Developmental Exposure to Di-(2-ethylhexyl) Phthalate Induces Cerebellar Granule Cell Apoptosis via the PI3K/AKT Signaling Pathway

White matter microstructural integrity mediates associations between prenatal endocrine-disrupting chemicals exposure and intelligence in adolescents

Per- and polyfluoroalkyl substances (PFAS) and phthalic acid esters (PAEs) are well-known endocrine-disrupting chemicals (EDCs) that potentially affect child neurodevelopment. We aimed to investigate the effects of prenatal exposure to PFAS and PAEs on macro- and micro-structural brain development and intelligence in adolescents using multimodal neuroimaging techniques. We employed structural magnetic resonance imaging (MRI) and various diffusion MRI techniques, including diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI), and neurite orientation dispersion and density imaging (NODDI), to assess the gray-matter macrostructure and white-matter microstructural integrity and complexity. Participants were drawn from a birth cohort of 52 mother-child pairs in central Taiwan recruited in 2001, and the adolescent intelligence quotient (IQ) scores were assessed using the Wechsler Intelligence Scale. Nine PFAS concentrations of cord blood and maternal serum samples were obtained from the children's mothers during the third trimester of pregnancy (27-40 weeks) using a liquid chromatography system coupled to a triple-quadrupole mass spectrometer, while maternal urinary phthalates were used to evaluate PAEs exposure. Our results showed significant associations between prenatal exposure to PFAS and phthalates with changes in specific fronto-parietal regions of the adolescent male brain, including reduced cortical thickness in the inferior frontal gyrus and right superior parietal cortex, which are involved in language, memory, and executive function. A dose-response association was observed, with higher levels of PFAS and PAE exposure modulating altered white-matter fiber integrity in the superior cerebellar peduncle and inferior cerebellar peduncle of the male and female adolescent brains. In addition, higher levels of prenatal exposure to EDCs were associated with lower IQ scores in adolescents. Mediation analyses further revealed that white-matter microstructure of inter-hemispheric and cerebellar fibers mediated the association between prenatal EDC exposure and adolescent IQ scores in female adolescents. Our multimodal human neuroimaging findings suggest that prenatal exposure to EDCs may have long-lasting effects on neuroanatomical development, neural fiber connectivity, and intelligence in adolescents, and highlight the importance of using advanced diffusion imaging techniques, including DKI and NODDI, to detect neurodevelopmental changes and their brain-behavioral consequences with the risks associated with these environmental exposures.

Mitigating effect of ferulic acid on di-(2-ethylhexyl) phthalate-induced neurocognitive dysfunction in male rats with a comprehensive in silico survey

Di-(2-ethylhexyl) phthalate (DEHP) is the most abundant phthalate threatening public health-induced neurotoxicity. This neurotoxicity is associated with behavioral and biochemical deficits in male rats. Our study investigated the neuroprotective effect of ferulic acid (FA) on male rats exposed to DEHP. Thirty-two male Wistar rats were assigned to four groups. Group I control rats received corn oil, group II intoxicated rats received 300 mg/kg of DEHP, group III received 300 mg/kg of DEHP + 50 mg/kg of FA, and group IV received 50 mg/kg of FA, all agents administrated daily per os for 30 days. Anxiety-like behavior, spatial working memory, and recognition memory were assessed. Also, brain oxidative stress biomarkers, including brain malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide (NO), superoxide dismutase (SOD), brain-derived neurotrophic factor (BDNF) as well as heme oxygenase-1 (HO-1) were measured. Moreover, brain histopathology examinations associated with immunohistochemistry determination of brain caspase-3 were also evaluated. Furthermore, docking simulation was adapted to understand the inhibitory role of FA on caspase-3 and NO synthase. Compared to DEHP-intoxicated rats, FA-treated rats displayed improved cognitive memory associated with a reduced anxious state. Also, the redox state was maintained with increased BNDF levels. These changes were confirmed by restoring the normal architecture of brain tissue and a decrement in the immunohistochemistry caspase-3. In conclusion, FA has potent antioxidant and antiapoptotic properties that confirm the neuroprotective activity of FA, with a possible prospect for its therapeutic capabilities and nutritional supplement value.

