TDP-43 represses cryptic exon inclusion in FTD/ALS gene UNC13A
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ABSTRACT:
PROVIDER: PRJNA758574 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR15661976_1.fastq.gz | Fastqsanger.gz | |||
| SRR15661976_2.fastq.gz | Fastqsanger.gz | |||
| SRR15661977_1.fastq.gz | Fastqsanger.gz | |||
| SRR15661977_2.fastq.gz | Fastqsanger.gz | |||
| SRR15661978_1.fastq.gz | Fastqsanger.gz |
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Project description:Through splicing analysis of a publicly available RNA-Seq dataset, we discovered TDP-43 represses a cryptic exon splicing event in UNC13A, a gene that had been associated with FTD/ALS through GWA studies. To confirm the sequences of the cryptic exons, we used shRNA to reduce TDP-43 levels in iPSC-derived motor neurons (iPSC-MNs) and by amplicon sequencing the RT-PCR product, we observed the insertion in cells with TDP-43 depletion but not in control shRNA-treated cells. Through sequence alignment, we verified the sequences of the cryptic exons.
2021-12-04 | GSE182976 | GEO
Project description:A hallmark pathological feature of the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is the depletion of RNA-binding protein TDP-43 from the nucleus of neurons in the brain and spinal cord1. A major function of TDP-43 is as a repressor of cryptic exon inclusion during RNA splicing2-4. Single nucleotide polymorphisms in UNC13A are among the strongest hits associated with FTD and ALS in human genome-wide association studies5,6, but how those variants increase risk for disease is unknown. Here we show that TDP-43 represses a cryptic exon-splicing event in UNC13A. Loss of TDP-43 from the nucleus in human brain, neuronal cell lines and motor neurons derived from induced pluripotent stem cells resulted in the inclusion of a cryptic exon in UNC13A mRNA and reduced UNC13A protein expression. The top variants associated with FTD or ALS risk in humans are located in the intron harbouring the cryptic exon, and we show that they increase UNC13A cryptic exon splicing in the face of TDP-43 dysfunction. Together, our data provide a direct functional link between one of the strongest genetic risk factors for FTD and ALS (UNC13A genetic variants), and loss of TDP-43 function.
| S-EPMC8891019 | biostudies-literature
Project description:A major function of TAR DNA-binding protein-43 (TDP-43) is to repress the inclusion of cryptic exons during RNA splicing. One of these cryptic exons is in UNC13A, a genetic risk factor for amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The accumulation of cryptic UNC13A in disease is heightened by the presence of a risk haplotype located within the cryptic exon itself. Here, we revealed that TDP-43 extreme N-terminus is important to repress UNC13A cryptic exon inclusion. Further, we found hnRNP L, hnRNP A1, and hnRNP A2B1 bind UNC13A RNA and repress cryptic exon inclusion, independently of TDP-43. Finally, higher levels of hnRNP L protein associate with lower burden of UNC13A cryptic RNA in ALS/FTD brains. Our findings suggest that while TDP-43 is the main repressor of UNC13A cryptic exon inclusion, other hnRNPs contribute to its regulation and may potentially function as disease modifiers.
| S-EPMC10057836 | biostudies-literature
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
2022-02-10 | E-MTAB-11244 | biostudies-arrayexpress
Project description:UNC13A contains a cryptic exon which is normally repressed by TDP-43. To better understand the mechanism by which TDP-43 represses this cryptic splicing, and how common SNPs (rs12973192(G) and rs12608932(C)) perturb this regulation, we transfected HEK293T cells with minigenes featuring UNC13A exons 20 and 21, and intron 20. We used two variants of the minigene: one with rs12973192(C) and rs12608932(G) (2x healthy) and the other with rs12973192(G) and rs12973192(C) (2x risk), then performed TDP-43 iCLIP on these cells. We used two replicates for each.
