51
|
Martin LJ, Machado AF, Loza MA, Mao GE, Lee GS, Hovland DN, Cantor RM, Collins MD. Effect of arsenite, maternal age, and embryonic sex on spina bifida, exencephaly, and resorption rates in the splotch mouse. BIRTH DEFECTS RESEARCH. PART A, CLINICAL AND MOLECULAR TERATOLOGY 2003; 67:231-9. [PMID: 12854658 DOI: 10.1002/bdra.10006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND This study examines interactions of a mutation in Pax3, embryonic sex, advanced maternal age, and arsenite exposure in the splotch (Sp) mouse model, with the aim of describing gene-environment interactions for neural tube defects and embryonic lethality. METHODS Splotch heterozygous C57BL/6J mice were crossed to produce offspring of three genotypes with a common maternal genotype that were exposed to either sodium arsenite on gestational day (GD) 8.0, or advanced maternal age (dams older than 12 months). Embryos were extracted on GD 12 and genotyped for both Pax3 and sex. RESULTS Arsenite treatment was a significant contributor to both exencephaly and spina bifida. Advanced maternal age resulted in a high exencephaly rate in Sp/Sp female embryos (but not other genotypes) and a high overall resorption rate. Arsenite treatment and advanced maternal age resulted in elevated sex ratios (male:female) for heterozygous and wild-type embryos. The sex ratio was highest for wild-type embryos and was lowered as the number of mutant Pax3 alleles increased. The sex ratio was not significantly different from 1.0 for splotch homozygotes. Control litters had spina bifida rates that were 95% in homozygous, 6% in heterozygous, and 0% in wild-type embryos. CONCLUSIONS If arsenite produces exencephaly by inactivating the Pax3 protein, then the fact that the exencephaly rate was increased in Sp/Sp embryos with no functional Pax3 indicates that arsenite may either induce this defect through additional pathways, or may alter the response via modifier genes. Genetic and environmental factors contributed to the determination of murine sex ratios, with female embryos being more susceptible to loss.
Collapse
|
52
|
Gillick J, Mooney E, Giles S, Bannigan J, Puri P. Notochord anomalies in the adriamycin rat model: A morphologic and molecular basis for the VACTERL association. J Pediatr Surg 2003; 38:469-73; discussion 469-73. [PMID: 12632369 DOI: 10.1053/jpsu.2003.50081] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND/PURPOSE The Adriamycin rat model (ARM) is a reliable model of the VACTERL association. The notochord is structurally abnormal in the region of the foregut, midgut, and hindgut in the ARM. The authors hypothesised that notochord anomalies allow ectopic expression of molecular signals in the developing embryo and thus lead to VACTERL malformations. This study was designed to investigate this hypothesis. METHODS Adriamycin (1.75 mg/kg) was administered intraperitoneally to pregnant rats on days 7, 8, and 9 of gestation. Control animals were given saline. Embryos were recovered on gestational days 10.5 to 14 at (1/2)-day intervals and at full term. The first group of embryos were embedded in resin, and sagittal sections stained with Toluidine blue were studied for morphologic abnormalities. The second group of embryos were examined using in situ hybridization for the expression of Sonic Hedgehog (Shh), a patterning gene implicated in the etiology of the VACTERL association. RESULTS Twenty-seven of the 28 (96.4%) full-term embryos showed VACTERL anomalies. Forty-five of the 50 (90%) experimental embryos (gestational days 10.5 to 14) showed notochord abnormalities. Abnormal ventral branches from the notochord toward the gut were a commonly observed abnormality. These were seen to impinge on the developing foregut, midgut, dorsal aorta, and kidney. In situ hybridization for Shh showed that these branches from the notochord expressed Shh in 66.6% of experimental embryos. This abnormal Shh expression was not seen in the control embryos. CONCLUSIONS Adriamycin diffusely induces altered notochord morphology in the rat embryo. The abnormal notochord morphology may allow ectopic expression of Sonic Hedgehog, and, thus, contribute to the malformations found in the VACTERL association.
