Synergistic effect of Ca2+ and peroxidized cardiolipin in the induction of permeability transition and cytochrome c release in rat heart mitochondria.
ABSTRACT The effect of peroxidized cardiolipin on the mitochondrial pore transition (MPT) induction and cytochrome c release in rat heart mitochondria was studied. Treatment of mitochondria with cardiolipin hydroperoxide (CLOOH) promoted matrix swelling and release of cytochrome c. Both these processes were inhibited by cyclosporine A and bongkrekic acid, indicating that peroxidized cardiolipin behaves as an inducer of MPT. Ca2+ accumulation was required for this effect. ANT (ADP/ATP carrier) is involved in the CLOOH-dependent MPT induction as suggested by the modulation by ligands and inhibitors of ANT. These results indicate that CLOOH lowers the threshold of Ca2+ for MPT induction. This synergistic effect of Ca2+ and CLOOH on MPT induction and cytochrome c release in mitochondria might have important implications in the apoptotic process as well as in several pathophysiological situations.
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ABSTRACT: Mitochondrial medicine is an evolving discipline whose importance derives from the central function of mitochondria in adenosine triphosphate (ATP) production, generation of reactive oxygen species, and cell death by necrosis or apoptosis. Consequently, mitochondrial dysfunction plays an important role in the progression of aging and the pathophysiology of many common diseases and off-target drug effects. This provides an impetus for the development of mitochondrial pharmacology, and some promising therapeutic targets for mitochondrial protective therapy have been identified.Clinical pharmacology and therapeutics. 12/2014; 96(6):629-33.
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ABSTRACT: A decline in energy is common in aging, and the restoration of mitochondrial bioenergetics may offer a common approach for the treatment of numerous age-associated diseases. Cardiolipin is a unique phospholipid that is exclusively expressed on the inner mitochondrial membrane where it plays an important structural role in cristae formation and the organization of the respiratory complexes into supercomplexes for optimal oxidative phosphorylation. The interaction between cardiolipin and cytochrome c determines whether cytochrome c acts as an electron carrier or peroxidase. Cardiolipin peroxidation and depletion have been reported in a variety of pathological conditions associated with energy deficiency, and cardiolipin has been identified as a target for drug development. This review focuses on the discovery and development of the first cardiolipin-protective compound as a therapeutic agent. SS-31 is a member of the Szeto-Schiller (SS) peptides known to selectively target the inner mitochondrial membrane. SS-31 binds selectively to cardiolipin via electrostatic and hydrophobic interactions. By interacting with cardiolipin, SS-31 prevents cardiolipin from converting cytochrome c into a peroxidase while protecting its electron carrying function. As a result, SS-31 protects the structure of mitochondrial cristae and promotes oxidative phosphorylation. SS-31 represents a new class of compounds that can recharge the cellular powerhouse and restore bioenergetics. Extensive animal studies have shown that targeting such a fundamental mechanism can benefit highly complex diseases that share a common pathogenesis of bioenergetics failure. This review summarizes the mechanisms of action and therapeutic potential of SS-31 and provides an update of its clinical development programme.Linked ArticlesThis article is part of a themed issue on Mitochondrial Pharmacology: Energy, Injury & Beyond. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2014.171.issue-8British Journal of Pharmacology 04/2014; 171(8). · 5.07 Impact Factor
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ABSTRACT: Diets replete with n-3 PUFAs (polyunsaturated fatty acids) are known to have therapeutic potential for the heart, although a specifically defined duration of the n-3 PUFA diet required to achieve these effects remains unknown, as does their mechanism of action. The present study was undertaken to establish whether adaptations in mitochondrial function and stress tolerance in the heart is evident following short- (3 weeks) and long- (14 weeks) term dietary intervention of n-3 PUFAs, and to identify novel mechanisms by which these adaptations occur. Mitochondrial respiration [mO2 (mitochondrial O2)], H2O2 emission [mH2O2 (mitochondrial H2O2)] and Ca2+-retention capacity [mCa2+ (mitochondrial Ca2+)] were assessed in mouse hearts following dietary intervention. Mice fed n-3 PUFAs for 14 weeks showed significantly lower mH2O2 and greater mCa2+ compared with all other groups. However, no significant differences were observed after 3 weeks of the n-3 PUFA diet, or in mice fed on an HFC (high-fat control) diet enriched with vegetable shortening, containing almost no n-3 PUFAs, for 14 weeks. Interestingly, expression and activity of key enzymes involved in antioxidant and phase II detoxification pathways, all mediated by Nrf2 (nuclear factor E2-related factor 2), were elevated in hearts from mice fed the n-3 PUFA diet, but not hearts from mice fed the HFC diet, even at 3 weeks. This increase in antioxidant systems in hearts from mice fed the n-3 PUFA diet was paralleled by increased levels of 4-hydroxyhexenal protein adducts, an aldehyde formed from peroxidation of n-3 PUFAs. The findings of the present study demonstrate distinct time-dependent effects of n-3 PUFAs on mitochondrial function and antioxidant response systems in the heart. In addition, they are the first to provide direct evidence that non-enzymatic oxidation products of n-3 PUFAs may be driving mitochondrial and redox-mediated adaptations, thereby revealing a novel mechanism for n-3 PUFA action in the heart.Biochemical Journal 08/2011; 441(1):359-66. · 4.65 Impact Factor