tretinoin and Abnormalities--Multiple

Caudal regression syndrome (CRS) represents a spectrum of clinical phenotypes with varying degrees of malformation of the lower body with involvement of structures deriving from all 3 layers of the trilaminar embryo. We review areas of active investigation in the diagnosis, etiology, epidemiology, and treatment of the disease with a focus on underlying genetics. CRS pathobiology is complex and multifactorial with a significant contribution from environmental factors as evidenced in twin studies. Contemporary genomic and genetic investigations in both human primary tissue and murine in vitro and in vivo models implicate various genes associated with caudal differentiation and neural cell migration in embryogenesis. A large number of identified targets center around the metabolic regulation of retinoic acid and its derivatives. Dysregulation of retinoic acid homeostasis has been associated with abnormal embryonic cell migration, differentiation, and organogenesis with resulting malformations and agenesis in both a laboratory and a clinical setting. There appears to be a significant overlap in potential genetic targets with CRS and other developmental syndromes with similar presentations, such as VACTERL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities) association. CRS represents a spectrum of caudal developmental abnormalities with treatment options limited to mild and moderate expressions of disease. Continued research is necessary to further clarify mechanisms of disease pathobiology and complex polygenetic and environmental interaction. Despite this, progress has been made in identifying genetic targets and downstream effectors contributing to preclinical and clinical progression.

Topics: Abnormalities, Multiple; Animals; Genomics; Humans; Limb Deformities, Congenital; Nervous System Malformations; Tretinoin

Congenital diaphragmatic hernia (CDH) is a common cause of severe neonatal respiratory distress. Mortality and morbidity are determined by the amount of pulmonary hypoplasia (PH) that occurs and by the development of therapy-resistant pulmonary hypertension. The pathogenesis and aetiology of CDH and its associated anomalies are still largely unknown despite all research efforts. The pathogenesis of CDH is based on an assumption linking herniation of abdominal viscera into the thorax with compression of the developing lung. PH, however, can also result from reduced distension of the developing lung secondary to impaired fetal breathing movements. Our understanding of CDH has also been aided by basic research with the use of dietary, teratogen-induced, and knockout models of CDH. These studies indicate that lung hypoplasia may involve disturbances of mitogenic signalling pathways fundamental to embryonic lung development. Recent data reveal the role of disruption of a retinoid-signalling pathway in the pathogenesis of CDH. Although multifactorial inheritance may best explain most cases of CDH in humans, much has been learned about the genetic factors that play a role in the development of CDH by studies of patients with CDH caused by specific genetic syndromes and chromosome anomalies. More research is warranted to improve our understanding of normal and abnormal lung development in relation to CDH. Such investigations will help in the design of new treatment strategies to improve the natural course or even to prevent this anomaly.

Topics: Abnormalities, Multiple; Animals; Disease Models, Animal; Female; Genetic Association Studies; Gestational Age; Hernia, Diaphragmatic; Hernias, Diaphragmatic, Congenital; Humans; Infant, Newborn; Lung; Mice; Mice, Knockout; Persistent Fetal Circulation Syndrome; Pregnancy; Prenatal Exposure Delayed Effects; Respiratory Distress Syndrome, Newborn; Risk Factors; Tretinoin; Vitamin A

This review describes some of the properties of retinoic acid (RA) in its functions as a locally synthesized differentiation factor for the developing nervous system. The emphasis is on the characterization of the metabolic enzymes that synthesize and inactivate RA, and which determine local RA concentrations. These enzymes create regions of autocrine and paracrine RA signaling in the embryo. One mechanism by which RA can act as a differentiation agent is through the induction of growth factors and their receptors. Induction of growth factor receptors in neural progenitor cells can lead to growth factor dependency, and the consequent developmental fate of the cell will depend on the local availability of growth factors. Because RA activates the early events of cell differentiation, which then induce context-specific differentiation programs, RA may be called a master differentiation factor.

Topics: Abnormalities, Multiple; Animals; Cell Differentiation; Gene Expression Regulation, Developmental; Humans; Nervous System; Signal Transduction; Tretinoin; Vitamin A

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Female; Fetus; Humans; Infant, Newborn; Isotretinoin; Neural Crest; Pregnancy; Prenatal Exposure Delayed Effects; Tretinoin

DiGeorge syndrome (DGS) is a developmental defect which associates hypo- or aplasia of the thymus and parathyroids, facial dysmorphism and conotruncal cardiac malformations. The etiological factor in a great majority of DGS patients is monosomy for the 22q11.2 chromosomal region either through a large interstitial deletion of that region (inherited or de novo) or through an unbalanced translocation involving chromosome 22. In one instance, a balanced translocation of chromosome 22 was associated with a DGS phenotype. Extensive analyses of this region of chromosome 22 has led to the obtention of precise physical maps of the corresponding genomic region, to the cloning of the balanced translocation breakpoint and to the isolation of different genes from the minimal critical deleted region.

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Animals; Chromosome Aberrations; Chromosome Deletion; Chromosome Disorders; Chromosome Mapping; Chromosomes, Human, Pair 22; DiGeorge Syndrome; Female; Genes; Humans; Infant, Newborn; Male; Pregnancy; Pregnancy Complications; Rats; Syndrome; Translocation, Genetic; Tretinoin

Retinoic acid signaling plays a critical role during embryogenesis and requires tight regulation. Exposure to exogenous retinoic acid during fetal development is known to have teratogenic effects, producing a recognizable embryopathy.. We describe a case of retinoic acid embryopathy secondary to maternal isotretinoin use until the ninth week of gestation and expand the phenotype to include the rare features of parietal bone agenesis and athelia. Histology of the parietal region showed fibrous tissue with no intramembranous ossification. The fetus also had multiple craniofacial dysmorphisms, thymic agenesis, and transposition of the great arteries with double outlet right ventricle and subaortic perimembranous ventricular septal defect. Neuropathology revealed enlarged ventricles with agenesis of the cerebellar vermis, focal duplication of the central canal and scattered parenchymal ependymal rests, and possible cerebral heterotopias with associated abnormal neuronal lamination. A chromosomal microarray was normal.. Parietal bone agenesis and athelia are both rare congenital anomalies not previously reported in retinoic acid embryopathy. However, retinoic acid or its degrading enzyme has been demonstrated to exert effects in both of these developmental pathways, offering biological plausibility. We propose that this case may represent an expansion of the phenotype of retinoic embryopathy.

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Breast Diseases; Congenital Microtia; Female; Fetal Diseases; Humans; Parietal Bone; Phenotype; Tamoxifen; Transposition of Great Vessels; Tretinoin

This study shows a causal association between ALDH1A2 variants and a novel, severe multiple congenital anomaly syndrome in humans that is neonatally lethal due to associated pulmonary hypoplasia and respiratory failure. In two families, exome sequencing identified compound heterozygous missense variants in ALDH1A2. ALDH1A2 is involved in the conversion of retinol (vitamin A) into retinoic acid (RA), which is an essential regulator of diaphragm and cardiovascular formation during embryogenesis. Reduced RA causes cardiovascular, diaphragmatic, and associated pulmonary defects in several animal models, matching the phenotype observed in our patients. In silico protein modeling showed probable impairment of ALDH1A2 for three of the four substitutions. In vitro studies show a reduction of RA. Few pathogenic variants in genes encoding components of the retinoic signaling pathway have been described to date, likely due to embryonic lethality. Thus, this study contributes significantly to knowledge of the role of this pathway in human diaphragm and cardiovascular development and disease. Some clinical features in our patients are also observed in Fryns syndrome (MIM# 229850), syndromic microphthalmia 9 (MIM# 601186), and DiGeorge syndrome (MIM# 188400). Patients with similar clinical features who are genetically undiagnosed should be tested for recessive ALDH1A2-deficient malformation syndrome.

Topics: Abnormalities, Multiple; Aldehyde Dehydrogenase 1 Family; Animals; Cardiovascular Diseases; Diaphragm; Humans; Lung Diseases; Retinal Dehydrogenase; Syndrome; Tretinoin

The arterial and venous poles of the mammalian heart are hotspots of congenital heart defects (CHD) such as those observed in 22q11.2 deletion (or DiGeorge) and Holt-Oram syndromes. These regions of the heart are derived from late differentiating cardiac progenitor cells of the Second Heart Field (SHF) located in pharyngeal mesoderm contiguous with the elongating heart tube. The T-box transcription factor Tbx1, encoded by the major 22q11.2 deletion syndrome gene, regulates SHF addition to both cardiac poles from a common progenitor population. Despite the significance of this cellular addition the mechanisms regulating the deployment of common progenitor cells to alternate cardiac poles remain poorly understood. Here we demonstrate that Tbx5, mutated in Holt-Oram syndrome and essential for venous pole development, is activated in Tbx1 expressing cells in the posterior region of the SHF at early stages of heart tube elongation. A subset of the SHF transcriptional program, including Tbx1 expression, is subsequently downregulated in Tbx5 expressing cells, generating a transcriptional boundary between Tbx1-positive arterial pole and Tbx5-positive venous pole progenitor cell populations. We show that normal downregulation of the definitive arterial pole progenitor cell program in the posterior SHF is dependent on both Tbx1 and Tbx5. Furthermore, retinoic acid (RA) signaling is required for Tbx5 activation in Tbx1-positive cells and blocking RA signaling at the time of Tbx5 activation results in atrioventricular septal defects at fetal stages. Our results reveal sequential steps of cardiac progenitor cell patterning and provide mechanistic insights into the origin of common forms of CHD.

