BackgroundEpigenome-wide association studies (EWAS) based on human brain samples allow a deep and direct understanding of epigenetic dysregulation in Alzheimer’s disease (AD). However, strong variation of cell-type proportions across brain tissue samples represents a significant source of data noise. Here, we report the first EWAS based on sorted neuronal and non-neuronal (mostly glia) nuclei from postmortem human brain tissues.ResultsWe show that cell sorting strongly enhances the robust detection of disease-related DNA methylation changes even in a relatively small cohort. We identify numerous genes with cell-type-specific methylation signatures and document differential methylation dynamics associated with aging specifically in neurons such as CLU, SYNJ2 and NCOR2 or in glia RAI1,CXXC5 and INPP5A. Further, we found neuron or glia-specific associations with AD Braak stage progression at genes such as MCF2L, ANK1, MAP2, LRRC8B, STK32C and S100B. A comparison of our study with previous tissue-based EWAS validates multiple AD-associated DNA methylation signals and additionally specifies their origin to neuron, e.g., HOXA3 or glia (ANK1). In a meta-analysis, we reveal two novel previously unrecognized methylation changes at the key AD risk genes APP and ADAM17.ConclusionsOur data highlight the complex interplay between disease, age and cell-type-specific methylation changes in AD risk genes thus offering new perspectives for the validation and interpretation of large EWAS results.Electronic supplementary materialThe online version of this article (10.1186/s13072-018-0211-3) contains supplementary material, which is available to authorized users.

Parkinson's disease (PD) is a slowly progressing neurodegenerative disorder that affects approximately seven million patients worldwide. Despite intensive research, the molecular mechanisms initiating and promoting PD are still unknown. However, it is assumed that environmental factors trigger PD. Recent research demonstrated that long noncoding RNAs (lncRNA) interfere in transcriptional and translational processes modulating gene expression reflecting environmental influences. Nevertheless, there is no systematic analysis available that investigates the impact of lncRNAs on PD. In the current study, we performed a comprehensive analysis on expression levels of 90 well-annotated lncRNAs in 30 brain specimens deriving from 20 PD patients and 10 controls as a preliminary report on the significance of lncRNAs in PD. Expression profiling of lncRNAs revealed that five lncRNAs are significantly differentially expressed in PD. While H19 upstream conserved 1 and 2 is significantly downregulated in PD, lincRNA-p21, Malat1, SNHG1, and TncRNA are significantly upregulated. An analysis on expression levels and PD stages revealed that the identified dysregulated lncRNA are altered already in early disease stage and that they precede the course of PD. In summary, this is the first comprehensive analysis on lncRNAs in PD revealing significantly altered lncRNAs. Additionally, we found that lncRNA dysregulations precede the course of the disease. Thus, the five newly identified lncRNAs may serve as potential new biomarkers appropriate even in early PD. They may be used in monitoring disease progression and they may serve as potential new targets for novel therapeutic approaches.

Background: Wnt signaling drives epithelial self-renewal and disease progression in human colonic epithelium and colorectal cancer (CRC). Characterization of Wnt effector pathways is key for our understanding of these processes and for developing therapeutic strategies that aim to preserve tissue homeostasis. O-glycosylated cell surface proteins, such as α-dystroglycan (α-DG), mediate cellular adhesion to extracellular matrix components. We revealed a Wnt/LARGE2/α-DG signaling pathway which triggers this mode of colonic epithelial cell-to-matrix interaction in health and disease. Methods: Next generation sequencing upon shRNA-mediated silencing of adenomatous polyposis coli (APC), and quantitative chromatin immunoprecipitation (qChIP) combined with CRISPR/Cas9-mediated transcription factor binding site targeting characterized LARGE2 as a Wnt target gene. Quantitative mass spectrometry analysis on sizefractionated, glycoprotein-enriched samples revealed functional O-glycosylation of α-DG by LARGE2 in CRC. The biology of Wnt/LARGE2/α-DG signaling was assessed by affinity-based glycoprotein enrichment, laminin overlay, CRC-to-endothelial cell adhesion, and transwell migration assays. Experiments on primary tissue, human colonic (tumor) organoids, and bioinformatic analysis of CRC cohort data confirmed the biological relevance of our findings.