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Janinge Henter - One of the best experts on this subject based on the ideXlab platform.
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An N-Terminal Missense Mutation in STX11 Causative of FHL4 Abrogates Syntaxin-11 Binding to Munc18-2.
Frontiers in immunology, 2014Co-Authors: Martha-lena Müller, Bianca Tesi, Marie Meeths, Samuel C. C. Chiang, Stephanie M. Wood, Miriam Entesarian, Magnus Nordenskjold, Janinge Henter, Daniel Nilsson, Ahmed NaqviAbstract:Familial hemophagocytic lymphohistiocytosis (FHL) is an often-fatal hyperinflammatory disorder caused by autosomal recessive mutations in PRF1, UNC13D, STX11, and STXBP2. We identified a homozygous STX11 mutation, c.173T>C (p.L58P), in three patients presenting clinically with hemophagocytic lymphohistiocytosis from unrelated Pakistani families. The mutation yields an amino acid substitution in the N-terminal Habc domain of syntaxin-11 and resulted in defective NK cell degranulation. Notably, syntaxin-11 expression was decreased in patient cells. However, in an ectopic expression system, syntaxin-11 L58P was expressed at levels comparable to wild-type syntaxin-11, but did not bind Munc18-2. Moreover, another N-terminal syntaxin-11 mutant, R4A, also did not bind Munc18-2. Thus, we have identified a novel missense STX11 mutation causative of FHL type 4. The syntaxin-11 R4A and L58P mutations reveal that both the N-terminus and Habc domain of syntaxin-11 are required for binding to Munc18-2, implying similarity to the dynamic binary binding of neuronal syntaxin-1 to Munc18-1.
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characterization of prf1 STX11 and unc13d genotype phenotype correlations in familial hemophagocytic lymphohistiocytosis
British Journal of Haematology, 2008Co-Authors: Annacarin Horne, Eva Rudd, Chengyun Zheng, Kim Ramme, Aytemiz Gurgey, Yasser Wali, Zakia Allamki, Nevin Yalman, Magnus Nordenskjold, Janinge HenterAbstract:SummaryFamilial hemophagocytic lymphohistiocytosis (FHL) is a rare autosomalrecessive lethal condition characterized by fever, cytopenia,hepatosplenomegaly and hemophagocytosis. The hallmark of FHL is defectapoptosis triggering and lymphocyte cellular cytotoxicity. Thus far threedisease-causing genes (PRF1, UNC13D, STX11) have been identified. Weperformed a genotype-phenotype study in a large, multi-ethnic cohort of 76FHL patients originating from 65 unrelated families. Biallelic mutations inPRF1, UNC13D and STX11 were demonstrated in 13/74 (18%), 6/61 (10%)and 14/70 (20%) patients, respectively. In 27/60 (45%) patients analyzed forall three genes, no molecular diagnosis was established. STX11 mutationswere most common in Turkish families (7/28, 25%), whereas in Middle Eastfamilies, PRF1 mutations were most frequent (6/13, 46%). No biallelicmutation was identified in most families of Nordic origin (13/14, 93%).Patients carrying PRF1 mutations had higher risk of early onset (age<6 months) compared to patients carrying STX11 mutations [adjusted oddsratio 8AE23 (95% confidence interval [CI] = 1AE20–56AE40), P =0AE032].Moreover, patients without identified mutations had increased risk ofpathological cerebrospinal fluid (CSF) at diagnosis compared to patients withSTX11 mutations [adjusted odds ratio 26AE37 (CI = 1AE90–366AE82), P =0AE015].These results indicate that the disease-causing mutations in FHL havedifferent phenotypes with regard to ethnic origin, age at onset, andpathological CSF at diagnosis.Keywords: familial hemophagocytic lymphohistiocytosis, phenotype, PRF1,UNC13D, STX11.
