Sex-dependent changes in lipid metabolism, PPAR pathways and microRNAs that target PPARs in the fetal liver of rats with gestational diabetes

Loss of NAT10 alleviates maternal high-fat diet-induced hepatic steatosis in male offspring of mice

OBJECTIVE

Metabolic dysfunction-associated steatotic liver disease (MASLD) is becoming an escalating health problem in pediatric populations. This study aimed to investigate the role of N-acetyltransferase 10 (NAT10) in maternal high-fat diet (HFD)-induced MASLD in offspring at early life.

METHODS

We generated male hepatocyte-specific NAT10 knockout (Nat10HKO) mice and mated them with female Nat10fl/fl mice under chow or HFD feeding. Body weight, liver histopathology, and expression of lipid metabolism-associated genes (Srebp1c, Fasn, Pparα, Cd36, Fatp2, Mttp, and Apob) were assessed in male offspring at weaning. Lipid uptake assays were performed both in vivo and in vitro. The mRNA stability assessment and RNA immunoprecipitation were performed to determine NAT10-regulated target genes.

RESULTS

NAT10 deletion in hepatocytes of male offspring alleviated perinatal lipid accumulation induced by maternal HFD, decreasing expression levels of Srebp1c, Fasn, Cd36, Fatp2, Mttp, and Apob while enhancing Pparα expression. Furthermore, Nat10HKO male mice exhibited reduced lipid uptake. In vitro, NAT10 promoted lipid uptake by enhancing the mRNA stability of CD36 and FATP2. RNA immunoprecipitation assays exhibited direct interactions between NAT10 and CD36/FATP2 mRNA.

CONCLUSIONS

NAT10 deletion in offspring hepatocytes ameliorates maternal HFD-induced hepatic steatosis through decreasing mRNA stability of CD36 and FATP2, highlighting NAT10 as a potential therapeutic target for pediatric MASLD.

Gestational supplementation of Bifidobacterium, Lactobacillus, and Streptococcus thermophilus attenuates hepatic steatosis in offspring mice through promoting fatty acid β-oxidation

Currently, Bifidobacterium, Lactobacillus, and Streptococcus thermophilus (BLS) are widely recognized as the crucially beneficial bacteria in the gut. Many preclinical and clinical studies have shown their protective effects against non-alcoholic fatty liver disease (NAFLD). However, whether gestational BLS supplementation could alleviate NAFLD in the offspring is still unknown. Kunming mice were given a high-fat diet (HFD) for 4 weeks before mating. They received BLS supplementation by gavage during pregnancy. After weaning, offspring mice were fed with a regular diet up to 5 weeks old. Gestational BLS supplementation significantly increased the abundance of Actinobacteriota, Bifidobacterium, and Faecalibaculum in the gut of dams exposed to HFD. In offspring mice exposed to maternal HFD, maternal BLS intake significantly decreased the ratio of Firmicutes to Bacteroidetes as well as the relative abundance of Prevotella and Streptococcus, but increased the relative abundance of Parabacteroides. In offspring mice, maternal BLS supplementation significantly decreased the hepatic triglyceride content and mitigated hepatic steatosis. Furthermore, maternal BLS supplementation increased the glutathione content and reduced malondialdehyde content in the liver. In addition, mRNA and protein expression levels of key rate-limiting enzymes in mitochondrial β-oxidation (CPT1α, PPARα, and PGC1α) in the livers of offspring mice were significantly increased after gestational BLS supplementation. Thus, gestational BLS supplementation may ameliorate maternal HFD-induced steatosis and oxidative stress in the livers of offspring mice by modulating fatty acid β-oxidation.

Molecular pathways in placental-fetal development and disruption

The first trimester of pregnancy ranks high in priority when minimizing harmful exposures, given the wide-ranging types of organogenesis occurring between 4- and 12-weeks' gestation. One way to quantify potential harm to the fetus in the first trimester is to measure a corollary effect on the placenta. Placental biomarkers are widely present in maternal circulation, cord blood, and placental tissue biopsied at birth or at the time of pregnancy termination. Here we evaluate ten diverse pathways involving molecules expressed in the first trimester human placenta based on their relevance to normal fetal development and to the hypothesis of placental-fetal endocrine disruption (perturbation in development that results in abnormal endocrine function in the offspring), namely: human chorionic gonadotropin (hCG), thyroid hormone regulation, peroxisome proliferator activated receptor protein gamma (PPARγ), leptin, transforming growth factor beta, epiregulin, growth differentiation factor 15, small nucleolar RNAs, serotonin, and vitamin D. Some of these are well-established as biomarkers of placental-fetal endocrine disruption, while others are not well studied and were selected based on discovery analyses of the placental transcriptome. A literature search on these biomarkers summarizes evidence of placenta-specific production and regulation of each biomarker, and their role in fetal reproductive tract, brain, and other specific domains of fetal development. In this review, we extend the theory of fetal programming to placental-fetal programming.

Early-life exposure to gestational diabetes mellitus predisposes offspring to pediatric nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has emerged as the prevailing chronic liver disease in the pediatric population due to the global obesity pandemic. Evidence shows that prenatal and postnatal exposure to maternal abnormalities leads to a higher risk of pediatric NAFLD through persistent alterations in developmental programming. Gestational diabetes mellitus (GDM) is a hyperglycemic syndrome which has become the most prevalent complication in pregnant women. An increasing number of both epidemiologic investigations and animal model studies have validated adverse and long-term outcomes in offspring following GDM exposure in utero. Similarly, GDM is considered a crucial risk factor for pediatric NAFLD. This review aimed to summarize currently published studies concerning the inductive roles of GDM in offspring NAFLD development during childhood and adolescence. Dysregulations in hepatic lipid metabolism and gut microbiota in offspring, as well as dysfunctions in the placenta are potential factors in the pathogenesis of GDM-associated pediatric NAFLD. In addition, potentially effective interventions for GDM-associated offspring NAFLD are also discussed in this review. However, most of these therapeutic approaches still require further clinical research for validation.

