The purpose of this proposal is to prepare myself for a career as an independent cell and molecular biology researcher in pulmonary diseases with a focus on the mechanism of lung fibrosis. The hypothesis to be tested directly in this proposal is that human lung fibroblast proliferation is mediated in vitro by platelet-derived growth factor (PDGF) A-chain through an autocrine proliferative mechanism. Furthermore, I postulate that this PDGF-A chain autocrine proliferative mechanism is an integral component of developing fibrogenic pulmonary disease. I have previously identified asbestos-induced PDGF-dependent autocrine fibroblast proliferation in rat lung fibroblasts in vitro. Investigation into PDGF- dependent autocrine mitogenesis appears to have importance because many growth factors induce fibroblast proliferation through this PDGF-dependent mechanism in vitro. In this proposal I will first validate my preliminary data that human lung fibroblast also proliferate via a PDGF-dependent autocrine mechanism, using cell proliferation assays, Western and Northern analysis, radioreceptor assays. Antisense oligonucleotides will also be used to block the PDGF A-chain ligand and thus, confirm the presence of human autocrine PDGF-A dependent proliferation in vitro. Next, I will establish whether the receptor and ligand components of the PDGF-dependent autocrine loop are present in lung mesenchymal cells during the process of scar formation in vivo using our morphologically characterized murine model of asbestos-induced lung fibrosis, histochemical immunostaining and in situ hybridization. Then, I will manipulate the autocrine PDGF-dependent fibroblast proliferation at the level of the PDGF alpha receptor. Initially, I will study the effects of a 50% reduction in the PDGF alpha receptor by comparing fibroblast proliferation in response to asbestos and growth factors in vitro, and lung scar development following aerosolized asbestos exposure in vivo , between normal C-57 and C-57 """"""""patch"""""""" mice (""""""""patch"""""""" mice express 50% fewer PDGF alpha receptors in smooth muscle cells than normal C-57 mice). Finally, I will confirm the significance of the PDGF-dependent autocrine fibroblast proliferation in vitro using a dominant negative PDGF alpha receptor mutant. The proposed experiments will enhance our understanding of the role of PDGF in fibroproliferative lung disease.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Clinical Investigator Award (CIA) (K08)
Project #
1K08HL003374-01
Application #
2211616
Study Section
Research Training Review Committee (RTR)
Project Start
1995-09-01
Project End
1999-08-31
Budget Start
1995-09-01
Budget End
1996-08-31
Support Year
1
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Tulane University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
City
New Orleans
State
LA
Country
United States
Zip Code
70118
Ortiz, Luis A; Champion, Hunter C; Lasky, Joseph A et al. (2002) Enalapril protects mice from pulmonary hypertension by inhibiting TNF-mediated activation of NF-kappaB and AP-1. Am J Physiol Lung Cell Mol Physiol 282:L1209-21
Ortiz, L A; Lasky, J; Gozal, E et al. (2001) Tumor necrosis factor receptor deficiency alters matrix metalloproteinase 13/tissue inhibitor of metalloproteinase 1 expression in murine silicosis. Am J Respir Crit Care Med 163:244-52
Lasky, J A; Brody, A R (2000) Interstitial fibrosis and growth factors. Environ Health Perspect 108 Suppl 4:751-62
Ortiz, L A; Lasky, J A; Safah, H et al. (1999) Exacerbation of bleomycin-induced lung injury in mice by amifostine. Am J Physiol 277:L1239-44
Ortiz, L A; Lasky, J; Lungarella, G et al. (1999) Upregulation of the p75 but not the p55 TNF-alpha receptor mRNA after silica and bleomycin exposure and protection from lung injury in double receptor knockout mice. Am J Respir Cell Mol Biol 20:825-33
Hagood, J S; Miller, P J; Lasky, J A et al. (1999) Differential expression of platelet-derived growth factor-alpha receptor by Thy-1(-) and Thy-1(+) lung fibroblasts. Am J Physiol 277:L218-24
Lasky, J A; Tonthat, B; Liu, J Y et al. (1998) Upregulation of the PDGF-alpha receptor precedes asbestos-induced lung fibrosis in rats. Am J Respir Crit Care Med 157:1652-7
Lasky, J A; Ortiz, L A; Tonthat, B et al. (1998) Connective tissue growth factor mRNA expression is upregulated in bleomycin-induced lung fibrosis. Am J Physiol 275:L365-71
Liu, J Y; Morris, G F; Lei, W H et al. (1997) Rapid activation of PDGF-A and -B expression at sites of lung injury in asbestos-exposed rats. Am J Respir Cell Mol Biol 17:129-40
Lasky, J A; Bonner, J C; Tonthat, B et al. (1996) Chrysotile asbestos induces PDGF-A chain-dependent proliferation in human and rat lung fibroblasts in vitro. Chest 109:26S-28S

Showing the most recent 10 out of 18 publications