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characterization of prf1 STX11 and unc13d genotype phenotype correlations in familial hemophagocytic lymphohistiocytosis
British Journal of Haematology, 2008Co-Authors: Annacarin Horne, Eva Rudd, Chengyun Zheng, Kim Ramme, Aytemiz Gurgey, Yasser Wali, Zakia Allamki, Nevin Yalman, Magnus Nordenskjold, Janinge HenterAbstract:Familial hemophagocytic lymphohistiocytosis (FHL) is a rare autosomal recessive lethal condition characterized by fever, cytopenia, hepatosplenomegaly and hemophagocytosis. The hallmark of FHL is defect apoptosis triggering and lymphocyte cellular cytotoxicity. Thus far three disease-causing genes (PRF1, UNC13D, STX11) have been identified. We performed a genotype-phenotype study in a large, multi-ethnic cohort of 76 FHL patients originating from 65 unrelated families. Biallelic mutations in PRF1, UNC13D and STX11 were demonstrated in 13/74 (18%), 6/61 (10%) and 14/70 (20%) patients, respectively. In 27/60 (45%) patients analyzed for all three genes, no molecular diagnosis was established. STX11 mutations were most common in Turkish families (7/28, 25%), whereas in Middle East families, PRF1 mutations were most frequent (6/13, 46%). No biallelic mutation was identified in most families of Nordic origin (13/14, 93%). Patients carrying PRF1 mutations had higher risk of early onset (age <6 months) compared to patients carrying STX11 mutations [adjusted odds ratio 8.23 (95% confidence interval [CI] = 1.20-56.40), P = 0.032]. Moreover, patients without identified mutations had increased risk of pathological cerebrospinal fluid (CSF) at diagnosis compared to patients with STX11 mutations [adjusted odds ratio 26.37 (CI = 1.90-366.82), P = 0.015]. These results indicate that the disease-causing mutations in FHL have different phenotypes with regard to ethnic origin, age at onset, and pathological CSF at diagnosis.
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linkage of familial hemophagocytic lymphohistiocytosis fhl type 4 to chromosome 6q24 and identification of mutations in syntaxin 11
Human Molecular Genetics, 2005Co-Authors: Udo Zur Stadt, Karin Beutel, Reinhard Schneppenheim, Janinge Henter, Susanne Schmidt, Brigitte Kasper, Sarper A Diler, H Kabisch, Peter NurnbergAbstract:Familial hemophagocytic lymphohistiocytosis (FHL) is a rare autosomal recessive disorder characterized by hyperactive phagocytes and defects in natural killer cell function. It has been shown previously that mutations in the perforin 1 gene (PRF1) and in UNC13D are associated with FHL2 and FHL3, respectively, indicating genetic heterogeneity. We performed genome-wide homozygosity mapping in a large consanguineous Kurdish kindred with five children affected with FHL. Linkage to a 10 cM region on chromosome 6q24 between D6S1569 and D6S960 defined a novel FHL locus. By screening positional candidate genes, we identified a homozygous deletion of 5 bp in the syntaxin 11 gene (STX11) in this family. We could demonstrate that syntaxin 11 protein was absent in the mononuclear cell fraction of patients with the homozygous 5 bp deletion. In addition to this family, we found homozygous mutations in STX11 in five consanguineous Turkish/Kurdish FHL kindreds including two families with the 5 bp deletion, one family with a large 19.2 kb genomic deletion spanning the entire coding region of STX11 (exon 2) and two families with a nonsense mutation that leads to a premature stop codon in the C-terminal end of the protein. As both STX11 and UNC13D are involved in vesicle trafficking and membrane fusion, we conclude that, besides mutations in perforin 1, defects in the endocytotic or the exocytotic pathway may be a common mechanism in FHL.
Kimio Akagawa - One of the best experts on this subject based on the ideXlab platform.