Collapse
MESH Headings
- Abnormalities, Drug-Induced/etiology
- Abnormalities, Drug-Induced/genetics
- Abnormalities, Drug-Induced/metabolism
- Abnormalities, Drug-Induced/pathology
- Abnormalities, Multiple/chemically induced
- Abnormalities, Multiple/genetics
- Abnormalities, Multiple/metabolism
- Abnormalities, Multiple/pathology
- Animals
- Disease Models, Animal
- Doxorubicin/toxicity
- Esophageal Atresia/chemically induced
- Esophageal Atresia/embryology
- Esophageal Atresia/genetics
- Female
- Fetal Proteins/biosynthesis
- Fetal Proteins/genetics
- Fetal Proteins/physiology
- Gene Expression Regulation, Developmental/drug effects
- Gestational Age
- Hedgehog Proteins
- Intestines/embryology
- Morphogenesis/drug effects
- Notochord/abnormalities
- Notochord/drug effects
- Pregnancy
- Rats
- Rats, Wistar
- Tracheoesophageal Fistula/chemically induced
- Tracheoesophageal Fistula/embryology
- Tracheoesophageal Fistula/genetics
- Trans-Activators/biosynthesis
- Trans-Activators/genetics
- Trans-Activators/physiology
Collapse
|
53
|
Spilde TL, Bhatia AM, Marosky JK, Preuett B, Kobayashi H, Hembree MJ, Prasadan K, Daume E, Snyder CL, Gittes GK. Fibroblast growth factor signaling in the developing tracheoesophageal fistula. J Pediatr Surg 2003; 38:474-7; discussion 474-7. [PMID: 12632370 DOI: 10.1053/jpsu.2003.50082] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND/PURPOSE The Adriamycin-induced rat model of esophageal atresia and tracheoesophageal fistula (EA/TEF) provides a reliable system for the study of EA/TEF pathogenesis. The authors previously hypothesized that faulty branching lung morphogenesis pathways were a critical component of its pathogenesis. The authors have found evidence for faulty fibroblast growth factor (FGF) signaling related to epithelial-mesenchymal interactions in the fistula tract. To better define FGF signaling, the differential expression of FGF ligands and their receptors between lung, fistula tract, and esophagus are described. METHODS Time-dated pregnant, Sprague-Dawley rats were injected with Adriamycin (2 mg/kg intraperitoneally) on days 6 through 9 of gestation. Tissues were processed for histology and reverse transcriptase polymerase chain reaction. FGF-1, -7 and -10 were measured from whole lung, fistula tract, and esophagus of TEF or normal embryos. Expression of FGF2RIIIb and FGF2RIIIc receptors was measured in isolated epithelium and mesenchyme of lung and fistula tract of TEF embryos as well as lung and esophagus from normal controls. RESULTS FGF-1 mRNA was present in the fistula tract and normal and Adriamycin-exposed lung but absent from whole esophagus. Interestingly, FGF-7 mRNA was present only in normal lung. FGF-10 was present in all tissues examined. FGF2RIIIb mRNA was absent in fistula mesenchyme but present in all other tissues examined. However, the splice variant FGF2RIIIc mRNA was present in all tissues examined. CONCLUSIONS These findings support defective FGF signaling in the rat model of EA/TEF. Absence of FGF-7 mRNA in Adriamycin-exposed tissues suggests the primary effect of Adriamycin may be to inhibit FGF-7 expression. Moreover, absence of FGF2RIIIb in fistula mesenchyme may be caused by loss of positive feedback from FGF-7, its normal obligate ligand. Understanding these specific defects in FGF signaling may provide insight into faulty mechanisms of EA/TEF.
Collapse
MESH Headings
- Abnormalities, Drug-Induced/etiology
- Abnormalities, Drug-Induced/genetics
- Abnormalities, Drug-Induced/metabolism
- Abnormalities, Drug-Induced/pathology
- Abnormalities, Multiple/chemically induced
- Abnormalities, Multiple/genetics
- Abnormalities, Multiple/metabolism
- Abnormalities, Multiple/pathology
- Animals
- Disease Models, Animal
- Doxorubicin/toxicity
- Epithelium/metabolism
- Esophageal Atresia/chemically induced
- Esophageal Atresia/embryology
- Esophageal Atresia/genetics
- Esophagus/embryology
- Esophagus/metabolism
- Female
- Fetal Proteins/biosynthesis
- Fetal Proteins/genetics
- Fetal Proteins/physiology
- Fibroblast Growth Factor 7
- Fibroblast Growth Factors/biosynthesis
- Fibroblast Growth Factors/deficiency
- Fibroblast Growth Factors/genetics
- Fibroblast Growth Factors/physiology
- Gene Expression Regulation, Developmental/drug effects
- Lung/embryology
- Lung/metabolism
- Mesoderm/chemistry
- Morphogenesis/drug effects
- Pregnancy
- Rats
- Rats, Sprague-Dawley
- Receptor, Fibroblast Growth Factor, Type 2
- Receptors, Fibroblast Growth Factor/biosynthesis
- Receptors, Fibroblast Growth Factor/deficiency
- Receptors, Fibroblast Growth Factor/genetics
- Receptors, Fibroblast Growth Factor/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Trachea/embryology
- Trachea/metabolism
- Tracheoesophageal Fistula/chemically induced
- Tracheoesophageal Fistula/embryology
- Tracheoesophageal Fistula/genetics
Collapse
|
54
|
Ozkinay F, Cogulu O, Gunduz C, Yilmaz D, Kultursay N. Valproic acid and lamotrigine treatment during pregnancy. The risk of chromosomal abnormality. Mutat Res 2003; 534:197-9. [PMID: 12504768 DOI: 10.1016/s1383-5718(02)00254-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A baby born to an epileptic mother had dysmorphological features associated with 47,XXX karyotype. The mother had been treated with valproic acid (1800mg per day) and lamotrigine (100mg per day) throughout pregnancy. Dysmorphological features detected in baby were intrauterine growth retardation, hypertelorism, flattened nasal bridge, low set malformed auriculas, micrognathia, very small an bow-shaped mouth with thin upper lip, cleft palate, arachnodactyly, camptodactyly, secundum atrial septal defect, bilateral hammer toes and decreased creases on the soles. At 6 months old she showed motor retardation. The molecular analysis of parents revealed that extra X chromosome was inherited from the mother. In this case whether the dysmorphological features and 47,XXX karyotype were caused by lamotrigine and valproic acid treatment during pregnancy or coincidence is in question.
