Identification of metabolic pathways related to the bisphenol A-induced adipogenesis in differentiated murine adipocytes by using RNA-sequencing

Emerging regulatory roles of noncoding RNAs induced by bisphenol a (BPA) and its alternatives in human diseases

Bisphenols (BPs), including BPA, BPF, BPS, and BPAF, are synthetic phenolic organic compounds and endocrine-disrupting chemicals. These organics have been broadly utilized to produce epoxy resins, polycarbonate plastics, and other products. Mounting evidence has shown that BPs, especially BPA, may enter into the human body and participate in the development of human diseases mediated by nuclear hormone receptors. Moreover, BPA may negatively affect human health at the epigenetic level through processes such as DNA methylation and histone acetylation. Recent studies have demonstrated that, as part of epigenetics, noncoding RNAs (ncRNAs), including microRNAs (miRNAs), long noncoding RNAs (lncRNAs), circular RNAs (circRNAs), and small nucleolar RNAs (snoRNAs), have vital impacts on BP-related diseases, such as reproductive system diseases, nervous system diseases, digestive system diseases, endocrine system diseases, and other diseases. Moreover, based on the bioinformatic analysis, changes in ncRNAs may be relevant to normal activities and functions and BP-induced diseases. Thus, we conducted a meta-analysis to identify more promising ncRNAs as biomarkers and therapeutic targets for BP exposure and relevant human diseases. In this review, we summarize the regulatory functions of ncRNAs induced by BPs in human diseases and latent molecular mechanisms, as well as identify prospective biomarkers and therapeutic targets for BP exposure and upper diseases.

Confirmation of the steroid hormone receptor-mediated endocrine disrupting potential of fenvalerate following the Organization for Economic Cooperation and Development test guidelines, and its estrogen receptor α-dependent effects on lipid accumulation

In this study, we focused on confirming the steroid hormone receptor-mediated endocrine-disrupting potential of the pyrethroid insecticide fenvalerate and unraveling the underlying mechanisms. Therefore, we assessed estrogen receptor-α (ERα)- and androgen receptor (AR)-mediated responses in vitro using a hormone response element-dependent transcription activation assay with a luciferase reporter following the Organization for Economic Cooperation and Development (OECD) test guidelines. We observed that fenvalerate acted as estrogen by inducing the translocation of cytosolic ERα to the nucleus via ERα dimerization, whereas it exhibited no AR-mediated androgen response element-dependent luciferase activity. Furthermore, we confirmed that fenvalerate-induced activation of ERα caused lipid accumulation, promoted in a fenvalerate-dependent manner in 3 T3-L1 adipocytes. Moreover, fenvalerate-induced lipid accumulation was inhibited in the presence of an ERα-selective antagonist, whereas it remained unaffected in the presence of a glucocorticoid receptor (GR)-specific inhibitor. In addition, fenvalerate was found to stimulate the expression of transcription factors that promote lipid accumulation in 3 T1-L1 adipocytes, and co-treatment with an ERα-selective antagonist suppressed adipogenic/ lipogenic transcription factors at both mRNA and protein levels. These findings suggest that fenvalerate exposure may lead to lipid accumulation by interfering with ERα activation-dependent processes, thus causing an ERα-mediated endocrine-disrupting effect.

The obesogen bisphenol A promotes adipogenesis in canine adipose-derived stem cells: Potential implication in dog obesity

The growing number of companion dogs has contributed to a rapidly growing market for pet products, including dog toys. However, little is known about the hazardous substances released from dog toys. This study aims to examine the potential presence of obesogens, a subset of endocrine-disrupting chemicals (EDCs) that are widely utilized as raw materials in the manufacture of dog toy components, and their effects on dog health. To achieve this, we adapted and employed a migration method typically used for children's products to simulate obesogen exposure in dogs through sucking or chewing toys. We demonstrated that out of various obesogens, bisphenol A (BPA) was released from dog toys into synthetic saliva, whereas phthalates and azo dyes were not detected in any of the leachates. Additionally, we found that BPA induced adipogenic differentiation in canine adipose-derived stem cells (cADSCs). Our RNA sequencing experiments revealed that BPA alters the adipogenesis-related gene signature in cADSCs by elevating the expression levels of ADIPOQ, PLIN1, PCK1, CIDEC, and FABP4. The associated transcriptional changes are involved in the peroxisome proliferator-activated receptor (PPAR) signaling pathway, which may contribute to the promotion of adipogenesis by BPA. Our findings suggest that companion dogs are at risk of BPA exposure, which may contribute to obesity in dogs. Therefore, the implementation of precautionary measures is crucial.

