The Caenorhabditis Intervention Testing Program (CITP) is an NIH-funded research consortium of investigators who conduct analyses at three independent sites to identify chemical interventions that reproducibly promote health and lifespan in a robust manner. The founding principle of the CITP is that compounds with positive effects across a genetically diverse panel of Caenorhabditis species and strains are likely engaging conserved biochemical pathways to exert their effects. As such, interventions that are broadly efficacious might be considered prominent compounds for translation for pre-clinical research and human clinical applications. Here, we report results generated using a recently streamlined pipeline approach for the evaluation of the effects of chemical compounds on lifespan and health. We studied five compounds previously shown to extend C. elegans lifespan or thought to promote mammalian health: 17α-estradiol, acarbose, green tea extract, nordihydroguaiaretic acid, and rapamycin. We found that green tea extract and nordihydroguaiaretic acid extend Caenorhabditis lifespan in a species-specific manner. Additionally, these two antioxidants conferred assay-specific effects in some studies-for example, decreasing survival for certain genetic backgrounds in manual survival assays in contrast with extended lifespan as assayed using automated C. elegans Lifespan Machines. We also observed that GTE and NDGA impact on older adult mobility capacity is dependent on genetic background, and that GTE reduces oxidative stress resistance in some Caenorhabditis strains. Overall, our analysis of the five compounds supports the general idea that genetic background and assay type can influence lifespan and health effects of compounds, and underscores that lifespan and health can be uncoupled by chemical interventions.

Metformin, the most commonly prescribed anti-diabetes medication, has multiple reported health benefits, including lowering the risks of cardiovascular disease and cancer, improving cognitive function with age, extending survival in diabetic patients, and, in several animal models, promoting youthful physiology and lifespan. Due to its longevity and health effects, metformin is now the focus of the first proposed clinical trial of an anti-aging drug-the Targeting Aging with Metformin (TAME) program. Genetic variation will likely influence outcomes when studying metformin health effects in human populations. To test for metformin impact in diverse genetic backgrounds, we measured lifespan and healthspan effects of metformin treatment in three Caenorhabditis species representing genetic variability greater than that between mice and humans. We show that metformin increases median survival in three C. elegans strains, but not in C. briggsae and C. tropicalis strains. In C. briggsae, metformin either has no impact on survival or decreases lifespan. In C. tropicalis, metformin decreases median survival in a dose-dependent manner. We show that metformin prolongs the period of youthful vigor in all C. elegans strains and in two C. briggsae strains, but that metformin has a negative impact on the locomotion of C. tropicalis strains. Our data demonstrate that metformin can be a robust promoter of healthy aging across different genetic backgrounds, but that genetic variation can determine whether metformin has positive, neutral, or negative lifespan/healthspan impact. These results underscore the importance of tailoring treatment to individuals when testing for metformin health benefits in diverse human populations.

agonist obeticholic acid does not robustly extend lifespan in nematodes Mackenzie L Morshead1, Christine A Sedore2, E Grace Jones2, David Hall1, W Todd Plummer1, Theo Garrett1, Mark Lucanic1, Max Guo3, Monica Driscoll4, Patrick C Phillips2 and Gordon Lithgow1§ 1The Buck Institute for Research on Aging, Novato, California 94945, USA 2Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon 97403, USA 3Division of Aging Biology, National Institute on Aging, Bethesda, Maryland 20892, USA 4Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854, USA §To whom correspondence should be addressed: glithgow@buckinstitute.org

The goal of the Caenorhabditis Intervention Testing Program is to identify robust and reproducible pro-longevity interventions that are efficacious across genetically diverse cohorts in the Caenorhabditis genus. The project design features multiple experimental replicates collected by three different laboratories. Our initial effort employed fully manual survival assays. With an interest in increasing throughput, we explored automation with flatbed scanner-based Automated Lifespan Machines (ALMs). We used ALMs to measure survivorship of 22 Caenorhabditis strains spanning three species. Additionally, we tested five chemicals that we previously found extended lifespan in manual assays. Overall, we found similar sources of variation among trials for the ALM and our previous manual assays, verifying reproducibility of outcome. Survival assessment was generally consistent between the manual and the ALM assays, although we did observe radically contrasting results for certain compound interventions. We found that particular lifespan outcome differences could be attributed to protocol elements such as enhanced light exposure of specific compounds in the ALM, underscoring that differences in technical details can influence outcomes and therefore interpretation. Overall, we demonstrate that the ALMs effectively reproduce a large, conventionally scored dataset from a diverse test set, independently validating ALMs as a robust and reproducible approach toward aging-intervention screening.

Limiting the debilitating consequences of ageing is a major medical challenge of our time. Robust pharmacological interventions that promote healthy ageing across diverse genetic backgrounds may engage conserved longevity pathways. Here we report results from the Caenorhabditis Intervention Testing Program in assessing longevity variation across 22 Caenorhabditis strains spanning 3 species, using multiple replicates collected across three independent laboratories. Reproducibility between test sites is high, whereas individual trial reproducibility is relatively low. Of ten pro-longevity chemicals tested, six significantly extend lifespan in at least one strain. Three reported dietary restriction mimetics are mainly effective across C. elegans strains, indicating species and strain-specific responses. In contrast, the amyloid dye ThioflavinT is both potent and robust across the strains. Our results highlight promising pharmacological leads and demonstrate the importance of assessing lifespans of discrete cohorts across repeat studies to capture biological variation in the search for reproducible ageing interventions.

The Caenorhabditis Intervention Testing Program \(CITP) seeks to identify compounds that robustly improve lifespan and/or attenuate age-dependent declines in health across a genetically diverse set of Caenorhabditis species and strains.A core mission of the CITP is to collect data that will inform on the reproducibility of our experimental results.To achieve this, multiple replicates of each experiment are performed by each of three groups at separate laboratory sites.In an effort to limit non-biological confounding factors that may in uence the reproducibility of these results, we sought to minimize differences in experimental conditions across the individual laboratories.This led to the development and utilization of a set of standardized protocols that describe speci c methods for nematode maintenance and culture as well as detailed experimental procedures.All laboratories of the CITP are tasked with strict adherence to protocols.Here we provide several protocols that describe the CITP standard operating practices for bacterial cultures, media preparation and strain handing as well as assays for quantifying the development rate, fertility and lifespan of hermaphroditic Caenorhabditis strains.Individual components of these methods were not tested for their effects on outcomes and are not suggested to be best practices.However our consideration of the methodological variability available for even these simple assays does highlight the potential for differences in methodology to in uence experimental reproducibility.