Virtual touch IQ elastography in the evaluation of fetal liver and placenta in pregnancies with gestational diabetes mellitus

OBJECTIVES

Elastography is considered a novel technique in the assessment of placenta parenchymal elasticity and very few data present the feasibility of elastography on human fetal tissue. This study aims to investigate the feasibility of fetal liver and placenta elastography and differences in pregnancies with GDM.

METHODS

Fifty-five women with GDM and 40 women with uncomplicated pregnancy as the control group was enrolled prospectively in this case-control study. Fetal liver VTIQ and placenta VTIQ elastography were performed between 25 and 39 weeks of pregnancy.

RESULTS

Mean placenta thickness at the level of umbilical cord insertion was significantly higher in the GDM group than in the control group (p=0.034). VTIQ elastography elasticity velocity (kPa) examinations revealed similar mean placenta and mean fetal liver stiffness in both groups. A weak to moderate correlation was observed between the mean elasticity of the placenta and the mean elasticity of the fetal liver (r=0.310; p=0.004).

CONCLUSIONS

Elastography may provide valuable information of especially on fetal tissue development and pathology. While placenta and fetal liver VTIQ elastography are feasible in pregnancy, the diagnostic value of these examinations in GDM is not certain and it seems to be that significant differences in SWE examinations that reflect structural changes in fetal tissue or placenta are more prominent in more chronic conditions such as type 1 and type 2 diabetes mellitus.

Metabolic and molecular effects of dietary extra virgin olive oil in blood and placenta of women with GDM

Gestational diabetes mellitus (GDM) increases the risks of maternal, placental, and neonatal complications. Previously, we found that a diet enriched in extra virgin olive oil (EVOO) prevents increased maternal triglyceridemia and placental proinflammatory markers in a cohort of GDM patients. The aim of this work was to evaluate maternal circulating markers of insulin resistance, placental collagen, glycogen and lipid levels, and placental levels of proteins, mRNAs, and a microRNA involved in the endocytic pathway in the same cohort of control women and women with GDM who received or did not receive a diet enriched in EVOO (36 g/day) from weeks 24 to 28 of pregnancy until term.

Results

At term, the TG/HDL cholesterol ratio, fatty acid binding protein 4 circulating levels, and maternal BMI were increased in the GDM patients, alterations prevented by the maternal diet enriched in EVOO. Although there were no changes in placental lipid levels and lipid profile, GDM placentas were thicker than controls and showed increased glycogen and collagen content, alterations prevented by the EVOO enriched diet. GDM placentas showed increases in megalin levels, in the expression of several genes involved in the endocytic pathway, and in miR-199, which targets these genes, alterations prevented by the maternal diet enriched in EVOO.

Conclusions

We identified novel beneficial effects of an EVOO-enriched diet in GDM women, a diet capable of regulating maternal insulin resistance, the structure and metabolism of the placenta, and the placental endocytic pathway, suggesting effects that may be beneficial for fetal development.

Sex differences in glycolipidic disorders after exposure to maternal hyperglycemia during early development

PURPOSE

The aim of this review was to summarize sex differences in glycolipid metabolic phenotypes of human and animal models after exposure to maternal hyperglycemia and overview the underlying mechanisms, providing a new perspective on the maternal hyperglycemia-triggered risk of glycolipidic disorders in offspring.

METHODS

A comprehensive literature search within PubMed was performed. Selected publications related to studies on offspring exposed to maternal hyperglycemia investigating the sex differences of glycolipid metabolism were reviewed.

RESULTS

Maternal hyperglycemia increases the risk of glycolipid metabolic disorders in offspring, such as obesity, glucose intolerance and diabetes. Whether with or without intervention, metabolic phenotypes have been shown to exhibit sex differences between male and female offspring in response to maternal hyperglycemia, which may be related to gonadal hormones, organic intrinsic differences, placenta, and epigenetic modifications.

CONCLUSION

Sex may play a role in the different incidences and pathogenesis of abnormal glycolipid metabolism. More studies investigating both sexes are needed to understand how and why environmental conditions in early life affect long-term health between male and female individuals.

Peroxisome proliferator-activated receptor pathways in diabetic rat decidua early after implantation: regulation by dietary polyunsaturated fatty acids

RESEARCH QUESTION

Are peroxisome proliferator-activated receptor (PPAR) pathways and moieties involved in histotrophic nutrition altered in the decidua of diabetic rats? Can diets enriched in polyunsaturated fatty acids (PUFA) administered early after implantation prevent these alterations? Can these dietary treatments improve morphological parameters in the fetus, decidua and placenta after placentation?

DESIGN

Streptozotocin-induced diabetic Albino Wistar rats were fed a standard diet or diets enriched in n3- or n6-PUFAs early after implantation. Decidual samples were collected on day 9 of pregnancy. Fetal, decidual and placental morphological parameters were evaluated on day 14 of pregnancy.

RESULTS

On gestational day 9, PPARδ levels showed no changes in the diabetic rat decidua compared with controls. In diabetic rat decidua, PPARα levels and the expression of its target genes Aco and Cpt1 had reduced. These alterations were prevented by the n6-PUFA-enriched diet. Levels of PPARγ, the expression of its target gene Fas, lipid droplet number and perilipin 2 and fatty acid binding protein 4 levels increased in the diabetic rat decidua compared with controls. Diets enriched with PUFA prevented PPARγ increase, but not the increased lipid-related PPARγ targets. On gestational day 14, fetal growth, decidual and placental weight reduced in the diabetic group, and alterations prevented by the maternal diets were enriched in PUFAs.

CONCLUSION

When diabetic rats are fed diets enriched in n3- and n6-PUFAs early after implantation, PPAR pathways, lipid-related genes and proteins, lipid droplets and glycogen content in the decidua are modulated. This influences decidual histotrophic function and later feto-placental development.

