DNA methylation analysis on purified neurons and glia dissects age and Alzheimer's disease-specific changes in the human cortex
EPIGENETICS & CHROMATIN
Authors: Gasparoni, Gilles; Bultmann, Sebastian; Lutsik, Pavlo; Kraus, Theo F. J.; Sordon, Sabrina; Vlcek, Julia; Dietinger, Vanessa; Steinmaurer, Martina; Haider, Melanie; Mulholland, Christopher B.; Arzberger, Thomas; Roeber, Sigrun; Riemenschneider, Matthias; Kretzschmar, Hans A.; Giese, Armin; Leonhardt, Heinrich; Walter, Joern
Abstract
Background: Epigenome-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. Results: We 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 eell-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. Conclusions: Our 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.
Exposure to acoustic stimuli promotes the development and differentiation of neural stem cells from the cochlear nuclei through the clusterin pathway
INTERNATIONAL JOURNAL OF MOLECULAR MEDICINE
Authors: Xue, Tao; Wei, Li; Zha, Ding-Jun; Qiao, Li; Lu, Lian-Jun; Chen, Fu-Quan; Qiu, Jian-Hua
Abstract
Stem cell therapy has attracted widespread attention for a number of diseases. Recently, neural stem cells (NSCs) from the cochlear nuclei have been identified, indicating a potential direction for the treatment of sensorineural hearing loss. Acoustic stimuli play an important role in the development of the auditory system. In this study, we aimed to determine whether acoustic stimuli induce NSC development and differentiation through the upregulation of clusterin (CLU) in NSCs isolated from the cochlear nuclei. To further clarify the underlying mechanisms involved in the development and differentiation of NSCs exposed to acoustic stimuli, we successfully constructed animal models in which was CLU silenced by an intraperitoneal injection of shRNA targeting CLI. As expected, the NSCs from rats treated with LV-CLU shRNA exhibited a lower proliferation ratio when exposed to an augmented acoustic environment (AAE). Furthermore, the inhibition of cell apoptosis induced by exposure to AAE was abrogated after silencing the expression of the CLU gene. During the differentiation of acoustic stimuli-exposed stem cells into neurons, the number of astrocytes was significantly reduced, as evidenced by the expression of the cell markers, microtubule associated protein-2 (MAP-2) and glial fibrillary acidic protein (GFAP), which was markedly inhibited when the CLU gene was silenced. Our results indicate that acoustic stimuli may induce the development and differentiation of NSCs from the cochlear nucleus mainly through the CLU pathway. Our study suggests that CLU may be a novel target for the treatment of sensorineural hearing loss.