Figure 8: Increased BCAAs act through neuronal LET-363/mTOR and peripheral DAF-7/TGFβ signaling to extend lifespan.

(a) Shows lifespan data of wild-type nematodes without treatment (black), as well as, exposure to L-alanine (grey, 5 mM) and L-leucine (blue, 5 mM) for their entire adult lifespan, maintained on non-metabolizing bacteria (P=0.24 for L-ala and P<0.0001 for L-leu both versus control, log-rank test, n=3). (b,c) Show effects of bcat-1 RNAi (red) on lifespan in strains mutant for (b) hsf-1 (P=0.67, log-rank test, n=3) and (c) daf-16 (P<0.001, log-rank test, n=3). (d) Depicts the effects of the mTOR-inhibitor rapamycin (100 μM) on wild-type worms (grey versus black) versus the lack of effect of non-neuronal bcat-1 RNAi in the presence of rapamycin (100 μM), all on lifespan (P<0.05 for control RNAi/rapamycin versus control RNAi/DMSO, P=0.07 for bcat-1 RNAi/rapamycin versus control RNAi/rapamycin, P<0.0001 for bcat-1 RNAi/rapamycin versus bcat-1 RNAi/DMSO, P<0.0001 for bcat-1 RNAi/DMSO versus control RNAi/DMSO, log-rank test, n=3). (e) Depicts the effects of neuronal bcat-1 RNAi on lifespan in the presence (purple) and absence (red) of neuronal RNAi against let-363/mTOR (P=45 for control/let-363 RNAi versus control RNAi, P<0.05 for control/let-363 RNAi versus let-363/bcat-1 RNAi, P<0.0001 for control/bcat-1 RNAi versus let-363/bcat-1 RNAi, P<0.0001 for control RNAi versus control/bcat-1 RNAi, log-rank test, n=3). (f,g) Depict the lack of effect of (f) peripheral bcat-1 RNAi (P=0.73, log-rank test, n=3) and (g) L-leucine supplementation (P=0.96, log-rank test, n=3) on an ASI-ablated reporter strain. (h–j) Show the lack of effect of bcat-1 RNAi on strains mutant for (h) daf-7 (P=0.15, log-rank test, n=3) and (i) daf-1 (P=0.84, log-rank test, n=3), as well (j) in the co-presence (purple) or absence (red) of RNAi against daf-4 (P=0.8 for control/bcat-1 RNAi versus daf-4/bcat-1 RNAi, P<0.0001 for all treatments versus control, log-rank test, n=3). For P-values and number of repetitions see Supplementary Table 4.