Maternal obesity promotes a proinflammatory signature in rat uterus and blastocyst

The Molecular Link between Obesity and the Endometrial Environment: A Starting Point for Female Infertility

Female infertility constitutes a growing health problem in developing countries and could be associated with several possible causes including reproductive disorders, congenital malformations, infections and hormonal dysfunction. Nonetheless, a series of additional factors can also negatively impact female fertility and are represented by chronic exposure to environmental pollutants, stress, unhealthy lifestyle choices such as cigarette smoking and, among others, obesity. Excess weight is associated with several chronic diseases, and growing evidence demonstrates that it can compromise reproductive physiology due to its influence on endometrial gene expression and receptivity. Thus, the current review of the literature mainly focused on how obesity can impair uterine receptivity, mostly from a molecular point of view throughout the window of implantation (WOI) period at an endometrial level. It was also highlighted that an obesity-related increase in adipose tissue may lead to a modulation in the expression of multiple pathways, which could cause a hostile endometrial environment with a consequent negative impact on the uterine receptivity and the establishment of pregnancy. Thanks to the use of the endometrial receptivity assay (ERA), a specific microarray that studies the expression of a series of genes, it is now possible to evaluate the endometrial status of patients with infertility problems in a more detailed manner. Moreover, female fertility and endometrial receptivity could be affected by endometriosis, a chronic benign gynecological disease, whose cause-and-effect relationship to obesity is still uncertain. Therefore, further investigations would be required to better elucidate these mechanisms that govern embryo implantation and could be potentially useful for the generation of new strategies to overcome implantation failure and improve the pregnancy rates in obese women.

Altered DNA methylation and Dnmt expression in obese uterus may cause implantation failure

Obesity is defined by increased adipose tissue volume and has become a major risk factor for reproduction. Recent studies have revealed a substantial link between obesity and epigenetics. The epigenome is dynamically regulated mainly by DNA methylation. DNA methylation, which is controlled by DNA methyltransferases (Dnmts), has been widely studied because it is essential for imprinting and regulation of gene expression. In our previous study, we showed that the levels of Dnmt1, Dnmt3a and global DNA methylation was dramatically altered in the testis and ovary of high-fat diet (HFD)-induced obese mice. However, the effect of HFD on Dnmts and global DNA methylation in mouse uterus has not yet been demonstrated. Therefore, in the present study, we aimed to evaluate the effect of HFD on the level of Dnmt1, Dnmt3a, Dnmt3b, Dnmt3l and global DNA methylation in uterus. Our results showed that HFD significantly altered the levels of Dnmts and global DNA methylation in the uterus. The total expression of Dnmt1, Dnmt3a and Dnmt3b was significantly upregulated, while level of Dnmt3l and global DNA methylation were dramatically decreased (p < 0.05). Furthermore, we observed that the expression of Dnmt3b and Dnmt3l was significantly increased in endometrium including gland and epithelium (p < 0.05). Although Dnmt3b was the only protein whose expression significantly increased, the level of global DNA methylation and Dnmt3l significantly decreased in stroma and myometrium (p < 0.05). In conclusion, our results show for the first time that obesity dramatically alters global DNA methylation and expression of Dnmts, and decreased DNA methylation and Dnmt expression may cause abnormal gene expression, especially in the endometrium.

Salvia officinalis Improves Glycemia and Suppresses Pro-inflammatory Features in Obese Rats with Metabolic Syndrome

OBJECTIVES

Obesity is regarded as the main cause of metabolic diseases and a core factor for all-cause mortality in the general population, notably from cardiovascular disease. The majority of people with type 2 diabetes have obesity and insulin resistance. Some evidence indicates that an individual with obesity is approximately 10 times more likely to develop type 2 diabetes than someone with moderate body weight. One of the most significant therapeutic herbs, Salvia officinalis (Lamiaceae) (SAGE), possesses potent medicinal importance. The aim of this article was to evaluate the anti-diabetic and antiobesity activity of SAGEAE against HFD-induced obesity in rats.

METHODS

Thirty adult albino rats were randomly divided into five equal groups: control, High-fat Diet (HFD) administrated rats, HFD + Salvia officinalis Aqueous Extract (SAGEAE) (150 mg/kg.bw.), HFD + SAGEAE (300 mg/kg.bw.) and HFD + metformin (500 mg/kg.bw.). Body weight, plasma biochemical parameters, oxidative stress, inflammatory indicators, hepatic Phosphoenolpyruvate Carboxykinase 1 (PCK1), Glucokinase (GK), brain Leptin Receptor (LepRb), Glucose Transporter-4 (GLUT4), Sirtuin 1 (SIRT1) and mRNA33-5P gene signalling mRNA levels were all assessed after 8 weeks. A histological examination of the liver was also performed to check for lipid accumulation.

RESULTS

The administration of HFD resulted in increased body weight, glucose, insulin, leptin, Total Cholesterol (TC), Triglycerides (TG), Thiobarbaturic Acid Reactive Substances (TBARS), Monocyte Chemoattractant Protein-1 (MCP1), Interleukine-6 (IL-6) and tumor necrosis factor-α (TNF- α) as well as hepatic PCK1, brain LepRb and adipose tissue mRNA33-5P gene expression. However, our findings revealed a significant reduction in adiponectin, High-density Lipoproteincholesterol (HDL-C), reduced glutathione (GSH) and Superoxide Dismutase (SOD) levels as well as the expression of hepatic GK and adipose tissue SIRT1 and GLUT4 genes. Also, administration of SAGEAE significantly normalized body weight, glucose, insulin, leptin, adiponectin, TC, TG, HDL-C, TBARs, SOD, IL-6, MCP-1 and TNF-α in plasma and liver tissue of HFD-treated rats. On the other hand, PCK1, GK, LepRb, SIRT1, GLUT4 and mRNA33-5P gene expression was enhanced in obese rats when administrated with SAGEAE. Histological and US studies support the biochemical, PCR and electrophoretic results.

CONCLUSION

The findings imply that SAGEAE could be used as a new pharmaceutical formula in the treatment of obesity.

Attention-deficit/hyperactivity disorder and inflammation: natural product-derived treatments-a review of the last ten years

OBJECTIVE

Attention-deficit hyperactivity disorder (ADHD) is a psychiatric disorder characterized by symptoms of inattention, hyperactivity, and impulsivity. Stimulant medication is the main pharmacological treatment for ADHD. However, the traditional pharmacological treatments may have significant side effects; therefore, non-pharmacological approaches are needed. Thus, there has been growing interest in alternative herbal treatments. The aim of this review was to comprehensively assess the current evidence for plant-based treatment of ADHD in human and animal models, as well as their ability to modulate the inflammatory process.

METHODS

This study was an integrative review of the current evidence for the plant-based treatment of ADHD. The research involved using literature available on PubMed and Scopus databases.

FINDINGS

Spontaneously hypersensitive rats treated with baicalin exhibited significant reductions in locomotion, increased spatial learning skills, and increased levels of dopamine in the striatum. Supplementation with Sansonite improved memory and attention capacity. In human studies, Ginkgo biloba significantly improved the symptoms of inattention and reduced memory impairment. In studies conducted using Korean Red ginseng, Klamath, and Crocus sativus L., the patients showed significant improvements in symptoms of inattention and hyperactivity/impulsivity. Furthermore, we demonstrated that the identified plants modulate the inflammatory process through pro-inflammatory and anti-inflammatory cytokines, nitric oxide, Th cells, Toll-like receptor 4, and mitogen-activated protein kinases.

CONCLUSION

All the studies included in this review focused on plants with demonstrated potential against inflammatory processes, positioning them as promising candidates for ADHD treatment, due to their potential to attenuate or even prevent neuroinflammatory mechanisms.

