Teratogenic Mechanisms Research Articles

Coadministration of ARV (Atripla) and Topiramate disrupts quail cardiac neural crest cell migration.

Congenital anomalies such as ventricular septal defects and truncus communis have been reported with the prenatal use of antiretroviral therapy. The mechanism of antiretroviral therapy teratogenicity is unclear and is therefore the focus of this study. Some human immunodeficiency virus patients on antiretrovirals are placed on antiepileptic drugs which are also teratogenic. The interactive effects arising from this therapeutic combination may affect their teratogenic propensity through their effects on neural crest cell migration. Appropriately cultured neural crest cells from dissected neural tubes of 32-hr old quail embryos exposed to culture media containing peak plasma levels of Atripla, Topiramate and the combination of both were studied. Distance of migration of neural crest cells was measured using the migration assay and the cells were stained with rhodamine phalloidin to evaluate the cell actin. Also quail neural crest cells were brought into suspension and microinjected into chick hosts to determine the migration of the cells to the interventricular septum. Migration of cultured neural crest cells was extensive in the control cultures, but inhibited in the treated groups. The experimental cultures showed a disarray of actin cytoskeleton contrary to normal distribution of actin filaments in controls. Significantly, few quail neural crest cells migrated to the interventricular septum of chick host embryos compared to the control cultures. The coadministration of topiramate with antiretroviral therapy does not seem to affect the activity of the antiretroviral drug. These results indicate that Atripla and Topiramate cause ventricular septal defects by inhibiting the migration of cardiac neural crest cells.

Cellular and molecular mechanisms in the development of a cleft lip and/or cleft palate; insights from zebrafish (Danio rerio).

Human cleft lip and/or palate (CLP) are immediately recognizable congenital abnormalities of the face. Lip and palate develop from facial primordia through the coordinated activities of ectodermal epithelium and neural crest cells (NCCs) derived from ectomesenchyme tissue. Subtle changes in the regulatory mechanisms of NCC or ectodermal epithelial cells can result in CLP. Genetic and environmental contributions or a combination of both play a significant role in the progression of CLP. Model organisms provide us with a wealth of information in understanding the pathophysiology and genetic etiology of this complex disease. Small teleost, zebrafish (Danio rerio) is one of the popular model in craniofacial developmental biology. The short generation time and large number of optically transparent, easily manipulated embryos increase the value of zebrafish to identify novel candidate genes and gene regulatory networks underlying craniofacial development. In addition, it is widely used to identify the mechanisms of environmental teratogens and in therapeutic drug screening. Here, we discuss the value of zebrafish as a model to understand epithelial and NCC induced ectomesenchymal cell activities during early palate morphogenesis and robustness of the zebrafish in modern research on identifying the genetic and environmental etiological factors of CLP.

Exposure to environmental bisphenol A inhibits HTR-8/SVneo cell migration and invasion.

Environmental pollutants, such as bisphenol A (BPA) have recently been implicated in the development of adverse birth outcomes. However, the underlying teratogenic mechanisms remain unclear. We investigated the effects of BPA on the migration and invasion of human primary extravillous trophoblast HTR-8/SVneo cells. Our results indicated that BPA reduced cell migration and invasion. Moreover, it altered the ratio of matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) by downregulating MMP-2 and MMP-9, and upregulating TIMP-1 and TIMP-2. Furthermore, BPA suppressed integrin β1, integrin α5, and vimentin. Interestingly, BPA-induced invasion was partially restored by G15, a membrane G-protein-coupled estrogen receptor 30 antagonist. We further revealed that 42 proteins were differentially expressed by mass spectrometry analysis, which could be divided into three categories based on gene ontology including biological process, cellular component, and molecular function. These results suggest that BPA reduces HTR-8/SVneo cell migration and invasion by downregulating MMP-2 and MMP-9, up-regulating TIMP-1 and TIMP-2, and suppressing adhesion molecules.

