Project Grant R21EY036216

STEROL BIOSYNTHESIS INHIBITORS AS DRUG LEADS FOR THE TREATMENT OF ACANTHAMOEBA EYE INFECTION - PROJECT SUMMARY/ABSTRACT ACANTHAMOEBA KERATITIS (AK) CAN OCCUR IN HEALTHY INDIVIDUALS WEARING CONTACT LENSES AND IT IS A PAINFUL BLINDING INFECTION OF THE CORNEA CAUSED BY A FREE-LIVING AMEBA ACANTHAMOEBA. COMPLICATIONS INCLUDE CHRONIC OCULAR INFLAMMATION, CORNEAL MELTING AND SCARRING. CURRENT TREATMENT FOR AK RELIES ON A COMBINATION OF CHLORHEXIDINE, PROPAMIDINE ISETHIONATE, AND POLYHEXAMETHYLENE BIGUANIDE. HOWEVER, IN 10% OF CASES RECURRENT INFECTION ENSUES, BECAUSE OF THE DIFFICULTY IN KILLING BOTH TROPHOZOITES AND DOUBLE-WALLED CYSTS. THEREFORE, DEVELOPMENT OF EFFICIENT AND SAFE DRUGS IS A CRITICAL UNMET NEED TO AVERT BLINDNESS. BECAUSE AK IS A RARE DISEASE, THERE IS A PAUCITY OF DRUG DISCOVERY EFFORTS BY THE PHARMACEUTICAL INDUSTRY AND DRUG DISCOVERY FOR THIS INFECTION LARGELY RELIES ON ACADEMIC RESEARCH CENTERS. TO REDUCE THE COST, TIME AND RISK ASSOCIATED WITH THE DEVELOPMENT OF NEW AK THERAPIES, WE FOCUSED ON REPURPOSING OF THE FDA-APPROVED STEROL BIOSYNTHESIS INHIBITORS PITAVASTATIN AND ISAVUCONAZONIUM FOR THE TREATMENT OF AK. IDENTIFICATION OF HMG-COA REDUCTASE (HMGR) INHIBITORS AND STEROL 14-DEMETHYLASE (CYP51) INHIBITORS, WHICH ARE AMEBICIDAL, AND COMBINATION OF NOVEL CYSTICIDAL ASSAY WITH PHENOTYPIC TROPHOZOITE SCREEN LAID THE FOUNDATION FOR THIS PROPOSAL. WE HAVE GENERATED SIGNIFICANT DATA SHOWING THAT (1) PITAVASTATIN AND ISAVUCONAZONIUM ARE POTENT TROPHOCIDALS AGAINST THREE CLINICAL STRAINS OF A. CASTELLANII, (2) ISAVUCONAZONIUM SULFATE AND ITS MAJOR METABOLITE ISAVUCONAZOLE EXHIBIT LOW NANOMOLAR POTENCY AGAINST TROPHOZOITES, (3) BOTH ISAVUCONAZONIUM AND ISAVUCONAZOLE SUPPRESS EXCYSTMENT OF CYSTS INTO TROPHOZOITES, (4) COMBINATION OF PITAVASTATIN AND ISAVUCONAZOLE IS SYNERGISTIC ON TROPHOZOITES, AND (5) ISAVUCONAZOLE TARGETS A. CASTELLANII CYP51 AND PARASITE HMGR MAY BE A RELEVANT TARGET FOR PITAVASTATIN. BASED ON THESE RESULTS, WE PROPOSE TO 1) EVALUATE MAMMALIAN CYTOTOXICITY AND TROPHOCIDAL AND CYSTICIDAL ACTIVITIES OF COMBINATION OF PITAVASTATIN AND FDA-APPROVED FORM ISAVUCONAZONIUM AND COMPARE THAT WITH THE EFFECT OF PITAVASTATIN AND ISAVUCONAZONIUM ALONE, 2) CONDUCT TOLERABILITY AND PHARMACOKINETIC- PHARMACODYNAMIC STUDIES OF TOPICALLY ADMINISTERED PITAVASTATIN AND ISAVUCONAZONIUM, BOTH MONOTHERAPY AND IN COMBINATION THERAPY AND 3) TEST IN VIVO EFFICACY OF TOPICAL PITAVASTATIN AND ISAVUCONAZONIUM, ALONE AND IN COMBINATION WITH EACH OTHER, IN AN ANIMAL MODEL OF AK CAUSED BY ACANTHAMOEBA OF TWO DIFFERENT GENOTYPES. THIS STUDY IS A NECESSARY STEP TOWARD REPURPOSING OF TOPICALLY ADMINISTERED PITAVASTATIN AND ISAVUCONAZONIUM FOR THE TREATMENT OF AK. TO SUCCESSFULLY ACHIEVE THE PROPOSAL GOALS, WE RELY ON OUR EXISTING COLLABORATION THAT COMBINES THE UNIQUE EXPERTISE OF DR. DEBNATH (PI) IN ACANTHAMOEBA PARASITE BIOLOGY AND DR. AFSHARI IN OPHTHALMOLOGY. DRS. DEBNATH AND AFSHARI'S EXPERTISE AND EXPERIENCE IN PARASITIC EYE INFECTION HAS POTENTIAL TO ELEVATE OUR DRUG REPURPOSING PLATFORM TO A TRANSLATIONAL LEVEL.