Rubicon is a critical regulator of immune barrier integrity and limits enteric pathogen infection
6 affiliations
- 1USF Health Neuroscience Institute
- 2Department of Molecular Medicine, Morsani College of Medicine, University of South Florida
- 3Department of Neurosurgery, Brain and Spine, Morsani College of Medicine, University of South Florida
- 4USF Center for Microbiome Research, USF Microbiome Institute, Morsani College of Medicine, University of South Florida
- 5Center of Excellence for Aging and Brain Repair, Morsani College of Medicine, University of South Florida
- 6Department of Medical Engineering – University of South Florida
Abstract
Introduction: Intestinal immune barrier integrity is governed by coordinated epithelial renewal, junctional organization, and vesicular trafficking. Herein, we identify a previously undefined role for the noncanonical autophagy protein Rubicon in the maintence of the intestinal immune barrier. Rubicon-dependent vesicular pathways, including conjugation of ATG8 proteins to single membranes (CASM) function to support vesicle trafficking homeostasis.
Methods: Mice with global deletion of Rubicon (Rubcn ⁻ / ⁻ ) were used to evaluate impact on gut permeability using FITC-dextran, overall intestinal anatomy and histopathology, junction protein homeostasis, and pathogen response.
Results and discussion: Loss of Rubicon led to impaired intestinal barrier function and increased intestinal permeability, supported by a 10-fold increase in circulating FITC-dextran. Rubicon-deficiency was also associated with multiple anatomical changes including elongation of the small and large intestines, shortened small-intestinal villi, epithelial hyperplasia, and lymphoid expansion, amongst others. Mechanistically, Rubicon-deficiency resulted in aberrant trafficking and mislocalization of key junctional proteins including E-cadherin and occludin. Furthermore, metagenomic analysis of the intestinal microbial community revealed broad restructuring of the intestinal microbiota compared to WT animals. Importantly, Rubicon-deficiency hypersensitized mice to enteric pathogen infection. Rubcn ⁻ / ⁻ mice exhibited accelerated and worsened mortality in addition to systemic bacteremia following infection with Salmonella Typhimurium . Bacterial burden was significantly in multiple tissues including mesenteric lymph nodes, spleen, and liver, further supporting failure of the intestinal barrier following loss of Rubicon. Collectively, these findings identify Rubicon as a novel and foundational regulator of IEC vesicular processing, epithelial junctional organization, intestinal barrier function, and host defense beyond established roles in innate immune cells.
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BibTeX
@article{scaffidi2026rubicon,
title = {{Rubicon is a critical regulator of immune barrier integrity and limits enteric pathogen infection}},
author = {Alexis D. Scaffidi and Salvatore J. Scaffidi and Jeremy Carling and Austin Fajfer and Mubashshir Ali and Ryosuke Ono and Addison Hilyard and Rachel E. Buksbaum and Vivek Kumar and Rohit Shukla and Sidharth Mishra and Shalini Jain and Hariom Yadav and Bradlee L. Heckmann},
journal = {Frontiers in Immunology},
year = {2026},
month = oct,
doi = {10.3389/fimmu.2026.1889997},
url = {https://www.frontiersin.org/articles/10.3389/fimmu.2026.1889997/full},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Rubicon is a critical regulator of immune barrier integrity and limits enteric pathogen infection
AU - Alexis D. Scaffidi
AU - Salvatore J. Scaffidi
AU - Jeremy Carling
AU - Austin Fajfer
AU - Mubashshir Ali
AU - Ryosuke Ono
AU - Addison Hilyard
AU - Rachel E. Buksbaum
AU - Vivek Kumar
AU - Rohit Shukla
AU - Sidharth Mishra
AU - Shalini Jain
AU - Hariom Yadav
AU - Bradlee L. Heckmann
PY - 2026
DA - 2026/10/19
JO - Frontiers in Immunology
DO - 10.3389/fimmu.2026.1889997
UR - https://www.frontiersin.org/articles/10.3389/fimmu.2026.1889997/full
AB - Introduction: Intestinal immune barrier integrity is governed by coordinated epithelial renewal, junctional organization, and vesicular trafficking. Herein, we identify a previously undefined role for the noncanonical autophagy protein Rubicon in the maintence of the intestinal immune barrier. Rubicon-dependent vesicular pathways, including conjugation of ATG8 proteins to single membranes (CASM) function to support vesicle trafficking homeostasis. Methods: Mice with global deletion of Rubicon (Rubcn ⁻ / ⁻ ) were used to evaluate impact on gut permeability using FITC-dextran, overall intestinal anatomy and histopathology, junction protein homeostasis, and pathogen response. Results and discussion: Loss of Rubicon led to impaired intestinal barrier function and increased intestinal permeability, supported by a 10-fold increase in circulating FITC-dextran. Rubicon-deficiency was also associated with multiple anatomical changes including elongation of the small and large intestines, shortened small-intestinal villi, epithelial hyperplasia, and lymphoid expansion, amongst others. Mechanistically, Rubicon-deficiency resulted in aberrant trafficking and mislocalization of key junctional proteins including E-cadherin and occludin. Furthermore, metagenomic analysis of the intestinal microbial community revealed broad restructuring of the intestinal microbiota compared to WT animals. Importantly, Rubicon-deficiency hypersensitized mice to enteric pathogen infection. Rubcn ⁻ / ⁻ mice exhibited accelerated and worsened mortality in addition to systemic bacteremia following infection with Salmonella Typhimurium . Bacterial burden was significantly in multiple tissues including mesenteric lymph nodes, spleen, and liver, further supporting failure of the intestinal barrier following loss of Rubicon. Collectively, these findings identify Rubicon as a novel and foundational regulator of IEC vesicular processing, epithelial junctional organization, intestinal barrier function, and host defense beyond established roles in innate immune cells.
SN - 1664-3224
ER -