Choline, not folate, can attenuate the teratogenic effects ofdibutyl phthalate (DBP) during early chick embryo development

Prenatal air pollution and children's autism traits score: Examination of joint associations with maternal intake of vitamin D, methyl donors, and polyunsaturated fatty acids using mixture methods

Background

Maternal nutrient intake may moderate associations between environmental exposures and children's neurodevelopmental outcomes, but few studies have assessed joint effects. We aimed to evaluate whether prenatal nutrient intake influences the association between air pollutants and autism-related trait scores.

Methods

We included 126 participants from the EARLI (Early Autism Risk Longitudinal Investigation, 2009-2012) cohort, which followed US pregnant mothers who previously had a child with autism. Bayesian kernel machine regression and traditional regression models were used to examine joint associations of prenatal nutrient intake (vitamins D, B12, and B6; folate, choline, and betaine; and total omega 3 and 6 polyunsaturated fatty acids, reported via food frequency questionnaire), air pollutant exposure (particulate matter <2.5 μm [PM2.5], nitrogen dioxide [NO2], and ozone [O3], estimated at the address level), and children's autism-related traits (measured by the Social Responsiveness Scale [SRS] at 36 months).

Results

Most participants had nutrient intakes and air pollutant exposures that met US standards. Bayesian kernel machine regression mixture models and traditional regression models provided little evidence of individual or joint associations of nutrients and air pollutants with SRS scores or of an association between the overall mixture and SRS scores.

Conclusion

In this cohort with a high familial likelihood of autism, we did not observe evidence of joint associations between air pollution exposures and nutrient intake with autism-related traits. Future work should examine the use of these methods in larger, more diverse samples, as our results may have been influenced by familial liability and/or relatively high nutrient intakes and low air pollutant exposures.

Dibutyl phthalate-induced oxidative stress and apoptosis in swine testis cells and therapy of naringenin via PTEN/PI3K/AKT signaling pathway

Dibutyl phthalate (DBP) is a phthalic acid ester (PAE) that has posed a health hazard to the organisms. Naringenin (NRG) is a flavanone compound that has shown protection against several environmental chemicals through suppression of oxidative stress and activation of phosphatidylinositol 3-kinase/threonine kinase (PI3K/AKT) signaling pathway. Herein, swine testis (ST) cells were treated with 1.8 μM of DBP or/and 25.39 nM of NRG for 24 h, we described the discovery path of NRG inhibition on apoptosis in DBP-exposed ST cells through targeting phosphatase and tensin homologue deleted on chromosome 10 (PTEN). We first found that the anti-apoptosis effect of NRG is dependent on mitochondrial pathway through flow cytometry and related gene/protein expression, and then we detected PI3K/AKT pathway-related gene/protein expression, and established a computational docking assay between NRG and PTEN. We found that NRG specifically binds to three basic residues (His93, Lys125, Lys128) of P loop in PTEN, as well as phosphatase domains (Asp92, His93, Cys124, Lys125, Ala126, Lys128, and Arg130) in active dephosphorylation pockets, thereby reducing PTEN level and activating PI3K/AKT signaling pathway, and further inhibiting oxidative stress and mitochondrial pathway apoptosis. Taken together, our results push forward that NRG deserves further attention as a potential antagonistic therapy against DBP through targeting PTEN to inhibit oxidative stress and activate PI3K/AKT signaling pathway.

Prenatal Diet as a Modifier of Environmental Risk Factors for Autism and Related Neurodevelopmental Outcomes

PURPOSE OF REVIEW

Environmental chemicals and toxins have been associated with increased risk of impaired neurodevelopment and specific conditions like autism spectrum disorder (ASD). Prenatal diet is an individually modifiable factor that may alter associations with such environmental factors. The purpose of this review is to summarize studies examining prenatal dietary factors as potential modifiers of the relationship between environmental exposures and ASD or related neurodevelopmental outcomes.

RECENT FINDINGS

Twelve studies were identified; five examined ASD diagnosis or ASD-related traits as the outcome (age at assessment range: 2-5 years) while the remainder addressed associations with neurodevelopmental scores (age at assessment range: 6 months to 6 years). Most studies focused on folic acid, prenatal vitamins, or omega-3 fatty acids as potentially beneficial effect modifiers. Environmental risk factors examined included air pollutants, endocrine disrupting chemicals, pesticides, and heavy metals. Most studies took place in North America. In 10/12 studies, the prenatal dietary factor under study was identified as a significant modifier, generally attenuating the association between the environmental exposure and ASD or neurodevelopment. Prenatal diet may be a promising target to mitigate adverse effects of environmental exposures on neurodevelopmental outcomes. Further research focused on joint effects is needed that encompasses a broader variety of dietary factors, guided by our understanding of mechanisms linking environmental exposures with neurodevelopment. Future studies should also aim to include diverse populations, utilize advanced methods to optimize detection of novel joint effects, incorporate consideration of timing, and consider both synergistic and antagonistic potential of diet.

