Induction of autophagy by spermidine promotes longevity

TLDR: Administration of spermidine markedly extended the lifespan of yeast, flies and worms, and human immune cells and inhibited oxidative stress in ageing mice, and found that enhanced autophagy is crucial for polyamine-induced suppression of necrosis and enhanced longevity.

Abstract: Ageing results from complex genetically and epigenetically programmed processes that are elicited in part by noxious or stressful events that cause programmed cell death Here, we report that administration of spermidine, a natural polyamine whose intracellular concentration declines during human ageing, markedly extended the lifespan of yeast, flies and worms, and human immune cells In addition, spermidine administration potently inhibited oxidative stress in ageing mice In ageing yeast, spermidine treatment triggered epigenetic deacetylation of histone H3 through inhibition of histone acetyltransferases (HAT), suppressing oxidative stress and necrosis Conversely, depletion of endogenous polyamines led to hyperacetylation, generation of reactive oxygen species, early necrotic death and decreased lifespan The altered acetylation status of the chromatin led to significant upregulation of various autophagy-related transcripts, triggering autophagy in yeast, flies, worms and human cells Finally, we found that enhanced autophagy is crucial for polyamine-induced suppression of necrosis and enhanced longevity