OVEREXPRESSION OF MITOCHONDRIAL NHE1 ALTERS MITOCHONDRIAL MEMBRANE POTENTIAL AND MATRIX pH REGULATION

DE FAZIO R; CIANCIO MC; ORLOWSKI A; AIELLO EA; JAQUENOD DE GUISTI C

Mendoza

Congreso; 2023 Annual Congress of ISHR Latin American section; 2023

Mitochondria are not only implicated in energy production but also in pathological events. Mitochondrial dysfunction has been related to the development of several pathologies including heart failure and diabetes. The Na+/H+ exchanger 1 (NHE1) is one of the main alkalinizing mechanisms in the heart and its hyperactivity has been observed in several heart conditions, including diabetic cardiomyopathy. In obese and diabetic mice mitochondrial NHE1 expression is increased despite similar cardiac levels, together with altered calcium handling, which are reverted in the presence of an NHE1 inhibitor. Aim: understanding the consequences of increased mitochondrial NHE1 expression. Materials and methods: HEK293T cells were transfected with a mitochondrial-targeted NHE1 expression vector (pmitoNHE1). Mitochondrial membrane potential was expressed as JC-1 aggregate/monomer fluorescence. Mitochondrial pH was measured using a mitochondrial-targeted pH sensor. Mitochondrial ROS production was measured using the H2DCFDA indicator. Data are expressed as means ± SEM and are compared with Student's t-test.Results: Mitochondrial NHE1 overexpression resulted in increased mitochondrial membrane potential, similar to our observations in obese and diabetic heart mitochondria (0.6140 in control vs 0.7561 in pmitoNHE1 cells, p