The Ubiquitin E3 Ligase NOSIP Modulates Protein Phosphatase 2A Activity in Craniofacial Development

Holoprosencephaly is a common developmental disorder in humans characterised by incomplete brain hemisphere separation and midface anomalies. The etiology of holoprosencephaly is heterogeneous with environmental and genetic causes, but for a majority of holoprosencephaly cases the genes associated with the pathogenesis could not be identified so far. Here we report the generation of knockout mice for the ubiquitin E3 ligase NOSIP. The loss of NOSIP in mice causes holoprosencephaly and facial anomalies including cleft lip/palate, cyclopia and facial midline clefting. By a mass spectrometry based protein interaction screen we identified NOSIP as a novel interaction partner of protein phosphatase PP2A. NOSIP mediates the monoubiquitination of the PP2A catalytic subunit and the loss of NOSIP results in an increase in PP2A activity in craniofacial tissue in NOSIP knockout mice. We conclude, that NOSIP is a critical modulator of brain and craniofacial development in mice and a candidate gene for holoprosencephaly in humans.     

Holoprosencephaly in a fetal macaque (Macaca nemestrina) following weekly exposure to ethanol

Previous studies in rodents have indicated that the facial changes of fetal alcohol syndrome (FAS) closely resemble those of a mild form of holoprosencephaly. In order to examine this relationship in non-human primates, we evaluated a 133-day gestation macaque (Macaca nemestrina) with holoprosencephaly, median cleft lip and palate, and encephalocele. The mother had been given ethanol once per week (1.8 g/kg body weight) from weeks 2 to 19 postconception. Diagnosis of holoprosencephaly was made following ultrasound evaluation for polyhydramnios and delivery of the female fetus by caesarean section. Another fetus of identical age was delivered by caesarean section for use as a control. Both fetuses were studied by anthropometric, gross, radiographic, and histologic techniques. In the fetus exposed to alcohol, no extracranial anomalies were identified and the karyotype was normal. The brain was micrencephalic, with absent olfactory bulbs, tracts, optic nerves and chiasma, fused frontal lobes, and a single, dilated lateral ventricle; a parietooccipital encephalocele consisted of thin, dysplastic cortex bordering the ventricle; the cerebellum was dysplastic and superiorly displaced. Within the craniofacial complex, anophthalmia was bilateral; premaxillary components were absent, palatal shelves separate, the maxillae closeset, and the ethmoid bone small and deformed. Most of these defects are similar to those encountered in humans with holoprosencephaly and support the hypothesis of shared etiologic and pathogenetic relations between the facial anomalies of fetal alcohol syndrome and holoprosencephaly.     

Midline and laterality defects: left and right meet in the middle

The aim of this review is to summarize some of the recent advances in molecular embryology that help to explain the pathogenesis of holoprosencephaly (HPE), or its related malformation in model organisms, cyclopia, and laterality defects in humans, derived from detailed analysis of similar malformations in animal models. Recently, defects in several developmental pathways including those operated by the Sonic hedgehog and Nodal signaling factors have been implicated as causes of HPE or laterality defects in humans. Here we summarize the findings in animal models that indicate that both defects can be explained by mechanisms that relate to the proper development of the axial midline in vertebrates. Published 2001 John Wiley & Sons, Inc.     

Unique Alterations of an Ultraconserved Non-Coding Element in the 3'UTR of ZIC2 in Holoprosencephaly

Coding region alterations of ZIC2 are the second most common type of mutation in holoprosencephaly (HPE). Here we use several complementary bioinformatic approaches to identify ultraconserved cis-regulatory sequences potentially driving the expression of human ZIC2. We demonstrate that an 804 bp element in the 3' untranslated region (3'UTR) is highly conserved across the evolutionary history of vertebrates from fish to humans. Furthermore, we show that while genetic variation of this element is unexpectedly common among holoprosencephaly subjects (6/528 or >1%), it is not present in control individuals. Two of six proband-unique variants are de novo, supporting their pathogenic involvement in HPE outcomes. These findings support a general recommendation that the identification and analysis of key ultraconserved elements should be incorporated into the genetic risk assessment of holoprosencephaly cases.     

