scholarly journals Retrotransposon Activation Contributes to Neurodegeneration in aDrosophilaTDP-43 Model of ALS

2016 ◽  
Author(s):  
Lisa Krug ◽  
Nabanita Chatterjee ◽  
Rebeca Borges-Monroy ◽  
Stephen Hearn ◽  
Wen-Wei Liao ◽  
...  
Keyword(s):  
Cell Death ◽  
Dna Binding ◽  
Small Interfering Rna ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Endogenous Retrovirus ◽  
Functional Abnormality ◽  
Sporadic Als ◽  
Interfering Rna ◽  
Rna And Dna

ABSTRACTAmyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) are two incurable neurodegenerative disorders that exist on a symptomological spectrum and share both genetic underpinnings and pathophysiological hallmarks. Functional abnormality of TAR DNA-binding protein 43 (TDP-43), an aggregation-prone RNA and DNA binding protein, is observed in the vast majority of both familial and sporadic ALS cases and in ∼40% of FTLD cases, but the cascade of events leading to cell death are not understood. We have expressed human TDP-43 (hTDP-43) inDrosophilaneurons and glia, a model that recapitulates many of the characteristics of TDP-43-linked human disease including protein aggregation pathology, locomotor impairment, and premature death. We report that such expression of hTDP-43 impairs small interfering RNA (siRNA) silencing, which is the major post-transcriptional mechanism of retrotransposable element (RTE) control in somatic tissue. This is accompanied by de-repression of a panel of both LINE and LTR families of RTEs, with somewhat different elements being active in response to hTDP-43 expression in glia versus neurons. hTDP-43 expression in glia causes an early and severe loss of control of a specific RTE, the endogenous retrovirus (ERV)gypsy. We demonstrate thatgypsycauses the degenerative phenotypes in these flies because we are able to rescue the toxicity of glial hTDP-43 either by genetically blocking expression of this RTE or by pharmacologically inhibiting RTE reverse transcriptase activity. Moreover, we provide evidence that activation of DNA damage-mediated programmed cell death underlies both neuronal and glial hTDP-43 toxicity, consistent with RTE-mediated effects in both cell types. Our findings suggest a novel mechanism in which RTE activity contributes to neurodegeneration in TDP-43-mediated diseases such as ALS and FTLD.AUTHOR SUMMARYFunctional abnormality of TAR DNA-binding protein 43 (TDP-43), an aggregation-prone RNA and DNA binding protein, is observed in the vast majority of both familial and sporadic ALS cases and in ∼40% of FTLD cases, and mutations in TDP-43 are causal in a subset of familial ALS cases. Although cytoplasmic inclusions of this mostly nuclear protein are a hallmark of the disease, the cascade of events leading to cell death are not understood. We demonstrate that expression of human TDP-43 (hTDP-43) inDrosophilaneurons or glial cells, which results in toxic cytoplasmic accumulation of TDP-43, causes broad expression of retrotransposons. In the case of glial hTDP-43 expression, the endogenous retrovirus (ERV) gypsy causally contributes to degeneration because inhibiting gypsy genetically or pharmacologically is sufficient to rescue the phenotypic effects. Moreover, we demonstrate that activation of DNA damage-mediated programmed cell death underlies hTDP-43 and gypsy mediated toxicity. Finally, we find that hTDP-43 pathology impairs small interfering RNA silencing, which is an essential system that normally protects the genome from RTEs. These findings suggest a novel mechanism in which a storm of retrotransposon activation drives neurodegeneration in TDP-43 mediated diseases such as ALS and FTLD.

scholarly journals Aggresome Formation and Liquid-liquid Phase Separation Independently Induce Cytoplasmic Aggregation of TAR DNA-binding protein 43

2020 ◽  
Author(s):  
Koji Yamanaka ◽  
Seiji Watanabe ◽  
Hidekazu Inami ◽  
Kotaro Oiwa ◽  
Yuri Murata ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Liquid Phase Separation ◽  
Mammalian Expression ◽  
Sporadic Als ◽  
Aggresome Formation ◽  
Liquid Liquid Phase Separation

