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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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 6

EGFR signaling is critical for macrophage activation and function.

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EGFR signaling is critical for macrophage activation and function. (A) m...
(A) mRNA levels of the M1 activation markers Nos2, Tnfa, and Il1b were assessed by qRT-PCR in WT BMmacs 24 hours p.i. with H. pylori PMSS1 ± 10 μM gefitinib. n = 3 biological replicates. ***P < 0.001. (B) mRNA levels of the M1 activation markers Nos2, Tnfa, and Il1b were assessed by qRT-PCR in Egfrfl/fl and EgfrΔmye BMmacs 24 hours p.i. with H. pylori PMSS1. n = 3 mice per genotype. ***P < 0.001. (C) Representative Western blot of NOS2 in RAW 264.7 cells 24 hours p.i. with H. pylori PMSS1 ± 150 nM AG1478 (AG) or 10 μM gefitinib (Gef). UT, untreated. n = 3 biological replicates. (D) Representative Western blot of NOS2 in WT BMmacs 24 hours p.i. with H. pylori PMSS1, SS1, or 7.13 ± 10 μM gefitinib. n = 3 biological replicates. (E) Measurement of NO2– from RAW 264.7 cell supernatants 24 hours p.i. with H. pylori PMSS1, SS1, or 7.13 ± 150 nM AG1478 or 300 nM PD153035. n = 5 biological replicates. †P < 0.05 versus PMSS1 alone; *P < 0.05 and **P < 0.01 versus SS1 alone; §P < 0.05 versus 7.13 alone. (F) Measurement of NO2– from Egfrfl/fl and EgfrΔmye BMmac supernatants 24 hours p.i. with H. pylori PMSS1. n = 3 mice per genotype. **P < 0.01. (G) Measurement of IL-1β in Egfrfl/fl and EgfrΔmye BMmac supernatants 24 hours p.i. with H. pylori PMSS1. n = 3 mice per genotype. **P < 0.01. Statistical significance in all panels was calculated by 1-way ANOVA with Newman-Keuls post test.