Stimulation of estrogen receptor-alpha by hydroxyanilide fungicide, fenhexamid promotes lipid accumulation in 3 T3-L1 adipocyte

Fenhexamid are fungicides that act against plant pathogens by inhibiting sterol biosynthesis. Nonetheless, it can trigger endocrine disruption and promote breast cancer cell growth. In a recent study, we investigated the mechanism underlying the lipid accumulation induced by fenhexamid hydroxyanilide fungicides in 3 T3-L1 adipocytes. To examine the estrogen receptor alpha (ERα)-agonistic effect, ER transactivation assay using the ERα-HeLa-9903 cell line was applied, and fenhexamid-induced ERα agonist effect was confirmed. Further confirmation that ERα-dependent lipid accumulation occurred was provided by treating 3 T3-L1 adipocytes with Methyl-piperidino-pyrazole hydrate (MPP), an ERα-selective antagonist. Fenhexamid mimicked the actions of ERα agonists and impacted lipid metabolism, and its mechanism involves upregulation of the expression of transcription factors that facilitate adipogenesis and lipogenesis. Additionally, it stimulated the expression of peroxisome proliferator-activated receptor (PPARγ), CCAAT/enhancer-binding protein α (C/EBPα), fatty acid synthase (FAS), and sterol regulatory element-binding protein 1 (SREBP1) and significantly elevated the expression of fatty acid-binding protein 4 (FABP4). In contrast, in combination with an ERα-selective antagonist, fenhexamid suppressed the expression of adipogenic/lipogenic transcription factors. These results suggest that fenhexamid affects the endocrine system and leads to lipid accumulation by interfering with processes influenced by ERα activation.

Comprehensive assessment of the estrogenic activity of resin composites

Resin-based dental composites have been developed to restore decayed teeth or modify tooth color due to their excellent physical and chemical properties. Such composites may have intrinsic toxicity due to components released into the mouth during the early stage of polymerization, and afterward as a result of erosion or material decomposition. In addition, resin-based dental composites have potential environmental pollutant by elution of monomers and degradation. Since certain monomers of resin matrices are synthesized from bisphenol A (BPA), which acts as an estrogenic endocrine disruptor, these resin matrices may have estrogenic activity. Therefore, the estrogenic endocrine-disrupting activity of various dental composites should be evaluated. In this study, we evaluated the estrogenic endocrine-disrupting activity of 10 resin composites by using a BRET-based estrogen receptor (ER)α and ERβ dimerization assays and ER transactivation assay. BPA, BisDMA, BisGMA, BisEMA, TEGDMA, HMBP, and DMPA mediated ERα dimerization, and BPA, BisDMA, and DMPA also mediated ERβ dimerization. Except for UDMA and CQ, all the compounds were identified as estrogen agonists or antagonists. In-depth information for the safe use of dental composites was acquired, and it was confirmed how the component of dental composites acts in the ER signaling pathway. Further studies on the low-dose and long-term release of these compounds are needed to ensure the safe use of these resin-based dental composites.

Exposure to environmental pollutant bisphenol A causes oxidative damage and lipid accumulation in Zebrafish larvae: Protective role of WL15 peptide derived from cysteine and glycine-rich protein 2

Humans are exposed to obesity causing Bisphenol A in various ways, especially through diet and food containers. Bioactive peptides are already reported to have antioxidant, antidiabetic, and antiobesity properties, which can mimic the role of mediators involved in obesity prevention. The protective effect of a short molecule or peptide, WL15 from cysteine and glycine-rich protein 2 of a teleost of aquatic resource on Bisphenol A (BPA)-induced lipid accumulation in zebrafish larvae was investigated. BPA exposure disrupted the antioxidant enzymes, apoptosis, and nitric oxide and led to changes in biochemical markers including alkaline phosphatase, lactate dehydrogenase, lipid peroxidation, glutathione S-transferases, glutathione peroxidase, and reduced glutathione. However, WL15 inhibited the overproduction of oxidative stress, which correlates with its lipid-lowering potential. BPA-induced lipid accumulation in zebrafish showed an increase in triglyceride, cholesterol, and glucose level; simultaneously, WL15 treatment significantly reduced such accumulation in zebrafish. Evidenced by Oil red O staining and Nile red assay, WL15 inhibited lipid accumulation. At the same time, WL15 at 50 µM increases 2-(N-[7-nitrobenz-2-oxa-1,3-diazol-4-yl]amino)-2-deoxy-d-glucose (2NBDG) glucose uptake in zebrafish. In addition, gene expression studies in zebrafish larvae demonstrated that the WL15 peptide could play a crucial role in preventing lipid accumulation by downregulating the expression of lipogenesis-specific genes. These results revealed an interesting and novel property of WL15, suggesting its potential application in preventing lipid accumulation through the hypolipidemic and antioxidant properties.