Collapse
|
55
|
Mirkes P, McClure ME, Heindel JJ, Sander M. Developmental toxicology in the 21st century: multidisciplinary approaches using model organisms and genomics. BIRTH DEFECTS RESEARCH. PART A, CLINICAL AND MOLECULAR TERATOLOGY 2003; 67:21-34. [PMID: 12749381 DOI: 10.1002/bdra.10024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
56
|
Abbott BD, Buckalew AR, DeVito MJ, Ross D, Bryant PL, Schmid JE. EGF and TGF-alpha expression influence the developmental toxicity of TCDD: dose response and AhR phenotype in EGF, TGF-alpha, and EGF + TGF-alpha knockout mice. Toxicol Sci 2003; 71:84-95. [PMID: 12520078 DOI: 10.1093/toxsci/71.1.84] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces cleft palate (CP) and hydronephrosis (HN) in mice. The etiology of these defects involves hyperproliferation of epithelial cells of the secondary palatal shelf and ureter, respectively. These effects correlate with altered expression of the epidermal growth factor receptor (EGFR), epidermal growth factor (EGF), and transforming growth factor-alpha (TGF-alpha). In this study, the developmental toxicity of TCDD was examined in EGF, TGF-alpha, and double EGF + TGF-alpha knockout (-/-) and wild type (WT) mice. The influence of background genetics in responsiveness to TCDD was examined using liver 7-ethoxyresorufin-O-deethylase (EROD) activity. Animals were dosed by gavage with 0, 0.2, 1, 5, 24, 50, 100, or 150 micro g TCDD/kg (5 ml/kg) body weight on gestation day 12. The mixed genetic background of WT, EGF (-/-), and EGF + TGF-alpha (-/-) made these mice less responsive to TCDD relative to C57BL/6J and TGF-alpha (-/-), which have a C57BL background. These results show that EGF and TGF-alpha are not required for response to TCDD; however, the specific ligand available to bind EGFR affects the responsiveness to TCDD. EGF (-/-) mice are less responsive for CP, but more sensitive to HN. TGF-alpha (-/-) mice were similar to WT in sensitivity for induction of CP and HN. The responses of EGF + TGF-alpha (-/-) mice were like the WT except at higher doses where sensitivity to CP increased, suggesting that the responses may be mediated by alternative ligands for EGFR that are not functional equivalents of EGF or TGF-alpha. In conclusion, the EGFR pathway is mechanistically important in responses of the embryo to TCDD. Specific ligands confer sensitivity or resistance that are target tissue-dependent.
Collapse
|
57
|
Docterman KE, Smith SM. Of meis and men: lessons from a microarray study of teratogen action. TERATOLOGY 2002; 66:217-23. [PMID: 12397629 DOI: 10.1002/tera.10110] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|
58
|
Winn LM, Wells PG. Evidence for Ras-dependent signal transduction in phenytoin teratogenicity. Toxicol Appl Pharmacol 2002; 184:144-52. [PMID: 12460742 DOI: 10.1006/taap.2002.9504] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reactive oxygen species (ROS) can transduce intracellular signals or damage macromolecules, including mutational activation of the K-ras oncogene, particularly in A/J mice, which are reported to be highly sensitive to the ROS-initiating teratogen phenytoin. Here, we determined in embryo culture whether the Ras pathway mediated phenytoin embryopathy at the protein or gene level. Embryos from pregnant inbred A/J dams and outbred CD-1 dams were cultured with a therapeutic concentration of phenytoin, with or without alpha-hydroxyfarnesylphosphonic acid, an inhibitor of the enzyme farnesyl-protein transferase, which is required for posttranslational Ras activation. A/J and CD-1 embryos were similarly susceptible to phenytoin embryopathies, with reductions in anterior neuropore closure, turning, yolk sac diameter, and somite development (p < 0.05). The farnesyl-protein transferase inhibitor blocked phenytoin embryotoxicity in A/J embryos for all parameters except yolk sac diameter (p < 0.05) and completely blocked embryotoxicity in CD-1 embryos (p < 0.05). Embryonic DNA did not show phenytoin-initiated mutations in codon 12 of the K-ras gene in either A/J or CD-1 embryos, but phenytoin substantially increased the levels of GTP-bound Ras in both CD-1 and A/J embryos. These results provide the first direct evidence that Ras proteins may be involved in the teratogenicity of phenytoin, likely via a mechanism other than mutational activation.
Collapse
|
59
|
Strömland K, Philipson E, Andersson Grönlund M. Offspring of male and female parents with thalidomide embryopathy: birth defects and functional anomalies. TERATOLOGY 2002; 66:115-21. [PMID: 12210472 DOI: 10.1002/tera.10083] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND The aim of the study was to evaluate congenital malformations and functional anomalies in the offspring of Swedish parents with thalidomide embryopathy (TE). METHODS Sixty-four children (29 girls, 35 boys) with ages ranging from 0-18 years, born to 34 Swedish parents (14 women, 20 men) with TE, were studied. Data on malformations and dysfunction were collected from medical records at maternity and child healthcare units, delivery units, hospitals, outpatient clinics and schools. RESULTS Five children had both a mother and father with TE, 23 had a mother suffering from TE, and in 36 children the father had TE. One girl had a major malformation consisting of pulmonary stenosis, and single cases of minor physical features and positional deformities were observed. One boy had autism. Four children were born preterm, all to a TE mother. One child died within 24 hr after birth. Seven spontaneous abortions were registered, five of them in TE mothers. The cesarian section rate was 39% among the TE mothers, compared to 14% among the non-TE mothers. CONCLUSIONS Malformations or functional anomalies similar to those typical for TE were not found in this group of children born to Swedish parents with TE. Cesarian sections were more frequently performed in TE mothers, partly because of pelvic and uterine malformations.
