Biochemistry (Moscow) (v.73, #12)

Mitochondria-targeted plastoquinone derivatives as tools to interrupt execution of the aging program. 1. Cationic plastoquinone derivatives: Synthesis and in vitro studies by Y. N. Antonenko; A. V. Avetisyan; L. E. Bakeeva; B. V. Chernyak; V. A. Chertkov; L. V. Domnina; O. Yu. Ivanova; D. S. Izyumov; L. S. Khailova; S. S. Klishin; G. A. Korshunova; K. G. Lyamzaev; M. S. Muntyan; O. K. Nepryakhina; A. A. Pashkovskaya; O. Yu. Pletjushkina; A. V. Pustovidko; V. A. Roginsky; T. I. Rokitskaya; E. K. Ruuge; V. B. Saprunova; I. I. Severina; R. A. Simonyan; I. V. Skulachev; M. V. Skulachev; N. V. Sumbatyan; I. V. Sviryaeva; V. N. Tashlitsky; J. M. Vassiliev; M. Yu. Vyssokikh; L. S. Yaguzhinsky; A. A. Zamyatnin Jr.; V. P. Skulachev (1273-1287).
Synthesis of cationic plastoquinone derivatives (SkQs) containing positively charged phosphonium or rhodamine moieties connected to plastoquinone by decane or pentane linkers is described. It is shown that SkQs (i) easily penetrate through planar, mitochondrial, and outer cell membranes, (ii) at low (nanomolar) concentrations, posses strong antioxidant activity in aqueous solution, BLM, lipid micelles, liposomes, isolated mitochondria, and cells, (iii) at higher (micromolar) concentrations, show pronounced prooxidant activity, the “window” between anti- and prooxidant concentrations being very much larger than for MitoQ, a cationic ubiquinone derivative showing very much lower antioxidant activity and higher prooxidant activity, (iv) are reduced by the respiratory chain to SkQH2, the rate of oxidation of SkQH2 being lower than the rate of SkQ reduction, and (v) prevent oxidation of mitochondrial cardiolipin by OH·. In HeLa cells and human fibroblasts, SkQs operate as powerful inhibitors of the ROS-induced apoptosis and necrosis. For the two most active SkQs, namely SkQ1 and SkQR1, C 1/2 values for inhibition of the H2O2-induced apoptosis in fibroblasts appear to be as low as 1·10−11 and 8·10−13 M, respectively. SkQR1, a fluorescent representative of the SkQ family, specifically stains a single type of organelles in the living cell, i.e. energized mitochondria. Such specificity is explained by the fact that it is the mitochondrial matrix that is the only negatively-charged compartment inside the cell. Assuming that the Δψ values on the outer cell and inner mitochondrial membranes are about 60 and 180 mV, respectively, and taking into account distribution coefficient of SkQ1 between lipid and water (about 13,000: 1), the SkQ1 concentration in the inner leaflet of the inner mitochondrial membrane should be 1.3·108 times higher than in the extracellular space. This explains the very high efficiency of such compounds in experiments on cell cultures. It is concluded that SkQs are rechargeable, mitochondria-targeted antioxidants of very high efficiency and specificity. Therefore, they might be used to effectively prevent ROS-induced oxidation of lipids and proteins in the inner mitochondrial membrane in vivo.
Keywords: SkQ1; penetrating cations; plastoquinone; antioxidants; mitochondria; apoptosis

