The role of MAPK and Nrf2 pathways in ketanserin-elicited attenuation of cigarette smoke-induced IL-8 production in human bronchial epithelial cells

Toxicol Sci. 2012 Feb;125(2):569-77. doi: 10.1093/toxsci/kfr305. Epub 2011 Nov 1.

Abstract

Cigarette smoking is a major risk factor in chronic obstructive pulmonary disease (COPD) with chronic airway inflammation as a key feature. Blockade of serotonin receptor 2A (5-HTR(2A)) with ketanserin has been found to improve lung function in COPD patients. Furthermore, ketanserin has been shown to possess anti-inflammatory properties in vivo. In this study, we investigated the antioxidative and anti-inflammatory properties of ketanserin and its underlying mechanism of action on cigarette smoke-induced interleukin (IL)-8 release in vitro. Primary normal human bronchial epithelial cells and human bronchial epithelial cell line (BEAS-2B) were treated with or without ketanserin prior to exposure to cigarette smoke medium (CSM). Exposure to CSM caused elevation of both mRNA and release of IL-8 with increased phosphorylation of p38 and extracellular signal-regulated kinases 1 and 2 (ERK1/2). Consistently, CSM-induced IL-8 release was blocked by SB203580, U0126, or MEK1 small interfering RNA (siRNA) but not SP600125. On the other hand, CSM caused a dose-dependent decrease in the ratio of reduced glutathione to oxidized glutathione (rGSH/GSSG) together with an increased translocation of Nrf2 to the nucleus demonstrated by Western blot analysis. Knock down of Nrf2 by siRNA completely blocked CSM-induced IL-8 release. Ketanserin suppressed CSM-induced IL-8 release by inhibiting p38, ERK1/2 MAPK, and Nrf2 signaling pathways and partially inhibited CSM-induced reduction of rGSH/GSSG ratio. Our data demonstrated the novel antioxidative and anti-inflammatory role of ketanserin via the Nrf2 signaling pathway in CSM-exposed human bronchial epithelial cells. This may open up new perspectives in the development of novel therapeutic targets in the treatment of cigarette smoke-related COPD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Inflammatory Agents / pharmacology*
  • Antioxidants / pharmacology*
  • Bronchi / drug effects*
  • Bronchi / enzymology
  • Cell Survival / drug effects
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Glutathione / metabolism
  • Humans
  • Interleukin-8 / genetics
  • Interleukin-8 / metabolism*
  • Ketanserin / pharmacology*
  • MAP Kinase Signaling System / drug effects*
  • MAP Kinase Signaling System / genetics
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • NF-E2-Related Factor 2 / genetics
  • NF-E2-Related Factor 2 / metabolism*
  • Oxidation-Reduction
  • Oxidative Stress / drug effects
  • Phosphorylation
  • Protein Kinase Inhibitors / pharmacology
  • RNA Interference
  • RNA, Messenger / metabolism
  • Receptor, Serotonin, 5-HT2A / drug effects*
  • Receptor, Serotonin, 5-HT2A / metabolism
  • Serotonin 5-HT2 Receptor Antagonists / pharmacology*
  • Smoke / adverse effects*
  • Smoking / adverse effects*
  • Time Factors
  • Transfection
  • Up-Regulation
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • Anti-Inflammatory Agents
  • Antioxidants
  • CXCL8 protein, human
  • Interleukin-8
  • NF-E2-Related Factor 2
  • NFE2L2 protein, human
  • Protein Kinase Inhibitors
  • RNA, Messenger
  • Receptor, Serotonin, 5-HT2A
  • Serotonin 5-HT2 Receptor Antagonists
  • Smoke
  • Ketanserin
  • MAPK1 protein, human
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • p38 Mitogen-Activated Protein Kinases
  • Glutathione