Abl depletion via autophagy mediates the beneficial effects of quercetin against Alzheimer pathology across species
Alzheimer's disease is the most common age-associated neurodegenerative disorder and the most frequent form of dementia in our society. Aging is a complex biological process concurrently shaped by genetic, dietary and environmental factors and natural compounds are emerging for their beneficial effects against age-related disorders such as cancer or cardiovascular diseases. Besides their antioxidant activity often described in simple model organisms, the molecular mechanisms underlying the beneficial effects of different dietary compounds remain largely unknown. Here, we exploited widely established C. elegans models for AD to test the effects of different natural compounds in vivo and focused on mechanistic aspects of one of them, quercetin, using complementary systems and assays. We show that quercetin has evolutionarily conserved beneficial effects against AD pathology: it prevents Aß-induced detrimental effects in different C. elegans AD models and it reduces Aß-secretion in mammalian cells. Mechanistically, we found that the beneficial effects of quercetin are mediated by autophagy-dependent reduced expression of Abl tyrosine kinase. In turn, autophagy is required upon Abl suppression to mediate quercetin's protective effects against Aß toxicity. Our data support the power of C. elegans as an in vivo model to investigate therapeutic options for Alzheimer disease. Overall design: Worms were collected on day 3 after  birth, with 5 independent replicates performed for both control and  quercetin treated groups, while 4 independent replicates were performed for  lutein.