Project Grant F31HL188870

USING A HEART-LIKE YEAST MODEL TO INVESTIGATE THE BENEFIT OF CARDIOLIPIN REMODELING. - PROJECT SUMMARY CARDIOLIPIN (CL) IS A MITOCHONDRIA-SPECIFIC PHOSPHOLIPID ESSENTIAL FOR MAINTAINING OXIDATIVE PHOSPHORYLATION (OXPHOS) BY STABILIZING RESPIRATORY CHAIN COMPLEXES AND SUPERCOMPLEXES. NEWLY SYNTHESIZED CL UNDERGOES MULTIPLE PROCESSING STEPS BEFORE REACHING ITS MATURE FORM. IN MAMMALIAN CARDIAC MUSCLE TISSUE, MATURE CL IS ENRICHED IN POLYUNSATURATED CARDIOLIPIN (PUFA-CL), WHEREAS YEAST LACK POLYUNSATURATED FATTY ACIDS AND INSTEAD INCORPORATE MONO-UNSATURATED ACYL CHAINS INTO CL. DESPITE THE PERVASIVENESS OF PUFA-CL, THE PHYSIOLOGICAL ADVANTAGE OF REMODELING TO THIS FORM REMAINS UNCLEAR. UNDERSTANDING THESE MECHANISMS WILL PROVIDE INSIGHT INTO MITOCHONDRIAL BIOENERGETICS AND CARDIOVASCULAR DISEASE ASSOCIATED WITH PERTURBED CL METABOLISM. HERE, WE GENERATE YEAST WITH A CL PROFILE RESEMBLING MAMMALIAN CARDIAC MUSCLE TO INVESTIGATE HOW CL ACYL CHAIN COMPOSITION INFLUENCES MITOCHONDRIAL FUNCTION. HERE WE DEMONSTRATE INTRODUCTION OF PUFA RICH MEMBRANES ALTERED RESPIRATION, ENHANCING ADP-STIMULATED ACTIVITY BUT IMPAIRING COMPLEX IV FUNCTION. WE WILL (1) ASSESS WHETHER PUFA-CL PROMOTES RESPIRATORY PROTEIN EXPRESSION, ASSEMBLY, AND/OR STABILITY; (2) DETERMINE IF PUFA-CL DIFFERENTIALLY AFFECTS THE ACTIVITY OF INDIVIDUAL RESPIRATORY COMPLEXES VERSUS ASSEMBLED SUPERCOMPLEXES; AND (3) TEST HOW PUFA-CL REMODELING INFLUENCES MITOCHONDRIAL RESILIENCE UNDER VARYING OXIDATIVE AND METABOLIC STRESS USING GENETIC PERTURBATIONS, BIOCHEMICAL ASSAYS, AND OXYGEN CONSUMPTION MEASUREMENTS. THESE STUDIES WILL HELP DEFINE HOW CARDIOLIPIN REMODELING SHAPES MITOCHONDRIAL ENERGY METABOLISM AND STRESS TOLERANCE. OUTCOMES WILL ADVANCE MECHANISTIC UNDERSTANDING OF MITOCHONDRIAL PHOSPHOLIPID BIOLOGY AND ESTABLISH NEW CONCEPTUAL FRAMEWORKS FOR CL-DEPENDENT HEART DISEASES.