Abstract
INTRODUCTION The purinergic receptor P2X7R, which is expressed on microglia and astrocytes, plays an important role in Alzheimer’s disease (AD). We aimed to characterize the alterations in P2X7R expression in AD patients by APOE ε4 allele, age and sex, as well as its association with amyloid and tau pathology.
METHODS P2X7R staining and quantitative analysis of amyloid, tau, astrocytes and microglia were performed on postmortem hippocampal tissues from 35 AD patients; 31 nondemented controls; caudate/putamen tissue from corticobasal degeneration (CBD), progressive supranuclear palsy (PSP) patients; and bran tissue from aged 3×Tg mouse model of AD.
RESULTS Activated microglia and reactive astrocytes were observed in the hippocampi of AD patients and exhibited altered morphology with denser cells and pronounced ramifications. Hippocampal P2X7R intensity was greater in the hippocampal subfields of AD patients than in those of nondemented controls and was correlated with amyloid level and Braak stage and was not affected by sex, APOEε4 allele, or age. P2X7R expression increased around Aβ plaques, cerebral amyloid angiopathy, tau inclusions in the hippocampus from AD patients and tau inclusions in the caudate/putamen from CBD and PSP patients.
DISCUSSION We found an increased hippocampal P2X7R level in AD compared to non-demented control, which correlated with amyloid and tau pathologies. P2X7R is a potential marker for neuroinflammation in AD.
Competing Interest Statement
CH and RMN are employees and shareholders of Neurimmune AG. Other authors declare no conflicts of interest.
