Frizzled 4 regulates ventral blood vessel remodeling in the zebrafish retina.

BACKGROUND: Familial exudative vitreoretinopathy (FEVR) is a rare congenital disorder characterized by a lack of blood vessel growth to the periphery of the retina with secondary fibrovascular proliferation at the vascular-avascular junction. These structurally abnormal vessels cause leakage and hemorrhage, while the fibroproliferative scarring results in retinal dragging, detachment and blindness. Mutations in the FZD4 gene represent one of the most common causes of FEVR. METHODS: A loss of function mutation resulting from a 10-nucleotide insertion into exon 1 of the zebrafish fzd4 gene was generated using transcription activator-like effector nucleases (TALENs). Structural and functional integrity of the retinal vasculature was examined by fluorescent microscopy and optokinetic responses. RESULTS: Zebrafish retinal vasculature is asymmetrically distributed along the dorsoventral axis, with active vascular remodeling on the ventral surface of the retina throughout development. fzd4 mutants exhibit disorganized ventral retinal vasculature with discernable tubular fusion by week 8 of development. Furthermore, fzd4 mutants have impaired optokinetic responses requiring increased illumination. CONCLUSION: We have generated a visually impaired zebrafish FEVR model exhibiting abnormal retinal vasculature. These fish provide a tractable system for studying vascular biology in retinovascular disorders, and demonstrate the feasibility of using zebrafish for evaluating future FEVR genes identified in humans.

Neuropilin 1 (NRP1) hypomorphism combined with defective VEGF-A binding reveals novel roles for NRP1 in developmental and pathological angiogenesis.

Neuropilin 1 (NRP1) is a receptor for class 3 semaphorins and vascular endothelial growth factor (VEGF) A and is essential for cardiovascular development. Biochemical evidence supports a model for NRP1 function in which VEGF binding induces complex formation between NRP1 and VEGFR2 to enhance endothelial VEGF signalling. However, the relevance of VEGF binding to NRP1 for angiogenesis in vivo has not yet been examined. We therefore generated knock-in mice expressing Nrp1 with a mutation of tyrosine (Y) 297 in the VEGF binding pocket of the NRP1 b1 domain, as this residue was previously shown to be important for high affinity VEGF binding and NRP1-VEGFR2 complex formation. Unexpectedly, this targeting strategy also severely reduced NRP1 expression and therefore generated a NRP1 hypomorph. Despite the loss of VEGF binding and attenuated NRP1 expression, homozygous Nrp1(Y297A/Y297A) mice were born at normal Mendelian ratios, arguing against NRP1 functioning exclusively as a VEGF164 receptor in embryonic angiogenesis. By overcoming the mid-gestation lethality of full Nrp1-null mice, homozygous Nrp1(Y297A/Y297A) mice revealed essential roles for NRP1 in postnatal angiogenesis and arteriogenesis in the heart and retina, pathological neovascularisation of the retina and angiogenesis-dependent tumour growth.

PAGOD syndrome and vascular anomalies: is a defect embryonic angiogenesis? A case report and review.

PAGOD Syndrome is an acronym for lung and pulmonary arteries hypoplasia, agonadism, omphalocele / diaphragmatic defect and dextrocardia. A series of 21 patients is described, where 90.5% had a 46,XY karyotype and only two cases 46,XX; 66.6% exhibited a female phenotype and 28.6% ambiguous genitalia. The occurrence of two patients 46,XX excludes the Y chromosome as a carrier of the genetic defect and raises the possibility of a recessive X-linked inheritance, without ruling out that the observed cases in siblings may be due to mutations in other genes as Stra6, VEGFA, VEGFB, VEGFC, and alternative splicing of transcripts VEGFA, HIF1, HIF2, among others. Congenital malformations were observed in patients' genitals and gonads 85.7%, 66.6% in diaphragm and abdominal wall , heart 80.9%, 71.4% lungs, blood vessels 80.9% and 42.8% in abdomen. The review of patients has demonstrated a high degree of variability in the expression of malformations of organs and organ systems. Vascular malformations represent an important and characteristic component of PAGOD syndrome and whose base morphogenetic syndrome may be due to a defect in early embryonic angiogenesis with impact on organogenesis and system development. Among genes related to vascular remodeling during embryogenesis, tissue regeneration and carcinogenesis, the Endothelial Growth Factor D Vascular (VEGFD), located in the Xp22.31 region, with expression in lung, heart, small intestine, uterus, breast, neuroblastoma and neural tissue, represents a strong candidate for molecular analysis as a cause of the syndrome.

