Annexin A1–containing extracellular vesicles and polymeric nanoparticles promote epithelial wound repair
Giovanna Leoni, … , Andrew S. Neish, Asma Nusrat
Giovanna Leoni, … , Andrew S. Neish, Asma Nusrat
Published February 9, 2015
Citation Information: J Clin Invest. 2015;125(3):1215-1227. https://doi.org/10.1172/JCI76693.
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Research Article Gastroenterology

Annexin A1–containing extracellular vesicles and polymeric nanoparticles promote epithelial wound repair

Abstract

Epithelial restitution is an essential process that is required to repair barrier function at mucosal surfaces following injury. Prolonged breaches in epithelial barrier function result in inflammation and further damage; therefore, a better understanding of the epithelial restitution process has potential for improving the development of therapeutics. In this work, we demonstrate that endogenous annexin A1 (ANXA1) is released as a component of extracellular vesicles (EVs) derived from intestinal epithelial cells, and these ANXA1-containing EVs activate wound repair circuits. Compared with healthy controls, patients with active inflammatory bowel disease had elevated levels of secreted ANXA1-containing EVs in sera, indicating that ANXA1-containing EVs are systemically distributed in response to the inflammatory process and could potentially serve as a biomarker of intestinal mucosal inflammation. Local intestinal delivery of an exogenous ANXA1 mimetic peptide (Ac2-26) encapsulated within targeted polymeric nanoparticles (Ac2-26 Col IV NPs) accelerated healing of murine colonic wounds after biopsy-induced injury. Moreover, one-time systemic administration of Ac2-26 Col IV NPs accelerated recovery following experimentally induced colitis. Together, our results suggest that local delivery of proresolving peptides encapsulated within nanoparticles may represent a potential therapeutic strategy for clinical situations characterized by chronic mucosal injury, such as is seen in patients with IBD.

Authors

Giovanna Leoni, Philipp-Alexander Neumann, Nazila Kamaly, Miguel Quiros, Hikaru Nishio, Hefin R. Jones, Ronen Sumagin, Roland S. Hilgarth, Ashfaqul Alam, Gabrielle Fredman, Ioannis Argyris, Emile Rijcken, Dennis Kusters, Chris Reutelingsperger, Mauro Perretti, Charles A. Parkos, Omid C. Farokhzad, Andrew S. Neish, Asma Nusrat

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Figure 2

EVs containing ANXA1 regulate epithelial wound healing.

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EVs containing ANXA1 regulate epithelial wound healing. (A) Representati...
(A) Representative (of n = 5) en face image of migrating IECs after 24 hours of interaction with labeled EVs (CFSE, 10 μmol/l; Molecular Probes). The boxed area (original magnification, ×40) is shown at high magnification in the image below (original magnification, ×100). Scale bar: 10 μm. (B and C) Scratch wound healing assay using IEC monolayers. EVs and hrANXA1 were added to wounded IECs alone and in the presence of FPR1 antagonist, CsH (1 μM); FPR2/ALX antagonist, WRW4 (10 μM); and other conditions, as indicated. Wound widths were determined at time 0 and 24 hours (n = 5, mean ± SEM) (original magnification, ×10). (D) Scratch wound healing assay using IEC monolayers. EVs were added to wounded IECs alone and in the presence of mouse monoclonal ANXA1 inhibitory antibody (250 μg/ml) or control IgG antibody (250 μg/ml). The experiments in C and D were repeated 3 times, and results of one representative experiment performed with 5 parallel samples are shown (mean ± SEM). ***P < 0.0001 compared with control; ###P < 0.0001 compared with EVs. (E and F) IECs were incubated with EVs for 15 minutes, and ROS generation was detected by confocal microscopy using the fluorescent Hydro-Cy3 dye (15 μM). Scale bar: 40 μm. Summarized data for Hydro-Cy3 fluorescence intensity are presented in the graph (mean ± SEM, *P = 0.0002 vs. control, n = 3). Confocal micrographs are representative of 3 independent experiments. All the results in this figure are representative of at least 3 independent experiments. Statistical comparisons were performed by ANOVA with Tukey’s multiple comparison post-test for C and D and 2-tailed Student’s t test for F. RFU, relative fluorescent units.