Effect of Simvastatin , Coenzyme Q 10 , Resveratrol , Acetylcysteine and Acetylcarnitine on Mitochondrial Respiration ( mitochondria / simvastatin / coenzyme Q 10 / resveratrol / acetylcysteine / acetylcarnitine )

Some therapeutic and/or adverse effects of drugs may be related to their effects on mitochondrial function. The effects of simvastatin, resveratrol, coenzyme Q10, acetylcysteine, and acetylcarnitine on Complex I-, Complex II-, or Complex IV-linked respiratory rate were determined in isolated brain mitochondria. The protective effects of these biologically active compounds on the calcium-induced de crease of the respiratory rate were also studied. We observed a significant inhibitory effect of simvastatin on mitochondrial respiration (IC50 = 24.0 μM for Complex I-linked respiration, IC50 = 31.3 μM for Complex II-linked respiration, and IC50 = 42.9 μM Received August 27, 2015. Accepted December 16, 2015. The work was supported by project PRVOUK-P26/LF1/4 award­ ed by Charles University in Prague and grant AZV 15-28967A from the Ministry of Health, Czech Republic. Corresponding author: Zdeněk Fišar, Department of Psychiatry, First Faculty of Medicine, Charles University in Prague, Ke Karlo­ vu 11, 120 00 Prague 2, Czech Republic, Phone: (+420) 224 965 313; e-mail: zfisar@lf1.cuni. cz Abbreviations: ADP ‒ adenosine diphosphate, AMP – adenosine monophosphate, AMPK – AMP-activated kinase, ANTI ‒ anti­ mycin A, ATP ‒ adenosine triphosphate, CMF ‒ crude mitochon­ drial fraction, CoQ10 ‒ coenzyme Q10, DIG ‒ digitonin, DMSO ‒ dimethyl sulphoxide, Epac1 – exchange protein activated by cAMP, ETS ‒ electron transfer system, HMG-CoA – 3-hydroxy3-methylglutaryl-coenzyme A, IC50 ‒ half maximal inhibitory concentration, M ‒ malate, MiR05 ‒ mitochondrial respiration medium, MPT – mitochondral permeability transition, MPTP – MTP pore, mtDNA – mitochondral DNA, NADH ‒ nicotinamide adenine dinucleotide, OXPHOS ‒ oxidative phosphorylation, P ‒ pyruvate, Pi ‒ inorganic phosphate, PGC-1α – peroxisome prolif­ erator-activated receptor γ coactivator α, PMP ‒ mitochondria purified in Percoll gradient, PMS ‒ mitochondria purified in su­ crose gradient, ROS ‒ reactive oxygen species, ROT ‒ rotenone, ROX ‒ residual oxygen consumption, S ‒ succinate, SD – standard deviation, SE – standard error, SIRT1 – sirtuin 1, TMPD ‒ N,N,N′,N′­tetramethyl­p­phenyl enedia mine. for Complex IV-linked respiration); the inhibitory effect of resveratrol was found at very high concentrations (IC50 = 162 μM for Complex I-linked respiration, IC50 = 564 μM for Complex II-linked respiration, and IC50 = 1454 μM for Complex IV-linked respiration). Concentrations required for effective simvastatinor resveratrol-induced inhibition of mitochondrial respiration were found much higher than concentrations achieved under standard dosing of these drugs. Acetylcysteine and acetylcarnitine did not affect the oxygen consumption rate of mitochondria. Coenzyme Q10 induced an increase of Complex I-linked respiration. The increase of free calcium ions induced partial inhibition of the Complex I+II-linked mitochondrial respiration, and all tested drugs counteracted this inhibition. None of the tested drugs showed mitochondrial toxicity (characterized by respiratory rate inhibition) at drug concentrations achieved at therapeutic drug intake. Resveratrol, simvastatin, and acetylcarnitine had the greatest neuroprotective potential (characterized by protective effects against calcium-induced reduction of the respiratory rate).