Angelica keiskei Impacts the Lifespan and Healthspan of Drosophila melanogaster in a Sex and Strain-Dependent Manner.

Angelica keiskei is a perennial plant, belonging to the Apiaceae family and originating from Japan. This plant has been reported to act as a diuretic, analeptic, antidiabetic, hypertensive, tumor, galactagogue, and laxative. The mechanism of action of A. keiskei is not known, but previous studies have suggested that it may act as an antioxidant. In this work, we used Drosophila melanogaster to evaluate the impact of A. keiskei on lifespan and healthspan and its potential anti-aging mechanism by conducting multiple assays on three fly strains: w1118, chico, and JIV. We observed that the extract extended lifespan and improved healthspan in a sex- and strain-dependent manner. A. keiskei extended lifespan and improved reproductive fitness in female flies and either had no effect or decreased survival and physical performance in males. The extract protected against the superoxide generator paraquat in both sexes. These sex-specific effects suggest that A. keiskei may act through age-specific pathways such as the insulin and insulin-like growth factor signaling (IIS) pathways. Upon examination, we found that the increased survival of A. keiskei-fed females was dependent on the presence of the insulin receptor substrate chico, supporting the role of IIS in the action of A. keiskei.

The mitochondrial adenine nucleotide transporters in myogenesis.

Adenine Nucleotide Translocator isoforms (ANTs) exchange ADP/ATP across the inner mitochondrial membrane, are also voltage-activated proton channels and regulate mitophagy and apoptosis. The ANT1 isoform predominates in heart and muscle while ANT2 is systemic. Here, we report the creation of Ant mutant mouse myoblast cell lines with normal Ant1 and Ant2 genes, deficient in either Ant1 or Ant2, and deficient in both the Ant1 and Ant2 genes. These cell lines are immortal under permissive conditions (IFN-γ + serum at 32 °C) permitting expansion but return to normal myoblasts that can be differentiated into myotubes at 37 °C. With this system we were able to complement our Ant1 mutant studies by demonstrating that ANT2 is important for myoblast to myotube differentiation and myotube mitochondrial respiration. ANT2 is also important in the regulation of mitochondrial biogenesis and antioxidant defenses. ANT2 is also associated with increased oxidative stress response and modulation for Ca++ sequestration and activation of the mitochondrial permeability transition (mtPTP) pore during cell differentiation.

Protection of nuclear DNA by lifespan-extending compounds in the yeast Saccharomyces cerevisiae.

DNA damage has been hypothesized to be a driving force of the aging process. At the same time, there exists multiple compounds that can extend lifespan in model organisms, such as yeast, worms, flies, and mice. One possible mechanism of action for these compounds is a protective effect against DNA damage. We investigated whether five of these lifespan-extending compounds, dinitrophenol, metformin, rapamycin, resveratrol, and spermidine, could protect nuclear DNA in the yeast Saccharomyces cerevisiae at the same doses under which they confer lifespan extension. We found that rapamycin and spermidine were able to decrease the spontaneous mutation rate at the CAN1 locus, whereas dinitrophenol, metformin, and resveratrol were able to protect yeast against CAN1 mutations induced by ethyl methanesulfonate (EMS). We also tested whether these compounds could enhance survival against EMS, ultraviolet (UV) light, or hydrogen peroxide (H2O2) insult. All five compounds conferred a protective effect against EMS, while metformin and spermidine protected yeast against UV light. Somewhat surprisingly, none of the compounds were able to afford a significant protection against H2O2, with spermidine dramatically sensitizing cells. We also examined the ability of these compounds to increase lifespan when growth-arrested by hydroxyurea; only spermidine was found to have a positive effect. Overall, our results suggest that lifespan-extending compounds may act in part by protecting nuclear DNA.

Cinnamaldehyde Improves Lifespan and Healthspan in Drosophila melanogaster Models for Alzheimer's Disease.

