Project Grant F32AI202597

TRACING THE EVOLUTION OF PATHOGENICITY IN FUNGI - PROJECT SUMMARY/ABSTRACT: FUNGI POSE A SIGNIFICANT THREAT TO HUMAN HEALTH, BUT THE ORIGINS OF THEIR PATHOGENIC POTENTIAL REMAIN AN OPEN QUESTION. THIS PROPOSAL SEEKS TO UNCOVER THE GENETIC DIFFERENCES THAT MAKE SOME FUNGI CAPABLE OF INFECTING HUMANS WHILE OTHERS CANNOT BY FOCUSING ON EVOLUTIONARY DIVERGENCE IN THE CRYPTOCOCCUS LINEAGE, AN IMPORTANT GENUS OF FUNGI COMPRISING BOTH PATHOGENIC AND NONPATHOGENIC SPECIES. SPECIFICALLY, THIS WORK FOCUSES ON INVESTIGATING THE MOLECULAR MECHANISMS BY WHICH SOME SPECIES HAVE EVOLVED THERMOTOLERANCE, AN ESSENTIAL TRAIT WHICH ALLOWS FOR GROWTH AT HUMAN BODY TEMPERATURE. AIM 1 WILL EXPLORE THE EVOLUTIONARY HISTORY OF THERMOTOLERANCE ACROSS CRYPTOCOCCUS SPECIES BY TAKING A COMPARATIVE APPROACH. UTILIZING HIGH-THROUGHPUT SCREENING AND TWO REPRESENTATIVE SPECIES-THE HUMAN PATHOGEN, C. NEOFORMANS AND ITS NONPATHOGENIC, THERMALLY SENSITIVE RELATIVE C. AMYLOLENTUS-THIS AIM WILL REVEAL HOW DIVERGENCE IN SEQUENCE AND FUNCTION IN THERMOTOLERANCE-IMPLICATED GENES CONTRIBUTES TO THE EMERGENCE OF THIS TRAIT. ANCESTRAL SEQUENCE RECONSTRUCTION METHODS WILL FURTHER BE EMPLOYED TO PINPOINT WHEN THERMOTOLERANCE FUNCTIONS EMERGED IN THESE GENES DURING EVOLUTIONARY HISTORY AND TRACE THE SEQUENCE DETERMINANTS THAT FACILITATE THESE EVOLUTIONARY TRANSITIONS. AIM 2 WILL TURN TO THE FUTURE AND PREDICT POTENTIAL AVENUES FOR THE EMERGENCE OF FUNGAL THERMOTOLERANCE USING EXPERIMENTAL EVOLUTION. USING SERIAL PASSAGING OF ENGINEERED HEAT-SENSITIVE STRAINS, THIS APPROACH WILL PROVIDE A DIRECT WINDOW TO OBSERVE HOW THERMOTOLERANCE CAN BE ACQUIRED AND THEN INTERROGATE THE MECHANISMS BEHIND THIS TRANSITION. THIS WILL IDENTIFY UNIQUE CONTRIBUTORS TO HIGH TEMPERATURE GROWTH IN C. NEOFORMANS AND WILL MODEL THE ACQUISITION OF THERMOTOLERANCE IN NON-THERMOTOLERANT ANCESTORS. ALTOGETHER, THIS WORK WILL PROVIDE A SWEEPING VIEW OF THE GENETIC BASIS OF THIS CRITICAL VIRULENCE-ASSOCIATED TRAIT, HOW IT HAS EVOLVED AND HOW IT MAY CONTINUE TO EMERGE IN NEW SPECIES IN THE FUTURE. THIS PROJECT WILL ALSO GENERATE TOOLS AND DATASETS FOR FUTURE STUDIES OF THE EVOLUTION OF OTHER IMPORTANT PATHOGENICITY TRAITS IN THESE SPECIES. THE OVERALL GOAL OF THIS PROJECT IS TO ILLUMINATE THE EVOLUTIONARY AND MOLECULAR MECHANISMS THAT ALLOW SOME FUNGI TO CAUSE HUMAN DISEASE. THIS IN TURN WILL FACILITATE BETTER UNDERSTANDING OF CURRENT FUNGAL INFECTIONS AND GENERATE PREDICTIVE POWER FOR THE EMERGENCE OF NEW HUMAN FUNGAL PATHOGENS. THE UNIQUE, COLLABORATIVE RESEARCH ENVIRONMENT OF BOSTON COLLEGE AND THE COMBINED EXPERTISE OF THE MENTOR/CO-MENTOR TEAM WILL ENSURE THE SUCCESS OF THIS PROJECT, WHILE PROVIDING THE IDEAL TRAINING ENVIRONMENT TO FOSTER THE PI'S PROFESSIONAL AND SCIENTIFIC DEVELOPMENT IN SEVERAL TARGETED AREAS. ULTIMATELY, THE COMBINATION OF THE RESEARCH PROJECT, MENTOR TEAM AND TRAINING ENVIRONMENT WILL CREATE A STRONG FOUNDATION FOR A WELL-DEVELOPED RESEARCH PROGRAM, WHICH WILL ENABLE THE PI TO LAUNCH A SUCCESSFUL CAREER AS AN INDEPENDENT RESEARCHER AND TEACHER.