The dsRNA-enriched neural transcriptome drives neuroinflammation [neurons]
Ontology highlight
ABSTRACT: To confirm 3'UTR lengthening in neurons, we differentiated neurons from HEUS8, a human stem cell line and performed RNA sequenicng. HEK293T cells were used as a control
Project description:To investigate the effects of HuB, HuC, and HuD, which are neuron-specific RNA binding proteins in mRNA lengthening and innate immune responses, we transfected them in HEK293T cells and performed the RNA sequencing experiment.
Project description:Deposition of tau protein aggregates in the brain of affected individuals is a defining feature of "tauopathies," including Alzheimer's disease. Studies of human brain tissue and various model systems of tauopathy report that toxic forms of tau negatively affect nuclear and genomic architecture, identifying pathogenic tau-induced heterochromatin decondensation and consequent retrotransposon activation as a causal mediator of neurodegeneration. On the basis of their similarity to retroviruses, retrotransposons drive neuroinflammation via toxic intermediates, including double-stranded RNA (dsRNA). We find that dsRNA and dsRNA sensing machinery are elevated in astrocytes of postmortem brain tissue from patients with Alzheimer's disease and progressive supranuclear palsy and in brains of tau transgenic mice. Using a Drosophila model of tauopathy, we identify specific tau-induced retrotransposons that form dsRNA and find that pathogenic tau and heterochromatin decondensation causally drive dsRNA-mediated neurodegeneration and neuroinflammation. Our study suggests that pathogenic tau-induced heterochromatin decondensation and retrotransposon activation cause elevation of inflammatory, transposable element-derived dsRNA in the adult brain.
Project description:The 3' untranslated regions (3' UTRs) of mRNAs contain cis-acting elements for posttranscriptional regulation of gene expression. Here, we report that mouse genes tend to express mRNAs with longer 3' UTRs as embryonic development progresses. This global regulation is controlled by alternative polyadenylation and coordinates with initiation of organogenesis and aspects of embryonic development, including morphogenesis, differentiation, and proliferation. Using myogenesis of C2C12 myoblast cells as a model, we recapitulated this process in vitro and found that 3' UTR lengthening is likely caused by weakening of mRNA polyadenylation activity. Because alternative 3' UTR sequences are typically longer and have higher AU content than constitutive ones, our results suggest that lengthening of 3' UTR can significantly augment posttranscriptional control of gene expression during embryonic development, such as microRNA-mediated regulation. Two biological replicates of C2C12 growth and differentiation conditions, repesctively
Project description:Alternative polyadenylation is a widespread mechanism involving about half of the expressed genes, resulting in varying lengths of the 3' UTR and changes of the post-transcriptional processing, localization, miRNA targeting and stability of mRNAs. During neuronal differentiation a variety of mRNAs change the length of their 3' UTR, promoting the longer version of the transcripts. Little is known about polyA+ site usage during differentiation of mammalian neural progenitors. Here we exploit a model of adherent neural stem (ANS) cells, which homogeneously and efficiently differentiate into GABAergic neurons. RNAseq data shows a global trend towards lengthening of the 3’ UTRs during differentiation. Enriched expression of the long 3’ UTR variants of Pes1 and Gng2 was detected in areas of cortical and subcortical neuronal differentiation, respectively, in the mouse brain by two-probes FISH analyses. In Drosophila the choice of polyA+ site has been shown to be regulated by the RNA-binding protein Elav, which inhibits polyadenylation at proximal sites while interacting with paused Pol-II promoters. Among the coding genes upregulated during differentiation of ANS cells we found Elavl3, a neural-specific RNA-binding protein homologous to Drosophila Elav. The silencing of Elavl3 in ANS cells resulted in impaired elongation of the 3’UTR length and delayed neuronal differentiation. These results indicate that choice of the polyA+ site and lengthening of 3’ UTRs is a possible additional mechanism of posttranscriptional RNA modification involved in neuronal differentiation.
Project description:The 3' untranslated regions (3' UTRs) of mRNAs contain cis-acting elements for posttranscriptional regulation of gene expression. Here, we report that mouse genes tend to express mRNAs with longer 3' UTRs as embryonic development progresses. This global regulation is controlled by alternative polyadenylation and coordinates with initiation of organogenesis and aspects of embryonic development, including morphogenesis, differentiation, and proliferation. Using myogenesis of C2C12 myoblast cells as a model, we recapitulated this process in vitro and found that 3' UTR lengthening is likely caused by weakening of mRNA polyadenylation activity. Because alternative 3' UTR sequences are typically longer and have higher AU content than constitutive ones, our results suggest that lengthening of 3' UTR can significantly augment posttranscriptional control of gene expression during embryonic development, such as microRNA-mediated regulation.
Project description:Frontotemporal dementia (FTD) is an incurable group of early-onset dementias that can be caused by deposition of hyperphosphorylated tau in patient brains. However, the mechanisms leading to neurodegeneration remain largely unknown. Here, we combined single-cell analyses of FTD patient brains with a stem cell culture and transplantation model of FTD. We identified disease phenotypes in FTD neurons carrying the MAPT-N279K mutation, which were related to oxidative stress, oxidative phosphorylation and neuroinflammation with an upregulation of the inflammation-associated protein osteopontin (OPN). Human FTD neurons survived less and elicited an increased microglial response after transplantation into the mouse forebrain, that we further characterized by single nucleus RNA-sequencing of microdissected grafts. Notably, downregulation of OPN in engrafted FTD neurons resulted in improved engraftment and reduced microglial infiltration, indicating an immune-modulatory role of OPN in patient neurons, which may represent a potential therapeutic target in FTD.
Project description:Frontotemporal dementia (FTD) is an incurable group of early-onset dementias that can be caused by deposition of hyperphosphorylated tau in patient brains. However, the mechanisms leading to neurodegeneration remain largely unknown. Here, we combined single-cell analyses of FTD patient brains with a stem cell culture and transplantation model of FTD. We identified disease phenotypes in FTD neurons carrying the MAPT-N279K mutation, which were related to oxidative stress, oxidative phosphorylation and neuroinflammation with an upregulation of the inflammation-associated protein osteopontin (OPN). Human FTD neurons survived less and elicited an increased microglial response after transplantation into the mouse forebrain, that we further characterized by single nucleus RNA-sequencing of microdissected grafts. Notably, downregulation of OPN in engrafted FTD neurons resulted in improved engraftment and reduced microglial infiltration, indicating an immune-modulatory role of OPN in patient neurons, which may represent a potential therapeutic target in FTD.
Project description:Frontotemporal dementia (FTD) is an incurable group of early-onset dementias that can be caused by deposition of hyperphosphorylated tau in patient brains. However, the mechanisms leading to neurodegeneration remain largely unknown. Here, we combined single-cell analyses of FTD patient brains with a stem cell culture and transplantation model of FTD. We identified disease phenotypes in FTD neurons carrying the MAPT-N279K mutation, which were related to oxidative stress, oxidative phosphorylation and neuroinflammation with an upregulation of the inflammation-associated protein osteopontin (OPN). Human FTD neurons survived less and elicited an increased microglial response after transplantation into the mouse forebrain, that we further characterized by single nucleus RNA-sequencing of microdissected grafts. Notably, downregulation of OPN in engrafted FTD neurons resulted in improved engraftment and reduced microglial infiltration, indicating an immune-modulatory role of OPN in patient neurons, which may represent a potential therapeutic target in FTD.