More than nervous: the emerging roles of plexins.

Plexins are the receptors for semaphorins, a large family of axon guidance cues. Accordingly, the role of plexins in the development of the nervous system was the first to be acknowledged. However, the expression of plexins is not restricted to neuronal cells, and recent research has been increasingly focused on the roles of plexin-semaphorin signalling outside of the nervous system. During embryogenesis, plexins regulate the development of many organs, including the cardiovascular system, skeleton and kidney. They have also been shown to be involved in immune system functions and tumour progression. Analyses of the plexin signalling in different tissues and cell types have provided new insight to the versatility of plexin interactions with semaphorins and other cell-surface receptors. In this review we try to summarise the current understanding of the roles of plexins in non-neural development and immunity.

Alteration of developmental and pathological retinal angiogenesis in angptl4-deficient mice.

Proper vessel maturation, remodeling of endothelial junctions, and recruitment of perivascular cells is crucial for establishing and maintaining vessel functions. In proliferative retinopathies, hypoxia-induced angiogenesis is associated with disruption of the vascular barrier, edema, and vision loss. Therefore, identifying factors that regulate vascular maturation is critical to target pathological angiogenesis. Given the conflicting role of angiopoietin-like-4 (ANGPTL4) reported in the current literature using gain of function systems both in vitro and in vivo, the goal of this study was to characterize angiogenesis, focusing on perinatal retinal vascularization and pathological circumstances in angpl4-deficient mice. We report altered organization of endothelial junctions and pericyte coverage, both leading to impaired angiogenesis and increased vascular leakage that were eventually caught up, suggesting a delay in vessel maturation. In a model of oxygen-induced retinopathy, pathological neovascularization, which results from tissue hypoxia, was also strongly inhibited in angptl4-deficient mice. This study therefore shows that ANGPTL4 tunes endothelial cell junction organization and pericyte coverage and controls vascular permeability and angiogenesis, both during development and in pathological conditions.

Retina-specific activation of a sustained hypoxia-like response leads to severe retinal degeneration and loss of vision.

Loss of vision and blindness in human patients is often caused by the degeneration of neuronal cells in the retina. In mouse models, photoreceptors can be protected from death by hypoxic preconditioning. Preconditioning in low oxygen stabilizes and activates hypoxia inducible transcription factors (HIFs), which play a major role in the hypoxic response of tissues including the retina. We show that a tissue-specific knockdown of von Hippel-Lindau protein (VHL) activated HIF transcription factors in normoxic conditions in the retina. Sustained activation of HIF1 and HIF2 was accompanied by persisting embryonic vasculatures in the posterior eye and the iris. Embryonic vessels persisted into adulthood and led to a severely abnormal mature vessel system with vessels penetrating the photoreceptor layer in adult mice. The sustained hypoxia-like response also activated the leukemia inhibitory factor (LIF)-controlled endogenous molecular cell survival pathway. However, this was not sufficient to protect the retina against massive cell death in all retinal layers of adult mice. Caspases 1, 3 and 8 were upregulated during the degeneration as were several VHL target genes connected to the extracellular matrix. Misregulation of these genes may influence retinal structure and may therefore facilitate growth of vessels into the photoreceptor layer. Thus, an early and sustained activation of a hypoxia-like response in retinal cells leads to abnormal vasculature and severe retinal degeneration in the adult mouse retina.

Zebrafish mutants provide insights into Apolipoprotein B functions during embryonic development and pathological conditions.

