The Experts below are selected from a list of 153 Experts worldwide ranked by ideXlab platform
S. Porubsky - One of the best experts on this subject based on the ideXlab platform.
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Globosides as key players in the pathophysiology of Shiga toxin-associated acute kidney failure and Fabry disease
Der Pathologe, 2020Co-Authors: S. PorubskyAbstract:Globosides and their isomeric counterparts isoGlobosides belong to the class of neutral glycosphingolipids with an as yet undefined physiological function. In the pathogenesis of human diseases, Globosides play an important role as cellular receptors for Shiga toxins which are produced by certain strains of S. dysenteriae and E. coli. In order to elucidate the pathogenesis of Shiga toxin-associated kidney failure, we studied human kidney biopsies and animal models. Our work showed that in patients suffering from Shiga toxin-elicited kidney failure, no complement activation could be demonstrated by immunohistochemical analysis of kidney biopsies. Therefore, complement activation is unlikely to play a major role in mediating thrombotic microangiopathy on exposure to Shiga toxin. Moreover, analysis of the human biopsies and of a murine model of Shiga toxin-associated disease pinpointed acute tubular damage as an important and previously neglected contributor to acute kidney failure in patients infected with Shiga toxin-producing E. coli. Furthermore, Globosides play a decisive role in the pathogenesis of Fabry disease which results from a decreased or absent activity of the lysosomal enzyme α-galactosidase A. The results on transgenic mice showed that in vital organs, such as the heart, kidneys and liver, it was possible to revert the phenotype of Fabry disease by eliminating the synthesis of Globosides. This implicates that substrate reduction therapy through inhibition of Globosides might represent a new therapeutic option for Fabry disease, all the more so as Globosides seem to be dispensable.
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Globoside als entscheidende Mediatoren in der Pathophysiologie des Shiga-Toxin-assoziierten akuten Nierenversagens und des Morbus Fabry
Der Pathologe, 2014Co-Authors: S. PorubskyAbstract:Globoside und ihre Isomere Isogloboside gehören zu neutralen Glykosphingolipiden, deren physiologische Funktion noch nicht geklärt ist. In der Pathogenese humaner Erkrankungen spielen Globoside eine wichtige Rolle als zelluläre Rezeptoren für Shiga-Toxine, die von einigen Stämmen der S. dysenteriae und E. coli produziert werden. Um die Pathogenese des Shiga-Toxin-assoziierten Nierenversagens zu klären, untersuchten wir Nierenbiopsien und Tiermodelle. Unsere Ergebnisse zeigten, dass bei Patienten mit Shiga-Toxin-assoziiertem Nierenversagen histologisch keine Komplementaktivierung nachweisbar war. Diese scheint daher in die Pathogenese der thrombotischen Mikroangiopathie nicht involviert zu sein. Vielmehr konnten wir anhand der Nierenbiopsien und Tiermodelle zeigen, dass ein akuter Tubulusschaden einen wichtigen und bislang wahrscheinlich verkannten Beitrag zum Shiga-Toxin-assoziierten Nierenversagen leistet. Des Weiteren spielen Globoside eine entscheidende Rolle in der Pathogenese des Morbus Fabry, welcher als Folge einer verminderten oder fehlenden Aktivität des lysosomalen Enzyms α-Galaktosidase A entsteht. Unsere Ergebnisse an transgenen Mäusen zeigten, dass es in den lebenswichtigen Organen wie Herz, Leber und Niere möglich war, den Phänotyp des Morbus Fabry durch die Elimination von Globosiden zu beseitigen. Eine Substratreduktionstherapie durch Inhibition der Synthese von Globosiden kann demzufolge eine neue therapeutische Option für den Morbus Fabry darstellen, insbesondere weil Globoside als entbehrlich erscheinen. Globosides and their isomeric counterparts isoGlobosides belong to the class of neutral glycosphingolipids with an as yet undefined physiological function. In the pathogenesis of human diseases, Globosides play an important role as cellular receptors for Shiga toxins which are produced by certain strains of S. dysenteriae and E. coli . In order to elucidate the pathogenesis of Shiga toxin-associated kidney failure, we studied human kidney biopsies and animal models. Our work showed that in patients suffering from Shiga toxin-elicited kidney failure, no complement activation could be demonstrated by immunohistochemical analysis of kidney biopsies. Therefore, complement activation is unlikely to play a major role in mediating thrombotic microangiopathy on exposure to Shiga toxin. Moreover, analysis of the human biopsies and of a murine model of Shiga toxin-associated disease pinpointed acute tubular damage as an important and previously neglected contributor to acute kidney failure in patients infected with Shiga toxin-producing E. coli . Furthermore, Globosides play a decisive role in the pathogenesis of Fabry disease which results from a decreased or absent activity of the lysosomal enzyme α-galactosidase A. The results on transgenic mice showed that in vital organs, such as the heart, kidneys and liver, it was possible to revert the phenotype of Fabry disease by eliminating the synthesis of Globosides. This implicates that substrate reduction therapy through inhibition of Globosides might represent a new therapeutic option for Fabry disease, all the more so as Globosides seem to be dispensable.