Collapse
|
60
|
Finnell RH, Waes JGV, Eudy JD, Rosenquist TH. Molecular basis of environmentally induced birth defects. Annu Rev Pharmacol Toxicol 2002; 42:181-208. [PMID: 11807170 DOI: 10.1146/annurev.pharmtox.42.083001.110955] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Exposure of the developing conceptus to selected environmental agents can lead to deleterious and often times lethal birth defects. These malformations result in serious emotional and financial consequences to families and societies worldwide. As we continue to progress technologically, we face challenges from the introduction of new pharmacological agents and chemical compounds into the environment. This results in a concomitant need to more fully understand the relationship between in utero exposure to environmental teratogens and the risk of congenital malformations. The goal of this review is to provide a current perspective of the major concepts related to the molecular basis of environmentally induced birth defects. Starting with a discussion of commonly occurring birth defects, we consider important fundamental facets of embryonic development, teratology, and gene-environment interactions. The review then summarizes our current understanding of the molecular mechanisms involved in selected birth defects following exposure to pharmacological compounds, including thalidomide, retinoids, and valproic acid. Understanding these signaling pathways may lead to the development of safer pharmaceutical compounds and a reduction in the number of infants born with preventable birth defects.
Collapse
|
61
|
O'Hara MF, Charlap JH, Craig RC, Knudsen TB. Mitochondrial transduction of ocular teratogenesis during methylmercury exposure. TERATOLOGY 2002; 65:131-44. [PMID: 11877777 DOI: 10.1002/tera.10028] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND The purpose of the present study was to investigate the correlation between MeHg developmental toxicity and mitochondrial 16S ribosomal RNA (16S rRNA) expression in the embryonic forebrain and pharmacological intervention with PK11195, a ligand for the mitochondrial peripheral-type benzodiazepine receptor (Bzrp). METHODS Pregnant CD-1 mice were dosed with methylmercury (II) chloride (MeHg) with or without 4 mg/kg PK11195 on Day 9 of gestation. Fetuses were examined on Day 9 (RT-PCR), Day 15 (histology), and Day 17 (teratology). RESULTS MeHg (10 mg/kg) induced microcephaly, microphthalmia and cleft palate. The mean incidences of malformed fetuses were 47.7% with MeHg (P < 0.001) and 19.2% with PK11195 co-treatment (P < 0.01 for rescue). Cleft palates were 12.8% and 1.5%, respectively. An estimate of neurocranial circumference revealed a small (5%) but highly significant (P < 0.001) reduction that was rescued in a subset of co-treated fetuses (P < 0.05). RT-PCR analysis of the Day 9 forebrain revealed inhibition of 16S rRNA expression 3.0 hr after 5 mg/kg MeHg exposure (P < 0.001). This effect was rescued with PK11195 (P < 0.001). Preliminary findings revealed a similar response-rescue in cultured embryos exposed to 1 microM Hg(II) when exogenous 5-aminolevulinic acid (ALA) was added. Protoporphyrin-IX (PP9), the penultimate precursor to heme and an endogenous ligand of the Bzrp, increased in a manner that was ALA-dependent and PK11195-sensitive. CONCLUSION At least some teratological effects of Hg appear linked with late steps in the heme biosynthesis pathway through the Bzrp. PK11195, a ligand for these mitochondrial receptors, significantly lessens the risk of microphthalmia, microcephaly, and cleft palate in Hg-poisoned embryos.
Collapse
|
62
|
Vrijheid M, Dolk H, Armstrong B, Abramsky L, Bianchi F, Fazarinc I, Garne E, Ide R, Nelen V, Robert E, Scott JES, Stone D, Tenconi R. Chromosomal congenital anomalies and residence near hazardous waste landfill sites. Lancet 2002; 359:320-2. [PMID: 11830202 DOI: 10.1016/s0140-6736(02)07531-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Previous findings of the EUROHAZCON study showed a 33% increase in risk of non-chromosomal anomalies near hazardous waste landfill sites. Here, we studied 245 cases of chromosomal anomalies and 2412 controls who lived near 23 such sites in Europe. After adjustment for confounding by maternal age and socioeconomic status, we noted a higher risk of chromosomal anomalies in people who lived close to sites (0-3 km) than in those who lived further away (3-7 km; odds ratio 1.41, 95% CI 1.00-1.99). Our results suggest an increase in risk of chromosomal anomalies similar to that found for non-chromosomal anomalies.
Collapse
|
63
|
Nasrallah I, Golden JA. Brain, eye, and face defects as a result of ectopic localization of Sonic hedgehog protein in the developing rostral neural tube. TERATOLOGY 2001; 64:107-13. [PMID: 11460262 DOI: 10.1002/tera.1052] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Normal development of the face, eyes, and brain requires the coordinated expression of many genes. One gene that has been implicated in the development of each of these structures encodes the secreted protein, Sonic hedgehog (Shh). During central nervous system development, Shh is required for ventral specification along the entire neural axis. To further explore the role of Shh in chick brain and craniofacial development, we overexpressed Shh in the developing rostral neural tube METHODS In order to determine if Shh is sufficient to ventralize the forebrain, we localized ectopically recombinant Shh protein to the rostral neural tube of chick embryos. The resulting embryos were evaluated morphologically and by assaying gene expression. RESULTS Disruption in normal gene expression patterns was observed with a reduction or loss in expression of genes normally expressed in the dorsal forebrain (wnt-3a, wnt-4, and Pax-6) and expansion of ventrally expressed genes dorsally (HNF-3beta, Ptc). In addition to the genetic alterations observed in the neural tube, a craniofacial phenotype characterized by a reduction in many cranial neural crest-derived structures was observed. The eyes of Shh-treated embryos were also malformed. They were small with expansion of the retinal pigmented epithelium, enlarged optic stalks, and a reduction of neural retina. DISCUSSION The ectopic localization of recombinant Shh protein in the rostral neural tube resulted in severe craniofacial anomalies and alterations of gene expression predicted by other studies. The system employed appears to be a model for studying the embryogenesis of malformations that involve the brain, eyes, and face.