Apolipoprotein B (ApoB) is the primary protein of chylomicrons, VLDLs, and LDLs and is essential for their production. Defects in ApoB synthesis and secretion result in several human diseases, including abetalipoproteinemia and familial hypobetalipoproteinemia (FHBL1). In addition, ApoB-related dyslipidemia is linked to nonalcoholic fatty liver disease (NAFLD), a silent pandemic affecting billions globally. Due to the crucial role of APOB in supplying nutrients to the developing embryo, ApoB deletion in mammals is embryonic lethal. Thus, a clear understanding of the roles of this protein during development is lacking. Here, we established zebrafish mutants for 2 apoB genes: apoBa and apoBb.1. Double-mutant embryos displayed hepatic steatosis, a common hallmark of FHBL1 and NAFLD, as well as abnormal liver laterality, decreased numbers of goblet cells in the gut, and impaired angiogenesis. We further used these mutants to identify the domains within ApoB responsible for its functions. By assessing the ability of different truncated forms of human APOB to rescue the mutant phenotypes, we demonstrate the benefits of this model for prospective therapeutic screens. Overall, these zebrafish models uncover what are likely previously undescribed functions of ApoB in organ development and morphogenesis and shed light on the mechanisms underlying hypolipidemia-related diseases.

Tie2Cre-mediated inactivation of plexinD1 results in congenital heart, vascular and skeletal defects.

PlexinD1 is a membrane-bound receptor that mediates signals derived from class 3 secreted semaphorins. Although semaphorin signaling in axon guidance in the nervous system has been extensively studied, functions outside the nervous system including important roles in vascular patterning have also been demonstrated. Inactivation of plexinD1 leads to neo-natal lethality, structural defects of the cardiac outflow tract, peripheral vascular abnormalities, and axial skeletal morphogenesis defects. PlexinD1 is expressed by vascular endothelial cells, but additional domains of expression have also been demonstrated including in lymphocytes, osteoblasts, neural crest and the central nervous system. Hence, the cell-type specific functions of plexinD1 have remained unclear. Here, we describe the results of tissue-specific gene inactivation of plexinD1 in Tie2 expressing precursors, which recapitulates the null phenotype with respect to congenital heart, vascular, and skeletal abnormalities resulting in neonatal lethality. Interestingly, these mutants also have myocardial defects not previously reported. In addition, we demonstrate functions for plexinD1 in post-natal retinal vasculogenesis and adult angiogenesis through the use of inducible cre-mediated deletion. These results demonstrate an important role for PlexinD1 in embryonic and adult vasculature.

Identification and expression analysis of zebrafish testis-specific gene 10 (tsga10).

Several clinical studies suggest that testis-specific gene antigen 10 (TSGA10) is a cancer-testis antigen with a discernible expression pattern in the testis. Recent studies have highlighted that TSGA10 overexpression in HeLa cells impairs the transcriptional activity of hypoxia-inducible factor alpha (HIF-1α) and inhibits angiogenesis. In this study, we used the zebrafish as a powerful model organism to identify and characterize the orthologue of TSGA10. We analyzed the gene expression pattern by RT-PCR and whole mount in situ hybridization and overexpressed the tsga10 protein by mRNA microinjection. Our results revealed that during early development, tsga10 expression is enriched, but gradually subsides between 0 and 72 hours post fertilization (hpf). There was no detectable transcript at the larval stages. In adult fish, we found high expression levels of tsga10 in the testis and unfertilized egg and low levels of gene expression in the brain, eyes and muscle. Overexpression of tsga10, using tsga10 mRNA microinjection into one-cell stage embryos, resulted in angiogenic and morphological defects at 24 and 48 hpf. This study clarified the expression pattern of tsga10 in different developmental stages and adult tissues, suggesting that tsga10 may have a related biological role in different cell types and tissues. Our results indicate that tsga10 mRNA at embryonic stages is maternally deposited, indicating a transient functional role during embryogenesis. Our findings suggest that tsga10 is a human orthologous gene relevant for future studies to elucidate its mechanism of action in angiogenesis.

Development of the hyaloid, choroidal and retinal vasculatures in the fetal human eye.