The Teratogenic Mechanism of Echinochrome as a Hypoglycemic Agent on Wistar Rats

Background: Echinochrome (Ech) is the active ingredient in the Histochrome drug, which possesses strong antioxidant, hypolipidemic and hypoglycemic activity. Objective: The present work aimed to characterize the malformations induced by moderate and high dose of Ech during pregnancy. Methods: In this study, eighteen (18) female pregnant rats were assigned into 3 groups (6 rats/ group); control group, low dose Ech (0.1 mg/kg) and high dose Ech (1 mg/kg). Results: The high dose of Ech caused a significant decrease in the number of embryos, uteri weight, body weight gain, placenta weight, and embryo weight and length. Also, the high dose led to a significant increase in serum AST, ALT, ALP, urea and uric acid of mothers. Conclusion: Our findings revealed the first teratogenic effects of high dose Ech. The teratogenic mechanism of Ech works through induction of the hypoglycemic condition in pregnant rats.

Of embryos and tumors: Cyclopia and the relevance of mechanistic teratology.

Embryos and tumors share several characteristics, but embryos differ from tumors in their coordination of cellular- and tissue-level processes, including organized differentiation, remodeling of tissues through apoptosis, and disciplined migrations of cells. Embryonic cellular events are kept on track through orderly cell-cell communication via signal transduction pathways. If the pathways are disrupted, development is perturbed, and malformation may result. Despite profound differences between embryos and tumors, the study of one has benefited our understanding of the other. Using cyclopia as an example, the history of humans' beliefs concerning and reactions to this horrific malformation are explored. During the latter half of the 20th century, interest in cyclopic sheep from high pastures in western Idaho led to the discovery that cyclopia occurred after pregnant ewes foraged in fields containing corn lily (Veratrum californicum). Eventually, the proximate teratogen was identified as cyclopamine (a steroidal alkaloid). The teratogenic mechanism was identified as inhibition of the sonic hedgehog (Shh) signal transduction pathway. Alert cancer researchers noted that a prominent form of medulloblastoma (a devasting childhood brain tumor) overexpressed Shh. Cyclopamine effectively inhibited the tumor in mice and killed human medulloblastoma cells in vitro. Thus, over a 60-year period, a molecule causing hideous malformations and much emotional pain was discovered and then found capable of restraining a destructive tumor, potentially saving children's lives and sparing emotional devastation of their families. The success of identifying cyclopamine as a cause of cyclopia and a potential cure for medulloblastoma emerged from mechanistic research shared by multiple disciplines.

Potential mechanisms underlying embryonic developmental toxicity caused by benzo[a]pyrene in Japanese medaka (Oryzias latipes).

Polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (BaP), are widely distributed in air, water, and sediments; however, limited data are available regarding their potential adverse effects on the early life stages of fish. In this study, we evaluated the embryonic teratogenicity and developmental toxicity of BaP in Japanese medaka (Oryzias latipes) using a nanosecond pulsed electric field (nsPEF) technique and predicted their molecular mechanisms via transcriptome analysis. The gas chromatography/mass spectrometry analyses revealed that the BaP was efficiently incorporated into the embryos by nsPEF treatment. The embryos incorporating BaP presented typical teratogenic and developmental effects, such as cardiovascular abnormalities, developmental abnormalities, and curvature of backbone. DNA microarray analysis revealed several unique upregulated genes, such as those involved in cardiovascular diseases, various cellular processes, and neural development. Furthermore, the gene set enrichment and network analyses found several genes and hub proteins involved in the developmental effects of BaP on the embryos. These findings suggest a potential mechanism of teratogenicity and developmental toxicity caused by exposure to BaP. The nsPEF and transcriptome analyses in combination can be effective for evaluating the potential effects of chemical substances on medaka embryos.

Characterizing the effects of in utero exposure to valproic acid on murine fetal heart development.