Natural Products in Mitigation of Bisphenol A Toxicity: Future Therapeutic Use

Bisphenol A (BPA) is a ubiquitous environmental toxin with deleterious endocrine-disrupting effects. It is widely used in producing epoxy resins, polycarbonate plastics, and polyvinyl chloride plastics. Human beings are regularly exposed to BPA through inhalation, ingestion, and topical absorption routes. The prevalence of BPA exposure has considerably increased over the past decades. Previous research studies have found a plethora of evidence of BPA’s harmful effects. Interestingly, even at a lower concentration, this industrial product was found to be harmful at cellular and tissue levels, affecting various body functions. A noble and possible treatment could be made plausible by using natural products (NPs). In this review, we highlight existing experimental evidence of NPs against BPA exposure-induced adverse effects, which involve the body’s reproductive, neurological, hepatic, renal, cardiovascular, and endocrine systems. The review also focuses on the targeted signaling pathways of NPs involved in BPA-induced toxicity. Although potential molecular mechanisms underlying BPA-induced toxicity have been investigated, there is currently no specific targeted treatment for BPA-induced toxicity. Hence, natural products could be considered for future therapeutic use against adverse and harmful effects of BPA exposure.

Anti-Obesity and Anti-Adipogenic Effects of Administration of Arginyl-Fructose-Enriched Jeju Barley (Hordeum vulgare L.) Extract in C57BL/6 Mice and in 3T3-L1 Preadipocytes Models

In our previous study, we reported that arginyl-fructose (AF), one of the Amadori rearrangement compounds (ARCs) produced by the heat processing of Korean ginseng can reduce carbohydrate absorption by inhibiting intestinal carbohydrate hydrolyzing enzymes in both in vitro and in vivo animal models. This reduced absorption of carbohydrate might be helpful to control body weight gain due to excessive carbohydrate consumption and support induced calorie restriction. However, the weight management effect, except for the effect due to anti-hyperglycemic action, along with the potential mechanism of action have not yet been determined. Therefore, the efforts of this study are to investigate and understand the possible weight management effect and mechanism action of AF-enriched barley extracts (BEE). More specifically, the effect of BEE on lipid accumulation and adipogenic gene expression, body weight gain, body weight, plasma lipids, body fat mass, and lipid deposition were evaluated using C57BL/6 mice and 3T3-L1 preadipocytes models. The formation of lipid droplets in the 3T3-L1 treated with BEE (500 and 750 µg/mL) was significantly blocked (p < 0.05 and p < 0.01, respectively). Male C57BL/6 mice were fed a high-fat diet (30% fat) for 8 weeks with BEE (0.3 g/kg-body weight). Compared to the high fat diet control (HFD) group, the cells treated with BEE significantly decreased in intracellular lipid accumulation with concomitant decreases in the expression of key transcription factors, peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer-binding protein alpha (CEBP/α), the mRNA expression of downstream lipogenic target genes such as fatty acid binding protein 4 (FABP4), fatty acid synthase (FAS), and sterol regulatory element-binding protein 1c (SREBP-1c). Supplementation of BEE effectively lowered the body weight gain, visceral fat accumulation, and plasma lipid concentrations. Compared to the HFD group, BEE significantly suppressed body weight gain (16.06 ± 2.44 g vs. 9.40 ± 1.39 g, p < 0.01) and increased serum adiponectin levels, significantly, 1.6-folder higher than the control group. These results indicate that AF-enriched barley extracts may prevent diet-induced weight gain and the anti-obesity effect is mediated in part by inhibiting adipogenesis and increasing adiponectin level.

