Regulation of energy metabolism pathways by estrogens and estrogenic chemicals and potential implications in obesity associated with increased exposure to endocrine disruptors

Di (2-ethyl hexyl) phthalate and its metabolite-induced metabolic syndrome: a review of molecular mechanisms

OBJECTIVES

Metabolic disorders, as multifactorial disorders, are induced by genetic susceptibility and exposure to environmental chemicals. Di (2-ethyl hexyl) phthalate (DEHP), a ubiquitous plasticizer, is well known as an endocrine-disrupting chemical in living organisms. In recent decades, researchers have focused on the potential of DEHP and its main metabolite (Mono (2-ethylhexyl) phthalate) (MEHP) to induce metabolic disorders. In the present review, we aimed to summarize studies regarding DEHP and MEHP-induced Metabolic syndrome (MetS) as well as address the involved mechanisms.

METHODS

A search has been carried out in Google Scholar, PubMed, Scopus, and Web of Science databases using appropriate keywords including 'Metabolic syndrome' or 'Metabolic disorder' or 'Obesity' or 'Hyperglycemia' or 'Hyperlipidemia' or 'Hypertension' or 'Non-alcoholic fatty liver disease' and 'DEHP' or 'Di (2-ethyl hexyl) phthalate' or 'Bis(2-ethylhexyl) phthalate' or 'MEHP' or 'Mono (2-ethylhexyl) phthalate'. Studies were chosen based on inclusion and exclusion criteria. Inclusion criteria are in vitro, in vivo, epidemiological studies, and English-written studies. Exclusion criteria are lack of access to the full text of studies, editorial articles, review articles, and conference articles.

RESULTS

Animal studies indicate that DEHP and MEHP disrupt insulin hemostasis, increase glucose content, and induce hyperlipidemia and hypertension as well as obesity, which could lead to type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). DEHP and its metabolite induce such effects directly through influence on nuclear receptors such as peroxisome proliferator-activated receptors (PPARs) or indirectly through reactive oxygen species (ROS) production. Both events led to the disruption of several molecular signaling pathways and subsequently metabolic syndrome (MetS). Furthermore, epidemiological studies showed that there was a correlation between DEHP metabolites levels and obesity, hyperglycemia, and hypertension.

CONCLUSIONS

According to studies, DEHP and its main metabolite have the potential to induce MetS by involving various molecular mechanisms. Epidemiological studies concerning the association of DEHP and MetS in humans are not sufficient. Therefore, more studies are needed in this regard.

Research status of anti-obesogenic functional foods: mechanism of endocrine-disrupting chemicals and glucocorticoid receptor pathway

Obesity due to excessive fat accumulation, affects health and quality of life and increases the risk of diseases such as type 2 diabetes and cardiovascular conditions. Traditional causes, such as calorie excess and sedentary behavior, do not fully explain the obesity epidemic, leading to the hypothesis that endocrine-disrupting chemicals or obesogens contribute to obesity. The obesogenic mechanisms of representative obesogenic substances, such as bisphenols, have been discussed, mainly focusing on their interactions with estrogen receptors. Based on several studies showing that obesogens induce obesity by mimicking glucocorticoids, this review focused on the role of the glucocorticoid receptor pathway. In addition, the anti-obesogenic bioactive substances that have been studied to this date along with their inhibitory mechanisms were discussed.

Global metabolomic alterations associated with endocrine-disrupting chemicals among pregnant individuals and newborns

BACKGROUND

Gestational exposure to non-persistent endocrine-disrupting chemicals (EDCs) may be associated with adverse pregnancy outcomes. While many EDCs affect the endocrine system, their effects on endocrine-related metabolic pathways remain unclear. This study aims to explore the global metabolome changes associated with EDC biomarkers at delivery.

METHODS

This study included 75 pregnant individuals who delivered at the University of Cincinnati Hospital from 2014 to 2017. We measured maternal urinary biomarkers of paraben/phenol (12), phthalate (13), and phthalate replacements (4) from the samples collected during the delivery visit. Global serum metabolome profiles were analyzed from maternal blood (n = 72) and newborn (n = 63) cord blood samples collected at delivery. Fifteen of the 29 urinary biomarkers were excluded due to low detection frequency or potential exposures during hospital stay. We assessed metabolome-wide associations between 14 maternal urinary biomarkers and maternal/newborn metabolome profiles. Additionally, performed enrichment analysis to identify potential alterations in metabolic pathways.

RESULTS

We observed metabolome-wide associations between maternal urinary concentrations of phthalate metabolites (mono-isobutyl phthalate), phthalate replacements (mono-2-ethyl-5-carboxypentyl terephthalate, mono-2-ethyl-5-hydroxyhexyl terephthalate) and phenols (bisphenol-A, bisphenol-S) and maternal serum metabolome, using q-value < 0.2 as a threshold. Additionally, associations of phthalate metabolites (mono-n-butyl phthalate, monobenzyl phthalate) and phenols (2,5-dichlorophenol, BPA) with the newborn metabolome were noted. Enrichment analyses revealed associations (p-gamma < 0.05) with amino acid, carbohydrate, lipid, glycan, vitamin, and other cofactor metabolism pathways.

CONCLUSION

Maternal paraben, phenol, phthalate, and phthalate replacement biomarker concentrations at delivery were associated with maternal and newborn serum global metabolome.

Molecular Mechanisms of Phthalate-Induced Hepatic Injury and Amelioration by Plant-Based Principles

Phthalates are the emerging environmental toxicants derived from phthalic acid and its constituents, which are moderately present in plastics and many personal care products. Phthalate exposure occurs through various environmental factors, including air, water, and soil, with absorption facilitated via ingestion, inhalation, and dermal contact. Upon exposure, phthalates become bioavailable within the biological systems and undergo biotransformation and detoxification processes in the liver. The physicochemical properties of phthalates indicate their lipophilicity, environmental persistence, and bioaccumulation potential, influencing their absorption, distribution, and hepatic biotransformation. The prolonged exposure to phthalates adversely influences the biological redox system by altering the levels of the enzymatic and non-enzymatic antioxidants, molecular signaling pathways, and causing hepatic pathogenesis. The strategies to combat phthalate-induced toxicity include avoiding exposure to these compounds and using plant-based bioactive molecules such as polyphenols, which possess therapeutic potential as antioxidants, suppress inflammatory cascades, prevent oxidative damage, and stabilize cellular integrity. This review presents a comprehensive and updated account of the chemical, biochemical, immunological, and toxicological properties of phthalates, along with novel plant-based therapeutic strategies to mitigate the phthalate-induced adverse effects on living systems.

Obesity and the development of Parkinson's disease within the Framingham Heart study cohort

Objective

To determine the role of obesity in the development of Parkinson's disease (PD).

Background

Obesity has been reported to be both a risk factor for PD, as well as potentially protective. The Framingham Heart Study (FHS) is a multigenerational longitudinal cohort study that was started in 1948, which is well-known for its cardiovascular health studies. In this study, we utilized the extensive cardiovascular and neurological data to determine if obesity contributes to the risk of the development of PD.

Methods

Participants in the FHS Original and Offspring cohorts were included in this study. Controls were selected based on sex and age at baseline examination, 1:10. Cox proportional hazard regression models were used, adjusting for age and sex. PD case status was determined utilizing prior medical and neurological examination data, Framingham Heart Study examinations, and self-report data by a panel of movement disorders neurologists using the UK Brain Bank Criteria (UKBB) and other supporting clinical details after being flagged for review by FHS neurologists. We used p < 0.05 for significance.

Results

Accounting for missing covariate data, this study included 117 participants with PD, with 1170 controls. We found that higher BMI was associated with lower PD risk, with participants with BMI 25 kg/m2 to 30 kg/m2 having HR of 0.66 (CI 0.44-0.98; p = 0.04) and BMI >= 30 kg/m2 having HR 0.47 (CI 0.27-0.84; p = 0.01). When the overweight and obese BMI groups were combined, we noted a more robust association, with combined HR of 0.67 (0.41-0.86; p = 0.01).

Conclusions

Obesity during mid-life potentially reduces the risk of developing PD; however, additional studies are needed to further explore this association.

Estrogen receptors in mitochondrial metabolism: age-related changes and implications for pregnancy complications

Estrogen hormones are primarily associated with their role as female sex hormones responsible for primary and secondary sexual development. Estrogen receptors are known to undergo age-dependent decreases due to age-related changes in hormone production. In the mitochondria, estrogen functions by reducing the production of reactive oxygen species in the electron transport chain, inhibiting apoptosis, and regulating mitochondrial DNA content. Moreover, estrogen receptors may be the key components in maintaining mitochondrial membrane potential and structure. Although estrogen plays a crucial role in the development of pregnancy, our understanding of how estrogen receptors change with aging during pregnancy remains limited. During pregnancy, estrogen levels are significantly elevated, with a corresponding upregulation of estrogen receptors, which play various roles in pregnancy. However, the exact role of estrogen receptors in pregnancy complications remains to be further investigated. The paper reviews the role of estrogen receptors in the regulation of mitochondrial metabolism and in pregnancy complications, with a special focus on the effect of age-related changes on estrogen levels and estrogen receptors function. We also address how estrogen maintains mitochondrial function, including reducing the production of reactive oxygen species in the electron transport chain, inhibiting apoptosis, regulating mitochondrial DNA content, and maintaining mitochondrial membrane potential and structure. However, the effects of estrogen on mitochondria-endoplasmic reticulum contacts have not been well studied. Based on these emergent roles in mitochondria, the differential roles of estrogen receptors in pregnancy complications are of great relevance. The paper emphasizes the association between maternal health and estrogen receptors and indicates the need for future research to elucidate the interdependence of estrogen receptor-regulated maternal health with mitochondrial function and their relationship with the gut microbiome. Overall, we summarize the important role of estrogen receptors during pregnancy and highlight the need for further research to better understand the role of estrogen receptors in aging and pregnancy complications. This not only helps to reveal the mechanism underlying the role of estrogen in maternal health but also has potential clinical implications for the development of new therapies targeting age-related diseases and pregnancy complications.

