Amyloid-β precursor protein processing and oxidative stress are altered in human iPSC-derived neuron and astrocyte co-cultures carrying presenillin-1 gene mutations following spontaneous differentiation

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 gamma-secretase complex. PSEN1 mutations have been shown to shift Amyloid-beta precursor protein (A beta PP) processing toward amyloid-beta (A beta) 1-42 production. However, less is known about whether PSEN1 mutations may alter the activity of enzymes such as ADAM10, involved with non-amyloidogenic A beta PP 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 degrees C until further analysis. ADAM10 protein expression, the ratio of A beta PP forms and A beta 1-42/40 were assessed. In addition, cellular redox status was quantified. Results: The ratio of A beta PP 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. sA beta PP-alpha was also significantly reduced in L286V mutation, but not in the R278I mutation cells. Both A beta 1-40 and A beta 1-42 were increased in conditioned cell media from L286V cells, however, this was not matched in R278I cells. The A beta 1-42:40 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 A beta PP 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.

Automated summary

The study reveals the impact of PSEN1 gene mutations on AβPP processing and cellular redox status, demonstrating the potential of iPSC-derived neuron and astrocyte co-cultures as an early human model of fAD.