Cinnamon extract has been reported to have positive effects in fruit fly and mouse models for Alzheimer's disease (AD). However, cinnamon contains numerous potential active compounds that have not been individually evaluated. The main objective of this study was to evaluate the impact of cinnamaldehyde, a known putative active compound in cinnamon, on the lifespan and healthspan of Drosophila melanogaster models for Alzheimer's disease, which overexpress Aß42 and MAPT (Tau). We found that cinnamaldehyde significantly improved the lifespan of both AD and non-AD flies. Cinnamaldehyde also improved the healthspan of AD flies overexpressing the Tau protein by improving climbing ability, evaluated by rapid iterative negative geotaxis (RING), and improving short-term memory, evaluated by a courtship conditioning assay. Cinnamaldehyde had no positive impact on the healthspan of AD flies overexpressing the Aß42 protein.

Rhodiola rosea Improves Lifespan, Locomotion, and Neurodegeneration in a Drosophila melanogaster Model of Huntington's Disease.

Huntington's disease (HD) is a dominant, late-onset disease characterized by choreiform movements, cognitive decline, and personality disturbance. It is caused by a polyglutamine repeat expansion in the Huntington's disease gene encoding for the Huntingtin protein (Htt) which functions as a scaffold for selective macroautophagy. Mutant Htt (mHtt) disrupts vesicle trafficking and prevents autophagosome fusion with lysosomes, thus deregulating autophagy in neuronal cells, leading to cell death. Autophagy has been described as a therapeutic target for HD, owing to the key role Htt plays in the cellular process. Rhodiola rosea, a plant extract used in traditional medicine in Europe and Asia, has been shown to attenuate aging in the fly and other model species. It has also been shown to inhibit the mTOR pathway and induce autophagy in bladder cancer cell lines. We hypothesized that R. rosea, by inducing autophagy, may improve the phenotype of a Huntington's disease model of the fly. Flies expressing HttQ93 which exhibit decreased lifespan, impaired locomotion, and increased neurodegeneration were supplemented with R. rosea extract, and assays testing lifespan, locomotion, and pseudopupil degeneration provided quantitative measures of improvement. Based on our observations, R. rosea may be further evaluated as a potential therapy for Huntington's disease.

The impact of Rhodiola rosea on the gut microbial community of Drosophila melanogaster.

BACKGROUND: The root extract of Rhodiola rosea has historically been used in Europe and Asia as an adaptogen, and similar to ginseng and Shisandra, shown to display numerous health benefits in humans, such as decreasing fatigue and anxiety while improving mood, memory, and stamina. A similar extract in the Rhodiola family, Rhodiola crenulata, has previously been shown to confer positive effects on the gut homeostasis of the fruit fly, Drosophila melanogaster. Although, R. rosea has been shown to extend lifespan of many organisms such as fruit flies, worms and yeast, its anti-aging mechanism remains uncertain. Using D. melanogaster as our model system, the purpose of this work was to examine whether the anti-aging properties of R. rosea are due to its impact on the microbial composition of the fly gut. RESULTS: Rhodiola rosea treatment significantly increased the abundance of Acetobacter, while subsequently decreasing the abundance of Lactobacillales of the fly gut at 10 and 40 days of age. Additionally, supplementation of the extract decreased the total culturable bacterial load of the fly gut, while increasing the overall quantifiable bacterial load. The extract did not display any antimicrobial activity when disk diffusion tests were performed on bacteria belonging to Microbacterium, Bacillus, and Lactococcus. CONCLUSIONS: Under standard and conventional rearing conditions, supplementation of R. rosea significantly alters the microbial community of the fly gut, but without any general antibacterial activity. Further studies should investigate whether R. rosea impacts the gut immunity across multiple animal models and ages.

Green tea polyphenols require the mitochondrial iron transporter, mitoferrin, for lifespan extension in Drosophila melanogaster.

