The potential role of presenilin 1 in regulation of synaptic function

One of the earliest neuropathological symptoms of Alzheimer's disease is the loss of synapses that precedes the formation of amyloid plaques and neurodegeneration. Although most cases of early-onset familial Alzheimer's disease are caused by mutations in the presenilin 1 (PS1) gene, the functions of PS1 and its role in synaptic dysfunction are not yet completely understood. In this paper, we analyzed PS1 intra- and extracellular distribution in cultures of mouse cortical embryonic neurons. We found that PS1 was concentrated on the surface of the growth cone and neurite contact sites. PS1 was also found in synapses where it was colocalized with synaptophysin. We obtained independent evidence of PS1 involvement in synaptic function by transfection of neurons with GFP-PS1cDNA. GFP was colocalized with synaptophysin in transfected cultures. GFP-immunoprecepitates from transfected neurons contained N-cadherin. This finding represents additional evidence of PS1 participation in the synapse formation. To evaluate the role of PS1 inactivation in the synaptic functions, we compare the synaptic density in neuronal cell cultures from knockout mice PS1 (-/-) and wild type mice PS1 (+/+). Our results obviously show that PS1 (-/-) cultures displayed lower number of morphological synapses compared to wild type culture PS1 (+/+). In summary, our findings show the role of PS1 in synaptic function. © 2012 Pleiades Publishing, Ltd.

Duke Scholars

Author Michael P. Vitek Neurology, Behavioral Neurology