Secretory autophagy - a new paradigm regulating synaptic plasticity.

Area of Science:

• Neuroscience
• Cell Biology
• Molecular Biology

Background:

• Neurons rapidly change structure and function in response to activity, a process called activity-induced synaptic remodeling.
• This remodeling is vital for memory formation, but the underlying molecular mechanisms are not fully understood.
• Synaptic plasticity and neurodevelopment share regulatory processes, complicating the study of acute synaptic changes.

Purpose of the Study:

• To investigate the molecular mechanisms of activity-induced synaptic remodeling.
• To determine the role of autophagy in synaptic plasticity and memory formation.
• To identify novel pathways involved in trans-synaptic signaling.

Main Methods:

• Conducted an RNA interference (RNAi) screen in *Drosophila* targeting genes related to human nervous system function.
• Investigated the role of macroautophagy and its components in synaptic plasticity.
• Manipulated secretory autophagy pathway genes (Sec22, Snap29, Rab8) and monitored autophagy activity.

Main Results:

• Macroautophagy is essential for synapse development and plasticity, but activity-induced remodeling does not depend on lysosomal degradation genes.
• Knocking down secretory autophagy components (Sec22, Snap29, Rab8) disrupted structural and functional synaptic plasticity.
• Neuronal activity suppressed degradative autophagy, promoting a shift towards secretory autophagy release.

Conclusions:

• Secretory autophagy, an unconventional pathway, is crucial for activity-induced synaptic remodeling.
• Autophagosomes fuse with the plasma membrane to release contents extracellularly, acting as a novel trans-synaptic signaling mechanism.
• This pathway is critical for transforming experiences into stable memories.