The 'mitochondrial guardian' α-amyrin links colourful fruit consumption to cognitive resilience.

Abstract

Mitochondrial quality control is essential for maintaining neuronal function and resilience during aging, yet pharmacological strategies that effectively restore mitophagy to maintain mitochondrial homeostasis remain limited. Emerging evidence suggests that dietary molecules may influence mitochondrial health, although the underlying mechanisms are largely unknown. Here, we summarize our recent finding whereby we have identified a robust mitophagy inducer: α-amyrin (αA). This molecule is a lipid-like pentacyclic triterpenoid abundant in edible plants, such as passion fruit. Mechanistically, αA targets dual leucine zipper kinase (DLK), a neuron-enriched stress kinase that plays a central role in axonal degeneration signaling. Under pathological stress, DLK activates the degeneration mediator SARM1, which can sequester the key autophagy/mitophagy protein ULK1 leading to compromised autophagy and mitophagy. By specifically binding to DLK, αA releases ULK1 from SARM1-mediated restriction and promotes ULK1-dependent mitophagy, restoring mitochondrial homeostasis. This mechanism reveals the DLK-SARM1-ULK1 cascade as a previously underappreciated regulatory interface linking neuronal stress signaling to mitochondrial surveillance pathways. More broadly, these findings introduce lipid-like dietary molecules as potential "mitochondrial guardians" that preserve organelle integrity through physiological activation of mitophagy. Targeting the DLK-SARM1-ULK1 axis with such molecules may represent a promising strategy for maintaining mitochondrial health and mitigating neurodegenerative processes associated with aging.