Topics: Abnormalities, Multiple; Animals; Coronary Vessels; DiGeorge Syndrome; Gene Expression Regulation, Developmental; Heart Defects, Congenital; Heart Septal Defects; Heart Septal Defects, Atrial; Lower Extremity Deformities, Congenital; Mice; Mice, Transgenic; Signal Transduction; Stem Cells; T-Box Domain Proteins; Tretinoin; Upper Extremity Deformities, Congenital

Vertebrate body axis extension occurs in a head-to-tail direction from a caudal progenitor zone that responds to interacting signals. Wnt/β-catenin signaling is critical for generation of paraxial mesoderm, somite formation, and maintenance of the axial stem cell pool. Body axis extension requires Wnt8a in lower vertebrates, but in mammals Wnt3a is required, although the anterior trunk develops in the absence of Wnt3a.. We examined mouse Wnt8a(-/-) and Wnt3a(-/-) single and double mutants to explore whether mammalian Wnt8a contributes to body axis extension and to determine whether a posterior growth function for Wnt8a is conserved throughout the vertebrate lineage. We find that caudal Wnt8a is expressed only during early somite stages and is required for normal development of the anterior trunk in the absence of Wnt3a. During this time, we show that Wnt8a and Wnt3a cooperate to maintain Fgf8 expression and prevent premature Sox2 up-regulation in the axial stem cell niche, critical for posterior growth. Similar to Fgf8, Wnt8a requires retinoic acid (RA) signaling to restrict its caudal expression boundary and possesses an upstream RA response element that binds RA receptors.. These findings provide new insight into interaction of caudal Wnt-FGF-RA signals required for body axis extension.

Topics: Abnormalities, Multiple; Alcohol Oxidoreductases; Animals; Body Patterning; Conserved Sequence; Fibroblast Growth Factor 8; Gastrulation; Gene Expression Regulation, Developmental; Homeodomain Proteins; Intercellular Signaling Peptides and Proteins; Mice; Mice, Knockout; Phenotype; Receptors, Retinoic Acid; Response Elements; Signal Transduction; Somites; SOXB1 Transcription Factors; Stem Cell Niche; Tretinoin; Vertebrates; Wnt Proteins; Wnt3A Protein

Despite technical advances in the surgical/medical care of anorectal malformation (ARM), persistent unsatisfactory postoperative bowel habit has been attributed to histopathologic abnormalities of the distal rectum/pouch (DRP) and hypoplasia of anal sphincter muscles (ASM). We used Sox10-Venus mice with ARM induced by all-trans retinoic acid (ATRA) to investigate neural crest cell (NCC) innervation in the DRP and ASM.. Pregnant Sox10-Venus mice were administered single doses of 50, 70, or 100 mg/kg of ATRA on embryonic day 8.5 (E8.5) then sacrificed on either E16.5 or E19.5. Bowel specimens comprising the anorectum were examined using fluorescence microscopy without immunohistochemical staining (FMIS). Anti-PGP9.5 was used to delineate ganglion cells and anti-SMA for smooth muscles.. The appropriate dose of ATRA for inducing ARM was 50 mg/kg. Under FMIS, all ARM embryos (n = 5; all high type; 3 male:2 female) had less NCC innervation with thick Venus-positive nerve fibers in the DRP compared with normal embryos (n = 8); there was abnormal NCC innervation in the DRP and absent ASM in ARM mice.. We are the first to delineate abnormal enteric nervous system innervation in the DRP of ARM mice without using immunohistochemical staining techniques thus allowing specimens to be examined without any distortion.

Topics: Abnormalities, Multiple; Anal Canal; Animals; Anorectal Malformations; Anus, Imperforate; Disease Models, Animal; Female; Intestines; Male; Mice; Microscopy, Fluorescence; Neural Crest; Rectum; Tretinoin

Rare, recurrent genomic imbalances facilitate the association of genotype with abnormalities at the "whole body" level. However, at the cellular level, the functional consequences of recurrent genomic abnormalities and how they can be linked to the phenotype are much less investigated.. We report an example of a functional analysis of two genes from a new, overlapping microdeletion of 2p13.2 region (from 72,140,702-72,924,626). The subjects shared intellectual disability (ID), language delay, hyperactivity, facial asymmetry, ear malformations, and vertebral and/or craniofacial abnormalities. The overlapping region included two genes, EXOC6B and CYP26B1, which are involved in exocytosis/Notch signaling and retinoic acid (RA) metabolism, respectively, and are of critical importance for early morphogenesis, symmetry as well as craniofacial, skeleton and brain development. The abnormal function of EXOC6B was documented in patient lymphoblasts by its reduced expression and with perturbed expression of Notch signaling pathway genes HES1 and RBPJ, previously noted to be the consequence of EXOC6B dysfunction in animal and cell line models. Similarly, the function of CYP26B1 was affected by the deletion since the retinoic acid induced expression of this gene in patient lymphoblasts was significantly lower compared to controls (8% of controls).. Haploinsufficiency of CYP26B1 and EXOC6B genes involved in retinoic acid and exocyst/Notch signaling pathways, respectively, has not been reported previously in humans. The developmental anomalies and phenotypic features of our subjects are in keeping with the dysfunction of these genes, considering their known role. Documenting their dysfunction at the cellular level in patient cells enhanced our understanding of biological processes which contribute to the clinical phenotype.

Topics: Abnormalities, Multiple; Adolescent; Bone Diseases, Developmental; Cell Line; Child; Chromosome Deletion; Chromosomes, Human, Pair 2; Craniofacial Abnormalities; Cytochrome P-450 Enzyme System; Developmental Disabilities; Exocytosis; Genotype; GTP-Binding Proteins; Haploinsufficiency; Humans; Male; Oligonucleotide Array Sequence Analysis; Phenotype; Retinoic Acid 4-Hydroxylase; Tretinoin

TBX3, a member of the T-box transcription factor gene family, is a transcriptional repressor that is required for the development of the heart, limbs, and mammary glands. Mutations in TBX3 that result in reduced functional protein lead to ulnar-mammary syndrome, a developmental disorder characterized by limb, mammary gland, tooth, and genital abnormalities. Increased levels of TBX3 have been shown to contribute to the oncogenic process, and TBX3 is overexpressed in several cancers, including breast cancer, liver cancer, and melanoma. Despite its important role in development and postnatal life, little is known about the signaling pathways that modulate TBX3 expression. Here we show, using in vitro and in vivo assays, that retinoic acid (RA) activates endogenous TBX3 expression, which is mediated by an RA-receptor complex directly binding and activating the TBX3 promoter, and we provide evidence that this regulation may be functionally relevant in mouse embryonic limb development. Our data identify TBX3 as a direct target of the RA signaling pathway and extend our understanding of the role and regulation of TBX3 in limb development.

Topics: Abnormalities, Multiple; Animals; Blotting, Western; Breast Diseases; Cell Line, Tumor; Embryo, Mammalian; Extremities; Female; Gene Expression Regulation, Developmental; HEK293 Cells; Humans; In Situ Hybridization; Luciferases; Male; Mice; Mice, Inbred ICR; Mutation; Promoter Regions, Genetic; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; Signal Transduction; T-Box Domain Proteins; Tretinoin; Ulna

Topics: Abnormalities, Multiple; Adult; Arthrogryposis; Facial Asymmetry; Female; Humans; Keratoderma, Palmoplantar; Neck; Scoliosis; Syndrome; Tretinoin

Retinoid-mediated signal transduction plays a crucial role in the embryonic development of various organs. We previously reported that retinoic acid induced anorectal malformations (ARM) in mice. GDF11 is a TGFβ superfamily molecule and is cleaved and activated by proprotein convertase subtilisin/kexin 5 (PCSK5). PCSK5 (PC5/6) mutations result in an abnormal expression of Hlxb9 and Hox genes, which include known GDF11 targets that are necessary for caudal development in vertebrate embryos. To determine a possible role of the retinoid-mediated signaling pathway in the pathogenesis of ARM, we investigated whether all-trans retinoic acid (ATRA) affected the expression patterns of PCSK5 and GDF11 in ARM-treated mouse embryos.. Pregnant ICR-Slc mice were administered 100 mg/kg ATRA by gavage on embryonic day (E) 9.0. Embryos were harvested between days E12 and E18, and mid-sagittal sections of the hindgut region were prepared for immunohistochemistry using antibodies against PCSK5 (PC5/6) and GDF11 (GDF8/11).. Over 95% of the embryos treated with ATRA showed ARM, with rectourethral fistula or rectocloacal fistula, and a short tail. Furthermore, most of these embryos exhibited sacral malformations, tethered spinal cords, and presacral masses resembling those malformations found in caudal regression syndrome. By E14, normal mouse embryos formed a rectum and anus, and the somites behind the hindgut were positive for PC5/6 and GDF8/11. In contrast, in ARM embryos, the somites behind the hindgut were negative for PC5/6 and GDF8/11.. ATRA treatment affected the caudal development in mouse embryos, resulting in anorectal, sacral, and spinal malformations, and inhibited PCSK5 and GDF11 expression in the hindgut region. These findings indicate that the expression of PCSK5 and GDF11, which plays a crucial role in the organogenesis of the hindgut, was disturbed in the hindgut region when retinoid-mediated signaling was disrupted. This study offers a new insight into the pathogenesis of ARM in mice as affected by the interaction between ATRA and PCSK5/GDF11.

