A novel role of an old friend: Cellular glutathione protects cells from formaldehyde toxicity

AGUSTÍN MORELLATO; MARCO SCHEIDEGGER; CARLA UMANSKY; MANUELA MARTINEFSKY; GABRIELA FERNANDÉZ; MARIELA BOLLINI; MARIA EUGENIA MONGE; LUCAS PONTEL

Congreso; Reunión Anual de Sociedades de Biosciencias SAIC SAF SAFIS; 2020

As a byproduct of certain biological processes, reactive metabolites such as formaldehyde (FA) are produced inside cells, and need to be metabolized to limit their toxicity. Previously we demonstrated that human colorectal carcinoma cells lacking the FA-metabolizing enzyme alcohol dehydrogenase 5 (ADH5) cannot cope with blood concentrations of FA, which can be reverted by thiol-containing antioxidants like N-acetylcysteine (NAC) or glutathione monoethyl ester (GSH-MEE). The rescue of FA toxicity by thiol-rich antioxidants might indicate that the major intracellular thiol-rich antioxidant glutathione (GSH) participates in limiting the toxicity of endogenous FA. To address this hypothesis, we set out to inactivate the gene coding for the regulatory unit (GCLM) of the enzyme γ-glutamatecysteine ligase (GCL), which conforms the GSH synthesis pathway, by CRISPR/Cas9 in HCT116 human colorectal carcinoma cells. The formaldehyde LC50s were WT = 174.0±8.7µM; ∆ADH5 = 83.9±8.7µM; ΔGCLM= 142.1±6.8µM (n=5, mean ± SEM). Moreover, the plating efficiency in presence of 25 µM FA compared to untreated was WT = 90.1±6.3 %; ∆ADH5 = 7.9±2.7 % (P