Bisphenol A (BPA) toxicity assessment and insights into current remediation strategies

Bisphenol A (BPA) raises concerns among the scientific community as it is one of the most widely used compounds in industrial processes and a component of polycarbonate plastics and epoxy resins. In this review, we discuss the mechanism of BPA toxicity in food-grade plastics. Owing to its proliferation in the aqueous environment, we delved into the performance of various biological, physical, and chemical techniques for its remediation. Detailed mechanistic insights into these removal processes are provided. The toxic effects of BPA unravel as changes at the cellular level in the brain, which can result in learning difficulties, increased aggressiveness, hyperactivity, endocrine disorders, reduced fertility, and increased risk of dependence on illicit substances. Bacterial decomposition of BPA leads to new intermediates and products with lower toxicity. Processes such as membrane filtration, adsorption, coagulation, ozonation, and photocatalysis have also been shown to be efficient in aqueous-phase degradation. The breakdown mechanism of these processes is also discussed. The review demonstrates that high removal efficiency is usually achieved at the expense of high throughput. For the scalable application of BPA degradation technologies, removal efficiency needs to remain high at high throughput. We propose the need for process intensification using an integrated combination of these processes, which can solve multiple associated performance challenges.

Transcriptional profiling of lung macrophages following ozone exposure in mice identifies signaling pathways regulating immunometabolic activation

Macrophages play a key role in ozone-induced lung injury by regulating both the initiation and resolution of inflammation. These distinct activities are mediated by pro-inflammatory and anti-inflammatory/proresolution macrophages which sequentially accumulate in injured tissues. Macrophage activation is dependent, in part, on intracellular metabolism. Herein, we used RNA-sequencing (seq) to identify signaling pathways regulating macrophage immunometabolic activity following exposure of mice to ozone (0.8 ppm, 3 h) or air control. Analysis of lung macrophages using an Agilent Seahorse showed that inhalation of ozone increased macrophage glycolytic activity and oxidative phosphorylation at 24 and 72 h post-exposure. An increase in the percentage of macrophages in S phase of the cell cycle was observed 24 h post ozone. RNA-seq revealed significant enrichment of pathways involved in innate immune signaling and cytokine production among differentially expressed genes at both 24 and 72 h after ozone, whereas pathways involved in cell cycle regulation were upregulated at 24 h and intracellular metabolism at 72 h. An interaction network analysis identified tumor suppressor 53 (TP53), E2F family of transcription factors (E2Fs), cyclin-dependent kinase inhibitor 1A (CDKN1a/p21), and cyclin D1 (CCND1) as upstream regulators of cell cycle pathways at 24 h and TP53, nuclear receptor subfamily 4 group a member 1 (NR4A1/Nur77), and estrogen receptor alpha (ESR1/ERα) as central upstream regulators of mitochondrial respiration pathways at 72 h. To assess whether ERα regulates metabolic activity, we used ERα-/- mice. In both air and ozone-exposed mice, loss of ERα resulted in increases in glycolytic capacity and glycolytic reserve in lung macrophages with no effect on mitochondrial oxidative phosphorylation. Taken together, these results highlight the complex interaction between cell cycle, intracellular metabolism, and macrophage activation which may be important in the initiation and resolution of inflammation following ozone exposure.

Estrogen promotes fetal skeletal muscle mitochondrial distribution and ATP synthase activity important for insulin sensitivity in offspring

PURPOSE

We previously showed that offspring delivered to baboons in which levels of estradiol (E2) were suppressed during the second half of gestation exhibit insulin resistance. Mitochondria are essential for the production of ATP as the main source of energy for intracellular metabolic pathways, and skeletal muscle of type 2 diabetics exhibit mitochondrial abnormalities. Mitochondria express estrogen receptor β and E2 enhances mitochondrial function in adults. Therefore, the current study ascertained whether exposure of the fetus to E2 is essential for mitochondrial development.

METHODS

Levels of ATP synthase and citrate synthase and the morphology of mitochondria were determined in fetal skeletal muscle obtained near term from baboons untreated or treated daily with the aromatase inhibitor letrozole or letrozole plus E2.

RESULTS

Specific activity and amount of ATP synthase were 2-fold lower (P < 0.05) in mitochondria from skeletal muscle of E2 suppressed letrozole-treated fetuses and restored to normal by treatment with letrozole plus E2. Immunocytochemistry showed that in contrast to the punctate formation of mitochondria in myocytes of untreated and letrozole plus E2 treated animals, mitochondria appeared to be diffuse in myocytes of estrogen-suppressed fetuses. However, citrate synthase activity and levels of proteins that control mitochondrial fission/fusion were similar in estrogen replete and suppressed animals.

CONCLUSION

We suggest that estrogen is essential for fetal skeletal muscle mitochondrial development and thus glucose homeostasis in adulthood.

White-to-Beige and Back: Adipocyte Conversion and Transcriptional Reprogramming

Obesity has become a pandemic, as currently more than half a billion people worldwide are obese. The etiology of obesity is multifactorial, and combines a contribution of hereditary and behavioral factors, such as nutritional inadequacy, along with the influences of environment and reduced physical activity. Two types of adipose tissue widely known are white and brown. While white adipose tissue functions predominantly as a key energy storage, brown adipose tissue has a greater mass of mitochondria and expresses the uncoupling protein 1 (UCP1) gene, which allows thermogenesis and rapid catabolism. Even though white and brown adipocytes are of different origin, activation of the brown adipocyte differentiation program in white adipose tissue cells forces them to transdifferentiate into "beige" adipocytes, characterized by thermogenesis and intensive lipolysis. Nowadays, researchers in the field of small molecule medicinal chemistry and gene therapy are making efforts to develop new drugs that effectively overcome insulin resistance and counteract obesity. Here, we discuss various aspects of white-to-beige conversion, adipose tissue catabolic re-activation, and non-shivering thermogenesis.

Analysis of arsenic-modulated expression of hypothalamic estrogen receptor, thyroid receptor, and peroxisome proliferator-activated receptor gamma mRNA and simultaneous mitochondrial morphology and respiration rates in the mouse

Arsenic has been identified as an environmental toxicant acting through various mechanisms, including the disruption of endocrine pathways. The present study assessed the ability of a single intraperitoneal injection of arsenic, to modify the mRNA expression levels of estrogen- and thyroid hormone receptors (ERα,β; TRα,β) and peroxisome proliferator-activated receptor gamma (PPARγ) in hypothalamic tissue homogenates of prepubertal mice in vivo. Mitochondrial respiration (MRR) was also measured, and the corresponding mitochondrial ultrastructure was analyzed. Results show that ERα,β, and TRα expression was significantly increased by arsenic, in all concentrations examined. In contrast, TRβ and PPARγ remained unaffected after arsenic injection. Arsenic-induced dose-dependent changes in state 4 mitochondrial respiration (St4). Mitochondrial morphology was affected by arsenic in that the 5 mg dose increased the size but decreased the number of mitochondria in agouti-related protein- (AgRP), while increasing the size without affecting the number of mitochondria in pro-opiomelanocortin (POMC) neurons. Arsenic also increased the size of the mitochondrial matrix per host mitochondrion. Complex analysis of dose-dependent response patterns between receptor mRNA, mitochondrial morphology, and mitochondrial respiration in the neuroendocrine hypothalamus suggests that instant arsenic effects on receptor mRNAs may not be directly reflected in St3-4 values, however, mitochondrial dynamics is affected, which predicts more pronounced effects in hypothalamus-regulated homeostatic processes after long-term arsenic exposure.

Risk factor analysis and risk prediction study of obesity in steelworkers: model development based on an occupational health examination cohort dataset

BACKGROUND

Obesity is increasingly recognized as a grave public health concern globally. It is associated with prevalent diseases including coronary heart disease, fatty liver, type 2 diabetes, and dyslipidemia. Prior research has identified demographic, socioeconomic, lifestyle, and genetic factors as contributors to obesity. Nevertheless, the influence of occupational risk factors on obesity among workers remains under-explored. Investigating risk factors specific to steelworkers is crucial for early detection, prediction, and effective intervention, thereby safeguarding their health.

METHODS

This research utilized a cohort study examining health impacts on workers in an iron and steel company in Hebei Province, China. The study involved 5469 participants. By univariate analysis, multifactor analysis, and review of relevant literature, predictor variables were found. Three predictive models-XG Boost, Support Vector Machine (SVM), and Random Forest (RF)-were employed.

