transforming-growth-factor-beta and Fetal-Death

N629D KCNH2 is a human missense long-QT2 mutation. Previously, we reported that the N629D/N629D mutation embryos disrupted cardiac looping, right ventricle development, and ablated IKr activity at E9.5. The present study evaluates the role of KCNH2 in vasculogenesis.. N629D/N629D yolk sac vessels and aorta consist of sinusoids without normal arborization. Isolated E9.5 +/+ first branchial arches showed normal outgrowth of mouse ERG-positive/α-smooth muscle actin coimmunolocalized cells; however, outgrowth was grossly reduced in N629D/N629D. N629D/N629D aortas showed fewer α-smooth muscle actin positive cells that were not coimmunolocalized with mouse ERG cells. Transforming growth factor-β treatment of isolated N629D/N629D embryoid bodies partially rescued this phenotype. Cultured N629D/N629D embryos recapitulate the same cardiovascular phenotypes as seen in vivo. Transforming growth factor-β treatment significantly rescued these embryonic phenotypes. Both in vivo and in vitro, dofetilide treatment, over a narrow window of time, entirely recapitulated the N629D/N629D fetal phenotypes. Exogenous transforming growth factor-β treatment also rescued the dofetilide-induced phenotype toward normal.. Loss of function of KCNH2 mutations results in defects in cardiogenesis and vasculogenesis. Because many medications inadvertently block the KCNH2 potassium current, these novel findings seem to have clinical relevance.

Topics: Abnormalities, Drug-Induced; Animals; Cells, Cultured; Embryo Culture Techniques; Embryonic Stem Cells; ERG1 Potassium Channel; Ether-A-Go-Go Potassium Channels; Fetal Death; Gene Expression Regulation, Developmental; Genotype; Heart Defects, Congenital; Humans; Mice, 129 Strain; Mice, Transgenic; Morphogenesis; Mutation, Missense; Neovascularization, Physiologic; Phenethylamines; Phenotype; Potassium Channel Blockers; Signal Transduction; Sulfonamides; Transforming Growth Factor beta; Vascular Malformations

Topics: Abnormalities, Drug-Induced; Animals; Embryonic Stem Cells; ERG1 Potassium Channel; Ether-A-Go-Go Potassium Channels; Fetal Death; Heart Defects, Congenital; Humans; Mutation, Missense; Neovascularization, Physiologic; Phenethylamines; Potassium Channel Blockers; Sulfonamides; Transforming Growth Factor beta; Vascular Malformations

Hepatoma-derived growth factor (HDGF) related protein 2 (HRP2) and lens epithelium-derived growth factor (LEDGF)/p75 are closely related members of the HRP2 protein family. LEDGF/p75 has been implicated in numerous human pathologies including cancer, autoimmunity, and infectious disease. Knockout of the Psip1 gene, which encodes for LEDGF/p75 and the shorter LEDGF/p52 isoform, was previously shown to cause perinatal lethality in mice. The function of HRP2 was by contrast largely unknown. To learn about the role of HRP2 in development, we knocked out the Hdgfrp2 gene, which encodes for HRP2, in both normal and Psip1 knockout mice. Hdgfrp2 knockout mice developed normally and were fertile. By contrast, the double deficient mice died at approximate embryonic day (E) 13.5. Histological examination revealed ventricular septal defect (VSD) associated with E14.5 double knockout embryos. To investigate the underlying molecular mechanism(s), RNA recovered from ventricular tissue was subjected to RNA-sequencing on the Illumina platform. Bioinformatic analysis revealed several genes and biological pathways that were significantly deregulated by the Psip1 knockout and/or Psip1/Hdgfrp2 double knockout. Among the dozen genes known to encode for LEDGF/p75 binding factors, only the expression of Nova1, which encodes an RNA splicing factor, was significantly deregulated by the knockouts. However the expression of other RNA splicing factors, including the LEDGF/p52-interacting protein ASF/SF2, was not significantly altered, indicating that deregulation of global RNA splicing was not a driving factor in the pathology of the VSD. Tumor growth factor (Tgf) β-signaling, which plays a key role in cardiac morphogenesis during development, was the only pathway significantly deregulated by the double knockout as compared to control and Psip1 knockout samples. We accordingly speculate that deregulated Tgf-β signaling was a contributing factor to the VSD and prenatal lethality of Psip1/Hdgfrp2 double-deficient mice.

