Nicotine exposure declines quality of early embryos and disrupts placental structure by destabilizing Notch signaling pathway
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ABSTRACT: Nicotine is a common environmental pollution which is diffused into the air in the form of cigarette smoke fumes. Due to its lipophilic nature, nicotine can rapidly transport through membrane barriers and spread throughout the body which leads to abnormalities in the human brain, heart and even the fatal. However, the effects of nicotine on early embryonic development remains elusive. In this study, we found that nicotine significantly affected early embryonic development with decreased blastocyst formation. In addition, embryos treated with nicotine caused increased level of ROS, DNA damage and cell apoptosis. By RNA sequencing analysis, we demonstrated that nicotine affected the expression of placental development genes. Consistently, we found that the placental development at E17.5 was impaired by nicotine exposure, with increased placental weight and disrupted placental structure. This was due to excessive activation of the Notch signaling pathway, since blocking Notch signal by DAPT treatment recovered abnormal placental weight and structure induced by nicotine exposure. We also observed that nicotine exposure could specifically cause promoter hypermethylation of Phlda2 (a maternally expressed imprinted gene associated with placental development) and lead to its abnormal expression. Overall, this study provides evidence that nicotine causes the declining quality of early embryo and leads to placental abnormalities related with over-activation of the Notch signaling pathway.
Project description:Assisted Reproductive Technologies (ART) employ gamete/embryo handling and culture in vitro to produce offspring. ART pregnancies have increased risk of low birth weight, abnormal placentation, pregnancy complications, and imprinting disorders. We and others have previously shown that embryo culture induces low birth weight, abnormal placental morphology, and lower levels of DNA methylation in placentas in a mouse model of ART. We hypothesized that these adverse effects are linked to a subtle disruption of specific biological processes during preimplantation development. To test this hypothesis, we performed embryo culture for several discrete periods of preimplantation development and assessed fetal and placental outcomes at term. We observed a reduction in fetal:placental ratio in two distinct windows of preimplantation embryo development, while placental morphological abnormalities and reduced imprinting control region methylation were associated with culture prior to the morula stage. We also provide evidence that extended culture to the blastocyst stage induces additional placental DNA methylation changes compared to embryos transferred at the morula stage, and that female concepti exhibited a higher loss of DNA methylation than males. Altogether, this study identifies specific developmental windows of susceptibility and potential targets for embryo culture optimization.
Project description:Nicotine, the main constituent of tobacco, is highly detrimental to the developing fetus by increasing the risk of gestational complications and organ disorders. The effects of nicotine on human embryonic development and related mechanisms, however, remain largely unresolved. Here, we performed single-cell RNA-sequencing (scRNA-seq) of human embryonic stem cell (hESC)-derived embryoid body (EB) in the presence or absence of nicotine. Nicotine induced lineage-specific responses and dysregulated cell-to-cell communication in EBs, shedding light on the adverse effects of nicotine on human embryonic development. Additionally, nicotine reduced cell viability, increased reactive oxygen species (ROS), and altered cell cycling in EBs. Abnormal Ca2+ signaling was found in muscle cells upon nicotine exposure and verified in hESC-derived cardiomyocytes. Consequently, our scRNA-seq data suggests direct adverse effects of nicotine on hESC differentiation at the single-cell level and offers new method for evaluating drug and environmental toxicity on human embryonic development in utero.
Project description:Piglets cloned by somatic cell nuclear transfer (SCNT) show a high incidence of malformations and a high death rate during the perinatal period. To investigate the underlying mechanisms for abnormal development of cloned pig fetuses, we compared body weight, amniotic fluid (AF) metabolome, and placental transcriptome between SCNT- and artificial insemination (AI)-derived pig fetuses. Results showed that the body weight of SCNT pig fetuses was significantly lower than that of AI pig fetuses. The identified differential metabolites between the two groups of AF were mainly involved in bile acids and steroid hormones. The levels of all detected bile acids in SCNT AF were significantly higher than those in AI AF. The increase in the AF bile acid levels in SCNT fetuses was linked with the downregulation of placental bile acid transporter expression and the abnormal development of placental folds (PFs), both of which negatively affected the transfer of bile acids from AF across the placenta into the mother's circulation. Alteration in the AF steroid hormone levels in cloned fetuses was associated with decreased expression of enzymes responsible for steroid hormone biosynthesis in the placenta. In conclusion, cloned pig fetuses undergo abnormal intrauterine development associated with alteration of bile acid and steroid hormone levels in AF, which may be due to the poor development of PFs and the erroneous expression of bile acid transporters and enzymes responsible for steroid hormone biosynthesis in the placentas.
Project description:Background. Prenatal exposure to nicotine has been documented to impose numerous deleterious effects on fetal development. However, the epigenetic changes promoted by nicotine exposure on germ cell are still not well understood. Objectives. In this study, we focused on elucidating the impact of prenatal nicotine exposure on regulatory epigenetic mechanisms important for the germ cells development. Objectives. In this study, we focused on elucidating the impact of prenatal nicotine exposure on regulatory epigenetic mechanisms important for the germ cells development.
