title: Carbon nanotubes activate macrophages into a M1/M2 mixed status: recruiting naïve macrophages and supporting angiogenesis.
abstract: The potential of carbon nanotubes (CNTs) in medical applications has been attracting constant research interest as well as raising concerns related to toxicity. The immune system serves as the first line of defense against invasion. In this work, interactions of oxidized multiwalled carbon nanotubes (MWCNT) with macrophages were investigated to unravel the activation profile of macrophages, using cytokine array, ELISA assay, transwell assay, confocal microscopy, and reactive oxygen species examination. Results show that MWCNT initiate phagocytosis of macrophages and upregulate CD14, CD11b, TLR-4/MD2, and CD206, which does not alter the MHCII expression of the macrophages. The macrophages engulfing MWCNT (MWCNT-RAW) secrete a large amount of MIP-1α and MIP-2 to recruit naïve macrophages and produce angiogenesis-related cytokines MMP-9 and VEGF, while inducing much lower levels of proinflammatory cytokines than those activated by LPS. In conclusion, MWCNT activate macrophages into a M1/M2 mixed status, which allows the cells to recruit naïve macrophages and support angiogenesis.
authors.affiliation: Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing 100005, P. R. China.
authors.forename: Jie
authors.initials: J
authors.lastname: Meng
authors.forename: Xiaojin
authors.initials: X
authors.lastname: Li
authors.forename: Chuan
authors.initials: C
authors.lastname: Wang
authors.forename: Hua
authors.initials: H
authors.lastname: Guo
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Haiyan
authors.initials: H
authors.lastname: Xu
mesh_terms: D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D016207:Cytokines / Q000276:immunology; D008262:Macrophage Activation / Q000187:drug effects / Q000276:immunology*; D008264:Macrophages / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D049329:Nanostructures / Q000008:administration & dosage*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000276:immunology*; D017382:Reactive Oxygen Species / Q000276:immunology*
chemical_list: D016207:Cytokines; D037742:Nanotubes, Carbon; D017382:Reactive Oxygen Species
keywords: angiogenesis; carbon nanotubes; macrophage activation; phenotype; recruitment