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syntaxin 1a gene is negatively regulated in a cell tissue specific manner by yy1 transcription factor which binds to the 183 to 137 promoter region together with gene silencing factors including histone deacetylase
Biomolecules, 2021Co-Authors: Takahiro Nakayama, Toshiyuki Fukutomi, Yasuo Terao, Kimio AkagawaAbstract:The HPC-1/syntaxin 1A (Stx1a) gene, which is involved in synaptic transmission and neurodevelopmental disorders, is a TATA-less gene with several transcription start sites. It is activated by the binding of Sp1 and acetylated histone H3 to the −204 to +2 core promoter region (CPR) in neuronal cell/tissue. Furthermore, it is depressed by the association of class 1 histone deacetylases (HDACs) to Stx1a–CPR in non-neuronal cell/tissue. To further clarify the factors characterizing Stx1a gene silencing in non-neuronal cell/tissue not expressing Stx1a, we attempted to identify the promoter region forming DNA–protein complex only in non-neuronal cells. Electrophoresis mobility shift assays (EMSA) demonstrated that the −183 to −137 OL2 promoter region forms DNA–protein complex only in non-neuronal fetal rat skin keratinocyte (FRSK) cells which do not express Stx1a. Furthermore, the Yin-Yang 1 (YY1) transcription factor binds to the −183 to −137 promoter region of Stx1a in FRSK cells, as shown by competitive EMSA and supershift assay. Chromatin immunoprecipitation assay revealed that YY1 in vivo associates to Stx1a–CPR in cell/tissue not expressing Stx1a and that trichostatin A treatment in FRSK cells decreases the high-level association of YY1 to Stx1a-CPR in default. Reporter assay indicated that YY1 negatively regulates Stx1a transcription. Finally, mass spectrometry analysis showed that gene silencing factors, including HDAC1, associate onto the −183 to −137 promoter region together with YY1. The current study is the first to report that Stx1a transcription is negatively regulated in a cell/tissue-specific manner by YY1 transcription factor, which binds to the −183 to −137 promoter region together with gene silencing factors, including HDAC.
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syntaxin 1b contributes to regulation of the dopaminergic system through gaba transmission in the cns
European Journal of Neuroscience, 2017Co-Authors: Tomonori Fujiwara, Tatsuya Mishima, Takefumi Kofuji, Kimio AkagawaAbstract:In neuronal plasma membrane, two syntaxin isoforms, HPC-1/syntaxin 1A (STX1A) and syntaxin 1B (STX1B), are predominantly expressed as soluble N-ethylmaleimide-sensitive fusion attachment protein receptors, also known as t-SNAREs. We previously reported that glutamatergic and GABAergic synaptic transmissions are impaired in Stx1b null mutant (Stx1b-/- ) mice but are almost normal in Stx1a null mutant (Stx1a-/- ) mice. These observations suggested that STX1A and STX1B have distinct functions in fast synaptic transmission in the central nervous system (CNS). Interestingly, recent studies indicated that Stx1a-/- or Stx1a+/- mice exhibit disruption in the monoaminergic system in the CNS, causing unusual behaviour that is similar to neuropsychological alterations observed in psychiatric patients. Here, we studied whether STX1B contributes to the regulation of monoaminergic system and if STX1B is related to neuropsychological properties in human neuropsychological disorders similar to STX1A. We found that monoamine release in vitro was normal in Stx1b+/- mice unlike Stx1a-/- or Stx1a+/- mice, but the basal extracellular dopamine (DA) concentration in the ventral striatum was increased. DA secretion in the ventral striatum is regulated by GABAergic neurons, and Stx1b+/- mice exhibited reduced GABA release both in vitro and in vivo, disrupting the DAergic system in the CNS of these mice. We also found that Stx1b+/- mice exhibited reduced pre-pulse inhibition (PPI), which is believed to represent one of the prominent schizotypal behavioural profiles of human psychiatric patients. The reduction in PPI was rescued by DA receptor antagonists. These observations indicated that STX1B contributes to excess activity of the DAergic system through regulation of GABAergic transmission.