2022-03-24 | E-MTAB-10297 | biostudies-arrayexpress
Project description:Maintaining cholesterol homeostasis is essential for health of all animal cells. Because of blood-brain barrier, de novo cholesetrol biosynthesis and intercellular cholesterol transport is thought to maintain cholesterol homeostasis within the central nervous system (CNS). Here, we showed that TDP-43, the pathological signature protein for amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), regulates SREBF2-mediated cholesterol metabolism in the central nervous system (CNS). Unbiased transcriptomic analysis of mice with oligodendroglial TDP-43 deletion revealed a progressive and pathway-wide disruption in the cholesterol metabolism correlating with reduced myelination and cholesterol level. Molecularly, TDP-43 binds directly to mRNA of SREBF2, the master transcription regulator for cholesterol metabolism, and multiple mRNAs encoding proteins in the cholesterol biosynthesis and uptake, including HMGCR, HMGCS1, and LDLR. Depletion of TDP-43 leads to reduced SREBF2 and cholesterol level in vitro and in vivo. The cholesterol reduction can be rescued by reintroducing either the nuclear portion of SREBF2 or LDLR, the latter of which is the receptor for cholesterol-containing low-density lipoproteins (LDLs). Furthermore, LDLR are observed to co-aggregate with pathological TDP-43 in oligodendrocytes of FTD patients and motor neurons of sporadic ALS patients. Taken together, our data indicates that TDP-43 is required to maintain SREBF2-dependent cholesterol homeostasis in the CNS, and disturbance of cholesterol metabolism may be involved in ALS, FTD and TDP-43 proteinopathies-related disease.
2021-07-01 | GSE133047 | GEO
Project description:ALS/FTD GWAS risk variant rs12973192 promotes severe cryptic splicing of the UNC13A transcript upon TDP-43 depletion
| PRJEB42763 | ENA
Project description:Nuclear depletion and cytoplasmic aggregation of the RNA-binding protein TDP-43 is the hallmark of ALS, occurring in over 97% of cases. A key consequence of TDP-43 nuclear loss is the de-repression of cryptic exons. Whilst TDP-43 regulated cryptic splicing is increasingly well catalogued, cryptic alternative polyadenylation (APA) events, which define the 3' end of last exons, have been largely overlooked, especially when not associated with novel upstream splice junctions. We developed a novel bioinformatic approach to reliably identify distinct APA event types: alternative last exons (ALE), 3'UTR extensions (3'Ext) and intronic polyadenylation (IPA) events. We identified novel neuronal cryptic APA sites induced by TDP-43 loss of function by systematically applying our pipeline to a compendium of publicly available and in house datasets. We find that TDP-43 binding sites and target motifs are enriched at these cryptic events and that TDP-43 can have both repressive and enhancing action on APA. Importantly, all categories of cryptic APA can also be identified in ALS and FTD post mortem brain regions with TDP-43 proteinopathy underlining their potential disease relevance. RNA-seq and Ribo-seq analyses indicate that distinct cryptic APA categories have different downstream effects on transcript and translation. Intriguingly, cryptic 3'Exts occur in multiple transcription factors, such as ELK1, SIX3, and TLX1, and lead to an increase in wild-type protein levels and function. Finally, we show that an increase in RNA stability leading to a higher cytoplasmic localisation underlies these observations. In summary, we demonstrate that TDP-43 nuclear depletion induces a novel category of cryptic RNA processing events and we expand the palette of TDP-43 loss consequences by showing this can also lead to an increase in normal protein translation.
| S-EPMC10836071 | biostudies-literature
Project description:TDP-43 iCLIP of cells transfected with UNC13A minigene
| PRJEB44081 | ENA
Project description:Cytoplasmic aggregation of TDP-43, accompanied by its nuclear clearance, is a key common pathological hallmark of amyotrophic lateral sclerosis and frontotemporal dementia (ALS-FTD). However, a limited understanding of this RNA-binding protein (RBP) impedes the clarification of pathogenic mechanisms underlying TDP-43 proteinopathy. In contrast to RBPs that regulate splicing of conserved exons, we found that TDP-43 repressed the splicing of nonconserved cryptic exons, maintaining intron integrity. When TDP-43 was depleted from mouse embryonic stem cells, these cryptic exons were spliced into messenger RNAs, often disrupting their translation and promoting nonsense-mediated decay. Moreover, enforced repression of cryptic exons prevented cell death in TDP-43-deficient cells. Furthermore, repression of cryptic exons was impaired in ALS-FTD cases, suggesting that this splicing defect could potentially underlie TDP-43 proteinopathy.
| S-EPMC4825810 | biostudies-literature