An insight into sex-specific neurotoxicity and molecular mechanisms of DEHP: A critical review

Di-2-Ethylhexyl Phthalate (DEHP) is often used as an additive in polyvinyl chloride (PVC) to give plastics flexibility, which makes DEHP widely used in food packaging, daily necessities, medical equipment, and other products. However, due to the unstable combination of DEHP and polymer, it will migrate to the environment in the materials and eventually contact the human body. It has been recorded that low-dose DEHP will increase neurotoxicity in the nervous system, and the human health effects of DEHP have been paid attention to because of the extensive exposure to DEHP and its high absorption during brain development. In this study, we review the evidence that DEHP exposure is associated with neurodevelopmental abnormalities and neurological diseases based on human epidemiological and animal behavioral studies. Besides, we also summarized the oxidative damage, apoptosis, and signal transduction disorder related to neurobehavioral abnormalities and nerve injury, and described the potential mechanisms of neurotoxicity caused by DEHP. Overall, we found exposure to DEHP during the critical developmental period will increase the risk of neurobehavioral abnormalities, depression, and autism spectrum disorders. This effect is sex-specific and will continue to adulthood and even have an intergenerational effect. However, the research results on the sex-dependence of DEHP neurotoxicity are inconsistent, and there is a lack of systematic mechanisms research as theoretical support. Future investigations need to be carried out in a large-scale population and model organisms to produce more consistent and convincing results. And we emphasize the importance of mechanism research, which can enhance the understanding of the environmental and human health risks of DEHP exposure.

Calycosin mitigates chondrocyte inflammation and apoptosis by inhibiting the PI3K/AKT and NF-κB pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Shaoyao Gancao Decoction (SG-Tang), originated from the Treatise on Febrile Diseases, is often used to treat OA pain symptoms. Whereas its efficacy has been verified by several clinical studies, the underlying mechanism remained unclear. Network pharmacology and UPLC-QTOF-MS analysis found that calycosin could be regarded as the active components of SG-Tang in treating OA. However, the effect of calycosin on cartilage destruction and the pathogenesis of OA are not known. Therefore, we evaluated the benefits of calycosin for OA and revealed the underlying mechanisms.

AIM OF STUDY

Using network pharmacology, UPLC-QTOF-MS analysis and experiments, the active components of SG-Tang were analyzed to explore their potential therapeutic mechanism in OA.

MATERIALS AND METHODS

The components of SG-Tang were detected by UPLC-QTOF-MS, and the possible active components and mechanism of SG-Tang in the treatment of OA were screened by network pharmacology. The OA mouse model was constructed by DMM. In total, 30 mice were randomly divided into three groups: Sham, DMM, and DMM + Calycosin. H&E, safranin O/fast green staining and the OARSI scores were used to evaluate joint injury in mice. In addition, OA models were established using chondrocytes treated with 10 ng/mL IL-1β. Treatment groups were treated with 100, 200 or 400 μM calycosin. CCK-8 assay was used for assessing the cytotoxic effects of calycosin. TUNEL staining and Western blotting were used to detect chondrocyte apoptosis. In addition, PI3K/Akt and NF-κB signaling pathway-related markers and cartilage matrix-related indicators were also detected.

RESULTS

In vivo studies showed that calycosin inhibited IL-1β-induced IL-6 and TNF-α production, as well as iNOS and COX-2 expression. Meanwhile, calycosin could inhibit IL-1β-induced degradation of cartilage matrix, including downregulation of MMP3, MMP-13, collagen II and aggrecan. NF-κB and PI3K/AKT were also inhibited by calycosin in OA chondrocytes. Furthermore, calycosin inhibited IL-1β-induced apoptosis in mouse chondrocytes. In a mouse model of OA, our results suggest that calycosin has a chondroprotective effect.

CONCLUSIONS

According to this study, calycosin may act as a protective agent against OA by inhibiting the PI3K/AKT and NF-κB pathways. Furthermore, this study suggested that calycosin is a potential candidate for the treatment of OA.

