Effects of Prenatal and Neonatal Exposure to Bisphenol A on the Development of the Central Nervous System

Systematic Analysis of Protein-Protein and Gene-Environment Interactions to Decipher the Cognitive Mechanisms of Autism Spectrum Disorder

Autism spectrum disorder (ASD), a heterogeneous neurodevelopmental disorder resulting from both genetic and environmental risk factors, is manifested by deficits in cognitive function. Elucidating the cognitive disorder-relevant biological mechanisms may open up promising therapeutic approaches. In this work, we mined ASD cognitive phenotype proteins to construct and analyze protein-protein and gene-environment interaction networks. Incorporating the protein-protein interaction (PPI), human cognition proteins, and connections of autism-cognition proteins enabled us to generate an autism-cognition network (ACN). With the topological analysis of ACN, important proteins, highly clustered modules, and 3-node motifs were identified. Moreover, the impact of environmental exposures in cognitive impairment was investigated through chemicals that target the cognition-related proteins. Functional enrichment analysis of the ACN-associated modules and chemical targets revealed biological processes involved in the cognitive deficits of ASD. Among the 17 identified hub-bottlenecks in the ACN, PSD-95 was recognized as an important protein through analyzing the module and motif interactions. PSD-95 and its interacting partners constructed a cognitive-specific module. This hub-bottleneck interacted with the 89 cognition-related 3-node motifs. The identification of gene-environment interactions indicated that most of the cognitive-related proteins interact with bisphenol A (BPA) and valproic acid (VPA). Moreover, we detected significant expression changes of 56 cognitive-specific genes using four ASD microarray datasets in the GEO database, including GSE28521, GSE26415, GSE18123 and GSE29691. Our outcomes suggest future endeavors for dissecting the PSD-95 function in ASD and evaluating the various environmental conditions to discover possible mechanisms of the different levels of cognitive impairment.

Differential effects of bisphenol A toxicity on oyster (Crassostrea angulata) gonads as revealed by label-free quantitative proteomics

Bisphenol A (BPA) is widely used in industry, and is released in large amounts into the environment. BPA is a teratogen and an estrogen receptor agonist and negatively affects reproduction, particularly in aquatic animals, which is of concern for the aquaculture industry. Although there is a large body of literature on the mechanisms that underlie BPA disruption and the effects of different toxicities on invertebrate reproduction, many of the mechanisms involved in invertebrate responses to BPA remain unknown. In this study, we investigated the effects of BPA on the reproduction of female and male oysters (Crassostrea angulata), and measured BPA bioaccumulation, the gonad-somatic index (GSI), and gonadal protein profiles in oysters exposed to BPA. Compared to controls, approximately 160-times more BPA accumulated in the gonads of male and female oysters after exposure to 2 mg L^-1 BPA for 16 days. Gonadal development was negatively affected in males, but was accelerated in females when exposed to BPA, based on GSI analysis and a visual inspection of histological sections of the gonads. BPA exposure induced the differential expression of many important proteins such as vitellogenin, periostin, phosphoglucomutase, collagen alpha-1(XII) chain, and zinc transporter 9, which are involved in energy metabolism, oxidative stress, gene transcription regulation, the vitellogenin interaction network, and zinc transportation. A functional analysis of these proteins indicated that BPA has different effects on gonadal development in male and female oysters.

1H-NMR-based metabolomic studies of bisphenol A in zebrafish (Danio rerio)

Proton nuclear magnetic resonance (¹H-NMR) spectroscopy was used to study the response of zebrafish (Danio rerio) to increasing concentrations of bisphenol A (4,4'-(propane-2,2-diyl)diphenol, BPA). Orthogonal partial least squares discriminant analysis (OPLS-DA) was applied to detect aberrant metabolomic profiles after 72 h of BPA exposure at all levels tested (0.01, 0.1, and 1.0 mg/L). The OPLS-DA score plots showed that BPA exposure caused significant alterations in the metabolome. The metabolomic changes in response to BPA exposure generally exhibited nonlinear patterns, with the exception of reduced levels of several metabolites, including glutamine, inosine, lactate, and succinate. As the level of BPA exposure increased, individual metabolite patterns indicated that the zebrafish metabolome was subjected to severe oxidative stress. Interestingly, ATP levels increased significantly at all levels of BPA exposure. In the present study, we demonstrated the applicability of ¹H-NMR-based metabolomics to identify the discrete nature of metabolic changes.

Distribution of bisphenol-A, triclosan and n-nonylphenol in human adipose tissue, liver and brain

In this study, an analytical method was optimized for the determination of bisphenol-A (BPA), triclosan (TCS) and 4-n-nonylphenol (4n-NP), environmental contaminants with potential endocrine disruptive activities, in human tissues. The method consisted of a liquid extraction step, derivatization with pentafluorobenzoylchloride followed by a clean-up on acidified silica and detection with gas chromatography coupled with mass spectrometry (GC-ECNI/MS). Recoveries ranged between 92% and 102% with a precision below 5%. Limits of quantification ranged between 0.3-0.4 ng g(-1), 0.045-0.06 ng g(-1) and 0.003-0.004 ng g(-1) for BPA, TCS and 4n-NP in different tissues, respectively. The method was applied for the determination of BPA, TCS and 4n-NP in paired adipose tissue, liver and brain samples from 11 individuals. BPA could be detected in almost all tissues, with the highest concentrations found in adipose tissue (mean 3.78 ng g(-1)), followed by liver (1.48 ng g(-1)) and brain (0.91 ng g(-1)). TCS showed the highest concentrations in liver (3.14 ng g(-1)), followed by adipose tissue (0.61 ng g(-1)), while it could be detected in only one brain sample. Levels of 4n-NP were much lower, mostly undetected, and therefore 4n-NP is considered of minor importance for human exposure. Despite the measurable concentrations in adipose tissue, these compounds seem to have a low bioaccumulation potential. The reported concentrations of free BPA in the various tissues are slight disagreement with pharmacokinetic models in humans and rats and therefore the possibility of external contamination with BPA during sample collection/storage cannot be ruled out.