Topics: Abnormalities, Multiple; Animals; Anorectal Malformations; Anus, Imperforate; Bone Morphogenetic Proteins; Colon; Female; Growth Differentiation Factors; Immunohistochemistry; Mice; Mice, Inbred ICR; Pregnancy; Proprotein Convertase 5; Rectal Fistula; Signal Transduction; Tail; Tretinoin

Retinoid-mediated signal transduction plays a crucial role in the embryogenesis of various organs. We previously reported the successful induction of anorectal malformations in mice using retinoic acid (RA). Retinoic acid controls the expression of essential target genes for cell differentiation, morphogenesis, and apoptosis through a complicated interaction in which RA receptors form heterodimers with retinoid X receptors. In the present study, we investigated whether the retinoid antagonist, LE135, could prevent the induction of anorectal malformations (ARMs) in mice.. Retinoic acid was intraperitoneally administered as 100 mg/kg of all-trans RA on E9; and then the retinoid antagonist, LE135, was intraperitoneally administered to pregnant ICR strain mice on the eighth gestational day (E8), 1 day before administration of RA (group B) or on E9, simultaneously (group C) with RA administration. All of the embryos were obtained from the uteri on E18. Frozen sections were evaluated for concentric layers around the endodermal epithelium by hematoxylin and eosin staining.. In group A, all of the embryos demonstrated ARM with rectoprostatic urethral fistula, or rectocloacal fistula, and all of the embryos showed the absence of a tail. In group B, 36% of the embryos could be rescued from ARM. However, all of the rescued embryos had a short tail that was shorter than their hind limb. The ARM rescue rates in group B were significantly improved compared to those in group A (P < .01). In group C, 45% of the embryos were rescued from ARM, but all of the rescued embryos had short tail. The ARM rescue rate in group C was significantly improved compared to that in group A (P < .01). However, there was no significant difference in the ARM rescue rate between group B and Group C.. The present study provides evidence that in the hindgut region, RAR selective retinoid antagonist, LE135, could rescue embryos from ARM. However, the disturbance of all-trans RA acid was limited to the caudal region. Further study to establish an appropriate rescue program for ARM in a mouse model might suggest a step toward protection against human ARM in the future.

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Anal Canal; Animals; Cloaca; Dibenzazepines; Drug Administration Schedule; Drug Evaluation, Preclinical; Female; Fistula; Gene Expression Regulation, Developmental; Humans; Injections, Intraperitoneal; Male; Mice; Mice, Inbred ICR; Models, Animal; Pregnancy; Prostatic Diseases; Random Allocation; Receptors, Retinoic Acid; Rectal Fistula; Rectum; Species Specificity; Tail; Tretinoin

Retinoic acid is a widely used drug in the treatment of cystic acne. It has teratogenic effects that depend on the gestational period in which it is used. We report a seven months old female whose mother was exposed to retinoic acid in both pre-gestational and gestational periods. She had a retardation of psychomotor development and a brain MRI showed frontal atrophy and a malformation of the posterior fossa. We discuss the mechanisms of the teratogenic effects of retinoic acid.

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Acne Vulgaris; Atrophy; Cranial Fossa, Posterior; Craniofacial Abnormalities; Female; Frontal Lobe; Humans; Infant; Isotretinoin; Keratolytic Agents; Maternal Exposure; Pregnancy; Prenatal Exposure Delayed Effects; Psychomotor Disorders; Teratogens; Tretinoin

The cellular uptake of vitamin A from its RBP4-bound circulating form (holo-RBP4) is a homeostatic process that evidently depends on the multidomain membrane protein STRA6. In humans, mutations in STRA6 are associated with Matthew-Wood syndrome, manifested by multisystem developmental malformations. Here we addressed the metabolic basis of this inherited disease. STRA6-dependent transfer of retinol from RBP4 into cultured NIH 3T3 fibroblasts was enhanced by lecithin:retinol acyltransferase (LRAT). The retinol transfer was bidirectional, strongly suggesting that STRA6 acts as a retinol channel/transporter. Loss-of-function analysis in zebrafish embryos revealed that Stra6 deficiency caused vitamin A deprivation of the developing eyes. We provide evidence that, in the absence of Stra6, holo-Rbp4 provokes nonspecific vitamin A excess in several embryonic tissues, impairing retinoic acid receptor signaling and gene regulation. These fatal consequences of Stra6 deficiency, including craniofacial and cardiac defects and microphthalmia, were largely alleviated by reducing embryonic Rbp4 levels by morpholino oligonucleotide or pharmacological treatments.

Topics: Abnormalities, Multiple; Acyltransferases; Animals; Cardiovascular Abnormalities; Craniofacial Abnormalities; Disease Models, Animal; Eye; Gene Deletion; Gene Expression Regulation, Developmental; Homeostasis; Humans; Membrane Proteins; Membrane Transport Proteins; Mice; Morpholines; NIH 3T3 Cells; Oligonucleotides, Antisense; Retinol-Binding Proteins, Plasma; Syndrome; Time Factors; Transduction, Genetic; Tretinoin; Vitamin A; Zebrafish; Zebrafish Proteins

Regulation of patterning and morphogenesis during embryonic development depends on tissue-specific signaling by retinoic acid (RA), the active form of Vitamin A (retinol). The first enzymatic step in RA synthesis, the oxidation of retinol to retinal, is thought to be carried out by the ubiquitous or overlapping activities of redundant alcohol dehydrogenases. The second oxidation step, the conversion of retinal to RA, is performed by retinaldehyde dehydrogenases. Thus, the specific spatiotemporal distribution of retinoid synthesis is believed to be controlled exclusively at the level of the second oxidation reaction. In an N-ethyl-N-nitrosourea (ENU)-induced forward genetic screen we discovered a new midgestation lethal mouse mutant, called trex, which displays craniofacial, limb, and organ abnormalities. The trex phenotype is caused by a mutation in the short-chain dehydrogenase/reductase, RDH10. Using protein modeling, enzymatic assays, and mutant embryos, we determined that RDH10(trex) mutant protein lacks the ability to oxidize retinol to retinal, resulting in insufficient RA signaling. Thus, we show that the first oxidative step of Vitamin A metabolism, which is catalyzed in large part by the retinol dehydrogenase RDH10, is critical for the spatiotemporal synthesis of RA. Furthermore, these results identify a new nodal point in RA metabolism during embryogenesis.

Topics: Abnormalities, Multiple; Alcohol Oxidoreductases; Animals; Body Patterning; Embryonic Development; Extremities; Facial Bones; Female; Genes, Lethal; Male; Maternal Nutritional Physiological Phenomena; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Models, Molecular; Mutation; Phenotype; Pregnancy; Signal Transduction; Skull; Tretinoin

This review highlights the relevance of the neural crest (NC) as a developmental control mechanism involved in several pediatric surgical conditions and the investigative interest of following some of its known signaling pathways.. The participation of the NC in facial clefts, ear defects, branchial fistulae and cysts, heart outflow tract and aortic arch anomalies, pigmentary disorders, abnormal enteric innervation, neural tumors, hemangiomas, and vascular anomalies is briefly reviewed. Then, the literature on clinical and experimental esophageal atresia-tracheoesophageal fistula (EA-TEF) and congenital diaphragmatic hernia (CDH) is reviewed for the presence of associated NC defects. Finally, some of the molecular signaling pathways involved in both conditions (sonic hedgehog, Hox genes, and retinoids) are summarized.. The association of facial, cardiovascular, thymic, parathyroid, and C-cell defects together with anomalies of extrinsic and intrinsic esophageal innervation in babies and/or animals with both EA-TEF and CDH strongly supports the hypothesis that NC is involved in the pathogenesis of these malformative clusters. On the other hand, both EA-TEF and CDH are observed in mice mutant for genes involved in the previously mentioned signaling pathways.. The investigation of NC-related molecular pathogenic pathways involved in malformative associations like EA-TEF and CDH that are induced by chromosomal anomalies, chemical teratogens, and engineered mutations is a promising way of clarifying why and how some pediatric surgical conditions occur. Pediatric surgeons should be actively involved in these investigations.

