Down regulation of PTEN is neuroprotective in acute experimental models. (A) and (B) Downregulation of PTEN with specific siRNA confers neuroprotection 24 h after Aβ exposure (25 μM): PTEN IHC staining (red, A) and MAP/NeuN staining for neuron morphology (green, B). (C) Reduced PTEN protein level in PTEN heterozygous mouse brain (frontal region), accompanied by elevated P-Akt level (2-month-old mice, n = 2). (D) Primary cultured cortical neurons from PTEN +/- pups manifest less apoptotic cell death than PTEN+/+ neurons 24 h after Aβ exposure. Data presented as means ± SD from 5 independent experiments.