Maternal Exercise Prior to and during Gestation Induces Sex-Specific Alterations in the Mouse Placenta

While exercise (EX) during pregnancy is beneficial for both mother and child, little is known about the mechanisms by which maternal exercise mediates changes in utero. Six-week-old female C57BL/6 mice were divided into two groups: with (exercise, EX; N = 7) or without (sedentary, SED; N = 8) access to voluntary running wheels. EX was provided via 24 h access to wheels for 10 weeks prior to conception until late pregnancy (18.5 days post coitum). Sex-stratified placentas and fetal livers were collected. Microarray analysis of SED and EX placentas revealed that EX affected gene transcript expression of 283 and 661 transcripts in male and female placentas, respectively (±1.4-fold, p < 0.05). Gene Set Enrichment and Ingenuity Pathway Analyses of male placentas showed that EX led to inhibition of signaling pathways, biological functions, and down-regulation of transcripts related to lipid and steroid metabolism, while EX in female placentas led to activation of pathways, biological functions, and gene expression related to muscle growth, brain, vascular development, and growth factors. Overall, our results suggest that the effects of maternal EX on the placenta and presumably on the offspring are sexually dimorphic.

Maternal obesity and high leptin levels prime pro-inflammatory pathways in human cord blood leukocytes

INTRODUCTION

Maternal obesity alters the immune function in the offspring. We hypothesize that maternal obesity and pro-inflammatory pathways induce leptin-related genes in neonatal monocytes, whereby high leptin levels enhance their inflammatory response.

METHODS

Transcriptional profiles of cord blood leukocytes (CBL) in basal and pro-inflammatory conditions were studied to determine differentially expressed genes (DEG). The DNA methylation profile of CB monocytes (CBM) of neonates born to control BMI mothers and women with obesity was assayed to identify differentially methylated probes (DMP). CBM-derived macrophages were cultured with or without leptin (10-100 ng/ml) and then stimulated with lipopolysaccharide (LPS, 100 ng/ml) and interferon-gamma (20 ng/ml) to assess the induction of TNF-α and IL-10 transcripts.

RESULTS

CBL from pregnancies with obesity (CBL-Ob) showed 12,183 DEG, affecting 49 out of 78 from the leptin pathway. Control CBM exposed to LPS showed 45 leptin-related DEG, an effect prevented by the co-exposure to LPS and IL-10. Conversely, CBM-Ob showed 5279 DMP enriched in insulin- and leptin-related genes, and Lasso regression of leptin-related DMP showed high predictive value for plasma leptin levels (r2 = 0.9897) and maternal BMI categories (AUC = 1). Chronic exposure to leptin increased TNF-α and decreased IL-10 levels in control BMI samples but not in Ob-CBM. Enhanced TNF-α induction after proinflammatory stimulation was observed in leptin-treated control BMI samples.

DISCUSSION

Obesity in pregnancy is associated with a distinctive expression and DNA methylation profile of leptin-related genes in cord blood monocytes, meanwhile, leptin enhances the expression of pro-inflammatory cytokines upon stimulation with M1-skewing agents.

Nutrition and Developmental Origins of Kidney Disease

The developmental programming hypothesis proposes that adverse environmental insults during critical developmental periods increase the risk of diseases later in life. The kidneys are deemed susceptible to such a process, although the exact mechanisms remain elusive. Many factors have been reported to contribute to the developmental origin of chronic kidney diseases (CKD), among which peri-gestational nutrition has a central role, affecting kidney development and metabolism. Physiologically, the link between malnutrition, reduced glomerular numbers, and increased blood pressure is key in the developmental programming of CKD. However, recent studies regarding oxidative stress, mitochondrial dysfunction, epigenetic modifications, and metabolic changes have revealed potential novel pathways for therapeutic intervention. This review will discuss the role of imbalanced nutrition in the development of CKD.

Emerging role of hypothalamus in the metabolic regulation in the offspring of maternal obesity

Maternal obesity has a significant impact on the metabolism of offspring both in childhood and adulthood. The metabolic regulation of offspring is influenced by the intrauterine metabolic programming induced by maternal obesity. Nevertheless, the precise mechanisms remain unclear. The hypothalamus is the primary target of metabolic programming and the principal regulatory center of energy metabolism. Accumulating evidence has indicated the crucial role of hypothalamic regulation in the metabolism of offspring exposed to maternal obesity. This article reviews the development of hypothalamus, the role of the hypothalamic regulations in energy homeostasis, possible mechanisms underlying the developmental programming of energy metabolism in offspring, and the potential therapeutic approaches for preventing metabolic diseases later in life. Lastly, we discuss the challenges and future directions of hypothalamic regulation in the metabolism of children born to obese mothers.

The physiology of experimental overfeeding in animals

BACKGROUND

Body weight is defended by strong homeostatic forces. Several of the key biological mechanisms that counteract weight loss have been unraveled over the last decades. In contrast, the mechanisms that protect body weight and fat mass from becoming too high remain largely unknown. Understanding this aspect of energy balance regulation holds great promise for curbing the obesity epidemic. Decoding the physiological and molecular pathways that defend against weight gain can be achieved by an intervention referred to as 'experimental overfeeding'.

SCOPE OF THE REVIEW

In this review, we define experimental overfeeding and summarize the studies that have been conducted on animals. This field of research shows that experimental overfeeding induces a potent and prolonged hypophagic response that seems to be conserved across species and mediated by unidentified endocrine factors. In addition, the literature shows that experimental overfeeding can be used to model the development of non-alcoholic steatohepatitis and that forced intragastric infusion of surplus calories lowers survival from infections. Finally, we highlight studies indicating that experimental overfeeding can be employed to study the transgenerational effects of a positive energy balance and how dietary composition and macronutrient content might impact energy homeostasis and obesity development in animals.

MAJOR CONCLUSIONS

Experimental overfeeding of animals is a powerful yet underappreciated method to investigate the defense mechanisms against weight gain. This intervention also represents an alternative approach for studying the pathophysiology of metabolic liver diseases and the links between energy balance and infection biology. Future research in this field could help uncover why humans respond differently to an obesogenic environment and reveal novel pathways with therapeutic potential against obesity and cardiometabolic disorders.

Breastfeeding duration modifies the association between maternal weight status and offspring dietary palmitate oxidation

BACKGROUND

Offspring of obese rodents develop a metabolic phenotype that favors fat deposition. Data regarding the impact of maternal obesity programing of offspring fuel usage in humans is scarce.

OBJECTIVE

The objective of this study was to explore the association between maternal weight status and dietary palmitate oxidation (DPO) in 2-y-old offspring, taking into consideration potential confounders and modifiers.

METHODS

Women (n = 56) were enrolled by the first trimester of gestation. Maternal physical activity (PA; measured with accelerometers) at enrollment and gestational weight gain (GWG) were measured. Offspring sex, race, and breastfeeding (BF) duration were self-reported. Human milk (HM) composition was determined at 6 mo postpartum. At age 2 y, dietary quality [healthy eating index (HEI)] and parental feeding practices [Child Feeding Questionnaire (CFQ)] were assessed. DPO in 2-y-olds (2-yo-DPO) was measured using deuterated palmitic acid. Generalized linear regression analysis was used to model the associations of 2-yo-DPO with maternal weight status [normal weight (NW), BMI <25 (in kg/m2) compared with excessive weight (EW), BMI ≥25].

RESULTS

DPO was higher in offspring of women with EW compared with NW (2.1 ± 1.2%/h compared with 1.4 ± 0.7%/h, P = 0.03). Maternal weight status interacted with BF duration in association with 2-yo-DPO (log ß: 0.05, P = 0.04). Specifically, 2-yo-DPO was higher in the EW compared with NW group if BF duration was ≥9 mo. HM insulin (log ß: 0.35, P = 0.002) and HM leptin (log ß: 0.81, P = 0.001) concentrations directly associated with 2-yo-DPO. PA (log ß: 0.06, P = 0.013), parental feeding restriction (log ß: 0.05, P < 0.0001), and male sex (log ß: 0.54, P < 0.001) were positively associated with 2-yo-DPO. HEI was negatively associated with 2-yo-DPO (log ß:-0.03, P < 0.0001).

CONCLUSIONS

Higher 2-yo-DPO in offspring of women with EW compared with NW were driven by BF duration. Higher HM insulin and leptin concentrations in women with EW may explain these finding. More studies are needed to confirm these results. This trial was registered at clinicaltrials.gov as NCT03281850.

