Protective potential of glutathione peroxidase‐1 gene against cocaine‐induced acute hepatotoxic consequences in mice

Abstract

Since the cocaine-induced oxidative stress has been established to lead to hepatotoxicity, we examined the role of the glutathione peroxidase (GPx)-1 gene in cocaine-induced hepatotoxicity. Cocaine treatment significantly increased superoxide dismutase activity in as little as 1 hour, with a maximum level at 6 hours in wild-type mice, while significantly decreasing GPx activity and subsequently inducing oxidative damage (i.e., reactive oxygen species, lipid peroxidation and protein carbonylation). These changes were more prominent in the mitochondrial fraction than in the cytosolic fraction. In contrast, genetic overexpression of GPx-1 significantly attenuated cocaine-induced oxidative damage in mice. Cocaine treatment significantly increased alanine aminotransferase and aspartate aminotransferase levels in the serum. Consistently, cocaine significantly enhanced cleaved caspase-3 expression and intramitochondrial Ca , while significantly reducing mitochondrial transmembrane potential. Cocaine treatment potentiated cleavage of protein kinase C δ (PKCδ), mitochondrial translocation of PKCδ, cytosolic release of cytochrome c and activation of caspase-3, followed by hepatopathologic changes. These results were more prominent in GPx-1 knockout than in wild-type mice, and they were less pronounced in overexpressing transgenic than in non-transgenic mice. Combined, our results suggest that the GPx-1 gene possesses protective potential against mitochondrial oxidative burden, mitochondrial dysfunction and hepatic degeneration induced by cocaine and that the protective mechanisms are associated with anti-apoptotic activity via inactivation of PKCδ.

Cocaine: An Updated Overview on Chemistry, Detection, Biokinetics, and Pharmacotoxicological Aspects including Abuse Pattern

“…There were significant increases in SOD activity, ROS, protein carbonylation and lipid peroxidation, cleaved caspase-3 expression and intramitochondrial calcium, accompanied by a significant decrease in GPx. Examples of histological changes include hemorrhage, congestion, periventricular necrosis and hydropic degeneration [124]. Notably, enhanced expression of GPx protected the animals from having such severe outcomes, as did the depletion of p53 [125].…”

Contributing roles of mitochondrial dysfunction and hepatocyte apoptosis in liver diseases through oxidative stress, post-translational modifications, inflammation, and intestinal barrier dysfunction

“…Although the detailed cell death signaling mechanisms are unknown, one recent report showed that cocaine toxicity was attenuated in p53-knockout (p53-KO) mice, suggesting the involvement of the p53-mediated apoptosis pathway [ 295 ]. A recent study showed that cocaine caused mitochondrial dysfunction and acute liver injury in WT mice, and hepatotoxicity was prominently observed in Gpx-1 -KO mice but protected in Gpx1-overexpressing transgenic mice [ 66 ]. Based on the importance of PTMs in mitochondrial dysfunction and hepatocyte cell death in DILI, ALD, and MASLD models, the contributing roles of various PTMs in cocaine-mediated mitochondrial dysfunction and hepatotoxicity are expected, although this needs to be verified by future research.…”

“…The proteins involved in promoting various PTMs exist in several subcellular organelles, including the cytoplasm [ 39 ], ER [ 40 , 41 ], mitochondria [ 42 ], and nucleus [ 43 ]; PTMs may also be observed in the proteomes of the liver [ 37 , 44 – 47 ], gut [ 7 ], and other peripheral tissues [ 29 ]. PTMs found in liver diseases include protein acetylation [ 37 , 42 , 48 ], nitration [ 10 , 26 , 37 , 49 – 53 ], S -nitrosylation [ 49 , 54 , 55 ], oxidation [ 37 ], phosphorylation [ 26 , 56 , 57 ], succinylation [ 58 ], ADP-ribosylation [ 44 ], ubiquitination [ 37 , 59 ], SUMOylation [ 60 – 65 ], carbonylation [ 66 – 68 ], S -palmitoylation [ 45 – 47 , 69 ], glycosylation [ 7 , 37 , 70 , 71 ], protein adducts of aldehyde (i.e., acetaldehydes) [ 9 , 72 ], lipid peroxidation products (LPOs), and advanced glycation end products (AGEs) [ 6 , 66 , 74 – 79 ]. Several studies detail that specific PTMs correlate with exposures to excessive alcohol [ 80 , 81 ], CCl 4 [ 7 , 56 ], acetaminophen (APAP) [ 53 , 82 ], 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy) [ 39 ], or fructose [ 51 ].…”

“…Several studies detail that specific PTMs correlate with exposures to excessive alcohol [ 80 , 81 ], CCl 4 [ 7 , 56 ], acetaminophen (APAP) [ 53 , 82 ], 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy) [ 39 ], or fructose [ 51 ]. In these cases, PTMs accumulate in cells and contribute significantly to fat accumulation [ 54 ], hepatocyte apoptosis, inflammation, fibrosis [ 51 ], and cirrhosis [ 37 ], by altering signaling pathways affiliated with liver disease progression [ 43 , 66 , 67 ] and by targeting proteins for ubiquitin-mediated proteolysis [ 59 ]. Overall, PTMs are one of the various ROS-mediated changes that occur on cellular and translational levels [ 29 ] to, directly and indirectly, contribute to alcohol-mediated hepatic injuries [ 12 , 83 , 84 ].…”

“…Typically, in the second line of defense, mitochondria trigger mitophagy to restore redox homeostasis and retain the function of other mitochondria and organelles for cellular activities [ 101 ]. However, these natural lines of defense in mitochondria can be altered after excessive consumption of or exposure to alcohol (ethanol) [ 85 , 94 ], drugs [ 66 , 102 , 103 ], viruses [ 104 ], and some nutrients, including fructose [ 105 ]. Specifically, these exposures can alter mitochondrial redox homeostasis and oxidatively damage DNA [ 106 , 107 ], RNA [ 106 ], lipids, and proteins, through PTMs [ 8 , 26 , 48 , 70 , 108 , 109 ], causing inactivation of their functions and signaling pathways, leading to mitochondrial dysfunction [ 26 , 53 , 68 , 83 ], death of hepatocytes, and liver damage [ 17 , 110 ] or age-related conditions [ 91 , 111 – 113 ].…”