Leptin gene therapy attenuates neuronal damages evoked by amyloid-β and rescues memory deficits in APP/PS1 mice

There is growing evidence that leptin is able to ameliorate Alzheimer's disease (AD)-like pathologies, including brain amyloid-beta (A beta) burden. In order to improve the therapeutic potential for AD, we generated a lentivirus vector expressing leptin protein in a self-inactivating HIV-1 vector (HIV-leptin), and delivered this by intra-cerebroventricular administration to APP/PS1 transgenic model of AD. Three months after intra-cerebroventricular administration of HIV-leptin, brain A beta accumulation was reduced. By electron microscopy, we found that APP/PS1 mice exhibited deficits in synaptic density, which were partially rescued by HIV-leptin treatment. Synaptic deficits in APP/PS1 mice correlated with an enhancement of caspase-3 expression, and a reduction in synaptophysin levels in synaptosome preparations. Notably, HIV-leptin therapy reverted these dysfunctions. Moreover, leptin modulated neurite outgrowth in primary neuronal cultures, and rescued them from A beta(42)-induced toxicity. All the above changes suggest that leptin may affect multiple aspects of the synaptic status, and correlate with behavioral improvements. Our data suggest that leptin gene delivery has a therapeutic potential for A beta-targeted treatment of mouse model of AD.