placentation. Decreased CXCL12 in IVF and IVA embryos, may compromise pregnancy establishment when utilizing ART methods.
Children exposed to adverse psychosocial experiences, or early parental loss, are at an increased risk for later depression. Preclinical data indicate that epigenetic regulation of gene expression mediates the effects of early life stress (ELS) on adult behavior and health. In addition to stress-responsive systems (glucocorticoids), the expression of neurotrophic factors in the brain may be regulated epigenetically in the context of ELS contributing to mental health, or systemic disease at adulthood. In order to investigate epigenetic changes in target genes involved in the long-term effects of early adversity on psychopathology, we have set up an animal model (rat) of prenatal stress. show that ELS leads to a long-term down-regulation in the expression of target genes, such as the receptor for glucocorticoids and Brain derived neurotrophic factor (BDNF), thus mimicking adult conditions characterizing increased risk for psychopathology. Behavioral and neuroendocrine changes accompanying these differences in gene expression suggest increased stress responsivity, as well as impaired social behavior. Chronic treatment with the antipsychotic lurasidone during adolescence was able to counteract the changes in BDNF expression produced by ELS, preventing the down-regulation of long 3'-UTR BDNF levels that occurred from late adolescence into young adulthood. Furthermore, interaction with a non-stressed rat conspecific ameliorated behavioural dysfunction. data indicate potential therapeutic targets to counteract prenatal stress and suggest that the perinatal environment can act as a potential buffer for stressful conditions occurring around birth. Support: ERA net-NEURON 'Poseidon" and Fondazione Cariplo 2012.
To explore the interrelationship of two challenging aspects of the cancer experience: the diagnosis and experience of younger women living with multiple myeloma, and their geographical disadvantage.A cross-sectional retrospective qualitative methodology was employed. Five women with dependent children and a diagnosis of myeloma, living in rural and regional Australia, were interviewed using a semi-structured technique. Interpretative phenomenological analysis provided the foundation for the data analysis and interpretation.The central concept of disease isolation emerged from the data and captured the interrelationship of the experience of living with a rare cancer, while living in a rural and regional area of Australia. Three strong themes emerged: 1) isolation due to living with a rare cancer, 2) isolation within the myeloma population, and 3) isolation due to the disease effects and treatment. In the context of these results, isolation depicted the sense of being alone or separated, both physically and psychologically, from potential sources of support, and of being different from others (both patients with cancer and patients with myeloma), which presented barriers to accessing support.The interrelationship of geographical isolation and living with multiple myeloma underpins the core issues relating to the main themes. Understanding the issues confronting younger women with myeloma living in rural and regional of Australia may assist health professionals to improve support for women in this situation.
Metabolic stressful challenges during susceptible time windows, such as fetal life, can have important implications for health throughout life. Deletion of the p66(Shc) gene in mice leads to reduced oxidative stress (OS), resulting in a healthy and lean phenotype characterized by increased metabolic rate, resistance to high-fat diet (HFD)-induced obesity and reduced emotionality at adulthood. Here we hypothesize that p66(Shc-/-) (KO) adult offspring might be protected from the detrimental effects induced by maternal HFD administered before and during pregnancy. To test such hypothesis, we fed p66(Shc+/+) (WT) and KO females with HFD for 13 weeks starting on 5 weeks of age until delivery and tested adult male and female offspring for their metabolic, neuroendocrine, and emotional profile. Prenatal diet affected stress responses and metabolic features in a gender-dependent fashion. In particular, prenatal HFD increased plasma leptin levels and decreased anxiety-like behavior in females, while increasing body weight, particularly in KO subjects. KO mice were overall characterized by metabolic resiliency, showing a blunted change in glycemia levels in response to glucose or insulin challenges. However, in p66(Shc-/-) mice, prenatal HFD affected glucose tolerance response in an opposite manner in the two genders, overriding the resilience in males and exacerbating it in females. Finally, KO females were protected from the disrupting effect of prenatal HFD on neuroendocrine response. These findings indicate that prenatal HFD alters the emotional profile and metabolic functionality of the adult individual in a gender-dependent fashion and suggest that exposure to high-caloric food during fetal life is a stressful condition interfering with the developmental programming of the adult phenotype. Deletion of the p66(Shc) gene attenuates such effects, acting as a protective factor.