The development of the ocular vasculatures is perfectly synchronized to provide the nutritional and oxygen requirements of the forming human eye. The fetal vasculature of vitreous, which includes the hyaloid vasculature, vasa hyaloidea propria, and tunica vasculosa lentis, initially develops around 4-6 weeks gestation (WG) by hemo-vasculogenesis (development of blood and blood vessels from a common progenitor, the hemangioblast). This transient fetal vasculature expands around 12 WG by angiogenesis (budding from primordial vessels) and remains until a retinal vasculature begins to form. The fetal vasculature then regresses by apoptosis with the assistance of macrophages/hyalocytes. The human choroidal vasculature also forms by a similar process and will supply nutrients and oxygen to outer retina. This lobular vasculature develops in a dense collagenous tissue juxtaposed with a cell constitutively producing vascular endothelial growth factor (VEGF), the retinal pigment epithelium. This epithelial/endothelial relationship is critical in maintaining the function of this vasculature throughout life and maintaining it's fenestrated state. The lobular capillary system (choriocapillaris) develops first by hemo-vasculogenesis and then the intermediate choroidal blood vessels form by angiogenesis, budding from the choriocapillaris. The human retinal vasculature is the last to develop. It develops by vasculogenesis, assembly of CXCR4+/CD39+ angioblasts or vascular progenitors perhaps using Muller cell Notch1 or axonal neuropilinin-1 for guidance of semaphorin 3A-expressing angioblasts. The fovea never develops a retinal vasculature, which is probably due to the foveal avascular zone area of retina expressing high levels of antiangiogenic factors. From these studies, it is apparent that development of the mouse ocular vasculatures is not representative of the development of the human fetal, choroidal and retinal vasculatures.

Genetic interaction between Lef1 and Alx4 is required for early embryonic development.

Lymphoid Enhancer Factor-1 (Lef1) facilitates the assembly of transcriptional regulatory complexes and mediates nuclear responses to Wnt signals. We determined previously that the mesenchymally restricted, paired-like homeodomain protein Aristaless-like 4 (Alx4) interacts with Lef1 and together alters promoter activity of candidate genes. In order to define their overlapping functions, mice deficient for both Lef1 and Alx4 activity (Lef1-/-/Alx4lstD/lstD) were produced. Whereas embryos lacking either Lef1 or Alx4 activity remain viable up to or after birth, early embryonic lethality results when both factors were absent. No viable Lef1-/-/Alx4lstD/lstD embryos were recovered beyond 9.5 dpc. Between E8.5 and E10, viable Lef1-/-/Alx4lstD/lstD embryos were developmentally delayed 0.5 days relative to littermates of all other genotypes. Principle among the alterations seen in Lef1-/-/Alx4lstD/lstD animals was defective vasculature in both embryonic and extra-embryonic tissues. In the yolk sac, while the vascular network is present, it were greatly diminished and large vitelline vessels were largely absent. Platelet/endothelial cell adhesion molecule (PECAM) staining revealed that the major vessels in the head of compound mutant embryos were absent, while the other vessels were finer than those seen in normal littermates. Pools of blood and pericardial effusion were also apparent in Lef1-/-/Alx4lstD/lstD animals, further indicative of a defective vasculature. These data confirm genetically the interaction between Lef1 and Alx4 and further reveal unknown, overlapping roles for these transcription factors in embryonic vasculogenesis.

PLGF, a placental marker of fetal brain defects after in utero alcohol exposure.

Most children with in utero alcohol exposure do not exhibit all features of fetal alcohol syndrome (FAS), and a challenge for clinicians is to make an early diagnosis of fetal alcohol spectrum disorders (FASD) to avoid lost opportunities for care. In brain, correct neurodevelopment requires proper angiogenesis. Since alcohol alters brain angiogenesis and the placenta is a major source of angiogenic factors, we hypothesized that it is involved in alcohol-induced brain vascular defects. In mouse, using in vivo repression and overexpression of PLGF, we investigated the contribution of placenta on fetal brain angiogenesis. In human, we performed a comparative molecular and morphological analysis of brain/placenta angiogenesis in alcohol-exposed fetuses. Results showed that prenatal alcohol exposure impairs placental angiogenesis, reduces PLGF levels and consequently alters fetal brain vasculature. Placental repression of PLGF altered brain VEGF-R1 expression and mimicked alcohol-induced vascular defects in the cortex. Over-expression of placental PGF rescued alcohol effects on fetal brain vessels. In human, alcohol exposure disrupted both placental and brain angiogenesis. PLGF expression was strongly decreased and angiogenesis defects observed in the fetal brain markedly correlated with placental vascular impairments. Placental PGF disruption impairs brain angiogenesis and likely predicts brain disabilities after in utero alcohol exposure. PLGF assay at birth could contribute to the early diagnosis of FASD.