Topics: Abnormalities, Multiple; Blood Vessels; Branchial Region; Cardiovascular Abnormalities; Cell Lineage; Cell Movement; Child; Child, Preschool; Enteric Nervous System; Esophageal Atresia; Face; Genes, Homeobox; Hedgehog Proteins; Hernia, Diaphragmatic; Hernias, Diaphragmatic, Congenital; Homeodomain Proteins; Humans; Infant; Infant, Newborn; Neoplasms; Neural Crest; Patched Receptors; Pigmentation Disorders; Receptors, Cell Surface; Receptors, G-Protein-Coupled; Receptors, Retinoic Acid; Signal Transduction; Smoothened Receptor; Syndrome; Transcription Factors; Tretinoin; Zinc Finger Protein GLI1

Cyp26a1, a gene required for retinoic acid (RA) inactivation during embryogenesis, was previously identified as a potential Tbx1 target from a microarray screen comparing wild-type and null Tbx1 mouse embryo pharyngeal arches (pa) at E9.5. Using real-time PCR and in situ hybridization analysis of Cyp26a1 and its two functionally related family members Cyp26b1 and c1, we demonstrate reduced and/or altered expression for all three genes in pharyngeal tissues of Tbx1 null embryos. Blockade of Cyp26 function in the chick embryo using R115866, a specific inhibitor of Cyp26 enzyme function, resulted in a dose-dependent phenocopy of the Tbx1 null mouse including loss of caudal pa and pharyngeal arch arteries (paa), small otic vesicles, loss of head mesenchyme and, at later stages, DiGeorge Syndrome-like heart defects, including common arterial trunk and perimembranous ventricular septal defects. Molecular markers revealed a serious disruption of pharyngeal pouch endoderm (ppe) morphogenesis and reduced staining for smooth muscle cells in paa. Expression of the RA synthesizing enzyme Raldh2 was also up-regulated and altered Hoxb1 expression indicated that RA levels are raised in R115866-treated embryos as reported for Tbx1 null mice. Down-regulation of Tbx1 itself was observed, in accordance with previous observations that RA represses Tbx1 expression. Thus, by specifically blocking the action of the Cyp26 enzymes we can recapitulate many elements of the Tbx1 mutant mouse, supporting the hypothesis that the dysregulation of RA-controlled morphogenesis contributes to the Tbx1 loss of function phenotype.

Topics: Abnormalities, Multiple; Animals; Benzothiazoles; Chick Embryo; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; DiGeorge Syndrome; Down-Regulation; Male; Mice; Mice, Knockout; Retinoic Acid 4-Hydroxylase; T-Box Domain Proteins; Tretinoin; Triazoles

Retinoic acid (RA), the active vitamin A derivative, is an important developmental signaling molecule in vertebrates. In this study, we have assessed whether minimal numbers and/or specific distributions of RA-producing cells can support normal mouse embryonic development. Retinaldehyde dehydrogenase 2 (RALDH2) is the main RA-synthesizing enzyme acting during development. We have generated an embryonic stem (ES) cell line homozygous for an Raldh2 gene disruption, and have analyzed chimeric embryos with various contributions of wild-type cells. Whereas embryos almost completely derived from Raldh2(-/-) cells phenocopy the corresponding germline null mutants, the presence of even small numbers (<10%) of wild-type cells can rescue most of the morphogenetic defects, including embryonic turning and axial elongation, and left-right looping of the heart tube. No consistent bias in the distribution of wild-type cells was observed in the phenotypically rescued Raldh2(-/-) chimeras. Analysis of an RA-sensitive transgene indicates that RA can diffuse from wild-type cells and elicit a widespread transcriptional response in Raldh2-deficient cells. Our results show that few wild-type RA-producing cells, even when present in apparent random distributions, can support early morphogenesis of the mouse embryo. However, the Raldh2(-/-) chimeric fetuses display lung abnormalities, persistent truncus arteriosus, and abnormal myocardial differentiation, showing that subsequent RA-dependent events cannot be fully rescued by the mosaic presence of wild-type cells.

Topics: Abnormalities, Multiple; Aldehyde Oxidoreductases; Animals; Blastocyst; Cell Differentiation; Chimera; Chimerism; Embryonic Development; Embryonic Stem Cells; Mice; Mice, Transgenic; Mutation; Myocytes, Cardiac; Signal Transduction; Transgenes; Tretinoin

Renal malformations are common human birth defects that sometimes occur in the context of the caudal regression syndrome. Here, we found that exposure of pregnant mice to all-trans retinoic acid, at a time when the metanephros has yet to form, causes a failure of kidney development along with caudal regression. Maternal treatment with Am580 (retinoic acid receptor alpha agonist) also induced similar patterns of kidney maldevelopment in the fetus. In metanephroi from retinoic acid-treated pregnancies, renal mesenchyme condensed around the ureteric bud but then failed to differentiate into nephrons, instead undergoing involution by fulminant apoptosis to produce a renal agenesis phenotype. Results of whole organ cultures in serum-free medium, and also tissue recombination experiments, showed that the nephrogenic defect was intrinsic to the kidney and that it resided in the metanephric mesenchyme and not the ureteric bud. Renal mesenchyme from control embryos expressed Wilms' tumor 1 (Wt1), but this transcription factor, which is indispensable for kidney development, failed to express in metanephroi of retinoic acid-exposed embryos. Wt1 expression and organogenesis were both restored, however, when metanephroi from retinoic acid-treated pregnancies were grown in serum-containing media. Our data illuminate the pathobiology of a severe, teratogen-induced kidney malformation.

Topics: Abnormalities, Multiple; Anal Canal; Animals; Coculture Techniques; Congenital Abnormalities; Embryonic Development; Female; Gene Expression; Genes, Wilms Tumor; Kidney; Lumbar Vertebrae; Mesoderm; Mice; Mice, Inbred ICR; Spinal Cord; Syndrome; Tissue Culture Techniques; Tretinoin

Tethered spinal cord is frequently associated with anorectal malformations (ARMs). However, it remains unknown how the tethered spinal cord develops and relates to the severity of ARM. We studied the development of the spinal cord in ARM mouse embryos induced by all-trans retinoic acid (ATRA).. Pregnant ICR-Slc mice were administered 100 mg/kg of ATRA on the ninth embryonic day (E9.0). Embryonic specimens were obtained from the uteri between E11.0 and E18.5. Midsagittal histologic sections focusing on the spinal cord and pelvis were prepared for immuonhistochemistry specific for neurofilament and Protein Gene Product 9.5 molecules.. More than 98% of ATRA-treated embryos demonstrated ARM with rectourethral or rectocloacal fistula. Normal embryos exhibited progressive ascent of the spinal cord from E14.5. However, in ARM embryos, the distal spinal cord ended with meningomyelocelelike or atypical hamartomatous lesions at E11.5 to E13.5, which later caused stretch force that damaged the spinal cord, resulting in tethered cord between E16.0 and E16.5.. In ATRA-induced ARM mouse embryos, tethered spinal cord was mostly established, accompanied by caudal neural maldevelopment, during early fetal development. This experimental model may be useful for researching detailed neuropathologic conditions in ARM children accompanied with tethered spinal cord.

Topics: Abnormalities, Multiple; Anal Canal; Animals; Disease Models, Animal; Embryonic Development; Female; Humans; Immunohistochemistry; Mice; Mice, Inbred ICR; Mutagens; Neural Tube Defects; Pregnancy; Rectum; Tretinoin

The aim of this study was to determine the possible role of the retinoid-mediated signaling pathway in the pathogenesis of anorectal malformations (ARM). The authors investigated whether all-trans retinoic acid (ATRA) affects the expression pattern of Sonic hedgehog (Shh) and Bone morphogenetic protein 4 (BMP4), which play important roles in anorectal morphogenesis in vertebrates.. Pregnant ICR strain mice were fed 100 mg/kg of ATRA on the ninth gestational day (E9). Embryos with or without administration of ATRA were obtained from the uteri between E12 and E16 and were fixed immediately in a 4% paraformaldehyde solution. Frozen sections were evaluated for concentric layers around the endodermal epithelium by H&E and immunohistochemistry using antibodies created specifically to act against Shh and BMP4.. More than 95% of the embryos administered ATRA had ARM; rectoprostatic urethral fistula, rectocloacal fistula, and short tail were the most frequent anomalies in the mouse embryos. On E14, normal mouse embryos had normal rectum and anus in which the epithelium of the anorectum was positive for Shh, and the mesenchyme was positive for BMP4. In the ARM embryos, however, the epithelium of the anorectum was negative for Shh, and the mesenchyme was also negative for BMP4.. In normal hindgut development, Shh from the epithelium induces BMP4 expression in the mesenchyme, which differentiates into the lamina propria and the submucosa. In ARM embryos, expressions of Shh and BMP4 could not be found in those regions of the hindgut. Therefore, these findings indicate that Shh and BMP4, which appear to play a crucial role in organogenesis of the hindgut, were disturbed in the cell signaling pathway between the epithelium and the mesenchyme layers.

