Extracellular Vesicles-Dependent Secretion Regulates Intracellular CYFIP2 Protein Homeostasis in Cortical Neurons.

Area of Science:

• Neuroscience
• Cell Biology
• Genetics

Background:

• Fragile X Syndrome (FXS) is a leading genetic cause of autism spectrum disorders.
• FXS is linked to synaptic pathology, including excitatory/inhibitory imbalance and altered synaptic protein levels.
• CYFIP2, a key synaptic regulator, is dysregulated in FXS, but the underlying mechanism is unclear.

Purpose of the Study:

• To investigate the role of extracellular vesicle (EV)-dependent secretion in regulating intracellular CYFIP2 protein levels.
• To determine if EV secretion mechanisms are altered in Fragile X Syndrome (FXS) neurons.

Main Methods:

• Proteomic analysis to identify CYFIP2 in neuronal EVs.
• Pharmacological and genetic inhibition of EV release in mouse cortical neurons.
• Assessment of EV secretion and CYFIP2 levels in wild-type (WT) and Fmr1 knockout (FXS model) neurons.

Main Results:

• CYFIP2 protein is packaged and secreted via EVs from mouse cortical neurons.
• Inhibition of EV release significantly increased intracellular CYFIP2 levels.
• FXS model neurons exhibited reduced EV secretion and elevated intracellular CYFIP2.
• Stimulating EV release reduced CYFIP2 levels in both WT and FXS neurons.

Conclusions:

• An EV-secretion-dependent mechanism controls neuronal CYFIP2 levels.
• EV-mediated export is implicated in maintaining synaptic protein homeostasis.
• Dysregulated EV secretion may contribute to synaptic deficits observed in Fragile X Syndrome.