A
            <i>Drosophila</i>
            model for TDP-43 proteinopathy

Li, Yan; Ray, Payal; Rao, Elizabeth J.; Shi, Chen; Guo, Weirui; Chen, Xiaoping; Woodruff, Elvin; Fushimi, Kazuo; Wu, Jane Y.

doi:10.1073/pnas.0913602107

Cited by 249 publications

(252 citation statements)

References 33 publications

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“…Furthermore, the expression of a CTF in the fly eye fails to induce neurodegeneration 12 . This evidence indicates that the regulation of the total amount of full-length TDP-43, rather than that of the CTFs, is a critical determinant of cell survival.…”

Section: Discussionmentioning

confidence: 99%

“…The following primary antibodies were used: antiHaloTag polyclonal antibody (pAb; 1:500, G928A, Promega), anti-SNAP-tag pAb (1:1,000, P9310S, NEB), anti-GAPDH mAb (1:50,000, M171-3, MBL), anti-TARDBP pAb (1:2,500, 10782-2-AP, ProteinTech), anti-TARDBP pAb for C terminus region (1:500, NB110-55376, NOVUS Biologicals), anti-TDP-43 N terminus (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) To analyse the effect of each reagent, the cells were cultured in the presence of each reagent (caspase-4 inhibitor (50 mM), caspase-3/7 inhibitor (50 mM), NecroX-2 (20 mM), Necrostatin-1 (50 mM) and Dantrolene (30 mM)), and the medium that contained the reagent was replaced every 24 h (refs 15,40).…”

Section: Methodsmentioning

confidence: 99%

“…Transgenic mice expressing wild-type human TDP-43 also develop an ALS-like phenotype in a TDP-43 dosedependent manner 11 . Finally, the expression of full-length wildtype human TDP-43 in the eyes of Drosophila leads to neurodegeneration, but a mutant that comprises only the C-terminal region from a.a. 202 does not have this effect 12 . The evidence listed above indicates that the increased expression of full-length TDP-43 is deleterious for neuronal survival.…”

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confidence: 99%

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The cleavage pattern of TDP-43 determines its rate of clearance and cytotoxicity

et al. 2015

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TAR DNA-binding protein of 43 kDa (TDP-43) and its C-terminal fragment of 25 kDa (CTF25) play critical roles in amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Although the overexpression of TDP-43 in cultured cells and animals results in the production of CTF25, the cleavage site that generates CTF25 and biological significance of the cleavage remain undetermined. Here we identify Asp174 as a cleavage site for CTF25. TDP-43 is cleaved initially after Asp174, which activates caspase-3/7 to accelerate TDP-43 fragmentation. Consequently, blockage of this cleavage results in a severe delay in TDP-43 clearance and prolonged necrotic cell death. We further show that the endoplasmic reticulum membrane-bound caspase-4 is the enzyme responsible for the cleavage after Asp174 and inhibition of caspase-4 activity slows TDP-43 fragmentation and reduces cell viability. These findings suggest that caspase-4-mediated cleavage after Asp174 is an initiator of TDP-43 clearance, which is required to avoid cell death induced by overexpressed TDP-43. A myotrophic lateral sclerosis (ALS) is one of the most devastating neurodegenerative diseases and is characterized by muscle weakness due to the degeneration of both upper and lower motor neurons. Although the pathogenic mechanism of ALS remains unresolved, the RNA-binding protein TDP-43 has been shown to accumulate in cytoplasmic inclusions in the affected regions of the spinal cord and brain in patients with ALS and frontotemporal lobar degeneration (FTLD), respectively 1,2 . Subsequently, mutations linked with ALS and FTLD have been identified in the gene that encodes TDP-43, which has confirmed the significance of TDP-43 in the pathogenesis of these diseases 3,4 . Most of these mutations occur within or near the carboxyl-terminal (C-terminal) glycine-rich domain (GRD) of TDP-43, except for the D169G point mutation that resides in RNA recognition motif 1 (refs 3,4). TDP-43 is normally localized predominantly in the nucleus. However, in ALS and FTLD patients with TDP-43-positive cytoplasmic inclusions, the protein is abnormally phosphorylated, ubiquitinated and truncated. This results in the accumulation of an B25-kDa C-terminal fragment (CTF25), in addition to other minor CTFs and the full-length TDP-43, in cytoplasmic aggregates. CTFs are hallmarks of forms of disease whose pathology is associated exclusively with abnormalities in TDP-43 and are observed in patients with not only ALS and FTLD but also Alzheimer's disease 5 . Amino-terminal (N-terminal) analysis of CTFs obtained from brain autopsies of patients with FTLD has resulted in the identification of three cleavage sites, Arg208, Asp219 and Asp247, which give rise to CTFs 6,7 . However, the expected sizes of the resulting CTFs are less than 25 kDa, which suggests that CTF25 is probably cleaved at a different position.TDP-43 is a widely expressed 414-amino acid (a.a.) protein comprised of two RNA recognition motifs (RRM1 at a.a. 106-176 and RRM2 at a.a. 191-262) and the GRD 8,9 . The chronic stabilization...