Prenatal di-(2-ethylhexyl) phthalate exposure induced myocardial cytotoxicity via the regulation of the NRG1-dependent ErbB2/ErbB4-PI3K/AKT signaling pathway in fetal mice

Environmental sanitation of maternal contact during pregnancy is extremely important for the development of different fetal tissues and organs. In particular, during early pregnancy, any adverse exposure may cause abnormal fetal growth or inhibit the development of embryogenic organs. The potential risks of phthalate exposure, which affects the development of humans and animals, are becoming a serious concern worldwide. However, the specific molecular mechanism of di-(2-ethylhexyl) phthalate (DEHP)-induced cardiotoxicity in fetal mice remains unclear. In this study, animal models of DEHP gavage at concentrations of 250, 500, and 1000 mg/kg/day within 8.5-18.5 days of pregnancy were established. The cell proliferation, survival, and apoptosis rates were evaluated using CCK8, EdU, TUNEL and flow cytometry. The molecular mechanism was assessed via transcriptome sequencing, immunohistochemistry, immunofluorescence, reverse transcription-quantitative polymerase chain reaction, and Western blot analysis. In vivo, DEHP increased apoptosis, decreased Ki67 and CD31 expression, reduced heart weight and area, slowed down myocardial sarcomere development, and caused cardiac septal defect in fetal mice heart. Transcriptome sequencing showed that DEHP decreased NRG1 expression and downregulated the ErbB2/ErbB4-PI3K/AKT signaling pathway-related target genes. In vitro, primary cardiomyocytes were cultured with DEHP at a concentration of 150 μg/mL combined with ErbB inhibitor (AG1478, 10 μmol/L) and/or NRG1 protein (100 ng/mL) for 72 h. After DEHP intervention, the expression of NRG1 and the phosphorylation level of ErbB2, ErbB4, PI3K, and AKT decreased, and the apoptosis-related protein levels increased. Moreover, the apoptosis rate increased. After adding exogenous NRG1, the phosphorylation level of the NRG1/ERbB2/ERbB4-PI3K/AKT pathway increased, and the apoptosis-related protein levels decreased. Further, the apoptosis rate reduced. Interestingly, after exposure to DEHP and AG1478 + NRG1, the anti-apoptotic effect of NRG1 and cardiomyocyte proliferation decreased by inhibiting the NRG1/ERbB2/ERbB4-PI3K/AKT pathway. Hence, the NRG1-dependent regulation of the ERbB2/ERbB4-PI3K/AKT signaling pathway may be a key mechanism of DEHP-induced myocardial cytotoxicity.

Interrelationships among growth hormone, thyroid function, and endocrine-disrupting chemicals on the susceptibility to attention-deficit/hyperactivity disorder

Abnormal growth hormones and thyroid function may be linked to pathophysiology of attention-deficit/hyperactivity disorder (ADHD). Phthalates and bisphenol-A (BPA), two endocrine-disrupting chemicals (EDCs), may affect the human endocrine system. In this study, we aimed to perform a comprehensive investigation of whether growth hormone, thyroid function, and EDCs exhibited differential levels between ADHD patients and healthy controls. In total, 144 children with ADHD and 70 healthy control subjects were enrolled. Their endocrine systems were evaluated using the serum levels of insulin-like growth factor-1 (IGF-1), IGF-binding protein-3 (IGFBP-3), thyroid-stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), and Free T4. The urinary levels of EDCs, including monoethyl phthalate (MEP), mono-methyl phthalate (MMP), monoethylhexyl phthalate (MEHP), mono-n-butyl phthalate (MnBP), monobenzyl phthalate (MBzP), and BPA, were also examined. Patients with ADHD had lower IGF-1 levels than healthy controls (p = 0.003), but we observed no significant difference in IGFBP-3, TSH, T3, T4, or Free T4. Compared to the control group, patients with ADHD demonstrated higher MEHP levels (p = 0.043), MnBP (p = 0.033), and MBzP (p = 0.040). Furthermore, MEHP levels (p < 0.001) and BPA levels (p = 0.041) were negatively correlated with IGF-1 levels, while IGF-1 levels were negatively correlated with principal components consisting of ADHD clinical symptoms and neuropsychological performance variables. We suggest that MEHP exposure may be associated with decreased serum levels of IGF-1 and increased risk of ADHD. The mechanism underlying this association may be important for protecting children from environmental chemicals that adversely affect neurodevelopment.

Di(2-ethylhexyl) phthalate (DEHP) and thyroid: biological mechanisms of interference and possible clinical implications

Di(2-ethylhexyl) phthalate (DEHP) is a ubiquitous environmental endocrine disruptor. DEHP can be absorbed into the human body through the air, food, water, and skin. After entering the human body, DEHP is rapidly converted to mono(2-ethylhexyl) phthalate (MEHP) with greater toxicity than DEHP. An increasing number of studies indicates that DEHP or MEHP can damage the thyroid tissue and disrupt the function, but the mechanisms remain unclear. This article reviews the toxicity of DEHP on thyroid structures and functions and summarizes the potential mechanisms to provide evidence for preventing the thyroid-related diseases.