RESULTS

Univariate analysis and cox proportional hazard regression modeling identified age, gender, smoking and drinking habits, dietary score, physical activity, shift work, exposure to high temperatures, occupational stress, and carbon monoxide exposure as key factors in the development of obesity in steelworkers. Test results indicated accuracies of 0.819, 0.868, and 0.872 for XG Boost, SVM, and RF respectively. Precision rates were 0.571, 0.696, and 0.765, while recall rates were 0.333, 0.592, and 0.481. The models achieved AUCs of 0.849, 0.908, and 0.912, with Brier scores of 0.128, 0.105, and 0.104, log losses of 0.409, 0.349, and 0.345, and calibration-in-the-large of 0.058, 0.054, and 0.051, respectively. Among these, the Random Forest model demonstrated superior performance.

CONCLUSIONS

The research indicates that obesity in steelworkers results from a combination of occupational and lifestyle factors. Of the models tested, the Random Forest model exhibited superior predictive ability, highlighting its significant practical application.

GPER/PKA-Dependent Enhancement of Hormone-Sensitive Lipase Phosphorylation in 3T3-L1 Adipocytes by Piceatannol

We previously reported that piceatannol (PIC) had an anti-obesity effect only in ovariectomized (OVX) postmenopausal obesity mice. PIC was found to induce the phosphorylation of hormone-sensitive lipase (pHSL) in OVX mice. To elucidate the mechanism by which PIC activates HSL, we investigated the effect of PIC using 3T3-L1 adipocytes. PIC induced HSL phosphorylation at Ser563 in 3T3-L1 cells, as in vivo experiments showed. pHSL (Ser563) is believed to be activated through the β-adrenergic receptor (β-AR) and protein kinase A (PKA) pathways; however, the addition of a selective inhibitor of β-AR did not inhibit the effect of PIC. The addition of a PKA inhibitor with PIC blocked pHSL (Ser563), suggesting that the effects are mediated by PKA in a different pathway than β-AR. The addition of G15, a selective inhibitor of the G protein-coupled estrogen receptor (GPER), reduced the activation of HSL by PIC. Furthermore, PIC inhibited insulin signaling and did not induce pHSL (Ser565), which represents its inactive form. These results suggest that PIC acts as a phytoestrogen and phosphorylates HSL through a novel pathway that activates GPER and its downstream PKA, which may be one of the inhibitory actions of PIC on fat accumulation in estrogen deficiency.

The Influence of Sex Hormones in Liver Function and Disease

The liver performs a multitude of bodily functions, whilst retaining the ability to regenerate damaged tissue. In this review, we discuss sex steroid biology, regulation of mammalian liver physiology and the development of new model systems to improve our understanding of liver biology in health and disease. A major risk factor for the development of liver disease is hepatic fibrosis. Key drivers of this process are metabolic dysfunction and pathologic activation of the immune system. Although non-alcoholic fatty liver disease (NAFLD) is largely regarded as benign, it does progress to non-alcoholic steatohepatitis in a subset of patients, increasing their risk of developing cirrhosis and hepatocellular carcinoma. NAFLD susceptibility varies across the population, with obesity and insulin resistance playing a strong role in the disease development. Additionally, sex and age have been identified as important risk factors. In addition to the regulation of liver biochemistry, sex hormones also regulate the immune system, with sexual dimorphism described for both innate and adaptive immune responses. Therefore, sex differences in liver metabolism, immunity and their interplay are important factors to consider when designing, studying and developing therapeutic strategies to treat human liver disease. The purpose of this review is to provide the reader with a general overview of sex steroid biology and their regulation of mammalian liver physiology.

Aluminum as a Possible Cause Toward Dyslipidemia

Aluminum, the third most abundant metal present in the earth's crust, is present almost in all daily commodities we use, and exposure to it is unavoidable. The interference of aluminum with various biochemical reactions in the body leads to detrimental health effects, out of which aluminum-induced neurodegeneration is widely studied. However, the effect of aluminum in causing dyslipidemia cannot be neglected. Dyslipidemia is a global health problem, which commences to the cosmic of non-communicable diseases. The interference of aluminum with various iron-dependent enzymatic activities in the tri-carboxylic acid cycle and electron transport chain results in decreased production of mitochondrial adenosine tri-phosphate. This ultimately contributes to oxidative stress and iron-mediated lipid peroxidation. This mitochondrial dysfunction along with modulation of α-ketoglutarate and L-carnitine perturbs lipid metabolism, leading to the atypical accumulation of lipids and dyslipidemia. Respiratory chain disruption because of the accumulation of reduced nicotinamide adenine di-nucleotide as a consequence of oxidative stress and the stimulatory effect of aluminum exposure on glycolysis causes many health issues including fat accumulation, obesity, and other hepatic disorders. One major factor contributing to dyslipidemia and enhanced pro-inflammatory responses is estrogen. Aluminum, being a metalloestrogen, modulates estrogen receptors, and in this world of industrialization and urbanization, we could corner down to metals, particularly aluminum, in the development of dyslipidemia. As per PRISMA guidelines, we did a literature search in four medical databases to give a holistic view of the possible link between aluminum exposure and various biochemical events leading to dyslipidemia.

Caffeine ameliorates the metabolic syndrome in diet-induced obese mice through regulating the gut microbiota and serum metabolism

OBJECTIVE

Obesity is associated with gut microbiota disorders, which has been related to developing metabolic syndromes. The research aims to investigate the effects of caffeine treatment on insulin resistance, intestinal microbiota composition and serum metabolomic changes in high-fat diet (HFD)-induced obesity mice.

METHODS

Eight-week-old male C57BL/6 J mice were fed a normal chow diet (NCD) or HFD with or without different concentrations of caffeine. After 12 weeks of treatment, body weight, insulin resistance, serum lipid profiles, gut microbiota and serum metabolomic profiles were assessed.

RESULTS

Caffeine intervention improved the metabolic syndrome in HFD-fed mice, such as serum lipid disorders and insulin resistance. 16S rRNA Sequencing analysis revealed that caffeine increased the relative abundance of Dubosiella, Bifidobacterium and Desulfovibrio and decreased that of Bacteroides, Lactobacillus and Lactococcus to reverse HFD-fed obesity in mice. Additionally, Caffeine Supplementation also altered serum metabolomics, mainly focusing on lipid metabolism, bile acid metabolism and energy metabolism. Caffeine increased its metabolite 1,7-Dimethylxanthine, which was positively correlated with Dubosiella.

CONCLUSIONS

Caffeine exerts a beneficial effect on insulin resistance in HFD-mice, and the underlying mechanism may be partly related to altered gut microbiota and bile acid metabolism.

Caffeine Ameliorates the Metabolic Syndrome in Diet-induced Obese Mice Through Regulating the Gut Microbiota and Serum Metabolism.. [DOI: 10.21203/rs.3.rs-1897181/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Objective Obesity is associated with gut microbiota disorders, which has been related to developing metabolic syndromes. The research aims to investigate the effects of caffeine treatment on insulin resistance, intestinal microbiota composition and serum metabolomic changes in high-fat diet (HFD)-induced obesity mice. Methods Eight-week-old male C57BL/6J mice were fed a normal chow diet (NCD) or HFD with or without different concentrations of caffeine. After 12 weeks of treatment, body weight, insulin resistance, serum lipid profiles, gut microbiota and serum metabolomic profiles were assessed. Results Caffeine intervention improved the metabolic syndrome in HFD-fed mice, such as serum lipid disorders and insulin resistance. 16S rRNA Sequencing analysis revealed that caffeine increased the relative abundance of Dubosiella, Bifidobacterium and Desulfovibrio and decreased that of Bacteroides, Lactobacillus and Lactococcus to reverse HFD-fed obesity in mice. Additionally, Caffeine Supplementation also altered serum metabolomics, mainly focusing on lipid metabolism, bile acid metabolism and energy metabolism. Caffeine increased its metabolite 1,7-Dimethylxanthine, which was positively correlated with Dubosiella. Conclusions Caffeine exerts a beneficial effect on insulin resistance in HFD-mice, and the underlying mechanism may be partly related to altered gut microbiota and bile acid metabolism.

Insight into Potential Interactions of Thyroid Hormones, Sex Hormones and Their Stimulating Hormones in the Development of Non-Alcoholic Fatty Liver Disease

Non-Alcoholic Fatty Liver Disease (NAFLD) is a common manifestation of metabolic syndrome. In addition to lifestyle, endocrine hormones play a role in the dysregulation of hepatic metabolism. The most common endocrine hormones contributing to metabolic syndrome are alterations in the levels of thyroid hormones (THs, predominantly in subclinical hypothyroidism) and of sex hormones (in menopause). These hormonal changes influence hepatic lipid and glucose metabolism and may increase hepatic fat accumulation. This review compares the effects of sex hormones, THs and the respective stimulating hormones, Thyroid-Stimulating Hormone (TSH) and Follicle-Stimulating Hormone (FSH), on the development of hepatosteatosis. TSH and FSH may be more relevant to the dysregulation of hepatic metabolism than the peripheral hormones because metabolic changes were identified when only levels of the stimulating hormones were abnormal and the peripheral hormones were still in the reference range. Increased TSH and FSH levels appear to have additive effects on the development of NAFLD and to act independently from each other.