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Globoside als entscheidende Mediatoren in der Pathophysiologie des Shiga-Toxin-assoziierten akuten Nierenversagens und des Morbus Fabry
Pathologe, 2014Co-Authors: S. PorubskyAbstract:Globoside und ihre Isomere Isogloboside gehoren zu neutralen Glykosphingolipiden, deren physiologische Funktion noch nicht geklart ist. In der Pathogenese humaner Erkrankungen spielen Globoside eine wichtige Rolle als zellulare Rezeptoren fur Shiga-Toxine, die von einigen Stammen der S. dysenteriae und E. coli produziert werden. Um die Pathogenese des Shiga-Toxin-assoziierten Nierenversagens zu klaren, untersuchten wir Nierenbiopsien und Tiermodelle. Unsere Ergebnisse zeigten, dass bei Patienten mit Shiga-Toxin-assoziiertem Nierenversagen histologisch keine Komplementaktivierung nachweisbar war. Diese scheint daher in die Pathogenese der thrombotischen Mikroangiopathie nicht involviert zu sein. Vielmehr konnten wir anhand der Nierenbiopsien und Tiermodelle zeigen, dass ein akuter Tubulusschaden einen wichtigen und bislang wahrscheinlich verkannten Beitrag zum Shiga-Toxin-assoziierten Nierenversagen leistet. Des Weiteren spielen Globoside eine entscheidende Rolle in der Pathogenese des Morbus Fabry, welcher als Folge einer verminderten oder fehlenden Aktivitat des lysosomalen Enzyms α-Galaktosidase A entsteht. Unsere Ergebnisse an transgenen Mausen zeigten, dass es in den lebenswichtigen Organen wie Herz, Leber und Niere moglich war, den Phanotyp des Morbus Fabry durch die Elimination von Globosiden zu beseitigen. Eine Substratreduktionstherapie durch Inhibition der Synthese von Globosiden kann demzufolge eine neue therapeutische Option fur den Morbus Fabry darstellen, insbesondere weil Globoside als entbehrlich erscheinen.
Koichi Furukawa - One of the best experts on this subject based on the ideXlab platform.
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Expression Cloning of Human Globoside Synthase cDNAs
2020Co-Authors: Tetsuya Okajima, Yoko Nakamura, Makoto Uchikawa, David B Haslam, Shinichiro Numata, Keiko Furukawa, Takeshi Urano, Koichi FurukawaAbstract:By using a eukaryocytic cell expression cloning system, we have isolated cDNAs of the globoside synthase (b1,3-N-acetylgalactosaminyltransferase) gene. Mouse fibroblast L cells transfected with SV40 large T antigen and previously cloned Gb3/CD77 synthase cDNAs were co-transfected with a cDNA library prepared from mRNA from human kidney together with Forssman synthase cDNA, and Forssman antigen-positive cells were panned using an anti-Forssman monoclonal antibody. The isolated cDNAs contained a single open reading frame predicting a type II membrane protein with 351 amino acids. Surprisingly, the cDNA clones turned out to be identical with previously reported b3Gal-T3, which had been cloned by sequence homology with other galactosyltransferases. Substrate specificity analysis with extracts from cDNA-transfected L cells confirmed that the gene product was actually b1,3-N-acetylgalactosaminyltransferase that specifically catalyzes the transfer of N-acetylgalactosamine onto globotriaosylceramide. Results of TLC immunostaining of neutral glycolipids from the cDNA-transfected cells also supported the identity of the newly synthesized component as globoside. The results show that glycosyltransferases apparently belonging to a single glycosyltransferase family do not necessarily catalyze reactions utilizing the same acceptor or even the same sugar donor. The globoside synthase gene was expressed in many tissues, such as heart, brain, testis, etc. We propose the designation b3GalNAc-T1 for the cloned globoside synthase gene.