Topics: Adaptor Proteins, Signal Transducing; Animals; Female; Fetal Death; Gene Expression Regulation, Developmental; Heart; Heart Defects, Congenital; Heart Septal Defects, Ventricular; Intercellular Signaling Peptides and Proteins; Mice, Inbred C57BL; Mice, Knockout; Myocardium; Neuro-Oncological Ventral Antigen; RNA-Binding Proteins; Transcription Factors; Transforming Growth Factor beta

One of the mysteries of pregnancy is why a mother does not reject her fetuses. Cytokine-modulation of maternal-fetal interactions is likely to be important. However, mice deficient in transforming growth factor-beta1 (TGF beta 1) and other cytokines are able to breed, bringing this hypothesis into question. The phenotype of TGF beta 1 null-mutant mice varies with genetic background. We report here that, in outbred mice, the loss of TGF beta 1-deficient embryos is influenced by the parity of their mother. This is consistent with the loss of mutants being due to immune rejection. An inbred line of TGF beta 1(+/-) mice that supported TGF beta 1-deficient fetuses had high levels of TGF beta 1 in their plasma. Analysis of the amniotic fluids in this line indicated that biologically relevant levels of maternal TGF beta 1 were present in the TGF beta 1(-/-) fetuses. These data are consistent with maternal and fetal TGF beta 1 interacting to maintain pregnancy, within immune-competent mothers.

Topics: Amniotic Fluid; Animals; Female; Fetal Blood; Fetal Death; Maternal-Fetal Exchange; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Nude; Parity; Pregnancy; Pregnancy Maintenance; Transforming Growth Factor beta; Transforming Growth Factor beta1

Serrated adenomas, hyperplastic polyps, and admixed hyperplastic/adenomatous polyps form a distinct group of colorectal tumors, the molecular genetic basis of which is still poorly understood. We describe a novel mouse model for serrated adenomas and mixed polyposis, here referred to as Sad (serrated adenomas), caused by a spontaneously risen splice site mutation in the murine Smad4 gene. The Sad chromosomal region was identified by genetic linkage and loss of heterozygosity (LOH) analysis. Subsequently, several candidate genes were investigated by expression and mutation analysis. By use of genetic linkage and LOH analysis, we mapped the Sad candidate to mouse chromosome 18, 44-48 cM, syntenic to human chromosome band 18q21. Within this chromosomal interval, the Smad2, Smad4, and Smad7 genes were analyzed for the presence of a disease-causing mutation in affected animals. A single nucleotide (nt) deletion was identified in the intron 5/exon 6 splice acceptor site of the Smad4 gene. The single base deletion results in a frameshift and an early termination codon through activation of a cryptic splice site 4 nt downstream in exon 6. The resulting mRNA is unstable, and the Sad mutation is thus likely to represent a null allele. Identification of a Smad4 mutation in the Sad mouse model provides further support for the involvement of the Smad genes, and thus the TGFB pathway, in the serrated/hyperplastic route to colorectal cancer.

Topics: Adenomatous Polyps; Animals; Cell Line; Colonic Polyps; Colorectal Neoplasms; Disease Models, Animal; DNA-Binding Proteins; Female; Fetal Death; Gene Expression Profiling; Genes, Lethal; Homozygote; Hyperplasia; Loss of Heterozygosity; Male; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; RNA Splice Sites; Sequence Deletion; Signal Transduction; Smad4 Protein; Trans-Activators; Transforming Growth Factor beta

Given all known biological activities, it is anticipated that transforming growth factors beta (TGF-betas) play important roles in many different developmental processes. As all three TGF-beta isoforms display overlapping expression patterns, deletion of one TGF-beta isoform might be compensated for by another. In the present study, targeted disruption of both Tgfbeta2 and Tgfbeta3 genes was undertaken to circumvent this problem and determine the essential roles of TGF-beta2 and TGF-beta3 in vivo. Tgfbeta2(-/-) Tgfbeta3(-/-) double knockout mice and their three-allelic Tgfbeta2(-/-) Tgfbeta3(+/-) littermates display a lack of distal parts of the rib, a lack of sternal primordia, and failure in ventral body wall closure, leading to an extrathoracic position of the heart and extrusion of the liver. In addition, abnormalities in connective tissue composition and an early embryonic lethality [around embryonic day (E) 15.5] are seen. In contrast, Tgfbeta2 (+/-) Tgfbeta3 (-/-) littermates show normal rib and sternum development, normal anterior body wall fusion, and are still alive on E18.5. TGF-beta2 is already known to play a role in skeletal and craniofacial development. The results presented here show that beyond this: (a). TGF-betas obviously play a fundamental role in midline fusion and (b). the Tgfbeta2 gene seems to play a more important role in mediating developmental processes than the Tgfbeta3 gene, since Tgfbeta2 (+/-) Tgfbeta3 (-/-) mutants - in contrast to their Tgfbeta2(-/-) Tgfbeta3 (+)(/-) littermates - do not display severe malformations.