Topics: Abnormalities, Multiple; Anal Canal; Animals; Bone Morphogenetic Protein 4; Bone Morphogenetic Proteins; Cell Differentiation; Cloaca; Epithelium; Female; Fetal Death; Gene Expression Regulation, Developmental; Gestational Age; Hedgehog Proteins; Mesoderm; Mice; Mice, Inbred ICR; Morphogenesis; Organ Specificity; Pregnancy; Rectum; Signal Transduction; Tail; Trans-Activators; Tretinoin; Urethra; Urinary Bladder

Prenatal exposure of rat embryos to retinoic acid induces severe malformations involving various organs. The mechanisms of this embryopathy are known only in part. This study describes the malformations of the neural crest-derived organs in this model and shows that many of them fit into the pattern of disturbed neural crest organogenic control. Pregnant rats were exposed to either all-trans retinoic acid (125 mg/kg; n=17) or vehicle ( n=10) on E10. Fetuses were recovered on E21 and external and internal malformations were sought. The craniofacial area, the trachea, parathyroids, thymus, thyroid, heart, great vessels, and adrenals were examined. In contrast with normal controls, 100% of retinoic acid animals had craniofacial, 94% anorectal, 90% limb, and 55% neural tube defects. The thymus was absent or ectopic in 76%, the parathyroids were absent or single in 88%, and the thyroid was abnormal in 41%. There were neural crest-type (outflow tract and/or pharyngeal aortic arch defects) cardiovascular malformations in 90% and the adrenals were absent in 52%. Interestingly, 9 of 11 (88%) animals with neural tube defects had absent adrenal glands. This association was significant ( p<0.01) by Fisher exact test. Among the complex mechanisms of retinoic acid teratogenesis, severe disturbances of the neural crest pathway play a leading role. The simultaneous development of neural tube defects and adrenal agenesis suggests common pathogenic pathways.

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Animals; Drug Evaluation, Preclinical; Female; Fetus; Models, Animal; Neural Crest; Pregnancy; Prenatal Exposure Delayed Effects; Rats; Rats, Sprague-Dawley; Tretinoin; Vitamin A

Maternal diabetes increases the risk of congenital malformations in the offspring of affected pregnancies. This increase arises from the teratogenic effect of the maternal diabetic milieu on the developing embryo, although the mechanism of this action is poorly understood. In the present study, we examined whether the vitamin A metabolite retinoic acid (RA), a common drug with well-known teratogenic properties, may interact with maternal diabetes to alter the incidence of congenital malformations in mice. Our results show that when treated with RA, embryos of diabetic mice are significantly more prone than embryos of nondiabetic mice to develop caudal regression, a defect that is highly associated with diabetic pregnancy in humans. By studying the vestigial tail (Wnt-3a(vt)) mutant, we provide evidence that Wnt-3a, a gene that controls the development of the caudal region, is directly involved in the pathogenic pathway of RA-induced caudal regression. We further show that the molecular basis of the increased susceptibility of embryos of diabetic mice to RA involves enhanced downregulation of Wnt-3a expression. This positive interaction between RA and maternal diabetes may have implications for humans in suggesting increased susceptibility to environmental teratogens during diabetic pregnancy.

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Animals; Diabetes Mellitus, Experimental; Down-Regulation; Female; Genetic Predisposition to Disease; Mice; Mice, Inbred ICR; Mutation; Pregnancy; Pregnancy in Diabetics; Proteins; Teratogens; Tretinoin; Wnt Proteins; Wnt3 Protein; Wnt3A Protein

The active derivative of vitamin A, retinoic acid (RA), is essential for normal embryonic development. The spatio-temporal distribution of embryonic RA results from regulated expression of RA-synthesizing retinaldehyde dehydrogenases and RA-metabolizing cytochrome P450s (CYP26). Excess RA administration or RA deficiency results in a complex spectrum of embryonic abnormalities. As a first step in understanding the developmental function of RA-metabolizing enzymes, we have disrupted the murine Cyp26A1 gene. We report that Cyp26A1-null mutants die during mid-late gestation and show a number of major morphogenetic defects. Spina bifida and truncation of the tail and lumbosacral region (including abnormalities of the kidneys, urogenital tract, and hindgut) are the most conspicuous defects, leading in extreme cases to a sirenomelia ("mermaid tail") phenotype. Cyp26A1 mutants also show posterior transformations of cervical vertebrae and abnormal patterning of the rostral hindbrain, which appears to be partially posteriorly transformed. These defects correlate with two major sites of Cyp26A1 expression in the rostral neural plate and embryonic tail bud. Because all of the Cyp26A1(-/-) abnormalities closely resemble RA teratogenic effects, we postulate that the key function of CYP26A1 is to maintain specific embryonic areas in a RA-depleted state, to protect them against the deleterious effect of ectopic RA signaling.

Topics: Abnormalities, Multiple; Animals; Base Sequence; Body Patterning; Cytochrome P-450 Enzyme System; DNA Primers; Extremities; Gene Targeting; Mice; Mice, Knockout; Mixed Function Oxygenases; Phenotype; Retinoic Acid 4-Hydroxylase; Rhombencephalon; Signal Transduction; Spine; Tretinoin

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Animals; Embryo, Mammalian; Female; Humans; Mice; Pregnancy; Tretinoin

Normal embryonic development and survival in utero is dependent on an adequate supply of vitamin A. Embryos from vitamin A-deficient (VAD) pregnant rats fed an inadequate amount of all-trans retinoic acid (atRA; 12 microg per g of diet or approximately 230 microg per rat per day) exhibit severe developmental abnormalities of the anterior cardinal vein and hindbrain by embryonic day (E) 12.5 and die shortly thereafter.. In the present study, we sought to determine whether supplementation of VAD-RA supported (12 microg per g of diet) pregnant rats with retinol (ROL) at the late-gastrula (presomite or rat E9.5) or early somite stages (E10.5), or provision of higher levels of atRA throughout this period could prevent abnormalities in the developing cardiovascular and nervous systems.. A newly described defect in the sinuatrial venus valve along with enlarged anterior cardinal veins and nervous system abnormalities and the later death of embryos are prevented by supplementing pregnant animals with ROL on the morning of E9.5. If ROL supplementation is delayed by 1 day (E10.5), most embryos are abnormal and die by E18.5. Supplementation of VAD rats with atRA (250 microg per g of diet) between E8.5 and E10.5 also prevents the cardiovascular and nervous system abnormalities and a significant number of these embryos survive to parturition. Thus, high levels of atRA can obviate the need for ROL between E9.5 and E10.5.. These results support an essential role for retinoid signaling between the late gastrula and early somite stages in the rat embryo for normal morphogenesis of the primitive heart tube and the posterior hindbrain. Further, these results suggest that embryonic death occurring at midgestation in the VAD rat may be linked to the abnormal development of one or both of these embryonic structures.

Topics: Abnormalities, Multiple; Animal Feed; Animals; Cranial Nerves; Diterpenes; Dose-Response Relationship, Drug; Embryonic and Fetal Development; Female; Fetal Death; Fetal Heart; Fetal Resorption; Gastrula; Genes, Homeobox; Gestational Age; Morphogenesis; Pregnancy; Pregnancy Complications; Rats; Retinyl Esters; Rhombencephalon; Transcription Factors; Tretinoin; Veins; Vitamin A; Vitamin A Deficiency

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.

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Alleles; Animals; Animals, Congenic; Crosses, Genetic; Embryonic and Fetal Development; Face; Female; Forelimb; Genetic Predisposition to Disease; Genotype; Gestational Age; Hindlimb; Male; Morphogenesis; Polydactyly; Rats; Rats, Inbred BN; Rats, Inbred SHR; Rats, Mutant Strains; Syndrome; Tail; Teratogens; Toes; Tretinoin

A number of studies have suggested that the active derivative of vitamin A, retinoic acid (RA), may be important for early development of mammalian embryos. Severe vitamin A deprivation in rodents results in maternal infertility, precluding a thorough investigation of the role of RA during embryogenesis. Here we show that production of RA by the retinaldehyde dehydrogenase-2 (Raldh2) enzyme is required for mouse embryo survival and early morphogenesis. Raldh2 is an NAD-dependent aldehyde dehydrogenase with high substrate specificity for retinaldehyde. Its pattern of expression during mouse development has suggested that it may be responsible for embryonic RA synthesis. We generated a targeted disruption of the mouse Raldh2 gene and found that Raldh2-/- embryos, which die at midgestation without undergoing axial rotation (body turning), exhibit shortening along the anterioposterior axis and do not form limb buds. Their heart consists of a single, medial, dilated cavity. Their frontonasal region is truncated and their otocysts are severely reduced. These defects result from a block in embryonic RA synthesis, as shown by the lack of activity of RA-responsive transgenes, the altered expression of an RA-target homeobox gene and the near full rescue of the mutant phenotype by maternal RA administration. Our data establish that RA synthesized by the post-implantation mammalian embryo is an essential developmental hormone whose lack leads to early embryo death.

