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: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:We performed bulk RNA-seq on FACS-isolated oligodendrocytes from P30 Mobp-TDP43 and Mog-TDP43 mouse lines to determine the effect of TDP-43 loss at different stages of oligodendrocyte development.
Project description:TDP-43 protein plays an important role in regulating transcriptional repression, RNA metabolism, and splicing. Typically it shuttles between the nucleus and the cytoplasm to perform its functions, while abnormal cytoplasmic aggregation of TDP-43 has been associated with neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). For the purpose of this study we selected a set of proteins that were misregulated following silencing of TDP-43 and analysed their expression in a TDP-43-aggregation model cell line HEK293 Flp-in Flag-TDP-43-12x-Q/N F4L. Following TDP-43 sequestration in insoluble aggregates, we observed higher nuclear levels of EIF4A3, and POLDIP3?, whereas nuclear levels of DNMT3A, HNRNPA3, PABPC1 and POLDIP3? dropped, and cytoplasmic levels of RANBP1 dropped. In addition, immunofluorescence signal intensity quantifications showed increased nuclear expression of HNRNPL and YARS, and downregulation of cytoplasmic DPCD. Furthermore, cytoplasmic levels of predominantly nuclear protein ALYREF increased. In conclusion, by identifying a common set of proteins that are differentially expressed in a similar manner in these two different conditions, we show that TDP-43 aggregation has a comparable effect to TDP-43 knockdown.
Project description:Exploring the intricate link between sleep and brain degeneration holds great promise for the development of effective therapeutics. Here we provide novel insights into the role of TDP-43 and Atx2 in regulating sleep and neurodegeneration using Drosophila. We demonstrate that expression of TDP-43 severely disrupts sleep, resulting in reduced sleep duration of the affected animals. Sleep disruption by TDP-43 is completely rescued by Atx2 knockdown. To unravel the underlying mechanism of TDP43 sleep disruption and Atx2-mediated rescue, we conducted brain RNA sequencing analysis from flies expressing TDP-43 with or without Atx2 knockdown. Among RNAseq changes, we observed upregulation of genes associated with small molecule metabolism with TDP-43 expression, followed by their subsequent downregulation upon Atx2 knockdown. Utilizing these Atx2-regulated genes, we conducted an RNAi screen to identify additional sleep modifiers that interact with TDP-43.
Project description:Depletion of amyotrophic lateral sclerosis (ALS)-associated transactivation response (TAR) RNA/DNA-binding protein 43 kDa (TDP-43) alters splicing efficiency of multiple transcripts and results in neuronal cell death. TDP-43 depletion can also disturb expression levels of small nuclear RNAs (snRNAs) as spliceosomal components. Despite this knowledge, the relationship between cell death and alteration of snRNA expression during TDP-43 depletion remains unclear. Here, we knocked down TDP-43 in murine neuroblastoma Neuro2A cells and found a time lag between efficient TDP-43 depletion and appearance of cell death, suggesting that several mechanisms mediate between these two events. The amount of U6 snRNA was significantly decreased during TDP-43 depletion prior to increase of cell death, whereas that of U1, U2, and U4 snRNAs was not. Downregulation of U6 snRNA led to cell death, whereas transient exogenous expression of U6 snRNA counteracted the effect of TDP-43 knockdown on cell death, and slightly decreased the mis-splicing rate of Dnajc5 and Sortilin 1 transcripts, which are assisted by TDP-43. These results suggest that regulation of the U6 snRNA expression level by TDP-43 is a key factor in the increase in cell death upon TDP-43 loss-of-function.
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:TDP-43 is an RNA/DNA-binding protein implicated in transcriptional repression and mRNA processing. Inclusions of TDP-43 are hallmarks of frontotemporal dementia and amyotrophic lateral sclerosis. Besides aggregation of TDP-43, loss of nuclear localization is observed in disease. To identify relevant targets of TDP-43, we performed expression profiling. Thereby, histone deacetylase 6 (HDAC6) downregulation was discovered on TDP-43 silencing and confirmed at the mRNA and protein level in human embryonic kidney HEK293E and neuronal SH-SY5Y cells. This was accompanied by accumulation of the major HDAC6 substrate, acetyl-tubulin. HDAC6 levels were restored by re-expression of TDP-43, dependent on RNA binding and the C-terminal protein interaction domains. Moreover, TDP-43 bound specifically to HDAC6 mRNA arguing for a direct functional interaction. Importantly, in vivo validation in TDP-43 knockout Drosophila melanogaster confirmed the specific downregulation of HDAC6. HDAC6 is necessary for protein aggregate formation and degradation. Indeed, HDAC6-dependent reduction of cellular aggregate formation and increased cytotoxicity of polyQ-expanded ataxin-3 were found in TDP-43 silenced cells. In conclusion, loss of functional TDP-43 causes HDAC6 downregulation and might thereby contribute to pathogenesis.