Green tea has been found to increase the lifespan of various experimental animal models including the fruit fly, Drosophila melanogaster. High in polyphenolic content, green tea has been shown to reduce oxidative stress in part by its ability to bind free iron, a micronutrient that is both essential for and toxic to all living organisms. Due to green tea's iron-binding properties, we questioned whether green tea acts to increase the lifespan of the fruit fly by modulating iron regulators, specifically, mitoferrin, a mitochondrial iron transporter, and transferrin, found in the hemolymph of flies. Publicly available hypomorph mutants for these iron regulators were utilized to investigate the effect of green tea on lifespan and fertility. We identified that green tea could not increase the lifespan of mitoferrin mutants but did rescue the reduced male fertility phenotype. The effect of green tea on transferrin mutant lifespan and fertility were comparable to w1118 flies, as observed in our previous studies, in which green tea increased male fly lifespan and reduced male fertility. Expression levels in both w1118 flies and mutant flies, supplemented with green tea, showed an upregulation of mitoferrin but not transferrin. Total body and mitochondrial iron levels were significantly reduced by green tea supplementation in w1118 and mitoferrin mutants but not transferrin mutant flies. Our results demonstrate that green tea may act to increase the lifespan of Drosophila in part by the regulation of mitoferrin and reduction of mitochondrial iron.

Extension of Drosophila Lifespan by Rhodiola rosea Depends on Dietary Carbohydrate and Caloric Content in a Simplified Diet.

The root and rhizome extract of Rhodiola rosea has been extensively used in traditional medicine to improve physical and mental performance and to protect against stress. We, and others, have reported that R. rosea can extend lifespan in flies, worms, and yeast. We also previously found that the extract can act independently of dietary restriction (DR), a treatment that can extend lifespan in a range of model organisms. In flies, DR is implemented through a reduction in dietary yeast content. Here, we report that the ability of R. rosea extract to extend lifespan in flies is dependent on the carbohydrate and caloric content when supplemented with a simplified diet composed of yeast and sucrose. R. rosea extract elevated the sugar content in flies and down-regulated hexokinase expression, suggesting that it perturbs carbohydrate metabolism in flies. In our previous studies, bananas, barley malt, and corn syrup provided dietary carbohydrates, and R. rosea extract could extend lifespan with a range of caloric levels. We conclude that the lifespan-extending effect of R. rosea extract in flies is dependent on dietary carbohydrate and caloric contents coupled with an interaction with complex dietary components present in bananas, barley, or corn.

The impact of green tea polyphenols on development and reproduction in Drosophila melanogaster.

Although, green tea has numerous health benefits, adverse effects with excessive consumption have been reported. Using Drosophila melanogaster, a decrease in male fertility with green tea was evidenced. Here, the extent of green tea toxicity on development and reproduction was investigated. Drosophila melanogaster embryos and larvae were exposed to various doses of green tea polyphenols (GTP). Larvae exposed to 10 mg/mL GTP were slower to develop, emerged smaller, and exhibited a dramatic decline in the number of emerged offspring. GTP protected flies against desiccation but sensitized them to starvation and heat stress. Female offspring exhibited a decline in reproductive output and decreased survival while males were unaffected. GTP had a negative impact on reproductive organs in both males and females (e.g., atrophic testes in males, absence of mature eggs in females). Collectively, the data show that high doses of GTP adversely affect development and reproduction of Drosophila melanogaster.

Extension of Drosophila lifespan by cinnamon through a sex-specific dependence on the insulin receptor substrate chico.

