title: Purinergic signaling via P2X7 receptor mediates IL-1β production in Kupffer cells exposed to silica nanoparticle.
abstract: There is extensive evidence that nanoparticles (NPs) cause adverse effects in multiple organs, including liver, though the mechanisms involved remain to be fully established. Kupffer cells are macrophages resident in the liver, and play important roles in liver inflammation induced by various toxic agents, including lipopolysaccharide (LPS). Interleukin-1 (IL-1) family members IL-1α,β are released from LPS-primed macrophages exposed to NPs, including silica NPs (SNPs), via activation of nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 inflammasomes. Here, we investigated the mechanism of production of IL-1β via activation of inflammasomes in mouse Kupffer cell line KUP5, focusing on the role of purinergic signaling via P2X7 receptor. IL-1β production by LPS-primed KUP5 cells exposed to SNPs was increased dose-dependently, and was greatest in response to SNPs with a diameter of 30 nm (SNP30), as compared with 70-nm and 300-nm SNPs (SNP70 and SNP300). ATP release was also highest in cells exposed to SNP30. Treatment of LPS-primed KUP5 cells with ATP also induced a high level of IL-1β production, similar to that induced by SNP30. IL-1β production was significantly inhibited by apyrase (an ecto-nucleotidase) and A438079 (a P2X7 antagonist/ATP-release inhibitor). Production of reactive oxygen species (ROS) was confirmed in cells exposed to SNP30. In conclusion, ATP released from P2X7 receptor in response to stimulation of KUP5 cells with SNP30 induces ROS production via cell-membrane NADPH oxidase. The ROS causes activation of inflammasomes, leading to caspase-1-dependent processing of IL-1β.
authors.affiliation: Department of Radiation Biosciences, Faculty of Pharmaceutical Sciences, Tokyo University of Science (TUS), 2641 Yamazaki, Noda-shi, Chiba 278-8510, Japan. Electronic address: kjma@rs.noda.tus.ac.jp.
authors.forename: Shuji
authors.initials: S
authors.lastname: Kojima
authors.affiliation: Department of Radiation Biosciences, Faculty of Pharmaceutical Sciences, Tokyo University of Science (TUS), 2641 Yamazaki, Noda-shi, Chiba 278-8510, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Negishi
authors.affiliation: Department of Radiation Biosciences, Faculty of Pharmaceutical Sciences, Tokyo University of Science (TUS), 2641 Yamazaki, Noda-shi, Chiba 278-8510, Japan.
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Tsukimoto
authors.affiliation: Transgenic Animal Research Center, National Institute of Agrobiological Sciences, Ohwashi 1-2, Tsuuba, Ibaraki 305-8634, Japan.
authors.forename: Takato
authors.initials: T
authors.lastname: Takenouchi
authors.affiliation: Transgenic Animal Research Center, National Institute of Agrobiological Sciences, Ohwashi 1-2, Tsuuba, Ibaraki 305-8634, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kitani
authors.affiliation: Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Tokyo University of Science (TUS), 2641 Yamazaki, Noda-shi, Chiba 278-8510, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Takeda
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D053583:Interleukin-1beta / Q000096:biosynthesis*; D007728:Kupffer Cells / Q000187:drug effects / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D053758:Nanoparticles / Q000633:toxicity*; D020641:Polymorphism, Single Nucleotide / Q000187:drug effects; D061251:Primary Cell Culture; D017382:Reactive Oxygen Species; D058486:Receptors, Purinergic P2X7 / Q000187:drug effects / Q000502:physiology*; D012822:Silicon Dioxide / Q000633:toxicity*
chemical_list: D000975:Antioxidants; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D017382:Reactive Oxygen Species; D058486:Receptors, Purinergic P2X7; D012822:Silicon Dioxide; D000255:Adenosine Triphosphate
keywords: ATP; IL-1β; Inflammasome; Kupffer cell; P2X(7) receptor; Silica nanoparticle