ABSTRACT: Transgenic (Tg) mice expressing nuclear or cytoplasmic human TDP-43 were generated. Tg mice had motor spasticity and forebrain neurodegeneration. Human TDP-43 reduced mouse TDP-43 in nuclei of affected neurons. Tg mice showed alterations in transcripts related to chromatin assembly. Cerebral cortex from 21 transgenic mice and controls were assayed after two weeks off doxycyline diet as described in Igaz et al.
Project description:Transgenic (Tg) mice expressing nuclear or cytoplasmic human TDP-43 were generated. Tg mice had motor spasticity and forebrain neurodegeneration. Human TDP-43 reduced mouse TDP-43 in nuclei of affected neurons. Tg mice showed alterations in transcripts related to chromatin assembly.
Project description:Transactive response DNA-binding protein of 43 kDa (TDP-43), a heterogeneous nuclear ribonucleoprotein (hnRNP) with diverse activities, is a common denominator in several neurodegenerative disorders including amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Orthologs of TDP-43 exist from mammals to invertebrates, but their functions in lower organisms remain poorly understood. Here we systematically studied mutant Caenorhabditis elegans lacking the nematode TDP-43 ortholog, TDP-1. To understand the global gene expression regulation induced by the loss of tdp-1, the C. elegans transcriptomes were compared between the N2 WT animals and the tdp-1(ok803lf) mutant. Transcriptional profiling demonstrated that the loss of TDP-1 altered expression of genes functioning in RNA processing and protein folding. These results suggest that the C. elegans TDP-1 as an RNA-processing protein may have a role in the regulation of protein homeostasis and aging. Global gene expression profiling was performed to compare the transcriptome of wild-type (N2) Caenorabditis elegans and that of tdp-1(ok803) loss-of-function mutant. We analyzed mixed stages of Caenorabditis elegans, wild-type N2 versus tdp-1(ok803), using the Affymetrix C. elegans genome array. Three biological replicates were performed.
Project description:We identify the RNA targets of TAR DNA-binding protein 43 (TDP-43) from cortical neurons by RNA immunoprecipitation followed by deep sequencing (RIP-seq). We identify 4352 highly enriched RNA targets of TDP-43. We determined that the canonical TDP-43 binding site (TG)n was 55.1-fold enriched in our TDP-43 library. Moreover, our analysis shows there is often an adenine in the middle of the motif, (TG)nTA(TG)m. TDP-43 RNA targets are particularly enriched for Gene Ontology terms related to RNA metabolism, neuronal development, and synaptic function.
Project description:We identify the RNA targets of TAR DNA-binding protein 43 (TDP-43) from cortical neurons by RNA immunoprecipitation followed by deep sequencing (RIP-seq). We identify 4352 highly enriched RNA targets of TDP-43. We determined that the canonical TDP-43 binding site (TG)n was 55.1-fold enriched in our TDP-43 library. Moreover, our analysis shows there is often an adenine in the middle of the motif, (TG)nTA(TG)m. TDP-43 RNA targets are particularly enriched for Gene Ontology terms related to RNA metabolism, neuronal development, and synaptic function. Examination of TDP-43 RNA targets in rat cortical neurons by RIP-seq. Chantelle F. Sephton isolated the TDP-43:RNA complexes and generated the cDNA library for deep sequencing. Email: chantelle.sephton@utsouthwestern.edu Phone: 214-648-4119 Fax: 214-648-1801 ULR: http://www8.utsouthwestern.edu/utsw/cda/dept120915/files/151135.html Organization name: University of Texas Southwestern Medical Center at Dallas Department: Neuroscience Lab: Gang Yu lab Street: 6000 Harry Hines Blvd. City: Dallas State: Texas ZIP: 75390 Country: USA
Project description:The TMEM106B gene, encoding a lysosomal membrane protein, is closely linked with brain aging and neurodegeneration. TMEM106B has been identified as a risk factor for several neurodegenerative diseases characterized by aggregation of the RNA-binding protein TDP-43, including frontotemporal lobar degeneration (FTLD) and limbic-predominant age-related TDP-43 encephalopathy (LATE). To investigate the role of TMEM106B in TDP-43 proteinopathy, we ablated TMEM106B in the TDP-43Q331K knock-in mouse line, which expresses an ALS-linked TDP-43 mutation at endogenous levels. We found that TMEM106B deficiency leads to glial activation, Purkinje cell loss, and behavioral deficits in TDP-43Q331K mice without inducing typical TDP-43 pathology. Interestingly, ablation of TMEM106B results in significant body weight gain, increased fat deposition, and hepatic triglyceride (TG) accumulation in TDP-43Q331K mice. In addition, lipidomic and transcriptome analysis shows a profound alteration in lipid metabolism in the liver of TDP-43Q331KTmem106b-/- mice. Our studies reveal a novel function of TMEM106B and TDP-43 in lipid metabolism and provide new insights into their roles in neurodegeneration.
