Lead and Ethanol exposure reduces mitochondrial respiration in neuroblastoma SH-SY5Y cells. Impact on aldehyde dehydrogenase 2 functionality

DEZA PONZIO ROMINA; EICHWALD TUANY; ALBRECHT, PAULA A.; FERNANDEZ HUBEID, LUCIA; CANCELA LILIANA M; IRAZOQUI F; LATINI A; VIRGOLINI MB,

Congreso; XXXV Congreso Anual SAN 2020. Córdoba, Argentina (modalidad virtual); 2020

Lead and Ethanol exposure reduces mitochondrial respiration in neuroblastoma SH-SY5Y cells. Impact on aldehyde dehydrogenase 2 functionality.Romina Deza-Ponzio1, Tuany Eichwald3, Paula A. Albrecht1, Lucía E. Fernandez-Hubeid1, Liliana M. Cancela1, Fernando J. Irazoqui2, Alexandra Latini3 and Miriam B. Virgolini1.1IFEC-CONICET. Departamento de Farmacología. Facultad de Ciencias Químicas. Universidad Nacional de Córdoba, Córdoba, Argentina 2CIQUIBIC-CONICET. Departamento de Química Biológica. Facultad de Ciencias Químicas. Universidad Nacional de Córdoba, Córdoba, Argentina 3Departamento de Bioquímica, Centro de Ciencias Biológica, Universidad Federal de Santa Catarina, SC, Brasil. rdezaponzio@fcq.unc.edu.arClinical and experimental evidences in laboratory animals demonstrate that the neurotoxicant lead (Pb) induces neurobehavioral alterations, including an altered response to drugs. We have previously reported that perinatally-Pb-exposed rats showed elevated ethanol (EtOH) intake, which seems to be mediated by brain acetaldehyde (ACD) accumulation. Aldehyde dehydrogenase 2 (ALDH2) is a mitochondrial oxidoreductase that metabolizes ACD to acetate during EtOH metabolism, with NAD+ consumption as the limiting factor of the reaction. Based on a reduced brain mitochondrial ALDH2 activity and expression observed in the Pb-exposed rats, in vitro experiments were performed in neuroblastoma SH-SY5Y cells to elucidate the mechanisms that modulate ALDH2 function in the presence of Pb and EtOH. Importantly, ALDH2 cofactor NAD+ is reoxidized in the mitochondria. Thus, whole intact neuroblastoma cells (1x106 per chamber) were exposed to Pb (10µM), EtOH (200 mM) or Pb plus EtOH (10µM/200mM) for 24 h and thereafter analyzed in an Oxygraph Oroboros 2K for oxygen consumption rates. Initially, basal respiration (Routine) was assessed followed by mitochondrial chain inhibitors: Oligomycin (Leak), FCCP (maximal capacity), Rotenone and Antimycin A (non-mitochondrial respiration). The results replicated the in vivo data in terms of ALDH2 inhibition after Pb, EtOH or the combination treatment in SH-SY5Y cells. High-resolution respirometry shows that Pb and EtOH exposure decreased routine and maximal respiratory capacity as well as the respiratory reserve capacity.It can be concluded that Pb and EtOH exposure causes mitochondrial toxicity by altering bioenergetics in SH-SY5Y cells, with possible consequences on NAD+ availability and thereby ALDH2 functionality. Further experiments are focused on restoring ALDH2 activity in SH-SY5Y cells exposed to Pb and EtOH by the cofactor supplementation or by the treatment with an ALDH activator.Funded by: MinCyT, CONICET and SeCyT-UNC, Argentina.