ABSTRACT
INTRODUCTION: Presenilin-1 (PSEN1) gene mutations are the most common cause of familial Alzheimer's disease (fAD) and are known to interfere with activity of the membrane imbedded γ-secretase complex. PSEN1 mutations have been shown to shift Amyloid-ß precursor protein (AßPP) processing toward amyloid-ß (Aß) 1-42 production. However, less is known about whether PSEN1 mutations may alter the activity of enzymes such as ADAM10, involved with non-amyloidogenic AßPP processing, and markers of oxidative stress. MATERIALS AND METHODS: Control and PSEN1 mutation (L286V and R278I) Human Neural Stem Cells were spontaneously differentiated into neuron and astrocyte co-cultures. Cell lysates and culture media were collected and stored at -80 °C until further analysis. ADAM10 protein expression, the ratio of AßPP forms and Aß1-42/40 were assessed. In addition, cellular redox status was quantified. RESULTS: The ratio of AßPP isoforms (130:110kDa) was significantly reduced in neuron and astrocyte co-cultures carrying PSEN1 gene mutations compared to control, and mature ADAM10 expression was lower in these cells. sAßPP-α was also significantly reduced in L286V mutation, but not in the R278I mutation cells. Both Aß1-40 and Aß1-42 were increased in conditioned cell media from L286V cells, however, this was not matched in R278I cells. The Aß1-42:40 ratio was significantly elevated in R278I cells. Markers of protein carbonylation and lipid peroxidation were altered in both l286V and R278I mutations. Antioxidant status was significantly lower in R278I cells compared to control cells. CONCLUSIONS: This data provides evidence that the PSEN1 mutations L286V and R278I significantly alter protein expression associated with AßPP processing and cellular redox status. In addition, this study highlights the potential for iPSC-derived neuron and astrocyte co-cultures to be used as an early human model of fAD.