Topics: Abnormalities, Multiple; Animals; Body Patterning; Fetal Death; Gene Expression Regulation, Developmental; Genes, Lethal; Gestational Age; Heterozygote; Mice; Mice, Inbred Strains; Mice, Knockout; Morphogenesis; Transforming Growth Factor beta; Transforming Growth Factor beta2; Transforming Growth Factor beta3

Positional information in the dorsoventral axis of the Drosophila embryo is encoded by a BMP activity gradient formed by synergistic signaling between the BMP family members Decapentaplegic (DPP) and Screw (SCW). short gastrulation (sog), which is functionally homologous to Xenopus Chordin, is expressed in the ventrolateral regions of the embryo and has been shown to act as a local antagonist of BMP signaling. Here we demonstrate that SOG has a second function, which is to promote BMP signaling on the dorsal side of the embryo. We show that a weak, homozygous-viable sog mutant is enhanced to lethality by reduction in the activities of the Smad family members Mad or Medea, and that the lethality is caused by defects in the molecular specification and subsequent cellular differentiation of the dorsal-most cell type, the amnioserosa. While previous data had suggested that the negative function of SOG is directed against SCW, we present data that suggests that the positive activity of SOG is directed towards DPP. We demonstrate that Chordin shares the same apparent ligand specificity as does SOG, preferentially inhibiting SCW but not DPP activity. However, in Drosophila assays Chordin does not have the same capacity to elevate BMP signaling as does SOG, identifying a functional difference in the otherwise well conserved process of dorsoventral pattern formation in arthropods and chordates.

Topics: Animals; Body Patterning; Bone Morphogenetic Proteins; DNA-Binding Proteins; Drosophila; Drosophila Proteins; Embryo, Nonmammalian; Female; Fetal Death; Gastrula; Gene Dosage; Gene Expression Regulation, Developmental; Glycoproteins; Homeodomain Proteins; Insect Proteins; Intercellular Signaling Peptides and Proteins; Male; Mutation; Proteins; Repressor Proteins; Signal Transduction; Smad4 Protein; Trans-Activators; Transcription Factors; Transforming Growth Factor beta

Transforming growth factor-beta(1) (TGF-beta(1)) is expressed in the adult and embryonic vasculature; however, the biological consequences of increased vascular TGF-beta(1) expression remain controversial. To establish an experimental setting for investigating the role of increased TGF-beta(1) in vascular development and disease, we generated transgenic mice in which a cDNA encoding a constitutively active form of TGF-beta(1) is expressed from the SM22alpha promoter. This promoter fragment directs transgene expression to smooth muscle cells of large arteries in late-term embryos and postnatal mice. We confirmed the anticipated pattern of SM22alpha-directed transgene expression (heart, somites, and vasculature of the embryo and yolk sac) in embryos carrying an SM22alpha-beta-galactosidase transgene. SM22alpha- beta-galactosidase transgenic mice were born at the expected frequency (13%); however, nearly all SM22alpha-TGF-beta(1) transgenic mice died before E11.5. SM22alpha-TGF-beta(1) transgenic embryos identified at E8.5 to E10.5 had growth retardation and both gross and microscopic abnormalities of the yolk sac vasculature. Overexpression of TGF-beta(1) from the SM22alpha promoter is lethal at E8.5 to E10.5, most likely because of yolk sac insufficiency. Investigation of the consequences of increased vascular TGF-beta(1) expression in adults may require a conditional transgenic approach. Moreover, because the SM22alpha promoter drives transgene expression in the yolk sac vasculature at a time when embryonic survival is dependent on yolk sac function, use of the SM22alpha promoter to drive expression of "vasculoactive" transgenes may be particularly likely to cause embryonic death.

