Chronic exposure to low doses of pharmaceuticals disturbs the hepatic expression of circadian genes in lean and obese mice

Coagulation Factor VII Fine-tunes Hepatic Steatosis by Blocking AKT-CD36-Mediated Fatty Acid Uptake

Nonalcoholic fatty liver disease (NAFLD) is considered a risk factor for cardiovascular and cerebrovascular disease owing to its close association with coagulant disturbances. However, the precise biological functions and mechanisms that connect coagulation factors to NAFLD pathology remain inadequately understood. Herein, with unbiased bioinformatics analyses followed by functional testing, we demonstrate that hepatic expression of coagulation factor VII (FVII) decreases in patients and mice with NAFLD/nonalcoholic steatohepatitis (NASH). By using adenovirus-mediated F7-knockdown and hepatocyte-specific F7-knockout mouse models, our mechanistic investigations unveil a noncoagulant function of hepatic FVII in mitigating lipid accumulation and lipotoxicity. This protective effect is achieved through the suppression of fatty acid uptake, orchestrated via the AKT-CD36 pathway. Interestingly, intracellular FVII directly interacts with AKT and PP2A, thereby promoting their association and triggering the dephosphorylation of AKT. Therapeutic intervention through adenovirus-mediated liver-specific overexpression of F7 results in noteworthy improvements in liver steatosis, inflammation, injury, and fibrosis in severely afflicted NAFLD mice. In conclusion, our findings highlight coagulation factor FVII as a critical regulator of hepatic steatosis and a potential target for the treatment of NAFLD and NASH.

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Detection of Acetaminophen in Groundwater by Laccase-Based Amperometric Biosensors Using MoS2 Modified Carbon Paper Electrodes

The use of enzyme-based biosensors for the detection and quantification of analytes of interest such as contaminants of emerging concern, including over-the-counter medication, provides an attractive alternative compared to more established techniques. However, their direct application to real environmental matrices is still under investigation due to the various drawbacks in their implementation. Here, we report the development of bioelectrodes using laccase enzymes immobilized onto carbon paper electrodes modified with nanostructured molybdenum disulfide (MoS₂). The laccase enzymes were two isoforms (LacI and LacII) produced and purified from the fungus Pycnoporus sanguineus CS43 that is native to Mexico. A commercial purified enzyme from the fungus Trametes versicolor (TvL) was also evaluated to compare their performance. The developed bioelectrodes were used in the biosensing of acetaminophen, a drug widely used to relieve fever and pain, and of which there is recent concern about its effect on the environment after its final disposal. The use of MoS₂ as a transducer modifier was evaluated, and it was found that the best detection was achieved using a concentration of 1 mg/mL. Moreover, it was found that the laccase with the best biosensing efficiency was LacII, which achieved an LOD of 0.2 µM and a sensitivity of 0.108 µA/µM cm² in the buffer matrix. Moreover, the performance of the bioelectrodes in a composite groundwater sample from Northeast Mexico was analyzed, achieving an LOD of 0.5 µM and a sensitivity of 0.015 µA/µM cm². The LOD values found are among the lowest reported for biosensors based on the use of oxidoreductase enzymes, while the sensitivity is the highest currently reported.

Dysregulation of Lipid and Glucose Homeostasis in Hepatocyte-Specific SLC25A34 Knockout Mice

Nonalcoholic fatty liver disease (NAFLD) is an epidemic affecting 30% of the US population. It is characterized by insulin resistance, and by defective lipid metabolism and mitochondrial dysfunction in the liver. SLC25A34 is a major repressive target of miR-122, a miR that has a central role in NAFLD and liver cancer. However, little is known about the function of SLC25A34. To investigate SLC25A34 in vitro, mitochondrial respiration and bioenergetics were examined using hepatocytes depleted of Slc25a34 or overexpressing Slc25a34. To test the function of SLC25A34 in vivo, a hepatocyte-specific knockout mouse was generated, and loss of SLC25A34 was assessed in mice maintained on a chow diet and a fast-food diet (FFD), a model for NAFLD. Hepatocytes depleted of Slc25a34 displayed increased mitochondrial biogenesis, lipid synthesis, and ADP/ATP ratio; Slc25a34 overexpression had the opposite effect. In the knockout model on chow diet, SLC25A34 loss modestly affected liver function (altered glucose metabolism was the most pronounced defect). RNA-sequencing revealed changes in metabolic processes, especially fatty acid metabolism. After 2 months on FFD, knockouts had a more severe phenotype, with increased lipid content and impaired glucose tolerance, which was attenuated after longer FFD feeding (6 months). This work thus presents a novel model for studying SLC25A34 in vivo in which SLC25A34 plays a role in mitochondrial respiration and bioenergetics during NAFLD.

