ABSTRACT: TDP-43 is an important RNA binding protein. To better understand its binding targets in human neurons, we performed TDP-43 iCLIP on SHSY5Y cells.
Project description:UNC13A contains a novel cryptic exon which is expressed upon TDP-43 knockdown. However, it also features TDP-43 regulated intron retention of a downstream intron. To investigate the correlation of these two events, we performed Nanopore sequencing of amplicons from SHSY5Y cells with inducible TDP-43 knockdown, and FTD patient RNA samples
Project description:A stable HEK293 FlpIn T-Rex cells expressing TDP-43 with an N-terminal eGFP-tag was generated that allowed inducible physiological expression of the protein (Ling et al. 2010). Duplicate iCLIP experiments were performed using an antibody targeting eGFP (Abcam ab290). Crosslinked RNA-protein complexes were isolated by immuno-precipitation and cDNAs were generated to allow preparation of Illumina compatible DNA libraries as described in Huppertz et al. (2014).
Project description:In recent times, high throughput screening analyses have broadly defined the RNA cellular targets of TDP-43, a nuclear factor involved in neurodegeneration. A common outcome of all these studies is that changing the expression levels of this protein can alter the expression of several hundred RNAs within cells. What still remains to be clarified is which changes represent direct cellular targets of TDP-43 or just secondary variations due to the general role played by this protein in RNA metabolism. Using a HTS-based splicing junction analysis we have now identified 162 splicing events that are consistent with being directly controlled by TDP-43. Validation of the data, both in neuronal and non-neuronal cell lines demonstrated that TDP-43 substantially alters the levels of isoform expression in four genes potentially important for neuropathology: MADD/IG20, STAG2, FNIP1, and BRD8. Most importantly, for MADD/IG20 and STAG2 these changes could also be confirmed at the protein level. These alterations were also observed in a cellular model that successfully mimics TDP-43 loss of function effects following its aggregation. These novel splicing events may represent potential biomarkers to predict disease onset, progression, and to test the efficacy of novel therapeutic agents to recover TDP-43 functional properties. We have performed an HTS-based splicing junction analysis of a series of stable cell lines that lack TDP-43, overexpress this factor, or express an RNA-binding mutant, in order to find splicing events, potentially associated with neurodegenerativce diseases, regulated by this splicing factor. Samples were analyzed in triplicate from: The following samples were analyzed in triplicate: wild-type HEK-293 cells, siTDP43-treated HEK-293 cells, siTDP43-treated HEK-293 cells overexpressing a flagged-wildtype TDP-43, siTDP43-treated HEK-293 cells overexpressing a RNA-binding deficient mutant.
Project description:To investigate how translation changed as a function of TDP-43 CR loss, mass spectrometry (MS) based approach was performed to monitor the dynamics of TDP-43-associated protein complexes in response to CR deletion using TDP-43 knockout HEK293 cells expressing strep tagged wild type TDP-43 (TDP-43WT) or TDP-43ΔCR mutant.
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: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:Neurodegeneration in ALS and FTD results from both gain of toxicity and loss of normal function of the RNA-binding protein TDP-43, but their mechanistic connection remains unclear. Increasing evidence suggests that TDP-43 aggregates act as self-templating seeds, propagating pathology through the central nervous system via a prion-like cascade. We developed a robust TDP-43 seeding platform for quantitative, high-throughput assessment of TDP-43 aggregate uptake, cell-to-cell spreading and loss of function within living cells, while they progress towards pathology. We show that both patient-derived and recombinant TDP-43 pathological aggregates were abundantly internalized in human neuron-like cells, efficiently recruited endogenous TDP-43 and formed cytoplasmic inclusions reminiscent of ALS/FTD pathology. These neoaggregates progressively drove the nuclear egress of TDP-43 leading to its loss of function. Our model demonstrates the link between TDP-43 aggregation and aberrant cryptic splicing and provides new tools to identify genetic or pharmacologic modifiers of each step in the process.