Project description:Background. Prenatal exposure to nicotine has been documented to impose numerous deleterious effects on fetal development. However, the epigenetic changes promoted by nicotine exposure on germ cell are still not well understood. Objectives. In this study, we focused on elucidating the impact of prenatal nicotine exposure on regulatory epigenetic mechanisms important for the germ cells development. s important for the germ cells development
Project description:Nonsyndromic cleft palate is a common birth defect (1:700) with a complex etiology involving both genetic and environmental risk factors. Nicotine, a major teratogen present in tobacco products, was shown to cause alterations and delays in the developing fetus. To demonstrate the effect of nicotine on craniofacial development, particularly palatogenesis, we delivered three different doses of nicotine (1.5, 3.0 and 4.5 mg/kg/day) into pregnant BALB/c mice throughout their entire pregnancy using subcutaneous osmotic mini-pump. We assessed the pups for morphological anomalies, as well as genome-wide mRNA (transcriptome) microarray analysis. Consistent administration of nicotine caused developmental retardation, still birth, low birth weight, and significant palatal size and shape abnormality in the pups. However, it did not cause obvious cleft palate. The microarray data analysis using IPA identified differential expression of genes involved in various biological pathways, particularly cancer, genetic diseases, and tissue development in response to consistent nicotine exposure. 6232 up-regulated and 6310 down-regulated genes were detected in nicotine-treated groups compared to the control. Moreover, 45% of the genes associated with cleft palate were found to be affected by nicotine. Alterations of a subset of differentially expressed genes were illustrated with hierarchal clustering and RT-PCR. We concluded that consistent nicotine exposure during pregnancy interferes with normal growth and development of the fetus including palatogenesis; however, this interference does not result in cleft palate, rather smaller palate size with persistent MES. To our knowledge, this is the first experiment revealing the impact of nicotine on the fetal palate transcriptome in mice.
Project description:Background: Healthy individuals exposed to low levels of cigarette smoke have a decrement in lung function and higher risk for lung disease compared to unexposed individuals. We hypothesized that healthy individuals exposed to low levels of tobacco smoke must have biologic changes in the small airway epithelium compared to healthy unexposed individuals. Methods: Small airway epithelium was obtained by bronchoscopy from 121 individuals; microarrays assessed genome wide gene expression, and urine nicotine and cotinine were used to categorized subjects as “nonsmokers,” “active smokers,” and “low exposure.” The gene expression data was used to determine the threshold and ID50 of urine nicotine and cotinine at which the small airway epithelium showed abnormal responses. Results: There was no threshold of urine nicotine without an abnormal small airway epithelial response, and only a slightly above detectable threshold abnormal response for cotinine. The nicotine ID50 for nicotine was 25 ng/ml and cotinine 104 ng/ml. Conclusions: The small airway epithelium detects and responds to low levels of tobacco smoke with transcriptome modifications. This provides biologic correlates of epidemiologic studies linking low level tobacco smoke exposure to lung health risk, health, identifies genes in the lung cells most sensitive to tobacco smoke and defines thresholds at the lung epithelium responds to inhaled tobacco smoke.
Project description:There is increasing concern regarding the adverse effects of air pollution on human health, and benzene is a major toxic compound in air pollution. Maternal benzene exposure has been associated with reproductive complications, such as preterm birth, low birth weight, and immunological and neurological complications in the offspring. However, it is poorly understood how benzene induces these complications. Our objective was to establish a full body inhalation mouse model for maternal benzene exposure that mimics clinical phenotypes observed in human populations, and characterize the maternal immune activation and placental response in our model. Here, we report that maternal immune activation triggered by benzene exposure during pregnancy leads to increased resorptions, abnormal placenta development and low birth weight of fetus. More importantly, there is a sexual dimorphic response to benzene exposure in female and male placentas. In the male placenta, the transcriptome changes reveal a more immunologically relevant profile, while females have a metabolically related profile. Furthermore, we discover the sexual dimorphic response could be a consequence of the sexual dimorphism of placenta at baseline, which indicates the significant difference between sexes in terms of the immunological processes in the placenta, both in human and mouse. Therefore, our findings established a benzene exposure mouse model and indicated the sexual dimorphism of placenta, which provides valuable reference for the future pregnancy studies.
Project description:Nonsyndromic cleft palate is a common birth defect (1:700) with a complex etiology involving both genetic and environmental risk factors. Nicotine, a major teratogen present in tobacco products, was shown to cause alterations and delays in the developing fetus. To demonstrate the effect of nicotine on craniofacial development, particularly palatogenesis, we delivered three different doses of nicotine (1.5, 3.0 and 4.5 mg/kg/day) into pregnant BALB/c mice throughout their entire pregnancy using subcutaneous osmotic mini-pump. We assessed the pups for morphological anomalies, as well as genome-wide mRNA (transcriptome) microarray analysis. Consistent administration of nicotine caused developmental retardation, still birth, low birth weight, and significant palatal size and shape abnormality in the pups. However, it did not cause obvious cleft palate. The microarray data analysis using IPA identified differential expression of genes involved in various biological pathways, particularly cancer, genetic diseases, and tissue development in response to consistent nicotine exposure. 6232 up-regulated and 6310 down-regulated genes were detected in nicotine-treated groups compared to the control. Moreover, 45% of the genes associated with cleft palate were found to be affected by nicotine. Alterations of a subset of differentially expressed genes were illustrated with hierarchal clustering and RT-PCR. We concluded that consistent nicotine exposure during pregnancy interferes with normal growth and development of the fetus including palatogenesis; however, this interference does not result in cleft palate, rather smaller palate size with persistent MES. To our knowledge, this is the first experiment revealing the impact of nicotine on the fetal palate transcriptome in mice. Total 8 samples were analyzed. Using an osmotic minipump, duplicate samples from palates of either sterile physiological saline or nicotine (1.5 mg/kg/day, 3.0 mg/kg/day, or 4.5 mg/kg/day)-treated newborn pups.