17β-Estradiol Treatment Improves Acetylcholine-Induced Relaxation of Mesenteric Arteries in Ovariectomized UC Davis Type 2 Diabetes Mellitus Rats in Prediabetic State

We recently reported sex differences in mesenteric arterial function of the UC Davis type-2 diabetes mellitus (UCD-T2DM) rats as early as the prediabetic state. We reported that mesenteric arteries (MA) from prediabetic male rats exhibited a greater impairment compared to that in prediabetic females. However, when females became diabetic, they exhibited a greater vascular dysfunction than males. Thus, the aim of this study was to investigate whether the female sex hormone, estrogen preserves mesenteric arterial vasorelaxation in UCD-T2DM female rats at an early prediabetic state. Age-matched female Sprague Dawley and prediabetic (PD) UCD-T2DM rats were ovariectomized (OVX) and subcutaneously implanted with either placebo or 17β-estradiol (E_2, 1.5 mg) pellets for 45 days. We assessed the contribution of endothelium-derived relaxing factors (EDRF) to acetylcholine (ACh)-induced vasorelaxation, using pharmacological inhibitors. Responses to sodium nitroprusside (SNP) and phenylephrine (PE) were also measured. Additionally, metabolic parameters and expression of some targets associated with vascular and insulin signaling were determined. We demonstrated that the responses to ACh and SNP were severely impaired in the prediabetic state (PD OVX) rats, while E₂ treatment restored vasorelaxation in the PD OVX + E₂. Moreover, the responses to PE was significantly enhanced in MA of PD OVX groups, regardless of placebo or E₂ treatment. Overall, our data suggest that 1) the impairment of ACh responses in PD OVX rats may, in part, result from the elevated contractile responses to PE, loss of contribution of endothelium-dependent hyperpolarization (EDH) to vasorelaxation, and a decreased sensitivity of MA to nitric oxide (NO), and 2) the basis for the protective effects of E₂ may be partly attributed to the elevation of the NO contribution to vasorelaxation and its interaction with MA as well as potential improvement of insulin signaling. Here, we provide the first evidence of the role of E₂ in protecting MA from early vascular dysfunction in prediabetic female rats.

Dysmetabolism and Neurodegeneration: Trick or Treat?

Accumulating evidence suggests the existence of a strong link between metabolic syndrome and neurodegeneration. Indeed, epidemiologic studies have described solid associations between metabolic syndrome and neurodegeneration, whereas animal models contributed for the clarification of the mechanistic underlying the complex relationships between these conditions, having the development of an insulin resistance state a pivotal role in this relationship. Herein, we review in a concise manner the association between metabolic syndrome and neurodegeneration. We start by providing concepts regarding the role of insulin and insulin signaling pathways as well as the pathophysiological mechanisms that are in the genesis of metabolic diseases. Then, we focus on the role of insulin in the brain, with special attention to its function in the regulation of brain glucose metabolism, feeding, and cognition. Moreover, we extensively report on the association between neurodegeneration and metabolic diseases, with a particular emphasis on the evidence observed in animal models of dysmetabolism induced by hypercaloric diets. We also debate on strategies to prevent and/or delay neurodegeneration through the normalization of whole-body glucose homeostasis, particularly via the modulation of the carotid bodies, organs known to be key in connecting the periphery with the brain.

Expression of HK2, PKM2, and PFKM Is Associated with Metastasis and Late Disease Onset in Breast Cancer Patients

The reprogramming of energy metabolism is one of the hallmarks of cancer and is crucial for tumor progression. Altered aerobic glycolysis is a well-known characteristic of cancer cell metabolism. In the present study, the expression profiles of key metabolic genes (HK2, PFKM, and PKM2) were assessed in the breast cancer cohort of Pakistan using quantitative polymerase chain reaction (qPCR) and IHC. Expression patterns were correlated with molecular subtypes and clinical parameters in the patients. A significant upregulation of key glycolytic genes was observed in tumor samples in comparison to their adjacent controls (p < 0.0001). The expression of the studied glycolytic genes was significantly increased in late clinical stages, positive nodal involvement, and distant metastasis (p < 0.05). HK2 and PKM2 were found to be upregulated in luminal B, whereas PFKM was overexpressed in the luminal A subtype of breast cancer. The genes were positively correlated with the proliferation marker Ki67 (p < 0.001). Moreover, moderate positive linear correlations between HK2 and PKM2 (r = 0.476), HK2 and PFKM (r = 0.473), and PKM2 and PFKM (r = 0.501) were also observed (p < 0.01). These findings validate that the key regulatory genes in glycolysis can serve as potential biomarkers and/or molecular targets for breast cancer management. However, the clinical significance of these molecules needs to be further validated through in vitro and in vivo experiments.

Physiological and metabolic effects of healthy female aging on exhaled breath biomarkers

Healthy aging driven physio-metabolic events in females hold the key to complex in vivo mechanistic links and systemic cross talks. Effects from basic changes at genome, proteome, metabolome, and lipidome levels are often reflected at the upstream phenome (e.g., breath volatome) cascades. Here, we have analyzed exhaled volatile metabolites (measured via real time mass spectrometry based breathomics) data from 204 healthy females, aged between 07 and 80 years. Age related substance-specific differences were observed in breath biomarkers. Exhalation of blood-borne endogenous organosulfur, short-chain fatty acids, alcohols, aldehydes, alkene, ketones and exogenous nitriles, terpenes, and aromatics have denominated interplay between endocrine differences, energy homeostasis, systemic microbial diversity, oxidative stress, and lifestyle. Overall marker expressions were suppressed under daily oral contraception. Young homosexual/lesbian adults turned out as breathomic outliers. Previously proposed disease-specific breath biomarkers should be reevaluated upon aging effects. Breathomics offers a noninvasive window toward system-wide understanding and personalized monitoring of aging i.e., translatable to gerontology.

Oxysterols Profile in Zebrafish Embryos Exposed to Triclocarban and Propylparaben-A Preliminary Study

Oxysterols have long been considered as simple by-products of cholesterol metabolism, but they are now fully designed as bioactive lipids that exert their multiple effects through their binding to several receptors, representing endogenous mediators potentially involved in several metabolic diseases. There is also a growing concern that metabolic disorders may be linked with exposure to endocrine-disrupting chemicals (EDCs). To date, there are no studies aimed to link EDCs exposure to oxysterols perturbation-neither in vivo nor in vitro studies. The present research aimed to evaluate the differences in oxysterols levels following exposure to two metabolism disrupting chemicals (propylparaben (PP) and triclocarban (TCC)) in the zebrafish model using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Following exposure to PP and TCC, there were no significant changes in total and individual oxysterols compared with the control group; however, some interesting differences were noticed: 24-OH was detected only in treated zebrafish embryos, as well as the concentrations of 27-OH, which followed a different distribution, with an increase in TCC treated embryos and a reduction in zebrafish embryos exposed to PP at 24 h post-fertilization (hpf). The results of the present study prompt the hypothesis that EDCs can modulate the oxysterol profile in the zebrafish model and that these variations could be potentially involved in the toxicity mechanism of these emerging contaminants.

The role of mtDNA haplogroups on metabolic features in narcolepsy type 1

Narcolepsy type 1 (NT1) is due to selective loss of hypocretin (hcrt)-producing-neurons. Hcrt is a neuropeptide regulating the sleep/wake cycle, as well as feeding behavior. A subset of NT1 patients become overweight/obese, with a dysmetabolic phenotype. We hypothesized that mitochondrial DNA (mtDNA) sequence variation might contribute to the metabolic features in NT1 and we undertook an exploratory survey of mtDNA haplogroups in a cohort of well-characterized patients. We studied 246 NT1 Italian patients, fully defined for their metabolic features, including obesity, hypertension, low HDL, hypertriglyceridemia and hyperglycemia. For haplogroup assignment, the mtDNA control region was sequenced in combination with an assessment of diagnostic markers in the coding region. NT1 patients displayed the same mtDNA haplogroups (H, HV, J, K, T, U) frequency as those reported in the general Italian population. The majority of NT1 patients (64%) were overweight: amongst these, 35% were obese, 48% had low HDL cholesterol levels, and 31% had hypertriglyceridemia. We identified an association between haplogroups J, K and hypertriglyceridemia (P=0.03, 61.5% and 61.5%, respectively vs. 31.3% of the whole sample) and after correction for age and sex, we observed a reduction of these associations (OR=3.65, 95%CI=0.76-17.5, p=0.106 and 1.73, 0.52-5.69, p=0.368, respectively). The low HDL level showed a trend for association with haplogroup J (P=0.09, 83.3% vs. 47.4% of the whole sample) and after correction we observed an OR=6.73, 95%CI=0.65-69.9, p=0.110. Our study provides the first indication that mtDNA haplogroups J and K can modulate metabolic features of NT1 patients, linking mtDNA variation to the dysmetabolic phenotype in NT1.

