DESIGN OF MUTATIONS IN TISSUE PLASINOGEN ACTIVATOR

TISSUE PLASMINOGEN ACTIVATOR (TPA) IS A THROMBOLYTIC AGENT THAT HAS BEEN DEMONSTRATED TO BE EFFICACIOUS FOR CLOTS THAT CAUSE MYOCARDIAL INFARCTION AND PULMONARY EMBOLISM. THE AGENT, HOWEVER, MUST BE ADMINISTERED AT HIGH DOSES OVER SEVERAL HOURS. MAJOR AND MINOR BLEEDING MAY OCCUR IN PATIENTS TREATED WITH TPA. THESE COMPLICATIONS PRECLUDE ITS USE IN THE LARGE CARDIOVASCULAR-DISEASE PATIENT POPULATION WITH CONTRAINDICATIONS SUCH AS PREVIOUS STROKE OR PREVIOUS MYOCARDIAL INFARCTION. THE LONG-TERM OBJECTIVE IS TO GENERATE A SECOND-GENERATION TPA BY PROTEIN-ENGINEERING TECHNIQUES THAT HAS SUBSTANTIALLYHIGHER EFFICACY IN CLOT LYSIS. THIS MAY HIELD AN AGENT THATCAN BE ADMINISTERED IN SMALLER DOSES AND WITH FEWER BLEEDING COMPLICATIONS. FIBRIN AFFINITY HAS BEEN IDENTIFIED AS A PROPERTY THAT CAN BE IMPROVED AND WOULD CONTRIBUTE TO HIGHER EFFICACY IN CLOT LYSIS. PHASE I OF THIS PROJECT IS A MOLECULAR-MODELING STUDY OF THE KRINGLE REGIONS OF TPA WHERE AMINO ACID RESIDUES THAT CAN BE MODIFIED TO INCREASE THE BINDING AFFINITY OF FIBRIN ANALOGS WILL BE IDENTIFIED. IN PHASE II, INTEGRATED GENETICS, INC., WILL GENERATE AND TEST THESE MOLECULES IN VIVO.