Interaction of Agaric Acid with the Adenine Nucleotide Translocase Induces Mitochondrial Oxidative Stress

Abstract

Mitochondrial permeability transition is characterized by the opening of a transmembranal pore that switches membrane permeability from specific to nonspecific. This structure allows the free traffic of ions, metabolites, and water across the mitochondrial inner membrane. The opening of the permeability transition pore is triggered by oxidative stress along with calcium overload. In this work, we explored if oxidative stress is a consequence, rather than an effector of the pore opening, by evaluating the interaction of agaric acid with the adenine nucleotide translocase, a structural component of the permeability transition pore. We found that agaric acid induces transition pore opening, increases the generation of oxygen-derived reactive species, augments the oxidation of unsaturated fatty acids in the membrane, and promotes the detachment of cytochrome c from the inner membrane. The effect of agaric acid was inhibited by the antioxidant tamoxifen in association with decreased binding of the thiol reagent eosin-3 maleimide to the adenine nucleotide translocase. We conclude that agaric acid promotes the opening of the pore, increasing ROS production that exerts oxidative modification of critical thiols in the adenine nucleotide translocase.

Adenine nucleotide translocase: Current knowledge in post‐translational modifications, regulations and pathological implications for human diseases

“…Binds exclusively on the matrix side of ANT, locks ANTs in an m-state, inhibiting ADP/ATP transportation [10] Cardiolipin Binds to ANT to stabilize an active dimeric structure of ANTs [46][47][48] Free long-chain fatty acids Activate uncoupling mediated by mitochondrial ANTs; promote the exchange of ATP and ADP (18-carbon unsaturated fatty acid); facilitate mPTP opening by stabilizing ANTs in c-conformation [49][50][51] Agaric acid Negatively charged agaric acid interacts with cationic groups in ANTs, attenuating exchange of ADP/ATP and promoting mPTP opening, and augmenting ROS generation [52,53] Long chain acylcoenzyme A esters Inhibits ADP/ATP transport from both the cytosolic and matrix sides of ANTs [54,55] Others Eosin maleimide Attacks thiol group of Cys159, stimulating mPTP opening [55,56] requires high calcium that is proposed to bind to cardiolipin molecules, which are tightly associated with the ANT. 43 4.1.2 | Carbon monoxide CO originates from heme degradation in cells, and is described as an anti-apoptotic factor at low concentration.…”

“…Through interacting with ANT, agaric acid attenuates the exchange of ADP/ATP, promotes the mPTP opening, augments ROS generation, increases a progressive efflux of accumulated calcium, and induces collapse of transmembrane potential and mitochondrial swelling. 53,57 Agaric acid possesses three carboxylic acids which can be dissociated to carry negative charges, which may interact with cationic groups formed by Lys145, Arg151, Lys162, Lys165, and Arg170 in the nucleotide-binding site of ANT. Such an interaction, combining with a hydrophobic force between the alkyl chain of agaric acid and insoluble environment of ANT in the mitochondrial membrane, fixes ANT on the cytosol side.…”

“…After that, accumulated evidences illustrate that agaric acid acts on ANT to exert an extensive effect on cell fates. Through interacting with ANT, agaric acid attenuates the exchange of ADP/ATP, promotes the mPTP opening, augments ROS generation, increases a progressive efflux of accumulated calcium, and induces collapse of transmembrane potential and mitochondrial swelling 53,57 . Agaric acid possesses three carboxylic acids which can be dissociated to carry negative charges, which may interact with cationic groups formed by Lys145, Arg151, Lys162, Lys165, and Arg170 in the nucleotide‐binding site of ANT.…”

Direct and indirect targets of carboxyatractyloside, including overlooked toxicity toward nucleoside diphosphate kinase (NDPK) and mitochondrial H + leak

“…However, the antioxidant action of tamoxifen, which is also capable of preventing the binding of some undesirable ligands to AAC, such as agaric acid, might be beneficial for mammals exposed to different toxicants (Chávez et al. 2020 ).…”

The Joint Influence of Tl+ and Thiol-Modifying Agents on Rat Liver Mitochondrial Parameters In Vitro

“…It is necessary to take into account the interaction of some MPTP inducers with the IMM lipid component (acridines and oleate) [ 17 , 18 ]. MPTP opening has been found in calcium-loaded rat kidney mitochondria (RKM) in the presence of agaric acid, acridine orange and 10-N-nonyl acridine orange (probes for cardiolipin), and oleate (interacting with the inner membrane lipid component), as well as ethidium bromide (cationic probe) [ 17 , 18 , 19 , 20 , 21 ]. We showed previously that these phenomena resulted in Tl + -induced MPTP opening, which occurred in experiments in vitro with calcium-loaded mitochondria [ 22 ].…”