Automated lifespan determination across Caenorhabditis strains and species reveals assay-specific effects of chemical interventions

Abstract

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.Electronic supplementary materialThe online version of this article (10.1007/s11357-019-00108-9) contains supplementary material, which is available to authorized users.

Phenotypic Screening in C. elegans as a Tool for the Discovery of New Geroprotective Drugs

“…For example, in a study on the effect of α-ketoglutarate on lifespan in C. elegans, it was observed that the stock solution of α-ketoglutarate had a pH of 1.56, which might overwhelm the buffering capacity of the NGM, leading to an abnormally low pH of the medium. However, adjustment of the pH by titration with NaOH did not influence the lifespan results obtained by α-ketoglutarate treatment [220].…”

“…For instance, thioflavin T extends lifespan of C. elegans in manual assays, but in the lifespan machine thioflavin T shortened lifespan significantly. The adverse effect of thioflavin T on lifespan in liquid cultures was reversed when a blue/UV light filter was installed on the lifespan machine [220]. Another problem is the heat produced by the scanner.…”

“…The C. elegans Interventions Testing Program (CITP) uses Lifespan Machines for increased throughput in compound screening (https://citp.squarespace.com/). Thus far, this program, which was initiated in 2013, has evaluated more than 20 compounds and found several compounds that increased lifespan in at least one of the tested strains [186,220,230,[279][280][281].…”

A simplified design for the C. elegans lifespan machine

“…We performed all animal husbandry at 20°C on NGM plates seeded with E. coli OP50-1 as a mono-cultured food source. We conducted survival assays as previously published for either manual or lifespan machine-assisted studies [ 6 , 9 ]. In brief, we grew synchronized cohorts of animals until day one of adulthood.…”

Spectrum of Mesenchymal–Epithelial Transition Aberrations and Potential Clinical Implications: Insights From Integrative Pancancer Analysis

“…The clinical data were used to perform the survival association analysis for MET alteration or for MET amplification status. In addition, we mainly evaluated several survival indexes, such as overall survival (OS) and progression-free survival (PFS) (19)(20)(21)(22). The association between MET expression and patients' OS and PFS was analyzed using the Kaplan-Meier Plotter 5 , an open source platform that can be used to assess the effect of genes on patient survival.…”