Suppression of microRNA-9-5p rescues learning and memory in chronic cerebral hypoperfusion rats model

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Chronic cerebral hypoperfusion is a key factor in cognitive decline associated with Alzheimer's disease (AD) and vascular dementia (VaD).
• Effective treatments for AD and VaD remain elusive, highlighting the need for novel therapeutic targets.
• MicroRNAs (miRNAs) are crucial epigenetic regulators implicated in neurological disorders, with dysregulation observed in both AD and VaD.

Purpose of the Study:

• To investigate the role of miR-9-5p in chronic cerebral hypoperfusion-induced cognitive impairment.
• To evaluate the therapeutic potential of targeting miR-9-5p for memory deficits.

Main Methods:

• Quantified miR-9-5p levels in serum, cerebrospinal fluid, and brain tissue of patients and animal models with chronic cerebral hypoperfusion.
• Administered miR-9-5p antagomirs to rats subjected to 2-vessel occlusion surgery.
• Assessed memory function using behavioral tests (Morris water maze, inhibitory avoidance step-down).
• Evaluated synaptic plasticity (long-term potentiation), dendritic spine density, cholinergic function, neuronal loss, and oxidative stress.

Main Results:

• miR-9-5p was significantly elevated in patients and animal models with chronic cerebral hypoperfusion.
• Treatment with miR-9-5p antagomirs reversed memory impairments in behavioral tests.
• Antagomir treatment restored long-term potentiation, increased dendritic spine density, rescued cholinergic neuronal function, reduced neuronal loss, and mitigated oxidative stress.

Conclusions:

• miR-9-5p is a potential biomarker for chronic cerebral hypoperfusion.
• Inhibition of miR-9-5p demonstrates therapeutic efficacy in ameliorating memory deficits and associated neuropathology.
• Targeting miR-9-5p represents a promising therapeutic strategy for memory impairments resulting from chronic cerebral hypoperfusion.