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a part of patients with autism spectrum disorder has haploidy of hpc 1 syntaxin1a gene that possibly causes behavioral disturbance as in experimentally gene ablated mice
Neuroscience Letters, 2017Co-Authors: Takefumi Kofuji, Tomonori Fujiwara, Masumi Sanada, Yuko Hayashi, Masao Tamaru, Kimio AkagawaAbstract:Autism spectrum disorder (ASD) is highly heritable and encompasses a various set of neuropsychiatric disorders with a wide-ranging presentation. HPC-1/syntaxin1A (STX1A) encodes a neuronal plasma membrane protein that regulates the secretion of neurotransmitters and neuromodulators. STX1A gene ablated mice (null and heterozygote mutant) exhibit abnormal behavioral profiles similar to human autistic symptoms, accompanied by reduction of monoamine secretion. To determine whether copy number variation of STX1A gene and the change of its expression correlate with ASD as in STX1A gene ablated mice, we performed copy number assay and real-time quantitative RT-PCR using blood or saliva samples from ASD patients. We found that some ASD patients were haploid for the STX1A gene similar to STX1A heterozygote mutant mice. However, copy number of STX1A gene was normal in the parents and siblings of ASD patients with STX1A gene haploidy. In ASD patients with gene haploidy, STX1A mRNA expression was reduced to about half of their parents. Thus, a part of ASD patients had haploidy of STX1A gene and lower STX1A gene expression.
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unusual social behavior in hpc 1 syntaxin1a knockout mice is caused by disruption of the oxytocinergic neural system
Journal of Neurochemistry, 2016Co-Authors: Tomonori Fujiwara, Masumi Sanada, Takefumi Kofuji, Kimio AkagawaAbstract:HPC-1/syntaxin1A (STX1A), a neuronal soluble N-ethylmaleimide-sensitive fusion attachment protein receptor, contributes to neural function in the CNS by regulating transmitter release. Recent studies reported that STX1A is associated with human neuropsychological disorders, such as autism spectrum disorder and attention deficit hyperactivity disorder. Previously, we showed that STX1A null mutant mice (STX1A KO) exhibit neuropsychological abnormalities, such as fear memory deficits, attenuation of latent inhibition, and unusual social behavior. These observations suggested that STX1A may be involved in the neuropsychological basis of these abnormalities. Here, to study the neural basis of social behavior, we analyzed the profile of unusual social behavior in STX1A KO with a social novelty preference test, which is a useful method for quantification of social behavior. Interestingly, the unusual social behavior in STX1A KO was partially rescued by intracerebroventricular administration of oxytocin (OXT). In vivo microdialysis studies revealed that the extracellular OXT concentration in the CNS of STX1A KO was significantly lower compared with wild-type mice. Furthermore, dopamine-induced OXT release was reduced in STX1A KO. These results suggested that STX1A plays an important role in social behavior through regulation of the OXTergic neural system. Dopamine (DA) release is reduced in CNS of syntaxin1A null mutant mice (STX1A KO). Unusual social behavior was observed in STX1A KO. We found that oxytocin (OXT) release, which was stimulated by DA, was reduced and was rescued the unusual social behavior in STX1A KO was rescued by OXT. These results indicated that STX1A plays an important role in promoting social behavior through regulation of DA-induced OXT release in amygdala.
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HPC-1/syntaxin 1A and syntaxin 1B play distinct roles in neuronal survival.