Non-coding RNAs: The link between maternal malnutrition and offspring metabolism

Early life nutrition is associated with the development and metabolism in later life, which is known as the Developmental Origin of Health and Diseases (DOHaD). Epigenetics have been proposed as an important explanation for this link between early life malnutrition and long-term diseases. Non-coding RNAs (ncRNAs) may play a role in this epigenetic programming. The expression of ncRNAs (such as long non-coding RNA H19, microRNA-122, and circular RNA-SETD2) was significantly altered in specific tissues of offspring exposed to maternal malnutrition. Changes in these downstream targets of ncRNAs lead to abnormal development and metabolism. This review aims to summarize the existing knowledge on ncRNAs linking the maternal nutrition condition and offspring metabolic diseases, such as obesity, type 2 diabetes (T2D) and non-alcoholic fatty liver disease (NAFLD).

Identification and Validation of miR-222-3p and miR-409-3p as Plasma Biomarkers in Gestational Diabetes Mellitus Sharing Validated Target Genes Involved in Metabolic Homeostasis

Gestational diabetes mellitus (GDM) causes both maternal and fetal adverse outcomes. The deregulation of microRNAs (miRNAs) in GDM suggests their involvement in GDM pathogenesis and complications. Exosomes are extracellular vesicles (EVs) of endosomal origin, released via exocytosis into the extracellular compartment. Through EVs, miRNAs are delivered in distant target cells and are able to affect gene expression. In this study, miRNA expression was analyzed to find new miRNAs that could improve GDM classification and molecular characterization. MiRNA were profiled in total plasma and EVs in GDM patients and normal glucose tolerance (NGT) women. Samples were collected at third trimester of gestation from two diabetes centers. MiRNA expression was profiled in a discovery cohort using the multiplexed NanoString nCounter Human v3 miRNA. Validation analysis was performed in a second independent cohort using RT-qPCR. A set of miRNAs resulted to be differentially expressed (DE) in total plasma and EVs in GDM. Among them, total plasma miR-222-3p and miR-409-3p were validated in the independent cohort. MiR-222-3p levels correlated with fasting plasma glucose (FPG) (p < 0.001) and birth weight (p = 0.012), whereas miR-409-3p expression correlated with FPG (p < 0.001) and inversely with gestational age (p = 0.001). The major validated target genes of the deregulated miRNAs were consistently linked to type 2 diabetes and GDM pathophysiology. MiR-222-3p and miR-409-3p are two circulating biomarkers that could improve GDM classification power and act in the context of the molecular events leading to the metabolic alterations observed in GDM.

Gestational hypercholesterolemia programs hepatic steatosis in a sex-specific manner in ApoE-deficient mice

Maternal hypercholesterolemia (MHC), a pathological condition characterized by an exaggerated rise in maternal serum cholesterol during pregnancy, may influence offspring hepatic lipid metabolism and increase the risk of nonalcoholic fatty liver disease (NAFLD). As NAFLD is characterized by a sexual dimorphic response, we assessed whether early-life exposure to excessive cholesterol influences the development of NAFLD in offspring and whether this occurs in a sex-specific manner. Female apoE-/- mice were randomly assigned to a control (CON) or a high cholesterol (CH; 0.15%) diet prior to breeding. At parturition, a cross-fostering approach was used to establish three groups: (1) normal cholesterol exposure throughout gestation and lactation (CON-CON); (2) excessive cholesterol exposure throughout gestation and lactation (CH-CH); and (3) excessive cholesterol exposure in the gestation period only (CH-CON). Adult male offspring (PND 84) exposed to excessive cholesterol during gestation only (CH-CON) demonstrated hepatic triglyceride (TG) accumulation and reduced lipogenic gene expression. However, male mice with a prolonged cholesterol exposure throughout gestation and lactation (CH-CH) had a similar, but not exacerbated hepatic response. Further, with the exception of higher serum TG in adult CH-CH females, evidence for a programming effect in female offspring was largely absent in comparison with males. These results indicate a sexual dimorphic response with respect to the effect of MHC on later life hepatic steatosis and highlight the gestation period as the most influential malprogramming window for hepatic lipid dysfunction in males.

Intrauterine Programming of Cardiovascular Diseases in Maternal Diabetes

Maternal diabetes is a prevalent pathology that increases the risk of cardiovascular diseases in the offspring, the heart being one of the main target organs affected from the fetal stage until the adult life. Metabolic, pro-oxidant, and proinflammatory alterations in the fetal heart constitute the first steps in the adverse fetal programming of cardiovascular disease in the context of maternal diabetes. This review discusses both human and experimental studies addressing putative mechanisms involved in this fetal programming of heart damage in maternal diabetes. These include cardiac epigenetic changes, alterations in cardiac carbohydrate and lipid metabolism, damaging effects caused by a pro-oxidant and proinflammatory environment, alterations in the cardiac extracellular matrix remodeling, and specific signaling pathways. Putative actions to prevent cardiovascular impairments in the offspring of mothers with diabetes are also discussed.

Significance of Sex Differences in ncRNAs Expression and Function in Pregnancy and Related Complications

In the era of personalized medicine, fetal sex-specific research is of utmost importance for comprehending the mechanisms governing pregnancy and pregnancy-related complications. In recent times, noncoding RNAs (ncRNAs) have gained increasing attention as critical players in gene regulation and disease pathogenesis, and as candidate biomarkers in human diseases as well. Different types of ncRNAs, including microRNAs (miRNAs), piwi-interacting RNAs (piRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), participate in every step of pregnancy progression, although studies taking into consideration fetal sex as a central variable are still limited. To date, most of the available data have been obtained investigating sex-specific placental miRNA expression. Several studies revealed that miRNAs regulate the (patho)-physiological processes in a sexually dimorphic manner, ensuring normal fetal development, successful pregnancy, and susceptibility to diseases. Moreover, the observation that ncRNA profiles differ according to cells, tissues, and developmental stages of pregnancy, along with the complex interactions among different types of ncRNAs in regulating gene expression, strongly indicates that more studies are needed to understand the role of sex-specific ncRNA in pregnancy and associated disorders.

Associations of prenatal exposure to phthalates and one phthalate substitute with anthropometric measures in early life: Results from the German LIFE Child cohort study

Exposure to phthalates is widespread and especially early life stages represent a critical window of exposure. In the present study, we investigated the effect of prenatal exposure to phthalates on birth outcomes and weight development in early life. In 130 mother-child pairs, we estimated the association of concentrations of 13 phthalates in spot-urine samples collected during pregnancy and birth outcomes and weight gain in the first two years of life using robust linear regression. High molecular weight phthalates were inversely associated with birth weight in girls but not in boys. Thus, prenatal exposure to phthalates may affect birth weight in a sex-specific manner.