Microcephaly in familial holoprosencephaly

The holoprosencephaly sequence (HS) is characterized by abnormalities in forebrain cleavage and midface development. Familial holoprosencephaly has been reported in several families and there appears to be variable expression of the disorder in those who inherit the gene. Previous investigators have suggested hypotelorism and/or missing central incisors as mild manifestations of autosomal dominant HS. We evaluated a large kindred with three individuals with severe brain anomalies and 12 individuals with minor manifestations of the disorder. The most consistent sign in those mildly affected was microcephaly. We suggest that head circumference is an important part of the evaluation of the relatives of a patient with holoprosencephaly.     

Disorders of post-squalene cholesterol biosynthesis leading to human dysmorphogenesis.

Insights in molecular developmental biology in animals and humans are facilitating the understanding of pathophysiologic mechanisms in dysmorphogenesis or abnormalities in normal embryologic structural development. A milestone was recognition of the role of shh in morphogenesis of craniofacial structures, especially the development of holoprosencephaly. The dependence of hedgehog morphogens on cholesterol modification for normal hedgehog signaling function has particular relevance to disorders of cholesterol synthesis which manifest dysmorphogenesis. Four human disorders of morphogenesis (Smith-Lemli-Opitz syndrome, desmosterolosis, X-linked chondrodysplasia punctata, CHILD syndrome) have recently been shown to be caused by sterol abnormalities resulting from cholesterol biosynthesis enzyme deficiencies. This review summarizes the clinical, biochemical and molecular data in these disorders with an emphasis on understanding the pathophysiology of dysmorphogenesis.     

Inductive patterning of the embryonic brain in Drosophila

In vertebrates (deuterostomes), brain patterning depends on signals from adjacent tissues. For example, holoprosencephaly, the most common brain anomaly in humans, results from defects in signaling between the embryonic prechordal plate (consisting of the dorsal foregut endoderm and mesoderm) and the brain. I have examined whether a similar mechanism of brain development occurs in the protostome Drosophila, and find that the foregut and mesoderm act to pattern the fly embryonic brain. When the foregut and mesoderm of Drosophila are ablated, brain patterning is disrupted. The loss of Hedgehog expressed in the foregut appears to mediate this effect, as it does in vertebrates. One mechanism whereby these defects occur is a disruption of normal apoptosis in the brain. These data argue that the last common ancestor of protostomes and deuterostomes had a prototype of the brains present in modern animals, and also suggest that the foregut and mesoderm contributed to the patterning of this 'proto-brain'. They also argue that the foreguts of protostomes and deuterostomes, which have traditionally been assigned to different germ layers, are actually homologous.     

二维及实时三维超声对胎儿全前脑畸形的诊断价值探讨

目的：探讨二维及实时三维超声联合诊断胎儿全前脑畸形的价值。方法：二维超声系统检查发现胎儿颅脑结构异常者进行胎儿颅脑和颜面部实时三维成像,并将超声诊断结果与引产后尸检结果进行对照分析。结果：在20918例孕16~41周的胎儿中,经引产后尸检证实的全前脑畸形5例,其中无叶全前脑3例,半叶全前脑2例,均与产前超声检查结果相符合,二维联合实时三维超声检查对胎儿全前脑畸形诊断符合率为100%。结论：二维超声联合实时三维超声检查是诊断胎儿全前脑畸形可靠有效的方法,两者联合应用可提高产前全前脑的诊断率。     

Cdon and Boc: Two transmembrane proteins implicated in cell-cell communication

Cdon and Boc, and their Drosophila homologues Ihog and Boi, are evolutionary conserved transmembrane glycoproteins belonging to a subgroup of the Immunoglobulin superfamily of cell adhesion molecules (CAMs). Initially isolated in vertebrates as CAMs that link cadherin function with MAPK signaling in myoblast differentiation, they have thereafter been shown to act as essential receptors for the Hedgehog (Hh) family of secreted proteins. They associate with both ligand and other Hh receptor components, including Ptch and Gas1, thus forming homo- and heteromeric complexes. In Drosophila, they are also involved in ligand processing and release from Hh producing cells. Cdon/Boc and Ihog/Boi can substitute one another and play redundant functions is some contexts. In addition, Boc, but not Cdon, mediates axon guidance information provided by Hh in specific neuronal populations, whereas mutations in the CDON cause holoprosencephaly, a human congenital anomaly defined by forebrain midline defects prominently associated with diminished Hh pathway activity.     

