Monocarboxylate transporter-1 is required for cell death in mouse chondrocytic ATDC5 cells exposed to interleukin-1beta via late phase activation of nuclear factor kappaB and expression of phagocyte-type NADPH oxidase

• Published in: The Journal of biological chemistry 2011-04, Vol.286 (17), p.14744-14752
• Main Authors: Yoshimura, Kentaro, Miyamoto, Yoichi, Yasuhara, Rika, Maruyama, Toshifumi, Akiyama, Tomohito, Yamada, Atsushi, Takami, Masamichi, Suzawa, Tetsuo, Tsunawaki, Shoko, Tachikawa, Tetsuhiko, Baba, Kazuyoshi, Kamijo, Ryutaro
• Format: Article
• Language: English
• Subjects: Animals; Cell Death; Cell Line; Chondrocytes - cytology; Interleukin-1beta - pharmacology; Mice; Monocarboxylic Acid Transporters - physiology; NADPH Oxidases - biosynthesis; NF-kappa B - metabolism; Nitric Oxide Synthase Type II - biosynthesis; Phagocytosis; Reactive Oxygen Species; Symporters - physiology
• ISSN: 1083-351X
• DOI: 10.1074/jbc.M111.221259

Interleukin-1β (IL-1β) induces cell death in chondrocytes in a nitric oxide (NO)- and reactive oxygen species (ROS)-dependent manner. In this study, increased production of lactate was observed in IL-1β-treated mouse chondrocytic ATDC5 cells prior to the onset of their death. IL-1β-induced cell death in ATDC5 cells was suppressed by introducing an siRNA for monocarboxylate transporter-1 (MCT-1), a lactate transporter distributed in plasma and mitochondrial inner membranes. Mct-1 knockdown also prevented IL-1β-induced expression of phagocyte-type NADPH oxidase (NOX-2), an enzyme specialized for production of ROS, whereas it did not have an effect on inducible NO synthase. Suppression of IL-1β-induced cell death by Nox-2 siRNA indicated that NOX-2 is involved in cell death. Phosphorylation and degradation of inhibitor of κBα (IκBα) from 5 to 20 min after the addition of IL-1β was not affected by Mct-1 siRNA. In addition, IκBα was slightly decreased after 12 h of incubation with IL-1β, and the decrease was prominent after 36 h, whereas activation of p65/RelA was observed from 12 to 48 h after exposure to IL-1β. These changes were not seen in Mct-1-silenced cells. Forced expression of IκBα super repressor as well as treatment with the IκB kinase inhibitor BAY 11-7082 suppressed NOX-2 expression. Furthermore, Mct-1 siRNA lowered the level of ROS generated after 15-h exposure to IL-1β, whereas a ROS scavenger, N-acetylcysteine, suppressed both late phase degradation of IκBα and Nox-2 expression. These results suggest that MCT-1 contributes to NOX-2 expression via late phase activation of NF-κB in a ROS-dependent manner in ATDC5 cells exposed to IL-1β.