Asbestos induces mitochondrial DNA damage and dysfunction linked to the development of apoptosis

• Published in: American journal of physiology. Lung cellular and molecular physiology 2003-11, Vol.285 (5), p.1018-L1025
• Main Authors: Shukla, Arti, Jung, Michael, Stern, Maria, Fukagawa, Naomi K, Taatjes, Douglas J, Sawyer, Dennis, Van Houten, Bennett, Mossman, Brooke T
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis - drug effects; Asbestos - toxicity; Cell Division - drug effects; Cells, Cultured; DNA Damage; DNA, Mitochondrial - drug effects; DNA, Mitochondrial - genetics; Dose-Response Relationship, Drug; Hydrogen Peroxide - toxicity; Oxidative Stress; Pleural Cavity; Polymerase Chain Reaction - methods; Rats; Rats, Inbred F344; Respiratory Mucosa - drug effects; Respiratory Mucosa - pathology; Respiratory Mucosa - physiology
• ISSN: 1040-0605; 1522-1504
• DOI: 10.1152/ajplung.00038.2003

1 Department of Pathology, University of Vermont College of Medicine, Burlington, Vermont 05405; 2 University of Texas at Galveston, Galveston, Texas 77555; and 3 National Institutes of Environmental Health Sciences, Research Triangle Park, North Carolina 27709 Submitted 6 February 2003 ; accepted in final form 20 July 2003 To test the hypothesis that asbestos-mediated cell injury is mediated through an oxidant-dependent mitochondrial pathway, isolated mesothelial cells were examined for mitochondrial DNA damage as determined by quantitative PCR. Mitochondrial DNA damage occurred at fourfold lower concentrations of crocidolite asbestos compared with concentrations required for nuclear DNA damage. DNA damage by asbestos was preceded by oxidant stress as shown by confocal scanning laser microscopy using MitoTracker Green FM and the oxidant probe Redox Sensor Red CC-1. These events were associated with dose-related decreases in steady-state mRNA levels of cytochrome c oxidase, subunit 3 (COIII), and NADH dehydrogenase 5. Subsequently, dose-dependent decreases in formazan production, an indication of mitochondrial dysfunction, increased mRNA expression of pro- and antiapoptotic genes, and increased numbers of apoptotic cells were observed in asbestos-exposed mesothelial cells. The possible contribution of mitochondrial-derived pathways to asbestos-induced apoptosis was confirmed by its significant reduction after pretreatment of cells with a caspase-9 inhibitor. Apoptosis was decreased in the presence of catalase. Last, use of HeLa cells transfected with a mitochondrial transport sequence targeting the human DNA repair enzyme 8-oxoguanine DNA glycosylase to mitochondria demonstrated that asbestos-induced apoptosis was ameliorated with increased cell survival. Studies collectively indicate that mitochondria are initial targets of asbestos-induced DNA damage and apoptosis via an oxidant-related mechanism. mitochondria; mesothelial cells; oxidants Address for reprint requests and other correspondence: B. T. Mossman, Dept. of Pathology, Univ. of Vermont College of Medicine, 89 Beaumont Ave., Burlington, VT 05405 (E-mail: Brooke.Mossman{at}uvm.edu ).