Fig. 6: AICAR-mediated AMPK activation rescues metabolite-induced dopaminergic neurodegeneration.

a The effect of eat-3 RNAi on ATP levels in pink-1(tm1779) mutant animals after exposure of solvent (EtAc) or metabolite. ATP content was measured in young adult nematodes using a luciferase-based assay. Values are mean ± S.E.M.; n = 3 independent samples with 100 worms in each; one-way ANOVA with Tukey’s post hoc test for multiple comparisons. ****P < 0.0001. b Reduction of either aak-2 or mff-1 enhanced DA neurotoxicity with or without metabolite in comparison with EV solvent control. Data represented as mean ± S.E.M.; n = 30 animals per replicate, three independent replicates; one-way ANOVA with Tukey’s post hoc test for multiple comparisons. **P < 0.005. c A timeline representing an experimental paradigm depicting the relative length of S. ven metabolite exposure and AICAR treatment. The abbreviations L1–L4 are the larval stages of C. elegans, and the ‘young adult’ designations represent days post-hatching. F1 animals were treated with either RNAi and/or S. ven metabolite from hatching to the day of analysis; neurodegeneration assays were performed at day 9. Animals were treated with 1 mM AICAR from hatching until day 4. d Animals expressing only GFP in the DA neurons treated with AICAR (alone) displayed enhanced DA neurodegeneration compared to solvent controls; however, metabolite-induced neurotoxicity was reduced by AICAR treatment. Furthermore, AICAR rescued neurotoxicity caused by pink-1(tm1779) in comparison to non-AICAR treated (solvent) animals with pink-1 mutation. AICAR did not rescue DA neuron cell death from the combined stress of metabolite and pink-1. Data are presented as mean ± S.E.M.; n = 30 animals per replicate, three independent replicates; one-way ANOVA with Tukey’s post hoc test for multiple comparisons. *P < 0.05, ***P < 0.001. e AICAR-mediated AMPK activation was sufficient to protect neurodegeneration caused by eat-3 deficiency (RNAi) alone or with metabolite, however, it could not reduce neurotoxicity in the absence of pink-1 function (tm1779) and eat-3 RNAi together. Data represented as mean ± S.E.M.; n = 30 animals per replicate, three independent replicates; one-way ANOVA with Tukey’s post hoc test for multiple comparisons. *P < 0.05, **P < 0.01. f AICAR-mediated AMPK activation failed to attenuate neurotoxicity from drp-1 (RNAi) depletion in the GFP only or pink-1(tm1779) mutant background; however, AICAR suppressed neurotoxicity in the pink-1 mutant background in combination with metabolite exposure. These data are presented as mean ± S.E.M.; n = 30 animals per replicate, three independent replicates; one-way ANOVA with Tukey’s post hoc test for multiple comparisons. *P < 0.05.