IFN-γ drives inflammatory bowel disease pathogenesis through VE-cadherin–directed vascular barrier disruption
Victoria Langer, … , Nathalie Britzen-Laurent, Michael Stürzl
Victoria Langer, … , Nathalie Britzen-Laurent, Michael Stürzl
Published September 30, 2019
Citation Information: J Clin Invest. 2019;129(11):4691-4707. https://doi.org/10.1172/JCI124884.
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Research Article Gastroenterology Vascular biology

IFN-γ drives inflammatory bowel disease pathogenesis through VE-cadherin–directed vascular barrier disruption

Abstract

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder with rising incidence. Diseased tissues are heavily vascularized. Surprisingly, the pathogenic impact of the vasculature in IBD and the underlying regulatory mechanisms remain largely unknown. IFN-γ is a major cytokine in IBD pathogenesis, but in the context of the disease, it is almost exclusively its immune-modulatory and epithelial cell–directed functions that have been considered. Recent studies by our group demonstrated that IFN-γ also exerts potent effects on blood vessels. Based on these considerations, we analyzed the vessel-directed pathogenic functions of IFN-γ and found that it drives IBD pathogenesis through vascular barrier disruption. Specifically, we show that inhibition of the IFN-γ response in vessels by endothelial-specific knockout of IFN-γ receptor 2 ameliorates experimentally induced colitis in mice. IFN-γ acts pathogenic by causing a breakdown of the vascular barrier through disruption of the adherens junction protein VE-cadherin. Notably, intestinal vascular barrier dysfunction was also confirmed in human IBD patients, supporting the clinical relevance of our findings. Treatment with imatinib restored VE-cadherin/adherens junctions, inhibited vascular permeability, and significantly reduced colonic inflammation in experimental colitis. Our findings inaugurate the pathogenic impact of IFN-γ–mediated intestinal vessel activation in IBD and open new avenues for vascular-directed treatment of this disease.

Authors

Victoria Langer, Eugenia Vivi, Daniela Regensburger, Thomas H. Winkler, Maximilian J. Waldner, Timo Rath, Benjamin Schmid, Lisa Skottke, Somin Lee, Noo Li Jeon, Thomas Wohlfahrt, Viktoria Kramer, Philipp Tripal, Michael Schumann, Stephan Kersting, Claudia Handtrack, Carol I. Geppert, Karina Suchowski, Ralf H. Adams, Christoph Becker, Andreas Ramming, Elisabeth Naschberger, Nathalie Britzen-Laurent, Michael Stürzl

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Figure 3

IFN-γ exerts angiostatic effects in vitro, ex vivo, and in vivo.

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IFN-γ exerts angiostatic effects in vitro, ex vivo, and in vivo. (A) In ...
(A) In vitro angiogenesis on a 3D microfluidic chip using HUVEC and fibroblast cocultures. Representative pictures are shown. IFN-γ significantly reduced angiogenic sprout length and thickness. Scale bar: 300 μm. Quantification included control (n = 9) and IFN-γ–treated (100 U/mL) chips (n = 6) with 15 sprouts analyzed per chip. (B) Metatarsals of 18.5-day-old mouse embryos after 10 days of cultivation. Ex vivo vessel outgrowth was visualized by immunofluorescence staining (CD31, green). Vessel outgrowth stimulated by VEGF-A (100 ng/mL) was completely inhibited by IFN-γ (100 U/mL) in control but not in Ifngr2ΔEC mice. One representative picture of 5 experiments is shown. Scale bar: 500 μm. (C) Representative images of colon tissue from control and Ifngr2EC mice with DSS-colitis double-stained for CD31 (green) and Ki-67 (pink). Counterstaining was performed with DRAQ5 (blue). The arrow indicates an example of a nonproliferating vessel, whereas the arrowhead points to a proliferating vessel. Scale bar: 50 μm. Vessel number (CD31+ with lumen) was counted in 10 regions per section (n = 9 control mice; n = 10 Ifngr2ΔEC mice). Ki-67+ vessels were counted as angiogenic vessels, and 162 vessels per group were analyzed in total (n = 9 control mice; n = 9 Ifngr2ΔEC mice). Quantification included pooled results from 2 independent experiments (right panels). Data are expressed as box-and-whisker plots (horizontal bars, median; box borders, 25th and 75th percentiles; whiskers, minimum and maximum values) (A) or as means ± SD (C). Two-tailed, unpaired Student’s t test (A, length; C, vessel number) and Mann-Whitney U test (A, thickness; C, vessel proliferation) were used to determine statistical significance (**P < 0.01, ***P < 0.001, ****P < 0.0001).