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expression cloning of human globoside synthase cdnas identification of β3gal t3 as udp n acetylgalactosamine globotriaosylceramide β1 3 n acetylgalactosaminyltransferase
Journal of Biological Chemistry, 2000Co-Authors: Tetsuya Okajima, Yoko Nakamura, Makoto Uchikawa, David B Haslam, Shinichiro Numata, Keiko Furukawa, Takeshi Urano, Koichi FurukawaAbstract:Next Section Abstract By using a eukaryocytic cell expression cloning system, we have isolated cDNAs of the globoside synthase (β1,3-N-acetylgalactosaminyltransferase) gene. Mouse fibroblast L cells transfected with SV40 large T antigen and previously cloned Gb3/CD77 synthase cDNAs were co-transfected with a cDNA library prepared from mRNA from human kidney together with Forssman synthase cDNA, and Forssman antigen-positive cells were panned using an anti-Forssman monoclonal antibody. The isolated cDNAs contained a single open reading frame predicting a type II membrane protein with 351 amino acids. Surprisingly, the cDNA clones turned out to be identical with previously reported β3Gal-T3, which had been cloned by sequence homology with other galactosyltransferases. Substrate specificity analysis with extracts from cDNA-transfected L cells confirmed that the gene product was actually β1,3-N-acetylgalactosaminyltransferase that specifically catalyzes the transfer of N-acetylgalactosamine onto globotriaosylceramide. Results of TLC immunostaining of neutral glycolipids from the cDNA-transfected cells also supported the identity of the newly synthesized component as globoside. The results show that glycosyltransferases apparently belonging to a single glycosyltransferase family do not necessarily catalyze reactions utilizing the same acceptor or even the same sugar donor. The globoside synthase gene was expressed in many tissues, such as heart, brain, testis, etc. We propose the designation β3GalNAc-T1 for the cloned globoside synthase gene.
Stefan Porubsky - One of the best experts on this subject based on the ideXlab platform.
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Depletion of Globosides and isoGlobosides fully reverts the morphologic phenotype of Fabry disease.
Cell and Tissue Research, 2014Co-Authors: Stefan Porubsky, Lorenz H Lehmann, Richard Jennemann, Hermann Josef GroneAbstract:Fabry disease is a monogenic X-linked lysosomal storage disease caused by α-galactosidase A (αGalA) deficiency. Enzyme replacement therapy through administration of the missing αGalA is currently the only accepted therapeutic option. However, this treatment is connected to high costs, has ill-defined indication criteria and its efficacy is controversially discussed. Our aim was to explore the possibility of a novel targeted substrate reduction therapy for Fabry disease. Owing to the fact that αGalA-deficient humans and mice accumulate the same glycosphingolipids (i.e. Globosides, galabiosylceramide and isoGlobosides), αGalA-deficient mice were crossed with mice deficient in enzymes synthesizing these classes of glycosphingolipids (i.e. globotrihexosylceramide and isoglobotrihexosylceramide synthase, respectively). Functional heart and kidney tests were performed together with an extensive biochemical analysis of urine and serum in aged mice. Lysosomal storage was assessed by thin layer chromatography and electron microscopy. We showed that depletion of Globosides was sufficient to fully abolish the storage of glycosphingolipids in heart, kidney and liver and was paralleled by a complete restoration of lysosomal morphology in these organs. In contrast, in dorsal root ganglia, a depletion of both Globosides and isoGlobosides was necessary to fully counteract the lysosomal storage. The deficiency in Globosides and/or isoGlobosides did not cause any adverse effects. We conclude that substrate reduction therapy through inhibition of the synthesis of Globosides and isoGlobosides represents a valuable therapeutic option for Fabry disease, all the more as Globosides and isoGlobosides seem to be dispensable.