The chick embryo chorioallantoic membrane as a model system for the study of tumor angiogenesis, invasion and development of anti-angiogenic agents.

Angiogenesis, the formation of new blood vessels, is essential for tumor growth, progression and metastasis. The development of agents that target tumor vasculature is ultimately dependent on the availability of appropriate preclinical screening assays. The chorioallantoic membrane (CAM) assay is well established and widely used as a model to examine angiogenesis, and anti-angiogenesis. This review 1) summarizes the currently used angiogenesis assays and the importance of CAM model among them; 2) summarizes the current knowledge about the development and structure of the CAM's capillary bed; 3) reports findings regarding the role played by molecular signaling pathways in angiogenesis process; 4) discusses the use, advantages and limitations of the CAM as a model for studying tumor angiogenesis and invasiveness, as well as development of angiogenic and/or anti-angiogenic agents; 5) discusses the importance of standardization of the major methodologies for all aspects of the use of the CAM in angiogenesis-related studies; 6) and finally, summarizes major findings regarding the agents developed by the use of CAM model in the study of tumor angiogenesis, invasion and development of anti-angiogenic agents.

The mouse tie receptor tyrosine kinase gene: expression during embryonic angiogenesis.

Angiogenesis, the process by which new blood vessels are formed, is essential in reproduction, development, wound repair and oncogenesis. Endothelial receptor tyrosine kinases are likely to play key roles in the intercellular signalling controlling angiogenesis. We have here analysed the expression of the endothelial receptor tyrosine kinase tie during the earliest stages of vascular development. The mouse tie cDNA was isolated and sequenced and the exon structure of the coding region was determined. The part of the tie gene encoding the extracellular domain was found to be organized in exons specifying the characteristic domains of the Tie polypeptide. Early postimplantation mouse tissues were analysed for tie expression by in situ hybridization. No tie mRNA was detected in 7.5 day mouse embryos. In 8.5 day embryos, tie expression was observed in differentiating angioblasts of the head mesenchyme, in the splanchnopleure and dorsal aorta as well as in migrating endothelial cells of the developing heart. A weak tie signal was also obtained from angioblasts in the blood islands of the yolk sac. Furthermore, tie mRNA was prominent in the endocardium of the embryo and in the endothelial cells forming the lung vasculature. Expression of tie persisted in the lung capillaries of adult mice, but was decreased in the endocardium. These results suggest that the tie receptor tyrosine kinase is involved in angiogenesis and/or maintenance of endothelial cell functions.

Effects of hyperthyroidism on expression of vascular endothelial growth factor (VEGF) and apoptosis in fetal adrenal glands.

This study investigated the expression of vascular endothelial growth factor (VEGF), vascular density, and apoptosis in fetal rat adrenal glands with hyperthyroidism in late gestation. Twelve mature female Wistar albino rats with the same biological and physiological features were used for this study. Rats were divided into two groups: control and hyperthyroidism. Hyperthyroidism was induced by daily subcutaneous injections of L-thyroxine (250 µg/kg) before pregnancy for 21 days and during pregnancy. Rats in the control and hyperthyroidism groups were caged according to the number of male rats. Zero day of pregnancy (Day 0) was indicated when the animals were observed to have microscopic sperm in vaginal smears. Pregnant rats were sacrificed on the 20th day of pregnancy; blood from each animal was collected to determine the concentrations of maternal adrenocorticotropic hormone and thyroxine. Rat fetuses were then quickly removed from the uterus, and the adrenal glands of the fetuses were dissected. VEGF expression, vascular density, and apoptosis were analyzed in fetal rat adrenal glands. Maternal serum levels of the adrenocorticotropic hormone and free thyroxine were significantly higher in the hyperthyroidism group than in the control group. Immunohistochemistry revealed that the number of VEGF positive cells and vessel density significantly increased in the hyperthyroidism rat fetal adrenal group compared with the control group. Hyperthyroidism did not change the fetal and placental weights and the number of fetuses. This study demonstrates that hyperthyroidism may have an effect on the development of rat adrenal glands mediated by VEGF expression, angiogenesis, and apoptosis.