Fat augments leptin-induced uterine contractions by decreasing JAK2 and BKCa channel expressions in late pregnant rats

Altered lipid metabolism in obesity causes pregnancy complications in humans and animals. Leptin levels increase in pregnancy, as well as obesity. However, the effect of obesity on uterine leptin receptors and its distal signaling is not clear. The present study aimed to understand the effect of increased fat on leptin signaling in rat uterus. Wistar female rats were fed with an HF diet (40% Fat, 17% Sucrose, 1.25% Cholesterol, 0.75% Cholic acid) for 6 weeks before the mating and during pregnancy. HF diet significantly increased the fat depots, liver weight, serum, and tissue cholesterol levels. It produced fatty degeneration in the liver and caused infiltration of inflammatory cells, cystic endometrial glands, and sub endometrial fibrosis of the uterus. In isometric tension experiments, leptin caused a significant increase in uterine contractions in high fat-fed animals compared to control animals. Analysis of receptor expressions revealed no significant difference between the groups. However, a significant decrease in the JAK2 and BKCaα mRNA expression was observed in the uterus of high fat-fed rats. No change in the BKCaβ, eNOS, iNOS, MLCP, and MLCK mRNA expressions was noticed in the HF group compared to the control. The findings of the present study suggest that the contractile response to leptin in the uterus of high fat-fed rats may be attributed to reduced signaling through JAK2 and, lowered expressions of BKCa channel α subunits.

Influence of maternal obesity on the multi-omics profiles of the maternal body, gestational tissue, and offspring

Epidemiological studies show that obesity during pregnancy affects more than half of the pregnancies in the developed countries and is associated with obstetric problems and poor outcomes. Obesity tends to increase the incidence of complications. Furthermore, the resulting offspring are also adversely affected. However, the molecular mechanisms of obesity leading to poor pregnancy outcomes remain unclear. Omics methods are used for genetic diagnosis and marker discovery. The aim of this review was to summarize the maternal and fetal pathophysiological alterations induced by gestational obesity,identified using multi-omics detection techniques, and to generalize the biological functions and potential mechanisms of the differentially expressed molecules.

Short Communication: Maternal obesity alters ovine endometrial gene expression during peri-implantation development

Exposure to maternal obesity in utero is associated with marked developmental effects in offspring that may not be evident until adulthood. Mechanisms regulating the programming effects of maternal obesity on fetal development have been reported, but little is known about how maternal obesity affects the earliest periods of embryonic development. This work explored how obesity influences endometrial gene expression during the peri-implantation period using a sheep model. Ewes were assigned randomly to diets that produced an obese state or maintained a lean state. After 4 mo, obese and lean ewes were bred and then euthanized at day 14 post-breeding. The uterus was excised, conceptuses were flushed, and endometrial tissue was collected. Isolated RNA from endometrial tissues (n = 6 ewes/treatment) were sequenced using an Illumina-based platform. Reads were mapped to the Ovis aries genome (Oar_4.0). Differential gene expression was determined, and results were filtered (false discovery rate ≤ 0.05 and ≥2-fold change, ≥0.2 reads/kilobase/million reads). Differentially expressed genes (DEGs) were identified (n = 699), with 171 downregulated and 498 upregulated in obese vs. lean endometrium, respectively. The most pronounced gene ontology categories identified were cellular process, metabolic process, and biological regulation. Enrichments were detected within the DEGs for genes involved with immune system processes, negative regulation of apoptosis, cell growth, and cell adhesion. A literature search revealed that 125 DEGs were associated with either the trophoblast lineage or the placenta. Genes within this grouping were involved with wingless/integrated signaling, angiogenesis, and integrin signaling. In summary, these data indicate that the peri-implantation endometrium is responsive to maternal obesity. Transcript profile analyses suggest that the endometrial immune response, adhesion, and angiogenesis may be especially susceptible to obesity. Thus, alterations in uterine transcript profiles during early embryogenesis may be a mechanism responsible for developmental programming following maternal obesity exposure in utero.

Prepare Randomized Clinical Trial: Acceptability, Engagement, and Lifestyle Effects of a Weight Loss Intervention Beginning in Pre‐pregnancy

Background

Healthier lifestyles in early pregnancy are associated with lower rates of pregnancy complications, childhood adiposity, and maternal and child cardiovascular risks. However, it is not known whether lifestyle coaching initiated prior to pregnancy can affect behavior and attitudes during pregnancy.

Methods

Three hundred and twenty six women planning pregnancy within 2 years with BMI ≥27 kg/m² were randomized to a behavioral weight loss intervention or to usual care. Analyses reported here examined the intervention’s impact on mid‐pregnancy diet quality and activity levels; program acceptability; and effects of pregnancy on intervention engagement.

Results

One hundred and sixty eight participants experienced pregnancy during the study (intervention: 91; usual care: 77). From randomization to mid‐pregnancy, participants who received the intervention had larger increases in fruit intake than usual care participants (+0.67 vs. +0.06 cups; p = 0.02) and engaged in more vigorous‐intensity activity (3.9 [5.5] vs. 1.2 [3.0] Met‐hr/week p = 0.002) and sports/exercise (17.0 [14.1] vs. 11.0 [9.5] Met‐hr/week; p = 0.03); the groups also differed in changes in sedentary time (−4.9 [15.0] vs. +0.5 [7.6] Met‐hr/week; p = 0.02). Intervention satisfaction was high (>80%), and experiencing pregnancy during the intervention was associated with higher engagement.

Conclusion

A coaching‐based intervention beginning in pre‐pregnancy successfully helped women attain healthier diet and exercise habits in mid‐pregnancy.

Clinical trials registration

Registered with ClinicalTrials.gov, NCT02346162, first registered on January 26, 2015, before date of initial participant enrollment (May 2015), https://clinicaltrials.gov/ct2/show/NCT02346162.

Effects of various calcium transporters on mitochondrial Ca2+ changes and oocyte maturation

Ca2+ participates in many important cellular processes, but the underlying mechanisms are still poorly understood, especially during oocyte maturation. First, we confirmed that calcium in the culture medium was essential for oocyte maturation. Next, various inhibitors of Ca2+ channels were applied to investigate their roles in mitochondrial Ca2+ changes and oocyte maturation. Our results showed that Trmp7, Orai, T-type Ca2+ channels and Na+ /Ca2+ exchanger complex (NCLX) were important for oocyte maturation. Trmp7 inhibition delayed germinal vesicle breakdown. Orai and NCLX inhibition significantly weakened the distribution of mitochondrial Ca2+ around the nucleus compared to the Ctrl group. Interestingly, even T-type Ca2+ channels-specific inhibitor Mibefradil blocked germinal vesicle breakdown; mitochondrial Ca2+ surrounding the nucleus still was maintained at a high level without spindle formation. Two calcium transporter inhibitors, Thapsigargin and Ruthenium Red, which have been confirmed to inhibit oocyte activation, did not significantly affect oocyte maturation. Increasing the knowledge of calcium transport may provide a basis to build on for improving oocyte in vitro maturation in human assisted reproduction clinics.

Analysis of the transcriptome of bovine endometrial cells isolated by laser micro-dissection (2): impacts of post-partum negative energy balance on stromal, glandular and luminal epithelial cells

BACKGROUND

In post-partum dairy cows, the energy needs to satisfy high milk production induces a status of more or less pronounced Negative Energy Balance (NEB). NEB associated with fat mobilization impairs reproductive function. In a companion paper, we described constitutive gene expression in the three main endometrial cell types (stromal, glandular and luminal epithelial cells) isolated by laser capture micro-dissection (LCM) showing the specificities of their transcriptomic profiles. This study investigates the specific impact of NEB on gene expression in these cells around 80 days after parturition at day 15 of the oestrus cycle and describes their specific response to NEB.

