Gene-Environment Interactions in Developmental Neurotoxicity: a Case Study of Synergy between Chlorpyrifos and CHD8 Knockout in Human BrainSpheres.

BACKGROUND: Autism spectrum disorder (ASD) is a major public health concern caused by complex genetic and environmental components. Mechanisms of gene-environment (G×E) interactions and reliable biomarkers associated with ASD are mostly unknown or controversial. Induced pluripotent stem cells (iPSCs) from patients or with clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9 (CRISPR/Cas9)-introduced mutations in candidate ASD genes provide an opportunity to study (G×E) interactions. OBJECTIVES: In this study, we aimed to identify a potential synergy between mutation in the high-risk autism gene encoding chromodomain helicase DNA binding protein 8 (CHD8) and environmental exposure to an organophosphate pesticide (chlorpyrifos; CPF) in an iPSC-derived human three-dimensional (3D) brain model. METHODS: This study employed human iPSC-derived 3D brain organoids (BrainSpheres) carrying a heterozygote CRISPR/Cas9-introduced inactivating mutation in CHD8 and exposed to CPF or its oxon-metabolite (CPO). Neural differentiation, viability, oxidative stress, and neurite outgrowth were assessed, and levels of main neurotransmitters and selected metabolites were validated against human data on ASD metabolic derangements. RESULTS: Expression of CHD8 protein was significantly lower in CHD8 heterozygous knockout (CHD8+/-) BrainSpheres compared with CHD8+/+ ones. Exposure to CPF/CPO treatment further reduced CHD8 protein levels, showing the potential (G×E) interaction synergy. A novel approach for validation of the model was chosen: from the literature, we identified a panel of metabolic biomarkers in patients and assessed them by targeted metabolomics in vitro. A synergistic effect was observed on the cholinergic system, S-adenosylmethionine, S-adenosylhomocysteine, lactic acid, tryptophan, kynurenic acid, and α-hydroxyglutaric acid levels. Neurite outgrowth was perturbed by CPF/CPO exposure. Heterozygous knockout of CHD8 in BrainSpheres led to an imbalance of excitatory/inhibitory neurotransmitters and lower levels of dopamine. DISCUSSION: This study pioneered (G×E) interaction in iPSC-derived organoids. The experimental strategy enables biomonitoring and environmental risk assessment for ASD. Our findings reflected some metabolic perturbations and disruption of neurotransmitter systems involved in ASD. The increased susceptibility of CHD8+/- BrainSpheres to chemical insult establishes a possibly broader role of (G×E) interaction in ASD. https://doi.org/10.1289/EHP8580.

Ligand-independent androgen receptor antagonism caused by the newly developed pesticide pyrifluquinazon (PFQ).

Androgen receptor (AR) is an essential component to activate AR dependent gene transcriptions. Despite wide acceptance of pharmacological controls on transcriptional pathway depending on competitive inhibitions of ligand binding, only a few examples, AR antagonism via ligand-independent mechanisms, have been recognized. Pyrifluquinazon(PFQ), a newly developed pesticide, induced representative AR antagonism against rats in in vivo and in vitro. Intriguingly, this AR antagonism was not based on inhibition of ligand binding. Instead, the evidence suggested that the AR antagonism was induced as a consequence of decline of cellular AR protein level. This study demonstrated that AR N-terminal region could be an essential element for a ligand-independent mechanism underling the AR antagonism by PFQ. Our findings should provide a novel insight into the regulation of AR-mediated transcription.

Place-specific constructs of social capital and their possible associations to health: a Japanese case study.

The story of Roseto, Pennsylvania, USA, is one of the most widely cited studies of the putative influence of community social cohesion on population health. However, few contemporary studies of community-based "social capital" on health have addressed "communities" as unique places with unique histories outside of a Western context. In the present study, we focus on a specific region of Japan (which we call the M-region to preserve anonymity). Using survey data and qualitative interviews, we discuss the historical and contextual origins of the high social capital in the M-region that could account for its relatively good health profile. The analysis of survey data suggested that the residents of M-region have higher norms of reciprocity and participate more in horizontal organizations (including volunteer group, citizen or consumer group, sports group or club, and hobby group), and it also indicated better health status and behaviors in some outcomes among the residents of M-region. Based on qualitative interviews, the origins of social capital in the M-region appeared to be rooted in the strong sense of solidarity fostered by the fact that many of the residents were recruited into the region by the same local employer (a steel manufacturing company). Our study points to the need to ground studies of community-based "social capital" and health on detailed knowledge of the historical context of specific places.

