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Myeloid‐specific blockade of Notch signaling alleviates murine pulmonary fibrosis through regulating monocyte‐derived Ly6c lo MHCII hi alveolar macrophages recruitment and TGF‐β secretion
Author(s) -
Zhang Ni,
Yang Kui,
Bai Jian,
Yi Jing,
Gao Chunchen,
Zhao Junlong,
Liang Shiqian,
Wei Tiaoxia,
Feng Lei,
Song Liqiang,
Han Hua,
Qin Hongyan
Publication year - 2020
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.201903086rr
Subject(s) - pulmonary fibrosis , monocyte , adoptive cell transfer , fibrosis , macrophage , myofibroblast , alveolar macrophage , ccr2 , chemistry , microbiology and biotechnology , conditional gene knockout , notch signaling pathway , inflammation , immunology , signal transduction , biology , medicine , chemokine , phenotype , immune system , t cell , biochemistry , chemokine receptor , gene , in vitro
Macrophages in lung, including resident alveolar macrophages (AMs) and interstitial macrophages (IMs), and monocyte‐derived macrophages, play important roles in pulmonary fibrosis (PF), but mechanisms underlying their differential regulation remain unclear. Recombination signal‐binding protein Jκ (RBP‐J)‐mediated Notch signaling regulates macrophage development and phenotype. Here, using bleomycin‐induced fibrosis model combined with myeloid‐specific RBP‐J disruption (RBP‐J cKO ) mouse, we investigated the role of Notch signaling in macrophages during PF. Compared with the control, RBP‐J cKO mice exhibited alleviated lung fibrosis as manifested by reduced collagen deposition and inflammation, and decreased TGF‐β production. FACS analysis suggested that decreased Ly6c lo MHCII hi AMs might make the major contribution to attenuated fibrogenesis in RBP‐J cKO mice, probably by reduced inflammatory factor release and enhanced matrix metalloproteinases expression. Using clodronate‐mediated macrophage depletion in RBP‐J ckO mice, we demonstrated that embryonic‐derived AMs play negligible role in lung fibrosis, which was further supported by adoptive transfer experiments. Moreover, on CCR2 knockout background, the effect of RBP‐J deficiency on fibrogenesis was not elicited, suggesting that Notch regulated monocyte‐derived AMs. Co‐culture experiment showed that monocyte‐derived AMs from RBP‐J cKO mice exhibit reduced myofibroblast activation due to decreased TGF‐β secretion. In conclusion, monocyte‐derived Ly6c lo MHCII hi AMs, which are regulated by RBP‐J‐mediated Notch signaling, play an essential role in lung fibrosis.