Topics: Abnormalities, Multiple; Aldehyde Oxidoreductases; Animals; Basic Helix-Loop-Helix Transcription Factors; DNA-Binding Proteins; Embryo, Mammalian; Embryonic and Fetal Development; Embryonic Development; Female; Fibroblast Growth Factor 10; Fibroblast Growth Factor 3; Fibroblast Growth Factor 8; Fibroblast Growth Factors; Gene Expression Regulation, Developmental; Homeodomain Proteins; Limb Buds; Male; Mice; Mice, Inbred Strains; Mice, Mutant Strains; Mice, Transgenic; Nerve Tissue Proteins; Otx Transcription Factors; Pregnancy; Proto-Oncogene Proteins; Response Elements; Retinal Dehydrogenase; Trans-Activators; Transcription Factors; Transgenes; Tretinoin

Retinoids long have been implicated in limb development and their endogenous contributions to this process are finally being elucidated. Here we use an established model of retinoid depletion during specific gestational windows to investigate the role of endogenous retinoic acid (RA) in supporting limb outgrowth. Rat embryos were deprived of RA starting at days-postcoitum (dpc) 3.0, 5.5, or 7.0 and harvested at the 35-somite stage (dpc 12-12.5). Although embryos from all these windows possessed many characteristics of gestational retinoid deficiency (frontonasal hypoplasia, straight tail, reduced CRBPI and RAR beta), their limb buds emerged with only modest size reductions. Molecular analysis of RA-deficient limb buds revealed enhanced gli-3 and reduced hoxd-12, hoxd-13, shh, and fgf-4, while fgf-8, en-1, and wnt-7a expression remained unaltered. Occasional posterior truncations were observed at low incidence in the longest deficiency window; otherwise, the deficiency window length had no discernable impact on the severity of these changes. At the 45-somite stage, RA-deficient limbs had additional losses of hoxd-13 and fgf-8, accompanied by a flattened AER, suggestive of an ultimate failure in limb bud outgrowth. Results could not confirm a function for endogenous retinoids in limb initiation, but show they are required to maintain the signaling loops between the developing mesenchyme and AER that govern limb outgrowth after the initial emergence of limb bud.

Topics: Abnormalities, Multiple; Animals; Embryonic and Fetal Development; Embryonic Induction; Female; Fetal Resorption; Gene Expression Regulation, Developmental; Hedgehog Proteins; Homeodomain Proteins; Limb Buds; Pregnancy; Proteins; Rats; Rats, Sprague-Dawley; Signal Transduction; Trans-Activators; Transcription Factors; Tretinoin; Vitamin A Deficiency

The RAR and RXR families of retinoid nuclear receptors each comprise three isotypes (alpha, beta and gamma). In vitro, RARs bind to their cognate DNA response elements as heterodimers with RXRs. Null mutations of all six isotypes have been generated. The defects displayed by RAR alpha, beta and gamma single null mutant mice are confined to a small subset of the tissues normally expressing these receptors. This discrepancy reflects the existence of a functional redundancy, since RAR double null mutants exhibit congenital malformations in almost every organ system. In particular, most of the structures derived from the mesectoderm are severely affected. Analysis of mutant mice lacking both RARs and RXRs indicates that RXR alpha:RAR gamma heterodimers are instrumental in the patterning of craniofacial skeletal elements, whereas RXR alpha:RAR alpha heterodimers may be preferentially involved in the generation of neural crest cell-derived arterial smooth muscle cells. Both RXR alpha:RAR beta and RXR alpha:RAR gamma heterodimers appear to function during the development of the ocular mesenchyme. Moreover, atavistic reptilian cranial structures are generated in RAR mutants, suggesting that the RA signal has been implicated in the modification of developmental programs in the mesectoderm during evolution.

Topics: Abnormalities, Multiple; Animals; Biological Evolution; Craniofacial Abnormalities; Dimerization; Ectoderm; Eye; Facial Bones; Mesoderm; Mice; Mice, Mutant Strains; Muscle, Smooth, Vascular; Neural Crest; Odontogenesis; Receptors, Retinoic Acid; Retinoid X Receptors; Skull; Thymus Gland; Transcription Factors; Tretinoin

Topics: Abnormalities, Multiple; Administration, Topical; Dermatologic Agents; Female; Humans; Infant, Newborn; Pregnancy; Tretinoin

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Animals; Crosses, Genetic; Genetic Carrier Screening; Hindlimb; Inbreeding; Polydactyly; Rats; Rats, Inbred BN; Rats, Inbred Lew; Rats, Mutant Strains; Recombination, Genetic; Syndrome; Teratogens; Tretinoin

The growth and differentiation factor transforming growth factor-beta2 (TGFbeta2) is thought to play important roles in multiple developmental processes. Targeted disruption of the TGFbeta2 gene was undertaken to determine its essential role in vivo. TGFbeta2-null mice exhibit perinatal mortality and a wide range of developmental defects for a single gene disruption. These include cardiac, lung, craniofacial, limb, spinal column, eye, inner ear and urogenital defects. The developmental processes most commonly involved in the affected tissues include epithelial-mesenchymal interactions, cell growth, extracellular matrix production and tissue remodeling. In addition, many affected tissues have neural crest-derived components and simulate neural crest deficiencies. There is no phenotypic overlap with TGFbeta1- and TGFbeta3-null mice indicating numerous non-compensated functions between the TGFbeta isoforms.

Topics: Abnormalities, Multiple; Animals; Bone and Bones; Cleft Palate; Craniofacial Abnormalities; Cyanosis; Ear, Inner; Embryonic Induction; Epithelium; Eye Abnormalities; Genes, Homeobox; Heart Defects, Congenital; Mesoderm; Mice; Mice, Inbred C57BL; Mice, Knockout; Phenotype; Transforming Growth Factor beta; Tretinoin; Urogenital Abnormalities

Both retinoid receptor null mutants and classic nutritional deficiency studies have demonstrated that retinoids are essential for the normal development of diverse embryonic structures (e.g. eye, heart, nervous system, urogenital tract). Detailed analysis of retinoid-modulated events is hampered by several limitations of these models, including that deficiency or null mutation is present throughout gestation, making it difficult to isolate primary effects, and preventing analysis beyond embryolethality. We developed a mammalian model in which retinoid-dependent events are documented during distinct targeted windows of embryogenesis. This was accomplished through the production of vitamin A-depleted (VAD) female rats maintained on sufficient oral retinoic acid (RA) for growth and fertility. After mating to normal males, these RA-sufficient/VAD females were given oral RA doses which allowed for gestation in an RA-sufficient state; embryogenesis proceeded normally until retinoids were withdrawn dietarily to produce a sudden, acute retinoid deficiency during a selected gestational window. In this trial, final RA doses were administered on E11.5, vehicle at E12.5, and embryos analyzed on E13.5; during this 48 hour window, the last RA dose was metabolized and embryos progressed in a retinoid-deficient state. RA-sufficient embryos were normal. Retinoid-depleted embryos exhibited specific malformations of the face, neural crest, eyes, heart, and nervous system. Some defects were phenocopies of those seen in null mutant mice for RXR alpha(-/-), RXR alpha(-/-)/RAR alpha(-/-), and RAR alpha(-/-)/RAR gamma(-/-), confirming that RA transactivation of its nuclear receptors is essential for normal embryogenesis. Other defects were unique to this deficiency model, showing that complete ligand 'knock-out' is required to see those retinoid-dependent events previously concealed by receptor functional redundancy, and reinforcing that retinoid receptors have separate yet overlapping contributions in the embryo. This model allows for precise targeting of retinoid form and deficiency to specific developmental windows, and will facilitate studies of distinct temporal events.

