Chronobiotics KL001 and KS15 Extend Lifespan and Modify Circadian Rhythms of Drosophila melanogaster

Abstract

Chronobiotics are a group of drugs, which are utilized to modify circadian rhythms targeting clock-associated molecular mechanisms. The circadian clock is known as a controller of numerous processes in connection with aging. Hypothesis: KL001 and KS15 targeting CRY, affect lifespan, locomotor activity and circadian rhythm of Drosophila melanogaster. We observed a slight (2%, p < 0.001) geroprotective effect on median lifespan (5 µM solution of KL001 in 0.1% DMSO) and a 14% increase in maximum lifespan in the same group. KS15 10 µM solution extended males' median lifespan by 8% (p < 0.05). The statistically significant positive effects of KL001 and KS15 on lifespan were not observed in female flies. KL001 5 µM solution improved locomotor activity in young male imagoes (p < 0.05), elevated morning activity peak in aged imagoes and modified robustness of their circadian rhythms, leaving the period intact. KS15 10 µM solution decreased the locomotor activity in constant darkness and minimized the number of rhythmic flies. KL001 5 µM solution improved by 9% the mean starvation resistance in male flies (p < 0.01), while median resistance was elevated by 50% (p < 0.0001). This phenomenon may suggest the presence of the mechanism associated with improvement of fat body glucose depos' utilization in starvation conditions which is activated by dCRY binding KL001.

Keywords: Drosophila melanogaster; KL001; KS15; chronobiotics; cryptochrome; geroprotectors.

Figure 1

The locomotor activity profiles measured for CS males treated with lifespan modifying doses of KL001 и KS15 until the age of 5–12 days: (a,d)—activity per day in LD and DD; (b,e)—activity distributions in LD and DD; (c,f)—mean activities in LD and DD; (g)—profile of locomotor activity in LD, measured as an average per minute; (h)—actograms, presenting and comparing all the profile during six days of test, first to lines are LD, last four—DD in all three blocks; *—p < 0.0001 significant results, according to ANOVA with Tukey/Kramer procedure, p < 0.01 with Scheffe’s procedure for KS15 (c,f); *—p < 0.05, Mann-Whitney test for control vs. KL001 comparison. The effect on locomotor activity was observed both in LD and DD for KL001 cohort and for KS15 in DD, the daily activity profile in LD was elevated by KL001 5 µM solution in young age.

Figure 2

The locomotor activity profiles measured for CS males treated with lifespan modifying doses of KL001 и KS15 until the age of 34–41 days: (a,d)—activity per day in LD and DD; (b,e)—activity distributions in LD and DD; (c,f)—mean activities in LD and DD; (g)—profile of locomotor activity in LD, measured as an average per minute; (h)—actogramms, presenting and comparing all the profile during six days of test, first to lines are LD, last four—DD in all three blocks; *—p < 0.0001 significant results, according to ANOVA with Tukey/Kramer procedure, p < 0.001 with Scheffe’s procedure (c,f); *—p < 0.05, Mann-Whitney test for control vs. KL001 comparison (g). In older age we observed only the effect on locomotor activity in a group which received 10 µM solution of KS15.

Figure 3

The parameters of male flies’ circadian rhythms, sleep/activity profile until the age of 5–12 days: (a)—circadian period robustness; (b)—circadian period peaks’ quantitative representation; (c)—mean periodogram, (d)—individual periodograms, (e)—total sleep in LD, (f)—sleep bout number in LD, *—p < 0.05, Mann-Whitney test; (g)—comparative diagram daytime vs. night-time activity in LD, *—0.001 ANOVA with Tukey/Kramer procedure, also p < 0.01 with Scheffe’s procedure, for light and dark periods of the day, +—p < 0.001—for light and light in different cohorts by treatment, (h)—sleep profile the differences in local distributions were measured with ANOVA for the control and KL001 groups. The chronobiotics did not significantly alter the period of the circadian rhythms in male flies of young age, but seriously affected the sleep profile in KL001-treated cohort; the sleep bout number decreased by 20% (p < 0.05). The total activity was higher in daytime in the KL001 cohort as well as in night-time. Night-time activity was higher in all cohorts relative to daytime but not in the control group.

Figure 4

The parameters of male flies’ circadian rhythms, sleep/activity profile until the age of 34–41 days: (a)—circadian period robustness; (b)—circadian period peaks’ quantitative representation; (c)—mean periodogram, (d)—individual periodograms, (e)—total sleep in LD, (f)—sleep bout number in LD, *—p < 0.05, Mann-Whitney test; (g)—comparative diagram daytime vs. nighttime activity in LD, *—p < 0.001 ANOVA with Tukey/Kramer procedure, also p < 0.01 with Scheffe’s procedure, for light and dark periods of the day, +—for light and light in different cohorts by treatment, (h)—sleep profile for the differences in local distributions were measured with ANOVA for the control and KL001 groups. We observed only a total daytime activity elevation in the KL001 cohort of old age (p < 0.01).