Diversity of the killer cell Ig-like receptors of rhesus monkeys

Because the killer cell Ig-like receptors (KIRs) have only been characterized in humans and chimpanzees, we do not have a full understanding of their evolutionary history. Therefore, cDNAs encoding the KIR molecules of five rhesus monkeys were characterized, and were found to differ from the KIR molecules identified in humans and chimpanzees. Whereas only one KIR2DL4 molecule is detected in humans and chimpanzees, two distinct KIR2DL4 homologues were identified in the monkeys. Although the two human KIR3DL molecules are limited in their polymorphism, the KIR3DL homologues in the monkeys were highly polymorphic. Up to five KIR3DL homologues were identified in each monkey that was studied, and eleven distinct KIR3DL molecules were detected in the five rhesus monkeys. Two novel families of KIR molecules were identified in the rhesus monkeys, KIR3DH and KIR1D. The KIR3DH molecules have three Ig domains, transmembrane domains homologous to KIR2DL4 molecules that contain an arginine, and short cytoplasmic domains. With these features, the KIR3DH molecules resemble the activating forms of the human KIR molecules. The KIR1D molecule encodes only one complete Ig domain before a frame-shift in the second Ig domain occurs, leading to early termination of the molecule. Multiple splice variants of KIR1D exist that encode at least one Ig domain, as well as transmembrane and cytoplasmic domains. The extensive diversity of the rhesus monkey KIR3DL homologues and the novel KIR3DH and KIR1D molecules suggests that the KIR family of molecules has evolved rapidly during the evolution of primates.     

THERPA: A small molecule database related to prion protein regulation and prion diseases progression

Prion diseases are fatal neurodegenerative disorders that affect humans and animals. Although various small molecules have been evaluated for application in the treatment of prion diseases, none have been shown to be efficacious. Expanding our knowledge of these molecules is important for understanding of the complex mechanisms of prion diseases. To improve access to the scattered information on small molecules related to prion diseases, we built a database of therapeutic molecules associated with prion diseases (THERPA, therpa.pythonanywhere.com). THERPA includes 119 small molecules and their 283 relationships with prion diseases. THERPA is an interactive visual database and useful for improving search efficiency which can help researchers identify intrinsic small molecules that can be used for developing therapeutics for prion diseases.     

Overview: from the horse experimentation by Prof. Akira Fujinami to paramyosin

Professor Akira Fujinami demonstrated for the first time in the world that acquired immunity might be induced against macroparasites such as schistosomes. Since then, vaccination models have been developed using various species of animals, among which the attenuated vaccine model in the mouse has been utilized mostly to clarify immune effector mechanisms and define candidate vaccine molecules. However, further studies are necessary on immune responses to defined parasite molecules in humans, because some discrepancies in immune responses still exist between animals and humans, and apparently genetic influence should be taken into consideration in such studies on defined molecules. Despite of some limitations, vaccine trials in livestock against Schistosoma japonicum may provide useful information for development of vaccines against the other human infections caused by S. mansoni or S. haematobium. In this overview, studies carried out mainly by Japanese investigators towards vaccine development will be described.     

Development of calorie restriction mimetics as therapeutics for obesity, diabetes, inflammatory and neurodegenerative diseases

Calorie restriction (CR) is the most robust intervention that decreases morbidity and mortality, and thereby increases the lifespan of many organisms. Although the signaling pathways involved in the beneficial effects of CR are not yet fully understood. Several candidate pathways and key molecules have been identified. The effects of CR are highly conserved from lower organisms such as yeast to higher mammals such as rodents and monkeys. Recent studies have also demonstrated beneficial effects of CR in humans, although we need much longer studies to evaluate whether CR also increases the lifespan of humans. In reality, it is difficult for us to conduct CR interventions in humans because the subjects must be kept in a state of hunger and the duration of this state needed to achieve a clinically meaningful effect is still unknown. Thus, research in this field is focusing on the development of molecules that mimic the beneficial effects of CR without reducing food intake. Some of these candidate molecules include plant-derived functional chemicals (phyto-chemicals), synthetic small molecules, and endocrine molecules such as adipokines. Several studies have already shown that this research field may yield novel drugs for the treatment of age-related diseases such as diabetes. In this article, we describe the target pathways, candidate molecules, and strategies to develop CR mimetics.     

