Proteolysis of lung extracellular matrix during inflammation is a pivotal event in pathogenesis of pulmonary emphysema and other disabling lung diseases. We have several lines of preliminary evidence which indicate that catalytic activity of human leukocyte elastase (HLE) and cathepsin G (CG) is focused at the cell surface of human polymorphonuclear neutrophils, even in an inhibitor-rich environment such as exists in the extracellular space in vivo. Our working hypothesis is that active cell- surface-bound proteinases on inflammatory cells are brought into contact with potential matrix substrates by specific adherence molecules, permitting the cells to penetrate tissue barriers and creating the potential for matrix injury. Moreover, recent evidence indicates that another serine proteinase of neutrophils (proteinase 3; PR3) is the antigen recognized by one class of """"""""anti-neutrophil cytoplasmic antibodies"""""""" (ANCA) in individuals with Wegener's granulomatosis. Our working hypothesis is that when PR3 is expressed on the cell surface of neutrophils and mononuclear phagocytes, it becomes the primary target of the autoimmune process. Ensuing cellular events then both activate and attract inflammatory cells, leading to a vicious cycle which culminates in necrotizing vasculitis. We will address the following Specific Aims. 1) Study of serine proteinases (HLE, CG, and PR3) bound to the cell surface of human neutrophils and monocytes, with regard to: a) quantification on resting and stimulated cells; b) catalytic activity and resistance to inhibition; c) mechanism(s) of binding to the cell surface; and d) inflammatory cell activation by autoantibodies. 2) Study of proteolysis in zones of close contact between cells and subjacent substrates, with regard to: a) co- distribution of cell-surface-bound serine proteinases and selected adherence molecules on polarized cells; and b) importance of adhesion patches in permitting inhibitor-resistant proteolysis. Inflammatory cells both degrade biologically important matrix proteins in vivo and also provide excellent models for study of inhibitor-resistant matrix proteolysis in vitro. We anticipate that the proposed studies of serine proteinase activity at the cell surface will provide insights into mechanisms of tightly controlled extracellular proteolytic activity occurring at the cell surface, as well as into potential basic mechanisms of tissue injury during inflammation.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL046440-04
Application #
2222921
Study Section
Pathology A Study Section (PTHA)
Project Start
1991-05-01
Project End
1995-11-30
Budget Start
1994-05-01
Budget End
1995-11-30
Support Year
4
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of Utah
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
City
Salt Lake City
State
UT
Country
United States
Zip Code
84112
Silverman, Edwin K; Mosley, Jonathan D; Palmer, Lyle J et al. (2002) Genome-wide linkage analysis of severe, early-onset chronic obstructive pulmonary disease: airflow obstruction and chronic bronchitis phenotypes. Hum Mol Genet 11:623-32
Silverman, Edwin K; Palmer, Lyle J; Mosley, Jonathan D et al. (2002) Genomewide linkage analysis of quantitative spirometric phenotypes in severe early-onset chronic obstructive pulmonary disease. Am J Hum Genet 70:1229-39
Wencker, M; Marx, A; Konietzko, N et al. (2002) Screening for alpha1-Pi deficiency in patients with lung diseases. Eur Respir J 20:319-24
Silverman, E K; Mosley, J D; Rao, D C et al. (2001) Linkage analysis of alpha 1-antitrypsin deficiency: lessons for complex diseases. Hum Hered 52:223-32
Campbell, E J; Campbell, M A; Owen, C A (2000) Bioactive proteinase 3 on the cell surface of human neutrophils: quantification, catalytic activity, and susceptibility to inhibition. J Immunol 165:3366-74
Campbell, E J (2000) Animal models of emphysema: the next generations. J Clin Invest 106:1445-6
Morrison, H M; Welgus, H G; Owen, C A et al. (1999) Interaction between leukocyte elastase and elastin: quantitative and catalytic analyses. Biochim Biophys Acta 1430:179-90
Campbell, E J; Campbell, M A; Boukedes, S S et al. (1999) Quantum proteolysis by neutrophils: implications for pulmonary emphysema in alpha 1-antitrypsin deficiency. J Clin Invest 104:337-44
Owen, C A; Campbell, E J (1999) The cell biology of leukocyte-mediated proteolysis. J Leukoc Biol 65:137-50
Owen, C A; Campbell, E J (1999) Extracellular proteolysis: new paradigms for an old paradox. J Lab Clin Med 134:341-51

Showing the most recent 10 out of 27 publications