Journal of neurochemistry, 2014Co-Authors: Takefumi Kofuji, Tatsuya Mishima, Tomonori Fujiwara, Masumi Sanada, Kimio AkagawaAbstract:Two types of syntaxin 1 isoforms, HPC-1/syntaxin 1A (STX1A) and syntaxin 1B (STX1B), are thought to have similar functions in exocytosis of synaptic vesicles. STX1A(-/-) mice which we generated previously develop normally, possibly because of compensation by STX1B. We produced STX1B(-/-) mice using targeted gene disruption and investigated their phenotypes. STX1B(-/-) mice were born alive, but died before postnatal day 14, unlike STX1A(-/-) mice. Morphologically, brain development in STX1B(-/-) mice was impaired. In hippocampal neuronal culture, the cell viability of STX1B(-/-) neurons was lower than that of WT or STX1A(-/-) neurons after 9 days. Interestingly, STX1B(-/-) neurons survived on WT or STX1A(-/-) glial feeder layers as well as WT neurons. However, STX1B(-/-) glial feeder layers were less effective at promoting survival of STX1B(-/-) neurons. Conditioned medium from WT or STX1A(-/-) glial cells had a similar effect on survival, but that from STX1B(-/-) did not promote survival. Furthermore, brain-derived neurotrophic factor (BDNF) or neurotrophin-3 supported survival of STX1B(-/-) neurons. BDNF localization in STX1B(-/-) glial cells was disrupted, and BDNF secretion from STX1B(-/-) glial cells was impaired. These results suggest that STX1A and STX1B may play distinct roles in supporting neuronal survival by glia. Syntaxin 1A (STX1A) and syntaxin 1B (STX1B) are thought to have similar functions as SNARE proteins. However, we found that STX1A and STX1B play distinct roles in neuronal survival using STX1A(-/-) mice and STX1B(-/-) mice. STX1B was important for neuronal survival, possibly by regulating the secretion of neurotrophic factors, such as BDNF, from glial cells.
Magnus Nordenskjold - One of the best experts on this subject based on the ideXlab platform.
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An N-Terminal Missense Mutation in STX11 Causative of FHL4 Abrogates Syntaxin-11 Binding to Munc18-2.
Frontiers in immunology, 2014Co-Authors: Martha-lena Müller, Bianca Tesi, Marie Meeths, Samuel C. C. Chiang, Stephanie M. Wood, Miriam Entesarian, Magnus Nordenskjold, Janinge Henter, Daniel Nilsson, Ahmed NaqviAbstract:Familial hemophagocytic lymphohistiocytosis (FHL) is an often-fatal hyperinflammatory disorder caused by autosomal recessive mutations in PRF1, UNC13D, STX11, and STXBP2. We identified a homozygous STX11 mutation, c.173T>C (p.L58P), in three patients presenting clinically with hemophagocytic lymphohistiocytosis from unrelated Pakistani families. The mutation yields an amino acid substitution in the N-terminal Habc domain of syntaxin-11 and resulted in defective NK cell degranulation. Notably, syntaxin-11 expression was decreased in patient cells. However, in an ectopic expression system, syntaxin-11 L58P was expressed at levels comparable to wild-type syntaxin-11, but did not bind Munc18-2. Moreover, another N-terminal syntaxin-11 mutant, R4A, also did not bind Munc18-2. Thus, we have identified a novel missense STX11 mutation causative of FHL type 4. The syntaxin-11 R4A and L58P mutations reveal that both the N-terminus and Habc domain of syntaxin-11 are required for binding to Munc18-2, implying similarity to the dynamic binary binding of neuronal syntaxin-1 to Munc18-1.
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characterization of prf1 STX11 and unc13d genotype phenotype correlations in familial hemophagocytic lymphohistiocytosis
British Journal of Haematology, 2008Co-Authors: Annacarin Horne, Eva Rudd, Chengyun Zheng, Kim Ramme, Aytemiz Gurgey, Yasser Wali, Zakia Allamki, Nevin Yalman, Magnus Nordenskjold, Janinge HenterAbstract:SummaryFamilial hemophagocytic lymphohistiocytosis (FHL) is a rare autosomalrecessive lethal condition characterized by fever, cytopenia,hepatosplenomegaly and hemophagocytosis. The hallmark of FHL is defectapoptosis triggering and lymphocyte cellular cytotoxicity. Thus far threedisease-causing genes (PRF1, UNC13D, STX11) have been identified. Weperformed a genotype-phenotype study in a large, multi-ethnic cohort of 76FHL patients originating from 65 unrelated families. Biallelic mutations inPRF1, UNC13D and STX11 were demonstrated in 13/74 (18%), 6/61 (10%)and 14/70 (20%) patients, respectively. In 27/60 (45%) patients analyzed forall three genes, no molecular diagnosis was established. STX11 mutationswere most common in Turkish families (7/28, 25%), whereas in Middle Eastfamilies, PRF1 mutations were most frequent (6/13, 46%). No biallelicmutation was identified in most families of Nordic origin (13/14, 93%).Patients carrying PRF1 mutations had higher risk of early onset (age<6 months) compared to patients carrying STX11 mutations [adjusted oddsratio 8AE23 (95% confidence interval [CI] = 1AE20–56AE40), P =0AE032].Moreover, patients without identified mutations had increased risk ofpathological cerebrospinal fluid (CSF) at diagnosis compared to patients withSTX11 mutations [adjusted odds ratio 26AE37 (CI = 1AE90–366AE82), P =0AE015].These results indicate that the disease-causing mutations in FHL havedifferent phenotypes with regard to ethnic origin, age at onset, andpathological CSF at diagnosis.Keywords: familial hemophagocytic lymphohistiocytosis, phenotype, PRF1,UNC13D, STX11.