Topics: Abnormalities, Multiple; Animals; Diet; Embryo Implantation; Embryonic and Fetal Development; Eye Abnormalities; Female; Liver; Nervous System; Nervous System Malformations; Neural Crest; Pregnancy; Rats; Rats, Mutant Strains; Rats, Sprague-Dawley; Receptors, Retinoic Acid; Retinoids; Tretinoin; Vitamin A Deficiency

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Animals; Cloning, Molecular; Embryonic and Fetal Development; Exons; Female; Genomic Library; Genotype; Limb Deformities, Congenital; Male; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Mice, Transgenic; Placenta; Pregnancy; Receptors, Retinoic Acid; Recombinant Fusion Proteins; Signal Transduction; Tretinoin

Retinoic acid, an oxidative metabolite of vitamin A, is involved in the control of many biological processes including embryonic development. Excess as well as deficiency of retinoids were found to be teratogenic. The effects of retinoids in normal as well as abnormal development may be mediated by two members of retinoid receptors, the RAR's and RXR's, which exhibit a specific temporal and spatial expression during development. The significance of the retinoid receptors was investigated here by studying the teratogenic effects of retinoid ligands with relative selectivity for binding and transactivation of the retinoic acid receptors RAR alpha, RAR beta and RAR gamma. Pregnant NMRI mice were administered 5 or 15 mg/kg of CD 336 (Am 580) (alpha-ligand), CD 2019 (beta-ligand), CD 437 (gamma-ligand) or 37.5 mg/kg all-trans-retinoic acid in 25% Cremophor EL on day 8.25 or day 11 of gestation by gastric intubation. External, visceral and skeletal malformations were observed on day 18 of gestation. The order of teratogenic potency was: alpha-ligand > beta-ligand > gamma-ligand. In addition, these retinoids also produced a different spectrum of defects. The alpha-ligand induced the most varied defects including severe ear, mandible, and limb malformations. The beta-ligand induced defects of the urinary system and liver in greater frequency than expected from its relative potency. The gamma-ligand preferentially induced ossification deficiencies and defects of the sternebrae and vertebral body. Our results show that these three retinoids, which were previously demonstrated to exhibit retinoid-like activities in several systems, exert differing teratogenic activities, in regard to both potency and regioselectivity: we hypothesize that the relative selectivity for binding and transactivation of the three retinoic acid receptors could possibly be related to the differences of teratogenic effects observed in this study. The low potency of the gamma-ligand may lead the way to interesting new retinoids with improved therapeutic ratio.

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Administration, Oral; Animals; Benzoates; Bone and Bones; Central Nervous System; Digestive System Abnormalities; Female; Mice; Naphthalenes; Pregnancy; Pregnancy Outcome; Receptors, Retinoic Acid; Retinoids; Tetrahydronaphthalenes; Tretinoin; Urogenital Abnormalities

Retinoic acid, the morphogenic derivative of vitamin A, has been shown to alter patterns of neurulation and to regulate the expression of many genes involved in central nervous system development. Retinoid toxicity can result in craniofacial, limb, digit, heart and urogenital abnormalities. Hydrocephalus, due to increased ventricular size and/or decreased size of the hind- or forebrain, occurs frequently. Comparison of the frequency and type of congenital anomalies in extended pedigrees of 12 Ashkenazi probands with schizophrenia and seven normal Ashkenazi control probands indicates that relatives of the schizophrenic probands present a gamut of both minor and major congenital anomalies similar to, but less severe than, those caused by retinoid excess or deficiency, and at a frequency significantly greater than in control pedigrees. Within schizophrenic pedigrees, those diagnosed with schizophrenia spectrum illnesses are more likely to present such anomalies than are non-spectrum members. Retinoic acid receptors are present in all parts of the cranial region and delivery of retinoids is exquisitely controlled throughout embryonic and fetal development. Alterations in the functioning of the retinoid cascade may have profound implications for neurodevelopmental disorders like schizophrenia.

Topics: Abnormalities, Multiple; Brain; Consanguinity; Female; Gene Expression; Humans; Jews; Male; Neurocognitive Disorders; Pedigree; Receptors, Retinoic Acid; Risk Factors; Schizophrenia; Tretinoin

This study was designed to examine the developmental dose response for all-trans retinoic acid (TRA) administered at presomite stages in mouse embryos. Previous studies using hamsters [Shenefelt (1972) Teratology 5:103-118] have shown that developmental stages corresponding to those present early on gestational day (GD) 7 in mice are most sensitive to retinoid-induced teratogenesis. Our preliminary studies showed that at this treatment time, gavage dosages of 7.5 mg/kg maternal body weight administered to C57B1/6N mice, an inbred strain, resulted in severe craniofacial malformations representing the holoprosencephaly, aprosencephaly spectrum. Additionally, in an outbred mouse strain, CD-1, exencephaly was induced by dosages of 2.5 mg/kg TRA and above. Readily detectable abnormalities of the eyes, including anophthalmia and severe microphthalmia and iridial colobomata, were induced by even lower doses cf TRA in the C57B1/6N strain. Incidences of micro/anophthalamia were 6.7%, 8.1%, 12.9%, and 32.4% at 0, 0.313, 0.625, and 1.25 mg/kg, respectively. The dosages required to induce significant incidences of exencephaly (2.5 mg/kg) and severe ocular abnormalities (1.25 mg/kg) on GD 7 in mice are approximately 50-100-fold less than those that are commonly used to examine the teratogenicity of this compound at later developmental stages in this species. The trend toward an increase in the incidence of severe ocular malformations at the lowest dose examined and the fact that subtle ocular malformations were not taken into account for this study suggest that even lower dosages may be effective.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Animals; Cricetinae; Dose-Response Relationship, Drug; Embryo, Mammalian; Female; Mice; Mice, Inbred C57BL; Microscopy, Electron, Scanning; Pregnancy; Teratogens; Tretinoin

Numerous congenital malformations have been observed in fetuses of vitamin A-deficient (VAD) dams [Wilson, J. G., Roth, C. B., Warkany, J., (1953), Am. J. Anat. 92, 189-217]. Previous studies of retinoic acid receptor (RAR) mutant mice have not revealed any of these malformations [Li, E., Sucov, H. M., Lee, K.-F., Evans, R. M., Jaenisch, R. (1993) Proc. Natl. Acad. Sci. USA 90, 1590-1594; Lohnes, D., Kastner, P., Dierich, A., Mark, M., LeMeur, M., Chambon, P. (1993) Cell 73, 643-658; Lufkin, T., Lohnes, D., Mark, M., Dierich, A., Gorry, P., Gaub, M. P., Lemeur, M., Chambon, P. (1993) Proc. Natl. Acad. Sci. USA 90, 7225-7229; Mendelsohn, C., Mark, M., Dollé, P., Dierich, A., Gaub, M.P., Krust, A., Lampron, C., Chambon, P. (1994a) Dev. Biol. in press], suggesting either that there is a considerable functional redundancy among members of the RAR family during ontogenesis or that the RARs are not essential transducers of the retinoid signal in vivo. In order to discriminate between these possibilities, we have generated a series of RAR compound null mutants. These RAR double mutants invariably died either in utero or shortly after birth and presented a number of congenital abnormalities, which are reported in this and in the accompanying study. We describe here multiple eye abnormalities which are found in various RAR double mutant fetuses and are similar to those previously seen in VAD fetuses. Interestingly, we found further abnormalities not previously reported in VAD fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Abnormalities, Multiple; Animals; Bone and Bones; Brain; Extremities; Eye; Eye Abnormalities; Facial Bones; Genotype; Limb Deformities, Congenital; Mice; Mice, Mutant Strains; Morphogenesis; Phenotype; Receptors, Retinoic Acid; Skull; Tretinoin

Compound null mutations of retinoic acid receptor (RAR) genes lead to lethality in utero or shortly after birth and to numerous developmental abnormalities. In the accompanying paper (Lohnes, D., Mark., M., Mendelsohn, C., Dollé, P., Dierich, A., Gorry, Ph., Gansmuller, A. and Chambon, P. (1994). Development 120, 2723-2748), we describe malformations of the head, vertebrae and limbs which, with the notable exception of the eye defects, were not observed in the offspring of vitamin A-deficient (VAD) dams. We report here abnormalities in the neck, trunk and abdominal regions of RAR double mutant mice, which include: (i) the entire respiratory tract, (ii) the heart, its outlow tract and the great vessels located near the heart, (iii) the thymus, thyroid and parathyroid glands, (iv) the diaphragm, (v) the genito-urinary system, and (vi) the lower digestive tract. A majority of these abnormalities recapitulate those observed in the fetal VAD syndrome described by Joseph Warkany's group more than fourty years ago [Wilson, J. G., Roth, C. B. and Warkany, J. (1953) Am. J. Anat., 92, 189-217; and refs therein]. Our results clearly demonstrate that RARs are essential for vertebrate ontogenesis and therefore that retinoic acid is the active retinoid, which is required at several stages of the development of numerous tissues and organs. We discuss several possibilities that may account for the apparent functional redundancy observed amongst retinoic acid receptors during embryogenesis.

Topics: Abnormalities, Multiple; Animals; Cardiovascular System; Endocrine Glands; Genitalia; Heart Defects, Congenital; Kidney; Lung; Mice; Mice, Mutant Strains; Morphogenesis; Receptors, Retinoic Acid; Trachea; Tretinoin

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Acne Vulgaris; Administration, Topical; Female; Humans; Infant, Newborn; Pregnancy; Pregnancy Complications; Tretinoin

Null mutant mice for retinoic acid receptor gamma 2 (RAR gamma 2) or all RAR gamma isoforms were generated. RAR gamma 2 mutants appeared normal, whereas RAR gamma mutants exhibited growth deficiency, early lethality, and male sterility due to squamous metaplasia of the seminal vesicles and prostate. These defects were previously observed in vitamin A-deficient animals and could be prevented by RA administration, demonstrating that RAR gamma mediates some of the retinoid signal in vivo. Congenital defects included Harderian gland agenesis, tracheal cartilage malformations, and homeotic transformations along the rostral axial skeleton, establishing a direct link between RA and patterning of the axial skeleton. We also show that in utero RA-induced lumbosacral truncations are mediated by RAR gamma. The observed RAR gamma null phenotype suggests a high degree of functional redundancy among the RARs. The variable penetrance of some of the observed defects is discussed in light of this redundancy and stochastic variation of gene activity.

