Figure 1. Genes responsible for ether lipid biosynthesis are necessary for biguanide-induced lifespan extension.
(A) C. elegans ether lipid synthesis is catalyzed by three enzymes: fatty acyl reductase FARD-1, acyltransferase ACL-7, and alkylglycerone phosphate synthase ADS-1 (adapted from Figure 1 of Shi et al., 2016 and Dean and Lodhi, 2018). The latter two are localized to the peroxisomal lumen. (B–D) Missense, loss-of-function mutations in fard-1 (B), acl-7 (C), and ads-1 (D) in C. elegans suppress phenformin-induced lifespan extension. (E–G) A deficiency of ether lipid synthesis in fard-1 (E), acl-7 (F), and ads-1 (G) worm mutants blunts metformin-induced lifespan extension. Results are representative of three biological replicates. *, p<0.05; **, p<0.01; ***, p<0.001; ****, p<0.0001 by log-rank analysis. Note that (B–D) and (E–G) contain the same wild-type (wt) controls as they are visualized from the same replicate of the study. See also Figure 1—figure supplement 1 and refer to Supplementary file 1 for tabular survival data and biological replicates. (H–I) Normalized concentrations of phenformin (H) and metformin (I) in vehicle, 4.5 mM phenformin, or 50 mM metformin-treated wt C. elegans versus fard-1, acl-7, and ads-1 mutants. n=3 biological replicates; ***, p<0.004 by two-tailed Student’s t-test with Bonferroni correction for multiple hypothesis testing. Box represents 75th/25th percentiles, while whisker represents higher/lower hinge ± [1.5 * interquartile range (IQR)].
Figure 1—figure supplement 1. Reduced function of genes responsible for ether lipid biosynthesis partially suppresses biguanide effects of growth and lifespan without affecting biguanide levels.
Figure 1—figure supplement 2. The use of 5-fluoro-2′-deoxyuridine (FUdR) in lifespan analyses does not impact the observed epistases between the ether lipid machinery and biguanide-mediated lifespan extension.
