Nitrative DNA damage induced by carbon-black nanoparticles in macrophages and lung epithelial cells.

Abstract

Carbon black (CB) is a nanomaterial used mainly in rubber products. Exposure to CB by inhalation causes malignant lung tumors in experimental animals. CB inhalation may cause chronic inflammation in the respiratory system, leading to carcinogenesis, but the mechanism remains unclear. Reactive oxygen and nitrogen species are generated from inflammatory and epithelial cells under inflammatory conditions, and resulting DNA damage may contribute to carcinogenesis. In this study, we performed immunocytochemistry to determine whether CB exposure induces formation of 8-nitroguanine (8-nitroG), a nitrative DNA lesion formed under inflammatory conditions, in RAW 264.7 macrophage and A549 lung epithelial cells. We compared the DNA-damaging effects of CB particles with primary diameter 56nm (CB56) and 95nm (CB95). Both types of CB induced 8-nitroG formation, mainly in the nucleus of RAW 264.7 and A549 cells, and CB95 tended to induce more 8-nitroG formation than did CB56. Flow cytometry revealed that CB95 generated larger amount of reactive oxygen species than did CB56 in RAW 264.7 cells. The Griess method showed that CB95 produced significantly larger amount of nitric oxide (NO) than did CB56. Flow cytometry showed that CB95 was more efficiently internalized into the cells than was CB56. The cellular uptake of CB and 8-nitroG formation in RAW 264.7 cells were reduced by monodansylcadaverine, an inhibitor of clathrin-mediated endocytosis, and by siRNA for Ctlc (clathrin heavy chain) gene. CB induces nitrative DNA damage in cultured cells, and clathrin-mediated endocytosis is involved, at least in part.

• Authors: Yusuke Hiraku, Yoshihiro Nishikawa, Ning Ma, Tahmina Afroz, Kosuke Mizobuchi, Ryo Ishiyama, Yuta Matsunaga, Takamichi Ichinose, Shosuke Kawanishi, Mariko Murata
• Journal: Mutation research. Genetic toxicology and environmental mutagenesis (Mutat Res Genet Toxicol Environ Mutagen) Vol. 818 Pg. 7-16 (Jun 2017) ISSN: 1879-3592 [Electronic] Netherlands
• PMID: 28477879 (Publication Type: Journal Article)
• Copyright: Copyright © 2017 Elsevier B.V. All rights reserved.

Chemical References

• 8-nitroguanine
• Clathrin
• Reactive Oxygen Species
• Soot
• Nitric Oxide
• Guanine
• NOS2 protein, human
• Nitric Oxide Synthase Type II
• Nos2 protein, mouse

Topics

• A549 Cells
• Alveolar Epithelial Cells (drug effects, metabolism, pathology)
• Animals
• Cell Culture Techniques
• Cell Survival (drug effects, genetics)
• Clathrin (genetics)
• DNA Damage
• Endocytosis (drug effects)
• Guanine (analogs & derivatives, biosynthesis)
• Humans
• Macrophages (drug effects, metabolism, pathology)
• Mice
• Nanoparticles (chemistry, toxicity)
• Nitric Oxide (metabolism)
• Nitric Oxide Synthase Type II (genetics)
• Particle Size
• Reactive Oxygen Species (metabolism)
• Soot (chemistry, toxicity)
• Surface Properties
• Transfection