Epithelial RAC1-dependent cytoskeleton dynamics controls cell mechanics, cell shedding and barrier integrity in intestinal inflammation

Martínez-Sánchez, Luz del Carmen, Ngo, Phuong Anh, Pradhan, Rashmita, Becker, Lukas-Sebastian, Boehringer, David, Soteriou, Despina, Kubankova, Marketa, Schweitzer, Christine, Koch, Tatyana, Thonn, Veronika, Erkert, Lena, Stolzer, Iris, Günther, Claudia, Becker, Christoph, Weigmann, Benno, Klewer, Monika, Daniel, Christoph, Amann, Kerstin, Tenzer, Stefan, Atreya, Raja, Bergo, Martin, Brakebusch, Cord, Watson, Alastair J. M., Guck, Jochen, Fabry, Ben, Atreya, Imke, Neurath, Markus F. and López-Posadas, Rocío (2022) Epithelial RAC1-dependent cytoskeleton dynamics controls cell mechanics, cell shedding and barrier integrity in intestinal inflammation. Gut. ISSN 0017-5749

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Abstract

Objective: Increased apoptotic shedding has been linked to intestinal barrier dysfunction and development of inflammatory bowel diseases (IBD). In contrast, physiological cell shedding allows the renewal of the epithelial monolayer without compromising the barrier function. Here, we investigated the role of live cell extrusion in epithelial barrier alterations in IBD. Design: Taking advantage of conditional GGTase and RAC1 knockout mice in intestinal epithelial cells (Pggt1biΔIEC and Rac1iΔIEC mice), intravital microscopy, immunostaining, mechanobiology, organoid techniques and RNA sequencing, we analysed cell shedding alterations within the intestinal epithelium. Moreover, we examined human gut tissue and intestinal organoids from patients with IBD for cell shedding alterations and RAC1 function. Results: Epithelial Pggt1b deletion led to cytoskeleton rearrangement and tight junction redistribution, causing cell overcrowding due to arresting of cell shedding that finally resulted in epithelial leakage and spontaneous mucosal inflammation in the small and to a lesser extent in the large intestine. Both in vivo and in vitro studies (knockout mice, organoids) identified RAC1 as a GGTase target critically involved in prenylation-dependent cytoskeleton dynamics, cell mechanics and epithelial cell shedding. Moreover, inflamed areas of gut tissue from patients with IBD exhibited funnel-like structures, signs of arrested cell shedding and impaired RAC1 function. RAC1 inhibition in human intestinal organoids caused actin alterations compatible with arresting of cell shedding. Conclusion: Impaired epithelial RAC1 function causes cell overcrowding and epithelial leakage thus inducing chronic intestinal inflammation. Epithelial RAC1 emerges as key regulator of cytoskeletal dynamics, cell mechanics and intestinal cell shedding. Modulation of RAC1 might be exploited for restoration of epithelial integrity in the gut of patients with IBD.

Item Type: Article
Uncontrolled Keywords: sdg 3 - good health and well-being ,/dk/atira/pure/sustainabledevelopmentgoals/good_health_and_well_being
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
Depositing User: LivePure Connector
Date Deposited: 10 Mar 2022 10:30
Last Modified: 26 Apr 2022 15:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/83973
DOI: 10.1136/gutjnl-2021-325520

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