Fetal programming by androgen excess impairs liver lipid content and PPARg expression in adult rats

It is known that prenatal hyperandrogenization induces alterations since early stages of life, contributing to the development of polycystic ovary syndrome affecting the reproductive axis and the metabolic status, thus promoting others associated disorders, such as dyslipidemia, insulin resistance, liver dysfunction, and even steatosis. In this study, we aimed to evaluate the effect of fetal programming by androgen excess on the hepatic lipid content and metabolic mediators at adult life. Pregnant rats were hyperandrogenized with daily subcutaneous injections of 1 mg of free testosterone from days 16 to 19 of pregnancy. The prenatally hyperandrogenized (PH) female offspring displayed two phenotypes: irregular ovulatory phenotype (PHiov) and anovulatory phenotype (PHanov), with different metabolic and endocrine features. We evaluated the liver lipid content and the main aspect of the balance between fatty acid (FA) synthesis and oxidation. We investigated the status of the peroxisomal proliferator-activated receptors (PPARs) alpha and gamma, which act as lipid mediators, and the adipokine chemerin, one marker of liver alterations. We found that prenatal hyperandrogenization altered the liver lipid profile with increased FAs levels in the PHanov phenotype and decreased cholesterol content in the PHiov phenotype. FA metabolism was also disturbed, including decreased mRNA and protein PPARgamma levels and impaired gene expression of the main enzymes involved in lipid metabolism. Moreover, we found low chemerin protein levels in both PH phenotypes. In conclusion, these data suggest that prenatal hyperandrogenization exerts a negative effect on the liver and alters lipid content and metabolic mediators' expression at adult age.

Intergenerational effects of the antioxidant Idebenone on the placentas of rats with gestational diabetes mellitus

Experimental models of maternal diabetes lead to the intrauterine programming of Gestational Diabetes Mellitus (GDM) in the offspring, together with an intrauterine proinflammatory environment, feto-placental metabolic alterations and fetal overgrowth. The aim of this work was to evaluate the effect of the mitochondrial antioxidant Idebenone given to F0 mild pregestational diabetic rats on the development of GDM in their F1 offspring and the intergenerational programming of a pro-oxidant/proinflammatory environment that affects the placentas of F2 fetuses. Control and mild pregestational diabetic female rats (F0) were mated with control males, and Idebenone or vehicle was administered to diabetic rats from day 1 of gestation to term. The F1 female offspring were mated with control males and maternal and fetal plasma samples were obtained for metabolic determinations at term. The F2 fetuses and placentas were weighed, and placental protein levels and peroxynitrite-induced damage (immunohistochemistry), mRNA levels (PCR), nitric oxide production (Griess reaction), and number of apoptotic cells (TUNEL) were evaluated. The F1 offspring of F0 diabetic rats (treated or not with Idebenone) developed GDM. The placentas of GDM rats showed a decrease in the mRNA levels of manganese superoxide dismutase and an increase in the production of nitric oxide, peroxynitrite-induced damage, and connective tissue growth factor levels, alterations that were prevented by the maternal Idebenone treatment in F0 rats. In conclusion, the maternal treatment with Idebenone in pregestational diabetic F0 rats ameliorates the pro-oxidant/proinflammatory environment that affects the placentas of F2 fetuses, although it does not prevent F1 rats from developing GDM.

Roles of microRNAs in carbohydrate and lipid metabolism disorders and their therapeutic potential

MicroRNAs (miRNAs) are small (∼21 nucleotides), endogenous, non-coding RNA molecules implicated in the post-transcriptional gene regulation performed through target mRNA cleavage or translational inhibition. In recent years, several investigations have demonstrated that miRNAs are involved in regulating both carbohydrate and lipid homeostasis in humans and other organisms. Moreover, it has been observed that the dysregulation of these metabolism-related miRNAs leads to the development of several metabolic disorders, such as type 2 diabetes, obesity, nonalcoholic fatty liver, insulin resistance, and hyperlipidemia. Hence, in this current review, with the aim to impulse the research arena of the micro-transcriptome implications in vital metabolic pathways as well as to highlight the remarkable potential of miRNAs as therapeutic targets for metabolic disorders in humans, we provide an overview of the regulatory roles of metabolism-associated miRNAs in humans and murine models.

Diets enriched in PUFAs at an early postimplantation stage prevent embryo resorptions and impaired mTOR signaling in the decidua from diabetic rats

Maternal diabetes increases the risk of embryo resorptions and impairs embryo development. Decidualization is crucial for embryo development and regulated by mTOR signaling. However, little is known about how maternal diabetes affects the decidua at early postimplantation stages and whether dietary treatments enriched in polyunsaturated fatty acids (PUFAs) can prevent decidual alterations. Here, we determined resorption rates, decidual mTOR pathways and markers of decidual function and remodeling in diabetic rats fed or not with diets enriched in PUFAs exclusively during the early postimplantation period. Pregestational streptozotocin-induced diabetic Albino Wistar rats and controls were fed or not with diets enriched in 6% sunflower oil or 6% chia oil (enriched in n-6 or n-3 PUFAs, respectively) on days 7, 8 and 9 of pregnancy and evaluated on day 9 of pregnancy. Maternal diabetes induced an 11-fold increase in embryo resorptions, which was prevented by both PUFAs-enriched diets despite no changes in maternal glycemia. The activity of mTOR pathway was decreased in the decidua from diabetic rats, an alteration prevented by the PUFAs-enriched diets. PUFAs-enriched diets prevented increased expression of Foxo1 (a negative regulator of mTOR) and reduced expression of miR-21 (a negative regulator of Foxo1). These diets also prevented reduced markers of decidual function (leukemia inhibitory factor and IGFBP1 expression and MMPs activity) in diabetic rat decidua. We identified the early post implantation as a crucial stage for pregnancy success, in which dietary PUFAs can protect diabetic pregnancies from embryo resorptions, decidual mTOR signaling impairments, and altered markers of decidual function and remodeling.