Recently, the use of the antiepileptic drug valproic acid (VPA) for the treatment of psychiatric conditions has been on the rise. However, studies have shown that in utero VPA exposure can affect embryonic development, including being associated with congenital heart defects. One proposed mechanism of VPA-initiated teratogenicity is the inhibition of histone deacetylase, which is involved in the regulation of transcription factors that regulate cardiogenesis. Myocyte enhancing factor 2C (Mef2c), a transcription factor involved in the development of cardiac structure and cardiomyocyte differentiation, has been shown to increase in response to in utero VPA exposure, associating with contractile dysfunction and myocardial disorganization. To characterize the effects of VPA on murine heart development, pregnant CD-1 mice were dosed with 400 mg/kg of VPA on gestational day (GD) 9. Using high-resolution ultrasound, we examined the effects of VPA on cardiac contractile function on GD 14-18, with fetal hearts being harvested on GD 19 for histological analysis. Lastly, we conducted quantitative real-time polymerase chain reaction to measure the relative Mef2c gene expression in GD 16 murine hearts. We observed structural anomalies at GD 19 in the hearts of VPA-treated mice. Additionally, our results showed alterations in measures of cardiac contractility, with a decrease or increase in cardiac contractile ability in VPA-treated mice depending on the GD and measurement taken. These results further characterize the effects of VPA on heart development and suggest that alterations in Mef2c gene expression, at least on GD 16, do not mediate VPA-induced cardiotoxicity in CD-1 mice.

Effectiveness of Risk Minimization Measures to Prevent Pregnancy Exposure to Mycophenolate-Containing Medicines in Europe.

In 2015, the European Medicines Agency (EMA) requested additional Risk Minimization Measures (RMM), consisting of a Direct Healthcare Professional Communication (DHPC), a Guide for Healthcare Professionals (HCPs), and a Guide for Patients, to prevent pregnancy exposure to mycophenolate-containing medicines. This study assessed the effectiveness of the additional RMM for any mycophenolate-containing medicine among prescribers of these products in Europe. A cross-sectional survey was conducted among prescribers of mycophenolate-containing medicines in five European countries via the administration of 19 questions checking knowledge levels for the key messages included in the additional RMM. Of 79,783 invitations sent to potential prescribers of mycophenolate-containing medicines, 295 HCPs accessed the survey, giving an overall response rate of 0.4% (range 0.1-8.6%). A total of 231 prescribers were included in the primary analysis. Knowledge levels for 15 questions was fair (50 to < 70%) to high (≥ 70%), and for 4 questions was poor (< 50%). Highest knowledge (≥ 75%) was for knowing that mycophenolate is contraindicated in women of childbearing potential not using highly effective contraception (80.3%) and that mycophenolate should not be routinely prescribed during pregnancy (77.5%). Lowest knowledge (≤ 30%) was for knowing that no specific mechanism of teratogenicity and mutagenicity has been identified for mycophenolate (23.4%). Less than half of HCPs reported receipt of the DHPC (42.5%) or were aware of the Guide for HCPs (32.1%) and Guide for Patients (29.7%). The most frequently reported primary source from which HCPs learned about these risks was the Summary of Product Characteristics (SmPC; 33.8%), while only 9.9% indicated the Guide for HCPs. Prescribers who participated in this survey appear to be reasonably well informed about the key messages of the RMM put in place in Europe for mycophenolate-containing medicines. The relatively high knowledge levels, in spite of the low proportion of HCPs reporting receipt of the additional RMM, suggest that the SmPC may be sufficiently informing prescribers about the pregnancy risks of mycophenolate-containing medicines and actions recommended to minimize pregnancy risk. Nevertheless, Roche in consultation with EMA will continue to distribute all additional RMM.

Molecular mechanisms of Cisplatin- induced placental toxicity and teratogenicity in rats and the ameliorating role of N-acetyl-cysteine

The aim of the present study is to investigate the molecular mechanisms of Cisplatin- induced placental toxicity and teratogenicity in rats and the ameliorating role of N-acetyl-cysteine (NAC). Cisplatin was administrated intraperitoneally at 5 mg/kg.b.wt as a single dose on the 12th day of gestation while NAC was administered orally throughout gestation either alone or in concomitant injection of Cisplatin at 200 mg/kg.b.wt. Cisplatin + NAC group showed reduction in the elevated morphological, visceral and skeletal abnormalities as well as the morphological and histopathological changes in placenta compared to Cisplatin - treated rats. Importantly, NAC attenuated Cisplatin-induced placental apoptosis through down-regulation of Fas and Caspase-3 genes expression. In conclusion, induction of placental apoptosis by overexpression of Fas and Caspase-3 genes gives a new insight into the mechanism of Cisplatin teratogenicity. The protective role of NAC, on the other hand, was characterized by attenuation of Fas and Caspase-3 genes- mediated apoptosis.

