Diversity of early astrocyte reactive profiles in familial amyotrophic lateral sclerosis
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ABSTRACT: Amyotrophic lateral sclerosis (ALS) is a rapidly progressive and fatal disease. Although astrocytes are increasingly recognized contributors to the underlying pathogenesis, the uniformity of their reactive transformation in different genetic forms of ALS remains unresolved. Here we begin to systematically examine this issue by performing RNA sequencing on highly enriched and serum-free human induced pluripotent stem cell derived astrocytes from patients with VCP, SOD1 and FUS mutations. The RNA-seq samples in this collection have been used to reveal that diverse fALS mutations lead to molecularly distinct reactive transformation in their basal state.
Project description:This datased was used to obtain a genome-wide expression signature for the early response of mouse motor neurons to mutant SOD1 astrocytes conditioned media. Neurons, far from living in isolation, are surrounded by a host of other neuronal and non-neuronal cells, such as astrocytes. The latter entertain complex functional interactions with neighboring neurons, which, under normal conditions, are important for the their well-being. In pathological situations, however, altered astrocyte behavior may contribute to the demise of neighboring neurons. Such non-cell autonomous pathogenic scenario is increasingly considered in a variety of disorders, including amyotrophic lateral sclerosis (ALS), the most frequent adult-onset paralytic disorder. Assembly and interrogation of gene regulatory models has helped elucidate causal mechanisms responsible for the presentation of several tumor-related phenotypes. To systematically elucidate the effectors of neurodegeneration in a model of ALS, we first developed techniques for the efficient purification of motor neurons (MNs), the primary target of ALS neurodegenerative process. We then generated gene expression profiles to fully characterize the critical timepoints associated with initiation and commitment of MN degenerative progression in an in vitro murine mutant SOD1 (mSOD1) model of ALS. ES cells were derived from transgenic Hlxb9-GFP1Tmj mice expressing eGFP and CD2 driven by the mouse HB9 promoter. These cells were then differentiated into motor neurons (ES-MN) as described previously [PMID 12176325] ES-MN were exposed to non-transgenic (NTg), G93A mutant SOD1 (mSOD1) or wtSOD1 over-expression astrocytes conditioned media for 0 days (time zero control), 1 day, and 3 days. Total RNA was extracted and profiled by RNAseq.
Project description:Total RNAs extracted from iPSC-astrocytes or iPSC-BMEC like cells grown together or separately in transwells were collected and analyzed using RNA sequencing. In addition, total RNAs extracted from conditions with or without TNF-a were analyzed.
Project description:Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease whose pathophysiology is largely unknown. Despite motor neuron death is recognized as the key event in ALS, astrocytes dysfunctionalities and neuroinflammation were demonstrated to accompany and probably even drive motor neuron loss. Nevertheless, the mechanisms priming astrocyte failure and hyperactivation are still obscure. In this work, altered pathways in ALS astrocytes were unveiled by investigating the proteomic profile of primary spinal-cord astrocytes derived from transgenic ALS mouse model overexpressing the human (h)SOD1(G93A) protein, in comparison with the transgenic counterpart expressing hSOD1(WT) protein. In this research, we showed that hSOD1(G93A) astrocytes present a profound alterations in the expression of proteins involved in proteostasis and glutathione metabolism.
Project description:Ectopic expression of the reprogramming factors OCT4, SOX2, or NANOG into human astrocytes in specific cytokine/culture conditions activated the neural stem gene program and induced generation of cells expressing neural stem/precursor markers (ASTRO-NSC). To evaluate the epigenetic changes associated with this reprogramming, we analyzed the DNA methylation patterns of Astro-NSC relative to untransfected astrocytes. We compared three human AstroNANOG-NSC clones to the astrocytes from which they were derived using NimbleGen 3x720K CpG Island Plus RefSeq Promoter Arrays
Project description:Bulk RNA-sequencing of astrocytes in the APP NL-F and APP PS1 models of ß-amyloidopathy, in which aspects of AD-related pathology progress at different speed, shows age-dependent gene expression changes. However, bulk RNA-seq does not provide insight into the heterogeneity of expression within this cell type, particularly relevant for such models, where reactive astrogliosis is most prominent in the vicinity of plaques. To investigate astrocyte heterogeneity in ß-amyloidopathy models, we thus performed single cell RNA-sequencing on astrocytes separated by FACS.
Project description:Transcriptional profiling of mouse primary astrocytes comparing control untreated astrocytes with astrocytes treated with recombinant LCN2 protein (10 micro gram/ml). Goal was to determine the effects of LCN2 treatment on global gene expression in astrocytes. A secreted protein lipocalin-2 (LCN2) has been implicated in diverse cellular processes including cell morphology and migration. We have previously demonstrated that lcn2 mediates reactive astrocytosis. In order to further understand the role of lcn2 in the CNS, astrocyte transcriptome was analyzed following LCN2 treatment. Chemokines were the major group of genes upregulated by LCN2. Two-condition experiment, control untreated astrocytes vs. LCN2 protein treated astrocytes. Biological replicates: 1 control replicates, 1 treated replicates.
Project description:This project studies TDP43, which is an RNA binding protein implicated in Motor Neuron Disease. As an RNA-binding protein, TDP43 is known to influences poly-adenylation site choice. For this project, we have inserted a single copy of the GFP-tagged TDP43 gene into the FLPIn Locus of HEk293 cells. We use these Hek293 FLipIn lines to instigate the effect of different deletion and mutation constructs of TDP-43 in their ability to rescue the depletion (siRNA) of the endogenous TDP-43 protein. We are comparing siRNA mediated KD in triplicates for each of the 7 cell lines to the Dox-induced rescues in triplicates. We are using a customised Lexogen Quantseq 3’ end sequencing method that allows us to multiplex cDNAs straight after the reverse transcription. The samples were pooled into barcoded sub-groups, each group will have the Lexogen barcode (i7 indices) in addition.
Project description:Reactive astrocytes are implicated in Amyotrophic Lateral Sclerosis (ALS), although the mechanisms controlling reactive transformation are unknown. We show that decreased intron retention (IR) is common to human induced pluripotent stem cell (hiPSC)-derived astrocytes carrying VCP, C9orf72 and SOD1 ALS-causing mutations as well as astrocytes stimulated to undergo reactive transformation. Notably, transcripts with decreased IR and increased expression are overrepresented in reactivity processes including cell-adhesion, stress-response, and immune-activation. We examined astrocyte translatome sequencing (TRAP-seq) from a SOD1 mouse model, which revealed a significant number of transcripts with reduced IR in ALS are upregulated in translation. Using nucleo-cytoplasmic fractionation of VCP astrocytes coupled with mRNA sequencing and proteomics, we identify that decreased IR in nuclear-detained transcripts is associated with increased cytoplasmic expression of genes and proteins encoding regulators of reactivity - indicating nuclear-to-cytoplasmic translocation and translation of spliced reactivity-related transcripts. These results provide novel insights into the molecular factors controlling the reactive transformation of ALS astrocytes.
Project description:Expression profiles for Gfap-positive astrocytes obtained by in vitro differentiation of 129SvJae x C57BL/6 murine embryonic stem (ES) cells. Generated to examine the relationship between expression levels and DNA methylation patterns. Experiment Overall Design: 3 replicates of ES-derived astrocytes.