Project description:Mutations in TDP-43 (an RNA binding protein) are known to cause amyotrophic lateral sclerosis (ALS). Previously, our group and several other studies showed that TDP-43 binds to several RNA targets in the mammalian CNS. ALS causing mutations in the C-terminal region of TDP-43 that is involved in splicing regulation may lead to aberrant splicing of several RNA transcripts. The main aim of this study is to identify the effect of an ALS causing mutation on the splicing regulation of previously known targets of TDP-43. Mice overexpressing a mutant human TDP-43 (hTDP-43) gene were obtained from The Jackson Laboratory (strain name - B6;CB-Tg(Prnp-TARDBP*A315T) 95Balo/J; Stock no:010700). Mutant hTDP43 was expressed under the control of a prion protein promoter that drives the expression mainly in the mouse CNS and the male transgenic mice developed symptoms around 12 weeks of age while the female mice develop symptoms approximately 20 weeks of age. Therefore, Tg animals that are 50 days old were considered pre-symptomatic and 100 days old (Tg) animals were considered to be in the post-symptomatic stages of the disease for exon array experiments. Age and sex matched pre and post-symptomatic transgenic animals and their wild type littermates were euthanised by cervical dislocation and tissues (brain and spinal cord) were harvested immediately for total RNA isolation experiments (n=3 per group). 200 ng of total RNA from transgenic TDP-43 mice and wild type animals was converted to cDNA and then amplified using the Applause WT-Amp Plus ST kit (NuGEN). Amplified cDNA was then fragmented and biotin labeled using the Encore Biotin Module kit (NuGEN) according to the manufacturer's instruction manual. Labelled cDNA was then hybridised onto Affymetrix GeneChip Exon 1.0 ST arrays in a hybridisation oven at 45 degrees C for 20 hours at 60rpm. After hybridization, washing and staining of the arrays were carried out using Affymetrix fluidics station 450 followed by scanning using GeneChip scanner. GeneChip Command Console Software (AGCC) controlled both the fluidics station and the scanner. CEL files generated by AGCC were uploaded onto Partek software and the data analysis was carried out using the exon array analysis workflow. Exon 1.0 ST arrays contain many more probes, which are classified into three major types based on their source. They are Core, extended and full probe set annotation. Core annotation refers the probe sets that are the most reliable of the three and is derived based on evidences from Refseq and GenBank. Extended annotations refer to probe sets that are generated based on EST sequences, ENSEMBL gene collections and other databases including those used for generating core probe sets. The full annotation refers to probe sets that are purely based on computational predictions. Core probe set annotation, unlike the extended or full annotation excludes the speculative probes reducing the incidence of false positives and was employed for exon array analysis. Alt-splice Anova, a statistical tool available in Partek was used for identifying novel alternative splicing events.
Project description:The TMEM106B gene, encoding a lysosomal membrane protein, is closely linked with brain aging and neurodegeneration. TMEM106B has been identified as a risk factor for several neurodegenerative diseases characterized by aggregation of the RNA-binding protein TDP-43, including frontotemporal lobar degeneration (FTLD) and limbic-predominant age-related TDP-43 encephalopathy (LATE). To investigate the role of TMEM106B in TDP-43 proteinopathy, we ablated TMEM106B in the TDP-43Q331K knock-in mouse line, which expresses an ALS-linked TDP-43 mutation at endogenous levels. We found that TMEM106B deficiency leads to glial activation, Purkinje cell loss, and behavioral deficits in TDP-43Q331K mice without inducing typical TDP-43 pathology. Interestingly, ablation of TMEM106B results in significant body weight gain, increased fat deposition, and hepatic triglyceride (TG) accumulation in TDP-43Q331K mice. In addition, lipidomic and transcriptome analysis shows a profound alteration in lipid metabolism in the liver of TDP-43Q331KTmem106b-/- mice. Our studies reveal a novel function of TMEM106B and TDP-43 in lipid metabolism and provide new insights into their roles in neurodegeneration.