Prenatal exposure to di (2-ethylhexyl) phthalate causes autism-like behavior through inducing Nischarin expression in the mouse offspring

Epidemiologic evidence has suggested a relationship between di (2-ethylhexyl) phthalate (DEHP) prenatal exposure and autism spectrum disorders (ASD), but the underlying mechanisms are still at large unknown. In this study, pregnant mice were intragastrically administered with DEHP once a day from GD 3 to GD 17 and the neurobehavioral changes of offspring were evaluated. In addition to the repetitive stereotyped behaviors, DEHP at the concentration of 50 mg/kg/day and above significantly impaired the sociability of the offspring (P < 0.05) and decreased the density of dendritic spines of pyramidal neurons in the prefrontal cortex (P < 0.05). At the same time, the expression of Nischarin protein in prefrontal lobe increased (P < 0.05). Similarly, after 12-h incubation of DEHP at the concentration of 100 nM, the total spine density, especially the mushroom and stubby spine populations, significantly decreased in the primary cultured prefrontal cortical neurons (P < 0.05). However, the inhibitory effect of DEHP were reversed by knockdown of Nischarin expression. Collectively, these results suggest that prenatal DEHP exposure induces Nischarin expression, causes dendritic spine loss, and finally leads to autism-like behavior in mouse offspring.

Knockdown of Ptprn-2 delays the onset of puberty in female rats

In the present study, we evaluated how Ptprn-2 (encoding tyrosine phosphatase, receptor type, N2 polypeptide protein) affects the onset of puberty in female rats. We evaluated the expression of Ptprn-2 mRNA and protein in the hypothalamus-pituitary-ovary axis of female rats using real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunofluorescence at infancy, prepuberty, puberty, peripuberty, and adulthood. We evaluated the effects of Ptprn-2 gene knockdown on different aspects of reproduction-related biology in female rats, including the expression levels of puberty-related genes in vivo and in vitro, the time to onset of puberty, the concentration of serum reproductive hormones, the morphology of ovaries, and the ultrastructure of pituitary gonadotropin cells. Our results demonstrated that PTPRN-2 was primarily distributed in the arcuate nucleus (ARC), periventricular nucleus (PeN), adenohypophysis, and the ovarian follicular theca, stroma, and granulosa cells of female rats at various stages. Ptprn-2 mRNA levels significantly varied between peripuberty and puberty (P < 0.05) in the hypothalamus and pituitary gland. In hypothalamic cells, Ptprn-2 knockdown decreased the expression of Ptprn-2 and Rfrp-3 mRNA (P < 0.05) and increased the levels of Gnrh and Kiss-1 mRNA (P < 0.05). Ptprn-2 knockdown in the hypothalamus resulted in delayed vaginal opening compared to the control group (n = 12, P < 0.01), and Ptprn-2, Gnrh, and Kiss-1 mRNA levels (P < 0.05) all decreased, while the expression of Igf-1 (P < 0.05) and Rfrp-3 mRNA (P < 0.01) increased. The concentrations of FSH and P₄ in the serum of Ptprn-2 knockdown rats were lower than in control animals (P < 0.05). Large transverse perimeters and longitudinal perimeters (P < 0.05) were found in the ovaries of Ptprn-2 knockdown rats. There were fewer large secretory particles from gonadotropin cells in adenohypophysis tissue of the Ptprn-2 knockdown group compared to the control group. This indicates that Ptprn-2 knockdown can regulate levels of Gnrh, Kiss-1, and Rfrp-3 mRNA in the hypothalamus, regulate the concentration of serum FSH and P₄, and alter the morphology of ovarian and gonadotropin cells, delaying the onset of puberty in female rats.

