Alleviation of neuronal energy deficiency by mTOR inhibition as a treatment for mitochondria-related neurodegeneration

• Published in: eLife Vol. 5
• Main Authors: Zheng, Xinde, Boyer, Leah, Jin, Mingji, Kim, Yongsung, Fan, Weiwei, Bardy, Cedric, Berggren, Travis, Evans, Ronald M, Gage, Fred H, Hunter, Tony
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 23.03.2016; eLife Sciences Publications Ltd; eLife Sciences Publications, Ltd
• Subjects: Adenosine Triphosphate - metabolism; Apoptosis; ATP; ATP synthase; Bioenergetics; Cells, Cultured; Degeneration; Health aspects; Human Biology and Medicine; Humans; iPS disease modeling; Kinases; maternally inherited Leigh syndrome; Mitochondria; Mitochondria - metabolism; Mitochondrial DNA; Mutation; Nervous system; Neural stem cells; Neurodegeneration; Neurodegenerative Diseases - pathology; Neurons - drug effects; Neurons - physiology; Neuroprotective Agents - metabolism; Oxidative phosphorylation; Phagocytosis; Phosphorylation; Prevention; Protein biosynthesis; Protein Biosynthesis - drug effects; Rapamycin; Sirolimus - metabolism; TOR protein; TOR Serine-Threonine Kinases - antagonists & inhibitors; Toxicity; human biology; iPS disease modeling; maternally inherited Leigh syndrome; mitochondria; medicine; ATP; human; rapamycin
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/elife.13378

mTOR inhibition is beneficial in neurodegenerative disease models and its effects are often attributable to the modulation of autophagy and anti-apoptosis. Here, we report a neglected but important bioenergetic effect of mTOR inhibition in neurons. mTOR inhibition by rapamycin significantly preserves neuronal ATP levels, particularly when oxidative phosphorylation is impaired, such as in neurons treated with mitochondrial inhibitors, or in neurons derived from maternally inherited Leigh syndrome (MILS) patient iPS cells with ATP synthase deficiency. Rapamycin treatment significantly improves the resistance of MILS neurons to glutamate toxicity. Surprisingly, in mitochondrially defective neurons, but not neuroprogenitor cells, ribosomal S6 and S6 kinase phosphorylation increased over time, despite activation of AMPK, which is often linked to mTOR inhibition. A rapamycin-induced decrease in protein synthesis, a major energy-consuming process, may account for its ATP-saving effect. We propose that a mild reduction in protein synthesis may have the potential to treat mitochondria-related neurodegeneration.