High-temperature calcined fullerene nanowhiskers as well as long needle-like multi-wall carbon nanotubes have abilities to induce NLRP3-mediated IL-1β secretion

• Published in: Biochemical and biophysical research communications 2014-09, Vol.452 (3), p.593-599
• Main Authors: Cui, Hongyan, Wu, Weijia, Okuhira, Keiichiro, Miyazawa, Kun’ichi, Hattori, Takayuki, Sai, Kimie, Naito, Mikihiko, Suzuki, Kazuhiro, Nishimura, Tetsuji, Sakamoto, Yoshimitsu, Ogata, Akio, Maeno, Tomokazu, Inomata, Akiko, Nakae, Dai, Hirose, Akihiko, Nishimaki-Mogami, Tomoko
• Format: Article
• Language: English
• Subjects: Amino Acid Chloromethyl Ketones - pharmacology; Carbon nanotubes; Carrier Proteins - antagonists & inhibitors; Carrier Proteins - genetics; Carrier Proteins - metabolism; Caspase 1 - genetics; Caspase 1 - metabolism; Caspase Inhibitors - pharmacology; Cell Line; Fullerene nanowhiskers; Fullerenes - chemistry; Fullerenes - pharmacology; Gene Expression; Hot Temperature; Humans; IL-1β; Inflammasomes - drug effects; Inflammasomes - metabolism; Interleukin-1beta - biosynthesis; Interleukin-1beta - secretion; Macrophages - cytology; Macrophages - drug effects; Macrophages - metabolism; Nanofibers - chemistry; Nanofibers - toxicity; Nanotubes, Carbon - chemistry; Nanotubes, Carbon - toxicity; NLR Family, Pyrin Domain-Containing 3 Protein; NLRP3; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2014.08.118

•Metal impurities in carbon nanotubes may be responsible for their toxicity.•Fullerene nanowhiskers have similar sizes and shape but no metal impurities.•Long high-temperature calcined fullerene nanowhiskers induce IL-1β secretion.•Knockdown of NLRP3 abolished the IL-1β secretion.•Needle-like shape and size but not metal impurities were critical to NLRP3 activation. Because multi-wall carbon nanotubes (MWCNTs) have asbestos-like shape and size, concerns about their pathogenicity have been raised. Contaminated metals of MWCNTs may also be responsible for their toxicity. In this study, we employed high-temperature calcined fullerene nanowhiskers (HTCFNWs), which are needle-like nanofibers composed of amorphous carbon having similar sizes to MWCNTs but neither metal impurities nor tubular structures, and investigated their ability to induce production a major proinflammatory cytokine IL-1β via the Nod-like receptor pyrin domain containing 3 (NLRP3)-containing flammasome-mediated mechanism. When exposed to THP-1 macrophages, long-HTCFNW exhibited robust IL-1β production as long and needle-like MWCNTs did, but short-HTCFNW caused very small effect. IL-1β release induced by long-HTCFNW as well as by long, needle-like MWCNTs was abolished by a caspase-1 inhibitor or siRNA-knockdown of NLRP3, indicating that NLRP3-inflammasome-mediated IL-1β production by these carbon nanofibers. Our findings indicate that the needle-like shape and length, but neither metal impurities nor tubular structures of MWCNTs were critical to robust NLRP3 activation.