Collapse
|
64
|
Machado AF, Martin LJ, Collins MD. Pax3 and the splotch mutations: structure, function, and relationship to teratogenesis, including gene-chemical interactions. Curr Pharm Des 2001; 7:751-85. [PMID: 11375778 DOI: 10.2174/1381612013397726] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The current review focuses on the malformations resulting from mutations in Pax3 and the interactions of Pax3 mutations with chemically induced teratogenesis, as well as other mutant genes or genetic strains, as a paradigm to illustrate the connections among genetics, protein function, and teratology. Splotch mice result from various mutations involving Pax3, and Waardenburg syndromes I and III in the human are due to mutations in PAX3. The human and murine phenotype/genotype correlations are thus compared and contrasted. The role of Pax3 in normal development, as well as the regulation of Pax3 expression and DNA binding, are also addressed on the premise that a mechanistic understanding of normal developmental processes is prerequisite to full comprehension of the mechanisms by which abnormal development is induced. Pax3 encodes a transcription factor involved in myogenesis, melanogenesis and neurogenesis, as well as regulating genes that may be involved in other cellular processes. The primary goal of this review is to examine the role of a single important developmental gene in the interaction of genetics and abnormal development.
Collapse
|
65
|
Arnon J, Meirow D, Lewis-Roness H, Ornoy A. Genetic and teratogenic effects of cancer treatments on gametes and embryos. Hum Reprod Update 2001; 7:394-403. [PMID: 11476352 DOI: 10.1093/humupd/7.4.394] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Male and female germ cells vary in their sensitivity to the mutagenic effects of chemotherapy and radiotherapy, depending on their stage of maturation and the agent used. Although sperm DNA damage exists following treatment, no increase in genetic defects or congenital malformations was detected among children conceived to parents who have previously undergone chemotherapy or radiotherapy. The use of assisted reproductive technologies and micromanipulation techniques might increase this risk; hence caution should be exercised. In female cancer patients, miscarriage and congenital malformations are not increased following chemotherapy. However, when IVF and embryo cryopreservation is practised between or shortly after treatment, possible genetic risks to the growing oocytes exist, and hence the babies should be screened. During pregnancy, the potential teratogenic effects of chemotherapy influence the choice and timing of therapy. Termination is usually recommended in the first trimester. Second- and third-trimester exposure does not usually increase the teratogenic risk and cognitive development, but it may increase the risk of poor obstetric outcome and fetal myelosuppression. During the first two weeks after fertilization of the embryo, radiation is lethal but not teratogenic. High doses of radiation during pregnancy induce anomalies, impaired growth and mental retardation, and there may be an increased risk of childhood leukaemia and other tumours in the offspring.
Collapse
|
66
|
Bíla V, Kren V, Liska F. The influence of the genetic background on the interaction of retinoic acid with Lx mutation of the rat. Folia Biol (Praha) 2001; 46:264-72. [PMID: 11140860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
The teratogenic effect of RA was found to be significantly influenced both by genetic background and by the genotype of malformation mutation Lx. The presence of the Lx mutation and BN genetic background strongly increases the teratogenic effect of RA. On the contrary, the SHR genetic background was shown to protect foetuses from RA teratogenic affliction. Recombinant inbred strain BXH2 is endowed with a specific combination of BN and SHR genes, and following RA administration it exhibits the same embryolethal effect as the BN genetic background alone. Without the Lx mutation there was no effect of RA on hind limbs in SHR/SHR or SHR/BN progeny whilst there was a significantly higher occurence of oligodactyly in SHR/BN on forelimbs as compared to SHR/SHR (92.2% vs 11.5%). In +/Lx progeny, forelimbs were significantly more afflicted with oligodactyly in SHR/BN +/Lx in comparison with both SHR/SHR and SHR/BXH2 foetuses, which indicates that BN modifiers responsible for oligodactyly were not passed to the BXH2 strain. On the contrary, hind limbs of SHR/BXH2, +/Lx progeny exhibited the highest affliction (62% of polydactyly and/or oligodactyly). In homozygous Lx/Lx progeny, polydactyly prevailed in forelimbs of SHR/BXH2 following RA administration, whilst in BN/BN progeny oligodactyly was the most frequent affliction. On the hind limbs, the highest reduction of toe number after RA treatment was connected with BN modifiers. The polymorphism of normal morphogenetic factors was shown to be responsible not only for Lx. phenotypic manifestation, but also for the variability in the response to RA teratogenic action.