Topics: Animals; Blood Vessels; Cardiovascular System; Embryo, Mammalian; Fetal Death; Fetal Resorption; Gene Expression; Heart; Hematopoietic Stem Cells; Mice; Mice, Transgenic; Microfilament Proteins; Muscle Proteins; Promoter Regions, Genetic; Transforming Growth Factor beta; Transgenes; Yolk Sac

FKBP12, a cis-trans prolyl isomerase that binds the immunosuppressants FK506 and rapamycin, is ubiquitously expressed and interacts with proteins in several intracellular signal transduction systems. Although FKBP12 interacts with the cytoplasmic domains of type I receptors of the transforming growth factor-beta (TGF-beta) superfamily in vitro, the function of FKBP12 in TGF-beta superfamily signalling is controversial. FKBP12 also physically interacts stoichiometrically with multiple intracellular calcium release channels including the tetrameric skeletal muscle ryanodine receptor (RyR1). In contrast, the cardiac ryanodine receptor, RyR2, appears to bind selectively the FKBP12 homologue, FKBP12.6. To define the functions of FKBP12 in vivo, we generated mutant mice deficient in FKBP12 using embryonic stem (ES) cell technology. FKBP12-deficient mice have normal skeletal muscle but have severe dilated cardiomyopathy and ventricular septal defects that mimic a human congenital heart disorder, noncompaction of left ventricular myocardium. About 9% of the mutants exhibit exencephaly secondary to a defect in neural tube closure. Physiological studies demonstrate that FKBP12 is dispensable for TGF-beta-mediated signalling, but modulates the calcium release activity of both skeletal and cardiac ryanodine receptors.

Topics: Abnormalities, Multiple; Activins; Amino Acid Isomerases; Animals; Brain; Cardiomyopathy, Dilated; Carrier Proteins; DNA-Binding Proteins; Female; Fetal Death; Gene Deletion; Heart Defects, Congenital; Heart Septal Defects; Heat-Shock Proteins; Inhibins; Male; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Ryanodine Receptor Calcium Release Channel; Signal Transduction; Tacrolimus Binding Proteins; Transforming Growth Factor beta

Signalling by the transforming growth factor-beta (TGF-beta) superfamily of proteins depends on the phosphorylation and activation of SMAD proteins by heteromeric complexes of ligand-specific type I and type II receptors with serine/threonine-kinase activity. The vertebrate SMAD family includes at least nine members, of which Smad2 has been shown to mediate signalling by activin and TGF-beta. In Xenopus, Smad2 can induce dorsal mesoderm, mimicking Vg-1, activin and nodal. Here we investigate the function of Smad2 in mammalian development by generating two independent Smad2 mutant alleles in mice by gene targeting. We show that homozygous mutant embryos fail to form an organized egg cylinder and lack mesoderm, like mutant mice lacking nodal or ActRIB, the gene encoding the activin type-I receptor. About 20 per cent of Smad2 heterozygous embryos have severe gastrulation defects and lack mandibles or eyes, indicating that the gene dosage of Smad2 is critical for signalling. Mice trans-heterozygous for both Smad2 and nodal mutations display a range of phenotypes, including gastrulation defects, complex craniofacial abnormalities such as cyclopia, and defects in left-right patterning, indicating that Smad2 may mediate nodal signalling in these developmental processes. Our results show that Smad2 function is essential for early development and for several patterning processes in mice.

Topics: Abnormalities, Multiple; Animals; Body Patterning; Cell Line; Cloning, Molecular; Craniofacial Abnormalities; DNA-Binding Proteins; Embryo, Mammalian; Embryonic and Fetal Development; Facial Bones; Fetal Death; Gastrula; Gene Targeting; Mesoderm; Mice; Mice, Inbred C57BL; Mutagenesis; Nodal Protein; Proteins; Signal Transduction; Skull; Smad2 Protein; Stem Cells; Trans-Activators; Transforming Growth Factor beta

Pregnancy after the onset of scleroderma is uncommon; therefore, placental findings and perinatal outcome have rarely been correlated. The histopathologic features of placentas from 13 pregnancies in eight women with scleroderma were recorded and correlated with the clinical features of the mother and fetus. Adverse perinatal outcome included intrauterine fetal demise in five, and previable or preterm delivery in four. A decidual vasculopathy was seen in 5 of the 13 placentas, four of which were associated with intrauterine fetal demise. Decidual blood vessels in the scleroderma patients were evaluated immunohistochemically for platelet-derived growth factor (PDGF), transforming growth factor beta1 (TGF-beta1), T-helper and T-suppressor lymphocytes, macrophages, immunoglobulin (Ig) M, and IgG, and compared with those from hypertensive and uncomplicated third-trimester pregnancies. The atherotic blood vessels in scleroderma were characterized by mural macrophages and IgM and IgG deposition and were similar to those seen in placentas from hypertensive pregnancies. CD8-positive T cells predominated in normal and hypertensive decidua compared with scleroderma, in which CD4-positive T cells were more frequent. No difference in PDGF or TGF-beta1 staining was found between scleroderma and control groups. In conclusion, decidual vasculopathy is common in scleroderma, is similar to that seen in hypertension, and is associated with poor perinatal outcome. A trend toward a reversed ratio of decidual CD4 to CD8-positive T cells is seen in scleroderma compared with hypertension and uncomplicated pregnancies. PDGF and TGF-beta1 do not appear to be involved in the pathogenesis of decidual vasculopathy in scleroderma.