Cinnamon is a spice commonly used worldwide to flavor desserts, fruits, cereals, breads, and meats. Numerous health benefits have been attributed to its consumption, including the recent suggestion that it may decrease blood glucose levels in people with diabetes. Insulin signaling is an integral pathway regulating the lifespan of laboratory organisms, such as worms, flies, and mice. We posited that if cinnamon truly improved the clinical signs of diabetes in people that it would also act on insulin signaling in laboratory organisms and increase lifespan. We found that cinnamon did extend lifespan in the fruit fly, Drosophila melanogaster. However, it had no effect on the expression levels of the 3 aging-related Drosophila insulin-like peptides nor did it alter sugar, fat, or soluble protein levels, as would be predicted. In addition, cinnamon exhibited no protective effects in males against oxidative challenges. However, in females it did confer a protective effect against paraquat, but sensitized them to iron. Cinnamon provided no protective effect against desiccation and starvation in females, but sensitized males to both. Interestingly, cinnamon protected both sexes against cold, sensitized both to heat, and elevated HSP70 expression levels. We also found that cinnamon required the insulin receptor substrate to extend lifespan in males, but not females. We conclude that cinnamon does not extend lifespan by improving stress tolerance in general, though it does act, at least in part, through insulin signaling.

Green tea polyphenols extend the lifespan of male drosophila melanogaster while impairing reproductive fitness.

Green tea is a popular beverage believed to have many health benefits, including a reduction in the risks of heart disease and cancer. Rich in polyphenolic compounds known as catechins, green tea and its components have been shown to increase the lifespan of various animal models, including Drosophila melanogaster. Here, we investigated the gender-specific effects of green tea on the lifespan of fruit flies and observed that green tea extended the lifespan of male flies only. This effect was found to be independent of typical aging interventions, such as dietary restriction, modulation of oxidative energy metabolism, and improved tolerance to environmental stresses. The one exception was that green tea did protect male flies against iron toxicity. Since there is an inverse correlation between lifespan and reproduction, the impact of green tea on male reproductive fitness was also investigated. We found that green tea negatively impacted male fertility as shown by a reduced number of offspring produced and increased mating latency. We further identified that the lifespan extension properties of green tea was only observed in the presence of females which alludes to a reproductive (or mating) dependent mechanism. Our findings suggest that green tea extends the lifespan of male flies by inhibiting reproductive potential, possibly by limiting iron uptake. To our knowledge, our study is the first to report the negative impact of green tea on Drosophila male reproduction. Our results also support previous studies that suggest that green tea might have a negative effect on reproductive fitness in humans.

Extension of Drosophila lifespan by Rhodiola rosea through a mechanism independent from dietary restriction.

Rhodiola rosea has been extensively used to improve physical and mental performance and to protect against stress. We, and others, have reported that R. rosea can extend lifespan in flies, worms, and yeast. However, its molecular mechanism is currently unknown. Here, we tested whether R. rosea might act through a pathway related to dietary restriction (DR) that can extend lifespan in a range of model organisms. While the mechanism of DR itself is also unknown, three molecular pathways have been associated with it: the silent information regulator 2 (SIR2) proteins, insulin and insulin-like growth factor signaling (IIS), and the target of rapamycin (TOR). In flies, DR is implemented through a reduction in dietary yeast content. We found that R. rosea extract extended lifespan in both sexes independent of the yeast content in the diet. We also found that the extract extended lifespan when the SIR2, IIS, or TOR pathways were genetically perturbed. Upon examination of water and fat content, we found that R. rosea decreased water content and elevated fat content in both sexes, but did not sensitize flies to desiccation or protect them against starvation. There were some sex-specific differences in response to R. rosea. In female flies, the expression levels of glycolytic genes and dSir2 were down-regulated, and NADH levels were decreased. In males however, R. rosea provided no protection against heat stress and had no effect on the major heat shock protein HSP70 and actually down-regulated the mitochondrial HSP22. Our findings largely rule out an elevated general resistance to stress and DR-related pathways as mechanistic candidates. The latter conclusion is especially relevant given the limited potential for DR to improve human health and lifespan, and presents R. rosea as a potential viable candidate to treat aging and age-related diseases in humans.

Extension of Drosophila lifespan by Rosa damascena associated with an increased sensitivity to heat.

