Annexin A1, formyl peptide receptor, and NOX1 orchestrate epithelial repair
Giovanna Leoni, … , Andrew S. Neish, Asma Nusrat
Giovanna Leoni, … , Andrew S. Neish, Asma Nusrat
Published December 17, 2012
Citation Information: J Clin Invest. 2013;123(1):443-454. https://doi.org/10.1172/JCI65831.
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Research Article Gastroenterology

Annexin A1, formyl peptide receptor, and NOX1 orchestrate epithelial repair

Abstract

N-formyl peptide receptors (FPRs) are critical regulators of host defense in phagocytes and are also expressed in epithelia. FPR signaling and function have been extensively studied in phagocytes, yet their functional biology in epithelia is poorly understood. We describe a novel intestinal epithelial FPR signaling pathway that is activated by an endogenous FPR ligand, annexin A1 (ANXA1), and its cleavage product Ac2-26, which mediate activation of ROS by an epithelial NADPH oxidase, NOX1. We show that epithelial cell migration was regulated by this signaling cascade through oxidative inactivation of the regulatory phosphatases PTEN and PTP-PEST, with consequent activation of focal adhesion kinase (FAK) and paxillin. In vivo studies using intestinal epithelial specific Nox1–/–IEC and AnxA1–/– mice demonstrated defects in intestinal mucosal wound repair, while systemic administration of ANXA1 promoted wound recovery in a NOX1-dependent fashion. Additionally, increased ANXA1 expression was observed in the intestinal epithelium and infiltrating leukocytes in the mucosa of ulcerative colitis patients compared with normal intestinal mucosa. Our findings delineate a novel epithelial FPR1/NOX1-dependent redox signaling pathway that promotes mucosal wound repair.

Authors

Giovanna Leoni, Ashfaqul Alam, Philipp-Alexander Neumann, J. David Lambeth, Guangjie Cheng, James McCoy, Roland S. Hilgarth, Kousik Kundu, Niren Murthy, Dennis Kusters, Chris Reutelingsperger, Mauro Perretti, Charles A. Parkos, Andrew S. Neish, Asma Nusrat

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Figure 1

ANXA1 regulates wound healing via FPR1 signaling in IECs and stimulates phosphorylation of focal adhesion proteins (FAK and Pax).

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ANXA1 regulates wound healing via FPR1 signaling in IECs and stimulates ...
(A) SK-CO15 monolayers were subjected to scratch wound assay in the presence of Ac2-26 peptide (3 μM). Wound widths were determined at 0 and 24 hours. Photomicrograph shows representative results for control (Ctl) and Ac2-26–treated cells. Scale bar: 200 μm. (B) SK-CO15 cells were also incubated with Ac2-26 and CsH (1 μM) or WRW4 (10 μM). The ANXA1 cleavage product Ac2-26 alone significantly enhanced wound closure (*P < 0.0001). The increase in wound closure was inhibited in the presence of CsH (#P < 0.0001) but not WRW4. The experiment was repeated 3 times, and results of 1 representative experiment done with 5 parallel samples are shown. (C) Endoscopic images of colonic mucosal wounds in mice (AnxA1–/– and control BALB/c) at days 2 and 4 after injury. Quantification of wound repair is shown in the graph (mean ± SEM, *P = 0.023, n = 11 mice/group). (D) SK-CO15 cells were plated on ECL gel, and non-adherent cells were removed by washing at 1 hour after plating. Adhesion increased within 15 minutes of Ac2-26 exposure compared with non-stimulated cells (*P < 0.0001). (E) Immunoblot of SK-CO15 cells revealed a significant increase in Pax phosphorylation (Y118, 2.4-fold) and FAK phosphorylation (Y861, 2.2-fold) in cells stimulated with Ac2-26 for 15 minutes compared with unstimulated cells (0.1% DMSO). Normalized signal intensity is indicated above the blots. (F) Laser confocal micrographs of Pax p-Y118 (white) or FAK p-Y861 (white) and F-actin (red) in migrating SK-CO15 cells with or without Ac2-26 (3 μM) for 15 minutes. Photomicrographs are representative of 3 independent experiments done in triplicate. Scale bars: 10 μm.