Peroxisome Proliferator-Activated Receptors (PPAR), fatty acids and microRNAs: Implications in women delivering low birth weight babies

Low birth weight (LBW) babies are associated with neonatal morbidity and mortality and are at increased risk for noncommunicable diseases (NCDs) in later life. However, the molecular determinants of LBW are not well understood. Placental insufficiency/dysfunction is the most frequent etiology for fetal growth restriction resulting in LBW and placental epigenetic processes are suggested to be important regulators of pregnancy outcome. Early life exposures like altered maternal nutrition may have long-lasting effects on the health of the offspring via epigenetic mechanisms like DNA methylation and microRNA (miRNA) regulation. miRNAs have been recognized as major regulators of gene expression and are known to play an important role in placental development. Angiogenesis in the placenta is known to be regulated by transcription factor peroxisome proliferator-activated receptor (PPAR) which is activated by ligands such as long-chain-polyunsaturated fatty acids (LCPUFA). In vitro studies in different cell types indicate that fatty acids can influence epigenetic mechanisms like miRNA regulation. We hypothesize that maternal fatty acid status may influence the miRNA regulation of PPAR genes in the placenta in women delivering LBW babies. This review provides an overview of miRNAs and their regulation of PPAR gene in the placenta of women delivering LBW babies.Abbreviations: AA - Arachidonic Acid; Ago2 - Argonaute2; ALA - Alpha-Linolenic Acid; ANGPTL4 - Angiopoietin-Like Protein 4; C14MC - Chromosome 14 miRNA Cluster; C19MC - Chromosome 19 miRNA Cluster; CLA - Conjugated Linoleic Acid; CSE - Cystathionine γ-Lyase; DHA - Docosahexaenoic Acid; EFA - Essential Fatty Acids; E2F3 - E2F transcription factor 3; EPA - Eicosapentaenoic Acid; FGFR1 - Fibroblast Growth Factor Receptor 1; GDM - Gestational Diabetes Mellitus; hADMSCs - Human Adipose Tissue-Derived Mesenchymal Stem Cells; hBMSCs - Human Bone Marrow Mesenchymal Stem Cells; HBV - Hepatitis B Virus; HCC - Hepatocellular Carcinoma; HCPT - Hydroxycamptothecin; HFD - High-Fat Diet; Hmads - Human Multipotent Adipose-Derived Stem; HSCS - Human Hepatic Stellate Cells; IUGR - Intrauterine Growth Restriction; LA - Linoleic Acid; LBW - Low Birth Weight; LCPUFA - Long-Chain Polyunsaturated Fatty Acids; MEK1 - Mitogen-Activated Protein Kinase 1; MiRNA - MicroRNA; mTOR - Mammalian Target of Rapamycin; NCDs - NonCommunicable Diseases; OA - Oleic Acid; PASMC - Pulmonary Artery Smooth Muscle Cell; PLAG1 - Pleiomorphic Adenoma Gene 1; PPAR - Peroxisome Proliferator-Activated Receptor; PPARα - PPAR alpha; PPARγ - PPAR gamma; PPARδ - PPAR delta; pre-miRNA - precursor miRNA; RISC - RNA-Induced Silencing Complex; ROS - Reactive Oxygen Species; SAT - Subcutaneous Adipose Tissue; WHO - World Health Organization.

Non-coding RNA crosstalk with nuclear receptors in liver disease

The dysregulation of nuclear receptors (NRs) underlies the pathogenesis of a variety of liver disorders. Non-coding RNAs (ncRNAs) are defined as RNA molecules transcribed from DNA but not translated into proteins. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are two types of ncRNAs that have been extensively studied for regulating gene expression during diverse cellular processes. NRs as therapeutic targets in liver disease have been exemplified by the successful application of their pharmacological ligands in clinics. MiRNA-based reagents or drugs are emerging as flagship products in clinical trials. Advancing our understanding of the crosstalk between NRs and ncRNAs is critical to the development of diagnostic and therapeutic strategies. This review summarizes recent findings on the reciprocal regulation between NRs and ncRNAs (mainly on miRNAs and lncRNAs) and their implication in liver pathophysiology, which might be informative to the translational medicine of targeting NRs and ncRNAs in liver disease.

An extra virgin olive oil-enriched diet improves maternal, placental, and cord blood parameters in GDM pregnancies

AIMS

To address the effect of a diet enriched in extra virgin olive oil (EVOO) on maternal metabolic parameters and placental proinflammatory markers in Gestational diabetes mellitus (GDM) patients.

METHODS

Pregnant women at 24-28 weeks of gestation were enrolled: 33 GDM patients which were randomly assigned or not to the EVOO-enriched group and 17 healthy controls. Metabolic parameters were determined. Peroxisome proliferator activated receptor (PPAR) γ and PPARα protein expression, expression of microRNA (miR)-130a and miR-518d (which respectively target these PPAR isoforms) and levels of proinflammatory markers were evaluated in term placentas. Matrix metalloproteinases (MMPs) activity was evaluated in term placentas and umbilical cord blood.

RESULTS

GDM patients that received the EVOO-enriched diet showed reduced pregnancy weight gain (GDM-EVOO:10.3 ± 0.9, GDM:14.2 ± 1.4, P = .03) and reduced triglyceridemia (GDM-EVOO:231 ± 14, GDM:292 ± 21, P = .02) compared to the non-EVOO-enriched GDM group. In GDM placentas, the EVOO-enriched diet did not regulate PPARγ protein expression or miR-130a expression, but prevented the reduced PPARα protein expression (P = .02 vs GDM) and the increased miR-518d expression (P = .009 vs GDM). Increased proinflammatory markers (interleukin-1β, tumour necrosis factor-α and nitric oxide overproduction) in GDM placentas were prevented by the EVOO-enriched diet (respectively P = .001, P = .001 and P = .01 vs GDM). MMPs overactivity was prevented in placenta and umbilical cord blood in the EVOO-enriched GDM group (MMP-9: respectively P = .01 and P = .001 vs GDM).

