Cations SkQ1 and MitoQ Accumulated in Mitochondria Delay Opening of Ascorbate/FeSO₄-Induced Nonspecific Pore in the Inner Mitochondrial Membrane

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L. S. Khailova, V. I. Dedukhova, and E. N. Mokhova^*

Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia; fax: (495) 939-5530; E-mail: mokhova@genebee.msu.su

^* To whom correspondence should be addressed.

Received March 18, 2008

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It is known that an addition of FeSO₄ in the presence of ascorbic acid to cells or mitochondria can injure energy coupling and some other functions in mitochondria. The present study demonstrates that decrease in ascorbate concentration from 4 to 0.2 mM in the presence of the same low concentrations of FeSO₄ accelerates the nonspecific pore opening, while cyclosporin A prevents and under some conditions reverses the pore opening. Hydrophobic cations SkQ1 and MitoQ (structural analogs of plastoquinone and coenzyme Q₁₀, respectively) delay pore opening, SkQ1 being more efficient. It is known that an increase in matrix ADP concentration delays pore opening, while an addition of carboxyatractylate to mitochondria accelerates the beginning of pore opening. Preliminary addition of SkQ1 into a mitochondrial suspension increased the effect of ADP and decreased the effect of carboxyatractylate. These results suggest that under the conditions used SkQ1 protects mitochondria from oxidative damage as an antioxidant when added at extremely low concentrations.

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KEY WORDS: mitochondria, nonspecific Ca²⁺-dependent cyclosporin A-sensitive pore, oxidative stress, SkQ1, MitoQ, antioxidants

DOI: 10.1134/S0006297908100088

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