Project description:RNA sequencing analysis of human iPSC-derived motor neurons generated from one C9ORF72 ALS/FTD patient line, treated with DMSO or Apilimod. The goal of this study is to evaluate the effect of PIKFYVE inhibitor in rescuing ALS motor neuron degeneration.
Project description:We have generated human induced Pluripotent Stem cells (hiPSc) from amyotrophic lateral sclerosis (ALS, motor neuron disease) patients, using Sendai virus-mediated delivery of reprogramming factors. hiPSc lines have been screened using SNP array to assess chromosomal stability (alongside the fibroblast lines from which they derived), and validation of the pluripotency of the hiPSc lines is provided by Pluritest assessment of transcriptome datasets, prior to differentiation to motor neuron cultures and downstream functional assays. Mutihac R., Scaber J., Lalic T., Ababneh N., Vowles, J., Fletcher-Jones A., Douglas A.G.L., Browne C., Nakanishi M., Turner M., Wade-Martins R., Cowley S.A. and Talbot K. Altered ER calcium homeostasis and stress granule formation in iPSC-derived motor neurons from ALS/FTD patients with C9orf72 expansions. Submitted
Project description:RNA sequencing analysis of human iPSC-derived motor neurons generated from two C9ORF72 ALS/FTD patient lines, treated with negative control ASO (NC ASO) or PIKFYVE ASO. The goal of this study is to evaluate the effect of PIKFYVE suppression in rescuing ALS motor neuron degeneration.
Project description:We have generated human induced Pluripotent Stem cells (hiPSc) from amyotrophic lateral sclerosis (ALS, motor neuron disease) patients, using Sendai virus-mediated delivery of reprogramming factors. hiPSc lines have been screened using SNP array to assess chromosomal stability (alongside the fibroblast lines from which they derived), and validation of the pluripotency of the hiPSc lines is provided by Pluritest assessment of transcriptome datasets, prior to differentiation to motor neuron cultures and downstream functional assays. Mutihac R., Scaber J., Lalic T., Ababneh N., Vowles, J., Fletcher-Jones A., Douglas A.G.L., Browne C., Nakanishi M., Turner M., Wade-Martins R., Cowley S.A. and Talbot K. Altered ER calcium homeostasis and stress granule formation in iPSC-derived motor neurons from ALS/FTD patients with C9orf72 expansions. Submitted
Project description:Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative condition characterized by loss of motor neurons in the brain and spinal cord. Expansions of a hexanucleotide repeat (GGGGCC) in the noncoding region of the C9ORF72 gene are the most common cause of the familial form of ALS (C9-ALS), as well as frontotemporal lobar degeneration and other neurological diseases. How the repeat expansion causes disease remains unclear, with both loss of function (haploinsufficiency) and gain of function (either toxic RNA or protein products) proposed. We report a cellular model of C9-ALS with motor neurons differentiated from induced pluripotent stem cells (iPSCs) derived from ALS patients carrying the C9ORF72 repeat expansion. No significant loss of C9ORF72 expression was observed, and knockdown of the transcript was not toxic to cultured human motor neurons. Transcription of the repeat was increased, leading to accumulation of GGGGCC repeat–containing RNA foci selectively in C9-ALS iPSC-derived motor neurons. Repeat-containing RNA foci colocalized with hnRNPA1 and Pur-?, suggesting that they may be able to alter RNA metabolism. C9-ALS motor neurons showed altered expression of genes involved in membrane excitability including DPP6, and demonstrated a diminished capacity to fire continuous spikes upon depolarization compared to control motor neurons. Antisense oligonucleotides targeting the C9ORF72 transcript suppressed RNA foci formation and reversed gene expression alterations in C9-ALS motor neurons. These data show that patient-derived motor neurons can be used to delineate pathogenic events in ALS. Transcriptome profiling from iPSC derived motor neurons compared to controls
Project description:Expansions of a hexanucleotide repeat (GGGGCC) in the noncoding region of the C9orf72 gene are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. Decreased expression of C9orf72 is seen in expansion carriers, suggesting loss of function may play a role in disease. We find that two independent mouse lines lacking the C9orf72 ortholog (3110043O21Rik) in all tissues developed normally and aged without motor neuron disease. Instead, C9orf72 null mice developed progressive splenomegaly and lymphadenopathy with accumulation of engorged macrophage-like cells. C9orf72 expression was highest in myeloid cells, and loss of C9orf72 led to lysosomal accumulation and altered immune responses in macrophages and microglia, with age-related neuroinflammation similar to C9orf72 ALS but not sporadic ALS patient tissue. Thus, C9orf72 is required for normal function of myeloid cells, and altered microglial function may contribute to neurodegeneration in C9orf72 expansion carriers.
Project description:To differentiate, characterize and examine intrinsic phenotypes of C9orf72 ALS/FTD patient-derived induced pluripotent stem cells into microglia (iPSC-MG). Moderate molecular and functional differences were observed in C9orf72 iPSC-MG mono-cultures despite the presence of C9orf72 pathological features.
Project description:Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive motor neuron loss, with additional pathophysiological involvement of non-neuronal cells such as microglia. The commonest ALS-associated genetic variant is a hexanucleotide repeat expansion (HRE) mutation in C9orf72. Here, we study its consequences for microglial function using human iPSC-derived microglia. By RNA-sequencing, we identify enrichment of pathways associated with immune cell activation and cyto-/chemokines in C9orf72 HRE mutant microglia versus healthy controls, most prominently after LPS priming. Specifically, LPS-primed C9orf72 HRE mutant microglia show consistently increased expression and release of matrix metalloproteinase-9 (MMP9). LPS-primed C9orf72 HRE mutant microglia are toxic to co-cultured healthy motor neurons, which is ameliorated by concomitant application of an MMP9 inhibitor. Finally, we identify release of dipeptidyl peptidase-4 (DPP4) as a marker for MMP9-dependent microglial dysregulation in co-culture. These results demonstrate cellular dysfunction of C9orf72 HRE mutant microglia, and a non-cell-autonomous role in driving C9orf72-ALS pathophysiology in motor neurons through MMP9 signaling.
Project description:A GGGGCC repeat expansion in C9orf72 is the most common genetic cause of ALS and FTD (C9ALS/FTD). Dipeptide repeat (DPR) proteins, generated by translation of the expanded repeat, are a major pathogenic feature of C9ALS/FTD pathology, but their physiological impact has yet to be fully determined. Here, we generated C9orf72 DPR knock-in mouse models characterised by expression of 400 codon-optimised polyGR or polyPR repeats, and heterozygous C9orf72 reduction. (GR)400 and (PR)400 knock-in mice recapitulate key features of C9ALS/FTD, including cortical neuronal hyperexcitability, age-dependent spinal motor neuron loss and progressive motor dysfunction. Quantitative proteomics revealed an increase in extracellular matrix (ECM) proteins in (GR)400 and (PR)400 spinal cord, with the collagen COL6A1 the most increased protein. This increase in ECM protein levels looked to be a conserved feature of C9ALS/FTD, with a similar signature also present in C9ALS patient iPSC-motor neurons. TGF-β1 was one of the top predicted regulators of this ECM signature and polyGR expression in human iPSC-neurons was sufficient to induce TGF-β1 followed by COL6A1. Knockdown of TGF-β1 or COL6A1 orthologues in polyGR model Drosophila exacerbated neurodegeneration, while expression of TGF-β1 or COL6A1 in C9ALS/FTD patient iPSC motor neurons protected against glutamate-induced cell death. Altogether, our C9orf72 DPR knock-in mice have revealed a neuroprotective and conserved ECM signature in C9ALS/FTD.