CCR5 regulates Aβ_1-42-induced learning and memory deficits in mice

Area of Science:

• Neuroscience
• Immunology
• Pharmacology

Background:

• C-C chemokine receptor 5 (CCR5) is crucial for immune responses and HIV entry.
• CCR5 influences synaptic plasticity and cognitive functions, with roles in aging, TBI, and HAND.
• CCR5's specific role in Alzheimer's disease (AD) cognitive deficits remains unclear, despite observed increases in CCR5 expression in AD models.

Purpose of the Study:

• To investigate the causal role of CCR5 in Aβ_1-42-induced cognitive deficits in AD.
• To determine if blocking CCR5 in the hippocampus can ameliorate memory impairments in AD mouse models.

Main Methods:

• Administered soluble Aβ_1-42 oligomers into the dorsal CA1 hippocampus of mice.
• Assessed memory function using object place recognition (OPR) and novel object recognition (NOR) tests.
• Quantified Ccr5, Ccl3, and Ccl4 expression and measured microglia changes after Ccr5 knockdown.

Main Results:

• Aβ_1-42 injection induced significant memory deficits and increased Ccr5, Ccl3, and Ccl4 expression in the hippocampus.
• Elevated CCR5 and ligand levels persisted for at least two weeks post-injection.
• Knocking down Ccr5 in the CA1 region reversed Aβ_1-42-induced microgliosis and rescued memory impairments.

Conclusions:

• CCR5 plays a critical role in mediating learning and memory deficits induced by Aβ_1-42.
• Targeting CCR5 with antagonists presents a potential therapeutic strategy for improving cognitive function in Alzheimer's disease.