Identifying biomarkers for prenatal diagnosis of neural tube defects based on "omics"

Neural tube defects (NTDs) are the most severe birth defects and the main cause of newborn death; posing a great challenge to the affected children, families, and societies. Presently, the clinical diagnosis of NTDs mainly relies on ultrasound images combined with certain indices, such as alpha-fetoprotein levels in the maternal serum and amniotic fluid. Recently, the discovery of additional biomarkers in maternal tissue has presented new possibilities for prenatal diagnosis. Over the past 20 years, "omics" techniques have provided the premise for the study of biomarkers. This review summarizes recent advances in candidate biomarkers for the prenatal diagnosis of fetal NTDs based on omics techniques using maternal biological specimens of different origins, including amniotic fluid, blood, and urine, which may provide a foundation for the early prenatal diagnosis of NTDs.

Homocysteine-induced neural tube defects in chick embryos via oxidative stress and DNA methylation associated transcriptional down-regulation of miR-124

Although moderate homocysteine (HCY) elevation is associated with neural tube defects (NTDs), the underlying mechanisms have not been elucidated. In this study, we aimed to investigate that whether HCY-induced NTDs were associated with oxidative stress and methyl metabolism in chick embryos. The potential role of miR-124 in neurogenesis was also investigated. In this study, increased intracellular oxidative species and alterations in DNA methylation were observed following HCY treatment. This alteration coincided with decreases of Mn superoxide dismutase and glutathione peroxidase activities, as well as the expression of anti-rabbit DNA methyltransferase (DNMT) 1 and 3a. In addition, HCY induced significant decreases of S-adenosylmethionine (SAM)/S-adenosylhomocysteine (SAH) (P < 0.05). N-acetyl-L-cysteine and choline ameliorated global DNA hypomethylation induced by HCY. MiR-124 levels were significantly suppressed by HCY (P < 0.05), while elevated by 5-aza-2'-deoxycytidine (5-aza-dC). MiR-124 knockdown resulted in spina bifida occulta. Our research suggests that HCY-induced NTDs were associated with oxidative stress and methyl metabolism in chick embryos. MiR-124 down-regulation may occur via epigenetic mechanisms and contribute to HCY-induced NTDs in chick embryo models.

Effect of Pethidine Hydrochloride on the Development of Neural Tube: A Genetic Analysis Study in a Chick Embryo Model

BACKGROUND

Neural tube defects are among the most frequent congenital abnormalities of the central nervous system. Progression of neural tube deficits is affected by hereditary predilection and environmental determinants. Pethidine (meperidine) is a fast and powerful opioid analgesic in U.S. Food and Drug Administration category C. There are reports about developmental anomalies due to this medication. The aim of this study was to investigate the effects of different doses of pethidine hydrochloride on neural tube development in a chick embryo model resembling the first month of vertebral growth in mammals.

METHODS

Seventy-five specific pathogen-free eggs were incubated for 28 hours and divided into 5 groups (including the control group), each consisting of 15 eggs. Pethidine hydrochloride was administered sub-blastodermically with a Hamilton microinjector in 4 different doses. Incubation was continued until the end of the 48th hour. Subsequently, all eggs were opened, and embryos were cut from the embryonic membranes and evaluated morphologically, genetically, and histopathologically.

RESULTS

Crown-rump length, somite numbers, and silver-stained nucleolar organizer region (AgNOR) number averages, and total AgNOR/nuclear area ratios decreased in a dose-dependent manner. Examination of neural tube closure revealed statistically significant differences in all experimental groups (P<0.05). Messenger RNA levels of the BRE gene were decreased in pethidine hydrochloride-exposed embryos compared with the control group. Although this downregulation was not statistically significant, this decrease was striking with a 0.422-fold change in the fifth group.

CONCLUSIONS

We demonstrated that pethidine hydrochloride affects neuronal development in chicken embryos. The teratogenic mechanism of pethidine hydrochloride is unclear; therefore, further investigation is required.