CONCLUSIONS

A diet enriched in EVOO in GDM patients reduced maternal triglyceridemia and weight gain and has antiinflammatory properties in placenta and umbilical cord blood, possibly mediated by the regulation of PPAR pathways.

In utero exposure to phenanthrene induces hepatic steatosis in F1 adult female mice

Environmental pollutants are thought to be a risk factor for the prevalence of hepatic steatosis. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous, and human exposure is inevitable. In the present study, phenanthrene (Phe) was used as a representative PAH to investigate the effects of in utero exposure to PAH on hepatic lipid metabolism and the toxicological mechanism involved. Pregnant mice (C57BL/6J) were orally administered Phe (0, 60, 600 and 6000 μg kg^-1 body weight) once every 3 days with 6 doses in total. F1 female mice aged 125 days showed significantly elevated hepatic lipid levels in the liver. The protein expression of hepatic peroxisome proliferator-activated receptors (PPARβ and PPARγ) and retinoid X receptors (RXRs) was upregulated; the transcription of genes related to lipogenesis, such as srebp1 (encoding sterol regulatory element binding proteins), acca (acetyl-CoA carboxylase), fasn (fatty acid synthase) and pcsk9 (proprotein convertase subtilisin/kexin type 9), showed an upregulation, while the mRNA levels of the lipolysis gene lcat (encoding lecithin cholesterol acyl transferase) were downregulated. These results could be responsible for lipid accumulation. The promoter methylation levels of pparγ were reduced and were the lowest in the 600 μg kg^-1 group, and the promoter methylation levels of lcat were significantly increased in all the Phe treatments. These changes were matched with the alterations in their mRNA levels, suggesting that prenatal Phe exposure could induce abnormal lipid metabolism in later life via epigenetic modification.

Regulating effect of Lactobacillus plantarum CQPC03 on lipid metabolism in high-fat diet-induced obesity in mice

Probiotics are regard as safety approaches for preventing and treating some chronic diseases. This study investigated the regulating effect of Lactobacillus plantarum CQPC03 (LP-CQPC03) on lipid metabolism in high-fat diet (HFD)-induced obesity in mice. The results showed that administration of LP-CQPC03 at a concentration of 1.0 × 10⁹  CFU/kg body weight inhibits HFD-induced obesity and improves lipid metabolism in the liver and serum. LP-CQPC03 intervention attenuated obesity-induced hepatic tissue damage, led decreases in hepatic triglyceride (42.02 mmol/gprot), total cholesterol (3.85 mmol/gprot), and LDL-C (1.03 mmol/gprot), and an increase in HDL-C (1.07 mmol/gprot). The same tendencies were observed in serum of HFD-fed mice. LP-CQPC03 intervention led a decrease in serum levels of aspartic transaminase, alanine transaminase, and alkaline phosphatase. LP-CQPC03 alleviated inflammation by increasing the level of interleukin (IL)-4 and IL-10, and decreasing the levels of pro-inflammatory factors, including IL-6, IL-1β, tumor necrosis factor-α, and interferon-γ. LP-CQPC03 also increased activities of SOD and GSH-Px in liver significantly and dropped the hepatic malondialdehyde (MDA) level from 3.39 nmol/gprot to 1.90 nmol/gprot. RT-qPCR results showed that the lipid metabolism-improving effect of LP-CQPC03 was performed by upregulating the expression of carnitine palmitoyltransferase 1, lipoprotein lipase, catalase, and superoxide dismutase 1. This study indicates that L. plantarum CQPC03 might be a potential probiotic that can help mitigate the adverse effects of excessive lipids on the liver, and prevent or alleviate high-energy intake-related obesity. PRACTICAL APPLICATIONS: Intaking high-energy foods is a potential risk of lipid metabolic disorder. Therefore, it is necessary to seek an effective and safe approach for preventing the obesity-related disease. This study found that LP-CQPC03 limited the rate of increase in body weight of mice fed on HFD, maintained normal hepatic tissue morphology, and exhibited a strong regulating effect on lipid metabolism. And the threshold concentration of LP-CQPC03 for the lipid-lowering effect was 1.0 × 10⁹  CFU/kg body weight. Therefore, LP-CQPC03 is a potential probiotic for preventing or alleviating high-energy intake-related obesity.

The offspring from rats fed a fatty diet display impairments in the activation of liver peroxisome proliferator activated receptor alpha and features of fatty liver disease

Maternal obesity programs liver derangements similar to those of NAFLD. Our main goal was to evaluate whether these liver anomalies were related to aberrant PPARα function. Obesity was induced in female Albino-Wistar rats by a fatty diet (FD rats). Several parameters related to NAFLD were evaluated in both plasma and livers from fetuses of 21 days of gestation and 140-day-old offspring. FD fetuses and offspring developed increased levels of AST and ALT, signs of inflammation and oxidative and nitrative stress-related damage. FD offspring showed dysregulation of Plin2, CD36, Cyp4A, Aco, Cpt-1, Hadha and Acaa2 mRNA levels, genes involved in lipid metabolism and no catabolic effect of the PPARα agonist clofibrate. These results suggest that the FD offspring is prone to develop fatty liver, a susceptibility that can be linked to PPARα dysfunction, and that this could in turn be related to the liver impairments programmed by maternal obesity.

Proinflammation in maternal and fetal livers and circulating miR-122 dysregulation in a GDM rat model induced by intrauterine programming

In gestational diabetes mellitus (GDM) pregnancies, a compromised fetal liver may impact offspring's metabolic health. Here, we aimed to address prooxidant, proinflammatory and profibrotic markers in the livers from GDM rats and their fetuses, and to analyze the expression of miR-122 (a relevant microRNA in liver pathophysiology) in fetal and maternal plasma of GDM rats, as well as in the fetal livers of neonatal streptozotocin-induced (nSTZ) diabetic rats, the rats that generate GDM through intrauterine programming. GDM and nSTZ rats were evaluated on day 21 of pregnancy. We found increased nitric oxide production and lipoperoxidation in the livers from GDM rats and their fetuses compared to controls. Livers from GDM fetuses also showed increased levels of connective tissue growth factor and matrix metalloproteinase-2. The expression of miRNA-122 was downregulated in the plasma from GDM rats and their male fetuses, as well as in the livers from male fetuses of nSTZ diabetic rats. miR-122 levels were regulated both in vitro through PPARγ activation and in vivo through a maternal diet enriched in PPAR ligands. Our findings revealed a prooxidant/proinflammatory environment in the livers from GDM rats and their fetuses and a dysregulation of miR-122, likely relevant in the programming of offspring's diseases.