[Genetic factors related to intracranial arteriovenous malformations]. / Les facteurs génétiques associés aux malformations artério-veineuses cérébrales.

Genetic studies are interesting not only in the diagnosis and screening of new cases within a family harboring a particular disease, but also in understanding the underlying genetic and molecular factors related to that disease. Such studies revealed 3 categories of cerebral arteriovenous malformations in relationship to possible genetic factors. The first one concerns cerebral arteriovenous malformations in relationship to inherited diseases where a genetic support is clearly identified. Hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber disease) represents the most classical picture. The second category corresponds to familial cases of cerebral arteriovenous malformations were several members and relatives of the same family harboring the pathology without clear demonstration of any genetic basis. The third category includes cerebral arteriovenous malformations described in association with neurocutaneous disorders issued from maldevelopment events. Sturge-Weber disease and Wyburn-Mason syndrome best illustrate this category. A review of these categories will help in a better understanding of some genetic issues related to cerebral arteriovenous malformations.

Valproic acid substantially downregulated genes folr1, IGF2R, RGS2, COL6A3, EDNRB, KLF6, and pax-3, N-acetylcysteine alleviated most of the induced gene alterations in chicken embryo model.

Valproic acid induced teratogenicity at genetic and somatic levels, the action mechanism is still unclear. We hypothesized that folate receptor gene (folr1) and others may be interacting to elicit neural tube defect (NTD), while N-acetylcysteine (NAC) may be beneficial for protection. In chicken embryo model, the experiment was conducted in two parts. The first part was carried out to test the optimum dose of VPA. The second part was conducted to test the protective effect of NAC at doses 10 and 20 mM. VPA induced dysvascularization, incomplete somite enclosure, histone deacetylase (HDAC) inhibition, folate deficiency, homocysteine accumulation, SOD inhibition, glutathione depletion, elevated MDA and hydrogen peroxide. NAC alleviated most of these adverse effects. The microarray analysis revealed 17 genes downregulated and four upregulated. The relevancy covered translation (23%), signal transduction (23%), transcription (16%), cell adhesion (16%), neural cell migration (8%), transport (7%), and organismal development (7%). The genes insulin-like growth factor 2 receptor gene (IGF2R), regulator of G-protein signaling 4 gene (RGS4), alpha 3 (VI) collagen gene (COL6A3), endothelin receptor type b gene (EDNRB), and Krüppel-like factor 6 gene (KLF6) substantially downregulated in reality were directly intermodulating and associated with NTD. VPA downregulated folr1 gene in a dose responsive manner without affecting pax-3 gene, which was ascribed to the metahypoxic state. Conclusively, VPA affects 21 genes: 17 downregulated and four upregulated. VPA dose responsively downregulates gene folr1 without affecting pax-3 gene. These adverse effects can be partially alleviated by N-acetylcysteine.

Síndrome PAGOD y anomalías vasculares: ¿es un defecto de la angiogénesis embrionaria? Un nuevo caso y revisión / PAGOD syndrome and vascular anomalies: is a defect embryonic angiogenesis? A case report and review