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Globosides but not isoGlobosides can impact the development of invariant nkt cells and their interaction with dendritic cells
Journal of Immunology, 2012Co-Authors: Stefan Porubsky, Richard Jennemann, Anneliese O Speak, Mariolina Salio, Mahnaz Bonrouhi, Rashad Zafarulla, Yogesh Singh, Julian Dyson, Bruno LuckowAbstract:Recognition of endogenous lipid Ag(s) on CD1d is required for the development of invariant NKT (iNKT) cells. Isoglobotrihexosylceramide (iGb3) has been implicated as this endogenous selecting ligand and recently suggested to control overstimulation and deletion of iNKT cells in α-galactosidase A-deficient ( αGalA−/− ) mice (human Fabry disease), which accumulate isoGlobosides and Globosides. However, the presence and function of iGb3 in murine thymus remained controversial. In this study, we generate a globotrihexosylceramide (Gb3)‑synthase-deficient ( Gb3S−/− ) mouse and show that in thymi of αGalA−/−/Gb3S−/− double-knockout mice, which store isoGlobosides but no Globosides, minute amounts of iGb3 can be detected by HPLC. Furthermore, we demonstrate that iGb3 deficiency does not only fail to impact selection of iNKT cells, in terms of frequency and absolute numbers, but also does not alter the distribution of the TCR CDR 3 of iNKT cells. Analyzing multiple gene-targeted mouse strains, we demonstrate that globoside, rather than iGb3, storage is the major cause for reduced iNKT cell frequencies and defective Ag presentation in αGalA−/− mice. Finally, we show that correction of globoside storage in αGalA−/− mice by crossing them with Gb3S−/− normalizes iNKT cell frequencies and dendritic cell (DC) function. We conclude that, although detectable in murine thymus in αGalA−/−/Gb3S−/− mice, iGb3 does not influence either the development of iNKT cells or their interaction with peripheral DCs. Moreover, in αGalA−/− mice, it is the Gb3 storage that is responsible for the decreased iNKT cell numbers and impeded Ag presentation on DCs.
Tetsuya Okajima - One of the best experts on this subject based on the ideXlab platform.
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Expression Cloning of Human Globoside Synthase cDNAs
2020Co-Authors: Tetsuya Okajima, Yoko Nakamura, Makoto Uchikawa, David B Haslam, Shinichiro Numata, Keiko Furukawa, Takeshi Urano, Koichi FurukawaAbstract:By using a eukaryocytic cell expression cloning system, we have isolated cDNAs of the globoside synthase (b1,3-N-acetylgalactosaminyltransferase) gene. Mouse fibroblast L cells transfected with SV40 large T antigen and previously cloned Gb3/CD77 synthase cDNAs were co-transfected with a cDNA library prepared from mRNA from human kidney together with Forssman synthase cDNA, and Forssman antigen-positive cells were panned using an anti-Forssman monoclonal antibody. The isolated cDNAs contained a single open reading frame predicting a type II membrane protein with 351 amino acids. Surprisingly, the cDNA clones turned out to be identical with previously reported b3Gal-T3, which had been cloned by sequence homology with other galactosyltransferases. Substrate specificity analysis with extracts from cDNA-transfected L cells confirmed that the gene product was actually b1,3-N-acetylgalactosaminyltransferase that specifically catalyzes the transfer of N-acetylgalactosamine onto globotriaosylceramide. Results of TLC immunostaining of neutral glycolipids from the cDNA-transfected cells also supported the identity of the newly synthesized component as globoside. The results show that glycosyltransferases apparently belonging to a single glycosyltransferase family do not necessarily catalyze reactions utilizing the same acceptor or even the same sugar donor. The globoside synthase gene was expressed in many tissues, such as heart, brain, testis, etc. We propose the designation b3GalNAc-T1 for the cloned globoside synthase gene.
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expression cloning of human globoside synthase cdnas identification of β3gal t3 as udp n acetylgalactosamine globotriaosylceramide β1 3 n acetylgalactosaminyltransferase
Journal of Biological Chemistry, 2000Co-Authors: Tetsuya Okajima, Yoko Nakamura, Makoto Uchikawa, David B Haslam, Shinichiro Numata, Keiko Furukawa, Takeshi Urano, Koichi FurukawaAbstract:Next Section Abstract By using a eukaryocytic cell expression cloning system, we have isolated cDNAs of the globoside synthase (β1,3-N-acetylgalactosaminyltransferase) gene. Mouse fibroblast L cells transfected with SV40 large T antigen and previously cloned Gb3/CD77 synthase cDNAs were co-transfected with a cDNA library prepared from mRNA from human kidney together with Forssman synthase cDNA, and Forssman antigen-positive cells were panned using an anti-Forssman monoclonal antibody. The isolated cDNAs contained a single open reading frame predicting a type II membrane protein with 351 amino acids. Surprisingly, the cDNA clones turned out to be identical with previously reported β3Gal-T3, which had been cloned by sequence homology with other galactosyltransferases. Substrate specificity analysis with extracts from cDNA-transfected L cells confirmed that the gene product was actually β1,3-N-acetylgalactosaminyltransferase that specifically catalyzes the transfer of N-acetylgalactosamine onto globotriaosylceramide. Results of TLC immunostaining of neutral glycolipids from the cDNA-transfected cells also supported the identity of the newly synthesized component as globoside. The results show that glycosyltransferases apparently belonging to a single glycosyltransferase family do not necessarily catalyze reactions utilizing the same acceptor or even the same sugar donor. The globoside synthase gene was expressed in many tissues, such as heart, brain, testis, etc. We propose the designation β3GalNAc-T1 for the cloned globoside synthase gene.