Collapse
MESH Headings
- Abnormalities, Drug-Induced/genetics
- Abnormalities, Multiple/chemically induced
- Abnormalities, Multiple/embryology
- Abnormalities, Multiple/genetics
- Alleles
- Animals
- Animals, Congenic
- Crosses, Genetic
- Embryonic and Fetal Development/genetics
- Face/abnormalities
- Face/embryology
- Female
- Forelimb/abnormalities
- Forelimb/embryology
- Genetic Predisposition to Disease
- Genotype
- Gestational Age
- Hindlimb/abnormalities
- Hindlimb/embryology
- Male
- Morphogenesis/genetics
- Polydactyly/genetics
- Rats
- Rats, Inbred BN/genetics
- Rats, Inbred SHR/genetics
- Rats, Mutant Strains/embryology
- Rats, Mutant Strains/genetics
- Syndrome
- Tail/abnormalities
- Tail/embryology
- Teratogens/toxicity
- Toes/abnormalities
- Toes/embryology
- Tretinoin/toxicity
Collapse
|
67
|
Abstract
Reciprocal outcrosses and backcrosses were made between strains of mice with different susceptibilities to valproic acid (VPA) teratogenicity. Relatively resistant C57BL/6J (C) and more susceptible SWV (S) strains of mice produced F1 hybrids in which the female parent was C and the male parent was S (CS-F1) as well as the reciprocal with S dams and C sires (SC-F1). Each was backcrossed to each strain, producing 8 types of backcross matings: CS x C, SC x C, CS x S, SC x S; C x CS, C x SC, S x CS, S x SC (for all matings dams are listed first). At 8d:12 +/- 5h of gestation, a teratogenic dose, 600 mg/kg, of aqueous VPA was injected ip into the dams. Fetuses were examined on gestation day (gd) 18 for abnormality, mortality, litter size, and weight. Genomic imprinting (imprinting) is a phenomenon at least in part involving hyper- or hypomethylation of bases in DNA, which is believed to determine whether or not the imprinted gene will be expressed. Imprinting has been reported to occur differentially in the male and female for a number of gene loci. Thus, in crosses between strains with differing susceptibility to VPA, if imprinting is occurring, the susceptibility of a fetus might be predicted to be disproportionately influenced by susceptibility of its grandparents. Significant differences in frequency (%) of occurrence of exencephaly in progeny of all backcrosses with F1 dams consistent with those expected for imprinting were found in the present study (CS-F1x C = 21.8 +/- 3.9%, SC-F1x C = 10.8 +/- 3.2%, P < 0.03; CS-F1x S = 14.8 +/- 3.1%, SC-F1x S = 6.3 +/- 2.3%, P < 0.03). SWV dams revealed the same pattern (S x SC-F1 = 50.0 +/- 8.3%, S x CS-F1 = 37.1 +/- 4.7%, P < 0.04). Differences in prenatal mortality also consistent with genomic imprinting occurred in backcrosses with pure-line SWV dams (S x SC = 64.4 +/- 8.0%, S x CS = 30.5 +/- 4.5%, P < 0.001). Fetal weight was reduced in a manner consistent with imprinting in backcrosses involving SWV (S x SC = 0.50 +/- 0.18 g, S x CS = 0.96 +/- 0.05, P < 0.01). Three of four of the parameters investigated showed differences in some of the backcrosses of reciprocal F1's consistent with those expected if genomic imprinting were occurring.
Collapse
|
68
|
Sharova L, Sura P, Smith BJ, Gogal RM, Sharov AA, Ward DL, Holladay SD. Nonspecific stimulation of the maternal immune system. II. Effects on gene expression in the fetus. TERATOLOGY 2000; 62:420-8. [PMID: 11091364 DOI: 10.1002/1096-9926(200012)62:6<420::aid-tera9>3.0.co;2-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Maternal immune stimulation reduces malformations caused by chemical teratogens. Mechanisms for this effect are not known. Altered expression of regulatory molecules (e.g., transforming growth factor [TGF-beta], tumor necrosis factor-alpha [TNF-alpha]) has been reported in fetuses from immunostimulated mice, which may affect gene expression. Expression of selected genes that function to control proliferation, differentiation, or apoptosis was evaluated in chemical-exposed fetuses, with or without maternal immunostimulation. METHODS Ethyl carbamate (urethane) was given to pregnant ICR mice on day 10 of gestation to induce cleft palate. Before teratogen administration, the immune system of the female mice was stimulated by footpad injection with Freund's complete adjuvant (FCA) or by intraperitoneal injection with interferon-gamma (IFN-gamma). RESULTS Maternal immunostimulation with interferon-gamma (IFN-gamma) decreased severity of the cleft palate lesion caused by urethane, while FCA decreased both incidence and severity of cleft palate. Gestation day 14 fetuses from urethane-exposed mothers displayed decreased expression of cell cycle/apoptotic genes bcl2alpha, bcl2beta, pkCalpha, and p53 in fetal heads. Immune stimulation with IFN-gamma-normalized expression of bcl2alpha, bcl2beta, and pkCalpha to control levels. Urethane also decreased the ratio of expression of bclalpha/p53, bclbeta/p53, and pkCalpha/p53, while maternal injection with IFN-gamma restored these expression ratios to control levels. Maternal immunization with FCA also significantly increased bcl2alpha/p53, bcl2beta/p53, and pkCalpha/p53 gene expression ratios. CONCLUSIONS These results suggest that (1) the maternal immune system may possess heretofore unrecognized regulatory activity in fetal development, and (2) protection against urethane-induced cleft palate may be mediated through maternal immune regulation of fetal gene expression.
