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Vogel GF, Janecke AR, Krainer IM, Gutleben K, Witting B, Mitton SG, Mansour S, Ballauff A, Roland JT, Engevik AC, Cutz E, Müller T, Goldenring JR, Huber LA, Hess MW. Abnormal Rab11-Rab8-vesicles cluster in enterocytes of patients with microvillus inclusion disease. Traffic 2017; 18:453-464. [PMID: 28407399 DOI: 10.1111/tra.12486] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/05/2017] [Accepted: 04/05/2017] [Indexed: 12/14/2022]
Abstract
Microvillus inclusion disease (MVID) is a congenital enteropathy characterized by accumulation of vesiculo-tubular endomembranes in the subapical cytoplasm of enterocytes, historically termed "secretory granules." However, neither their identity nor pathophysiological significance is well defined. Using immunoelectron microscopy and tomography, we studied biopsies from MVID patients (3× Myosin 5b mutations and 1× Syntaxin3 mutation) and compared them to controls and genome-edited CaCo2 cell models, harboring relevant mutations. Duodenal biopsies from 2 patients with novel Myosin 5b mutations and typical clinical symptoms showed unusual ultrastructural phenotypes: aberrant subapical vesicles and tubules were prominent in the enterocytes, though other histological hallmarks of MVID were almost absent (ectopic intra-/intercellular microvilli, brush border atrophy). We identified these enigmatic vesiculo-tubular organelles as Rab11-Rab8-positive recycling compartments of altered size, shape and location harboring the apical SNARE Syntaxin3, apical transporters sodium-hydrogen exchanger 3 (NHE3) and cystic fibrosis transmembrane conductance regulator. Our data strongly indicate that in MVID disrupted trafficking between cargo vesicles and the apical plasma membrane is the primary cause of a defect of epithelial polarity and subsequent facultative loss of brush border integrity, leading to malabsorption. Furthermore, they support the notion that mislocalization of transporters, such as NHE3 substantially contributes to the reported sodium loss diarrhea.
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Affiliation(s)
- Georg F Vogel
- Division of Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria.,Division of Cell Biology, Medical University of Innsbruck, Innsbruck, Austria.,Department of Paediatrics I, Medical University of Innsbruck, Innsbruck, Austria
| | - Andreas R Janecke
- Department of Paediatrics I, Medical University of Innsbruck, Innsbruck, Austria
| | - Iris M Krainer
- Division of Cell Biology, Medical University of Innsbruck, Innsbruck, Austria.,Department of Paediatrics I, Medical University of Innsbruck, Innsbruck, Austria
| | - Karin Gutleben
- Division of Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria
| | - Barbara Witting
- Division of Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Sahar Mansour
- Human Genetics Research Center, St. George's University of London, London, UK
| | | | - Joseph T Roland
- Section of Surgical Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee.,Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, Tennessee.,Departments of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Amy C Engevik
- Section of Surgical Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee.,Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, Tennessee.,Departments of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Ernest Cutz
- Division of Pathology, Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Canada
| | - Thomas Müller
- Department of Paediatrics I, Medical University of Innsbruck, Innsbruck, Austria
| | - James R Goldenring
- Section of Surgical Sciences, Vanderbilt University School of Medicine, Nashville, Tennessee.,Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, Tennessee.,Departments of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Lukas A Huber
- Division of Cell Biology, Medical University of Innsbruck, Innsbruck, Austria
| | - Michael W Hess
- Division of Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria
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Kravtsov DV, Ahsan MK, Kumari V, van Ijzendoorn SCD, Reyes-Mugica M, Kumar A, Gujral T, Dudeja PK, Ameen NA. Identification of intestinal ion transport defects in microvillus inclusion disease. Am J Physiol Gastrointest Liver Physiol 2016; 311:G142-55. [PMID: 27229121 PMCID: PMC4967175 DOI: 10.1152/ajpgi.00041.2016] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 05/08/2016] [Indexed: 01/31/2023]
Abstract
Loss of function mutations in the actin motor myosin Vb (Myo5b) lead to microvillus inclusion disease (MVID) and death in newborns and children. MVID results in secretory diarrhea, brush border (BB) defects, villus atrophy, and microvillus inclusions (MVIs) in enterocytes. How loss of Myo5b results in increased stool loss of chloride (Cl(-)) and sodium (Na(+)) is unknown. The present study used Myo5b loss-of-function human MVID intestine, polarized intestinal cell models of secretory crypt (T84) and villus resembling (CaCo2BBe, C2BBe) enterocytes lacking Myo5b in conjunction with immunofluorescence confocal stimulated emission depletion (gSTED) imaging, immunohistochemical staining, transmission electron microscopy, shRNA silencing, immunoblots, and electrophysiological approaches to examine the distribution, expression, and function of the major BB ion transporters NHE3 (Na(+)), CFTR (Cl(-)), and SLC26A3 (DRA) (Cl(-)/HCO3 (-)) that control intestinal fluid transport. We hypothesized that enterocyte maturation defects lead villus atrophy with immature secretory cryptlike enterocytes in the MVID epithelium. We investigated the role of Myo5b in enterocyte maturation. NHE3 and DRA localization and function were markedly reduced on the BB membrane of human MVID enterocytes and Myo5bKD C2BBe cells, while CFTR localization was preserved. Forskolin-stimulated CFTR ion transport in Myo5bKD T84 cells resembled that of control. Loss of Myo5b led to YAP1 nuclear retention, retarded enterocyte maturation, and a cryptlike phenotype. We conclude that preservation of functional CFTR in immature enterocytes, reduced functional expression of NHE3, and DRA contribute to Cl(-) and Na(+) stool loss in MVID diarrhea.
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Affiliation(s)
- Dmitri V. Kravtsov
- 1Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, New Haven, Connecticut;
| | - Md Kaimul Ahsan
- 1Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, New Haven, Connecticut;
| | - Vandana Kumari
- 1Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, New Haven, Connecticut;
| | - Sven C. D. van Ijzendoorn
- 2Department of Cell Biology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands;
| | | | - Anoop Kumar
- 4Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Tarunmeet Gujral
- 4Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Pradeep K. Dudeja
- 4Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois and Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois; and
| | - Nadia A. Ameen
- 1Department of Pediatrics/Gastroenterology and Hepatology, Yale School of Medicine, New Haven, Connecticut; ,5Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
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