Project description:Here we analyse transcriptome profiles from laser captured lower motor neurons between wild type, heterozygous and homozygous TDP-43 Q331K knockin mice
Project description:Here we analyse transcriptome profiles within the frontal cortex between wild type, heterozygous and homozygous TDP-43 Q331K knockin mice at 20 months of age (C57BL/6)
Project description:Here we analyse transcriptome profiles within the frontal cortex between wild type, heterozygous and homozygous TDP-43 Q331K knock-in mice
Project description:A key pathological feature of Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD) is the loss of nuclear localization and accumulation of cytoplasmic inclusions of TAR-DNA binding protein 43 (TDP-43). TDP-43 is a nucleic acid-binding protein involved in transcriptional repression, mRNA splicing, and the regulation of retrotransposable elements (RTEs) and endogenous retroviruses (ERVs). RTEs/ERVs are mobile virus-like genetic elements that constitute about 45% of our genome and encode the capacity to replicate through an RNA intermediate and insert cDNA copies at de novo chromosomal locations. A causal role of RTEs/ERVs has been demonstrated in Drosophila in mediating both intracellular toxicity of TDP-43 and the intercellular spread of toxicity from glia to neurons. RTEs/ERVs are inappropriately expressed in postmortem tissues from ALS, FTD, and Alzheimer's Disease (AD) patients, but the role of RTEs/ERVs has not yet been examined in a vertebrate model of TDP-43 pathology. We utilized established transgenic mouse models that overexpress moderate levels of human wild-type TDP-43 or a mutant version with a specific ALS-causal Q331K amino acid substitution, together with a LINE-1-EGFP retrotransposon indicator line. We found that TDP-43 animals exhibit broad expression of RTEs/ERVs with LINE-1 retrotransposition in glia and neurons in the motor cortex. Expression begins with onset of neurological phenotypes, earlier in hTDP-43-Q331K animals and later in hTDP-43-WT. The LINE-1-EGFP retrotransposition reporter transiently labels spatially clustered groups of neurons and glia at the time of onset of motor symptoms, while EGFP-labeled neurons undergo cell death and are therefore lost over time. Unlabeled cells also die as a function of distance from the clusters of LINE-1-EGFP labeled neurons and glial cells. Together, these findings support the hypothesis that TDP-43 pathology triggers RTE/ERV expression in the motor cortex, that such expression marks cells for programmed cell death, with cell non-autonomous effects on nearby neurons and glial cells.
Project description:Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) share key features, including accumulation of the RNA binding protein TDP-43. TDP-43 regulates RNA homeostasis, but it remains unclear whether RNA stability is affected in these disorders. We use Bru-seq and BruChase-seq to assess genome-wide RNA stability in ALS patient-derived cells, demonstrating profound destabilization of ribosomal and mitochondrial transcripts. This pattern is recapitulated by TDP-43 overexpression, suggesting a primary role for TDP-43 in RNA destabilization, and in post-mortem samples from ALS and FTD patients. Proteomics and functional studies illustrate corresponding reductions in mitochondrial components and compensatory increases in protein synthesis. Collectively, these observations suggest that TDP-43 deposition leads to targeted RNA instability in ALS and FTD, and may ultimately cause cell death by disrupting energy production and protein synthesis pathways.
Project description:The aim of this study is to understand the mechanisms of TDP-43 neurotoxicity. Here, we perform a RNA-Seq analysis in TDP-43 gain-of-fucntion (GOF) , TDP-43 loss-of-function and wild-type late pupae heads (73-90 hours APF) and perform TDP-43 GOF vs wild type and TDP-43 LOF vs wild-type differential expression analysis to show that both mechanisms presents defects in ecdysone receptor (ECR)-dependeint transcriptional program switching, and strongly deregulate expression from the neuronal microtubule associated protien Map205. RNA-seq was performed in two wild-type D.melanogaster biological replicates (Canton S, w1118 ), four biological replicates for TDP-43 (LOF) with two distinct genotypes (dTDP-43Δ142/Df(2R)106,dTDP-43Δ23/Δ142 ) and two TDP-43 GOF biological replicates (act5c>dTDP-43 ).