Exposure to di-(2-ethylhexyl) phthalate reduces secretion of GDNF via interfering with estrogen pathway and downregulating ERK/c-fos signaling pathway in astrocytes

Di-(2-ethylhexyl) phthalate (DEHP) is a typical endocrine-disrupting chemical (EDC) that can increase the risk of central nervous system disease. This study aimed to investigate the in vitro and in vivo effects of DEHP exposure on GDNF secretion and the underlying mechanisms. Pregnant Wistar rats were randomly assigned into four groups and administered 0, 30, 300, or 750 mg/kg DEHP daily by oral gavage. In addition, primary astrocytes were exposed to mono-(2-ethylhexyl) phthalate (MEHP), the main metabolite of DEHP. Our results showed that DEHP exposure reduced GDNF levels and downregulated the ERK/c-fos signaling pathway in the cerebral cortex of male, but not female, offspring. Moreover, exogenous estrogen could overcome the decreased GDNF levels in astrocytes caused by MEHP exposure. MEHP also decreased p300 levels and downregulated the ERK/c-fos signaling pathway in primary astrocytes. Honokiol restored GDNF levels following MEHP exposure by activating the ERK/c-fos signaling pathway, while the inhibitor U0126 further reduced the GDNF levels. These results suggested that DEHP exposure could interfere with the normal effects of estrogen in the brain and downregulate the ERK/c-fos signaling pathway to decrease the GDNF secretion from astrocytes in the cerebral cortex.

Effects of Mono-2-ethylhexyl Phthalate on the Neural Transmission of PNs in Drosophila Antennal Lobe

Long-term exposure to different types of chemicals is hazardous to human health. Di(2-ethylhexyl) phthalate (DEHP) could exert pleiotropic deleterious effects on nervous systems. Mono(2-ethylhexyl) phthalate (MEHP), as one of the most toxic metabolites of DEHP, may have similar effects on nervous systems. However, no effects of MEHP on neural circuits have been reported. To uncover the regulation of MEHP on neural transmission, the functional changes of neural excitability and synaptic plasticity of projection neurons (PNs) have been assessed. In the current study, we recorded the action potentials (APs), stimulate action potentials (sti-APs), mini excitement postsynaptic current (mEPSC), calcium currents, and sodium currents from PNs of isolated whole brain of Drosophila model utilizing patch clamp recordings. We found that MEHP-300 (at the concentration of 300 μM), but not MHEP-100 (at the concentration of 100 μM), significantly decreased the frequency and amplitude of APs. Besides, the amplitude and anti-amplitude of sti-APs were reduced with the application of MEHP-300. Meanwhile, MEHP-300 reduced the frequency of mEPSC, but not the amplitude. Furthermore, MEHP-300 reduced the peak current densities of sodium and calcium channels. Therefore, our results indicated that MEHP could alter the neural excitability and synaptic plasticity of PNs by inhibiting the ion channels activities, revealing the potential modulation of MEHP on neural transmission of PNs.

Mechanistic insight into toxicity of phthalates, the involved receptors, and the role of Nrf2, NF-κB, and PI3K/AKT signaling pathways

The wide use of phthalates, as phthalates are used in the manufacturing of not only plastics but also many others goods, has become a main concern in the current century because of their potency to induce deleterious effects on organism health. The toxic effects of phthalates such as reproductive toxicity, cardiotoxicity, hepatotoxicity, nephrotoxicity, teratogenicity, and tumor development have been widely indicated by previous experimental studies. Some of the important mechanisms of toxicity by phthalates are the induction and promotion of inflammation, oxidative stress, and apoptosis. Awareness of the involved molecular pathways of these mechanisms will permit the detection of exact molecular targets of phthalates to protect or treat their toxicity. Up to now, various transcription factors and signaling pathways have been associated with phthalate-induced toxicity which by influencing on nuclear surface and the expression of different genes can alter cell hemostasis. In different studies, the role of nuclear factor erythroid 2-related factor 2 (Nrf2), nuclear factor-κB (NF-κB), and phosphatidylinositol-3-kinase (PI3K)/AKT signaling pathways in processes of oxidative stress, inflammation, apoptosis, and cancer has been shown following exposure to phthalates. In the present review, we aim to survey experimental studies (in vitro and in vivo) in order to show firstly the most involved receptors and also the importance and the role of the mentioned signaling pathways in phthalate-induced toxicity, and with considering this point, the future studies can focus on these molecular targets as a strategic method to reduce environmental chemicals-induced toxicity especially phthalates toxic effects.