El Síndrome PAGOD es un acrónimo de hipoplasia de pulmón y arterias pulmonares, agonadismo, onfalocele / defecto diafragmático y dextrocardia. Se describe una serie de 21 pacientes, en la cual, 90,5 % presentó un cariotipo 46,XY y solo dos casos 46,XX; el 66,6 % exhibió un fenotipo femenino y 28,6 % genitales ambiguos. La ocurrencia de dos paciente 46,XX excluye al cromosoma Y como portador del defecto genético y plantea la posibilidad de una herencia recesiva ligada al cromosoma X, sin descartar que los casos observados en hermanos puedan deberse a mutaciones en otros genes como STRA6, VEGFA, VEGFB, VEGFC, transcritos de empalmes alternativos de VEGFA, HIF1, HIF2, entre otros. Las malformaciones congénitas observadas en los pacientes fueron: genitales y gónadas 85,7 %, diafragma y pared 66,6 %, cardíaco 80,9 %, pulmonar 71,4 %, vascular 80,9 % y abdomen 42,8 %. La revisión de los pacientes ha demostrado un alto grado de variabilidad en la expresividad de malformaciones de órganos, aparatos o sistemas. Las malformaciones vasculares representan un componente importante y característico del síndrome PAGOD y cuya base morfogenética del síndrome pueda deberse a un defecto de la angiogénesis embrionaria temprana con repercusión en la organogénesis de aparatos y sistemas. Dentro de los genes relacionados con el remodelamiento vascular durante la embriogénesis, regeneración tisular y carcinogénesis está el Factor de Crecimiento del Endotelio Vascular D (VEGFD), localizado en Xp22.31, con expresión en pulmón, corazón, intestino delgado, pulmón fetal, útero, mamas, tejido neural y neuroblastoma, el cual representa un fuerte candidato para su análisis molecular como una de las posibles causa del síndrome.

PAGOD Syndrome is an acronym for lung and pulmonary arteries hypoplasia, agonadism, omphalocele / diaphragmatic defect and dextrocardia. A series of 21 patients is described, where 90.5% had a 46,XY karyotype and only two cases 46,XX; 66.6% exhibited a female phenotype and 28.6% ambiguous genitalia. The occurrence of two patients 46,XX excludes the Y chromosome as a carrier of the genetic defect and raises the possibility of a recessive X-linked inheritance, without ruling out that the observed cases in siblings may be due to mutations in other genes as Stra6, VEGFA, VEGFB, VEGFC, and alternative splicing of transcripts VEGFA, HIF1, HIF2, among others. Congenital malformations were observed in patients’ genitals and gonads 85.7%, 66.6% in diaphragm and abdominal wall , heart 80.9%, 71.4% lungs, blood vessels 80.9% and 42.8% in abdomen. The review of patients has demonstrated a high degree of variability in the expression of malformations of organs and organ systems. Vascular malformations represent an important and characteristic component of PAGOD syndrome and whose base morphogenetic syndrome may be due to a defect in early embryonic angiogenesis with impact on organogenesis and system development. Among genes related to vascular remodeling during embryogenesis, tissue regeneration and carcinogenesis, the Endothelial Growth Factor D Vascular (VEGFD), located in the Xp22.31 region, with expression in lung, heart, small intestine, uterus, breast, neuroblastoma and neural tissue, represents a strong candidate for molecular analysis as a cause of the syndrome.

Angiopoietin-1 is essential in mouse vasculature during development and in response to injury.

Angiopoietin-1/Tek signaling is a critical regulator of blood vessel development, with conventional knockout of angiopoietin-1 or Tek in mice being embryonically lethal due to vascular defects. In addition, angiopoietin-1 is thought to be required for the stability of mature vessels. Using a Cre-Lox conditional gene targeting approach, we have studied the role of angiopoietin-1 in embryonic and adult vasculature. We report here that angiopoietin-1 is critical for regulating both the number and diameter of developing vessels but is not required for pericyte recruitment. Cardiac-specific knockout of angiopoietin-1 reproduced the phenotype of the conventional knockout, demonstrating that the early vascular abnormalities arise from flow-dependent defects. Strikingly, deletion in the entire embryo after day E13.5 produced no immediate vascular phenotype. However, when combined with injury or microvascular stress, angiopoietin-1 deficiency resulted in profound organ damage, accelerated angiogenesis, and fibrosis. These findings redefine our understanding of the biological roles of angiopoietin-1: it is dispensable in quiescent vessels but has a powerful ability to modulate the vascular response after injury.

The yin, the yang, and the angiopoietin-1.

Twenty years after the discovery of the vascular endothelial Tie receptor tyrosine kinases and 15 years after the discovery of the Tie2 ligand, angiopoietin-1 (Angpt1, also known as Ang1), a study published in the current issue of the JCI reveals an unexpected loss-of-function phenotype of mice conditionally deleted of the Angpt1 gene. The results suggest that Angpt1 is needed as a vascular stabilizing factor that organizes and limits the angiogenesis response and protects from pathological consequences, such as tissue fibrosis.