Bone Marrow-Derived GCA⁺ Immune Cells Drive Alzheimer's Disease Progression

Area of Science:

• Neuroscience
• Immunology
• Gerontology

Background:

• Alzheimer's disease (AD) is a CNS neurodegenerative disorder.
• The role of bone marrow immune cells in AD pathogenesis is not fully understood.

Purpose of the Study:

• To investigate the role of grancalcin (GCA) and GCA-expressing immune cells in Alzheimer's disease.
• To explore GCA as a potential therapeutic target for AD.

Main Methods:

• Measured GCA levels in AD patients and healthy individuals.
• Utilized AD mouse models, including cell transplantation and genetic ablation of GCA.
• Investigated the mechanism of GCA action on microglia and amyloid-beta (Aβ) clearance.
• Administered GCA-neutralizing antibodies in AD mouse models.

Main Results:

• AD patients exhibit higher circulating GCA levels, correlating with cognitive impairment.
• Bone marrow-derived GCA+ immune cells infiltrate the brain (hippocampus, cortex) in an AD mouse model via CCR10.
• GCA exacerbates amyloid plaque load and cognitive deficits; GCA ablation improves function.
• GCA inhibits microglial Aβ clearance by binding to LRP1.
• GCA-neutralizing antibodies improve cognitive function and reduce AD pathology.

Conclusions:

• GCA+ immune cells play a pathological role in AD, driving cognitive and memory decline.
• GCA is a key mediator of neuroinflammation and neurodegeneration in AD.
• Targeting GCA+ immune cells or GCA itself presents a promising therapeutic avenue for Alzheimer's disease.