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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The cleavage pattern of TDP-43 determines its rate of clearance and cytotoxicity

et al. 2015

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“…Moreover, because increased expression of TDP-43 is also toxic to motor neurons (12,13), it will be also important to identify a set of downstream targets of TDP-43 to facilitate our understanding of pathways that may be impacted by TDP-43. Interestingly, a recent RNAi knockdown study revealed histone deacetylase 6 (HDAC6) as a target of TDP-43 in cultured cells (14).…”

mentioning

confidence: 99%

Deletion of TDP-43 down-regulates Tbc1d1 , a gene linked to obesity, and alters body fat metabolism

Chiang

Ling

Jeong

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

265

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Tat activating regulatory DNA-binding protein (Tardbp or TDP-43), a highly conserved metazoan DNA/RNA binding protein thought to be involved in RNA transcription and splicing, has been linked to the pathophysiology of amyotrophic lateral sclerosis and frontotemporal lobar degeneration and is essential for early embryonic development. However, neither the physiological role of TDP-43 in the adult nor its downstream targets are well defined. To address these questions, we developed conditional Tardbp-KO mice and embryonic stem (ES) cell models. Here, we show that postnatal deletion of Tardbp in mice caused dramatic loss of body fat followed by rapid death. Moreover, conditional Tardbp-KO ES cells failed to proliferate. Importantly, high-throughput DNA sequencing analysis on the transcriptome of ES cells lacking Tardbp revealed a set of downstream targets of TDP-43. We show that Tbc1d1, a gene known to mediate leanness and linked to obesity, is down-regulated in the absence of TDP-43. Collectively, our results establish that TDP-43 is critical for fat metabolism and ES cell survival.conditional knockout mice | amyotrophic lateral sclerosis | frontotemporal dementia | energy metabolism | RNA-sequencing I dentified initially as a cellular protein that regulates human immunodeficiency viral gene transcription (1), Tat activating regulatory DNA-binding protein (Tardbp or TDP-43) is a highly conserved DNA/RNA-binding protein thought to regulate alternative splicing of cystic fibrosis transmembrane conductance regulator (CFTR) and survival of motor neuron (SMN) through binding to heterogeneous nuclear ribonucleoprotein or (UG) n repeats of these target transcripts (2-4). Biophysical studies indicate that TDP-43 forms a dimer harboring two RNA-binding domains that preferentially bind to TG/UG repeats (5). Whereas TDP-43 is normally localized to the nucleus, it is redistributed as insoluble aggregates in neuronal nuclei, perikarya and neurites in amyotrophic lateral sclerosis (ALS) (6, 7) and frontotemporal lobar degeneration (FTLD) (8). The identification of missense mutations in TARDBP in familial and sporadic ALS (9, 10) supports the idea that this nuclear protein plays a critical role in the pathogenesis of these neurodegenerative disorders. Interestingly, most of these mutations identified to date are localized to the Cterminal domain of TDP-43, a heterogeneous nuclear ribonucleoprotein-interacting region that may be critical for the normal function of the protein. Although mutant TDP-43 mice showed evidence of neurodegeneration, no TDP-43-positive cytoplasmic aggregates were observed in neurons of these mutant mice, suggesting that altered RNA metabolism rather than TDP-43 aggregates underlies the pathogenesis of ALS or FTLD (11).To begin clarifying the molecular basis of mutant TDP-43-linked disease, it will be crucial to understand the physiological and cellular functions of TDP-43. Moreover, because increased expression of TDP-43 is also toxic to motor neurons (12, 13), it will be also important to identify a set ...

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“…In Drosophila, at least three different fly models elucidated the role of TBPH in neuronal and neuromuscular development. Indeed, flies mutants for TBPH closely reproduce most of the phenotypes observed in ALS patients like decreasing viability, affected synaptic transmission, defective locomotion and also age-related progressive neurodegeneration (Ritson et al 2010;Hazelett et al 2012;Li et al 2010;Neumann et al 2006). Recently, it has emerged that TBPH interacts with the Futsch protein, the Drosophila homolog to human MAP1B (Godena et al 2011) (Fig.…”

Section: Roles In Neuromuscular Developmentmentioning

confidence: 99%

Emerging Roles for hnRNPs in post-transcriptional regulation: what can we learn from flies?

2014

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Heterogeneous nuclear ribonucleoproteins (hnRNPs) are a highly conserved family of RNA-binding proteins able to associate with nascent RNAs in order to support their localization, maturation and translation. Research over this last decade has remarked the importance of gene regulatory processes at post-transcriptional level, highlighting the emerging roles of hnRNPs in several essential biological events. Indeed, hnRNPs are key factors in regulating gene expression, thus, having a number of roles in many biological pathways. Moreover, failure of the activities catalysed by hnRNPs affects various biological processes and may underlie several human diseases including cancer, diabetes and neurodegenerative syndromes. In this review, we summarize some of hnRNPs' roles in the model organism Drosophila melanogaster, particularly focusing on their participation in all aspects of post-transcriptional regulation as well as their conserved role and involvement in the aetiology of human pathologies.

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A Drosophila model for TDP-43 proteinopathy

Cited by 249 publications

References 33 publications

The cleavage pattern of TDP-43 determines its rate of clearance and cytotoxicity

The cleavage pattern of TDP-43 determines its rate of clearance and cytotoxicity

Deletion of TDP-43 down-regulates Tbc1d1 , a gene linked to obesity, and alters body fat metabolism

Emerging Roles for hnRNPs in post-transcriptional regulation: what can we learn from flies?

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