RESULTS

Following the description of their constitutive expression, the transcriptome profiles obtained by RNA sequencing of the three cells types revealed that differences related to the severity of NEB altered mainly specific patterns of expression related to individual cell types. Number of differentially expressed genes between severe NEB (SNEB) and mild NEB (MNEB) cows was higher in ST than in LE and GE, respectively. SNEB was associated with differential expression of genes coding for proteins involved in metabolic processes and embryo-maternal interactions in ST. Under-expression of genes encoding proteins with functions related to cell structure was found in GE whereas genes encoding proteins participating in pro-inflammatory pathways were over-expressed. Genes associated to adaptive immunity were under-expressed in LE.

CONCLUSION

The severity of NEB after calving is associated with changes in gene expression around 80 days after parturition corresponding to the time of breeding. Specific alterations in GEs are associated with activation of pro-inflammatory mechanisms. Concomitantly, changes in the expression of genes encoding proteins involved in cell interactions and maternal recognition of pregnancy takes place in ST. The combination of these effects possibly altering the uterine environment and embryo maternal interactions may negatively influence the establishment of pregnancy.

Mitochondrial Ca2 + Is Related to Mitochondrial Activity and Dynamic Events in Mouse Oocytes

Mitochondrial energy insufficiency is strongly associated with oocyte activation disorders. Ca²⁺, especially that in the mitochondrial matrix, plays a pivotal role in mitochondrial energy supplementation, but the underlying mechanisms are still only poorly understood. An encoded mitochondrial matrix Ca²⁺ probe (Mt-GCaMP6s) was introduced to observe mitochondrial Ca²⁺ ([Ca²⁺]_m) dynamic changes during oocyte maturation and activation. We found that active mitochondria surrounding the nucleus showed a higher [Ca²⁺]_m than those distributed in the cortex during oocyte maturation. During oocyte partheno-activation, the patterns of Ca²⁺ dynamic changes were synchronous in the cytoplasm and mitochondria. Such higher concentration of mitochondrial matrix Ca²⁺ was closely related to the distribution of mitochondrial calcium uptake (MICU) protein. We further showed that higher [Ca²⁺]_m mitochondria around the chromosomes in oocytes might have a potential role in stimulating mitochondrial energy for calmodulin-responsive oocyte spindle formation, while synchronizing Ca²⁺ functions in the cytoplasm and nuclear area are important for oocyte activation.

Regulation of [Ca2+]i oscillations and mitochondrial activity by various calcium transporters in mouse oocytes

Oocyte activation inefficiency is one of the reasons for female infertility and Ca²⁺ functions play a critical role in the regulation of oocyte activation. We used various inhibitors of Ca²⁺ channels located on the membrane, including sarcoplasmic/ endoplasmic reticulum Ca²⁺ATPases (SERCAs, the main Ca²⁺ pumps which decrease the intracellular Ca²⁺ level by refilling Ca²⁺ into the sarcoplasmic reticulum), transient receptor potential (TRP) ion channel subfamily member 7 (TRPM7, a Ca²⁺/Mg²⁺-permeable non-selective cation channel), T-type Ca²⁺ channels and calcium channel Orai1, to investigate their roles in [Ca²⁺]_i oscillation patterns and mitochondrial membrane potential during oocyte activation by real-time recording. Our results showed that SERCAs, TRPM7 and T-type Ca²⁺ channels were important for initiation and maintenance of [Ca²⁺]_i oscillations, which was required for mitochondrial membrane potential elevation during oocyte activation, as well as oocyte cytoskeleton stability and subsequent embryo development. Increasing the knowledge of calcium transport may provide a theoretical basis for improving oocyte activation in human assisted reproduction clinics.

Effects of mitochondria-associated Ca2+ transporters suppression on oocyte activation

Oocyte activation deficiency leads to female infertility. [Ca²⁺ ]_i oscillations are required for mitochondrial energy supplement transition from the resting to the excited state, but the underlying mechanisms are still very little known. Three mitochondrial Ca²⁺ channels, Mitochondria Calcium Uniporter (MCU), Na⁺ /Ca²⁺ Exchanger (NCLX) and Voltage-dependent Ca²⁺ Channel (VDAC), were deactivated by inhibitors RU360, CGP37157 and Erastin, respectively. Both Erastin and CGP37157 inhibited mitochondrial activity significantly while attenuating [Ca²⁺ ]_i and [Ca²⁺ ]_m oscillations, which caused developmental block of pronuclear formation. Thus, NCLX and VDAC are two mitochondria-associated Ca²⁺ transporter proteins regulating oocyte activation, which may be used as potential targets to treat female infertility. SIGNIFICANCE OF THE STUDY: NCLX and VDAC are two mitochondria-associated Ca²⁺ transporter proteins regulating oocyte activation.

Maternal Obesity and Western-Style Diet Impair Fetal and Juvenile Offspring Skeletal Muscle Insulin-Stimulated Glucose Transport in Nonhuman Primates

Infants born to mothers with obesity have a greater risk for childhood obesity and metabolic diseases; however, the underlying biological mechanisms remain poorly understood. We used a Japanese macaque model to investigate whether maternal obesity combined with a Western-style diet (WSD) impairs offspring muscle insulin action. Adult females were fed a control or WSD prior to and during pregnancy through lactation, and offspring subsequently weaned to a control or WSD. Muscle glucose uptake and signaling were measured ex vivo in fetal (n = 5-8/group) and juvenile (n = 8/group) offspring. In vivo signaling was evaluated after an insulin bolus just prior to weaning (n = 4-5/group). Maternal WSD reduced insulin-stimulated glucose uptake and impaired insulin signaling at the level of Akt phosphorylation in fetal muscle. In juvenile offspring, insulin-stimulated glucose uptake was similarly reduced by both maternal and postweaning WSD and corresponded to modest reductions in insulin-stimulated Akt phosphorylation relative to controls. We conclude that maternal WSD leads to a persistent decrease in offspring muscle insulin-stimulated glucose uptake even in the absence of increased offspring adiposity or markers of systemic insulin resistance. Switching offspring to a healthy diet did not reverse the effects of maternal WSD on muscle insulin action, suggesting earlier interventions may be warranted.

Developmental programming of mitochondrial biology: a conceptual framework and review

Research on mechanisms underlying the phenomenon of developmental programming of health and disease has focused primarily on processes that are specific to cell types, organs and phenotypes of interest. However, the observation that exposure to suboptimal or adverse developmental conditions concomitantly influences a broad range of phenotypes suggests that these exposures may additionally exert effects through cellular mechanisms that are common, or shared, across these different cell and tissue types. It is in this context that we focus on cellular bioenergetics and propose that mitochondria, bioenergetic and signalling organelles, may represent a key cellular target underlying developmental programming. In this review, we discuss empirical findings in animals and humans that suggest that key structural and functional features of mitochondrial biology exhibit developmental plasticity, and are influenced by the same physiological pathways that are implicated in susceptibility for complex, common age-related disorders, and that these targets of mitochondrial developmental programming exhibit long-term temporal stability. We conclude by articulating current knowledge gaps and propose future research directions to bridge these gaps.

Role of the NLRP3 Inflammasome in Preeclampsia

Reproduction involves tightly regulated series of events and the immune system is involved in an array of reproductive processes. Disruption of well-controlled immune functions leads to infertility, placental inflammation, and numerous pregnancy complications, including preeclampsia (PE). Inflammasomes are involved in the process of pathogen clearance and sterile inflammation. They are large multi-protein complexes that are located in the cytosol and play key roles in the production of the pivotal inflammatory cytokines, interleukin (IL)-1β and IL-18, and pyroptosis. The nucleotide-binding oligomerization domain, leucine-rich repeat-, and pyrin domain-containing 3 (NLRP3) inflammasome is a key mediator of sterile inflammation induced by various types of damage-associated molecular patterns (DAMPs). Recent evidence indicates that the NLRP3 inflammasome is involved in pregnancy dysfunction, including PE. Many DAMPs (uric acid, palmitic acid, high-mobility group box 1, advanced glycation end products, extracellular vesicles, cell-free DNA, and free fatty acids) are increased and associated with pregnancy complications, especially PE. This review focuses on the role of the NLRP3 inflammasome in the pathophysiology of PE.

