Acetaminophen inhibits cytochrome c redox cycling induced lipid peroxidation

Abstract

Cytochrome (cyt) c can uncouple from the respiratory chain following mitochondrial stress and catalyze lipid peroxidation. Accumulating evidence shows that this phenomenon impairs mitochondrial respiratory function and also initiates the apoptotic cascade. Therefore, under certain conditions a pharmacological approach that can inhibit cyt c catalyzed lipid peroxidation may be beneficial. We recently showed that acetaminophen (ApAP) at normal pharmacologic concentrations can prevent hemoprotein-catalyzed lipid peroxidation in vitro and in vivo by reducing ferryl heme to its ferric state. We report here, for the first time, that ApAP inhibits cytochrome c-catalyzed oxidation of unsaturated free fatty acids and also the mitochondrial phospholipid, cardiolipin. Using isolated mitochondria, we also showed that ApAP inhibits cardiolipin oxidation induced by the pro-apoptotic protein, tBid. We found that the IC50 of the inhibition of cardiolipin oxidation by ApAP is similar in both intact isolated mitochondria and cardiolipin liposomes, suggesting that ApAP penetrates well into the mitochondria. Together with our previous results, the findings presented herein suggest that ApAP is a pleiotropic inhibitor of peroxidase catalyzed lipid peroxidation. Our study also provides a potentially novel pharmacological approach for inhibiting the cascade of events that can result from redox cycling of cyt c.

Cardiolipin fatty acid remodeling regulates mitochondrial function by modifying the electron entry point in the respiratory chain

“…Increased proton leaks lead to enhanced state 4 oxygen consumption, indicating a compensatory increase in electron transfer which is however associated with the increased “electron leakage” from the electron transport chain to oxygen producing superoxide (Dikalova et al , 2010). ApAP improves cardiolipin composition and reduces cardiolipin oxidation (Yin et al, 2012), which reduces proton leaks and results in improved respiratory control ratio and diminished electron leakage to superoxide formation (Dikalova et al , 2015). …”

“…Analysis of cardiolipin content was performed as previously described (Yin et al , 2012). Briefly, lipids were extracted from 6 × 10 6 cells by addition of 0.75% NaCl and chloroform:methanol (2:1, v:v) containing 0.1 mM butyrated hydroxytoluene, 0.1 mM triphenylphosphine, and 2.5 μg tetramyristeoyl-cardiolipin (M 4 CL) as an internal standard.…”

“…In a previous study, we showed that acetaminophen (ApAP), the most widely used pain relieving and fever reducing drug in the world, potently prevents cardiolipin oxidation induced by both cytochrome c/hydrogen peroxide in liposomes and tBid in mitochondria isolated from mouse liver (Yin et al , 2012). The most abundant cardiolipin species in liver and in other organs with high metabolic rate is tetralinoleoyl-cardiolipin (L 4 CL) (Han et al , 2006).…”

Correlation between the potency of flavonoids for cytochrome c reduction and inhibition of cardiolipin‐induced peroxidase activity

“…Although there is debate on the mechanism(s) of Cyt c release by mitochondria, it is well accepted that CL plays an important role in this process , and recent works showed that Cyt c can open nanoscale pores and cross through CL‐containing membranes . On these grounds, the modulation of Cyt c interaction with CL and identification of potential inhibitors of CL‐induced peroxidase activity have a priori a high relevance . Indeed, some of these inhibitors have shown anti‐apoptotic and neuroprotective actions in cellular and animal models of acute injury .…”

Formation of electrophilic oxidation products from mitochondrial cardiolipin in vitro and in vivo in the context of apoptosis and atherosclerosis

“…Interestingly, we observed dose-dependent inhibition of CL oxidation and formation of EAA-CL by a widely used analgesic drug acetaminophen (ApAP) that also served as a peroxidase inhibitor [15]. Furthermore, the very mechanism appeared to operate in vivo in the settings of atherosclerosis in a mice model of Western diet-induced atherosclerosis using low density lipoprotein receptor knockout (LDLR −/−) mice.…”