Graft-versus-host disease propagation depends on increased intestinal epithelial tight junction permeability
Sam C. Nalle, … , Peter A. Savage, Jerrold R. Turner
Sam C. Nalle, … , Peter A. Savage, Jerrold R. Turner
Published January 22, 2019
Citation Information: J Clin Invest. 2019;129(2):902-914. https://doi.org/10.1172/JCI98554.
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Research Article Gastroenterology Oncology

Graft-versus-host disease propagation depends on increased intestinal epithelial tight junction permeability

Abstract

Graft-versus-host disease (GVHD) is a complication of hematopoietic stem cell transplantation (HSCT) that affects multiple organs. GVHD-associated intestinal damage can be separated into two distinct phases, initiation and propagation, which correspond to conditioning-induced damage and effector T cell activation and infiltration, respectively. Substantial evidence indicates that intestinal damage induced by pretransplant conditioning is a key driver of GVHD initiation. Here, we aimed to determine the impact of dysregulated intestinal permeability on the subsequent GVHD propagation phase. The initiation phase of GVHD was unchanged in mice lacking long MLCK (MLCK210), an established regulator of epithelial tight junction permeability. However, MLCK210-deficient mice were protected from sustained barrier loss and exhibited limited GVHD propagation, as indicated by reduced histopathology, fewer CD8+ effector T cells in the gut, and improved overall survival. Consistent with these findings, intestinal epithelial MLCK210 expression and enzymatic activity were similarly increased in human and mouse GVHD biopsies. Intestinal epithelial barrier loss mediated by MLCK210 is therefore a key driver of the GVHD propagation. These data suggest that inhibition of MLCK210-dependent barrier regulation may be an effective approach to limiting GVHD progression.

Authors

Sam C. Nalle, Li Zuo, Ma. Lora Drizella M. Ong, Gurminder Singh, Alicia M. Worthylake, Wangsun Choi, Mario Cabrero Manresa, Anna P. Southworth, Karen L. Edelblum, Gregory J. Baker, Nora E. Joseph, Peter A. Savage, Jerrold R. Turner

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Figure 5

GVHD severity is modulated by intestinal epithelial MLCK210.

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GVHD severity is modulated by intestinal epithelial MLCK210. B6 recipien...
B6 recipients of the indicated genotypes were lethally irradiated, followed by a 129 BMT. (A) Relative weight and (B) disease activity scores (n = 6–9/group). *P < 0.05, ANOVA with Bonferroni’s correction vs. all other conditions. (C) Survival (n = 8–15/group). *P < 0.05, Kaplan-Meier log-rank test, MLCK–/– compared with all other groups. (D) Sections of jejunum were immunostained for CD8 (green) and granzyme B (red) 35 days after BMT. Representative images are shown. Arrowheads indicate colocalization. Scale bar: 20 μm. Each point represents an individual mouse. **P < 0.01, ANOVA with Bonferroni’s correction for MLCK210-KO mice vs. all other conditions (except syngeneic BMT) on d35. (E) Histopathology of jejunum (arrowheads denote apoptotic epithelial cells), liver (arrowheads denote lymphocytes infiltrating biliary epithelium), and skin (arrowheads denote apoptotic squamous cells, asterisks indicate preserved pilosebaceous units) on d35. Scale bars: intestine, 100 μm, 20 μm; liver, 300 μm, 50 μm; skin, 300 μm. (F) Total pathology scores (sum of jejunum, liver, and skin scores) 35 days after BMT. Each point represents an individual mouse. **P < 0.01, ANOVA with Bonferroni’s correction (vs. all other conditions). (G) Gross photos of 2 mice/group 35 days after BMT. Arrowheads point to hair loss and skin ulcers. Scale bar: 1 cm. (H) Correlation between intestinal permeability to fluorescein at 2 weeks after BMT and GVHD severity 5 weeks after BMT. Each point represents an individual mouse. Colors correspond to those for each condition shown in F. r = 0.75, P < 0.01 by Pearson’s correlation coefficient and degrees of freedom.