Non-Coding RNA: Role in Gestational Diabetes Pathophysiology and Complications

Gestational Diabetes Mellitus (GDM) is defined as glucose intolerance that develops in the second or third trimester of pregnancy. GDM can lead to short-term and long-term complications both in the mother and in the offspring. Diagnosing and treating this condition is therefore of great importance to avoid poor pregnancy outcomes. There is increasing interest in finding new markers with potential diagnostic, prognostic and therapeutic utility in GDM. Non-coding RNAs (ncRNAs), including microRNAs, long non-coding RNAs and circular RNAs, are critically involved in metabolic processes and their dysregulated expression has been reported in several pathological contexts. The aberrant expression of several circulating or placenta-related ncRNAs has been linked to insulin resistance and β-cell dysfunction, the key pathophysiological features of GDM. Furthermore, significant associations between altered ncRNA profiles and GDM-related complications, such as macrosomia or trophoblast dysfunction, have been observed. Remarkably, the deregulation of ncRNAs, which might be linked to a detrimental intrauterine environment, can lead to changes in the expression of target genes in the offspring, possibly contributing to the development of long-term GDM-related complications, such as metabolic and cardiovascular diseases. In this review, all the recent findings on ncRNAs and GDM are summarized, particularly focusing on the molecular aspects and the pathophysiological implications of this complex relationship.

Maternal diets enriched in olive oil regulate lipid metabolism and levels of PPARs and their coactivators in the fetal liver in a rat model of gestational diabetes mellitus

In a rat model of gestational diabetes mellitus (GDM) programmed in the offspring of neonatal streptozotocin-induced (nSTZ) diabetic rats, lipids are accumulated in the fetal liver in a sex-dependent way. Here, we evaluated whether maternal diets enriched in olive oil in rats that will develop GDM ameliorate lipid metabolic impairments in the fetal livers. Pregnant offspring of control and nSTZ diabetic rats (F0) were fed a 6% olive oil-supplemented diet throughout the F1 gestation. We evaluated maternal metabolic parameters as well as lipid content, expression of lipid metabolizing enzymes and protein expression of PLIN2, PPARs and PPAR coactivators in the fetal livers. The offspring of nSTZ diabetic rats developed GDM regardless of the maternal treatment. Hypertriglyceridemia in GDM rats was prevented by the olive oil-enriched maternal treatment. In the livers of male fetuses of GDM rats, the maternal olive oil-supplemented diet prevented lipid overaccumulation and prevented the increase in PPARγ and PPARδ levels. In the livers of female fetuses of GDM rats, the maternal olive oil supplementation prevented the increase in PPARδ levels and the reduction in PGC1α levels, but did not prevent the reduced lipid content. Control and GDM rats showed a reduction of lipid metabolic enzymes in the fetal livers, which was associated with reduced levels of the PPAR coactivators PGC-1α and SRC-1 in males and of SRC-1 in females. These results suggest powerful effects of a maternal olive oil-supplemented diet in the fetal liver, possibly providing benefits in the fetuses and offspring from GDM rats.

Dichotomy of bisphenol A-induced expression of peroxisome proliferator-activated receptors in hepatic and testicular tissues in mice

Environmental and dietary exposure to bisphenol A (BPA) and its toxicological consequences are extensively reported. BPA has multiple cellular targets. One of the mechanisms of action of BPA involves interaction with and activation of nuclear receptors (NRs) including peroxisome proliferator activated-receptors (PPARs). PPARs regulate genes involved in adipogenesis, and metabolism of glucose, lipid and cholesterol. Study of tissue and dose specific PPAR expression may decipher the toxicity outcome of BPA exposure. We studied expression of three forms of PPARs in mouse liver and testes exposed to BPA for 14 days. mRNA and protein expression of all forms of PPAR increased linearly (monotonic) with the dose in the liver while non-monotonic but dose specific effects were observed in the testes showing a differential pattern of expression. However, histopathological study showed a dose-dependent pattern of changes in liver as well as testes demonstrating a monotonic effect. These findings imply that other PPAR-independent mechanisms may play a role in BPA-induced pathological changes. The present study warrants exploration of the role of PPARs in BPA-induced effects on male reproductive functions and offers an insight into the peculiar response of BPA at low subchronic levels which may be helpful in designing appropriate risk assessment framework.

Altered FOXO1 activation in the programming of cardiovascular alterations by maternal diabetes

Maternal diabetes programs cardiovascular alterations in the adult offspring but the mechanisms involved remain unclarified. Here, we addresed whether maternal diabetes programs cardiac alterations related to extracellular matrix remodeling in the adult offspring, as well as the role of forkhead box transcription factor 1 (FOXO1) in the induction of these alterations. The heart from adult offspring from control and streptozotocin-induced diabetic rats was evaluated. Increased glycemia, triglyceridemia and insulinemia and markers of cardiomyopathy were found in the offspring from diabetic rats. In the heart, an increase in active FOXO1 and mRNA levels of its target genes, Mmp-2 and Ctgf, genes related to an altered extracellular matrix remodeling, together with an increase in collagen deposition and a decrease in the connexin43 levels, were found in the offspring from diabetic rats. Altogether, these results suggest an important role of FOXO1 activation in the cardiac alterations induced by intrauterine programming in maternal diabetes.

