Research Paper Volume 2, Issue 7 pp 393—414

Chemical genetic screen identifies lithocholic acid as an anti-aging compound that extends yeast chronological life span in a TOR-independent manner, by modulating housekeeping longevity assurance processes

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Figure 7. In reproductively mature WT yeast that entered the non-proliferative stationary (ST) phase under CR, LCA modulates mitochondrial morphology and functions, enhances stress resistance, attenuates mitochondria-controlled apoptosis, and increases stability of nuclear and mitochondrial DNA. (A) Percent of WT cells grown in medium with or without LCA and exhibiting a tubular mitochondrial network or fragmented mitochondria. Mitochondria were visualized by indirect immunofluorescence microscopy using monoclonal anti-porin primary antibodies and Alexa Fluor 568-conjugated goat anti-mouse IgG secondary antibodies. (B - D) Oxygen consumption by WT cells grown in medium with or without LCA (B), their mitochondrial membrane potential ΔΨ (C) and their ROS levels (D). ΔΨ and ROS were visualized in living cells by fluorescence microscopy using fluorescent dyes Rhodamine 123 or Dihydrorhodamine 123, respectively. (E) The resistance of WT cells pre-grown in medium with or without LCA to chronic oxidative, thermal and osmotic stresses. (F) Viability of WT cells pre-grown in medium with or without LCA and then treated for 1 h with hydrogen peroxide or acetic acid (AcOH) to induce mitochondria-controlled apoptosis. (G- I) The frequencies of rho- and rho0mutations in mitochondrial DNA (G), rib2 and rib3 mutations in mitochondrial DNA (H), and of can1 (Canr) mutations in nuclear DNA (I) of WT cells grown in medium with or without LCA. Data in A - D and F - I are presented as means ± SEM (n = 4-17; ***p < 0.001; **p < 0.01). WT cells grown on 0.2% glucose in the presence or absence of LCA were taken for analyses at day 7, when they reached reproductive maturation by entering into ST phase.