Sanchez-Mirasierra, I. | Search bioRxiv

bioRxiv2026

The autophagy core protein Atg18 regulates exosome release and rescues pathogenic dysfunction associated to Parkinson Sac domain mutation in Synaptojanin

Macroautophagy, a catabolic process conserved across evolution, participates in fundamental aspects of synaptic function and neuronal survival. Exosomes are extracellular vesicles that mediate cell communication, including emerging roles mediating brain intercellular signaling, synaptic function and neuronal survival. Indeed, both autophagy and exosome release interact with each other, but this interplay is poorly characterized at the neuronal synapse, especially in the context of neurodegenerative diseases. Here, we report that at the presynaptic compartment the autophagy protein Atg18a/WIPI2 regulates exosome release at the level of the multivesicular body. The Parkinson disease mutation R258Q in the protein Synaptojanin inhibits synaptic autophagy, and causes locomotion deficits, seizures and neurodegeneration. We found that this mutation also reduces exosome release and that the dopaminergic overexpression of Atg18a in Synaptojanin mutant animals restores exosome release, locomotion and dopaminergic survival without restoring synaptic autophagy. Our data reports a novel function of Atg18a in the regulation of exosome release and spotlights the role of exosome release in the pathogenesis of Parkinson disease.

neuroscience↗

bioRxiv2023

Synaptogyrin regulates neuronal activity dependent autophagy to degrade synaptic vesicle components and pathological Tau

Synapses are specialized neuronal compartments essential for brain communication. Neuronal communication mostly relies on the adequate supply and renovation of synaptic vesicles that fuse with the plasma membrane and release neurotransmitters in response to action potentials. Autophagy is an evolutionary conserved cellular mechanism essential for homeostasis that can be locally regulated in the neuronal synapse. However, the precise mechanisms controlling synaptic autophagy, especially during neuronal communication and pathological scenarios, remain elusive. Here, we report that neuronal activity and amino-acid deprivation regulate synaptic autophagy via distinct molecular mechanisms. We show that Synaptogyrin, a highly abundant presynaptic protein found in synaptic vesicles, is a novel negative regulator of synaptic autophagy in response to neuronal activity without affecting autophagy induction via amino-acid deprivation. We demonstrate that loss of Synaptogyrin modifies the localization of the autophagy protein Atg9 and boosts autophagosome formation at the synapse. Furthermore, activation of synaptic autophagy by loss of Synaptogyrin, but not by amino-acid deprivation, leads to the degradation of synaptic vesicle components via autophagy. Reducing the levels of Synaptogyrin results in the degradation of synaptic Tau via autophagy and restores autophagy dysfunction observed in a Drosophila Tau model of Frontotemporal Dementia (FTD). Our data provide novel and valuable information to understand how autophagy is regulated at the synapse in response to neuronal activity and how this process participates in neuronal (dys)function.

neuroscience↗