Neural stem cell-derived exosomes improve neurite outgrowth and cognitive function through transferring miR-132-3p

Area of Science:

• Neuroscience
• Cell Biology
• Biochemistry

Background:

• Vascular dementia (VD) is characterized by significant neuronal damage and synaptic impairment.
• Exosomes derived from neural stem cells (NSCs) show neuroprotective potential, with exosomal microRNAs (miRs) playing a key role.
• miR-132-3p is identified as a crucial proneurogenic microRNA involved in neuronal health.

Purpose of the Study:

• To investigate the therapeutic role of miR-132-3p-enriched NSC-exosomes (NSC-EXs) in mitigating neuronal damage and synaptic deficits in VD.
• To elucidate the underlying molecular mechanisms by which miR-132-3p exerts its neuroprotective effects in the context of VD.

Main Methods:

• Preparation of NSC-EXs, NSC-EXs enriched with miR-132-3p (NSC-EXs^miR-132-3p), and NSC-EXs deficient in miR-132-3p (NSC-EXs^simiR-132-3p).
• Co-culture of these exosomes with oxygen- and glucose-deprived (OGD)-injured neurons and administration to VD mouse models.
• Bioinformatic analyses and luciferase assays to identify miR-132-3p target genes.

Main Results:

• Levels of NSC-EXs and miR-132-3p were reduced in the hippocampi of VD mice.
• NSC-EXs^miR-132-3p significantly improved cognitive function, increased neuron number and dendritic spine density, and reduced neuronal apoptosis and ROS production in VD mice.
• In vitro, NSC-EXs^miR-132-3p promoted neurite outgrowth and reduced oxidative stress and apoptosis in OGD-injured neurons.
• miR-132-3p targets RASA1, leading to increased Ras expression and ERK1/2 phosphorylation.

Conclusions:

• Enrichment of NSC-EXs with miR-132-3p enhances their therapeutic efficacy for VD-induced neuronal and synaptic damage.
• The mechanism involves the inhibition of RASA1 and subsequent activation of the Ras/ERK1/2 signaling pathway.
• miR-132-3p-modified NSC-EXs represent a promising therapeutic strategy for vascular dementia.