Rosa damascena, or Damask rose, is a rose hybrid commonly harvested for rose oil used in perfumery and for rose water used to flavor food. The petal extract of R. damascena was recently found to decrease Drosophila melanogaster mortality without impairing reproductive fitness or metabolic rate. Here, we report that R. damascena extended both mean and maximum lifespan of the fly. The extract also protected against oxidative stress in flies, predominantly in females. However, it did not alter mitochondrial respiration or content, superoxide production, or the major antioxidant defenses, superoxide dismutase and catalase. The extract increased survival in both sexes when exposed to reduced iron, though surprisingly, it sensitized both sexes to heat stress (survival at 37°C), and appeared to down-regulate the major heat shock protein HSP70 and the small mitochondrial heat shock protein HSP22, at 25°C and after heat shock (4 h at 37°C). We hypothesize that R. damascena extends lifespan by protecting against iron, which concomitantly leads to decreased HSP expression and compromising heat tolerance.

Decreased mitochondrial superoxide levels and enhanced protection against paraquat in Drosophila melanogaster supplemented with Rhodiola rosea.

The root extract from Rhodiola rosea has been reported to have numerous health benefits in human and animal studies. Its molecular mechanism is currently unknown; however, it has been suggested to act as an antioxidant. This study found that a formulation of R. rosea extract, SHR-5, from the Swedish Herbal Institute (SHI) could extend both mean (24% in both sexes) and maximum (16% in males and 31% in females) life span in Drosophila melanogaster when compared to controls. It also found that it lowered mitochondrial superoxide levels and afforded elevated protection against the superoxide generator paraquat in both sexes. The extract SHR-5 did not alter the activities of the major antioxidant enzymes, the superoxide dismutases or catalase, nor did it afford protection against H(2)O(2) or soluble iron. These results present a decrease in endogenous superoxide levels as a possible mode of action for the root extract of R. rosea.

Protection of human cultured cells against oxidative stress by Rhodiola rosea without activation of antioxidant defenses.

Rhodiola rosea root has been long used in traditional medical systems in Europe and Asia as an adaptogen to increase an organism's resistance to physical stress. Recent research has demonstrated its ability to improve mental and physical stamina, to improve mood, and to help alleviate high-altitude sickness. We have also recently found that R. rosea is able to extend the life span of Drosophila melanogaster. The mode of action of R. rosea is currently unknown; it has been suggested by some to act as an antioxidant, whereas others have argued that it may actually be a pro-oxidant and act through a hormetic mechanism. We found that R. rosea supplementation could protect cultured cells against ultraviolet light, paraquat, and H(2)O(2). However, it did not alter the levels of the major antioxidant defenses nor did it markedly activate the antioxidant response element or modulate heme-oxygenase-1 expression levels at relevant concentrations. In addition, R. rosea extract was not able to significantly degrade H(2)O(2) in vitro. These results suggest that in human cultured cells R. rosea does not act as an antioxidant and that its mode of action cannot be sufficiently explained through a pro-oxidant hormetic mechanism.

Adenine nucleotide translocator 1 deficiency increases resistance of mouse brain and neurons to excitotoxic insults.

The mitochondrial adenine nucleotide translocators (Ant) are bi-functional proteins that transport ADP and ATP across the mitochondrial inner membrane, and regulate the mitochondrial permeability transition pore (mtPTP) which initiates apoptosis. The mouse has three Ant isoforms: Ant1 expressed in heart, muscle, and brain; Ant2 expressed in all tissues but muscle; and Ant4 expressed primarily in testis. Ant1-deficient mice manifest muscle and heart but not brain pathology. Brain Ant1 is induced by stress, while Ant2 is not. Ant1-deficient mice are resistant to death induced by systemic exposure to the brain excitotoxin, kainic acid (KA), and their hippocampal and cortical neurons are significantly more resistant to neuronal death induced by glutamate, KA, and etoposide. The mitochondrial membrane potential of Ant1-deficient brain mitochondria is increased and the mtPTP is more resistance to Ca(++) induced permeability transition. Hence, Ant1-deficiency may protect the brain from excitotoxicity by desensitizing the mtPTP and by blocking the pro-apoptotic induction of Ant1 by stress.

