The overall goals of this proposal is to devise practical and novel means for treating the lung disease of cystic fibrosis (CF). Since unanswered questions about the pathophysiology and pathogenesis of lung disease prevent strategic therapeutic designs, Projects 1-4 will seek relevant basic information. In Project 1, Ulrich Hopfer will determine the relation between chloride transport and macromolecular secretion. He showed that chloride transporters in the membranes of secretory granules can be activated by hormonal stimulation in vivo. He will pursue these observations in human cells. Alan Tartakoff (Project 2) will test the hypothesis that some CFTR mutants are abnormally processed and degraded in the endoplasmic reticulum. He will capitalize on the availability of yeast mutants for protein processing and degradation to pinpoint the site(s) of defective processing and degradation of CFTR, clone the genes responsible, search for human homologs, and apply his findings to airway cells. These two projects address the important issue of the relative importance of defective chloride transport and processing of mutant CFTR in CF pathogenesis. Some proposed therapies for CF aim at activating alternative pathways for chloride secretion in airway epithelia. To sustain transport, chloride must enter the cell at the basolateral membrane, probably by the Na/K/2Cl cotransporter. In Project 3, Carole Liedtke and Mark Kester will study its regulation by protein kinase C. Their findings on the isoforms and activators of protein kinase C in airway cells will also be used in designing strategies to maximally activate mutant CFTR. In Project 4, Mitchell Drumm will determine whether CFTR mutants can be made to arrive at the plasma membrane in human airway and intestinal epithelial cells and whether they can be activated there, as he has shown they can in Xenopus oocytes. This projects 4-6 address therapeutics. Projects 5 and 6 deal with controlling the exuberant inflammatory response in the CF lung, which is the agent of the lung destruction. In Project 5, Michael Tosi will investigate the utility of blockade of cell adhesion molecules in endothelium and epithelium for limiting the inflammatory response, using a mouse model of chronic pseudomonas infection as well as a human cell culture model. In Project 6 Melvin Berger will investigate the mechanisms of action of intravenous immune globulin, shown to be beneficial in acute exacerbations, in CF lung disease. Berger will test the novel hypothesis that the mechanism of action is not only through specific antipseudomonas antibodies but through antibodies to lipopolysaccharide which limit the cytokine responses of macrophages and damp the inflammatory vicious cycle. These projects will be supported by administrative, monoclonal antibody, and cell physiology cores. Taken together, the information derived from these projects will have important implications for therapeutic strategies for the CF lung disease.
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