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characterization of prf1 STX11 and unc13d genotype phenotype correlations in familial hemophagocytic lymphohistiocytosis
British Journal of Haematology, 2008Co-Authors: Annacarin Horne, Eva Rudd, Chengyun Zheng, Kim Ramme, Aytemiz Gurgey, Yasser Wali, Zakia Allamki, Nevin Yalman, Magnus Nordenskjold, Janinge HenterAbstract:Familial hemophagocytic lymphohistiocytosis (FHL) is a rare autosomal recessive lethal condition characterized by fever, cytopenia, hepatosplenomegaly and hemophagocytosis. The hallmark of FHL is defect apoptosis triggering and lymphocyte cellular cytotoxicity. Thus far three disease-causing genes (PRF1, UNC13D, STX11) have been identified. We performed a genotype-phenotype study in a large, multi-ethnic cohort of 76 FHL patients originating from 65 unrelated families. Biallelic mutations in PRF1, UNC13D and STX11 were demonstrated in 13/74 (18%), 6/61 (10%) and 14/70 (20%) patients, respectively. In 27/60 (45%) patients analyzed for all three genes, no molecular diagnosis was established. STX11 mutations were most common in Turkish families (7/28, 25%), whereas in Middle East families, PRF1 mutations were most frequent (6/13, 46%). No biallelic mutation was identified in most families of Nordic origin (13/14, 93%). Patients carrying PRF1 mutations had higher risk of early onset (age <6 months) compared to patients carrying STX11 mutations [adjusted odds ratio 8.23 (95% confidence interval [CI] = 1.20-56.40), P = 0.032]. Moreover, patients without identified mutations had increased risk of pathological cerebrospinal fluid (CSF) at diagnosis compared to patients with STX11 mutations [adjusted odds ratio 26.37 (CI = 1.90-366.82), P = 0.015]. These results indicate that the disease-causing mutations in FHL have different phenotypes with regard to ethnic origin, age at onset, and pathological CSF at diagnosis.
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spectrum and clinical implications of syntaxin 11 gene mutations in familial haemophagocytic lymphohistiocytosis association with disease free remissions and haematopoietic malignancies
Journal of Medical Genetics, 2005Co-Authors: Eva Rudd, Chengyun Zheng, Aytemiz Gurgey, Magnus Nordenskjold, Goransdotter K Ericson, Z Uysal, A Ozkan, Bengt Fadeel, Ji HenterAbstract:Objective: To determine the frequency and spectrum of mutations in the gene encoding syntaxin 11 ( STX11 ) in familial haemophagocytic lymphohistiocytosis (FHL), a rare autosomal recessive disorder of immune dysregulation characterised by a defect in natural killer cell function. Methods: Mutational analysis of STX11 by direct sequencing was done in 28 FHL families that did not harbour perforin mutations, previously identified in some FHL patients. A detailed investigation of clinical features of these patients was also undertaken. Results: Two different STX11 mutations were identified, one nonsense mutation and one deletion, affecting six of 34 children in four of 28 unrelated PRF1 negative families. Both mutations have been reported before. Three patients experienced long periods (⩾1 year) in remission without specific treatment, which is very uncommon in this disease. Despite the milder phenotype, some children with STX11 mutations developed severe psychomotor retardation. Two of the six patients harbouring STX11 gene defects developed myelodysplastic syndrome (MDS) or acute myelogenous leukaemia (AML). Conclusions: STX11 gene mutations were found in 14% of the PRF1 negative FHL families included in the present cohort. These results suggest that STX11 gene mutations may be associated with secondary malignancies (MDS/AML), and that there is segregation of specific clinical features in FHL patients with an underlying genotype.
