title: An inducible mouse model for microvillus inclusion disease reveals a role for myosin Vb in apical and basolateral trafficking.
abstract: Microvillus inclusion disease (MVID) is a rare intestinal enteropathy with an onset within a few days to months after birth, resulting in persistent watery diarrhea. Mutations in the myosin Vb gene (MYO5B) have been identified in the majority of MVID patients. However, the exact pathophysiology of MVID still remains unclear. To address the specific role of MYO5B in the intestine, we generated an intestine-specific conditional Myo5b-deficient (Myo5bfl/fl;Vil-CreERT2) mouse model. We analyzed intestinal tissues and cultured organoids of Myo5bfl/fl;Vil-CreERT2 mice by electron microscopy, immunofluorescence, and immunohistochemistry. Our data showed that Myo5bfl/fl;Vil-CreERT2 mice developed severe diarrhea within 4 d after tamoxifen induction. Periodic Acid Schiff and alkaline phosphatase staining revealed subapical accumulation of intracellular vesicles in villus enterocytes. Analysis by electron microscopy confirmed an almost complete absence of apical microvilli, the appearance of microvillus inclusions, and enlarged intercellular spaces in induced Myo5bfl/fl;Vil-CreERT2 intestines. In addition, we determined that MYO5B is involved not only in apical but also basolateral trafficking of proteins. The analysis of the intestine during the early onset of the disease revealed that subapical accumulation of secretory granules precedes occurrence of microvillus inclusions, indicating involvement of MYO5B in early differentiation of epithelial cells. By comparing our data with a novel MVID patient, we conclude that our mouse model completely recapitulates the intestinal phenotype of human MVID. This includes severe diarrhea, loss of microvilli, occurrence of microvillus inclusions, and subapical secretory granules. Thus, loss of MYO5B disturbs both apical and basolateral trafficking of proteins and causes MVID in mice.
authors.affiliation: Division of Paediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Centre (UMC) Utrecht, 3584 EA, Utrecht, The Netherlands;
authors.forename: Kerstin
authors.initials: K
authors.lastname: Schneeberger
authors.affiliation: Division of Cell Biology, Biocenter, Medical University Innsbruck, A-6020 Innsbruck, Austria; Division of Histology and Embryology, Medical University Innsbruck, A-6020 Innsbruck Austria;
authors.forename: Georg F
authors.initials: GF
authors.lastname: Vogel
authors.affiliation: Division of Paediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Centre (UMC) Utrecht, 3584 EA, Utrecht, The Netherlands;
authors.forename: Hans
authors.initials: H
authors.lastname: Teunissen
authors.affiliation: Laboratory of Translational Immunology and Department of Paediatric Pulmonology, Wilhelmina Children's Hospital, UMC Utrecht, 3584 EA, Utrecht, The Netherlands;
authors.forename: Domenique D
authors.initials: DD
authors.lastname: van Ommen
authors.affiliation: Hubrecht Institute for Developmental Biology and Stem Cell Research, Royal Dutch Academy of Sciences and UMC Utrecht, 3584 CT, Utrecht, The Netherlands;
authors.forename: Harry
authors.initials: H
authors.lastname: Begthel
authors.affiliation: Division of Paediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Centre (UMC) Utrecht, 3584 EA, Utrecht, The Netherlands;
authors.forename: Layla
authors.initials: L
authors.lastname: El Bouazzaoui
authors.affiliation: Division of Paediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Centre (UMC) Utrecht, 3584 EA, Utrecht, The Netherlands;
authors.forename: Anke H M
authors.initials: AH
authors.lastname: van Vugt
authors.affiliation: Laboratory of Translational Immunology and Department of Paediatric Pulmonology, Wilhelmina Children's Hospital, UMC Utrecht, 3584 EA, Utrecht, The Netherlands;
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Beekman
authors.affiliation: Department of Cell Biology and The Cell Microscopy Centre, UMC Utrecht, 3584 CX, Utrecht, The Netherlands;
authors.forename: Judith
authors.initials: J
authors.lastname: Klumperman
authors.affiliation: Department of Pediatrics I, Medical University Innsbruck, A-6020 Innsbruck, Austria;
authors.forename: Thomas
authors.initials: T
authors.lastname: Müller
authors.affiliation: Department of Pediatrics I, Medical University Innsbruck, A-6020 Innsbruck, Austria; Division of Human Genetics, Medical University Innsbruck, A-6020 Innsbruck, Austria;
authors.forename: Andreas
authors.initials: A
authors.lastname: Janecke
authors.affiliation: Zentrum für Kinder- und Jugendmedizin, Universitätsklinikum Freiburg, 79106 Freiburg, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Gerner
authors.affiliation: Division of Cell Biology, Biocenter, Medical University Innsbruck, A-6020 Innsbruck, Austria;
authors.forename: Lukas A
authors.initials: LA
authors.lastname: Huber
authors.affiliation: Division of Histology and Embryology, Medical University Innsbruck, A-6020 Innsbruck Austria;
authors.forename: Michael W
authors.initials: MW
authors.lastname: Hess
authors.affiliation: Hubrecht Institute for Developmental Biology and Stem Cell Research, Royal Dutch Academy of Sciences and UMC Utrecht, 3584 CT, Utrecht, The Netherlands; h.clevers@hubrecht.eu s.middendorp@umcutrecht.nl.
authors.forename: Hans
authors.initials: H
authors.lastname: Clevers
authors.affiliation: Hubrecht Institute for Developmental Biology and Stem Cell Research, Royal Dutch Academy of Sciences and UMC Utrecht, 3584 CT, Utrecht, The Netherlands;
authors.forename: Johan H
authors.initials: JH
authors.lastname: van Es
authors.affiliation: Division of Paediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Centre (UMC) Utrecht, 3584 EA, Utrecht, The Netherlands;
authors.forename: Edward E S
authors.initials: EE
authors.lastname: Nieuwenhuis
authors.affiliation: Division of Paediatrics, Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Centre (UMC) Utrecht, 3584 EA, Utrecht, The Netherlands; h.clevers@hubrecht.eu s.middendorp@umcutrecht.nl.
authors.forename: Sabine
authors.initials: S
authors.lastname: Middendorp
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D020895:Enterocytes / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000473:pathology / Q000648:ultrastructure; D008286:Malabsorption Syndromes / Q000139:chemically induced / Q000378:metabolism*; D008297:Male; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D018345:Mice, Knockout; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D008871:Microvilli / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D009081:Mucolipidoses / Q000139:chemically induced / Q000378:metabolism*; D024701:Myosin Type V / Q000235:genetics / Q000378:metabolism*; D009924:Organ Culture Techniques; D021381:Protein Transport / Q000235:genetics / Q000502:physiology; D013629:Tamoxifen
chemical_list: C588269:Myo5B protein, mouse; D013629:Tamoxifen; D024701:Myosin Type V
keywords: epithelila polarity; intestinal enteropathy; microvillus inclusion disease; mouse model; myosin Vb