Doxycycline counteracts neuroinflammation restoring memory in Alzheimer's disease mouse models

beta-Amyloid oligomers (A beta Os) and neuroinflammation are 2 main culprits to counteract in Alzheimer's disease (AD). Doxycycline (DOXY) is a second generation antibiotic of the tetracycline class that are promising drugs tested in many clinical trials for a number of different pathologies. DOXY is endowed with antiamyloidogenic properties and better crosses the blood-brain barrier, but its efficacy has never been tested in AD mice. We herein show that 15- to 16-month-old APP/PS1dE9 (APP/PS1) AD mice receiving DOXY under different treatment regimens recovered their memory without plaque reduction. An acute DOXY treatment was, also, sufficient to improve APP/PS1 mouse memory, suggesting an action against soluble A beta Os. This was confirmed in an A beta O-induced mouse model, where the A beta O-mediated memory impairment was abolished by a DOXY pretreatment. Although A beta Os induce memory impairment through glial activation, assessing the anti-inflammatory action of DOXY, we found that in both the A beta O-treated and APP/PS1 mice, the memory recovery was associated with a lower neuroinflammation. Our data promote DOXY as a hopeful repositioned drug counteracting crucial neuropathological AD targets. (C) 2018 Elsevier Inc. All rights reserved.