RT Journal Article
SR Electronic
T1 Dedifferentiation and neuronal repression define Familial Alzheimer’s Disease
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 531202
DO 10.1101/531202
A1 Caldwell, Andrew B.
A1 Liu, Qing
A1 Schroth, Gary P.
A1 Galasko, Douglas R.
A1 Yuan, Shauna H.
A1 Wagner, Steven L.
A1 Subramaniam, Shankar
YR 2019
UL http://biorxiv.org/content/early/2019/11/18/531202.abstract
AB Early-Onset Familial Alzheimer’s Disease (EOFAD) is a dominantly inherited neurodegenerative disorder elicited by over 300 mutations in the PSEN1, PSEN2, and APP genes1. Hallmark pathological changes and symptoms observed, namely the accumulation of misfolded Amyloid-β (Aβ) in plaques and Tau aggregates in neurofibrillary tangles associated with memory loss and cognitive decline, are understood to be temporally accelerated manifestations of the more common sporadic Late-Onset Alzheimer’s Disease. The complete penetrance of EOFAD-causing mutations has allowed for experimental models which have proven integral to the overall understanding of AD2. However, the failure of pathology-targeting therapeutic development suggests that the formation of plaques and tangles may be symptomatic and not describe the etiology of the disease3,4. In this work, we used an integrative, multi-omics approach and systems-level analysis in hiPSC-derived neurons to generate a mechanistic disease model for EOFAD. Using patient-specific cells from donors harboring mutations in PSEN1 differentiated into neurons, we characterized the disease-related gene expression and chromatin accessibility changes by RNA-Seq, ATAC-Seq, and histone methylation ChIP-Seq. Here, we show that the defining disease-causing mechanism of EOFAD is dedifferentiation, causing neurons to traverse the lineage-defining chromatin landscape along an alternative axis to a mixed-lineage cell state with gene signature profiles indicative of less-defined ectoderm as well as non-ectoderm lineages via REST-mediated repression of neuronal lineage specification gene programs and the activation of non-specific germ layer precursor gene programs concomitant with modifications in chromatin accessibility. Further, a reanalysis of existing transcriptomic data from PSEN1 patient brain samples demonstrates that the mechanisms identified in our experimental system recapitulate EOFAD in the human brain. Our results comprise a disease model which describes the mechanisms culminating in dedifferentiation that contribute to neurodegeneration.