Epigenetic Reprogramming of the Glucose Metabolic Pathways by the Chromatin Effectors During Cancer

Glucose metabolism plays a vital role in regulating cellular homeostasis as it acts as the central axis for energy metabolism, alteration in which may lead to serious consequences like metabolic disorders to life-threatening diseases like cancer. Malignant cells, on the other hand, help in tumor progression through abrupt cell proliferation by adapting to the changed metabolic milieu. Metabolic intermediates also vary from normal cells to cancerous ones to help the tumor manifestation. However, metabolic reprogramming is an important phenomenon of cells through which they try to maintain the balance between normal and carcinogenic outcomes. In this process, transcription factors and chromatin modifiers play an essential role to modify the chromatin landscape of important genes related directly or indirectly to metabolism. Our chapter surmises the importance of glucose metabolism and the role of metabolic intermediates in the cell. Also, we summarize the influence of histone effectors in reprogramming the cancer cell metabolism. An interesting aspect of this chapter includes the detailed methods to detect the aberrant metabolic flux, which can be instrumental for the therapeutic regimen of cancer.

Investigating the role of endogenous estrogens, hormone replacement therapy, and blockade of estrogen receptor-α activity on breast metabolic signaling

Purpose

Menopause is associated with an increased risk of estrogen receptor-positive (ER +) breast cancer. To characterize the metabolic shifts associated with reduced estrogen bioavailability on breast tissue, metabolomics was performed from ovary-intact and ovariectomized (OVX) female non-human primates (NHP). The effects of exogenous estrogen administration or estrogen receptor blockade (tamoxifen treatment) on menopause-induced metabolic changes were also investigated.

Methods

Bilateral ovariectomies were performed on female cynomolgus macaques (Macaca fascicularis) to model menopause. OVX NHP were then divided into untreated (n = 13), conjugated equine estrogen (CEE)-treated (n= 13), or tamoxifen-treated (n = 13) subgroups and followed for 3 years. Aged-matched ovary-intact female NHP (n = 12) were used as a premenopausal comparison group. Metabolomics was performed on snap-frozen breast tissue.

Results

Changes in several different metabolic biochemicals were noted, particularly in glucose and fatty acid metabolism. Specifically, glycolytic, Krebs cycle, acylcarnitines, and phospholipid metabolites were elevated in breast tissue from ovary-intact NHP and OVX + CEE in relation to the OVX and OVX + tamoxifen group. In contrast, treatment with CEE and tamoxifen decreased several cholesterol metabolites, compared to the ovary-intact and OVX NHP. These changes were accompanied by elevated bile acid metabolites in the ovary-intact group.

Conclusion

Alterations in estrogen bioavailability are associated with changes in the mammary tissue metabolome, particularly in glucose and fatty acid metabolism. Changes in these pathways may represent a bioenergetic shift in gland metabolism at menopause that may affect breast cancer risk.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06354-w.

Chronic DDE Exposure Modifies Mitochondrial Respiration during Differentiation of Human Adipose-Derived Mesenchymal Stem Cells into Mature Adipocytes

The contribution of environmental pollutants to the obesity pandemic is still not yet fully recognized. Elucidating possible cellular and molecular mechanisms of their effects is of high importance. Our study aimed to evaluate the effect of chronic, 21-day-long, 2,2-bis (4-chlorophenyl)-1,1-dichlorethylenedichlorodiphenyldichloroethylene (p,p´-DDE) exposure of human adipose-derived mesenchymal stem cells committed to adipogenesis on mitochondrial oxygen consumption on days 4, 10, and 21. In addition, the mitochondrial membrane potential (MMP), the quality of the mitochondrial network, and lipid accumulation in maturing cells were evaluated. Compared to control differentiating adipocytes, exposure to p,p´-DDE at 1 μM concentration significantly increased basal (routine) mitochondrial respiration, ATP-linked oxygen consumption and MMP of intact cells on day 21 of adipogenesis. In contrast, higher pollutant concentration seemed to slow down the gradual increase in ATP-linked oxygen consumption typical for normal adipogenesis. Organochlorine p,p´-DDE did not alter citrate synthase activity. In conclusion, in vitro 1 μM p,p´-DDE corresponding to human exposure is able to increase the mitochondrial respiration per individual mitochondrion at the end of adipocyte maturation. Our data reveal that long-lasting exposure to p,p´-DDE could interfere with the metabolic programming of mature adipocytes.

Combined Beneficial Effect of Genistein and Atorvastatin on Adipogenesis in 3T3-L1 Adipocytes

Genistein (4,5,7-trihydroxyisoflavone) is abundant in various dietary vegetables, especially soybeans, and is known to have not only an estrogenic effect but also an antiadipogenic effect. Atorvastatin (dihydroxy monocarboxylic acid) is a statin used to prevent heart disease. Although genistein and atorvastatin have been reported to possess antiadipogenic effects, their combined effects are still unclear. The aim of the current study was to explore whether the combination of genistein and atorvastatin at low concentrations significantly suppresses adipogenesis in a murine preadipocyte cell line (3T3-L1) compared to treatment with genistein or atorvastatin alone. Our results showed that cotreatment with 50 µM genistein and 50 nM atorvastatin significantly suppressed preadipocyte differentiation, whereas when each compound was used alone, there was no inhibitory effect. Additionally, cotreatment with genistein and atorvastatin significantly downregulated adipogenic marker proteins, including mitogen-activated protein kinases (MAPKs), peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein alpha (C/EBPα), glucocorticoid receptor (GR), and CCAAT/enhancer-binding protein β (C/EBPβ). This is the first evidence of the combined antiadipogenic effects of genistein and atorvastatin. Although additional experiments are required, combinational treatment with genistein and atorvastatin may be an alternative treatment for menopause-associated lipid metabolic disorders and obesity.

Sex hormones regulate lipid metabolism in adult Sertoli cells: A genome-wide study of estrogen and androgen receptor binding sites

Optimal functioning of Sertoli cells is crucial for spermatogenesis which is under tight regulation of sex hormones, estrogen and androgen. Adult rat Sertoli cells expresses estrogen receptor beta (ERβ) and androgen receptor (AR), both of which regulate gene transcription by binding to the DNA. The present study is aimed to acquire a genome-wide map of estrogen- and androgen-regulated genes in adult Sertoli cells. ChIP-Seq was performed for ERβ and AR in Sertoli cells under physiological conditions. 30,859 peaks in ERβ and 9,594 peaks in AR were identified with a fold enrichment >2 fold. Pathway analysis for the genes revealed metabolic pathways to be significantly enriched. Since Sertoli cells have supportive functions and provide energy substrates to germ cells during spermatogenesis, significantly enriched metabolic pathways were explored further. Peaks of the genes involved in lipid metabolism, like fatty acid, glyceride, leucine, and sphingosine metabolism were validated. Motif analysis confirmed the presence of estrogen- and androgen-response elements (EREs and AREs). Moreover, transcript levels of enzymes involved in the lipid metabolic pathways were significantly altered in cultured Sertoli cells treated with estrogen and androgen receptor agonists, demonstrating functional significance of these binding sites. This study elucidates a mechanism by which sex hormones regulate lipid metabolism in Sertoli cells by transcriptionally controlling the expression of these genes, thereby shedding light on the roles of these hormones in male fertility.

Endocrine disrupting chemicals (EDCs) and sex steroid receptors

Sex-steroid receptors (SSRs) are essential mediators of estrogen, progestin, and androgen signaling that are critical in vast aspects of human development and multi-organ homeostasis. Dysregulation of SSR function has been implicated in numerous pathologies including cancers, obesity, Type II diabetes mellitus, neuroendocrine disorders, cardiovascular disease, hyperlipidemia, male and female infertility, and other reproductive disorders. Endocrine disrupting chemicals (EDCs) modulate SSR function in a wide variety of cell and tissues. There exists strong experimental, clinical, and epidemiological evidence that engagement of EDCs with SSRs may disrupt endogenous hormone signaling leading to physiological abnormalities that may manifest in disease. In this chapter, we discuss the molecular mechanisms by which EDCs interact with estrogen, progestin, and androgen receptors and alter SSR functions in target cells. In addition, the pathological consequences of disruption of SSR action in reproductive and other organs by EDCs is described with an emphasis on underlying mechanisms of receptors dysfunction.

Low socioeconomic status aggravated associations of exposure to mixture of air pollutants with obesity in rural Chinese adults: A cross-sectional study

OBJECTIVES

Socio-economic status (SES) and air pollutants are thought to play an important role in human obesity. The evidence of interactive effect between SES and long-term exposure to mixture of air pollutants on obesity is limited, thus, this study is aimed to investigate their interactive effects on obesity among a rural Chinese population.

METHODS

A total of 38,817 individuals were selected from the Henan Rural Cohort Study. Structural equation modeling (SEM) was applied to construct the latent variables of low SES (educational level, marital status, family yearly income, and number of family members), air pollution (particulate matter with aerodynamics diameters ≤ 1.0 μm, ≤ 2.5 μm or ≤ 10 μm, and nitrogen dioxide) and obesity (body mass index, waist circumference, waist-to-hip ratio, waist-to-height ratio, body fat percentage and visceral fat index). Generalized linear regression models were used to assess associations between the constructed latent variables. Interaction plots were applied to describe interactive effect of air pollution and low SES on obesity and biological interaction indicators (the relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP) and synergy index (S)) were also calculated.

