EGFR regulates macrophage activation and function in bacterial infection
Dana M. Hardbower, … , M. Blanca Piazuelo, Keith T. Wilson
Dana M. Hardbower, … , M. Blanca Piazuelo, Keith T. Wilson
Published August 2, 2016
Citation Information: J Clin Invest. 2016;126(9):3296-3312. https://doi.org/10.1172/JCI83585.
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Research Article Gastroenterology

EGFR regulates macrophage activation and function in bacterial infection

Abstract

EGFR signaling regulates macrophage function, but its role in bacterial infection has not been investigated. Here, we assessed the role of macrophage EGFR signaling during infection with Helicobacter pylori, a bacterial pathogen that causes persistent inflammation and gastric cancer. EGFR was phosphorylated in murine and human macrophages during H. pylori infection. In human gastric tissues, elevated levels of phosphorylated EGFR were observed throughout the histologic cascade from gastritis to carcinoma. Deleting Egfr in myeloid cells attenuated gastritis and increased H. pylori burden in infected mice. EGFR deficiency also led to a global defect in macrophage activation that was associated with decreased cytokine, chemokine, and NO production. We observed similar alterations in macrophage activation and disease phenotype in the Citrobacter rodentium model of murine infectious colitis. Mechanistically, EGFR signaling activated NF-κB and MAPK1/3 pathways to induce cytokine production and macrophage activation. Although deletion of Egfr had no effect on DC function, EGFR-deficient macrophages displayed impaired Th1 and Th17 adaptive immune responses to H. pylori, which contributed to decreased chronic inflammation in infected mice. Together, these results indicate that EGFR signaling is central to macrophage function in response to enteric bacterial pathogens and is a potential therapeutic target for infection-induced inflammation and associated carcinogenesis.

Authors

Dana M. Hardbower, Kshipra Singh, Mohammad Asim, Thomas G. Verriere, Danyvid Olivares-Villagómez, Daniel P. Barry, Margaret M. Allaman, M. Kay Washington, Richard M. Peek Jr., M. Blanca Piazuelo, Keith T. Wilson

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Figure 7

EGFR and NF-κB form a critical link in macrophages in response to H. pylori.

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EGFR and NF-κB form a critical link in macrophages in response to H. pyl...
(A) Representative Western blot of MyD88 protein levels in Egfrfl/fl and EgfrΔmye BMmacs 30 minutes p.i. with H. pylori PMSS1. n = 3 biological replicates. (B) Representative Western blots of p-IKBK (also known as p-IKK) and p-NFKBIA (also known as p-IκBα) protein levels in Egfrfl/fl and EgfrΔmye BMmacs 30 and 45 minutes p.i. with H. pylori PMSS1. n = 3 biological replicates. (C) Representative Western blot of cytoplasmic and nuclear fractions of t-RELA (p65) in Egfrfl/fl and EgfrΔmye BMmacs 60 minutes p.i. with H. pylori PMSS1. n = 3 biological replicates. (D) Densitometric analysis of cytoplasmic and nuclear t-RELA. n = 3 biological replicates. **P < 0.01, by 2-tailed Student’s t test. (E) Western blot of cytoplasmic and nuclear fractions of p-RELA (p-p65) in Egfrfl/fl and EgfrΔmye BMmacs 60 minutes p.i. with H. pylori PMSS1. (F) Measurement of luminescence from an NF-κB luciferase reporter in immortalized BMmacs (NGL cells) at the indicated time points p.i. with H. pylori PMSS1 or SS1 ± 10 μM gefitinib. n = 4 biological replicates *P < 0.05 versus PMSS1 alone; §P < 0.05 versus SS1 alone, by 1-way ANOVA with Newman-Keuls post test.