Prenatal and breastfeeding exposure to low dose of diethylhexyl phthalate induces behavioral deficits and exacerbates oxidative stress in rat hippocampus

Diethylhexyl phthalate (DEHP) is one of the most important derivatives of phthalate that has devastating effects on nervous system function. In this study, the effects of exposure with low doses of DEHP during pregnancy and lactation periods have been evaluated in rat's puppies. DEHP at doses 5, 40, 400 μg/kg/day and 300 mg/kg/day was given to mothers by gavage during pregnancy and lactation. The spatial and working memories were evaluated by Morris water maze test and Y maze, respectively. Oxidative stress levels were measured by biochemical tests. Histopathology of hippocampal tissue was assessed using hematoxylin and eosin, Nissl staining, and immunohistofluorescence in 60-days-old puppies. Behavioral data showed that low doses of DEHP decreased the working and spatial memories of male rats. Increased oxidative stress and decreased antioxidant activity were also observed in the hippocampus of rats which received the low doses of DEHP. However, neuronal damage, inflammation, and astrocyte activation were not significantly increased in the hippocampus of rats. Overall, exposure of mothers to low doses of DEHP during pregnancy and lactation cause behavioral deficits, especially in male newborn. The destructive effects of low doses of DEHP might be mediated through increased levels of oxidative stress in the brain.

Prenatal Exposure to Endocrine-Disrupting Chemicals and Subsequent Brain Structure Changes Revealed by Voxel-Based Morphometry and Generalized Q-Sampling MRI

Previous studies have indicated that prenatal exposure to endocrine-disrupting chemicals (EDCs) can cause adverse neuropsychiatric disorders in children and adolescents. This study aimed to determine the association between the concentrations of prenatal EDCs and brain structure changes in teenagers by using MRI. We recruited 49 mother–child pairs during the third trimester of pregnancy, and collected and examined the concentration of EDCs—including phthalate esters, perfluorochemicals (PFCs), and heavy metals (lead, arsenic, cadmium, and mercury)—in maternal urine and/or serum. MRI voxel-based morphometry (VBM) and generalized q-sampling imaging (GQI) mapping—including generalized fractional anisotropy (GFA), normalized quantitative anisotropy (NQA), and the isotropic value of the orientation distribution function (ISO)—were obtained in teenagers 13–16 years of age in order to find the association between maternal EDC concentrations and possible brain structure alterations in the teenagers’ brains. We found that there are several specific vulnerable brain areas/structures associated with prenatal exposure to EDCs, including decreased focal brain volume, primarily in the frontal lobe; high frontoparietal lobe, temporooccipital lobe and cerebellum; and white matter structural alterations, which showed a negative association with GFA/NQA and a positive association with ISO, primarily in the corpus callosum, external and internal capsules, corona radiata, superior fronto-occipital fasciculus, and superior longitudinal fasciculus. Prenatal exposure to EDCs may be associated with specific brain structure alterations in teenagers.

Maternal Exposure to Di-(2-ethylhexyl) Phthalate Impairs Hippocampal Synaptic Plasticity in Male Offspring: Involvement of Damage to Dendritic Spine Development

Exposure to di-(2-ethylhexyl) phthalate (DEHP), a widely used kind of plasticizer, can result in neurodevelopment impairments and learning and memory disorders. We studied the effects and possible mechanisms of maternal DEHP treatment on hippocampal synaptic plasticity in offspring. Pregnant Wistar rats were randomly divided into four groups and received 0, 30, 300, 750 (mg/kg)/d DEHP by gavage from gestational day (GD) 0 to postnatal day (PN) 21. Our data showed that DEHP exposure impaired hippocampal synaptic plasticity, damaged synaptic ultrastructure, and decreased synaptic protein levels in male pups. Furthermore, DEHP decreased the density of dendritic spines, affected F-actin polymerization, and downregulated the Rac1/PAK/LIMK1/cofilin signaling pathway in male offspring. However, the alterations in the hippocampi of female offspring were not observed. These results illustrate that maternal DEHP exposure could impair hippocampal synaptic plasticity by affecting synaptic structure and dendritic spine development in male offspring, which may be attributed to altered cytoskeleton construction induced by downregulation of the Rac1/PAK/LIMK1/cofilin signaling pathway.