Transcriptome Changes and Potential Immunotoxicity Analysis in RAW264.7 Macrophages Caused by Bisphenol F

As a viable substitute for bisphenol A (BPA), BPF has been widely used in the plastic industry and daily consumer goods, resulting in its detection in humans at a comparable concentration. Evidence reveals that BPF and BPA may have similar toxic effects due to their similar structures. However, there is less information about BPF and its latent implications on the immune system, which is associated with many disorders. In this study, the in vitro toxicity of BPF on RAW264.7 macrophages was explored. The cells were treated with different concentrations of BPF (5, 10, 20, 50, 100, and 200 μM), the cell viability and apoptosis were detected, the gene expression profile was analyzed by whole-transcriptome sequencing, and the mRNA levels were detected by qRT-PCR. The results showed a high concentration of BPF could significantly reduce the survival rate of RAW264.7 macrophages. Although the medium concentration (20–50 μM) of BPF seemed to have no impact on the cell activity of macrophages, it caused the occurrence of apoptosis. The results of differential transcription showed that compared with the control group, 121 genes were upregulated and 82 genes were downregulated in the BPF group. The significantly changed gene functions were mainly concentrated in cell cycle, phagosome, lysosome, and antigen processing and presentation. These findings provide valuable information for correctly understanding the immunotoxicity risk of BPF and may help to improve the hazard identification of bisphenol compounds.

The hazardous threat of Bisphenol A: Toxicity, detection and remediation

Bisphenol A (or BPA) is a toxic endocrine disrupting chemical that is released into the environment through modern manufacturing practices. BPA can disrupt the production, function and activity of endogenous hormones causing irregularity in the hypothalamus-pituitary-gonadal glands and also the pituitary-adrenal function. BPA has immuno-suppression activity and can downregulate T cells and antioxidant genes. The genotoxicity and cytotoxicity of BPA is paramount and therefore, there is an immediate need to properly detect and remediate its influence. In this review, we discuss the toxic effects of BPA on different metabolic systems in the human body, followed by its mechanism of action. Various novel detection techniques (LC-MS, GC-MS, capillary electrophoresis, immunoassay and sensors) involving a pretreatment step (liquid-liquid microextraction and molecularly imprinted solid-phase extraction) have also been detailed. Mechanisms of various remediation strategies, including biodegradation using native enzymes, membrane separation processes, photocatalytic oxidation, use of nanosorbents and thermal degradation has been detailed. An overview of the global regulations pertaining to BPA has been presented. More investigations are required on the efficiency of integrated remediation technologies rather than standalone methods for BPA removal. The effect of processing operations on BPA in food matrices is also warranted to restrict its transport into food products.

Organophosphorus pesticides exert estrogen receptor agonistic effect determined using Organization for Economic Cooperation and Development PBTG455, and induce estrogen receptor-dependent adipogenesis of 3T3-L1 adipocytes

Various chemicals containing pesticides can induce adipogenesis and cause obesity. Organophosphorus pesticides have been used for pest control. Here, we investigated the estrogen receptor (ER)-dependent adipogenesis-inducing effect of representative organophosphorus pesticides (OPs), diazinon, phoxim, terbufos and tolclofos-methyl in 3T3-L1 adipocytes. Four OPs exhibited ER agonistic effect, determined using the OECD Performance Based Test Guideline No. 455; in vitro ER stably transfected transactivation assay using ERα-HeLa-9903 cell line, through binding affinity to ERα. Additionally, they increased lipid droplet accumulation in a dose-dependent manner, which was suppressed by ICI182,780, a well-known ER antagonist. Four OPs treatment induced peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer-binding protein alpha (C/EBPα), and perilipin expression. Furthermore, PPARγ, C/EBPα and perilipin expression was inhibited by co-treatment with ICI182,780. The increased mRNA expression of lipoprotein lipase and fatty acid synthase by four OPs was suppressed by co-treatment with ICI182,780. These results indicated that diazinon, phoxim, terbufos, and tolclofos-methyl might have adipogenesis-inducing effect mediated by interacting with ER.

