Reproducible effects of the mitochondria-targeted plastoquinone derivative SkQ1 on Drosophila melanogaster lifespan under different experimental scenarios.

Previously, extremely low, nanomolar concentrations of the mitochondria-targeted plastoquinone derivative SkQ1 (10-(6'-plastoquinonyl) decyltriphenylphosphonium) were shown to prolong the lifespan of male and female Drosophila melanogaster by about 10 % (Anisimov et al., Biochemistry (Moscow) 73:1329-1342, 2008). Using long-term monitoring of SkQ1 effects on the Drosophila lifespan, we analyzed different integral parameters of Drosophila survival and mortality under SkQ1 treatment. Meta-analysis was used to evaluate the average SkQ1 effect measured in terms of standard deviation. The effect appeared to be 0.25 for females and 0.18 for males, which corresponds to a low effect by Cohen's "Rules-of-Thumb". The SkQ1 effects on the Drosophila lifespan were reproducible over six years and showed no relationship to fluctuations in the mean lifespan of the w(1118) line used in the experiments, methods of preparation and administration of the drug, seasons, or calendar years. Adding SkQ1 to fly food was associated with a reduction in early mortality and a decrease in random variation in lifespan. All survival curves were fitted by Gompertz function. Analysis of the Gompertz function parametric plane demonstrated significant differences between points corresponding to experimental and control cohorts. The Strehler-Mildvan correlations for 11 experiments with females and for 7 experiments with males were calculated. The significant increase in the slope of the regression lines indicated that feeding flies SkQ1 reduced the rate of fall of fly vitality and, consequently, slowed aging. These findings indicated that the SkQ1 effect on lifespan was associated with both elevation of life quality and slowing of aging.

Mitochondria-targeted plastoquinone derivative SkQ1 increases early reproduction of Drosophila melanogaster at the cost of early survival.

It was previously found that 20 pM SkQ1 (10-(6'-plastoquinonyl) decyltriphenylphosphonium) solution increased lifespan of virgin females and males of the fruit fly Drosophila melanogaster with maximal and highly reproducible effect on early survival of females. In this paper we demonstrate that SkQ1 solution of the same concentration does not increase lifespan of mated females and males, early effect on female survival being absent, whereas early fertility and the total number of progeny are elevated in treated flies. Increase in fertility observed in young mated females instead of increase of survival typical for young virgin females might illustrate the trade-off between the fly's lifespan and reproduction.

[Regularory elements of the copia retrotransposon determine different levels of expression in different organs of males and females of Drosophila melanogaster].

Using a model system in which the expression of the reporter gene lacZ is under the control of five deleted variants of the copia retrotransposon regulatory region, which includes the 5'-long terminal repeat (LTR) and the 5'-untranslated region (5'-UTR), their contribution to the control of retrotransposon activity in different organs of males and females of Drosophila melanogaster was analyzed. The whole regulatory region provides expression of the reporter gene at the embryonic stage, and in larvae and adult flies only in generative organs. The 5'-end of LTR harbors a positive regulator that determines expression of the retrotransposon in organs of all types. The 3'-end of LTR harbors a negative regulator, which is sex- and time-specific: it represses copia expression in generative organs of males at all stages of development, and only at the imaginal stage in somatic tissues, without any effect on the expression of the retrotransposon in females. 5'-UTR contains a negative regulator of copia expression: it decreases the expression in embryos and generative organs and blocks it in somatic tissues. It may be suggested that a complex set of regulatory elements was formed in the course of the evolution of the retrotransposon, which made it possible to maintain a certain level of its expression in different types of cells and tissues and at different stages of development and, thus, to limit the harm caused to the host and provide the possibility for the retrotransposon to exist in the host genome over many generations.

Mitochondria-targeted plastoquinone derivatives as tools to interrupt execution of the aging program. 5. SkQ1 prolongs lifespan and prevents development of traits of senescence.

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.

[Age dependence of the level of copia retrotransposon expression in the testes of Drosophila melanogaster]. / Vozrastnaia zavisimost' ékspressii retrotranspozona copia v semennikakh Drosophila melanogaster.

Expression of the lacZ reporter gene controlled by various deletion derivatives of the regulatory region of the copia retrotransposon was studied in the testes of adult transgenic males of the Drosophila melanogaster y1W67c23(2) strain at the age of 3, 6-9, 12-15, 18-21, and 24-27 days. When the construct contained the full-length regulatory region, which included the 5'-long terminal repeat (LTR) and the 5'-untranslated region (UTR), expression was the lowest in males aged 12-15 days and the highest in males aged 3 or 24-27 days. A similar V-shaped age dependence was previously observed for the copia transposition rate and RNA content in a strain with a high rate of copia transposition. Thus, the V-shaped age dependence of expression, which is unusual for Drosophila, proved to be characteristic of copia regardless of its transposition rate. Deletion of the 5' or 3' end of the LTR, but not of the UTR, changed the age dependence of the level of reporter gene expression. In this case, expression was the highest in 3-day-old males and gradually decreased with age, as typical for many Drosophila genes. It was assumed that the 5'- and 3'-terminal regions of the copia LTR contain regulatory elements responsible for the V-shaped age dependence of expression, while the expression level depends to a greater extent on the regulatory elements of UTR.

[Regulatory elements of copia retrotransposons, controlling the level of its expression in Drosophila melanogaster testes]. / Reguliatornye élementy retrotranspozona copia, kontroliruiushchie uroven' ego ékspressii v semennikakh Drosophila melanogaster.

Expression of the lacZ reporter gene under the control of five deletion derivatives of the copia regulatory region including the 5' long terminal repeat (LTR) and the 5' untranslated region (UTR) was assayed in the testes of transgenic Drosophila melanogaster males (larvae and imago). The full-length copia regulatory region (LTR + UTR) ensured expression of the reporter gene in testes of both larvae and adult males. Deletion of UTR or 3' end of LTR increased lacZ expression in the testes, whereas deletion of the 5' end of LTR increased it. This indicated that a positive regulator of copia expression is at the 5' end of LTR and that negative regulators are at the 3' end of LTR and in UTR. The effects of the fragments of the copia regulatory region on reporter gene expression in the testes in vivo did not completely coincide with the effects observed earlier in cultured cells. We suggest that this difference is due to different regulation of expression of the fusion constructs integrated into chromatin as compared to their transient expression.