A New Insight into the Roles of MiRNAs in Metabolic Syndrome

Metabolic syndrome (MetS), which includes several clinical components such as abdominal obesity, insulin resistance (IR), dyslipidemia, microalbuminuria, hypertension, proinflammatory state, and oxidative stress (OS), has become a global epidemic health issue contributing to a high risk of type 2 diabetes mellitus (T2DM). In recent years, microRNAs (miRNAs), used as noninvasive biomarkers for diagnosis and therapy, have aroused global interest in complex processes in health and diseases, including MetS and its components. MiRNAs can exist stably in serum, liver, skeletal muscle (SM), heart muscle, adipose tissue (AT), and βcells, because of their ability to escape the digestion of RNase. Here we first present an overall review on recent findings of the relationship between miRNAs and several main components of MetS, such as IR, obesity, diabetes, lipid metabolism, hypertension, hyperuricemia, and stress, to illustrate the targeting proteins or relevant pathways that are involved in the progress of MetS and also help us find promising novel diagnostic and therapeutic strategies.

Association of Early Life Exposure to Phthalates With Obesity and Cardiometabolic Traits in Childhood: Sex Specific Associations

Few studies have investigated longitudinal associations between early life phthalate exposure and subsequent obesity and cardiovascular risks in children with inconsistent results. We aimed to evaluate the associations between phthalate exposure during gestation and childhood with offspring obesity and cardiometabolic risk factors in 500 mother-child pairs from the Rhea pregnancy cohort in Crete, Greece. Seven phthalate metabolites [monoethyl phthalate (MEP), mono-n-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP), monobenzyl phthalate (MBzP), mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP)] were quantified in spot urine samples collected from mothers (1st trimester) and their children at 4 years of age. We calculated the molar sum of DEHP metabolites (MEHP, MEHHP, MEOHP). We measured child weight, height, waist circumference, skinfold thicknesses, blood pressure (BP), and lipids at 4 and 6 years and leptin, adiponectin, and C-reactive protein at 4 years. We used generalized estimating equations to examine associations at each age and tested for interaction by sex. Child exposure to phthalate metabolites was associated with lower BMI z-scores in boys and higher BMI z-scores in girls. Each 10-fold increase in ΣDEHP was associated with a change in waist circumference of −2.6 cm (95% CI: −4.72, −0.48) in boys vs. 2.14 cm (95% CI: −0.14, 4.43) in girls (p-sex interaction = 0.003) and a change in waist-to-height ratio of −0.01 (95% CI: −0.03, 0.01) in boys vs. 0.02 (95% CI: 0.01, 0.04) in girls (p-sex interaction = 0.006). Phthalate metabolite concentrations at age 4 were negatively associated with systolic and diastolic blood pressure. MEP was associated with lower systolic BP z-scores (adj. β = −0.22; 95% CI: −0.36, −0.08) at 4 years. MnBP and MBzP were associated with lower diastolic BP z-scores (adj. β = −0.13; 95%CI: −0.23, −0.04, and adj. β = −0.11; 95% CI: −0.21, −0.01, respectively). A 10-fold increase in MiBP was associated with 4.4% higher total cholesterol levels (95% CI: 0.2, 8.7). Prenatal phthalate exposure was not consistently associated with child adiposity and cardiometabolic measures. Our findings suggest that early life phthalate exposure may affect child growth and adiposity in a sex-specific manner and depends on the timing of exposure.

Gestational diabetes alters microRNA signatures in human feto-placental endothelial cells depending on fetal sex

MicroRNAs (miRNAs), small non-coding RNAs, have emerged as important, epigenetic regulators of endothelial function. Metabolic disturbances such as diabetes alter miRNA expression. In adults, the miRNA transcriptome as well as endothelial function differ between the sexes. Here, we hypothesized that metabolic disturbances associated with gestational diabetes (GDM) alter miRNA signatures in feto-placental endothelial cells (fpEC), dependent on fetal sex. We isolated human primary fpEC after normal and GDM-complicated pregnancies with male and female neonates and screened for differential miRNA expression using next-generation miRNA sequencing. To test for miRNAs commonly regulated in fpEC of female and male progeny, data were stratified for fetal sex and maternal body mass index (BMI). Analyses were also performed separately for female and male fpEC, again accounting for maternal BMI as covariate. Potential biological pathways regulated by the altered set of miRNAs were determined using mirPath software. Maternal GDM altered 26 miRNA signatures when male and female fpEC were analyzed together. Separate analysis of male versus female fpEC revealed 22 GDM affected miRNAs in the females and only 4 in the males, without overlap. Biological functions potentially modulated by the affected miRNAs related to ‘Protein Processing in Endoplasmic Reticulum’ and ‘Proteoglycans in Cancer’. Maternal GDM alters miRNA signatures in fpEC, and biological functions affected by these miRNAs relate to well-known adverse functional consequences of diabetes on endothelium. GDM effects were highly dependent on fetal sex with miRNA signatures in female fpEC being more susceptible to metabolic derangements of GDM than miRNAs in male fpEC.

Diet Enriched with Olive Oil Attenuates Placental Dysfunction in Rats with Gestational Diabetes Induced by Intrauterine Programming

SCOPE

Offspring from rats with mild diabetes develop gestational diabetes mellitus (GDM). We tested the hypothesis that an olive oil-supplemented diet attenuates placental oxidative stress/inflammation, activation of mTOR signaling, and inhibition of peroxisome proliferator-activated receptor γ (PPARγ) and fetal overgrowth in GDM offspring from mild diabetic rats.

METHODS AND RESULTS

Female offspring from rats with mild diabetes (group that developed GDM) and controls were fed with either a standard diet or a 6% olive oil-supplemented diet during pregnancy. On day 21 of pregnancy, plasma glucose levels in mothers and fetuses were increased in the GDM group independently of the diet. Fetal overgrowth and activation of placental mTOR signaling were partially prevented in the olive oil-treated GDM group. Placental PPARγ protein expression was decreased in GDM rats, independently of the diet. However, increases in placental lipoperoxidation, connective tissue growth factor, and matrix metalloproteinase 2 levels were prevented by the olive oil-enriched diet.

CONCLUSION

Diets enriched with olive oil attenuate placental dysfunction and fetal overgrowth in rats with GDM induced by intrauterine programming.