Agnathia malformation complex associated with a cystic distention of the oral cavity and hydranencepahly

A fetus with a severe variant of the agnathia malformation complex (AMC) was delivered following prenatal diagnostic evaluation with ultrasonography. The constellation of anomalies that accompanied the agnathia included holoprosencephaly, hydranencephaly, situs inversus, and polysplenia. Recently, several authors have reported the association between the agnathia, holoprosencephaly, and situs inversus. We present evidence which suggests that, when hydranencephaly is also present, this may represent the most severe variant of the AMC. Our case is presented, the literature is reviewed, and a hypothesis regarding the embryopathologic mechanism is discussed.     

Protein-protein interactions, cytoskeletal regulation and neuronal migration

Neuronal migration, like the migration of many cell types, requires an extensive rearrangement of cell shape, mediated by changes in the cytoskeleton. The genetic analysis of human brain malformations has identified several biochemical players in this process, including doublecortin (DCX) and LIS1, mutations of which cause a profound migratory disturbance known as lissencephaly ('smooth brain') in humans. Studies in mice have identified additional molecules such as Cdk5, P35, Reelin, Disabled and members of the LDL superfamily of receptors. Understanding the cell biology of these molecules has been a challenge, and it is not known whether they function in related biochemical pathways or in very distinct processes. The last year has seen rapid advances in the biochemical analysis of several such molecules. This analysis has revealed roles for some of these molecules in cytoskeletal regulation and has shown an unexpected conservation of the genetic pathways that regulate neuronal migration in humans and nuclear movement in simple eukaryotic organisms.     

A case of methotrexate embryopathy with holoprosencephaly, expanding the phenotype

BACKGROUND: Methotrexate (MTX) embryopathy was described nearly 50 years ago, when this agent began to be used as a cancer treatment and abortifacient. In this report we describe a case with typical features of MTX syndrome together with new features to expand the phenotype. CASE: A 29-year-old woman decided to terminate her unwanted pregnancy because of ill health, as she had conceived soon after her last delivery by cesarian section. At 6 weeks of gestation, she took 2.5 mg of MTX 3 times a day for 7 days. The pregnancy termination failed, and the pregnancy was carried to term. A female infant was delivered who was growth retarded and had characteristic features of MTX embryopathy in addition to holoprosencephaly and other brain malformations, facial hypertrichosis, and long eyelashes-features that have not hitherto been described. CONCLUSIONS: We report the first case of holoprosencephaly in association with MTX exposure during the first 6 weeks of gestation. Physicians and the public should be aware of the effects of MTX on the fetus during pregnancy.     

Role of NF-kappaB signaling pathway in increased tumor necrosis factor-alpha-induced apoptosis of lymphocytes in aged humans

In human aging, lymphocytes display increased sensitivity to tumor necrosis factor-alpha (TNF-alpha)-induced apoptosis. TNF-alpha induces both survival and apoptotic signals. The survival signal is mediated by the activation of NF-kappaB. Although a role of certain proapoptotic molecules in aging has been reported, a role of altered NF-kappaB signaling pathway has not been explored in detail. In this study, we have compared TNF-alpha-induced activation of NF-kappaB, phosphorylation of IkappaBalpha, and the expression of IKKbeta between lymphocytes from young and aged humans. Furthermore, we have explored a role of IKKbeta in increased susceptibility of lymphocytes from aged humans to TNF-alpha-induced apoptosis. Lymphocytes from aged humans displayed decreased activation of NF-kappaB, reduced phosphorylation of IkappaBalpha, and decreased expression of IKKbeta. In addition, overexpression of IKKbeta in lymphocytes from aged humans normalized TNF-alpha-induced apoptosis to the level of young subjects. These data suggest a deficiency of NF-kappaB signaling pathway and a role of IKKbeta, at least in part, for increased sensitivity of lymphocytes from aged humans to TNF-alpha-induced apoptosis.