Extended Data Fig. 2: LCA activates the lysosomal AMPK pathway downstream of the low glucose sensor aldolase-TRPV axis.
From: Lithocholic acid binds TULP3 to activate sirtuins and AMPK to slow down ageing
a, Glucose decline in CR mice does not suffice to cause AMPK activation. Levels of blood glucose (upper panel), muscle FBP (lower panel), and the activity of muscle AMPK (middle panel) were determined in mice subjected to starvation for 4 h, 8 h, 12 h, 16 h, and 20 h, or CR, at indicated times of the day. Results are shown as mean ± s.e.m.; n = 5 (blood glucose of CR and starvation groups) or 4 (others) mice for each time point, and P value by two-way ANOVA followed by Tukey’s test. b, CR leads to a constant activation of AMPK in muscle. Mice were subjected to CR for 4 months, followed by determination of the muscular AMPK activation at different times of the day. c-h, LCA triggers the lysosomal AMPK pathway downstream of aldolase and TRPVs. MEFs with knockdown of aldolase A-C (ALDO-KD) and re-introduced with ALDOA-D34S that mimics high glucose/FBP condition10 (c-e), or MEFs with TRPV1-4 knockout (f-h; TRPV-QKO, blocking signalling from low glucose to AMPK activation12), were incubated in normal (c, f-h) or glucose-free (c-e) medium (Glc starvation) containing 1 μM LCA for 4 h, followed by determination for AMPK activation (c, f), v-ATPase inhibition (d, g), and lysosomal localization of AXIN (e, h). Statistical analysis data are shown as mean ± s.e.m., where d and g were normalized to the DMSO group; n = 25 (ALDOA-WT + DMSO and ALDOA-D34S + DMSO of d), 21 (TRPV-QKO + LCA of g and TRPV-QKO + LCA of h), 23 (ALDOA-WT + LCA of e and TRPV-QKO + DMSO of h), 24 (ALDOA-WT + DMSO of e), or 20 (others) cells; and P value by two-sided Student’s t-test (d, ALDOA-WT), two-sided Student’s t-test with Welch’s correction (d, ALDOA-D34S; and g), or two-way ANOVA followed by Tukey’s test (e). Experiments in this figure were performed three times.
