Activation of Swelling-activated Chloride Current by Tumor Necrosis Factor-α Requires ClC-3-dependent Endosomal Reactive Oxygen Production

• Published in: The Journal of biological chemistry Vol. 285; no. 30; pp. 22864 - 22873
• Main Authors: Matsuda, James J., Filali, Mohammed S., Moreland, Jessica G., Miller, Francis J., Lamb, Fred S.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 23.07.2010; American Society for Biochemistry and Molecular Biology
• Subjects: Animals; Cell Biology; Cell Line; Chloride Channels; Chloride Channels - metabolism; Chloride Transport; Chloride-Proton Antiporter; Chlorides - metabolism; Electric Conductivity; Endosomes - drug effects; Endosomes - metabolism; Hydrogen Peroxide - metabolism; Mice; Reactive Oxygen Species (ROS); Reactive Oxygen Species - metabolism; Signal Transduction; Swelling-activated Chloride Channel; Thrombin; Thrombin - pharmacology; Tumor Necrosis Factor (TNF); Tumor Necrosis Factor-alpha - pharmacology; Swelling-activated Chloride Channel; Reactive Oxygen Species (ROS); Chloride Channels; Tumor Necrosis Factor (TNF); Chloride-Proton Antiporter; Chloride Transport; Thrombin
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M109.099838

ClC-3 is a Cl−/H+ antiporter required for cytokine-induced intraendosomal reactive oxygen species (ROS) generation by Nox1. ClC-3 current is distinct from the swelling-activated chloride current (IClswell), but overexpression of ClC-3 can activate currents that resemble IClswell. Because H2O2 activates IClswell directly, we hypothesized that ClC-3-dependent, endosomal ROS production activates IClswell. Whole-cell perforated patch clamp methods were used to record Cl− currents in cultured aortic vascular smooth muscle cells from wild type (WT) and ClC-3 null mice. Under isotonic conditions, tumor necrosis factor-α (TNF-α) (10 ng/ml) activated outwardly rectifying Cl− currents with time-dependent inactivation in WT but not ClC-3 null cells. Inhibition by tamoxifen (10 μm) and by hypertonicity (340 mosm) identified them as IClswell. IClswell was also activated by H2O2 (500 μm), and the effect of TNF-α was completely inhibited by polyethylene glycol-catalase. ClC-3 expression induced IClswell in ClC-3 null cells in the absence of swelling or TNF-α, and this effect was also blocked by catalase. IClswell activation by hypotonicity (240 mosm) was only partially inhibited by catalase, and the size of these currents did not differ between WT and ClC-3 null cells. Disruption of endosome trafficking with either mutant Rab5 (S34N) or Rab11 (S25N) inhibited TNF-α-mediated activation of IClswell. Thrombin also activates ROS production by Nox1 but not in endosomes. Thrombin caused H2O2-dependent activation of IClswell, but this effect was not ClC-3- or Rab5-dependent. Thus, activation of IClswell by TNF-α requires ClC-3-dependent endosomal H2O2 production. This demonstrates a functional link between two distinct anion currents, ClC-3 and IClswell.