Direct Reprogramming of Human Neurons Identifies MARCKSL1 as a Pathogenic Mediator of Valproic Acid-Induced Teratogenicity.

Human pluripotent stem cells can be rapidly converted into functional neurons by ectopic expression of proneural transcription factors. Here we show that directly reprogrammed neurons, despite their rapid maturation kinetics, can model teratogenic mechanisms that specifically affect early neurodevelopment. We delineated distinct phases of invitro maturation during reprogramming of human neurons and assessed the cellular phenotypes of valproic acid (VPA), a teratogenic drug. VPA exposure caused chronic impairment of dendritic morphology and functional properties of developing neurons, but not those of mature neurons. These pathogenic effects were associated with VPA-mediated inhibition of the histone deacetylase (HDAC) and glycogen synthase kinase-3 (GSK-3) pathways, which caused transcriptional downregulation of many genes, including MARCKSL1, an actin-stabilizing protein essential for dendritic morphogenesis and synapse maturation during early neurodevelopment. Our findings identify a developmentally restricted pathogenic mechanism of VPA and establish the use of reprogrammed neurons as an effective platform for modeling teratogenic pathways.

The effect of diclofenac sodium on neural tube development in the early stage of chick embryos.

Neural tube defects are congenital malformations of the central nervous system. Genetic predisposition and some environmental factors play an important role in the development of neural tube defects. This study aimed to investigate the effects of diclofenac sodium on the neural tube development in a chick embryo model that corresponds to the first month of vertebral deve- lopment in mammals. Seventy-five fertile, specific pathogen-free eggs were incubated for 28 h and were divided into five groups of 15 eggs each. Diclofenac sodium was administered via the sub-blastodermic route at this stage. Incubation was continued till the end of the 48th h. All eggs were then opened and embryos were dissected from embryonic membranes and evaluated morphologically and histopathologically. It was determined that the use of increasing doses of diclofenac sodium led to defects of midline closure in early chicken embryos. There were statistically significant differences in neural tube positions (open or close) among the groups. In addition; crown-rump length, somite number were significantly decreased in high dose experimental groups compared with control group. This study showed that development of neurons is affected in chi- cken embryos after administration of diclofenac sodium. The exact teratogenic mechanism of diclofenac sodium is not clear; therefore it should be investigated.

Study on the Potential Biomarkers of Maternal Urine Metabolomics for Fetus with Congenital Heart Diseases Based on Modified Gas Chromatograph-Mass Spectrometer.

Background There has been significant research on the genetic and environmental factors of congenital heart defects (CHDs), but few causes of teratogenicity, especially teratogenic mechanisms, can be clearly identified. Metabolomics has a potential advantage in researching the relationship between external factors and CHD. Objective To find and identify the urinary potential biomarkers of pregnancy (including in the second and third trimesters) for fetuses with CHD based on modified gas chromatograph-mass spectrometer (GC-MS), which could reveal the possibility of high-risk factors for CHD and lay the foundation for early intervention, treatment, and prevention. Methods Using a case-control design, we measured the urinary potential biomarkers of maternal urine metabolomics based on GC-MS in a population-based sample of women whose infants were diagnosed with CHD (70 case subjects) or were healthy (70 control subjects). SIMCA-P 13.0 software, principal component analysis (PCA), orthogonal partial least squares-discriminant analysis (OPLS-DA), Wilcoxon-Mann-Whitney test, and logistics regression were used to find significant potential biomarkers. Result The 3D score graph of the OPLS-DA showed that the CHD and control groups were fully separated. The fitting parameters were R2x=0.78 and R2y=0.69, and the forecast rate was Q2=0.61, indicating a high forecast ability. According to the ranking of VIPs from the OPLS-DA models, we found 34 potential metabolic markers with a VIP > 1, and after two pairwise rank sum tests, we found 20 significant potential biomarkers, which were further used in multifactor logistic regressions. Significant substances, including 4-hydroxybenzeneacetic acid (OR=4.74, 95% CI: 1.06-21.06), 5-trimethylsilyloxy-n-valeric acid (OR=15.78, 95% CI: 2.33-106.67), propanedioic acid (OR=5.37, 95% CI: 1.87-15.45), hydracrylic acid (OR=6.23, 95% CI: 1.07-36.21), and uric acid (OR=5.23, 95% CI: 1.23-22.32), were associated with CHD. Conclusion The major potential biomarkers in maternal urine associated with CHD were 4-hydroxybenzeneacetic acid, 5-trimethylsilyloxy-n-valeric acid, propanedioic acid, hydracrylic acid, and uric acid, respectively. These results indicated that the short chain fatty acids (SCFAs) and aromatic amino acid metabolism may be relevant with CHD.