Collapse
MESH Headings
- Abnormalities, Drug-Induced/genetics
- Abnormalities, Drug-Induced/prevention & control
- Adjuvants, Immunologic/pharmacology
- Adjuvants, Immunologic/therapeutic use
- Animals
- Apoptosis/genetics
- Cell Cycle/genetics
- Cleft Palate/chemically induced
- Cleft Palate/embryology
- Cleft Palate/prevention & control
- Embryonic and Fetal Development/drug effects
- Embryonic and Fetal Development/genetics
- Female
- Fetal Proteins/genetics
- Foot
- Freund's Adjuvant/administration & dosage
- Freund's Adjuvant/pharmacology
- Freund's Adjuvant/therapeutic use
- Gene Expression Regulation, Developmental/drug effects
- Genes, bcl-2
- Genes, p53
- Injections
- Injections, Intraperitoneal
- Interferon-gamma/administration & dosage
- Interferon-gamma/pharmacology
- Interferon-gamma/therapeutic use
- Isoenzymes/genetics
- Male
- Mice
- Mice, Inbred ICR
- Pregnancy/immunology
- Protein Kinase C/genetics
- Protein Kinase C-alpha
- RNA, Messenger/analysis
- Receptors, Retinoic Acid/genetics
- Retinoid X Receptors
- Teratogens/toxicity
- Transcription Factors/genetics
- Urethane/toxicity
Collapse
|
69
|
Eisses KT. Concurrent teratogenic and mutagenic action of 2-methoxyethanol in Drosophila melanogaster larvae resulted in similar phenotypes: close resemblance to directed mutations. TERATOGENESIS, CARCINOGENESIS, AND MUTAGENESIS 2000; 19:183-204. [PMID: 10379843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Early third instar larvae of wild-type Drosophila melanogaster were transferred to medium supplemented with 2-methoxyethanol (2-ME) or ethylene glycol monomethyl ether. 2-ME produced terata in adult flies as wing notches and duplications of macrochaetae similar to feeding with methoxyacetic acid (MAA), the oxidation product of 2-ME. Larval feeding with 2-ME also affected the fertility of both females and males. 2-ME or more likely its intermediate oxidation product, methoxyacetaldehyde (MAALD), concurrently generated mutations in the premeiotic stages of the oocytes in the early third instar larvae. The mutagenicity of 2-ME has been confirmed in subsequent small scale experiments. The mutation frequency ranged from 4 x 10(-4) to 1 x 10(-2). Although terata were not supposed to be heritable, 1.1 to 8.7% of the affected females produced offspring with phenotypic similarity to the female parent. This phenomenon looked like a classical example of inheritance of an acquired character. The question is addressed why a Notch-like phenocopy, generated by larval 2-ME treatment, could bring forth Notch and rudimentary mutants in particular. Administration of 2-ME to larvae, containing the highly active alcohol dehydrogenase variant ADH-71k, exposed the mitotic germ cells and the mitotic somatic cells of the imaginal discs simultaneously to the mutagen MAALD and the teratogen MAA, respectively. The chances for specific gene mutations, though non-adaptive, were likely increased by a feedback mechanism: gene-products that were inhibited or disturbed by the teratogen demanded increased transcription of their encoding genes. Transcribed genes are more susceptible to mutagens.
Collapse
|
70
|
Munroe RJ, Bergstrom RA, Zheng QY, Libby B, Smith R, John SW, Schimenti KJ, Browning VL, Schimenti JC. Mouse mutants from chemically mutagenized embryonic stem cells. Nat Genet 2000; 24:318-21. [PMID: 10700192 PMCID: PMC2868360 DOI: 10.1038/73563] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The drive to characterize functions of human genes on a global scale has stimulated interest in large-scale generation of mouse mutants. Conventional germ-cell mutagenesis with N-ethyl-N-nitrosourea (ENU) is compromised by an inability to monitor mutation efficiency, strain and interlocus variation in mutation induction, and extensive husbandry requirements. To overcome these obstacles and develop new methods for generating mouse mutants, we devised protocols to generate germline chimaeric mice from embryonic stem (ES) cells heavily mutagenized with ethylmethanesulphonate (EMS). Germline chimaeras were derived from cultures that underwent a mutation rate of up to 1 in 1,200 at the Hprt locus (encoding hypoxanthine guanine phosphoribosyl transferase). The spectrum of mutations induced by EMS and the frameshift mutagen ICR191 was consistent with that observed in other mammalian cells. Chimaeras derived from ES cells treated with EMS transmitted mutations affecting several processes, including limb development, hair growth, hearing and gametogenesis. This technology affords several advantages over traditional mutagenesis, including the ability to conduct shortened breeding schemes and to screen for mutant phenotypes directly in ES cells or their differentiated derivatives.
Collapse
|
71
|
Abstract
We propose that thalidomide affects the following pathway during limb development: Growth factors (FGF-2 and IGF-I) attach to receptors on limb bud mesenchymal cells and initiate some second messenger system (perhaps SP-1), which activates alphav and beta3 integrin subunit genes. The resulting alphav beta3 integrin proteins stimulate angiogenesis in the developing limb bud. Several steps in this pathway depend on the activation of genes with primarily GC promoters (GGGCGG). Thalidomide, or a hydrolysis or metabolic breakdown product, specifically binds to GC promoter sites and inhibits the transcription of those genes. Inhibition of the genes interferes with normal angiogenesis, which results in truncation of the limb.