Oxidative Stress and Inflammation in Sows with Excess Backfat: Up-Regulated Cytokine Expression and Elevated Oxidative Stress Biomarkers in Placenta

Simple Summary

Maternal obesity is associated with increased farrowing difficulties and influences the fetus, but the effect on placental inflammation, oxidative stress, and vascular development in swine remains unclear. In this study, we tested the hypothesis that maternal obesity blocks placental vascular development associated with maternal obesity-increased placental inflammation and oxidative stress in swine. The objective of this study was to evaluate the influence of body condition of sows to placental pro-inflammatory and oxidative stress status and placental angiogenesis. we found that higher backfat thickness in sows is associated with enhanced oxidative stress, increased expression of pro-inflammation cytokines, and inhibited angiogenesis in the placenta. Therefore, reasonable control of body conditions during reproductive cycles may improve placenta development and maintain a healthy placenta environment.

Abstract

In sows, excess backfat during late gestation is associated with increased farrowing difficulties and influences the fetus, but the impact of backfat thickness on placental inflammation, oxidative stress, and vascular development has not been defined. In this study, 120 sows were divided into six groups based on backfat thickness (≤16, 17–18, 19–20, 21–22, 23–24, and ≥25 mm) in late gestation. The placental lipids, reactive oxygen species (ROS), malondialdehyde (MDA), and total antioxidant capacity (TAC) levels, inflammatory-related cytokine and angiogenesis were determined. The concentrations of triglycerides, total cholesterol, low density lipoprotein cholesterol (LDL–C), and free fatty acid (FFA) linearly increased (p < 0.05) associated with increased late gestation backfat. ROS and MDA increased and TAC decreased (p < 0.05) as the backfat thickness increased. The mRNA expression of toll-like receptors (TLR) 2, TLR4, tumor necrosis factor (TNF) α, interleukin (IL)–1β, IL–6, and monocyte chemoattractant protein (MCP)–1 increased with increased backfat in late gestation. There were no differences in IL–8 and IL–10 mRNA expression among sows with different backfat thickness. Placental vessel density initially increased and then decreased with increasing backfat thickness of sows. Similarly, the mRNA levels of vascular endothelial growth factor (VEGF) were also increased and then decreased. Excessive backfat in late gestation was associated with greater oxidative stress, greater expression of proinflammatory cytokines, and decreased expression of placental angiogenic regulators.

Elevated non-esterified fatty acids impair survival and promote lipid accumulation and pro-inflammatory cytokine production in bovine endometrial epithelial cells

Elevated non-esterified fatty acids (NEFAs) are associated with negative effects on bovine theca, granulosa and oviductal cells but the effects of NEFAs on bovine endometrial epithelial cells (bEECs) are not as well documented. The objective of this study was to define the effects of NEFAs on bEECs. Postprimary bEECs were treated with 150, 300 or 500µM of either palmitic acid (PA), stearic acid (SA) or oleic acid (OA) or a mixture of NEFAs (150µM of each FA) or 0.5% final concentration of vehicle ethanol (control). Viability and proliferation of bEECs exposed to 150µM of each NEFA or a mixture of NEFAs were unaffected. Increased lipid accumulation was found in all treated groups (P<0.01). In cells exposed to 500µM of each NEFA and 300µM PA decreased cell viability (P<0.001), proliferation (P<0.05) and increased apoptosis (P<0.05) were observed. Treatment with 500µM OA, PA and SA had the strongest effects on cell viability, proliferation and apoptosis (P<0.05). Treatment with PA and OA increased interleukin-6 (IL-6) concentrations (P<0.05), whereas only the highest concentration of PA, OA and SA stimulated IL-8 production (P<0.05). These results suggest that high concentrations of NEFAs may impair endometrial function with more or less pronounced effects depending on the type of NEFA and time of exposure.

Obesity in mares promotes uterine inflammation and alters embryo lipid fingerprints and homeostasis

Maternal body composition can be an important determinant for development of obesity and metabolic syndrome in adult offspring. Obesity-related outcomes in offspring may include epigenetic alterations; however, mechanisms of fetal programming remain to be fully elucidated. This study was conducted to determine the impact of maternal obesity in the absence of a high fat diet on equine endometrium and preimplantation embryos. Embryos were collected from normal and obese mares at 8 and 16 days and a uterine biopsy at 16 days (0 day = ovulation). With the exception of 8 day embryos, each sample was divided into two pieces. One piece was analyzed for gene expression markers related to carbohydrate metabolism, lipid homeostasis, inflammation, endoplasmic reticulum stress, oxidative stress, mitochondrial stress, and components of the insulin-like growth factor (IGF) system. The second piece was analyzed for lipid content using matrix-assisted laser desorption/ionization mass spectrometry. Obese mares had elevated concentrations of insulin, leptin, and total cholesterol, and they tended to have increased triglycerides and decreased insulin sensitivity. Embryos from obese mares had altered transcript abundance in genes for inflammation and lipid homeostasis, as well as endoplasmic reticulum, oxidative and mitochondrial stress and altered lipid fingerprints. Endometrium from obese mares had increased expression of inflammatory cytokines, lipid homeostasis regulation, mitochondrial stress, and the IGF2 system. This study demonstrates that increased adiposity in mares alters the uterine environment, transcript abundance of genes for cellular functions, and lipid profiles of embryos. These alterations could affect prenatal programming, with potential long-term effects in offspring.

Impact of pregravid obesity on maternal and fetal immunity: Fertile grounds for reprogramming

Maternal pregravid obesity results in several adverse health outcomes during pregnancy, including increased risk of gestational diabetes, preeclampsia, placental abruption, and complications at delivery. Additionally, pregravid obesity and in utero exposure to high fat diet have been shown to have detrimental effects on fetal programming, predisposing the offspring to adverse cardiometabolic, endocrine, and neurodevelopmental outcomes. More recently, a deeper appreciation for the modulation of offspring immunity and infectious disease-related outcomes by maternal pregravid obesity has emerged. This review will describe currently available animal models for studying the impact of maternal pregravid obesity on fetal immunity and review the data from clinical and animal model studies. We also examine the burden of pregravid obesity on the maternal-fetal interface and the link between placental and systemic inflammation. Finally, we discuss future studies needed to identify key mechanistic underpinnings that link maternal inflammatory changes and fetal cellular reprogramming events.

Neuroinflammation as a risk factor for attention deficit hyperactivity disorder

Attention Deficit Hyperactivity Disorder (ADHD) is a persistent, and impairing pediatric-onset neurodevelopmental condition. Its high prevalence, and recurrent controversy over its widespread identification and treatment, drive strong interest in its etiology and mechanisms. Emerging evidence for a role for neuroinflammation in ADHD pathophysiology is of great interest. This evidence includes 1) the above-chance comorbidity of ADHD with inflammatory and autoimmune disorders, 2) initial studies indicating an association with ADHD and increased serum cytokines, 3) preliminary evidence from genetic studies demonstrating associations between polymorphisms in genes associated with inflammatory pathways and ADHD, 4) emerging evidence that early life exposure to environmental factors may increase risk for ADHD via an inflammatory mechanism, and 5) mechanistic evidence from animal models of maternal immune activation documenting behavioral and neural outcomes consistent with ADHD. Prenatal exposure to inflammation is associated with changes in offspring brain development including reductions in cortical gray matter volume and the volume of certain cortical areas -parallel to observations associated with ADHD. Alterations in neurotransmitter systems, including the dopaminergic, serotonergic and glutamatergic systems, are observed in ADHD populations. Animal models provide strong evidence that development and function of these neurotransmitters systems are sensitive to exposure to in utero inflammation. In summary, accumulating evidence from human studies and animal models, while still incomplete, support a potential role for neuroinflammation in the pathophysiology of ADHD. Confirmation of this association and the underlying mechanisms have become valuable targets for research. If confirmed, such a picture may be important in opening new intervention routes.