Inhibitory mechanisms of the transcriptional activity of androgen receptor by resveratrol: Implication of DNA binding and acetylation of the receptor.

Androgen receptor (AR) is a ligand-dependent transcription factor and plays a key role in the development of prostate cancer. Resveratrol, a polyphenolic compound, inhibits AR function and reduces the level of prostate-specific antigen (PSA), a notable target gene of AR. Here, we investigated the mechanisms by which resveratrol inhibits AR function. Although the protein levels of AR were decreased by resveratrol treatment for 24h, the decrease could not fully account for the suppression of AR function. The total and the nuclear AR levels were not affected after incubation with 10µM resveratrol for 3h, whereas resveratrol inhibited the binding of AR to the enhancer region of PSA and decreased the acetylation of AR even at this early phase. Inhibition of transcription by resveratrol was weaker in the AR acetylation site mutant than in the wild-type. In later phase (24h) after incubation with resveratrol, the ligand-induced nuclear accumulation of AR was markedly decreased by resveratrol. These data show that resveratrol inhibits DNA binding of AR, presumably by decreasing its level of acetylation and suggest that acetylation of AR is involved in its accumulation in the nucleus.

A yeast bioassay for androgenic and anti-androgenic compounds based on the NH2- and COOH-terminal interaction of androgen receptor.

Androgenic compounds induce an interaction between the NH(2)- and COOH-terminal regions (N-C interaction) of androgen receptor (AR). We describe a rapid yeast bioassay for androgenic and anti-androgenic compounds based on androgen-dependent ß-catenin-enhanced N-C interaction. The bioassay was also effective at detecting compounds that inhibit the N-C interaction in ways that do not involve binding to the ligand-binding domain.

[An evaluation of an area's social capital by public health nurses].

PURPOSE: To clarify how public health nurses evaluate the social capital (SC) of an area and clarify associations with the area's health level. METHOD: Using a five-point scale, we conducted a questionnaire survey of public health nurses (n = 70) in area B of prefecture A with questions about: (1) health behaviour; (2) the residential environment; (3) social relationships; (4) activity and responsiveness; and (5) total health level in different elementary school districts. In the same area, we also conducted a questionnaire survey of the elderly living in the community (n = 17,269) and compared the results with those of the public health nurse survey. Correlation analysis and multiple regression analysis were applied to identify associations between variables in a comparison of the two surveys. RESULTS: Correlations between the two surveys for an SC index were found, for example between (3) social relationships and "locality attachment" (r = .425, P<0.01), (3) social relationships and "meeting friends" (r = .404, P<0.01), and (4) activity and responsiveness and "receiving support" (r = .233, P< 0.05), indicating that public health nurses can determine the kind of SC that an area has. The results of multiple regression analysis, using total health level as a dependent variable and the other four variables as independent variables, showed that an area's SC (indicated by social relationships and activeness and responsiveness) can be evaluated using associations with the area's health level. Experienced public health nurses (n = 24, 11 and above service years) well captured social relationships and evaluated them in relation to health level, whereas young public health nurses (n = 46, 10 and below service years) well captured activity and responsiveness and evaluated them in relation to health level. CONCLUSION: On the basis of the results showing that public health nurses can determine an area's SC in relation to its health level, we could show using social capital theory the importance of having a public health nurse evaluate and diagnose a community's SC.

Resveratrol down-regulates the androgen receptor at the post-translational level in prostate cancer cells.

Androgen receptor (AR) functions as a transcriptional factor for the development and progression of prostate cancer. Resveratrol is known to inhibit the function of AR and to repress AR expression at the transcriptional level. This study focuses on the effects of resveratrol on the AR function and the post-translational AR level. Resveratrol repressed the transcriptional activities of a mutant AR lacking the ligand-binding domain, a constitutive active form of AR, and wild-type AR in a concentration-dependent manner in human prostate cancer PC-3 cells, indicating that resveratrol does not inhibit the transcriptional activity of AR through binding to the ligand-binding domain of AR. Furthermore, the half-life of AR protein was approximately 4 h in resveratrol-treated AR-positive prostate cancer LNCaP cells, compared to approximately 13 h in control cells, as determined by cycloheximide chase. These results indicate that resveratrol down-regulates AR protein through a post-translational mechanism and suggest that the inhibitory effect of resveratrol on AR function is partly attributable to a decrease in the post-translational AR level.