Topics: Abortion, Spontaneous; Adolescent; Adult; Antigens, CD; Arteriosclerosis; Blood Vessels; CD4-CD8 Ratio; Decidua; Female; Fetal Death; Gestational Age; Humans; Hypertension; Immunoglobulins; Infant, Newborn; Male; Obstetric Labor, Premature; Platelet-Derived Growth Factor; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Scleroderma, Systemic; Transforming Growth Factor beta

The transforming growth factor beta 1 (TGF beta 1) signalling pathway is important in embryogenesis and has been implicated in hereditary haemorrhagic telangiectasia (HHT), atherosclerosis, tumorigenesis and immunomodulation. Therefore, identification of factors which modulate TGF beta 1 bioactivity in vivo is important. On a mixed genetic background, approximately 50% Tgfb1-/- conceptuses die midgestation from defective yolk sac vasculogenesis. The other half are developmentally normal but die three weeks postpartum. Intriguingly, the vascular defects of Tgfb1-/- mice share histological similarities to lesions seen in HHT patients. It has been suggested that dichotomy in Tgfb1-/- lethal phenotypes is due to maternal TGF beta 1 rescue of some, but not all, Tgfb1-/- embryos12. Here we show that the Tgfb1-/- phenotype depends on the genetic background of the conceptus. In NIH/Ola, C57BL/6J/Ola and F1 conceptuses, Tgfb1-/- lethality can be categorized into three developmental classes. A major codominant modifier gene of embryo lethality was mapped to proximal mouse chromosome 5, using a genome scan for non-mendelian distribution of alleles in Tgfb1-/- neonatal animals which survive prenatal lethality. This gene accounts for around three quarters of the genetic effect between mouse strains and can, in part, explain the distribution of the three lethal phenotypes. This approach, using neonatal DNA samples, is generally applicable to identification of loci that influence the effect of early embryonic lethal mutations, thus furthering knowledge of genetic interactions that occur during early mammalian development in vivo.

Topics: Animals; Chromosome Mapping; Crosses, Genetic; Embryonic and Fetal Development; Fetal Death; Genes, Lethal; Hematopoiesis; Mice; Mice, Inbred C57BL; Mice, Knockout; Microsatellite Repeats; Phenotype; Transforming Growth Factor beta; Yolk Sac

Transforming growth factor beta 1 (TGF beta 1) is shown here to be required for yolk sac haematopoiesis and endothelial differentiation. Mice with a targeted mutation in the TGF beta 1 gene were examined to determine the cause of prenatal lethality, which occurs in 50% of homozygous TGF beta 1 null (TGF beta 1-/-) conceptions. 50% of TGF beta 1-/- and 25% of TGF beta 1-+-) conceptions. 50% of TGF beta 1-/- and 25% of TGF beta 1+/- conceptuses were found to die at around 10.5 dpc. The primary defects were restricted to extraembryonic tissues, namely the yolk sac vasculature and haematopoietic system. The embryos per se showed developmental retardation, oedema and necrosis, which were probably secondary to the extraembryonic lesions. The defect in vasculogenesis appeared to affect endothelial differentiation, rather than the initial appearance and outgrowth of endothelial cells. Initial differentiation of yolk sac mesoderm to endothelial cells occurred, but defective differentiation resulted in inadequate capillary tube formation, and weak vessels with reduced cellular adhesiveness. Defective haematopoiesis resulted in a reduced erythroid cell number within the yolk sac. Defective yolk sac vasculogenesis and haematopoiesis were present either together, or in isolation of each other. The phenotypes are consistent with the observation of abundant TGF beta 1 gene expression in both endothelial and haematopoietic precursors. The data indicate that the primary effect of loss of TGF beta 1 function in vivo is not increased haematopoietic or endothelial cell proliferation, which might have been expected by deletion of a negative growth regulator, but defective haematopoiesis and endothelial differentiation.

Topics: Animals; Base Sequence; Blood Vessels; Cell Differentiation; Cells, Cultured; DNA Primers; Endothelium; Fetal Death; Hematopoiesis; In Situ Hybridization; Mice; Mice, Knockout; Molecular Sequence Data; Polymerase Chain Reaction; Transforming Growth Factor beta; Yolk Sac