RESULTS

Increased latent variables of low SES and mixture of air pollution were associated with a higher odds of latent variable of obesity (odds ratios (OR) (95% confidence interval (CI)) were 1.055 (1.049, 1.060) and 1.050 (1.045, 1.055)). The association of the mixture of air pollutants on obesity was aggravated by increased values of the latent variable of low SES (P < 0.001). Furthermore, the values of RERI, AP and S were 0.073 (0.051, 0.094), 0.057 (0.040, 0.073) and 1.340 (1.214, 1.479), respectively, indicating an additive effect of estimated latent variable of low SES and air pollution on obesity.

CONCLUSIONS

These findings suggested that low SES aggravated the negative effect of mixture of air pollutants on obesity, implying that individuals with low SES may be more susceptible to exposure to high levels of mixture of air pollutants related to increased risk of prevalent obesity.

The Postnatal Offspring of Finasteride-Treated Male Rats Shows Hyperglycaemia, Elevated Hepatic Glycogen Storage and Altered GLUT2, IR, and AR Expression in the Liver

Background: A growing body of data indicates that the physiology of the liver is sex-hormone dependent, with some types of liver failure occurring more frequently in males, and some in females. In males, in physiological conditions, testosterone acts via androgen receptors (AR) to increase insulin receptor (IR) expression and glycogen synthesis, and to decrease glucose uptake controlled by liver-specific glucose transporter 2 (GLUT-2). Our previous study indicated that this mechanism may be impaired by finasteride, a popular drug used in urology and dermatology, inhibiting 5α-reductase 2, which converts testosterone (T) into dihydrotestosterone (DHT). Our research has also shown that the offspring of rats exposed to finasteride have an altered T–DHT ratio and show changes in their testes and epididymides. Therefore, the goal of this study was to assess whether the administration of finasteride had an trans-generational effect on (i) GLUT-2 dependent accumulation of glycogen in the liver, (ii) IR and AR expression in the hepatocytes of male rat offspring, (iii) a relation between serum T and DHT levels and the expression of GLUT2, IR, and AR mRNAs, (iv) a serum glucose level and it correlation with GLUT-2 mRNA. Methods: The study was conducted on the liver (an androgen-dependent organ) from 7, 14, 21, 28, and 90-day old Wistar male rats (F1:Fin) born by females fertilized by finasteride-treated rats. The control group was the offspring (F1:Control) of untreated Wistar parents. In the histological sections of liver the Periodic Acid Schiff (PAS) staining (to visualize glycogen) and IHC (to detect GLUT-2, IR, and AR) were performed. The liver homogenates were used in qRT-PCR to assess GLUT2, IR, and AR mRNA expression. The percentage of PAS-positive glycogen areas were correlated with the immunoexpression of GLUT-2, serum levels of T and DHT were correlated with GLUT-2, IR, and AR transcript levels, and serum glucose concentration was correlated with the age of animals and with the GLUT-2 mRNA by Spearman’s rank correlation coefficients. Results: In each age group of F1:Fin rats, the accumulation of glycogen was elevated but did not correlate with changes in GLUT-2 expression. The levels of GLUT-2, IR, and AR transcripts and their immunoreactivity statistically significantly decreased in F1:Fin animals. In F1:Fin rats the serum levels of T and DHT negatively correlated with androgen receptor mRNA. The animals from F1:Fin group have statistically elevated level of glucose. Additionally, in adult F1:Fin rats, steatosis was observed in the liver (see Appendix A). Conclusions: It seems that treating male adult rats with finasteride causes changes in the carbohydrate metabolism in the liver of their offspring. This can lead to improper hepatic energy homeostasis or even hyperglycaemia, insulin resistance, as well as some symptoms of metabolic syndrome and liver steatosis.

Analysis of Serum Metabolomics in Obese Mice Induced by High-Fat Diet

BACKGROUND

Obesity is a public health problem all over the world, and dietary habits are considered one of the important reasons.

METHODS

In this study, serum metabolites of mice fed a normal or high-fat diet (HFD) were analyzed using UPLC-QTOF-MS.

RESULTS

A significant increase in body weight was noted in HFD mice. The HFD and control groups were significantly different from each other on OPLS-DA scores. The major metabolites contributing to obesity were lipid metabolites (phosphatidylcholines, phosphatidylethanolamine, and lysophosphatidylcholines). In addition, this study revealed that glycerophospholipid metabolism, α-linolenic acid metabolism, and linoleic acid metabolism were related to obesity and obesity-associated diseases.

CONCLUSION

These results can be used to better understand obesity and assess its risk, which will provide new ideas for treatment.

Crosstalk between the muscular estrogen receptor α and BDNF/TrkB signaling alleviates metabolic syndrome via 7,8-dihydroxyflavone in female mice

Objective

7,8-Dihydroxyflavone (7,8-DHF), a small molecular mimetic of brain-derived neurotrophic factor (BDNF), alleviates high-fat diet-induced obesity in female mice in a sex-specific manner by activating muscular tropomyosin-related kinase B (TrkB). However, the underlying molecular mechanism for this sex difference is unknown. Moreover, muscular estrogen receptor α (ERα) plays a critical role in metabolic diseases. Impaired ERα action is often accompanied by metabolic syndrome (MetS) in postmenopausal women. This study investigated whether muscular ERα is involved in the metabolic effects of 7,8-DHF.

Methods

For the in vivo studies, 72 female C57BL/6J mice were given a low-fat diet or high-fat diet, and both received daily intragastric administration of vehicle or 7,8-DHF for 24 weeks. The hypothalamic-pituitary-ovarian (HPO) axis function was assessed by investigating typical sex-related serum hormones and the ovarian reserve. Indicators of menopausal MetS, including lipid metabolism, insulin sensitivity, bone density, and serum inflammatory cytokines, were also evaluated. The expression levels of ERα and other relevant signaling molecules were also examined. In vitro, the molecular mechanism involved in the interplay of ERα and TrkB receptors was verified in differentiated C2C12 myotubes using several inhibitors and a lentivirus short hairpin RNA-knockdown strategy.

Results

Long-term oral administration of 7,8-DHF acted as a protective factor for the female HPO axis function, protecting against ovarian failure, earlier menopause, and sex hormone disorders, which was paralleled by the alleviation of MetS coupled with the production of ERα-rich, TrkB-activated, and uncoupling protein 1 (UCP1) high thermogenic skeletal muscle tissues. 7,8-DHF-stimulated transactivation of ERα at serine 118 (S118) and tyrosine 537 (Y537), which was crucial to activate the BDNF/TrkB signaling cascades. In turn, activation of BDNF/TrkB signaling was also required for the ligand-independent activation of ERα, especially at the Y537 phosphorylation site. In addition, Src family kinases played a core role in the interplay of ERα and TrkB, synergistically activating the signaling pathways related to energy metabolism.

Conclusions

These findings revealed a novel role of 7,8-DHF in protecting the function of the female HPO axis and activating tissue-specific ERα, which improves our understanding of this sex difference in 7,8-DHF-mediated maintenance of metabolic homeostasis and provides new therapeutic strategies for managing MetS in women.

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7,8-DHF improves hypothalamic-pituitary-ovarian axis function in mature adult female mice.

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7,8-DHF protects against ovarian failure and onset of earlier menopause.

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7,8-DHF-induced transactivation of ERα is crucial to activate BDNF/TrkB signaling cascades.

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7,8-DHF-induced activations of ERα and BDNF/TrkB signaling are interdependent.

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Src family kinases play a core role in the crosstalk of ERα and BDNF/TrkB signaling pathways.

Maternal organophosphate flame-retardant exposure alters offspring feeding, locomotor and exploratory behaviors in a sexually-dimorphic manner in mice

Increased usage of organophosphate flame retardants (OPFRs) has led to detectable levels in pregnant women and neonates, which is associated with negative neurological outcomes. Therefore, we investigated if maternal OPFR exposure altered adult offspring feeding, locomotor, and anxiety-like behaviors on a low-fat (LFD) or high-fat diet (HFD). Wild-type C57Bl/6J dams were orally dosed with vehicle (sesame oil) or an OPFR mixture (1 mg/kg combination each of tris(1,3-dichloro-2-propyl)phosphate, triphenyl phosphate and tricresyl phosphate) from gestation day 7 to postnatal day 14. After weaning, pups were fed either a LFD or HFD until 19 weeks of age. Locomotor and anxiety-like behaviors were evaluated with the open field test, elevated plus maze, and metabolic cages. Feeding behaviors and meal patterns were analyzed by a Biological Data Acquisition System. Anogenital distance was reduced in OPFR-exposed male pups, but no effect was detected on adult body weight. We observed interactions of OPFR exposure and HFD consumption on locomotor and anxiety-like behavior in males, suggesting an anxiogenic effect while reducing overall nighttime activity. We also observed an interaction of OPFR exposure and HFD on weekly food intake and feeding behaviors. OPFR-exposed males consumed more total HFD than oil-exposed males during the 72-hour trial. However, when arcuate gene expression was analyzed, OPFR exposure induced Agrp expression in females, which would suggest greater orexigenic tone. Collectively, the implications of our study are that the behavioral effects of OPFR exposure are modulated by adult HFD consumption, which may influence the metabolic and neurological consequences of maternal OPFR exposure.

