Pulmonary epithelial and pleural mesothelial cells are primary targets of inhaled environmental particulates including asbestos fibers and particulate matter (PM). Exposure of these cell types to asbestos or PM leads to increases in expression of the early response prot(o)oncogenes, c-jun and c-fos, which are linked to the development of apoptosis and/or proliferation in other cell types. Recently, we have shown that asbestos fibers, in contrast to a number of nonpathogenic particles, stimulate the Extracellular Signal-Related Kinase (ERK) cascade, i.e. Mitogen-Activated Protein Kinase (MAPK) , through a mechanism involving autophosphorylation of the Epidermal Growth Factor Receptor (EGFR). In this proposal, we will test the hypothesis (#1) that activation of the EGFR by asbestos fibers modulates the ERK cell signalling pathway and the development of apoptosis in rat pleural mesothelial (RPM) and rat alveolar type II epithelial (RLE) cells. A second hypothesis to be tested is that EGFR expression plays a role in the development of epithelial cell apoptosis, a possible repair mechanism in removal of proliferating type II epithelial cells, and pulmonary fibrosis after inhalation of asbestos. To verify these hypotheses, phosphorylation of EGFR, activation of ERKs vs. c-Jun amino terminal kinases (JNKs), apoptosis and proliferation will be examined in RPM and RLE in vitro after addition of chrysotile or crocidolite asbestos in the presence and absence of selective inhibitors of EGFR and in transfection experiments using dominant negative EGFR mutant constructs. Transgenic mice overexpressing dominant negative mutant EGFR in vivo using lung epithelial-cell specific promoters also will be exposed by inhalation to asbestos and characterized, using quantitative markers for cell proliferation, apoptosis, and fibrosis, to determine if the severity and extent of these outcomes are altered significantly in comparison to transgene-negative litter mates. Results will indicate if EGFR receptor activation and the MAPK signalling cascade are intrinsic to epithelial cell injury and lung disease by inhaled xenobiotics and lead to the development of therapeutic strategies in man.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
5R01ES009213-02
Application #
2796660
Study Section
Special Emphasis Panel (ZES1-LKB-A (R1))
Project Start
1997-09-30
Project End
2001-09-29
Budget Start
1998-09-30
Budget End
1999-09-29
Support Year
2
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Vermont & St Agric College
Department
Pathology
Type
Schools of Medicine
DUNS #
066811191
City
Burlington
State
VT
Country
United States
Zip Code
05405
Scapoli, Luca; Ramos-Nino, Maria E; Martinelli, Marcella et al. (2004) Src-dependent ERK5 and Src/EGFR-dependent ERK1/2 activation is required for cell proliferation by asbestos. Oncogene 23:805-13
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Ramos-Nino, Maria E; Scapoli, Luca; Martinelli, Marcella et al. (2003) Microarray analysis and RNA silencing link fra-1 to cd44 and c-met expression in mesothelioma. Cancer Res 63:3539-45
Ramos-Nino, Maria E; Heintz, Nicolas; Scappoli, Luca et al. (2003) Gene profiling and kinase screening in asbestos-exposed epithelial cells and lungs. Am J Respir Cell Mol Biol 29:S51-8
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Ramos-Nino, Maria E; Timblin, Cynthia R; Mossman, Brooke T (2002) Mesothelial cell transformation requires increased AP-1 binding activity and ERK-dependent Fra-1 expression. Cancer Res 62:6065-9
Reddy, Sekhar P M; Mossman, Brooke T (2002) Role and regulation of activator protein-1 in toxicant-induced responses of the lung. Am J Physiol Lung Cell Mol Physiol 283:L1161-78
Manning, Christopher B; Vallyathan, Val; Mossman, Brooke T (2002) Diseases caused by asbestos: mechanisms of injury and disease development. Int Immunopharmacol 2:191-200
Manning, Christopher B; Cummins, Andrew B; Jung, Michael W et al. (2002) A mutant epidermal growth factor receptor targeted to lung epithelium inhibits asbestos-induced proliferation and proto-oncogene expression. Cancer Res 62:4169-75

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