Transcriptomic responses to pollution in natural riverine environment in Rita rita

Aquatic pollution is one of the most common threats to the ecological health of aquatic ecosystems and its biota. Fish as lower vertebrates are excellent model to study the impact and responses of aquatic pollution. In fish, gill is the main organ indicator of whole animal health as it comes in contact with the surrounding water and absorbs many pollutants and contaminants; therefore, investigations on alterations in fish gill at transcriptome level could provide newer insights to the stress response mechanism(s) and pathways. For comprehensive evaluation of the impacts of pollutants (joint toxicity) prevalent in the riverine environment, comparative transcriptome analysis, by Next Generation Sequencing under Illumina HiSeq 2500 platform, was carried out in gill tissues of Rita rita collected from two stretches of river Ganga (Kanpur and Farakka) and results were validated by RT-qPCR. Out of 154,077 unigenes (Accession SRR548008), a total of 2024 differentially expressed genes (DEGs) including 942 up-regulated and 1082 down-regulated genes were identified by DESeq program. Further, Gene Ontology (GO) of DEGs showed that ribosomal large subunit biogenesis, mitochondrial ribosome and box H/ACA SnoRNA binding categories are highly affected by pollution. Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis showed the involvement of the DEGs in energy metabolism, translational and transcriptional machinery, protein folding and degradation suggesting that these signalling pathways are highly affected by aquatic pollution. Among the DEGs, up-regulation of cytochrome c oxidase subunit (cox) 7a2 (69.47 fold), hsp70 subunit 14 (hsp70-14, 5.27 fold), muscle related coiled-coil protein (MURC, 21.55 fold), lysozyme G (40.14 fold), cox17 (29.36 fold) were the conspicuous ones which showed similar trends in expression when analysed by RT-qPCR. Based on fold change, perturbation values, correlation analysis by PCA and RT-qPCR validation, up-regulation of cox7a2, MURC and hsp70-14 appeared to be the most promising biomarker responses and could be useful in the evaluation of gill health and possibly be extended towards aquatic ecosystem health assessment.

Bioaccumulation investigation of bisphenol A in HepG2 cells and zebrafishes enabled by cobalt magnetic polystyrene microsphere derived carbon based magnetic solid-phase extraction

A magnetic solid-phase extraction (MSPE) technique coupled with high performance liquid chromatography (HPLC) was developed and used for bioaccumulation investigation of bisphenol A (BPA) in HepG2 cells and zebrafishes. Cobalt magnetic polystyrene microsphere derived carbon (C-Co@PST) as an adsorbent was prepared by in situ polymerization reaction and further annealing treatment. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy and X-ray diffraction were employed to confirm successful synthesis of C-Co@PST. A series of extraction parameters including the amount of the sorbent, the type of elute, extraction time and elution time were investigated to achieve high extraction efficiency. C-Co@PST based MSPE combined with HPLC was successfully established for bioaccumulation research of BPA in living creatures. It was found that the bioconcentration values of BPA in HepG2 cells underwent an increase, then a decrease, and finally reached an equilibrium level of 11.60 μg kg-1 at 8 h. The concentration of BPA in zebrafishes increased ranging from 6.05 μg kg-1 to 31.84 μg kg-1 over a culture time from 1 h to 12 h. Furthermore, linear and exponential models were employed to analyse the bioconcentration variation of BPA in organisms over the exposure time. Mathematical models have been developed to predict the transfer characteristics of BPA.

The adverse health effects of bisphenol A and related toxicity mechanisms

Bisphenol A (BPA) is an industrial component commonly used in synthesis of polycarbonate plastics, epoxy resin and other polymer materials. Due to its mass productions and widespread applications, the presence of BPA is ubiquitous in the environment. BPA can enter the body via different ways such as digestive tract, respiratory tract and dermal tract. As an endocrine disruptor, BPA has estrogen-like and anti-androgen effects causing damages to different tissues and organs, including reproductive system, immune system and neuroendocrine system, etc. Recently, it has been shown that BPA could induce carcinogenesis and mutagenesis in animal models. Here, the underlying mechanisms of BPA-induced multi-organ toxicity were well summarized, involving the receptor pathways, disruption of neuroendocrine system, inhibition of enzymes, modulation of immune and inflammatory responses, as well as genotoxic and epigenetic mechanisms. The aim of this review is to compile the available current research data regarding BPA and provide an overview of the current status of BPA exposure and relevant health effects covering reproductive, developmental, metabolic, immuno, respiratory, hepatic and renal toxicity and carcinogenesis of BPA. This review provides comprehensive data of BPA toxicity on human health and related mechanisms. We also identify any missing data which should be addressed by further studies.