Lead and Ethanol exposure reduces mitochondrial respiration in neuroblastoma SH-SY5Y cells. Role of Aldehyde dehydrogenase 2 activity

Congreso; 5° Congreso Anual SAN: Sociedad Argentina de Investigación en Neurociencias; 2020

Sociedad Argentina de Investigación en Neurociencias

Clinical 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. ALDH2 is a mitochondrial oxidoreductase which metabolizes ACD to acetate during EtOH metabolism. Increasing evidence has revealed a protective function of ALDH2 due to its role in detoxification pathways including dopamine metabolism. Based on a reduced brain mitochondrial aldehyde dehydrogenase 2 ALDH2 activity and expression observed in the Pb-exposed rats, in vitro experiments were performed in neuroblastoma SH-SY5Y cells, aimed to elucidate the mechanisms that modulate ALDH2 function and ACD toxicity in the presence of Pb and EtOH in the mitochondrial function. Thus, neuroblastoma cells were exposed to Pb (10µM), EtOH (200 mM) or Pb plus EtOH (10µM/200mM) for 24 h. Then, whole intact cells (1x106 per chamber) were analized in an Oxygraph Oroboros 2K for oxygen consumption rates. Initially, basal respiration (Routine) was assessed and then mitochondrial chain inhibitors were used: Oligomycin (Leak), FCCP (maximal capacity), Rotenone and Antimycin A (non-mitochondrial respiration). The results resembled the in vivo data showing that Pb, EtOH and their combination inhibited ALDH2 activity in SH-SY5Y cells. High-resolution respirometry shows that after Pb/EtOH exposure, routine and maximal respiratory capacity were decreased. Also, the respiratory reserve capacity was reduced by Pb and Ethanol.In conclusion, Pb and EtOH exposure causes mitochondrial toxicity altering bioenergetics in SH-SY5Y cells and decreases ALDH2 activity. Given the neuroprotective function of ALDH2, these alterations could be driven by an ACD (and other toxic aldehydes) accumulation into the cell leading to a bioenergetics impairment. Further experiments are focused on increase ALDH2 activity in order to restore the mitochondrial function in SH-SY5Y cells exposed to Pb and EtOH