Is obesity the missing link between COVID-19 severity and air pollution?

In the previous publication "Can atmospheric pollution be considered a co-factor in extremely high level of SARS-CoV-2 lethality in Northern Italy?" Conticini et al. hypothesized that the surplus of lethality of the novel SARS-CoV-2 in Northern Italy may be at least in part explained by the evidence of highest pollution reported in this area, as both severe COVID-19 and smog exposure are correlated to an innate immune system hyper-activation with subsequent lung inflammation and injury. Since this hypothesis alone does not fully explain why specific subgroups of patients are at major risk, we hypothesized that obesity may be one of the links between COVID-19 severity and high level of air pollution. First, obesity is a predisposing factor for SARS-Cov-2 infection and worse COVID-19 outcomes, and unequivocal evidence demonstrated that fat mass excess is independently associated with several pulmonary diseases and lung inflammation. Moreover, it has been shown that obesity may intensify the detrimental effects of air pollution on the lungs, and this is not surprising if we consider that these conditions share an excessive activation of the immune system and a lung inflammatory infiltrate. Finally, fat mass excess has also been speculated to be itself a consequence of air pollutants exposure, which has been proved to induce metabolic disruption and weight gain in murine models. In conclusion, although many variables must be taken into account in the analysis of the pandemic, our observations suggest that obesity may act as effect modifier of smog-induced lung-injury, and the concomitant presence of these two factors could better explain the higher virulence, faster spread and greater mortality of SARS-CoV-2 in Northern Italy compared to the rest of the country.

Effect of flaxseed oil on biochemical parameters, hormonal indexes and stereological changes in ovariectomized rats

The ovariectomized rat is a widely used preclinical model for studying postmenopausal and its complications. In this study, the therapeutic effect of flaxseed oil on the ovariectomized adult rats was investigated. Our results showed that biochemical parameters including calcium, oestrogen and progesterone levels increase 8 weeks after ovariectomy in rats. Also, the amount of alkaline phosphatase decreased significantly after 8 weeks compared with the OVX rat. The healing potential of flaxseed oil was proven by successfully recovering the affected tissue and preventing the unpleasant symptoms of ovariectomized rats. The biological effects of flaxseed oil may be due to high amounts of fatty acids, phytoestrogens and an array of antioxidants. The results suggest that flaxseed oil can mimic the action of oestrogen and can be a potential treatment for hormone replacement therapy (HRT).

The sex-specific association of phthalate exposure with DNA methylation and characteristics of body fat in children

The present study assessed the association between phthalate exposure and mitochondrial DNA (mtDNA) polymerase γ (POLG) methylation along with the potential effect on the characteristics of body fat in children. A total of 152 children were enrolled. The urinary concentrations of phthalate metabolites were measured using ultraperformance liquid chromatography-tandem mass spectrometry. Genomic DNA was extracted from the buffy coat, and bisulfite-treated DNA was subjected to a pyrosequencing assay. In total, 17 CpG sites in the exon 2 region of POLG were included in the analysis. A multivariable regression model was applied to determine whether characteristics of body fat were associated with phthalate exposure and methylation of POLG. After adjustment for covariates, male children with a ten-fold increase in mono-methyl phthalate (MMP) or mono-benzyl phthalate (MBzP) concentrations had significantly higher measurements for total body fat (MMP: β = 6.47%; MBzP: β = 3.54%), and trunk fat (MMP: β = 6.67%; MBzP: β = 3.90%). Male children who had hypermethylation at the 2nd CpG site in exon 2 of POLG also had high measurements for BMI (β = 1.66 kg/m2), waist (β = 4.49 cm) and hip (β = 4.81 cm) circumference, total body fat (β = 5.48%), and trunk fat (β = 6.21%). A dose-response relationship existed between methylation at the 2nd CpG site in exon 2 of POLG and characteristics of body fat (p for trend<0.01). This study suggested that male children who are exposed to phthalic acid esters have high body weight, BMI, and body and trunk fat percentages. Methylation of the exon 2 region of POLG is a possible mechanism behind the causal effect of endocrine-disrupting substances.

Long-term effects of western diet consumption in male and female mice

Long-term consumption of a diet with excessive fat and sucrose (Western diet, WD) leads to an elevated risk of obesity and metabolic syndrome in both males and females. However, there are sexual dimorphisms in metabolism which are apparent when considering the prevalence of complications of metabolic syndrome, such as non-alcoholic fatty liver disease. This study aimed to elucidate the impact of a WD on the metabolome and the gut microbiota of male and female mice at 5, 10, and 15 months to capture the dynamic and comprehensive changes brought about by diet at different stages of life. Here we show that there are important considerations of age and sex that should be considered when assessing the impact of diet on the gut microbiome and health.

Ovariectomized rodents as a menopausal metabolic syndrome model. A minireview

Bilateral ovariectomy is the best characterized and the most reported animal model of human menopause. Ovariectomized rodents develop insulin resistance (IR) and visceral obesity, the main risk factors in the pathophysiology of metabolic syndrome (MS). These alterations are a consequence of hypoestrogenic status, which produces an augment of visceral fat, high testosterone levels (hyperandrogenism), as well as inflammation, oxidative stress, and metabolic complications, such as dyslipidemia, hepatic steatosis, and endothelial dysfunction, among others. Clinical trials have reported that menopause per se increases the severity and incidence of MS, and causes the highest mortality due to cardiovascular disease in women. Despite all the evidence, there are no reports that clarify the influence of estrogenic deficiency as a cause of MS. In this review, we provide evidence that ovariectomized rodents can be used as a menopausal metabolic syndrome model for evaluating and discovering new, safe, and effective therapeutic approaches in the treatment of cardiometabolic complications associated to MS during menopause.

Sex-dimorphic moderate hypoglycemia preconditioning effects on Hippocampal CA1 neuron bio-energetic and anti-oxidant function

Hypoglycemia is a detrimental complication of rigorous management of type 1 diabetes mellitus. Moderate hypoglycemia (MH) preconditioning of male rats partially affords protection from loss of vulnerable brain neurons to severe hypoglycemia (SH). Current research investigated whether MH preconditioning exerts sex-dimorphic effects on hippocampal CA1 neuron bio-energetic and anti-oxidant responses to SH. SH up-regulated CA1 glucose or monocarboxylate transporter proteins in corresponding hypoglycemia-naïve male versus female rats; precedent MH amplified glucose transporter expression in SH irrespective of sex. Sex-differentiating SH effects on glycolytic and tricarboxylic pathway markers correlated with elevated tissue ATP content and diminished CA1 5'-AMP-activated protein kinase (AMPK) activation in females. MH-preconditioned suppression of mitochondrial energy pathway enzyme profiles and tissue ATP in SH rats coincided with amplified CA1 AMPK activity in both sexes. Anti-oxidative stress enzyme protein responses to SH were primarily sex-contingent; preconditioning amplified most of these profiles, yet exacerbated expression of lipid and protein oxidation markers in SH male and female rats, respectively. Results show that MH preconditioning abolishes female CA1 neuron neuroprotection of positive energy balance through SH, resulting in augmented CA1 AMPK activity and oxidative injury and diminished tissue ATP in hypoglycemia-conditioned versus naïve rats in each sex. It is unclear if SH elicits differential rates of CA1 neuronal destruction in the two sexes, or how MH may impact sex-specific cell loss. Further research is needed to determine if molecular mechanism(s) that maintain female CA1 neuron metabolic stability in the absence of MH preconditioning can be leveraged for therapeutic prevention of hypoglycemic nerve cell damage.

Estrogen exacerbates mammary involution through neutrophil-dependent and -independent mechanism

There is strong evidence that the pro-inflammatory microenvironment during post-partum mammary involution promotes parity-associated breast cancer. Estrogen exposure during mammary involution drives tumor growth through neutrophils’ activity. However, how estrogen and neutrophils influence mammary involution are unknown. Combined analysis of transcriptomic, protein, and immunohistochemical data in BALB/c mice showed that estrogen promotes involution by exacerbating inflammation, cell death and adipocytes repopulation. Remarkably, 88% of estrogen-regulated genes in mammary tissue were mediated through neutrophils, which were recruited through estrogen-induced CXCR2 signalling in an autocrine fashion. While neutrophils mediate estrogen-induced inflammation and adipocytes repopulation, estrogen-induced mammary cell death was via lysosome-mediated programmed cell death through upregulation of cathepsin B, Tnf and Bid in a neutrophil-independent manner. Notably, these multifaceted effects of estrogen are mostly mediated by ERα and unique to the phase of mammary involution. These findings are important for the development of intervention strategies for parity-associated breast cancer.