Mitochondria-targeted plastoquinone derivatives as tools to interrupt execution of the aging program. 2. Treatment of some ROS- and Age-related diseases (heart arrhythmia, heart infarctions, kidney ischemia, and stroke) by L. E. Bakeeva; I. V. Barskov; M. V. Egorov; N. K. Isaev; V. I. Kapelko; A. V. Kazachenko; V. I. Kirpatovsky; S. V. Kozlovsky; V. L. Lakomkin; S. B. Levina; O. I. Pisarenko; E. Y. Plotnikov; V. B. Saprunova; L. I. Serebryakova; M. V. Skulachev; E. V. Stelmashook; I. M. Studneva; O. V. Tskitishvili; A. K. Vasilyeva; I. V. Victorov; D. B. Zorov; V. P. Skulachev (1288-1299).
Effects of 10-(6′-plastoquinonyl) decyltriphenylphosphonium (SkQ1) and 10-(6′-plastoquinonyl) decylrhod-amine 19 (SkQR1) on rat models of H2O2- and ischemia-induced heart arrhythmia, heart infarction, kidney ischemia, and stroke have been studied ex vivo and in vivo. In all the models listed, SkQ1 and/or SkQR1 showed pronounced protective effect. Supplementation of food with extremely low SkQ1 amount (down to 0.02 nmol SkQ1/kg per day for 3 weeks) was found to abolish the steady heart arrhythmia caused by perfusion of isolated rat heart with H2O2 or by ischemia/reperfusion. Higher SkQ1 (125–250 nmol/kg per day for 2–3 weeks) was found to decrease the heart infarction region induced by an in vivo ischemia/reperfusion and lowered the blood levels of lactate dehydrogenase and creatine kinase increasing as a result of ischemia/reperfusion. In single-kidney rats, ischemia/reperfusion of the kidney was shown to kill the majority of the animals in 2–4 days, whereas one injection of SkQ1 or SkQR1 (1 μmol/kg a day before ischemia) saved lives of almost all treated rats. Effect of SkQR1 was accompanied by decrease in ROS (reactive oxygen species) level in kidney cells as well as by partial or complete normalization of blood creatinine and of some other kidney-controlled parameters. On the other hand, this amount of SkQ1 (a SkQ derivative of lower membrane-penetrating ability than SkQR1) saved the life but failed to normalize ROS and creatinine levels. Such an effect indicates that death under conditions of partial kidney dysfunction is mediated by an organ of vital importance other than kidney, the organ in question being an SkQ1 target. In a model of compression brain ischemia/reperfusion, a single intraperitoneal injection of SkQR1 to a rat (1 μmol/kg a day before operation) effectively decreased the damaged brain area. SkQ1 was ineffective, most probably due to lower permeability of the blood-brain barrier to this compound.
Keywords: mitochondria-targeted antioxidant; plastoquinone; arrhythmia; heart; kidney; infarction; stroke

Mitochondria-targeted plastoquinone derivatives as tools to interrupt execution of the aging program. 3. Inhibitory effect of SkQ1 on tumor development from p53-deficient cells by L. S. Agapova; B. V. Chernyak; L. V. Domnina; V. B. Dugina; A. Yu. Efimenko; E. K. Fetisova; O. Yu. Ivanova; N. I. Kalinina; N. V. Khromova; B. P. Kopnin; P. B. Kopnin; M. V. Korotetskaya; M. R. Lichinitser; A. L. Lukashev; O. Yu. Pletjushkina; E. N. Popova; M. V. Skulachev; G. S. Shagieva; E. V. Stepanova; E. V. Titova; V. A. Tkachuk; J. M. Vasiliev; V. P. Skulachev (1300-1316).
It was proposed that increased level of mitochondrial reactive oxygen species (ROS), mediating execution of the aging program of an organism, could also be critical for neoplastic transformation and tumorigenesis. This proposal was addressed using new mitochondria-targeted antioxidant SkQ1 (10-(6′-plastoquinonyl) decyltriphenylphosphonium) that scavenges ROS in mitochondria at nanomolar concentrations. We found that diet supplementation with SkQ1 (5 nmol/kg per day) suppressed spontaneous development of tumors (predominantly lymphomas) in p53-/- mice. The same dose of SkQ1 inhibited the growth of human colon carcinoma HCT116/p53-/- xenografts in athymic mice. Growth of tumor xenografts of human HPV-16-associated cervical carcinoma SiHa was affected by SkQ1 only slightly, but survival of tumor-bearing animals was increased. It was also shown that SkQ1 inhibited the tumor cell proliferation, which was demonstrated for HCT116 p53-/- and SiHa cells in culture. Moreover, SkQ1 induced differentiation of various tumor cells in vitro. Coordinated SkQ1-initiated changes in cell shape, cytoskeleton organization, and E-cadherin-positive intercellular contacts were observed in epithelial tumor cells. In Ras- and SV40-transformed fibroblasts, SkQ1 was found to initiate reversal of morphological transformation of a malignant type, restoring actin stress fibers and focal adhesion contacts. SkQ1 suppressed angiogenesis in Matrigel implants, indicating that mitochondrial ROS could be important for tumor angiogenesis. This effect, however, was less pronounced in HCT116/p53-/- tumor xenografts. We have also shown that SkQ1 and related positively charged antioxidants are substrates of the P-glycoprotein multidrug resistance pump. The lower anti-tumor effect and decreased intracellular accumulation of SkQ1, found in the case of HCT116 xenografts bearing mutant forms of p53, could be related to a higher level of P-glycoprotein. The effects of traditional antioxidant N-acetyl-L-cysteine (NAC) on tumor growth and tumor cell phenotype were similar to the effects of SkQ1 but more than 1,000,000 times higher doses of NAC than those of SkQ1 were required. Extremely high efficiency of SkQ1, related to its accumulation in the mitochondrial membrane, indicates that mitochondrial ROS production is critical for tumorigenesis at least in some animal models.
Keywords: mitochondria-targeted antioxidant; tumorigenesis; tumor cells

