PDE4A and Alzheimer disease: Studies have demonstrated that ameliorating neuroinflammation mediated by microglia can attenuate the pathology of AD.50 This is consistent with our previous studies showing that the pan-PDE4 inhibitor rolipram attenuates neuroinflammation, reduces microglial activation, decreases Aβ accumulation, and enhances cognitive function in AD mice.40 The present study further demonstrated that selective inhibition of PDE4B by A33 ameliorated cognitive impairment in AlD mice.