A multi-omics approach reveals molecular mechanisms by which phthalates induce cardiac defects in zebrafish (Danio rerio)

The potential risks of phthalates affecting human and animal health as well as the environment are emerging as serious concerns worldwide. However, the mechanism by which phthalates induce developmental effects is under debate. Herein, we found that embryonic exposure of zebrafish to di-(2-ethylhexyl) phthalate (DEHP) and di-butyl phthalate (DBP) increased the rate of heart defects including abnormal heart rate and pericardial edema. Changes in the transcriptional profile demonstrated that genes involved in the development of the heart, such as tbx5b, nppa, ctnt, my17, cmlc1, were significantly altered by DEHP and DBP at 50 μg/L, which agreed with the abnormal cardiac outcomes. Methylated DNA immunoprecipitation sequencing (MeDIP-Seq) further showed that significant hypomethylation of nppa and ctnt was identified after DEHP and DBP exposure, which was consistent with the up-regulation of these genes. Notably, hypermethylation on the promoter region (<1 kb) of tbx5b was found after DEHP and DBP exposure, which might be responsible for its decrease in transcription. In conclusion, phthalates have the potential to induce cardiac birth defects, which might be associated with the transcriptional regulation of the involved developmental factors such as tbx5b. These findings would contribute to understand the molecular pathways that mediated the cardiac defects caused by phthalates.

Antidiabetic Activity of Gold Nanoparticles Synthesized Using Wedelolactone in RIN-5F Cell Line

We synthesized the gold nanoparticles (AuNPs) using wedelolactone (WDL) and characterized them using UV-visible spectroscopy, fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopic (SEM), transmission electron microscopic (TEM), energy dispersive X-ray diffraction, and atomic force microscopic (AFM) studies. The electronic spectrum exhibited an absorption peak at 535 nm. The FT-IR results proved that WDL was stabilized on the surface of AuNPs by acting as a capping or reducing agent. The crystalline structure was affirmed by XRD pattern and the spherical shape of WDL-AuNPs was evidenced by SEM, TEM, and AFM. The synthesized WDL-AuNPS were evaluated for anti-diabetic activity in pancreatic RIN-5F cell lines. In vitro results showed that WDL-AuNPs did not only improve the insulin secretion affected by di-(2-ethylhexyl) phthalate (DEHP), but also the cell viability in RIN5F cells. WDL-AuNPs treatment modulates the pro-apoptotic proteins and anti-apoptotic proteins expression to prevent the cells undergoing apoptosis in DEHP-exposed RIN-5F cells. The exposure of DEHP causes an increase in ROS production and lipid peroxidation levels. The free radical scavenging and antioxidant properties of WDL-AuNPs increase the deleterious effect caused by DEHP. On the other side, WDL-AuNPs increase mRNA expressions of insulin-signaling proteins in RIN-5F cells. This study concludes that WDL-AuNPs can be successfully used to regulate the expression of Bcl-2 family proteins, reduce lipid peroxidation, and to improve the secretion of antioxidants and insulin through the GLUT2 pathway in RIN-5F cell lines.

The interference of DEHP in precocious puberty of females mediated by the hypothalamic IGF-1/PI3K/Akt/mTOR signaling pathway

DEHP is reported to cause precocious puberty of females in both humans and rodents, but the underlying mechanisms were largely unknown. This study was designed to clarify the effects and the mechanisms of DEHP on the pathogenesis of sexual precocity. Prepubertal female rats were treated with DEHP for 4 weeks. Key organs were analyzed in control conditions and after exposure to 0.2, 1, and 5 mg/kg/day DEHP in pubertal female rats. To determine the role of the IGF-1/PI3K/Akt/mTOR signaling pathway in DEHP-induced female precocious puberty, 36 rats were treated with 5 mg/kg/day DEHP to establish a model of female precocious puberty. And we investigated the expression of genes and proteins related to IGF-1 pathway in rat hypothalamus after treatment with inhibitors. In the present study, we observed that DEHP treatment resulted in earlier vaginal opening time, higher number of Nissl bodies in the hypothalamus neurons, lower apoptosis of hypothalamic cells, higher IGF-1 and GnRH levels in the serum and hypothalamus. DEHP could also upregulated the expression of IGF-1/PI3K/Akt/mTOR pathway and GnRH in the hypothalamus of adolescent female rats, and inhibition of IGF-1R and mTOR in hypothalamus could block the activation of Kiss-1, GPR54, and GnRH by DEHP. In summary, our study suggested that DEHP might activate the hypothalamic GnRH neurons prematurely through the IGF-1 signaling pathway and promote GnRH release, leading to the initiation of female sexual development. Our results provide a new molecular mechanism underlying reproductive and developmental toxicity in pubertal female rats induced by DEHP.