The goal of this research is to elucidate the regulation of expression of proteinase-3 (PR-3) and its potential role in the lung matrix destruction occurring in pulmonary emphysema. BACKGROUND: Emphysema is an important medical problem associated with excessive morbidity and mortality. However, the pathobiochemical mechanisms which lead to the development of emphysema are not fully understood. It appears that lung matrix destruction by proteinases is central to the pathogenesis of emphysema. Phagocytes which are strategically located in the lungs of cigarette smokers at the site of the earliest emphysematous lesions are the likely source of the proteinases. Our laboratory has identified a novel serine proteinase in human polymorphonuclear leukocytes PR-3, which causes experimental emphysema. In order to gain further insight into the potential role of PR-3 in emphysema, we propose experiments to elucidate the properties of PR-3 that account for its emphysema producing potential. RESEARCH PLAN: We will use a multidisciplinary approach to address the stated specific aims:
The first aim i s to determine the structure of the PR-3 gene and characterize its regulatory elements. We will determine the nucleotide sequence and organization of the gene and the adjacent 5' and 3' regions and define cis-acting DNA elements that may determine the tissue expression and developmental specific expression of the gene. The second specific aim of this proposal is to define the mechanisms that regulate PR-3 expression in myeloid precursors. Using in situ hybridization, we will determine the period during myelomonocytic development when the gene is active. The mechanisms of transcriptional and post transcriptional regulation in myeloid precursors will be studied using chemical inducers and growth factors. The biosynthesis and processing of PR-3 in myeloid cells will be characterized. The third specific aim of this proposal is to determine the functional properties of PR-3 that account for its emphysema producing potential. We will develop a stable expression system to produce a recombinant form of PR-3 which has biologic activity. We will further characterize its role in matrix degradation and cell migration, and its interaction with proteinase inhibitors. SIGNIFICANCE: The proposed research will provide a better understanding of the potential role of PR-3 in the lung matrix destruction occurring in emphysema and other pulmonary disorders. It may lead to new strategies for controlling the expression of PR-3 and other serine proteinases in the lung.
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