Inflammatory responses induce an identity crisis of alveolar macrophages, leading to pulmonary alveolar proteinosis

Risa Ebina-Shibuya, Mitsuyo Matsumoto, Makoto Kuwahara, Kyoung Jin Jang, Manabu Sugai, Yoshiaki Ito, Ryo Funayama, Keiko Nakayama, Yuki Sato, Naoto Ishii, Yasunobu Okamura, Kengo Kinoshita, Kohei Kometani, Tomohiro Kurosaki, Akihiko Muto, Masakazu Ichinose, Masakatsu Yamashita, Kazuhiko Igarashia

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Pulmonary alveolar proteinosis (PAP) is a severe respiratory disease characterized by dyspnea caused by accumulation of surfactant protein. Dysfunction of alveolar macrophages (AMs), which regulate the homeostasis of surfactant protein, leads to the development of PAP; for example, in mice lacking BTB and CNC homology 2 (Bach2). However, how Bach2 helps prevent PAP is unknown, and the cell-specific effects of Bach2 are undefined. Using mice lacking Bach2 in specific cell types, we found that the PAP phenotype of Bach2-deficient mice is due to Bach2 deficiency in more than two types of immune cells. Depletion of hyperactivated T cells in Bach2-deficient mice restored normal function of AMs and ameliorated PAP. We also found that, in Bach2-deficient mice, hyperactivated T cells induced gene expression patterns that are specific to other tissue-resident macrophages and dendritic cells. Moreover, Bach2-deficient AMs exhibited a reduction in cell cycle progression. IFN-released from T cells induced Bach2 expression in AMs, in which Bach2 then bound to regulatory regions of inflammationassociated genes in myeloid cells. Of note, in AMs, Bach2 restricted aberrant responses to excessive T cell-induced inflammation, whereas, in T cells, Bach2 puts a brake on T cell activation. Moreover, Bach2 stimulated the expression of multiple histone genes in AMs, suggesting a role of Bach2 in proper histone expression. We conclude that Bach2 is critical for the maintenance of AM identity and self-renewal in inflammatory environments. Treatments targeting T cells may offer new therapeutic strategies for managing secondary PAP.

Original languageEnglish
Pages (from-to)18098-18112
Number of pages15
JournalJournal of Biological Chemistry
Issue number44
Publication statusPublished - 2017 Nov 3


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