Project description:TDP-43, a DNA/RNA binding protein involved in RNA transcription and splicing has been associated with the pathophysiology of neurodegenerative diseases, including ALS. However, the function of TDP-43 in motor neurons remains undefined. Here, we employ both gain- and loss-of-function approaches to determine roles of TDP-43 in motor neurons. Mice expressing human TDP-43 in neurons exhibited growth retardation and premature death that are characterized by abnormal intranuclear inclusions comprised of TDP-43 and Fused in Sarcoma (FUS), and massive accumulation of mitochondria in TDP-43-negative cytoplasmic inclusions in motor neurons, lack of mitochondria in motor axon terminals and immature neuromuscular junctions. Whereas elevated level of TDP-43 disrupts the normal nuclear distribution of Survival Motor Neuron (SMN)-associated Gemini of coiled bodies (GEMs) in motor neurons, its absence prevents the formation of GEMs in the nuclei of these cells. Moreover, transcriptome-wide deep sequencing analysis revealed that decrease in abundance of neurofilament transcripts contributed to the reduction of caliber of motor axons in TDP-43 mice. In concert, our findings indicate that TDP-43 participates in pathways critical for motor neuron physiology, including those that regulate the normal distributions of SMN-associated GEMs in the nucleus and mitochondria in the cytoplasm. Human TDP-43 coding region were inserted into pThy1.2 expression cassette and subsequently injected into C57BL/6;SJL hybrid mouse embryos to make human TDP-43 transgenic mice
Project description:MicroRNAs (miRNAs) play important roles in a wide range of cellular processes. Aberrant regulation of miRNA genes contributes to human diseases, including cancer. The TAR DNA binding protein 43 (TDP-43), a DNA/RNA binding protein associated with neurodegeneration, is involved in miRNA biogenesis. Here, we systematically examined miRNAs whose expression levels are regulated by TDP-43 using RNA-Seq coupled with siRNA-mediated knockdown approach. TDP-43 knocking down affected the expression of a number of miRNAs. Alterations in isomiR patterns and miRNA arm selection after TDP-43 knockdown suggest a role of TDP-43 in miRNA editing. We examined correlation of selected TDP-43 associated miRNAs and their candidate target genes in human cancers. Our data reveal highly complex roles of TDP-43 in regulating different miRNAs and their target genes. Our results suggest that TDP-43 may promote migration of lung cancer cells by regulating miR-423-3p expression. On the other hand, TDP-43 increases miR-500a-3p expression and binds to the mature miR-500a-3p sequence. Low expression of miR-500a-3p was associated with poor survival of lung cancer patients, suggesting that TDP-43 may have a suppressive role in cancer by regulating miR-500a-3p. Our experiments reveal that cancer-associated genes LIF and PAPPA may be targets of miR-500a-3p. Together with other studies, our work suggests that TDP-43-regulated miRNAs may play multi-facet roles in the pathogenesis of cancer. small RNA seq in SH-SY-5Y, SNB-19 and HT22 (TDP-43 siRNA VS Control siRNA)
Project description:Nuclear clearance of TDP-43 into cytoplasmic aggregates is a key driver of neurodegeneration in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), but the mechanisms are unclear. Here, we show that TDP-43 knockdown specifically reduces number and motility of RAB11-positive recycling endosomes in dendrites, while TDP-43 overexpression has the opposite effect. This is associated with delayed transferrin recycling in TDP-43 knockdown neurons and decreased 2-transferrin levels in patient CSF. Whole proteome quantification identified upregulation of the ESCRT component VPS4B upon TDP-43 knockdown in neurons. Luciferase report assays and chromatin immunoprecipitation suggest that TDP-43 represses VPS4B transcription. Preventing VPS4B upregulation or expression of its functional antagonist ALIX restores trafficking of recycling endosomes. Proteomic analysis revealed broad reduction in surface expression of key receptors upon TDP-43 knockdown including ErbB4, the neuregulin 1 receptor. TDP-43 knockdown delays surface delivery of ErbB4. ErbB4 overexpression, but not neuregulin 1 stimulation, prevents dendrite loss upon TDP-43 knockdown. Thus, impaired recycling of ErbB4 and other receptors to the cell surface may contribute to TDP-43 induced neurodegeneration by blocking trophic signaling.