Fig. 7: The breakdown of the ER-mitochondria calcium crosstalk triggers ISCs aging due to defective autophagy. | Nature Communications

Fig. 7: The breakdown of the ER-mitochondria calcium crosstalk triggers ISCs aging due to defective autophagy.

From: Restoring calcium crosstalk between ER and mitochondria promotes intestinal stem cell rejuvenation through autophagy in aged Drosophila

Fig. 7

a Quantification of relative ERCa2+ levels in ISCs with indicated genotypes and conditions at different ages. NF, normal food; Stv, starvation. Data show mean ± S.E.M (n = 150, 161, 109, 122, 159 and 110 cells, from left to right) based on two-way ANOVA with Tukey’s multiple comparison test. ****P  <  0.0001. b, c Quantifications of the number and intensity of MAM-GFP positive vesicles in ISCs with indicated genotypes and conditions at different ages. Data show mean ± S.E.M (n = 116, 120, 121, 124, 128 and 117 cells, from left to right) based on two-way ANOVA with Tukey’s multiple comparison test. *P  <  0.05 and ****P  <  0.0001. d, e Quantifications of the number of Ref(2)P-GFP (d) and mCherryATG8 (e) positive puncta in ISCs with indicated conditions and genotypes at different ages. Data show mean ± S.E.M (n = 84, 61, 78, 79 cells in (d) and n = 123, 93, 78, 154, 147, 138 cells in (e), from left to right) based on two-way ANOVA with Tukey’s multiple comparison test. ****P  <  0.0001. f Quantification of the intensity of AMPKSPARK signals in ISCs with indicated genotypes at different ages. Data show mean ± S.E.M (n = 96, 93, 107 and 110 cells, from left to right) based on two-way ANOVA with Tukey’s multiple comparison test. ***P  < 0.001 and ****P  <  0.0001. g Quantification of the number of mCherryATG8a positive puncta in aged ISCs (30 d) with indicated genotypes. Data show mean ± S.E.M (n = 96, 74 and 70 cells, from left to right) based on one-way ANOVA with Tukey’s multiple comparison test. ****P  <  0.0001. h Model schematic: in young animal ISCs, calcium oscillations in MERC were maintained by the positive cycle formed by MitoCa2+-IP3R-MERC. In short, increasing MitoCa2+ influx by MCU overexpressing lead to the activation of IP3R, which then promote calcium release from the ER and formed oscillations in MERC which is maintained by complexes such as VAPB-PTPIP51 and IP3R-VDAC for the initiation of autophagy independent of AMPK. In aged ISCs, the MitoCa2+/IP3R/MERC cycle was disrupted, leading to impaired autophagy. Autophagosomes are indicated by double membrane vesicles. Each experiment was repeated for 3 times (a–g). See Supplementary Table 1 for genotypes. Source data are provided as a Source Data file.

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