title: RNA-Seq analysis of the parietal cortex in Alzheimer's disease reveals alternatively spliced isoforms related to lipid metabolism.
abstract: The parietal cortex of the human brain plays a unique role in the coordination of movement and in the integration of signals from the other cortices. Because of its extensive connections and involvement in many higher-order cognitive functions, neurodegenerative changes in the parietal lobe are believed to be crucial in the early symptoms of Alzheimer's disease (AD). Little is known about the transcriptome of this part of the human brain or how it is perturbed by the neurodegenerative process. To that end, we performed mRNA sequencing using the Illumina RNA-Seq technique on samples derived from normal and AD parietal lobes. Gene expression analysis evaluating alternatively spliced isoform expression and promoter usage revealed surprisingly elevated transcriptome activity in the AD condition. This phenomenon was particularly apparent in the alternative usage of transcriptional start sites. A Gene Ontology analysis of the differentially expressed genes revealed enrichment in the functional pathways related to lipid metabolism, thus highlighting the importance of astrocyte activity in the neurodegenerative process. We also identified an upregulation of the diazepam-binding inhibitor (DBI) gene in AD, as the result of a splicing switch toward shorter, intron-retaining isoforms driven by alternative promoters and was coupled with a simultaneous decrease in the abundance of protein-coding transcripts. These two DBI isoforms have not been described previously.
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: James D
authors.initials: JD
authors.lastname: Mills
authors.forename: Thomas
authors.initials: T
authors.lastname: Nalpathamkalam
authors.forename: Heidi I L
authors.initials: HI
authors.lastname: Jacobs
authors.forename: Caroline
authors.initials: C
authors.lastname: Janitz
authors.forename: Daniele
authors.initials: D
authors.lastname: Merico
authors.forename: Pingzhao
authors.initials: P
authors.lastname: Hu
authors.forename: Michael
authors.initials: M
authors.lastname: Janitz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017398:Alternative Splicing; D000544:Alzheimer Disease / Q000378:metabolism*; D026261:Diazepam Binding Inhibitor / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D010296:Parietal Lobe / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D017423:Sequence Analysis, RNA; D059467:Transcriptome
chemical_list: D026261:Diazepam Binding Inhibitor; D012333:RNA, Messenger