Topics: Abnormalities, Multiple; Animals; Base Sequence; Bone and Bones; Carrier Proteins; Cartilage; Embryonic and Fetal Development; Female; Genes, Lethal; Growth Disorders; Homozygote; Male; Mice; Mice, Mutant Strains; Molecular Sequence Data; Receptors, Retinoic Acid; Recombination, Genetic; Tretinoin; Vitamin A Deficiency

A case of retinoic acid embryopathy which was retrospectively diagnosed after delivery is presented. The affected fetus was exposed to the drug during the first month of pregnancy and second-trimester sonographic examination showed hydrocephalus and cardiac malformation. The diagnosis was made on the basis of autopsy findings and genetic enquiry.

Topics: Abnormalities, Multiple; Abortion, Therapeutic; Adult; Facial Bones; Female; Heart Defects, Congenital; Humans; Hydrocephalus; Maternal-Fetal Exchange; Pregnancy; Pregnancy Trimester, Second; Tretinoin; Ultrasonography, Prenatal

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Adult; Female; Humans; Infant, Newborn; Male; Penis; Pregnancy; Pregnancy Complications; Psoriasis; Teratogens; Tretinoin

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Female; Humans; Infant, Newborn; Isotretinoin; Male; New Jersey; Teratogens; Tretinoin; United States; United States Food and Drug Administration

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Female; Humans; Infant, Newborn; Isotretinoin; Male; New Jersey; Teratogens; Tretinoin; United States; United States Food and Drug Administration

Topics: Abnormalities, Multiple; Humans; Infant; Isotretinoin; Phenotype; Syndrome; Tretinoin

Vitamin A and vitamin A derivatives have been described as etiologic factors for a number of congenital malformations. Two infants are presented with major auricular malformations including anotia and severe microtia. The infants were products of a pregnancy complicated by Accutane ingestion during the first trimester. Both infants had associated central nervous system malformations. With the increasing use of Accutane for the treatment of cystic acne in young women of child-bearing age, the dangers of teratogenesis in the head and neck area are greatly increased. This presentation will review two such cases as well as give an overview of the embryogenesis and teratogenesis of the auricle.

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Acne Vulgaris; Adult; Ear, External; Female; Humans; Infant, Newborn; Isotretinoin; Male; Teratogens; Tretinoin

Although most known human teratogens often produce a combination of birth defects in an affected infant, surveillance programs aimed at detecting epidemics of birth defects usually only monitor rates of individual defects. A drawback to this approach is that an increase in the rate of infants affected with a specific combination of defects may lead to little or no increase in the rates of component defects. Using the Poisson distribution, we show that, compared with monitoring for individual defects, monitoring for combinations of two and three defects may require fewer numbers of births to detect an epidemic. In general, an increase can be detected more rapidly by monitoring the rates of defect combinations than by monitoring the rates of individual defects if most affected infants have combinations of defects rather than isolated defects. For example, in the case of Congenital rubella syndrome (CRS), monitoring for the combination of cataracts with deafness and/or patent ductus arteriosus could have led to earlier detection of an epidemic than could monitoring for cataracts alone. In contrast, in the case of thalidomide embryopathy, monitoring for reduction defects of upper limbs in combination with reduction defects of lower limbs and/or microtia/anotia would not have led to earlier detection of an epidemic than would monitoring for reduction defects of upper limbs alone. This is due mainly to the low frequency of defect combinations among affected cases. When used with regular monitoring for individual defects, surveillance of defect combinations can enhance the ability of monitoring programs to detect epidemics of birth defects.

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Biometry; Female; Humans; Pregnancy; Rubella; Teratogens; Thalidomide; Tretinoin; United States

Topics: Abnormalities, Multiple; Brain; Brain Diseases; Humans; Isotretinoin; Syndrome; Tomography, X-Ray Computed; Tretinoin

The teratogenicity of vitamin A has been repeatedly reported in the literature and confirmed on the basis of several cases of adverse pregnancy outcome associated with maternal isotretinoin exposure. We report a case which shows a striking similarity with this syndrome, but the child was born to a mother who took a normal supplementation of vitamin A during pregnancy. The differential diagnosis is discussed.

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Adult; Diagnosis, Differential; Female; Humans; Infant, Newborn; Isotretinoin; Phenotype; Pregnancy; Tretinoin; Vitamin A; Vitamins

Isotretinoin, a drug used for the treatment of acne, has been shown to have teratogenic effects. We report an additional case of isotretinoin teratogenicity in which the patient had agenesis of the cerebellar vermis, multiple leptomeningeal neuroglial heterotopias, hydrocephalus, and abnormalities of the corticospinal tracts. These findings are related to those reported previously.

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Acne Vulgaris; Adult; Brain; Female; Humans; Infant, Newborn; Isotretinoin; Teratogens; Tretinoin

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Adolescent; Cerebellum; Ear, External; Face; Female; Humans; Infant, Newborn; Isotretinoin; Male; Pregnancy; Tretinoin

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Female; Humans; Infant, Newborn; Isotretinoin; Maternal-Fetal Exchange; Pregnancy; Tretinoin

13-cis-Retinoic acid, retinyl-mthyl-ether, retinyl-phenyl-ether, retinyl-thio-ether and axerophthene each induced dose-dependent sister-chromatid exchanges (SCE) in human diploid fibroblasts. The functional relationship between retinoid concentration and SCE rate was similar in each of the 5 retinoids tested. The relationship reached a plateau at concentrations exceeding 8 micrograms/ml. alpha-Naphthoflavone (ANF), an inhibitor of P448-dependent mono-oxygenase, prevented the retinoid-induced increase of the SCE rate, but had no inhibitory effect in the presence of 4-nitroquinoline-1-oxide, an ultimate carcinogen. ANF did not reduce the spontaneously increased SCE rate in fibroblasts of patients with Bloom's syndrome. Retinoids failed to induce SCE in V79 Chinese hamster cells, which lack mono-oxygenase. Thus, we conclude that the retinoid-induced SCE rate increases independently of structural changes in the molecular side-chain ad that a metabolic activation of retinoids is required for SCE induction by cytochrome P448-dependent mono-oxygenase.

Topics: Abnormalities, Multiple; Animals; Benzoflavones; Biotransformation; Cell Line; Cricetinae; Cricetulus; Crossing Over, Genetic; Cytochrome P-450 CYP1A2; Cytochromes; Dose-Response Relationship, Drug; Fibroblasts; Humans; Isotretinoin; Mixed Function Oxygenases; Sister Chromatid Exchange; Skin; Structure-Activity Relationship; Telangiectasis; Tretinoin; Vitamin A

The teratogenic effects of retinoic acid, the alcohol-soluble acid form of vitamin A, on the craniofacial complex of 11 macaque (Macaca nemestrina) whose mothers had received the compound from days 20 to 44 are described. The fetuses ranged in gestational age from 81 to 185 days and exhibited features of the so-called retinoic acid syndrome (RAS). The syndrome includes both craniofacial defects and postcranial anomalies of the musculoskeletal and urogenital systems. The craniofacial anomalies were described with reference to gross external appearance and radiographic observations. The most frequent findings were cleft palate, malformed ears, hypertelorism, exophthalmos, hypoplasia of the bone of the mid-face and mandible, a curvature of the inferior border of the mandible, retrognathia, and distortion of the cranium. Lateral cephalograms on nine animals of the RAS sample were measured using six linear dimensions which define the cranial base, face height, palatal length, and mandibular length. The measurements were plotted relative to normal curves which describe growth of the dimensions through the macaque fetal period. For their age, the abnormal animals were small in the craniofacial region. The same measurements were then plotted relative to the size of the fetus, to investigate the possibility of a differential response of the various craniofacial areas to the teratogen. Mandibular length and anterior cranial base were the most reduced dimensions, followed by anterior and posterior face height, with palatal length the least affected. Comparison of the features of the RAS syndrome in the macaque fetus with those reported for various human mandibulofacial dysostosis syndromes yields similarities, but there are enough differences to indicate that the syndromes are not identical in the two species. The utility of the approach used, wherein several craniofacial dimensions of the abnormal are assessed relative to normal growth curves and relative to body size, is emphasized.

Topics: Abnormalities, Drug-Induced; Abnormalities, Multiple; Animals; Cephalometry; Facial Bones; Female; Fetus; Macaca nemestrina; Pregnancy; Radiography; Skull; Tretinoin