A computational insight into endocrine disruption by polychlorinated biphenyls via non-covalent interactions with human nuclear receptors

Computational journey to unveil organophosphorothioate pesticides' metabolism: A focus on chlorpyrifos and CYP2C19 mutational landscape

Organophosphorothioates (OPT) are pesticides impacting human, animal and environmental health. They enter the environment worldwide, primarily due to their application as insecticides. OPTs are mainly neurotoxic upon bioactivation and inhibition of brain and serum acetylcholinesterase (AChE). Although OPTs are meant to target insects, they are potentially toxic to many other species (including humans), posing risks to non-target organisms and ecosystems. Certain cytochromes P450 (CYP) promote OPTs bioactivation, forming the corresponding oxon metabolites, while others catalyse their detoxification. Understanding the molecular basis of such a bivalent fate may help to clarify the toxicity of OPTs in living organisms, with far-reaching consequences to understand their impact on living organisms and improve risk assessment, to cite but a few. However, although crucial, the underpinning mechanisms still lay unclear. Here, a validated computational pipeline revealed the molecular reasons underlying the differential metabolism of chlorpyrifos in humans by CYP2C19, a primal route of detoxification, and its bioactivation by CYP2B6. The analysis drew the diverse occupancy of the CYP pocket and orientation to the heme group as a convincing evidence-based explanation for the opposite transformation. Moreover, this study explored the impact of CYP2C19 mutational landscape giving a blueprint to unveil the molecular basis of OPTs metabolism and toxicological implications from an inter-individual perspective. Taken together, the outcome described for the first time to the best of our knowledge a structural rationale for the bioactivation/detoxification of OPTs improving the current understanding of their toxicity from a molecular standpoint.

Polychlorinated biphenyl congeners in water canals and their relationships with water quality parameters: Insights into their risk assessment

Water pollution with pesticides is one of the most important environmental problems. Polychlorinated biphenyls (PCBs) reach water bodies via agricultural discharge. The aim of this study was to determine the contamination of different water bodies with PCB congeners, and detect the correlation between water quality parameters and seasonal distribution of these PCBs. The results indicated that water canals of AlGharbiah showed the highest ranges of temperature, total dissolved solids (TDS) in spring, and dissolved oxygen (DO) in autumn, while AlQaliobiah water bodies witnessed the highest pH and electrical conductivity (EC) ranges in summer. The highest range of a PCB congener was that of PCB44 (7.96-118.29 µg/g) in sediment samples of Giza, followed by its range (18.01-85.44 µgL-1) in surface water of AlQaliobiah. We found a potential cancer risk from dermal contact with all the investigated PCBs. Principal component analysis (PCA) showed positive correlations between most PCBs and each of EC and TDS, and a negative correlation with DO. While the correlation between PCBs and each of temperature and pH varied according to the geographic location of the governorate. In conclusion, the investigated water canals were contaminated with PCBs, which posed a potential cancer risk and deteriorated water quality.

Aquatic toxicity, ecological effects, human exposure pathways and health risk assessment of liquid crystal monomers

Liquid crystal monomers (LCMs), one of the key materials for liquid crystal displays, have been considered as emerging pollutants in recent years. However, the environmental behaviors of LCMs have not yet been well investigated. The toxicity data of 1173 LCMs were calculated by integrated computational simulation methods in this study. It showed that 64.6% LCMs exhibited PBT (persistent, bioaccumulative, and toxic) properties. Based on the results, 1173 LCMs were identified as molecules possessing the highest level of acute toxicity to aquatic organisms. Among which, and a human health risk priority control list about LCMs was generated in this study, among which 435 were classified as requiring priority control LCMs. It was confirmed that LCMs could eventually accumulate in the human body along the aquatic food chain or penetrate the bloodstream through the dermis, thereby causing harm to health by identifying the exposure pathways of LCMs in humans. Additionally, the electronegativity of the side chain group of LCMs is the main factor causing toxicity differences; therefore, the LCMs containing halogens presented significant acute and chronic toxic effects. This study provided a more comprehensive understanding of LCMs for the public and scientific strategies for controlling LCMs.

