GM1, in turn, is a ganglioside usually associated with neuroprotective effects. The exact mechanism involved in its neuroprotective action is not completely understood, however GM1 is able to enhance/potentiate neurotrophin release and action (Rabin et al., 2002 and Mocchetti, 2005), to exert antioxidant effects (Fighera et al., 2004, Furian et al., 2007 and Gavella et al., 2007), to prevent/revert glutamate induced excitotoxicity (Cunha et al., 1999), and to modulate some signaling pathways involved in death/survival processes (Mutoh et al., 1995, Pitto et al., 1998, Lili et al., 2005, Duchemin et
al., 2002 and Duchemin et al., 2008). On the other hand, several studies have attributed a participation in the mechanisms of Aβ aggregation to GM1 since the interaction of the peptide with this ganglioside could Selleckchem EPZ-6438 GW786034 act as a seed for the aggregation process, accelerating or even potentiating its fibrillation on membrane surfaces. This effect, however, seems to depend on a clustering of this ganglioside into membrane microdomains (lipid rafts) (Matsuzaki, 2007 and Yanagisawa, 2007), as well as on the pH and ionic concentration of the medium (McLaurin et al., 1998). Besides that, other studies have suggested a participation
of GM1 ganglioside in maturation of Amyloid Precursor Protein (APP), affecting its localization on membrane surface, and therefore, positively modulating Aβ production (Ehehalt et al., 2003, Zha et al., 2004 and Zhang et al., 2009). To further investigate the role of this ganglioside (neuroprotective DNA ligase or not) in the present model, we performed experiments consisting in the treatment of slices cultures with a saline GM1 solution,
in order to assess a possible effect of this ganglioside upon the Aβ25–35 induced toxicity. Considering that just fibrillar Aβ25–35 was able to trigger toxicity in our model, we have chosen this peptide form to perform the neuroprotective investigation. The pretreatment of slices with 10 μM GM1, 48 h previous to Aβ25–35 addition, was able to significantly prevent the amyloid toxicity measured after 48 h of amyloid incubation, as the PI uptake experiments have demonstrated (Fig. 3). Several studies have indicated the existence of a link among Aβ toxicity, progression of Alzheimer’s disease, and the activation of the GSK3β signaling pathway. This signaling pathway exerts an important effect on neurons, triggering the activation of cell death processes that could include oxidative stress induction and apoptosis response activation.