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An Intravital Microscopy-Based Approach to Assess Intestinal Permeability and Epithelial Cell Shedding Performance
Published on: December 3, 2020
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Intestinal epithelial cell-specific RARα depletion results in aberrant epithelial cell homeostasis and underdeveloped
H B Jijon1,2, L Suarez-Lopez3, O E Diaz4
1Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts, USA.
Mucosal Immunology
|November 16, 2017
Summary
Epithelial cell-intrinsic retinoic acid (RA) signaling, mediated by RA receptor alpha (RARα), is vital for intestinal immune system development. Its absence disrupts epithelial cell differentiation and impairs immune responses.
Area of Science:
- Immunology
- Gastroenterology
- Developmental Biology
Background:
- Retinoic acid (RA), a vitamin A metabolite, is essential for intestinal homeostasis and immune cell function.
- The role of RA signaling in intestinal epithelial cells (IECs) and its impact on immune regulation remains largely unexamined.
Purpose of the Study:
- To investigate the role of RA receptor alpha (RARα) signaling within IECs for intestinal immune system development.
- To elucidate the mechanisms by which RARα signaling influences epithelial cell differentiation and immune cell populations.
Main Methods:
- Utilized a model lacking RARα signaling specifically in IECs.
- Analyzed epithelial cell lineage specification, including goblet and Paneth cell differentiation.
- Assessed intestinal immune system development, lymphoid follicle formation, and mononuclear phagocyte populations.
- Evaluated host defense against Citrobacter rodentium infection.
Main Results:
- Loss of IEC RARα signaling led to deregulated epithelial lineage specification, increasing goblet and Paneth cells.
- RARα deficiency resulted in increased KLF4+ goblet cell precursors, while RA inhibited klf4 expression and goblet cell differentiation in zebrafish.
- These epithelial changes were linked to increased Reg3g, reduced bacterial load, and an underdeveloped intestinal immune system, characterized by absent lymphoid follicles and gut resident mononuclear phagocytes.
- The compromised immune system exhibited impaired clearance of Citrobacter rodentium infection.
Conclusions:
- Epithelial cell-intrinsic RARα signaling is critical for the overall development of the intestinal immune system.
- RARα signaling in IECs regulates epithelial cell differentiation and is essential for establishing a functional intestinal immune environment.
- These findings highlight a novel mechanism linking nutrient metabolism, epithelial development, and immune system maturation in the gut.
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