Mitochondria-targeted plastoquinone derivatives as tools to interrupt execution of the aging program. 4. Age-related eye disease. SkQ1 returns vision to blind animals by V. V. Neroev; M. M. Archipova; L. E. Bakeeva; A. Zh. Fursova; E. N. Grigorian; A. Yu. Grishanova; E. N. Iomdina; Zh. N. Ivashchenko; L. A. Katargina; I. P. Khoroshilova-Maslova; O. V. Kilina; N. G. Kolosova; E. P. Kopenkin; S. S. Korshunov; N. A. Kovaleva; Yu. P. Novikova; P. P. Philippov; D. I. Pilipenko; O. V. Robustova; V. B. Saprunova; I. I. Senin; M. V. Skulachev; L. F. Sotnikova; N. A. Stefanova; N. K. Tikhomirova; I. V. Tsapenko; A. I. Shchipanova; R. A. Zinovkin; V. P. Skulachev (1317-1328).
Mitochondria-targeted cationic plastoquinone derivative SkQ1 (10-(6′-plastoquinonyl) decyltriphenylphosphonium) has been investigated as a potential tool for treating a number of ROS-related ocular diseases. In OXYS rats suffering from a ROS-induced progeria, very small amounts of SkQ1 (50 nmol/kg per day) added to food were found to prevent development of age_induced cataract and retinopathies of the eye, lipid peroxidation and protein carbonylation in skeletal muscles, as well as a decrease in bone mineralization. Instillation of drops of 250 nM SkQ1 reversed cataract and retinopathies in 3-12-month-old (but not in 24-month-old) OXYS rats. In rabbits, experimental uveitis and glaucoma were induced by immunization with arrestin and injections of hydroxypropyl methyl cellulose to the eye anterior sector, respectively. Uveitis was found to be prevented or reversed by instillation of 250 nM SkQ1 drops (four drops per day). Development of glaucoma was retarded by drops of 5 μM SkQ1 (one drop daily). SkQ1 was tested in veterinarian practice. A totally of 271 animals (dogs, cats, and horses) suffering from retinopathies, uveitis, conjunctivitis, and cornea diseases were treated with drops of 250 nM SkQ1. In 242 cases, positive therapeutic effect was obvious. Among animals suffering from retinopathies, 89 were blind. In 67 cases, vision returned after SkQ1 treatment. In ex vivo studies of cultivated posterior retina sector, it was found that 20 nM SkQ1 strongly decreased macrophagal transformation of the retinal pigmented epithelial cells, an effect which might explain some of the above SkQ1 activities. It is concluded that low concentrations of SkQ1 are promising in treating retinopathies, cataract, uveitis, glaucoma, and some other ocular diseases.
Keywords: mitochondria; antioxidants; retinopathies; cataract; uveitis; glaucoma

Mitochondria-targeted plastoquinone derivatives as tools to interrupt execution of the aging program. 5. SkQ1 prolongs lifespan and prevents development of traits of senescence by V. N. Anisimov; L. E. Bakeeva; P. A. Egormin; O. F. Filenko; E. F. Isakova; V. N. Manskikh; V. M. Mikhelson; A. A. Panteleeva; E. G. Pasyukova; D. I. Pilipenko; T. S. Piskunova; I. G. Popovich; N. V. Roshchina; O. Yu. Rybina; V. B. Saprunova; T. A. Samoylova; A. V. Semenchenko; M. V. Skulachev; I. M. Spivak; E. A. Tsybul’ko; M. L. Tyndyk; M. Yu. Vyssokikh; M. N. Yurova; M. A. Zabezhinsky; V. P. Skulachev (1329-1342).
Very low (nano- and subnanomolar) concentrations of 10-(6′-plastoquinonyl) decyltriphenylphosphonium (SkQ1) were found to prolong lifespan of a fungus (Podospora anserina), a crustacean (Ceriodaphnia affinis), an insect (Drosophila melanogaster), and a mammal (mouse). In the latter case, median lifespan is doubled if animals live in a non-sterile vivarium. The lifespan increase is accompanied by rectangularization of the survival curves (an increase in survival is much larger at early than at late ages) and disappearance of typical traits of senescence or retardation of their development. Data summarized here and in the preceding papers of this series suggest that mitochondria-targeted antioxidant SkQ1 is competent in slowing down execution of an aging program responsible for development of age-related senescence.
Keywords: SkQ1; antioxidants; mitochondria; aging; senescence; therapy

Notable and anniversary dates in biochemistry for 2009 by N. P. Voskresenskaya (1343-1347).

Gaucher disease by G. Ya. Wiederschain (1348-1349).

Principles and practice of bioanalysis (2nd Edn.) by G. Ya. Wiederschain (1351-1351).