Short-Term Starvation Activates AMPK, Restores Mitochondrial PolyP, but Doesn’t Reverse Neuronal Senescence
SUMMARY: Mitochondrial polyP depletion exacerbates neuronal senescence; dietary restriction activates AMPK but doesn't reverse senescence in affected neurons. KEY FINDINGS: Neuronal senescence significantly contributes to neurodegenerative disorders and aging. Dysregulated mitochondrial function plays a pivotal role in neuronal senescence. Dietary restriction shows promise in mitigating neuronal senescence through mitochondrial function preservation. Inorganic polyphosphate (polyP) is crucial for mitochondrial physiology and bioenergetics. Depletion of mitochondrial polyP correlates with increased senescence in neuron-like SH-SY5Y cells. Short-term starvation (STS) restores some mitochondrial functions in polyP-depleted cells but not senescence. Increased levels of AMPK are observed with STS in polyP-depleted cells. Mitochondrial function and energy metabolism are affected by polyP levels. Male C57BL/6 mice show increased polyP levels and AMPK activation after intermittent fasting. Findings suggest targeting mitochondrial polyP metabolism could help combat neuronal senescence. CONCLUSION: Mitochondrial polyP depletion triggers neuronal senescence. Dietary restriction benefits mitochondrial function but doesn't fully revert increased senescence. AMPK activation may serve as a protective mechanism in polyP-depleted neurons. Mitochondrial health is crucial for neuronal longevity and function. Further research on polyP could uncover therapeutic targets against neurodegeneration. KEYWORDS: neurons, mitochondrial function, dietary restriction, neurodegeneration, senescence, inorganic polyphosphate, AMPK, aging, fasting, energy metabolism