Role of mitochondrial hydrogen peroxide induced by intermittent hypoxia in airway epithelial wound repair in vitro.
The airway epithelium acts as a frontline barrier against various environmental insults and its repair process after airway injury is critical for the lung homeostasis restoration. Recently, the role of intracellular reactive oxygen species (ROS) as transcription-independent damage signaling has been highlighted in the wound repair process. Both conditions of continuous hypoxia and intermittent hypoxia (IH) induce ROS. Although IH is important in clinical settings, the roles of IH-induced ROS in the airway repair process have not been investigated. In this study, we firstly showed that IH induced mitochondrial hydrogen peroxide (H2O2) production and significantly decreased bronchial epithelial cell migration, prevented by catalase treatment in a wound scratch assay. RhoA activity was higher during repair process in the IH condition compared to in the normoxic condition, resulting in the cellular morphological changes shown by immunofluorescence staining: round cells, reduced central stress fiber numbers, pronounced cortical actin filament distributions, and punctate focal adhesions. These phenotypes were replicated by exogenous H2O2 treatment under the normoxic condition. Our findings confirmed the transcription-independent role of IH-induced intracellular ROS in the bronchial epithelial cell repair process and might have significant implications for impaired bronchial epithelial cell regeneration.
Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: sh1124@kuhp.kyoto-u.ac.jp.
Satoshi
S
Hamada
Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: atsuyasu@kuhp.kyoto-u.ac.jp.
Atsuyasu
A
Sato
Center for Innovation in Immunoregulative Technology and Therapeutics, Graduate School of Medicine, Kyoto University, Yoshida Konoecho, Kyoto 606-8501, Japan. Electronic address: haramari@kuhp.kyoto-u.ac.jp.
Mariko
M
Hara-Chikuma
Center for Innovation in Immunoregulative Technology and Therapeutics, Graduate School of Medicine, Kyoto University, Yoshida Konoecho, Kyoto 606-8501, Japan. Electronic address: hirosatooka@ak.med.kyoto-u.ac.jp.
Hiroki
H
Satooka
Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: hase0111@kuhp.kyoto-u.ac.jp.
Koichi
K
Hasegawa
Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: tanigue1981@yahoo.co.jp.
Kazuya
K
Tanimura
Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: tanizawa@kuhp.kyoto-u.ac.jp.
Kiminobu
K
Tanizawa
Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: inouchi@kuhp.kyoto-u.ac.jp.
Morito
M
Inouchi
Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: hanta@kuhp.kyoto-u.ac.jp.
Tomohiro
T
Handa
Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: ogato@kuhp.kyoto-u.ac.jp.
Toru
T
Oga
Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: smuro@kuhp.kyoto-u.ac.jp.
Shigeo
S
Muro
Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: mishima@kuhp.kyoto-u.ac.jp.
Michiaki
M
Mishima
Department of Respiratory Care and Sleep Control Medicine, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan. Electronic address: chink@kuhp.kyoto-u.ac.jp.
Kazuo
K
Chin
D008841:Actin Cytoskeleton / Q000378:metabolism; D002448:Cell Adhesion; D015687:Cell Hypoxia; D002460:Cell Line; D002465:Cell Movement; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000378:metabolism* / Q000473:pathology*; D022001:Focal Adhesions / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008168:Lung / Q000473:pathology*; D008928:Mitochondria / Q000378:metabolism*; D014945:Wound Healing; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
D006861:Hydrogen Peroxide; D020742:rhoA GTP-Binding Protein
Actin cytoskeleton; Intermittent hypoxia; Reactive oxygen species; RhoA; Transcription-independent manner; Wound repair