Yasuyuki Imai - One of the best experts on this subject based on the ideXlab platform.
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production of hybrid igg iga plantibodies with neutralizing activity against shiga toxin 1
PLOS ONE, 2013Co-Authors: Katsuhiro Nakanishi, Sanshiro Narimatsu, Shiori Ichikawa, Yasuo Niwa, Yuki Tobisawa, Hirokazu Kobayashi, Kohta Kurohane, Yasuyuki ImaiAbstract:Shiga toxin 1 (Stx1) is a virulence factor of enterohemorrhagic Escherichia coli, such as the O157:H7 strain. In the intestines, secretory IgA (SIgA) is a major component of the immune defense against pathogens and toxins. To form SIgA, the production of dimeric IgA that retains biological activity is an important step. We previously established hybrid-IgG/IgA having variable regions of the IgG specific for the binding subunit of Stx1 (Stx1B) and the heavy chain constant region of IgA. If hybrid-IgG/IgA cDNAs can be expressed in plants, therapeutic or preventive effects may be expected in people eating those plants containing a “plantibody”. Here, we established transgenic Arabidopsis thaliana expressing dimeric hybrid-IgG/IgA. The heavy and light chain genes were placed under the control of a bidirectional promoter and terminator of the chlorophyll a/b-binding protein of Arabidopsis thaliana (expression cassette). This expression cassette and the J chain gene were subcloned into a single binary vector, which was then introduced into A. thaliana by means of the Agrobacterium method. Expression and assembly of the dimeric hybrid-IgG/IgA in plants were revealed by ELISA and immunoblotting. The hybrid-IgG/IgA bound to Stx1B and inhibited Stx1B binding to Gb3, as demonstrated by ELISA. When Stx1 holotoxin was pre-treated with the resulting plantibody, the cytotoxicity of Stx1 was inhibited. The toxin neutralization was also demonstrated by means of several assays including Stx1-induced phosphatidylserine translocation on the plasma membrane, caspase-3 activation and 180 base-pair DNA ladder formation due to inter-nucleosomal cleavage. These results indicate that edible plants containing hybrid-IgG/IgA against Stx1B have the potential to be used for immunotherapy against Stx1-caused food poisoning.
