S-adenosyl-l-methionine protection of acetaminophen mediated oxidative stress and identification of hepatic 4-hydroxynonenal protein adducts by mass spectrometry

Abstract

Acetaminophen (APAP) hepatotoxicity is protected by S-adenosyl-L-methionine (SAMe) treatment 1 hour (h) after APAP in C57/Bl6 mice. This study examined protein carbonylation as well as mitochondrial and cytosolic protein adduction by 4-hydroxynonenal (4-HNE) using mass spectrometry (MS) analysis. Additional studies investigated the leakage of mitochondrial proteins and 4-HNE adduction of these proteins. Male C57/Bl6 mice (n=5/group) were divided into the following groups and treated as indicated: Veh (15 ml/kg water, ip), SAMe (1.25 mmol/kg, ip), APAP (250 mg/kg), and SAMe given 1 h after APAP (S+A). APAP toxicity was confirmed by an increase (p<0.05) in plasma ALT (U/L) and liver weight/10 g body weight relative to the Veh, SAMe and S+A groups 4 h following APAP treatment. SAMe administered 1 h post APAP partially corrected APAP hepatotoxicity as ALT and liver weight/10 g body weights were lower in the S+A group compared the APAP group. APAP induced leakage of the mitochondrial protein, carbamoyl phosphate synthase-1 (CPS-1) into the cytosol and which was reduced in the S+A group. SAMe further reduced the extent of APAP mediated 4-HNE adduction of CPS-1. MS analysis of hepatic and mitochondrial subcellular fractions identified proteins from APAP treated mice. Site specific 4-HNE adducts were identified on mitochondrial proteins sarcosine dehydrogenase and carbamoyl phosphate synthase-1 (CPS-1). In summary, APAP is associated with 4-HNE adduction of proteins as identified by MS analysis and that CPS-1 leakage was greater in APAP treated mice. SAMe reduced the extent of 4-HNE adduction of proteins as well as leakage of CPS-1.

4-Hydroxynonenal (HNE) and hepatic injury related to chronic oxidative stress

“…These processes, in turn, limit the apoptotic potential of HNE [2,20,30]. HNE detoxification by GSTs can be reduced due to depletion of GSH, which in turn may lead to increased levels of HNE [31,32]. On the other hand, S-adenosyl methionine (SAM) diminishes HNE modification of enzymes which have a vital role in the detoxification of HNE [32].…”

New potential biomarkers of acetaminophen-induced hepatotoxicity

“…148 Another potential new biomarker is the mitochondrial protein, 149 carbomoyl phosphate synthetase 1 (CPS1). This protein level 150 increases faster than aspartate transaminanse (AST) and ALT 151 within the first 3 h after APAP ingestion[18,19]. CYPS1 levels were elevated after APAP treatment in mouse and human blood, as well 153 as in hepatocytes culture medium.…”

Baicalein and its underlying mechanism as a protector against liver injury induced by cisplatin in mice

“…The present results demonstrated that baicalein prevented liver injury induced by cisplatin. Oxidative stress causes oxidative damage and has been involved in the pathogenesis of many hepatotoxininduced liver injuries [21][22][23]. Under normal conditions, the body maintains a dynamic equilibrium between the production and detoxification of free radicals via the antioxidant defence system in the body.…”