Beneficial Effect of a Selective Adenosine A2A Receptor Antagonist in the APPswe/PS1dE9 Mouse Model of Alzheimer's Disease

Consumption of caffeine, a non-selective adenosine A(2A) receptor (A(2A)R) antagonist, reduces the risk of developing Alzheimer's disease (AD) and mitigates both amyloid and Tau lesions in transgenic mouse models of the disease. While short-term treatment with A(2A)R antagonists have been shown to alleviate cognitive deficits in mouse models of amyloidogenesis, impact of a chronic and long-term treatment on the development of amyloid burden, associated neuroinflammation and memory deficits has never been assessed. In the present study, we have evaluated the effect of a 6-month treatment of APPsw/PS1dE9 mice with the potent and selective A(2A)R antagonist MSX-3 from 3 to 9-10 months of age. At completion of the treatment, we found that the MSX-3 treatment prevented the development of memory deficits in APP/PS1dE9 mice, without significantly altering hippocampal and cortical gene expressions. Interestingly, MSX-3 treatment led to a significant decrease of A beta 1-42 levels in the cortex of APP/PS1dE9 animals, while A beta 1-40 increased, thereby strongly affecting the A beta 1-42/A beta 1-40 ratio. Together, these data support the idea that A(2A)R blockade is of therapeutic value for AD.