Takeshi Urano - One of the best experts on this subject based on the ideXlab platform.
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Expression Cloning of Human Globoside Synthase cDNAs
2020Co-Authors: Tetsuya Okajima, Yoko Nakamura, Makoto Uchikawa, David B Haslam, Shinichiro Numata, Keiko Furukawa, Takeshi Urano, Koichi FurukawaAbstract:By using a eukaryocytic cell expression cloning system, we have isolated cDNAs of the globoside synthase (b1,3-N-acetylgalactosaminyltransferase) gene. Mouse fibroblast L cells transfected with SV40 large T antigen and previously cloned Gb3/CD77 synthase cDNAs were co-transfected with a cDNA library prepared from mRNA from human kidney together with Forssman synthase cDNA, and Forssman antigen-positive cells were panned using an anti-Forssman monoclonal antibody. The isolated cDNAs contained a single open reading frame predicting a type II membrane protein with 351 amino acids. Surprisingly, the cDNA clones turned out to be identical with previously reported b3Gal-T3, which had been cloned by sequence homology with other galactosyltransferases. Substrate specificity analysis with extracts from cDNA-transfected L cells confirmed that the gene product was actually b1,3-N-acetylgalactosaminyltransferase that specifically catalyzes the transfer of N-acetylgalactosamine onto globotriaosylceramide. Results of TLC immunostaining of neutral glycolipids from the cDNA-transfected cells also supported the identity of the newly synthesized component as globoside. The results show that glycosyltransferases apparently belonging to a single glycosyltransferase family do not necessarily catalyze reactions utilizing the same acceptor or even the same sugar donor. The globoside synthase gene was expressed in many tissues, such as heart, brain, testis, etc. We propose the designation b3GalNAc-T1 for the cloned globoside synthase gene.
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expression cloning of human globoside synthase cdnas identification of β3gal t3 as udp n acetylgalactosamine globotriaosylceramide β1 3 n acetylgalactosaminyltransferase
Journal of Biological Chemistry, 2000Co-Authors: Tetsuya Okajima, Yoko Nakamura, Makoto Uchikawa, David B Haslam, Shinichiro Numata, Keiko Furukawa, Takeshi Urano, Koichi FurukawaAbstract:Next Section Abstract By using a eukaryocytic cell expression cloning system, we have isolated cDNAs of the globoside synthase (β1,3-N-acetylgalactosaminyltransferase) gene. Mouse fibroblast L cells transfected with SV40 large T antigen and previously cloned Gb3/CD77 synthase cDNAs were co-transfected with a cDNA library prepared from mRNA from human kidney together with Forssman synthase cDNA, and Forssman antigen-positive cells were panned using an anti-Forssman monoclonal antibody. The isolated cDNAs contained a single open reading frame predicting a type II membrane protein with 351 amino acids. Surprisingly, the cDNA clones turned out to be identical with previously reported β3Gal-T3, which had been cloned by sequence homology with other galactosyltransferases. Substrate specificity analysis with extracts from cDNA-transfected L cells confirmed that the gene product was actually β1,3-N-acetylgalactosaminyltransferase that specifically catalyzes the transfer of N-acetylgalactosamine onto globotriaosylceramide. Results of TLC immunostaining of neutral glycolipids from the cDNA-transfected cells also supported the identity of the newly synthesized component as globoside. The results show that glycosyltransferases apparently belonging to a single glycosyltransferase family do not necessarily catalyze reactions utilizing the same acceptor or even the same sugar donor. The globoside synthase gene was expressed in many tissues, such as heart, brain, testis, etc. We propose the designation β3GalNAc-T1 for the cloned globoside synthase gene.