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Production of Hybrid-IgG/IgA Plantibodies with Neutralizing Activity against Shiga Toxin 1
PLOS ONE, 2013Co-Authors: Katsuhiro Nakanishi, Sanshiro Narimatsu, Shiori Ichikawa, Yasuo Niwa, Yuki Tobisawa, Hirokazu Kobayashi, Kohta Kurohane, Yasuyuki ImaiAbstract:Shiga toxin 1 (Stx1) is a virulence factor of enterohemorrhagic Escherichia coli, such as the O157:H7 strain. In the intestines, secretory IgA (SIgA) is a major component of the immune defense against pathogens and toxins. To form SIgA, the production of dimeric IgA that retains biological activity is an important step. We previously established hybrid-IgG/IgA having variable regions of the IgG specific for the binding subunit of Stx1 (Stx1B) and the heavy chain constant region of IgA. If hybrid-IgG/IgA cDNAs can be expressed in plants, therapeutic or preventive effects may be expected in people eating those plants containing a “plantibody”. Here, we established transgenic Arabidopsis thaliana expressing dimeric hybrid-IgG/IgA. The heavy and light chain genes were placed under the control of a bidirectional promoter and terminator of the chlorophyll a/b-binding protein of Arabidopsis thaliana (expression cassette). This expression cassette and the J chain gene were subcloned into a single binary vector, which was then introduced into A. thaliana by means of the Agrobacterium method. Expression and assembly of the dimeric hybrid-IgG/IgA in plants were revealed by ELISA and immunoblotting. The hybrid-IgG/IgA bound to Stx1B and inhibited Stx1B binding to Gb3, as demonstrated by ELISA. When Stx1 holotoxin was pre-treated with the resulting plantibody, the cytotoxicity of Stx1 was inhibited. The toxin neutralization was also demonstrated by means of several assays including Stx1-induced phosphatidylserine translocation on the plasma membrane, caspase-3 activation and 180 base-pair DNA ladder formation due to inter-nucleosomal cleavage. These results indicate that edible plants containing hybrid-IgG/IgA against Stx1B have the potential to be used for immunotherapy against Stx1-caused food poisoning.
Michael Wegner - One of the best experts on this subject based on the ideXlab platform.
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anterior segment dysgenesis in the eyes of mice deficient for the high mobility group transcription factor sox11
Experimental Eye Research, 2008Co-Authors: Antje Wurm, Elisabeth Sock, Rudolf Fuchshofer, Michael Wegner, Ernst R TammAbstract:Abstract We describe that Sox11, a member of the group C of the Sox transcription factor family, is critically required during the morphogenetic processes of early eye development, and that lack of Sox11 results in ocular anterior segment dysgenesis (ASD). Sox11 -deficient mice show a persistent lens stalk, a delay in lens formation, and the phenotypes of Peters' anomaly and microphthalmia at birth. In addition, the optic fissure does not close in the anterior halves of the eyes resulting in anterior coloboma. The delay in lens formation is associated with a reduced mitotic activity in the lens placode during its invagination into the optic cup. No changes in Pax6 expression are observed in the developing eyes of Sox11 −/− mice, whereas the expression of Sox11 is reduced in optic cup, optic vesicle and lens placode of Pax6 + / − embryos and in the optic vesicle of Pax6 −/− mice. Transfection experiments show an increase in Sox11 expression when higher doses of Pax6 are present. Considerably smaller amounts of BMP7 are expressed in lens and optic cup of Sox11 −/− mice as compared to their wild-type littermates. We conclude that Sox11 is required during separation of the lens vesicle from the surface ectoderm and the closure of the anterior optic fissure. The expression of Sox11 in early eye development is under control of Pax6, and changes in BMP7-signalling appear to be involved in the effects of Sox11 on anterior eye development. Our findings suggest that SOX11 might similarly be involved in the pathogenesis of ASD in human patients.
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gene targeting reveals a widespread role for the high mobility group transcription factor sox11 in tissue remodeling
Molecular and Cellular Biology, 2004Co-Authors: Elisabeth Sock, Ernst R Tamm, Stefanie D Rettig, Janna Enderich, Michael R Bosl, Michael WegnerAbstract:The high-mobility-group domain-containing transcription factor Sox11 is expressed transiently during embryonic development in many tissues that undergo inductive remodeling. Here we have analyzed the function of Sox11 by gene deletion in the mouse. Sox11-deficient mice died at birth from congenital cyanosis, likely resulting from heart defects. These included ventricular septation defects and outflow tract malformations that ranged from arterial common trunk to a condition known as double outlet right ventricle. Many other organs that normally express Sox11 also exhibited severe developmental defects. We observed various craniofacial and skeletal malformations, asplenia, and hypoplasia of the lung, stomach, and pancreas. Eyelids and the abdominal wall did not close properly in some Sox11-deficient mice. This phenotype suggests a prime function for Sox11 in tissue remodeling and identifies SOX11 as a potentially mutated gene in corresponding human malformation syndromes.
