Tau exacerbates excitotoxic brain damage in an animal model of stroke
Neuronal excitotoxicity induced by aberrant excitation of glutamatergic receptors contributes to brain damage in stroke. Here, we show that tau-deficient (tau-/-) mice are profoundly protected from excitotoxic brain damage and neurological deficits following experimental stroke, using a middle cerebral artery occlusion (MCAO) with reperfusion model. Mechanistically, we show that this protection is due to site-specific inhibition of glutamate-induced and Ras/ERK-mediated toxicity by accumulation of Ras-inhibiting SynGAP1, which resides in a post-synaptic complex with tau. Accordingly, reducing SynGAP1 levels in tau-/- mice abolished the protection from pharmacologically induced excitotoxicity and MCAO-induced brain damage. Conversely, over-expression of SynGAP1 prevented excitotoxic ERK activation in wild-type neurons. Our findings suggest that tau mediates excitotoxic Ras/ERK signaling by controlling post-synaptic compartmentalization of SynGAP1. Overall design: Total RNA was extracted from control and Tau -/- primary neurons from PTZ treated and untreated C57Bl/6 mice. Mice treated with PTZ were injected intraperitoneally at 6 weeks of age. The final libraries were paired end sequenced on Illumina HiSeq 2000.