Environmental endocrine disruptors and pregnane X receptor action: A review

The pregnane X receptor (PXR) is a kind of orphan nuclear receptor activated by a series of ligands. Environmental endocrine disruptors (EEDs) are a wide class of molecules present in the environment that are suspected to have adverse effects on the endocrine system by interfering with the synthesis, transport, degradation, or action of endogenous hormones. Since EEDs may modulate human/rodent PXR, this review aims to summarize EEDs as PXR modulators, including agonists and antagonists. The modular structure of PXR is also described, interestingly, the pharmacology of PXR have been confirmed to vary among different species. Furthermore, PXR play a key role in the regulation of endocrine function. Endocrine disruption of EEDs via PXR and its related pathways are systematically summarized. In brief, this review may provide a way to understand the roles of EEDs in interaction with the nuclear receptors (such as PXR) and the related pathways.

Endocrine-disrupting chemicals and autoimmune diseases

Endocrine-disrupting chemicals (EDCs) widely exist in people's production and life which have great potential to damage human and animal health. Over the past few decades, growing attention has been paid to the impact of EDCs on human health, as well as immune system. So far, researchers have proved that EDCs (such as bisphenol A (BPA), phthalate, tetrachlorodibenzodioxin (TCDD), etc.) affect human immune function and promotes the occurrence and development of autoimmune diseases (ADs). Therefore, in order to better understand how EDCs affect ADs, we summarized the current knowledge about the impact of EDCs on ADs, and elaborated the potential mechanism of the impact of EDCs on ADs in this review.

Comparison of PSA to Moringa Oleifera Seed Protein as Sorbent in QuEChERS: A Response Surface Methodology Optimization for Extraction of Some Endocrine Disrupting Chemicals in Food

This work aimed at optimizing the QuEChERS method with PSA and then comparing it with Moringa Oleifera seed protein as a clean-up sorbent for the extraction of endocrine-disrupting chemicals. The response surface methodology approach was used in the optimization. A design of experiment (DoE) was used to investigate the effect of the sample mass (0.5–3 g), centrifuge speed (3400–4000 rpm) and time (5–20 min), the mass of $NaCl$ and ${\text{MgSO}}_4\left(1-3\hspace{0.17em}\text{g}\right)$ , and solvent extraction volume (5–10 mL). The analysis was done using GC-ECD and GC × GC TOFMS. The PSA method which was later replaced with Moringa Oleifera seed protein presented optimal values of 3 g of sample, 150 mg PSA, 4000 rpm for 6 min centrifuge conditions, including 2 g NaCl and 2 g ${\text{MgSO}}_4\hspace{0.17em}$ extracted in 10 mL methanol, respectively. Moringa Oleifera seed protein gave better selectivity, and the detection limits ranged between 0.16 and 1.77 $\mu {\text{g\hspace{0.17em}kg}}^{-1}$ with RSD values $\le 13.32\%,$ respectively. Moreover, recoveries were between 76.2  $\pm$  0.85% and 105.2  $\pm$  2.24%. Application of the developed method in food samples detected some EDCs. This study has shown that Moringa Oleifera seed protein is a promising alternative to PSA in the clean-up of food-related samples using the QuEChERS approach.

In silico prediction of nuclear receptor binding to polychlorinated dibenzofurans and its implication on endocrine disruption in humans and wildlife

Polychlorinated dibenzofurans (PCDFs) are known to cause endocrine disruption in humans and wildlife but the mechanisms underlying this disruption have not been adequately investigated. In this paper, the susceptibility of the endocrine system to disruption by PCDF congeners via nuclear receptor binding was studied using molecular docking simulation. Findings revealed that some PCDF congeners exhibit high probabilities of binding to androgen receptor in its agonistic and antagonistic conformations. In depth molecular docking analysis of the receptor-ligand complexes formed by PCDFs with androgen receptor in its agonistic and antagonistic conformations showed that, these complexes were stabilized by electrostatic, van der Waals, pi-effect and hydrophobic interactions. It was also observed that PCDF molecules mimic the modes of interaction observed in androgen-testosterone and androgen-bicalutamide complexes, utilizing between 65 and 83% of the amino acid residues used by the co-crystallized ligands for binding. This computational study suggests that some PCDF congeners may act as agonists and antagonists of androgen receptor in humans and wildlife via inapproprate binding to the receptor.