THE EXPRESSION OF THE RARE CAVEOLIN-3 VARIANT T78M ALTERS CARDIAC ION CHANNELS FUNCTION AND MEMBRANE EXCITABILITY.

The identification of new molecular insights always drove the research. Data from genetic, molecular biology and biochemistry suggest new directions, open new fields and lead to new discoveries. The significance of these data is, in certain situation, difficult to envision. In this view, physiology could represent one of the possible read-out of the overall complex modifications inside the cell. In particular, electrophysiological analysis shed light on both physiological and pathological conditions in excitable and non-excitable cells. In excitable cell, ion channels, cellular microenvironment, transcription factors and accessory proteins shape the electric profile of the cell. In my PhD, I mainly used this approach to test the effect of mutations associated with arrhythmic diseases (in both cardiac arrhythmia and epilepsy) and of physiopathological remodeling in response to endurance training. In particular, I performed the following projects concerning: - Characterization of the biophysical properties of the hHCN1 L157V mutation found in a patient affected by idiopathic generalized epilepsy. This mutation resulted to decrease the current density and leading to an increased excitability in single neonatal rat cortical neurons. - Analysis of the cardiac endurance training-associated microRNAs (miRNAs) in a trained mouse model and of the role of the muscle-specific miRNAs in modulating membrane excitability in the neonatal rat ventricular cardiomyocytes. These results highlights new miRNAs potentially involved in the cardiac electrical remodeling associated with endurance training. - Characterization of the impact of the T78M cav-3 variant found in a cohort of arrhythmic patients. This variant induces modification of several ionic currents leading to a pro-arrhythmogenic profile. The leitmotiv of these projects is the identification of the causes underlying the pathophysiological modification of excitable cells by ion channels, membrane proteins and post-transcriptional molecules.