Assessment of the neurotoxic properties of Wnt3a treated microglia. Primary microglia (300000 cells per treatment) were treated with Wnt3a (10 nM), LPS (10 ng/ml), oligomeric Aβ (3 μM) or oligomeric α-synuclein (500 nM) for 24 hours and the medium was collected. Control medium was collected from untreated microglia in SFM (SFM). This medium was then added to cortical neuron cultures (500000 cells per treatment) for a further 24 hours before neurotoxicity assays were performed. Some neuronal cultures were exposed to conditioned medium collected from microglia treated with LPS (10 ng/ml), oligomeric Aβ (3 μM) or oligomeric α-synuclein (500 nM) in the presence of medium collected from Wnt3a treated microglia (as indicated). Neuronal death was assessed by MTT (grey bars) and LDH (black bars) assays. In addition, LPS (10 ng/ml), oligomeric Aβ (3 μM) or oligomeric α-synuclein (500 nM) were directly added to neuronal cultures in the presence of conditioned medium collected from control microglia to account for any direct neurotoxic effects of the microglial activators and toxicity was assessed by LDH assay (white bars: LDH control). * p < 0.05, ** p < 0.01.