A Mixture of Endocrine Disrupting Chemicals Associated with Lower Birth Weight in Children Induces Adipogenesis and DNA Methylation Changes in Human Mesenchymal Stem Cells

Effects of Environmental Enrichment on Exposure to Human-Relevant Mixtures of Endocrine Disrupting Chemicals in Zebrafish

Fish models used for chemical exposure in toxicological studies are normally kept in barren tanks without any structural environmental enrichment. Here, we tested the combined effects of environmental enrichment and exposure to two mixtures of endocrine disrupting chemicals (EDCs) in zebrafish. Firstly, we assessed whether developmental exposure to an EDC mixture (MIX G1) combined with rearing the fish in an enriched environment influenced behaviour later in life. This was evaluated using locomotion tracking one month after exposure, showing a significant interaction effect between enrichment and the MIX G1 exposure on the measured locomotion parameters. After three months, we assessed behaviour using custom-made behaviour tanks, and found that enrichment influenced swimming activity. Control fish from the enriched environment were more active than control fish from the barren environment. Secondly, we exposed adult zebrafish to a separate EDC mixture (MIX G0) after rearing them in a barren or enriched environment. Behaviour and hepatic mRNA expression for thyroid-related genes were assessed. There was a significant interaction effect between exposure and enrichment on swimming activity and an effect of environment on latency to approach the group of conspecifics, where enriched fish took more time to approach the group, possibly indicating that they were less anxious. Hepatic gene expression of a thyroid-related gene (thrb) was significantly affected by EDC exposure, while enrichment had no discernible impact on the expression of the measured genes. In conclusion, environmental enrichment is important to consider when studying the effects of EDCs in fish.

Prenatal exposures to mixtures of endocrine disrupting chemicals and sex-specific associations with children's BMI and overweight at 5.5 years of age in the SELMA study

BACKGROUND

Prenatal exposure to mixtures of endocrine disrupting chemicals (EDC) has the potential to disrupt human metabolism. Prenatal periods are especially sensitive as many developmental processes are regulated by hormones. Prenatal exposure to EDCs has inconsistently been associated with children's body mass index (BMI) and obesity. The objective of this study was to investigate if prenatal exposure to a mixture of EDCs was associated with children's BMI and overweight (ISO-BMI ≥ 25) at 5.5 years of age, and if there were sex-specific effects.

METHODS

A total of 1,105 mother-child pairs with complete data on prenatal EDCs concentrations (e.g., phthalates, non-phthalate plasticizers, phenols, PAH, pesticides, PFAS, organochlorine pesticides, and PCBs), children's measured height and weight, and selected covariates in the Swedish Environmental Longitudinal, Mother and child, Asthma and allergy (SELMA) study were included in this analysis. The mixture effect of EDCs with children's BMI and overweight was assessed using WQS regression with 100 repeated holdouts. A positively associated WQS index with higher BMI and odds of overweight was derived. Models with interaction term and stratified weights by sex was applied in order to evaluate sex-specific associations.

RESULTS

A significant WQS*sex interaction term was identified and associations for boys and girls were in opposite directions. Higher prenatal exposure to a mixture of EDCs was associated with lower BMI (Mean β = -0.19, 95%CI: -0.40, 0.01) and lower odds of overweight (Mean OR = 0.72, 95%CI: 0.48, 1.04) among girls with borderline significance. However, the association among boys did not reach statistical significance. Among girls, the possible chemicals of concern were MEP, 2-OHPH, BPF, BPS, DPP and PFNA.

CONCLUSION

Prenatal exposure to a mixture of EDCs was associated with lower BMI and overweight among girls, and non-significant associations among boys. Chemicals of concern for girls included phthalates, non-phthalate plasticizers, bisphenols, PAHs, and PFAS.

Enhancers of mesenchymal stem cell stemness and therapeutic potency

Mesenchymal stem cells (MSCs) are multipotent stromal cells that can differentiate into a range of cell types, including osteoblasts, chondrocytes, myocytes, and adipocytes. Multiple preclinical investigations and clinical trials employed enhanced MSCs-dependent therapies in treatment of inflammatory and degenerative diseases. They have demonstrated considerable and prospective therapeutic potentials even though the large-scale use remains a problem. Several strategies have been used to improve the therapeutic potency of MSCs in cellular therapy. Treatment of MSCs utilizing pharmaceutical compounds, cytokines, growth factors, hormones, and vitamins have shown potential outcomes in boosting MSCs' stemness. In this study, we reviewed the current advances in enhancing techniques that attempt to promote MSCs' therapeutic effectiveness in cellular therapy and stemness in vivo with potential mechanisms and applications.

An experimental evaluation of the efficacy of perinatal sulforaphane supplementation to decrease the incidence and severity of vinclozolin-induced hypospadias in the mouse model

Determining the mechanisms of toxicity induced by pollutants has long been a research priority in lieu of considering the mechanisms of resilience that prevent deleterious impacts. Protective mechanisms in many taxa can be therapeutically targeted to enhance resilience to synthetic toxicants. For example, the environmental sensor, Nuclear factor (erythroid-derived 2)-like 2 (Nfe2l2 or Nrf2), a transcription factor, facilitates transcription of many protective genes. Hypospadias is a common malformation of the penis. The risk of being born with hypospadias increases with pollutant exposure. We use vinclozolin-induced hypospadias in the mouse as a model to test the hypothesis that pollutant-induced birth defects can be prevented and reduced in severity by augmenting natural mechanisms of resilience. Pregnant mice were exposed to the demasculinizing toxicant, vinclozolin, in combination with increasing doses of the NRF2 activator, sulforaphane. The sulforaphane dose that most effectively increased masculinization (anogenital distance) was identified and used to test the hypothesis that sulforaphane reduces the hypospadias-inducing potency of vinclozolin. Finally, a Nrf2 knockout study was conducted to test whether NRF2 was required for the sulforaphane-induced rescue effects. Sulforaphane supplementation to vinclozolin exposed embryos increased anogenital distance in a nonlinear fashion typical of Nrf2 activators. The most effective dose of sulforaphane (45 mg/kg) reduced the occurrence and severity of vinclozolin-induced hypospadias and corrected penis morphogenesis. The sulforaphane-induced rescue effect was dependent on the presence of Nrf2. Nrf2 plays a critical role in protecting the fetus from vinclozolin and reduces the incidence and severity of hypospadias, the most common birth defect in boys in many countries. This work lays a foundation for developing prenatal supplements that will protect the fetus from pollutant-induced hypospadias. Studying the protective mechanisms that drive resilience to toxicants will facilitate innovation of protective therapies.