title: TRPM2 channels in alveolar epithelial cells mediate bleomycin-induced lung inflammation.
abstract: Lung inflammation is a major adverse effect of therapy with the antitumor drug bleomycin (BLM). Transient receptor potential melastatin 2 (TRPM2) is a Ca(2+)-permeable channel that is activated by oxidative stress through the production of ADP-ribose. We herein investigated whether TRPM2 channels contributed to BLM-induced lung inflammation. The intratracheal instillation of BLM into wild-type (WT) mice increased the number of polymorphonuclear leukocytes (PMNs) and inflammatory cytokine levels in the lung. Increases in inflammatory markers in WT mice were markedly reduced in trpm2 knockout (KO) mice, which demonstrated that the activation of TRPM2 channels was involved in BLM-induced lung inflammation. The expression of TRPM2 mRNA was observed in alveolar macrophages, alveolar epithelial cells, and lung fibroblasts. Actually, TRPM2 protein was expressed in lung tissues. Of these, TRPM2 channels in epithelial cells were activated by the addition of H2O2 following a BLM pretreatment, resulting in the secretion of macrophage inflammatory protein-2 (MIP-2). The H2O2-induced activation of TRPM2 by the BLM pretreatment was blocked by the poly(ADP-ribose) polymerase (PARP) inhibitors PJ34 and 3-aminobenzamide. The accumulation of poly(ADP-ribose) in the nucleus, a marker for ADP-ribose production, was strongly induced by H2O2 following the BLM pretreatment. Furthermore, administration of PRAP inhibitors into WT mice markedly reduced recruitment of inflammatory cells and MIP-2 secretion induced by BLM instillation. These results suggest that the induction of MIP-2 secretion through the activation of TRPM2 channels in alveolar epithelial cells is an important mechanism in BLM-induced lung inflammation, and the TRPM2 activation is likely to be mediated by ADP-ribose production via PARP pathway. TRPM2 channels may be new therapeutic target for BLM-induced lung inflammation.
authors.affiliation: Division of Physiology and Pathology, Department of Pharmacology, Toxicology and Therapeutics, Showa University School of Pharmacy, Tokyo, Japan; Division of Pharmacology, Faculty of Pharmaceutical Sciences, Teikyo Heisei University, 4-21-2 Nakano, Nakano-ku, Tokyo 164-8530, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Yonezawa
authors.affiliation: Division of Pharmacology, Faculty of Pharmaceutical Sciences, Teikyo Heisei University, 4-21-2 Nakano, Nakano-ku, Tokyo 164-8530, Japan; Department of Molecular Cell Biology and Medicine, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Japan.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Yamamoto
authors.affiliation: Division of Physiology and Pathology, Department of Pharmacology, Toxicology and Therapeutics, Showa University School of Pharmacy, Tokyo, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Takenaka
authors.affiliation: Division of Physiology and Pathology, Department of Pharmacology, Toxicology and Therapeutics, Showa University School of Pharmacy, Tokyo, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Kage
authors.affiliation: Department of Pharmacogenomics, Showa University School of Pharmacy, Tokyo, Japan.
authors.forename: Takaharu
authors.initials: T
authors.lastname: Negoro
authors.affiliation: Laboratory of Pharmacology, Department of Clinical Pharmacy, Yokohama College of Pharmacy, Yokohama, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Toda
authors.affiliation: Division of Clinical Pharmacy, Department of Pharmacotherapeutics, Showa University School of Pharmacy, Tokyo, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ohbayashi
authors.affiliation: Department of Physiology, Graduate School of Medical Sciences, Fukuoka University, Fukuoka, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Numata
authors.affiliation: Department of Pharmacogenomics, Showa University School of Pharmacy, Tokyo, Japan.
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Nakano
authors.affiliation: Division of Clinical Pharmacy, Department of Pharmacotherapeutics, Showa University School of Pharmacy, Tokyo, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Mori
authors.affiliation: Division of Physiology and Pathology, Department of Pharmacology, Toxicology and Therapeutics, Showa University School of Pharmacy, Tokyo, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Ishii
authors.affiliation: Division of Physiology and Pathology, Department of Pharmacology, Toxicology and Therapeutics, Showa University School of Pharmacy, Tokyo, Japan; Division of Pharmacology, Faculty of Pharmaceutical Sciences, Teikyo Heisei University, 4-21-2 Nakano, Nakano-ku, Tokyo 164-8530, Japan; Laboratory of Pharmacology, Department of Clinical Pharmacy, Yokohama College of Pharmacy, Yokohama, Japan. Electronic address: s.shimizu@thu.ac.jp.
authors.forename: Shunichi
authors.initials: S
authors.lastname: Shimizu
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000633:toxicity*; D001761:Bleomycin / Q000633:toxicity*; D016207:Cytokines / Q000096:biosynthesis; D004847:Epithelial Cells / Q000502:physiology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000633:toxicity; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009504:Neutrophils / Q000276:immunology; D011014:Pneumonia / Q000139:chemically induced*; D000071137:Poly (ADP-Ribose) Polymerase-1; D000067856:Poly(ADP-ribose) Polymerase Inhibitors / Q000494:pharmacology; D011065:Poly(ADP-ribose) Polymerases / Q000502:physiology; D011650:Pulmonary Alveoli / Q000502:physiology*; D050053:TRPM Cation Channels / Q000032:analysis / Q000235:genetics / Q000502:physiology*
chemical_list: D000903:Antibiotics, Antineoplastic; D016207:Cytokines; D008070:Lipopolysaccharides; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D050053:TRPM Cation Channels; C544443:TRPM2 protein, mouse; D001761:Bleomycin; D006861:Hydrogen Peroxide; C499321:Parp1 protein, mouse; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases
keywords: Bleomycin; H(2)O(2); Lung inflammation; Oxidative-stress; TRPM2