Collapse
|
72
|
Das P, Mohanty-Hejmadi P. Vitamin A mediated limb deformities in the common Indian toad, Bufo melanostictus (Schneider). INDIAN JOURNAL OF EXPERIMENTAL BIOLOGY 2000; 38:258-64. [PMID: 10927869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Several types of limb deformities were induced by vitamin A in B. melanostictus. These ranged from total suppression of all the limbs (ectromelia) to partial development of either the forelimb or the hindlimb or both (mesomelia) to reduction or absence of digits in either the forelimbs or hindlimbs or both and absence of long bones in either the forelimbs or hindlimbs or both (phocomelia) or duplication of the hindlimbs (polymelia). All the limb abnormalities were induced in the developing limbs of the tail amputated tadpoles of B. melanostictus following vitamin A treatment, which is all the more interesting. The results suggest that vitamin A induces the above mentioned abnormalities by either switching on or over-expressing or disrupting the limb-specific hox genes by yet unknown mechanisms.
Collapse
|
73
|
Faiella A, Wernig M, Consalez GG, Hostick U, Hofmann C, Hustert E, Boncinelli E, Balling R, Nadeau JH. A mouse model for valproate teratogenicity: parental effects, homeotic transformations, and altered HOX expression. Hum Mol Genet 2000; 9:227-36. [PMID: 10607833 DOI: 10.1093/hmg/9.2.227] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Valproate (VPA) is one of several effective anti-epileptic and mood-stabilizing drugs, many of which are also potent teratogens in humans and several other mammalian species. Variable teratogenicity among inbred strains of laboratory mice suggests that genetic factors influence susceptibility. While studying the genetic basis for VPA teratogenicity in mice, we discovered that parental factors influence fetal susceptibility to induced malformations. Detailed examination of these malformations revealed that many were homeotic transformations. To test whether VPA, like retinoic acid (RA), alters HOX expression, pluripotent human embryonal carcinoma cells were treated with VPA or RA and Hox expression assessed. Altered expression of specific Hox genes may thus account for the homeotic transformations and other malformations found in VPA-treated fetuses.
Collapse
MESH Headings
- Abnormalities, Drug-Induced/genetics
- Abnormalities, Multiple/chemically induced
- Abnormalities, Multiple/genetics
- Animals
- Anticonvulsants/toxicity
- Carcinoma, Embryonal/genetics
- Disease Models, Animal
- Female
- Fetal Weight/drug effects
- Fetus/abnormalities
- Fetus/drug effects
- Gene Expression Regulation, Developmental/drug effects
- Genes, Homeobox/drug effects
- Genes, Lethal
- Humans
- Maternal-Fetal Exchange/drug effects
- Maternal-Fetal Exchange/genetics
- Mice
- Mice, Inbred AKR
- Mice, Inbred BALB C
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Pregnancy
- Valproic Acid/toxicity
Collapse
|
74
|
Hovland DN, Cantor RM, Lee GS, Machado AF, Collins MD. Identification of a murine locus conveying susceptibility to cadmium-induced forelimb malformations. Genomics 2000; 63:193-201. [PMID: 10673332 DOI: 10.1006/geno.1999.6069] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The heavy metal cadmium (Cd), an environmentally ubiquitous contaminant, is a potent teratogen in mice. When administered parenterally, it induces an array of malformations that vary in scope and severity with the route, dose, time of administration, and the strain of the animal. When administered intraperitoneally on day 9.0 of gestation, 4 mg/kg cadmium chloride produces forelimb defects (predominantly ectrodactyly) in over 80% of fetuses of the C57BL/6 mouse strain, while no limb defects are observed in the identically treated SWV strain. Like other examples of strain-specific teratogenic activity, the underlying nature of the differential susceptibility remains unknown. The present study investigates the segregation of sensitivity to Cd-induced forelimb defects in crosses between C57BL/6 and SWV mice and provides evidence for the involvement of both maternal and fetal factors in the determination of defect expression. In addition, quantitative trait loci (QTL) analysis of the fetal genetic component was performed among 198 backcross progeny, utilizing a genomic linkage map of 149 informative microsatellite markers. One QTL demonstrating significant linkage to expression of the defect, designated Cadfar (cadmium-induced forelimb autopod reduction), was mapped to the distal end of chromosome 6 with a lod score of 3.1.
Collapse
|
75
|
Reardon W, Smith A, Honour JW, Hindmarsh P, Das D, Rumsby G, Nelson I, Malcolm S, Adès L, Sillence D, Kumar D, DeLozier-Blanchet C, McKee S, Kelly T, McKeehan WL, Baraitser M, Winter RM. Evidence for digenic inheritance in some cases of Antley-Bixler syndrome? J Med Genet 2000; 37:26-32. [PMID: 10633130 PMCID: PMC1734444 DOI: 10.1136/jmg.37.1.26] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The Antley-Bixler syndrome has been thought to be caused by an autosomal recessive gene. However, patients with this phenotype have been reported with a new dominant mutation at the FGFR2 locus as well as in the offspring of mothers taking the antifungal agent fluconazole during early pregnancy. In addition to the craniosynostosis and joint ankylosis which are the clinical hallmarks of the condition, many patients, especially females, have genital abnormalities. We now report abnormalities of steroid biogenesis in seven of 16 patients with an Antley-Bixler phenotype. Additionally, we identify FGFR2 mutations in seven of these 16 patients, including one patient with abnormal steroidogenesis. These findings, suggesting that some cases of Antley-Bixler syndrome are the outcome of two distinct genetic events, allow a hypothesis to be formulated under which we may explain all the differing and seemingly contradictory circumstances in which the Antley-Bixler phenotype has been recognised.
Collapse
|