Longitudinal Gene Expression Analysis in Human Brain identifies biological processes underlying neuropathology in Down Syndrome

Trisomy 21 (Ts21) or Down syndrome (DS) is the most common genetic cause of intellectual disability. To investigate the consequences of Ts21 on human brain development, we have systematically analyzed the transcriptome of dorsolateral prefrontal cortex (DFC) and cerebellar cortex (CBC) using exon array mapping in DS and matched euploid control brains spanning from prenatal development to adulthood. We identify hundreds of differentially expressed (DEX) genes in the DS brains, many of which exhibit temporal changes in expression over the lifespan. To gain insight into how these DEX genes may cause specific DS phenotypes, we identified functional modules of co-expressed genes using several different bioinformatics approaches, including WGCNA and gene ontology analysis. A module comprised of genes associated with myelination, including those dynamically expressed over the course of oligodendrocyte development, was amongst those with the great levels of differential gene expression. Using Ts65Dn mouse line, the most common rodent model of DS, w e observed significant and novel defects in oligodendrocyte maturation and myelin ultrastructure; establishing a correlative proof-of-principle implicating myelin dysgenesis in DS. Thus, examination of the spatio-temporal transcriptome predicts specific cellular and functional events in the DS brain and is an outstanding resource for determining putative mechanisms involved in the neuropathology of DS.

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Olmos-Serrano JL, Kang HJ, Tyler WA, Silbereis JC, Cheng F, Zhu Y, Pletikos M, Jankovic-Rapan L, Cramer NP, Galdzicki Z, Goodliffe J, Peters A, Sethares C, Delalle I, Golden JA, Haydar TF, Sestan N