Life extension through neurofibromin mitochondrial regulation and antioxidant therapy for neurofibromatosis-1 in Drosophila melanogaster.

We investigated the pathophysiology of neurofibromatosis-1 (NF1) in Drosophila melanogaster by inactivation or overexpression of the NF1 gene. NF1 gene mutants had shortened life spans and increased vulnerability to heat and oxidative stress in association with reduced mitochondrial respiration and elevated reactive oxygen species (ROS) production. Flies overexpressing NF1 had increased life spans, improved reproductive fitness, increased resistance to oxidative and heat stress in association with increased mitochondrial respiration and a 60% reduction in ROS production. These phenotypic effects proved to be modulated by the adenylyl cyclase/cyclic AMP (cAMP)/protein kinase A pathway, not the Ras/Raf pathway. Treatment of wild-type D. melanogaster with cAMP analogs increased their life span, and treatment of NF1 mutants with metalloporphyrin catalytic antioxidant compounds restored their life span. Thus, neurofibromin regulates longevity and stress resistance through cAMP regulation of mitochondrial respiration and ROS production, and NF1 may be treatable using catalytic antioxidants.

Oxidative damage and aging: spotlight on mitochondria.

Whereas free radical damage has been proposed as a key component in the tissue degeneration associated with aging, there has been little evidence that free radical damage limits life span in mammals. The current research shows that overexpression of the antioxidant enzyme catalase in mitochondria can extend mouse life span. These results highlight the importance of mitochondrial damage in aging and suggest that when targeted appropriately, boosting antioxidant defenses can increase mammalian life span.

Extension of mouse lifespan by overexpression of catalase.

The free radical theory of aging was originally proposed 50 years ago, and is arguably the most popular mechanism explaining the aging process. According to this theory, aging results from the progressive decline in organ function due to the damage generated by reactive oxygen species (ROS). These chemical species are a normal part of metabolism, and a group of enzymes exists to protect cells against their toxic effects. One of these species is hydrogen peroxide (H(2)O(2)), which can be degraded by catalase. To determine the role of hydrogen peroxide in aging and its importance in different subcellular compartments, transgenic mice were developed with increased catalase activities localized to the peroxisome (PCAT), nucleus (NCAT), or mitochondrion (MCAT). The largest effect on lifespan was found in MCAT animals, with a 20% increase in median lifespan and a 10% increase in the maximum lifespan. A more modest effect was seen in PCAT animals, and no significant change was found in NCAT animals. Upon further examination of the MCAT mice, it was found that H(2)O(2) production and H(2)O(2)-induced aconitase inactivation were attenuated, oxidative damage and the development of mitochondrial deletions were reduced, and cardiac pathology and cataract development were delayed. These results are consistent with a role of H(2)O(2) in the development of pathology and in the limitation of mouse lifespan. They also demonstrate the importance of mitochondria as a source, and possible target, of ROS.

Extension of murine life span by overexpression of catalase targeted to mitochondria.

To determine the role of reactive oxygen species in mammalian longevity, we generated transgenic mice that overexpress human catalase localized to the peroxisome, the nucleus, or mitochondria (MCAT). Median and maximum life spans were maximally increased (averages of 5 months and 5.5 months, respectively) in MCAT animals. Cardiac pathology and cataract development were delayed, oxidative damage was reduced, H2O2 production and H2O2-induced aconitase inactivation were attenuated, and the development of mitochondrial deletions was reduced. These results support the free radical theory of aging and reinforce the importance of mitochondria as a source of these radicals.