Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

Essential role of p53 in silica-induced apoptosis.

Authors
Wang-LY; Bowman-L; Lu-YJ; Rojanasakul-Y; Mercer-RR; Castranova-V; Ding-M
Source
Am J Physiol, Lung Cell Mol Physiol 2005 Mar; 288(3):L488-L496
NIOSHTIC No.
20026151
Abstract
Occupational exposure to mineral dusts, such as silica, has been associated with progressive pulmonary inflammation, lung cancer, and fibrosis. However, the mechanisms involved in this process are poorly understood. Because p53 is a key transcription factor regulating many important apoptosis-related genes, we hypothesized that p53 may play a key role in silica-induced apoptosis and that abnormal regulation of p53 by silica may contribute to development of lung cancer as well as silicosis. We used both in vitro and in vivo studies to test this hypothesis. Treatment of JB6 cells carrying a p53-luciferase reporter plasmid with silica caused dose-dependent p53 transactivation. Western blot indicates that silica not only stimulated p53 protein expression but also caused p53 phosphorylation at Ser392. TUNEL and DNA fragmentation analysis show that silica caused apoptosis in both JB6 cells and wild-type p53 (p53+/+) fibroblasts but not in p53-deficient (p53-/-) fibroblasts. Similar results were obtained by in vivo studies. Intratracheal instillation of mice with silica induced apoptosis in the lung of p53+/+ mice, whereas this induction was significantly inhibited in p53-/- mice. Confocal image analysis indicates that most apoptotic cells induced by silica were alveolar macrophages. These results demonstrate for the first time that silica induces p53 transactivation via induction of p53 protein expression and phosphorylation of p53 protein and that p53 plays a crucial role in the signal transduction pathways of silica-induced apoptosis. This finding may provide an important link in understanding the molecular mechanisms of silica-induced carcinogenesis and pathogenesis in the lung.
Keywords
Mineral-dusts; Silica-dusts; Pulmonary-system-disorders; Respiratory-system-disorders; Lung-fibrosis; Lung-disease; Lung-disorders; Fibrogenesis; Fibrogenicity; Laboratory-animals; Animals; Animal-studies; Particulates; Particulate-dust; Aerosol-particles; Aerosols
Contact
M. Ding, Pathology and Physiology Research Branch, National Inst. for Occupational Safety and Health, Morgantown, WV 26505
CODEN
APLPE7
CAS No.
14808-60-7
Publication Date
20050301
Document Type
Journal Article
Email Address
mid5@cdc.gov
Fiscal Year
2005
NTIS Accession No.
NTIS Price
Issue of Publication
3
ISSN
1040-0605
NIOSH Division
HELD
Source Name
American Journal of Physiology: Lung Cellular and Molecular Physiology
State
WV
TOP