Maternal Alcohol Exposure Augments Fetal Skeletal Anomalies in Diabetic Mouse Pregnancy

IntroductionThere is a several‐fold increase in birth defects in diabetic pregnancy. Alcohol is an established‐teratogen in humans. Both alcohol and diabetes mellitus (DM) are independent risk factors for congenital anomalies. However, their teratogenic mechanisms are unknown. Diabetic women also might consume alcohol during pregnancy.AimOur aim was to determine the effects of potential interaction between maternal alcohol and maternal DM during gestation on fetal development.MethodsWe made pregnant mice diabetic by a single dose (IP) of the diabetogenic compound streptozotocin (STZ) administered on gestation day (GD) 2. Controls received a proportionate volume of vehicle (citrate buffer). Groups of DM and non‐DM animals received ethanol (IP) in single doses of 0.03 ml/g body weight (25% v/v ethanol in normal saline) on GD 7 or 8. One group of DM animals had a daily dose of 6–8 IU of insulin subcutaneously. We collected the fetuses on GD 18, fixed in 95% ethanol and stained their skeletons with Alizarin red‐S and Alcian blue and observed for skeletal anomalies.ResultsBoth ethanol and DM independently induced a low incidence of skeletal defects in fetuses. Ethanol injection of DM mice on GD 7 resulted in a moderate accentuation of DM‐related skeletal defects. Treatment of DM animals with ethanol on GD 8 resulted in severe skeletal defects, which affected regions of the axial and appendicular skeletons differentially. The combination treatment affected most markedly skeletal ossification in about 60% of animals. This treatment also caused an augmented frequency of skeletal variations (e.g. supernumerary ribs and sternal anomalies) and poor ossification of the bones of fore‐, and hind paws.Discussion and ConclusionGestation day 8 was particularly susceptible to augmentation of skeletal defects with ethanol treatment. These data also suggest that alcohol‐diabetes interaction affects the ossification processes of mouse embryos resulting in extensive skeletal variations and malformations.Support or Funding InformationSupported by (1) College of Medicine and Health Sciences, UAE University, Al Ain, UAE and (2) School of Medicine, University of Texas Rio Grande Valley, Edinburg, TXThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Ethanol promotes differentiation of embryonic stem cells through retinoic acid receptor-γ

Ethanol (EtOH) is a teratogen, but its teratogenic mechanisms are not fully understood. The alcohol form of vitamin A (retinol/ROL) can be oxidized to all-trans-retinoic acid (RA), which plays a critical role in stem cell differentiation and development. Using an embryonic stem cell (ESC) model to analyze EtOH's effects on differentiation, we show here that EtOH and acetaldehyde, but not acetate, increase differentiation-associated mRNA levels, and that EtOH decreases pluripotency-related mRNAs. Using reporter assays, ChIP assays, and retinoic acid receptor-γ (RARγ) knockout ESC lines generated by CRISPR/Cas9 and homologous recombination, we demonstrate that EtOH signals via RARγ binding to RA response elements (RAREs) in differentiation-associated gene promoters or enhancers. We also report that EtOH-mediated increases in homeobox A1 (Hoxa1) and cytochrome P450 family 26 subfamily A member 1 (Cyp26a1) transcripts, direct RA target genes, require the expression of the RA-synthesizing enzyme, aldehyde dehydrogenase 1 family member A2 (Aldh1a2), suggesting that EtOH-mediated induction of Hoxa1 and Cyp26a1 requires ROL from the serum. As shown with CRISPR/Cas9 knockout lines, the retinol dehydrogenase gene Rdh10 and a functional RARE in the ROL transporter stimulated by retinoic acid 6 (Stra6) gene are required for EtOH induction of Hoxa1 and Cyp26a1 We conclude that EtOH stimulates stem cell differentiation by increasing the influx and metabolism of ROL for downstream RARγ-dependent transcription. In stem cells, EtOH may shift cell fate decisions to alter developmental outcomes by increasing endogenous ROL/RA signaling via increased Stra6 expression and ROL oxidation.