Transgenerational transmission of hedonic behaviors and metabolic phenotypes induced by maternal overnutrition

Maternal overnutrition has been associated with increased susceptibility to develop obesity and neurological disorders later in life. Most epidemiological as well as experimental studies have focused on the metabolic consequences across generations following an early developmental nutritional insult. Recently, it has been shown that maternal high-fat diet (HFD) affects third-generation female body mass via the paternal lineage. We showed here that the offspring born to HFD ancestors displayed addictive-like behaviors as well as obesity and insulin resistance up to the third generation in the absence of any further exposure to HFD. These findings, implicate that the male germ line is a major player in transferring phenotypic traits. These behavioral and physiological alterations were paralleled by reduced striatal dopamine levels and increased dopamine 2 receptor density. Interestingly, by the third generation a clear gender segregation emerged, where females showed addictive-like behaviors while male HFD offspring showed an obesogenic phenotype. However, methylome profiling of F1 and F2 sperm revealed no significant difference between the offspring groups, suggesting that the sperm methylome might not be the major carrier for the transmission of the phenotypes observed in our mouse model. Together, our study for the first time demonstrates that maternal HFD insult causes sustained alterations of the mesolimbic dopaminergic system suggestive of a predisposition to develop obesity and addictive-like behaviors across multiple generations.

Exposure to maternal obesity alters gene expression in the preimplantation ovine conceptus

Background

Embryonic and fetal exposure to maternal obesity causes several maladaptive morphological and epigenetic changes in exposed offspring. The timing of these events is unclear, but changes can be observed even after a short exposure to maternal obesity around the time of conception. The hypothesis of this work is that maternal obesity influences the ovine preimplantation conceptus early in pregnancy, and this exposure will affect gene expression in embryonic and extraembryonic tissues.

Results

Obese and lean ewe groups were established by overfeeding or normal feeding, respectively. Ewes were then bred to genetically similar rams. Conceptuses were collected at day 14 of gestation. Morphological assessments were made, conceptuses were sexed by genomic PCR analysis, and samples underwent RNA-sequencing analysis. While no obvious morphological differences existed between conceptuses, differentially expressed genes (≥ 2-fold; ≥ 0.2 RPKM; ≤ 0.05 FDR) were detected based on maternal obesity exposure (n = 21). Also, differential effects of maternal obesity were noted on each conceptus sex (n = 347). A large portion of differentially expressed genes were associated with embryogenesis and placental development.

Conclusions

Findings reveal that the preimplantation ovine conceptus genome responds to maternal obesity in a sex-dependent manner. The sexual dimorphism in response to the maternal environment coupled with changes in placental gene expression may explain aberrations in phenotype observed in offspring derived from obese females.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-5120-0) contains supplementary material, which is available to authorized users.

Liver X Receptors: A Possible Link between Lipid Disorders and Female Infertility

A close relationship exists between cholesterol and female reproductive physiology. Indeed, cholesterol is crucial for steroid synthesis by ovary and placenta, and primordial for cell structure during folliculogenesis. Furthermore, oxysterols, cholesterol-derived ligands, play a potential role in oocyte maturation. Anomalies of cholesterol metabolism are frequently linked to infertility. However, little is known about the molecular mechanisms. In parallel, increasing evidence describing the biological roles of liver X receptors (LXRs) in the regulation of steroid synthesis and inflammation, two processes necessary for follicle maturation and ovulation. Both of the isoforms of LXRs and their bona fide ligands are present in the ovary. LXR-deficient mice develop late sterility due to abnormal oocyte maturation and increased oocyte atresia. These mice also have an ovarian hyper stimulation syndrome in response to gonadotropin stimulation. Hence, further studies are necessary to explore their specific roles in oocyte, granulosa, and theca cells. LXRs also modulate estrogen signaling and this could explain the putative protective role of the LXRs in breast cancer growth. Altogether, clinical studies would be important for determining the physiological relevance of LXRs in reproductive disorders in women.

Mitochondrial regulation of [Ca2+]i oscillations during cell cycle resumption of the second meiosis of oocyte

Oocyte is arrested at metaphase of the second meiosis until fertilization switching on [Ca²⁺]i oscillations. Oocyte activation inefficiency is the most challenging problem for failed fertilization and embryonic development. Mitochondrial function and intracellular [Ca²⁺]i oscillations are two critical factors for the oocyte's developmental potential. We aimed to understand the possible correlation between mitochondrial function and [Ca²⁺]i oscillations in oocytes. To this end, mitochondrial uncoupler CCCP which damages mitochondrial function and two small molecule mitochondrial agonists, L-carnitine (LC) and BGP-15, were used to examine the regulation of [Ca²⁺]i by mitochondrial functions. With increasing CCCP concentrations, [Ca²⁺]i oscillations were gradually diminished and high concentrations of CCCP led to oocyte death. LC enhanced mitochondrial membrane potential and [Ca²⁺]i oscillations and even improved the damage induced by CCCP, however, BGP-15 had no beneficial effect on oocyte activation. We have found that mitochondrial function plays a vital role in the generation of [Ca²⁺]i oscillations in oocytes, and thus mitochondria may interact with the ER to generate [Ca²⁺]i oscillations during oocyte activation. Improvement of mitochondrial functions with small molecules can be expected to improve oocyte activation and embryonic development in infertile patients without invasive micromanipulation.

Review shows that maternal obesity induces serious adverse neonatal effects and is associated with childhood obesity in their offspring

AIM

Obesity at the start of pregnancy has been rising worldwide, increasing the risk of maternal complications. We reviewed the independent effects of maternal obesity during pregnancy on neonatal adverse outcomes and the risk of childhood obesity and adverse cardio-metabolic profiles.

METHODS

We searched MEDLINE for papers published in English between December 2007 and November 2017, focusing primarily on human studies published in the last five years. However, we also chose to highlight examples derived from model animals that could bring mechanistic insight and preventive and therapeutic avenues.

RESULTS

Our review showed that maternal obesity had independent effects on neonatal adverse outcomes such as macrosomia, perinatal mortality and birth defects. Maternal obesity alone increased the risks for adverse neonatal outcomes, including macrosomia, perinatal mortality, induced preterm birth and birth defects. In association with excess gestational weight gain, mainly early in pregnancy, increased the risks of childhood obesity, higher fat mass and, to a smaller extent, adverse cardio-metabolic profiles. Animal models highlighted sexually dimorphic responses to maternal obesity.

CONCLUSION

Maternal obesity induced serious adverse neonatal effects and was associated with childhood obesity in their offspring. The peri-conceptional period is critical for metabolic programming, and obese women need close monitoring from conception.

CD-1 mouse fertility rapidly declines and is accompanied with early pregnancy loss under conventional housing conditions

CD-1 mice are commonly employed as a research model for defining mechanisms controlling early mammalian development and for understanding environmental impacts on mammalian fertility. CD-1 female mice were kept four to eight months under conventional animal care housing, and were fed ad libitum with normal laboratory mouse chow. Female weight, mating success, oocyte morphology, blastocyst development in vivo and in vitro, and RT-qPCR analysis of trophectoderm cell markers (Cdx2, Slc2a1, and Atp1a1 transcript abundance, and CDX2 localization) were assessed and contrasted with outcomes from four-week-old control CD-1 mice. Embryo development in vivo in four to eight-month-old mice was significantly reduced compared to four-week-old controls. Oocytes and blastocysts from four to eight-month-old CD-1 mice displayed high levels of fragmentation and degradation, significantly reduced embryo cell counts, decreased Cdx2 transcript abundance, and number of CDX2 positive cells in morulae. We have discovered that female CD-1 mice housed under conventional conditions display a rapid loss of fecundity as they age over a few months. Paradoxically, embryo loss can be avoided by placing early embryos collected from four to eight-month-old mice into culture to support development to the blastocyst stage. We conclude that oocyte quality rapidly declines in CD-1 female mice housed under conventional animal care conditions. Thus, four to eight-month-old female CD-1 mice represent a very distinct research model from that of younger mice and this older research animal model may be preferred for understanding environmental and physiological influences limiting fertility in women.

