Cholesterol Enhances the Toxic Effect of Ethanol and Acetaldehyde in Primary Mouse Hepatocytes

Abstract

Obesity and alcohol consumption are risk factors for hepatic steatosis, and both commonly coexist. Our objective was to evaluate the effect of ethanol and acetaldehyde on primary hepatocytes obtained from mice fed for two days with a high cholesterol (HC) diet. HC hepatocytes increased lipid and cholesterol content. HC diet sensitized hepatocytes to the toxic effect of ethanol and acetaldehyde. Cyp2E1 content increased with HC diet, as well as in those treated with ethanol or acetaldehyde, while the activity of this enzyme determined in microsomes increased in the HC and in all ethanol treated hepatocytes, HC and CW. Oxidized proteins were increased in the HC cultures treated or not with the toxins. Transmission electron microscopy showed endoplasmic reticulum (ER) stress and megamitochondria in hepatocytes treated with ethanol as in HC and the ethanol HC treated hepatocytes. ER stress determined by PERK content was increased in ethanol treated hepatocytes from HC mice and CW. Nuclear translocation of ATF6 was observed in HC hepatocytes treated with ethanol, results that indicate that lipids overload and ethanol treatment favor ER stress. Oxidative stress, ER stress, and mitochondrial damage underlie potential mechanisms for increased damage in steatotic hepatocyte treated with ethanol.

Gamma‐Tocotrienol Attenuates the Hepatic Inflammation and Fibrosis by Suppressing Endoplasmic Reticulum Stress in Mice

“…ER stress is a well‐known contributing factor that augments DNL and precipitates simple steatosis to fibrosis . Numerous evidence suggests that inclusion of fructose and cholesterol in diet instigates hepatic ER stress and NF‐κB activation . It was not surprising that γT3 is capable of suppressing hepatic ER stress against HFCS diet (Figure B), as γT3 alleviates the hepatic TG content (Figure B).…”

Oxidative stress caused by a SOD1 deficiency ameliorates thioacetamide-triggered cell death via CYP2E1 inhibition but stimulates liver steatosis

“…Protein concentrations were determined using a Pierce ® BCA™ Protein Assay Kit (Pierce). The following antibodies were used: SOD1 (Iuchi et al 2007), SOD2 (Iuchi et al 2007), GPx1 (Fujii et al 2002), Prx1 (Ishii et al 2005 Assay of CYP2E1 activity CYP2E1 activity was measured by the rate of oxidation of p-nitrophenol to p-nitrocatechol, as described previously (López-Islas et al 2016) with minor modifications. Briefly, a mixture containing 100 mM potassium phosphate buffer pH 7.4, 200 μM p-nitrophenol, 1 mM NADPH, was incubated with liver lysate (200 µg protein) at 37 °C for 60 min in the dark, and the reaction was terminated by adding 20 % trichloroacetic acid to the suspension.…”

Dihydroartemisinin attenuates alcoholic fatty liver through regulation of lipin‐1 signaling

“…Disruption of lipin‐1 signaling by lipin‐1β overexpression adenovirus vector cancelled the effect of DHA. In spite of lack of a complete understanding of the molecular mechanisms underlying alcohol‐induced hepatocyte apoptosis, mitochondrial dysfunction has been found to participate in the mechanisms . Our recent study reported that mitochondrial dysfunction induced by lipotoxicity contributes to alcohol‐induced hepatocyte injury .…”

“…Hepatocyte cell death triggered by lipotoxicity, is also called lipoapoptosis . Accumulating evidence demonstrates that oxidative stress and endoplasmic reticulum (ER) stress are the major intracellular pathways mechanistically involved in lipoapoptosis . Ethanol can also promote hepatic lipid accumulation and inflammation by activating the ER stress response.…”