Department of Breast Cancer Medical Oncology, Key Laboratory of Breast Cancer Prevention and Therapy, Ministry of Education, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Tianjin 300060, P. R. China;
J Immunol. 2014 Feb 1;192(3):1013-23. doi: 10.4049/jimmunol.1300133. Epub 2014 Jan 3.
Macrophages regulate innate immunity to maintain intestinal homeostasis and play pathological roles in intestinal inflammation. Activation of the epidermal growth factor receptor (EGFR) promotes cellular proliferation, differentiation, survival, and wound closure in several cell types. However, the impact of EGFR in macrophages remains unclear. This study was to investigate whether EGFR activation in macrophages regulates cytokine production and intestinal inflammation. We found that EGFR was activated in colonic macrophages in mice with dextran sulfate sodium (DSS)-induced colitis and in patients with ulcerative colitis. DSS-induced acute colitis was ameliorated, and recovery from colitis was promoted in Egfr(fl/fl)LysM-Cre mice with myeloid cell-specific deletion of EGFR, compared with LysM-Cre mice. DSS treatment increased IL-10 and TNF levels during the acute phase of colitis, and increased IL-10 but reduced TNF levels during the recovery phase in Egfr(fl/fl)LysM-Cre mice. An anti-IL-10 neutralizing Ab abolished these effects of macrophage-specific EGFR deletion on DSS-induced colitis in Egfr(fl/fl)LysM-Cre mice. LPS stimulated EGFR activation and inhibition of EGFR kinase activity enhanced LPS-stimulated NF-κB activation in RAW 264.7 macrophages. Furthermore, induction of IL-10 production by EGFR kinase-blocked RAW 264.7 cells, in response to LPS plus IFN-γ, correlated with decreased TNF production. Thus, although selective deletion of EGFR in macrophages leads to increases in both pro- and anti-inflammatory cytokines in response to inflammatory stimuli, the increase in the IL-10 level plays a role in suppressing proinflammatory cytokine production, resulting in protection of mice from intestinal inflammation. These results reveal an integrated response of macrophages regulated by EGFR in intestinal inflammatory disorders.
巨噬细胞调节先天免疫以维持肠道内稳态,并在肠道炎症中发挥病理性作用。表皮生长因子受体 (EGFR) 的激活可促进多种细胞类型的细胞增殖、分化、存活和伤口闭合。然而,EGFR 在巨噬细胞中的作用尚不清楚。本研究旨在探讨巨噬细胞中 EGFR 的激活是否调节细胞因子的产生和肠道炎症。我们发现,葡聚糖硫酸钠 (DSS) 诱导的结肠炎小鼠和溃疡性结肠炎患者的结肠巨噬细胞中 EGFR 被激活。与 LysM-Cre 小鼠相比,骨髓细胞特异性 EGFR 缺失的 Egfr(fl/fl)LysM-Cre 小鼠的 DSS 诱导的急性结肠炎得到改善,并且从结肠炎中恢复得到促进。DSS 处理增加了结肠炎急性期的 IL-10 和 TNF 水平,并且在恢复期增加了 IL-10 但降低了 TNF 水平。抗 IL-10 中和 Ab 消除了巨噬细胞特异性 EGFR 缺失对 Egfr(fl/fl)LysM-Cre 小鼠 DSS 诱导的结肠炎的这些影响。LPS 刺激 EGFR 激活,抑制 EGFR 激酶活性增强了 LPS 刺激的 RAW 264.7 巨噬细胞中 NF-κB 的激活。此外,EGFR 激酶阻断的 RAW 264.7 细胞对 LPS 加 IFN-γ的反应诱导产生的 IL-10 增加与 TNF 产生减少相关。因此,尽管巨噬细胞中 EGFR 的选择性缺失导致对炎症刺激的促炎和抗炎细胞因子的增加,但 IL-10 水平的增加在抑制促炎细胞因子的产生中起作用,从而保护小鼠免受肠道炎症的影响。这些结果揭示了 EGFR 调节的巨噬细胞在肠道炎症性疾病中的综合反应。