From abortion-inducing medications to Zika Virus Syndrome: 27 years experience of the First Teratogen Information Service in Latin America.

In 1990, the first Teratogen Information Service in Brazil (SIAT) was implemented in the Medical Genetics Service at Hospital de Clinicas de Porto Alegre. SIAT is a free-to-use information service both to health professionals and the general population, especially to women who are pregnant or planning pregnancy. The main objective of this paper is to present the activities of SIAT in its initial years (1990-2006), compared to those in the last decade (2007-2017). In addition we review the scientific contribution of SIAT in the field of human teratogenesis. Since 1990, SIAT received 10,533 calls. Use of medications were the main reason for concern, accounting for 74% of all questions, followed by other chemical exposures (occupational, cosmetics, environmental), and maternal infectious diseases. Among its main contributions to scientific knowledge was the collaboration for the identification of two new human teratogens: misoprostol in the 1990s and Zika virus in 2015/16. In conclusion, SIAT is still evolving, as is the Medical Genetics Service that hosts it. Through its 27 years of existence more than 300 undergraduate and graduate students have rotated at SIAT. Presently, SIAT is expanding the research to experimental teratogenesis and to investigation of molecular mechanisms of teratogens.

Teratogenicity of valproic acid and its constitutional isomer, amide derivative valnoctamide in mice.

The anticonvulsant valproic acid (VPA) has a known teratogenic effect capable of inducing major congenital malformations and developmental disorders. A comparative teratogenicity study of VPA and its analog valnoctamide (VCD), which is a new generation candidate antiepileptic drug, was carried out using Swiss Vancouver (SWV) mice. Pregnant SWV dams were treated with either a single intraperitoneal injection of VPA (1.8 and 2.7 mmol/kg), VCD (1.8 and 2.7 mmol/kg), or vehicle on E8:12 (gestational day:hour). The numbers of implantation and resorption, viable and dead fetuses, and the presence of gross fetal visceral and skeletal abnormalities were determined (E18). Real-time Polymerase chain reaction (RT-PCR) arrays were used to analyze the expression of 84 genes related to the processes of neurogenesis and neural stem cell differentiation. Significant decreases in pregnancy weight gain and the number of live fetuses were observed when VPA was administered at the high dose, whereas the percentage of exencephalic fetuses was significantly increased in VPA treated compared with an equivalent VCD dosage group. There was a dose-related increase in visceral defects in the VPA-exposed fetuses. Missing skull bones and fused vertebrae in fetuses occurred at the high dose of VPA. Three genes (Mtap2, Bmp8b, and Stat3) were significantly upregulated and one (Heyl) was downregulated in samples from VPA-treated dams. The study demonstrates that the teratogenicity of VPA was significantly greater than that of an equimolar dose of VCD. Four genes (Mtap2, Bmp8b, Stat3, and Heyl) represent candidate target genes for the underlying teratogenic mechanism responsible for VPA-induced malformations.

A new target for thalidomide.

One mechanism of thalidomide teratogenicity involves binding to the CUL4–CRBN E3 ubiquitin ligase complex, which then mediates the degradation of transcription factors. New studies reveal that species-specific variants of the transcription factor SALL4 are differentially ubiquitinated and degraded via the thalidomide-bound complex.

Concentration‐Dependent Actions of Piperidine Alkaloids on the Inhibition of Fetal Movement in Day 40 Pregnant Goats and Comparison to Cell‐Based Models.