Epigenetic germline inheritance in mammals: looking to the past to understand the future

Life experiences can induce epigenetic changes in mammalian germ cells, which can influence the developmental trajectory of the offspring and impact health and disease across generations. While this concept of epigenetic germline inheritance has long been met with skepticism, evidence in support of this route of information transfer is now overwhelming, and some key mechanisms underlying germline transmission of acquired information are emerging. This review focuses specifically on sperm RNAs as causal vectors of inheritance. We examine how they might become altered in the germline, and how different classes of sperm RNAs might interact with other epimodifications in germ cells or in the zygote. We integrate the latest findings with earlier pioneering work in this field, point out major questions and challenges, and suggest how new experiments could address them.

Obesity Modulates Inflammation and Lipid Metabolism Oocyte Gene Expression: A Single-Cell Transcriptome Perspective

CONTEXT

It is hypothesized that obesity adversely affects the ovarian environment, which can disrupt oocyte maturation and embryonic development.

OBJECTIVE

This study aimed to compare oocyte gene expression profiles and follicular fluid (FF) content from overweight/obese (OW) women and normal-weight (NW) women who were undergoing fertility treatments.

DESIGN

Using single-cell transcriptomic analyses, we investigated oocyte gene expression using RNA sequencing.

PATIENTS OR OTHER PARTICIPANTS

Eleven OW women and 13 NW women undergoing fertility treatments were enrolled.

MAIN OUTCOME MEASURES

Oocyte messenger RNA profiles as well as serum and FF hormone and lipid levels were assessed.

RESULTS

OW women had significantly higher body mass index, body fat percentage, and serum homeostatic model assessment-insulin resistance index compared with NW women (P < 0.01). Serum leptin and C-reactive protein (CRP) levels as well as FF leptin, CRP, and triglyceride levels were increased (P < 0.05) in OW compared with NW women. Oocytes from OW women had increased expression of proinflammatory (CXCL2; P = 0.071) and oxidative stress-related (DUSP1; P = 0.051) genes but had decreased expression of GAS7 (fat metabolism; P = 0.065), TXNIP (oxidative stress; P = 0.055), and transcription factors ID3 (P = 0.075) and TWIST1 (P = 0.099) compared with NW women.

CONCLUSIONS

These findings provide evidence for the significant influence of body composition on oocyte transcript abundance in women undergoing hormonal induction to retrieve oocytes. They further identify the potential for maternal diet to influence oocyte gene expression. The preconception period is, therefore, an important window of opportunity to consider for lifestyle interventions.

Advanced glycation end products regulate interleukin-1β production in human placenta

Maternal obesity is a major risk factor for pregnancy complications, causing inflammatory cytokine release in the placenta, including interleukin-1β (IL-1β), IL-6, and IL-8. Pregnant women with obesity develop accelerated systemic and placental inflammation with elevated circulating advanced glycation end products (AGEs). IL-1β is a pivotal inflammatory cytokine associated with obesity and pregnancy complications, and its production is regulated by NLR family pyrin domain-containing 3 (NLRP3) inflammasomes. Here, we investigated whether AGEs are involved in the activation of NLRP3 inflammasomes using human placental tissues and placental cell line. In human placental tissue cultures, AGEs significantly increased IL-1β secretion, as well as IL-1β and NLRP3 mRNA expression. In human placental cell culture, although AGE treatment did not stimulate IL-1β secretion, AGEs significantly increased IL-1β mRNA expression and intracellular IL-1β production. After pre-incubation with AGEs, nano-silica treatment (well known as an inflammasome activator) increased IL-1β secretion in placental cells. However, after pre-incubation with lipopolysaccharide to produce pro-IL-1β, AGE treatment did not affect IL-1β secretion in placental cells. These findings suggest that AGEs stimulate pro-IL-1β production within placental cells, but do not activate inflammasomes to stimulate IL-1β secretion. Furthermore, using pharmacological inhibitors, we demonstrated that AGE-induced inflammatory cytokines are dependent on MAPK/NF-κB/AP-1 signaling and reactive oxygen species production in placental cells. In conclusion, AGEs regulate pro-IL-1β production and inflammatory responses, resulting in the activation of NLRP3 inflammasomes in human placenta. These results suggest that AGEs, as an endogenous and sterile danger signal, may contribute to chronic placental cytokine production.

Obesity and pregnancy: mechanisms of short term and long term adverse consequences for mother and child

Obesity is the most common medical condition in women of reproductive age. Obesity during pregnancy has short term and long term adverse consequences for both mother and child. Obesity causes problems with infertility, and in early gestation it causes spontaneous pregnancy loss and congenital anomalies. Metabolically, obese women have increased insulin resistance in early pregnancy, which becomes manifest clinically in late gestation as glucose intolerance and fetal overgrowth. At term, the risk of cesarean delivery and wound complications is increased. Postpartum, obese women have an increased risk of venous thromboembolism, depression, and difficulty with breast feeding. Because 50-60% of overweight or obese women gain more than recommended by Institute of Medicine gestational weight guidelines, postpartum weight retention increases future cardiometabolic risks and prepregnancy obesity in subsequent pregnancies. Neonates of obese women have increased body fat at birth, which increases the risk of childhood obesity. Although there is no unifying mechanism responsible for the adverse perinatal outcomes associated with maternal obesity, on the basis of the available data, increased prepregnancy maternal insulin resistance and accompanying hyperinsulinemia, inflammation, and oxidative stress seem to contribute to early placental and fetal dysfunction. We will review the pathophysiology underlying these data and try to shed light on the specific underlying mechanisms.

The embryonic stress response to in vitro culture: insight from genomic analysis

Recent genomic studies have shed light on the impact of in vitro culture (IVC) on embryonic homeostasis and the differential gene expression profiles associated with lower developmental competence. Consistently, the embryonic stress responses to IVC conditions correlate with transcriptomic changes in pathways related to energetic metabolism, extracellular matrix remodelling and inflammatory signalling. These changes appear to result from a developmental adaptation that enhances a Warburg-like effect known to occur naturally during blastulation. First discovered in cancer cells, the Warburg effect (increased glycolysis under aerobic conditions) is thought to result from mitochondrial dysfunction. In the case of IVC embryos, culture conditions may interfere with mitochondrial maturation and oxidative phosphorylation, forcing cells to rely on glycolysis in order to maintain energetic homeostasis. While beneficial in the short term, such adaptations may lead to epigenetic changes with potential long-term effects on implantation, foetal growth and post-natal health. We conclude that lessening the detrimental effects of IVC on mitochondrial activity would lead to significantly improved embryo quality.

Persistent influence of maternal obesity on offspring health: Mechanisms from animal models and clinical studies

The consequences of excessive maternal weight and adiposity at conception for the offspring are now well recognized. Maternal obesity increases the risk of overweight and obesity even in children born with appropriate-for-gestational age (AGA) birth weights. Studies in animal models have employed both caloric excess and manipulation of macronutrients (especially high-fat) to mimic hypercaloric intake present in obesity. Findings from these studies show transmission of susceptibility to obesity, metabolic dysfunction, alterations in glucose homeostasis, hepatic steatosis, skeletal muscle metabolism and neuroendocrine changes in the offspring. This review summarizes the essential literature in this area in both experimental and clinical domains and focuses on the translatable aspects of these experimental studies. Moreover this review highlights emerging mechanisms broadly explaining maternal obesity-associated developmental programming. The roles of early developmental alterations and placental adaptations are also reviewed. Increasing evidence also points to changes in the epigenome and other emerging mechanisms such as alterations in the microbiome that may contribute to persistent changes in the offspring. Finally, we examine potential interventions that have been employed in clinical cohorts.