Endocrine disrupting chemicals and metabolic disorders in the liver: What if we also looked at the female side?

Endocrine disrupting chemicals (EDCs) are linked to the worldwide epidemic incidence of metabolic disorders and fatty liver diseases, which affects quality of life and represents a high economic cost to society. Energy homeostasis exhibits strong sexual dimorphic traits, and metabolic organs respond to EDCs depending on sex, such as the liver, which orchestrates both drug elimination and glucose and lipid metabolism. In addition, fatty liver diseases show a strong sexual bias, which in part could also originate from sex differences observed in gut microbiota. The aim of this review is to highlight significant differences in endocrine and metabolic aspects of the liver, between males and females throughout development and into adulthood. It is also to illustrate how the male and female liver differently cope with exposure to various EDCs such as bisphenols, phthalates and persistent organic chemicals in order to draw attention to the need to include both sexes in experimental studies. Interesting data come from analyses of the composition and diversity of the gut microbiota in males exposed to the mentioned EDCs showing significant correlations with hepatic lipid accumulation and metabolic disorders but information on females is lacking or incomplete. As industrialization increases, the list of anthropogenic chemicals to which humans will be exposed will also likely increase. In addition to strengthening existing regulations, encouraging populations to protect themselves and promoting the substitution of harmful chemicals with safe products, innovative strategies based on sex differences in the gut microbiota and in the gut-liver axis could be optimistic outlook.

Obesogenic Effect of Sulfamethoxazole on Drosophila melanogaster with Simultaneous Disturbances on Eclosion Rhythm, Glucolipid Metabolism, and Microbiota

Antibiotics have recently gained attention because they are emerging environmental pollutants with obesogenic properties. In this study, Drosophila melanogaster were exposed to sulfamethoxazole (SMX), a sulfonamide antibiotic, and the effects were measured on circadian rhythm (represented by the eclosion rhythm), lipid metabolism, and microbiota. Circadian rhythm disorder was considered due to its connection with lipid metabolism and microbiota in association with obesity. SMX decreased the proportion of adult flies that eclosed in the morning (AM adults) and increased the proportion of PM adults. Moreover, SMX increased the body weight of PM adults, indicating that SMX exposure caused dysrhythmia in eclosion together with obesity. In measurements of key metabolites and metabolic enzymes, SMX exposure stimulated 3 indices in AM adults and 10 indices in PM adults. In AMP-activated protein kinase and insulin/IGF-1 signaling pathways, SMX upregulated six genes in AM adults and nine genes in PM adults. Finally, microbiota analysis demonstrated that SMX increased the Firmicutes/Bacteroides ratios (F/B) by 79.6- and 5.8-fold compared to concurrent controls in AM and PM adults. Collectively, these results suggest that SMX showed obesogenic effects accompanied with dysrhythmia and disturbances in lipid metabolism and microbiota. Further studies on the intrinsic connection are needed.

Transcriptome analysis of the brain of the sea bream (Sparus aurata) after exposure to human pharmaceuticals at realistic environmental concentrations

Human pharmaceuticals such as Acetaminophen, Atenolol and Carbamazepine are pseudo persistent aquatic pollutants with yet unknown sub-lethal effects at environmentally relevant concentrations. Gilthead seabream (Sparus aurata) were exposed to Acetaminophen: 31.90 ± 11.07 μg L^-1; Atenolol: 0.95 ± 0.38 μg L^-1 and Carbamazepine: 6.95 ± 0.13 μg L^-1 in a 28 day flow through experiment to (1) determine whether exposure to low concentrations in the μg·L^-1 range of the pharmaceuticals alters the brain transcriptome and, (2) identify different expression profiles and treatment specific modes of action and pathways. Despite low exposure concentrations, 411, 7 and 612 differently expressed transcripts were identified in the individual treatments with Acetaminophen, Atenolol and Carbamazepine, respectively. Functional analyses of differentially expressed genes revealed a significant over representation of several biological processes, cellular compartment features and molecular functions for both Acetaminophen and Carbamazepine treatments. Overall, the results obtained in seabream brain suggest similar physiological responses to those observed in humans also at environmental concentrations, as well as the existence of treatment specific processes that may be useful for the development of biomarkers of contamination.