Anabasine and anabaseine are potent and effective agonists at nicotinic acetylcholine receptors (nAChR). Anabasine in livestock species is teratogenic and has been shown to cause developmental defects that include arthrogyrposis, kyposis, lordosis, scoliosis, and torticollis. We have postulated that these fetal defects are due to the complete and sustained inhibition of fetal movement. The purpose of this research was to determine if cell‐based predictions of teratogenicity from TE‐671 cell experiments translate to inhibition of fetal movement in a day 40 pregnant goat model. We hypothesized that anabasine, anabaseine, epibatidine, and DMPP which are potent and effective agonists atfetal muscle‐type nAChR expressed by TE‐671 cells, would be effective at completely inhibiting fetal movement in a goat model the putative mechanism of teratogenicity in livestock species. Pregnant goats were I.V. dosed with anabasine, anabaseine, epibatidine, DMPP, or saline control on gestation day 40 and the number of fetal movements were measured by ultrasound periodically for 8 hours. The experiment was designed to only briefly inhibit fetal movement(&lt; 3 h) and as a result, no terata were observed in any of the kids from the pregnant does dosed with any of the compounds in this study. Anabasine, at a dose of 0.8 mg/kg, completely inhibited fetal movement for 1.5 hours after dosing, and its actions were dose‐dependent with an IC50 value of 0.1 mg/kg. Anabaseine, epibatidine, and DMPP did not completely inhibit fetal movement in day 40 pregnant goats. The results from this experiment suggest that while experiments with TE‐671 cells provide valuable information and predictions of the actions of plant alkaloids on fetal movement, in vivo experiments are still required in order to determine the ability of an alkaloid to inhibit fetal movement in livestock species and to predict teratogenic potential.Support or Funding InformationFunding provided by USDA ARSThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Ketamine Modulates Zic5 Expression via the Notch Signaling Pathway in Neural Crest Induction.

Ketamine is a potent dissociative anesthetic and the most commonly used illicit drug. Many addicts are women at childbearing age. Although ketamine has been extensively studied as a clinical anesthetic, its effects on embryonic development are poorly understood. Here, we applied the Xenopus model to study the effects of ketamine on development. We found that exposure to ketamine from pre-gastrulation (stage 7) to early neural plate (stage 13.5) resulted in disruption of neural crest (NC) derivatives. Ketamine exposure did not affect mesoderm development as indicated by the normal expression of Chordin, Xbra, Wnt8, and Fgf8. However, ketamine treatment significantly inhibited Zic5 and Slug expression at early neural plate stage. Overexpression of Zic5 rescued ketamine-induced Slug inhibition, suggesting the blockage of NC induction was mediated by Zic5. Furthermore, we found Notch signaling was altered by ketamine. Ketamine inhibited the expression of Notch targeted genes including Hes5.2a, Hes5.2b, and ESR1 and ketamine-treated embryos exhibited Notch-deficient somite phenotypes. A 15 bp core binding element upstream of Zic5 was induced by Notch signaling and caused transcriptional activation. These results demonstrated that Zic5 works as a downstream target gene of Notch signaling in Xenopus NC induction. Our study provides a novel teratogenic mechanism whereby ketamine disrupts NC induction via targeting a Notch-Zic5 signaling pathway.

Zika Virus Fatally Infects Wild Type Neonatal Mice and Replicates in Central Nervous System.

Zika virus (ZIKV) has been defined as a teratogenic pathogen behind the increased number of cases of microcephaly in French Polynesia, Brazil, Puerto Rico, and other South American countries. Experimental studies using animal models have achieved tremendous insight into understanding the viral pathogenesis, transmission, teratogenic mechanisms, and virus–host interactions. However, the animals used in published investigations are mostly interferon (IFN)-compromised, either genetically or via antibody treatment. Herein, we studied ZIKV infection in IFN-competent mice using African (MR766) and Asian strains (PRVABC59 and SZ-WIV01). After testing four different species of mice, we found that BALB/c neonatal mice were resistant to ZIKV infection, that Kunming, ICR and C57BL/6 neonatal mice were fatally susceptible to ZIKV infection, and that the fatality of C57BL/6 neonates from 1 to 3 days old were in a viral dose-dependent manner. The size and weight of the brain were significantly reduced, and the ZIKV-infected mice showed neuronal symptoms such as hind-limb paralysis, tremor, and poor balance during walking. Pathologic and immunofluorescent experiments revealed that ZIKV infected different areas of the central nervous system (CNS) including gray matter, hippocampus, cerebral cortex, and spinal cord, but not olfactory bulb. Interestingly, ZIKV replicated in multiple organs and resulted in pathogenesis in liver and testis, implying that ZIKV infection may engender a high health risk in neonates by postnatal infection. In summary, we investigated ZIKV pathogenesis using an animal model that is not IFN-compromised.