The oxidative stress responses caused by phthalate acid esters increases mRNA abundance of base excision repair (BER) genes in vivo and in vitro

The base excision repair (BER) pathway is an important defense response to oxidative DNA damage. It is known that exposures to phthalate esters (PAEs), including Dibutyl phthalate (DBP), Mono-(2-ethylhexyl) phthalate (MEHP), and Di-(2-ethylhexyl) phthalate (DEHP), cause reactive oxygen species-induced DNA damage and oxidative stress. Here, we determined the mRNA levels of BER pathway-related genes (ogg1, nthl1, apex1, parp1, xrcc1, lig3, ung, pcna, polb, pold, fen1, and lig1), pro-apoptotic gene (bax), and apoptotic suppressor gene (bcl2) in different PAEs-exposed zebrafish larvae and HEK293T cells. Further investigations were performed to examine reactive oxygen species (ROS) accumulation, superoxide dismutase (SOD) activity, developmental toxicity, and cell viability after PAEs exposure in vivo and in vitro. The results showed that PAEs exposure can induce developmental abnormalities in zebrafish larvae, and inhibit cell viability in HEK293T cells. Additionally, we found that PAEs exposure results in the accumulation of ROS and the inhibition of SOD activation in vivo and in vitro. Notably, the mRNA levels of BER pathway-related genes (OGG1, NTHL1, APEX1, XRCC1, UNG, POLB, POLD, FEN1) were significantly upregulated after DBP or MEHP exposure, whereas the mRNA levels of NTHL1, UNG, POLB, POLD, and FEN1 were significantly altered in DEHP-treated HEK293T cells. In zebrafish, the mRNA levels of ogg1, pcna, fen1 and lig1 genes were increased after DBP or DEHP exposure, whereas the mRNA levels of nthl1, apex1, parp1, lig3, pcna and polb were decreased after MEHP exposure, respectively. Thus, our findings indicated that PAEs exposure can induce developmental toxicity, cytotoxicity, and oxidative stress, as well as activate BER pathway in vivo and in vitro, suggesting that BER pathway might play critical roles in PAEs-induced oxidative stress through repairing oxidative DNA damage.

Diethylhexyl phthalate induces teratogenic effects through oxidative stress response in a chick embryo model

Diethylhexyl phthalate (DEHP) is known as a persistent environmental pollutant. However, the possible effects of DEHP on human neural tube defects (NTDs) remain elusive. We set out to investigate the exposure of DEHP in human and explore the association of DEHP and NTDs. The level of DEHP in maternal urine was measured and analyzed by GC-MS. To further validate the results in human NTDs, chick embryos were used as animal models. Viability, reactive oxygen species (ROS) level, oxidative stress indicators and apoptosis were detected in DEHP-treated chick embryos. Our research revealed that the detection ratio of positive DEHP and its metabolites in maternal urine were observed dramatically higher in NTDs population than that in normal controls (P < 0.01, P < 0.05, respectively). Moreover, DEHP treatment (10^-6 M) led to developmental toxicity in chick embryos via accelerating oxidative stress response and cell apoptosis, and changing the level of oxidative stress-related indicators. Moreover, high dose choline (100 μg/μl) could partially restrain the toxicity effects induced by DEHP. Our data collectively imply that the incidence of NTDs may closely associate with DEHP exposure, which disturbs the development of neural tubes by enhancing oxidative stress.

Sex-Specific Programming of Cardiac DNA Methylation by Developmental Phthalate Exposure

Phthalate plasticizers are ubiquitous chemicals linked to several cardiovascular diseases in animal models and humans. Despite this, the mechanisms by which phthalate exposures cause adverse cardiac health outcomes are unclear. In particular, whether phthalate exposures during pregnancy interfere with normal developmental programming of the cardiovascular system, and the resulting implications this may have for long-term disease risk, are unknown. Recent studies suggest that the effects of phthalates on metabolic and neurobehavioral outcomes are sex-specific. However, the influence of sex on cardiac susceptibility to phthalate exposures has not been investigated. One mechanism by which developmental exposures may influence long-term health is through altered programming of DNA methylation. In this work, we utilized an established mouse model of human-relevant perinatal exposure and enhanced reduced representation bisulfite sequencing to investigate the long-term effects of diethylhexyl phthalate (DEHP) exposure on DNA methylation in the hearts of adult male and female offspring at 5 months of age (n = 5-7 mice per sex and exposure). Perinatal DEHP exposure led to hundreds of sex-specific, differentially methylated cytosines (DMCs) and differentially methylated regions (DMRs) in the heart. Pathway analysis of DMCs revealed enrichment for several pathways in females, including insulin signaling, regulation of histone methylation, and tyrosine phosphatase activity. In males, DMCs were enriched for glucose transport, energy generation, and developmental programs. Notably, many sex-specific genes differentially methylated with DEHP exposure in our mouse model were also differentially methylated in published data of heart tissues collected from human heart failure patients. Together, these data highlight the potential role for DNA methylation in DEHP-induced cardiac effects and emphasize the importance of sex as a biological variable in environmental health studies.