Maternal Obesity in Pregnancy Developmentally Programs Adipose Tissue Inflammation in Young, Lean Male Mice Offspring

Obesity during pregnancy has a long-term effect on the health of the offspring including risk of developing the metabolic syndrome. Using a mouse model of maternal diet-induced obesity, we employed a genome-wide approach to investigate the microRNA (miRNA) and miRNA transcription profile in adipose tissue to understand mechanisms through which this occurs. Male offspring of diet-induced obese mothers, fed a control diet from weaning, showed no differences in body weight or adiposity at 8 weeks of age. However, offspring from the obese dams had up-regulated cytokine (Tnfα; P < .05) and chemokine (Ccl2 and Ccl7; P < .05) signaling in their adipose tissue. This was accompanied by reduced expression of miR-706, which we showed can directly regulate translation of the inflammatory proteins IL-33 (41% up-regulated; P < .05) and calcium/calmodulin-dependent protein kinase 1D (30% up-regulated; P < .01). We conclude that exposure to obesity during development primes an inflammatory environment in adipose tissue that is independent of offspring adiposity. Programming of adipose tissue miRNAs that regulate expression of inflammatory signaling molecules may be a contributing mechanism.

Diet-Induced Maternal Obesity Alters Insulin Signalling in Male Mice Offspring Rechallenged with a High-Fat Diet in Adulthood

Modern lifestyle has resulted in an increase in the prevalence of obesity and its comorbidities in pregnant women and the young population. It has been well established that the consumption of a high-fat diet (HFD) has many direct effects on glucose metabolism. However, it is important to assess whether maternal consumption of a HFD during critical periods of development can lead to metabolic changes in the offspring metabolism. This study evaluated the potential effects of metabolic programming on the impairment of insulin signalling in recently weaned offspring from obese dams. Additionally, we investigated if early exposure to an obesogenic environment could exacerbate the impairment of glucose metabolism in adult life in response to a HFD. Swiss female mice were fed with Standard Chow (SC) or a HFD during gestation and lactation and tissues from male offspring were analysed at d28 and d82. Offspring from obese dams had greater weight gain and higher adiposity and food intake than offspring from control dams. Furthermore, they showed impairment in insulin signalling in central and peripheral tissues, which was associated with the activation of inflammatory pathways. Adipose tissue was ultimately the most affected in adult offspring after HFD rechallenge; this may have contributed to the metabolic deregulation observed. Overall, our results suggest that diet-induced maternal obesity leads to increased susceptibility to obesity and impairment of insulin signalling in offspring in early and late life that cannot be reversed by SC consumption, but can be aggravated by HFD re-exposure.

Maternal obesity is associated with ovarian inflammation and upregulation of early growth response factor 1

Obesity impairs reproductive functions through multiple mechanisms, possibly through disruption of ovarian function. We hypothesized that increased adiposity will lead to a proinflammatory gene signature and upregulation of Egr-1 protein in ovaries from obese (OB; n = 7) compared with lean (LN; n = 10) female Sprague-Dawley rats during the peri-implantation period at 4.5 days postcoitus (dpc). Obesity was induced by overfeeding (40% excess calories for 28 days) via total enteral nutrition prior to mating. OB dams had higher body weight (P < 0.001), greater fat mass (P < 0.001), and reduced lean mass (P < 0.05) and developed metabolic dysfunction with elevated serum lipids, insulin, leptin, and CCL2 (P < 0.05) compared with LN dams. Microarray analyses identified 284 differentially expressed genes between ovaries from LN vs. OB dams (±1.3 fold, P < 0.05). RT-qPCR confirmed a decrease in expression of glucose transporters GLUT4 and GLUT9 and elevation of proinflammatory genes, including CCL2, CXCL10, CXCL11, CCR2, CXCR1, and TNFα in ovaries from OB compared with LN (P < 0.05). Protein levels of PI3K and phosphorylated Akt were significantly decreased (P < 0.05), whereas nuclear levels of Egr-1 (P < 0.05) were increased in OB compared with LN ovaries. Moreover, Egr-1 was localized to granulosa cells, with the highest expression in cumulus cells of preovulatory follicles. mRNA expression of VCAN, AURKB, and PLAT (P < 0.05) correlated with %visceral fat weight (r = 0.51, -0.77, and -0.57, respectively, P ≤ 0.05), suggesting alterations in ovarian function with obesity. In summary, maternal obesity led to an upregulation of inflammatory genes and Egr-1 expression in peri-implantation ovarian tissue and a concurrent downregulation of GLUTs and Akt and PI3K protein levels.

Assessing the fetal effects of maternal obesity via transcriptomic analysis of cord blood: a prospective case-control study

OBJECTIVE

To analyse fetal gene expression at term using umbilical cord blood, in order to provide insights into the effects of maternal obesity on human development.

DESIGN

Prospective case-control study.

SETTING

Academic tertiary care centre.

POPULATION

Eight obese (body mass index ≥30 kg/m(2)) and eight lean (body mass index <25 kg/m(2)) pregnant women undergoing prelabour caesarean delivery at term.

METHODS

Women were matched for gestational age and fetal sex. Cord blood RNA was extracted and hybridised to gene expression arrays. Differentially regulated genes were identified using paired t-tests and the Benjamini-Hochberg correction. Functional analyses were performed using Ingenuity Pathway Analysis, BioGPS and Gene Set Enrichment Analysis with a fetal-specific annotation. Z-scores ≥2.0 or P-values <0.01 were considered significant.

MAIN OUTCOME MEASURE

Functions of differentially regulated genes in fetuses of obese women.

RESULTS

A total of 701 differentially regulated genes were identified, producing an expression profile implicating neurodegeneration, decreased survival of sensory neurons, and decreased neurogenesis in the fetuses of obese women. Upstream regulators related to inflammatory signalling were significantly activated; those related to insulin receptor signalling, lipid homeostasis, regulation of axonal guidance, and cellular response to oxidative stress were significantly inhibited. Of 26 tissue-specific genes that were differentially regulated in fetuses of obese women, six mapped to the fetal brain.

CONCLUSION

Maternal obesity affects fetal gene expression at term, implicating dysregulated brain development, inflammatory and immune signalling, glucose and lipid homeostasis, and oxidative stress. This may have implications for postnatal neurodevelopment and metabolism.

Palmitic acid induces interleukin-1β secretion via NLRP3 inflammasomes and inflammatory responses through ROS production in human placental cells

Maternal obesity, a major risk factor for adverse pregnancy complications, results in inflammatory cytokine release in the placenta. Levels of free fatty acids are elevated in the plasma of obese human. These fatty acids include obesity-related palmitic acids, which is a major saturated fatty acid, that promotes inflammatory responses. Increasing evidence indicates that nucleotide-binding oligomerization domain-like receptor pyrin domain-containing 3 (NLRP3) inflammasomes mediate inflammatory responses induced by endogenous danger signals. We hypothesized that inflammatory responses associated with gestational obesity cause inflammation. To test this hypothesis, we investigated the effect of palmitic acid on the activation of NLRP3 inflammasomes and inflammatory responses in a human Sw.71 trophoblast cell line. Palmitic acid stimulated caspase-1 activation and markedly increased interleukin (IL)-1β secretion in Sw.71 cells. Treatment with a caspase-1 inhibitor diminished palmitic acid-induced IL-1β release. In addition, NLRP3 and caspase-1 genome editing using a CRISPR/Cas9 system in Sw.71 cells suppressed IL-1β secretion, which was stimulated by palmitic acid. Moreover, palmitic acid stimulated caspase-3 activation and inflammatory cytokine secretion (e.g., IL-6 and IL-8). Palmitic acid-induced cytokine secretion were dependent on caspase-3 activation. In addition, palmitic acid-induced IL-1β, IL-6, and IL-8 secretion was depended on reactive oxygen species (ROS) generation. In conclusion, palmitic acid caused activation of NLRP3 inflammasomes and inflammatory responses, inducing IL-1β, IL-6, and IL-8 secretion, which is associated with ROS generation, in human Sw.71 placental cells. We suggest that obesity-related palmitic acid induces placental inflammation, resulting in association with pregnancy complications.

Epigenetic germline inheritance of diet-induced obesity and insulin resistance

There is considerable controversy regarding epigenetic inheritance in mammalian gametes. Using in vitro fertilization to ensure exclusive inheritance via the gametes, we show that a parental high-fat diet renders offspring more susceptible to developing obesity and diabetes in a sex- and parent of origin-specific mode. The epigenetic inheritance of acquired metabolic disorders may contribute to the current obesity and diabetes pandemic.