Four cypermethrin isomers induced stereoselective metabolism in H295R cells

Cypermethrin (CP) is widely used for controlling agricultural and indoor vermin. Previous studies have reported the stereoselective difference of CP in biological activities. However, little is known about their potential mechanisms between metabolic phenotypes and endocrine-disrupting effects. Herein, nuclear magnetic resonance (NMR)-based metabolomics combining metabolite identification and pathway analysis were applied to evaluate the stereoselective metabolic cdisorders induced by CP isomers in human adrenocortical carcinoma cells (H295R) culture medium. Then, gene expression levels related to disturbed metabolic pathways were assessed to verify according to metabolic phenotypes. Metabolomics profiles showed that [(S)-cyano(3-phenoxyphenyl)methyl](1R,3R)-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-1-carboxylate [(1R,3R,αS)-CP] induced the most significant changes in metabolic phenotypes than did the other stereoisomers. There are 10 differential metabolites (isoleucine, valine, leucine, ethanol, alanine, acetate, aspartate, arginine, lactate, and glucose) as well as two significantly disturbed pathways, including "pyruvate metabolism" and "alanine, aspartate, and glutamate metabolism," that were confirmed in H295R cells culture medium of (1R,3R,αS)-CP compared with other stereoisomers. Polymerase chain reaction (PCR) array also confirmed the results of metabolomics. Our results can help to understand the potential mechanisms between the isomer selectivity in metabolic phenotypes and endocrine-disrupting effects. Data provided here not only lend authenticity to the cautions issued by the scientists and researchers but also offer a solution for the balance between environment and political regulations.

Genome-wide identification of estrogen receptor binding sites reveals novel estrogen-responsive pathways in adult male germ cells

Spermatogenesis occurs in the seminiferous epithelium that shows the presence of estrogen receptors alpha (ERα) and beta (ERβ), both of which regulate gene transcription by binding to the DNA. Estrogen responsive phases of spermatogenesis are well documented; however, the genes regulated remain inexplicit. To study the regulation of genes by estrogen in male germ cells, we performed chromatin immunoprecipitation (ChIP) sequencing for ERα and ERβ under normal physiological conditions. A total of 27 221 DNA binding regions were enriched with ERα and 20 926 binding sites with ERβ. Majority of the peaks were present in the intronic regions and located 20 kb upstream or downstream from the transcription start site (TSS). Pathway analysis of the genes enriched by ChIP-Seq showed involvement in several biological pathways. Genes involved in pathways whose role in spermatogenesis is unexplored were validated; these included prolactin, GnRH, and oxytocin signaling. All the selected genes showed the presence of estrogen response elements (EREs) in their binding region and were also found to be significantly enriched by ChIP-qPCR. Functional validation using seminiferous tubule culture after treatment with estrogen receptor subtype-specific agonist and antagonist confirmed the regulation of these genes by estrogen through its receptors. The genes involved in these pathways were also found to be regulated by the respective receptor subtypes at the testicular level in our in vivo estrogen receptor agonist rat models. Our study provides a genome-wide map of ERα and ERβ binding sites and identifies the genes regulated by them in the male germ cells under normal physiological conditions.

Assessment of the potential ecological risk of residual endocrine-disrupting chemicals from wastewater treatment plants

Residual chemicals discharged from wastewater treatment plants (WWTPs) and subsequent ecological risk are important in production safety when reuse of the effluent water occurs. Thus, this work provides an investigation of the occurrence and removal of dissolved Endocrine-disrupting chemicals (EDCs) in 38 WWTPs in Guangdong Province, China. The results indicate that EDCs are widely distributed in the investigated WWTPs, while nonylphenols (NPs) are the predominant chemical among the target EDCs, accounting for >98% of the concentration in the influent and >97% of the concentration in the effluent. Moreover, 4 main types of wastewater treatment processes (oxidation ditch, A2/O, conventional activated sludge and microaeration oxidation ditch followed by A2/O) were found to be inefficient for removing dissolved EDCs, with a mean removal rate of approximately 25%. The potential environmental risk was predicted for residual EDCs. Specifically, 17α-ethynylestradiol (EE2) was considered to be the most hazardous chemical among the target EDCs, with a median risk quotient (RQ) of 8.94. In addition, β-estradiol (E2) and estrone (E1) have median RQs of 1.14 and 0.27, and NPs have median RQs of 0.61 (algae), 0.37 (inverberate) and 0.25 (fish), respectively.

Sex Hormone-Dependent Physiology and Diseases of Liver

Sexual dimorphism is associated not only with somatic and behavioral differences between men and women, but also with physiological differences reflected in organ metabolism. Genes regulated by sex hormones differ in expression in various tissues, which is especially important in the case of liver metabolism, with the liver being a target organ for sex hormones as its cells express estrogen receptors (ERs: ERα, also known as ESR1 or NR3A; ERβ; GPER (G protein-coupled ER, also known as GPR 30)) and the androgen receptor (AR) in both men and women. Differences in sex hormone levels and sex hormone-specific gene expression are mentioned as some of the main variations in causes of the incidence of hepatic diseases; for example, hepatocellular carcinoma (HCC) is more common in men, while women have an increased risk of autoimmune liver disease and show more acute liver failure symptoms in alcoholic liver disease. In non-alcoholic fatty liver disease (NAFLD), the distinction is less pronounced, but increased incidences are suggested among men and postmenopausal women, probably due to an increased tendency towards visceral fat accumulation.

Metabolomic profiling of dried blood spots reveals gender-specific discriminant models for the diagnosis of small cell lung cancer

The accurate diagnosis of small cell lung cancer (SCLC) at initial presentation is essential to ensure appropriate treatment. No validated blood biomarkers that could distinguish SCLC from non-small cell lung cancer (NSCLC) has yet been developed. Dried blood spot (DBS) microsampling has gained increasing interest in biomarkers discovery. In this study, we first performed metabolomic profiling of DBS samples from 37 SCLC, 40 NSCLC, and 37 controls. Two gender-specific multianalyte discriminant models were established for males and females, respectively to distinguish SCLC from NSCLC and controls. The receiver operator characteristic (ROC) curve analysis showed the diagnostic accuracy of 95% (95% CI: 83%-100%) in males SCLC using five metabolites in DBS and 94% (95% CI: 74%-100%) for females using another set of five metabolites. The robustness of the models was confirmed by the random permutation tests (P < 0.01 for both). The performance of the discriminant models was further evaluated using a validation cohort with 78 subjects. The developed discriminant models yielded an accuracy of 91% and 81% for males and females, respectively, in the validation cohort. Our results highlighted the potential clinical utility of the metabolomic profiling of DBS as a convenient and effective approach for the diagnosis of SCLC.

Mono-2-ethylhexyl phthalate (MEHP) promoted lipid accumulation via JAK2/STAT5 and aggravated oxidative stress in BRL-3A cells

Mono-2-ethylhexyl phthalate (MEHP), as the major metabolite of Di-(2-ethylhexyl) phthalate (DEHP), can induce lipid accumulation in hepatocytes and further leads to non-alcoholic fatty liver disease (NAFLD), while the underlying mechanism is unclear. We aim to clarify the effects of JAK2/STAT5 pathway on lipid accumulation induced by MEHP and the role of oxidation stress in NAFLD. BRL-3A hepatocytes were exposed to MEHP (0, 10, 50, 100 and 200 μM) for 24 h and 48 h. Then the lipid droplets in cells were observed by Oil-Red-O staining and quantified by isopropyl alcohol. The levels of TG, SOD, TBARS, AST and ALT were all detected by commercial kits. RT-PCR was used to detect mRNA expression, and western blotting was used to detect the expression of proteins encoded by JAK2/STAT5 pathway genes and lipid metabolism-related genes. As a result, MEHP promoted the lipid synthesis and accumulation in BRL-3A cells. MEHP down-regulated the expression and inhibited the activation of JAK2/STAT5. Moreover, the lipid metabolism-related kinases levels were elevated after MEHP exposure. In addition, the SOD levels were gradually decreased and the TBARS levels were increased in MEHP-treated groups. The lipid metabolism-related proteins levels were correlated with the oxidation stress levels. Furthermore, the ALT and AST levels were elevated after MEHP exposure. Therefore, we concluded that MEHP led to lipid accumulation through inhibiting JAK2/STAT5 pathway, resulted in damaging liver parenchyma and NAFLD by aggravating oxidation stress.

Examining the Impact of Estrogen on Binge Feeding, Food-Motivated Behavior, and Body Weight in Female Rats

OBJECTIVE

Binge-eating disorder is associated with diminished self-control, emotional distress, and obesity. In this context, women are nearly twice as likely to develop binge-eating disorder and depression relative to men. Here, the physiological, psychological, and endocrine parameters were characterized in female rats subjected to a binge-eating protocol.

METHODS

Nonrestricted female Long Evans rats (n = 8/group) received 2-hour restricted access to a high-fat diet (HFD) (4.54 kcal/g) every day or every third day. The progression of estrous cycling, the functional relevance of estrogen signaling for binge feeding, and binge-induced changes in food motivation were measured.

RESULTS

Female rats developed a binge pattern of feeding that included alternation between caloric overconsumption and compensatory voluntary restriction without impacting estrous cycling. Notably, rats that received daily HFD exposure progressively decreased binge meals. Estrogen replacement in normal cycling or ovariectomized rats mimicked the reduction in body weight in female rats that received daily HFD access. Operant responding was unaffected by binge feeding; however, estrogen augmented operant performance in HFD-exposed rats.

CONCLUSIONS

Collectively, these data suggest that estrogen protects against binge-induced increases in body weight gain without affecting food motivation in female rats.