Chronic and low exposure to a pharmaceutical cocktail induces mitochondrial dysfunction in liver and hyperglycemia: Differential responses between lean and obese mice

Pharmaceuticals are found in the environment but the impact of this contamination on human and animal health is poorly known. The liver could be particularly targeted since a significant number of these drugs are hepatotoxic, in particular via oxidative stress and mitochondrial dysfunction. Notably, the latter events can also be observed in liver diseases linked to obesity, so that the obese liver might be more sensitive to drug toxicity. In this study, we determined the effects of a chronic exposure to low doses of pharmaceuticals in wild-type and obese mice, with a particular focus on mitochondrial function. To this end, wild-type and ob/ob mice were exposed for 4 months to a cocktail of 11 pharmaceuticals provided in drinking water containing 0.01, 0.1, or 1 mg/L of each drug. At the end of the treatment, liver mitochondria were isolated and different parameters were measured. Chronic exposure to the pharmaceuticals reduced mitochondrial respiration driven by succinate and palmitoyl-l-carnitine in wild-type mice and increased antimycin-induced ROS production in ob/ob mice. Hyperglycemia and hepatic histological abnormalities were also observed in treated ob/ob mice. Investigations were also carried out in isolated liver mitochondria incubated with the mixture, or with each individual drug. The mitochondrial effects of the mixture were different from those observed in treated mice and could not be predicted from the results obtained with each drug. Because some of the 11 drugs included in our cocktail can be found in water at relatively high concentrations, our data could be relevant in environmental toxicology. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1375-1389, 2017.

Generation of stomach tissue from mouse embryonic stem cells

Successful pluripotent stem cell differentiation methods have been developed for several endoderm-derived cells, including hepatocytes, β-cells and intestinal cells. However, stomach lineage commitment from pluripotent stem cells has remained a challenge, and only antrum specification has been demonstrated. We established a method for stomach differentiation from embryonic stem cells by inducing mesenchymal Barx1, an essential gene for in vivo stomach specification from gut endoderm. Barx1-inducing culture conditions generated stomach primordium-like spheroids, which differentiated into mature stomach tissue cells in both the corpus and antrum by three-dimensional culture. This embryonic stem cell-derived stomach tissue (e-ST) shared a similar gene expression profile with adult stomach, and secreted pepsinogen as well as gastric acid. Furthermore, TGFA overexpression in e-ST caused hypertrophic mucus and gastric anacidity, which mimicked Ménétrier disease in vitro. Thus, in vitro stomach tissue derived from pluripotent stem cells mimics in vivo development and can be used for stomach disease models.

Synthetic progestins medroxyprogesterone acetate and dydrogesterone and their binary mixtures adversely affect reproduction and lead to histological and transcriptional alterations in zebrafish (Danio rerio)

Medroxyprogesterone acetate (MPA) and dydrogesterone (DDG) are synthetic progestins widely used in human and veterinary medicine. Although aquatic organisms are exposed to them through wastewater and animal farm runoff, very little is known about their effects in the environment. Here we provide a comprehensive analysis of the responses of zebrafish (Danio rerio) to MPA, DDG, and their binary mixtures at measured concentrations between 4.5 and 1663 ng/L. DDG and both mixtures impaired reproductive capacities (egg production) of breeding pairs and led to histological alterations of ovaries and testes and increased gonadosomatic index. Transcriptional analysis of up to 28 genes belonging to different pathways demonstrated alterations in steroid hormone receptors, steroidogenesis enzymes, and specifically, the circadian rhythm genes, in different organs of adult zebrafish and eleuthero-embryos. Alterations occurred even at environmentally relevant concentrations of 4.5-4.8 ng/L MPA, DDG and the mixture in eleuthero-embryos and at 43-89 ng/L in adult zebrafish. Additionally, the mixtures displayed additive effects in most but not all parameters in adults and eleuthero-embryos, suggesting concentration addition. Our data suggest that MPA and DDG and their mixtures induce multiple transcriptional responses at environmentally relevant concentrations and adverse effects on reproduction and gonad histology at higher levels.

Cross-species toxicogenomic analyses and phenotypic anchoring in response to groundwater low-level pollution

Background

Comparison of toxicogenomic data facilitates the identification of deregulated gene patterns and maximizes health risk prediction in human.

Results

Here, we performed phenotypic anchoring on the effects of acute exposure to low-grade polluted groundwater using mouse and zebrafish. Also, we evaluated two windows of chronic exposure in mouse, starting in utero and at the end of lactation. Bioinformatic analysis of livers microarray data showed that the number of deregulated biofunctions and pathways is higher after acute exposure, compared to the chronic one. It also revealed specific profiles of altered gene expression in all treatments, pointing to stress response/mitochondrial pathways as major players of environmental toxicity. Of note, dysfunction of steroid hormones was also predicted by bioinformatic analysis and verified in both models by traditional approaches, serum estrogens measurement and vitellogenin mRNA determination in mice and zebrafish, respectively.

Conclusions

In our report, phenotypic anchoring in two vertebrate model organisms highlights the toxicity of low-grade pollution, with varying susceptibility based on exposure window. The overlay of zebrafish and mice deregulated pathways, more than single genes, is useful in risk identification from chemicals implicated in the observed effects.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-1067) contains supplementary material, which is available to authorized users.