Pro-autophagic polyphenols and polyamines for longevity

The present project prolongs the long-term efforts of the laboratory headed by Frank Madeo (University of Graz, Graz, Austria) to devise longevity-promoting strategies and to understand their molecular mechanisms. Indeed, the Madeo lab was the first to discover that spermidine can promote longevity from yeast to human cells through autophagy induction. Based on our experience and the literature, we postulate that ideal candidate anti-aging agents (CAAAs) should be naturally contained in health-related food items (as it is the case for the polyphenol resveratrol and the polyamine spermidine), act as caloric restriction mimetics, and induce autophagy without triggering toxic organellar stress, ultimately prolonging lifespan in various model organisms. Based on these premises, we propose a series of functional screens that compose a pipeline for the rapid identification and mechanistic characterization of CAAAs with a high potential to become true AAAs. For this purpose, we will first create a collection of chemically defined and commercially available agents that are contained in health-relevant food items or possess structural analogies to known AAAs (task 1). We will then perform autophagy screens in yeast and human cell lines upon treatment with potential CAAAs to establish a CAAA shortlist (task 2), from which we will measure the acute apoptotic or necrotic death of human and yeast cells exposed to identified CAAAs and determine organellar stress and DNA damage using human biosensor cell lines to exclude cytotoxic, genotoxic and potentially pro-inflammatory agents (task 3). The resulting CAAAs will undergo further characterization for their capacity to improve longevity in chronological aging experiments in yeast (task 4). CAAAs increasing yeast longevity will be further tested for their capacity to extend the lifespan of fruit flies (task 5). CAAAs that have been filtered through all the preceding steps will then be evaluated for their efficiency to induce autophagy and mediate organ protection in mice, followed by longevity experiments in old mice (task 6). Using a proteomic approach, we will identify possible regulators involved in the lifespan-extending effects of each CAAA validated in tasks 1-6 and perform mechanistic studies to explore if these proteins and/or autophagy are necessary to increase lifespan for a given CAAA.(task 7). Altogether, a compound library (task 1) will be the basis for a pipeline providing criteria for the inclusion or progressive exclusion of CAAAs into a shortlist (tasks 2-6) that will be analyzed to obtain mechanistic insights on the potential mode of action of CAAAs (task 7).

The prevalence of age-related pathologies (for example, Alzheimers and Parkinsons disease, cardiovascular disorders, or cancer) is increasing in an alarming manner. This represents a major burden for patients and their families, and poses not only a social but also an economic hazard that urgently needs appropriate interventions. The permanent reduction of calorie intake (without malnutrition) has proven effective, but most individuals cannot observe or follow a corresponding lifestyle. Thus, pharmacological alternatives are warranted, and the search for drugs that potentially revert age-associated decline has become a major topic in biological sciences. The aim of this project was to find new natural substances with the capacity to counteract aging. For that purpose we designed a screening method in the bakers yeast Saccharomyces cerevisiae, an established model organism to study aging, and tested 200 compounds for their capacity to extend lifespan. Our screen revealed 4,4`-dimethoxychalcone (DMC) as the top hit. We further validated these results showing that DMC extends the lifespan in multicellular organisms (worms, flies) and slows senescence the age-associated disruption of cell function - in cultured human cells. Furthermore, we demonstrated that DMC promotes cardioprotection in mice subjected to myocardial ischemia (decreased blood flow in the heart muscle eventually resulting in an infarct). These effects are mainly mediated by the induction of autophagy, an important cellular cleanup process causally linked to the beneficial effects of caloric restriction. Autophagy protects cells against aging and cell stress by eliminating defective organelles and cell components (like proteins or protein aggregates) that otherwise would impair cell function. The ability of an organism to induce autophagy decreases with age, and DMC can revert this, thereby extending lifespan. Our work further revealed the molecular mechanisms behind DMC mediated autophagy induction to be mediated by a specific transcription factor family (GATA). Future work will yield at exploring chemical derivatives of DMC with potentially higher potency. Besides, this project has revealed a number of other candidates that will be also further analyzed in the future. In conclusion, we have successfully established and validated an effective screening tool to identify conserved anti-aging compounds with conserved activity throughout species.