title: MafB enhances the phagocytic activity of RAW264.7 macrophages by promoting Fcgr3 expression.
abstract: This study was designed to investigate whether MafB influences the phagocytic activity of macrophages by modulating the expression of the Fc receptors for IgG (FcγRs), Fcgr2b and Fcgr3. In macrophages, FcγRs are critical for the phagocytosis of opsonized pathogens. Of these receptors, Fcgr3 has been shown to play an important role in host defense. As a model to evaluate the mechanism by which MafB influences phagocytosis, we utilized a macrophage cell-line that constitutively expresses a MafB-specific short hairpin (sh)RNA (RAW264.7-MafB-shRNA). Specifically, the levels of Fc receptor mediated-phagocytosis and the levels of FcγRs surface expression were evaluated by flow cytometry analysis, while quantitative real-time PCR analysis was utilized to examine the mRNA expression levels of FcγRs. Compared to the control cell population, RAW264.7-MafB-shRNA cells exhibited significant reductions in Fcgr3 expression and Fc receptor-mediated phagocytosis, but no difference in Fcgr2b expression. Likewise, there was markedly decreased surface expression of Fcgr3 antigen, but not Fcgr2b antigen, in RAW264.7-MafB-shRNA, compared to the control cells. Meanwhile, the observed reduction in the phagocytic activity of the MafB-shRNA-expressing cells was attenuated by ectopic expression of Fcgr3. Together, the results presented here indicate that MafB influences the phagocytic activity of macrophages by promoting Fcgr3, but not Fcgr2b, expression.
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Nemoto
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan. Electronic address: shibata@med.id.yamagata-u.ac.jp.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Shibata
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
authors.forename: Sumito
authors.initials: S
authors.lastname: Inoue
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Igarashi
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
authors.forename: Yoshikane
authors.initials: Y
authors.lastname: Tokairin
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Yamauchi
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Kimura
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
authors.forename: Masamichi
authors.initials: M
authors.lastname: Sato
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
authors.forename: Kento
authors.initials: K
authors.lastname: Sato
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakano
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Abe
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Nishiwaki
authors.affiliation: Department of Cardiology, Pulmonology, and Nephrology, Yamagata University School of Medicine, Yamagata, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Kubota
mesh_terms: D000818:Animals; D008262:Macrophage Activation / Q000502:physiology*; D051258:MafB Transcription Factor / Q000378:metabolism*; D051379:Mice; D010587:Phagocytosis / Q000502:physiology*; D000067996:RAW 264.7 Cells; D017452:Receptors, IgG / Q000378:metabolism*; D015854:Up-Regulation / Q000502:physiology
chemical_list: C485700:Fcgr3 protein, mouse; D051258:MafB Transcription Factor; C490406:Mafb protein, mouse; D017452:Receptors, IgG
keywords: CD16; Fcgr3; Macrophage; MafB; Phagocytosis