Abstract Background Cytoplasmic inclusion of TAR DNA-binding protein 43 (TDP-43) is a pathological hallmark of amyotrophic lateral sclerosis (ALS) and a subtype of frontotemporal lobar degeneration (FTLD). Recent studies have suggested that the formation of cytoplasmic TDP-43 aggregates is dependent on a liquid-liquid phase separation (LLPS) mechanism. However, it is unclear whether TDP-43 pathology is induced through a single intracellular mechanism such as LLPS.Methods We established a TDP-43 aggregation screening system using a cultured neuronal cell line stably expressing EGFP-fused TDP-43 and a mammalian expression library of the inherited ALS/FTLD causative genes. We performed a screening to identify the intracellular mechanisms responsible for TDP-43 aggregation. An immunofluorescence study was conducted using the sporadic ALS spinal cord sections.Results We found that microtubule-related proteins (MRPs) and RNA-binding proteins (RBPs) co-aggregated with TDP-43. MRPs and RBPs sequestered TDP-43 into the cytoplasmic aggregates through distinct mechanisms such as microtubules and LLPS, respectively. The MRPs-induced TDP-43 aggregates were co-localized with aggresomal markers and dependent on histone deacetylase 6 (HDAC6), suggesting that aggresome formation induced the co-aggregation. However, the MRPs-induced aggregates were not affected by 1,6-hexanediol, an LLPS inhibitor. On the other hand, the RBPs-induced TDP-43 aggregates were sensitive to 1,6-hexanediol, but not dependent on microtubules or HDAC6. In sporadic ALS patients, approximately half of skein-like TDP-43 inclusions were co-localized with HDAC6, but round and granular type inclusion were not. Moreover, HDAC6-positive and HDAC6-negative inclusions were found in the same ALS patient, suggesting that the two distinct pathways are both involved in TDP-43 pathology.Conclusion Our findings suggest that at least two distinct pathways (i.e., aggresome formation and LLPS ) are involved in inducing the TDP-43 pathologies.

scholarly journals Aggresome formation and liquid–liquid phase separation independently induce cytoplasmic aggregation of TAR DNA-binding protein 43

2020 ◽  
Vol 11 (10) ◽  
Author(s):  
Seiji Watanabe ◽  
Hidekazu Inami ◽  
Kotaro Oiwa ◽  
Yuri Murata ◽  
Shohei Sakai ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Liquid Phase Separation ◽  
Mammalian Expression ◽  
Sporadic Als ◽  
Aggresome Formation ◽  
Liquid Liquid Phase Separation

Abstract Cytoplasmic inclusion of TAR DNA-binding protein 43 (TDP-43) is a pathological hallmark of amyotrophic lateral sclerosis (ALS) and a subtype of frontotemporal lobar degeneration (FTLD). Recent studies have suggested that the formation of cytoplasmic TDP-43 aggregates is dependent on a liquid–liquid phase separation (LLPS) mechanism. However, it is unclear whether TDP-43 pathology is induced through a single intracellular mechanism such as LLPS. To identify intracellular mechanisms responsible for TDP-43 aggregation, we established a TDP-43 aggregation screening system using a cultured neuronal cell line stably expressing EGFP-fused TDP-43 and a mammalian expression library of the inherited ALS/FTLD causative genes, and performed a screening. We found that microtubule-related proteins (MRPs) and RNA-binding proteins (RBPs) co-aggregated with TDP-43. MRPs and RBPs sequestered TDP-43 into the cytoplasmic aggregates through distinct mechanisms, such as microtubules and LLPS, respectively. The MRPs-induced TDP-43 aggregates were co-localized with aggresomal markers and dependent on histone deacetylase 6 (HDAC6), suggesting that aggresome formation induced the co-aggregation. However, the MRPs-induced aggregates were not affected by 1,6-hexanediol, an LLPS inhibitor. On the other hand, the RBPs-induced TDP-43 aggregates were sensitive to 1,6-hexanediol, but not dependent on microtubules or HDAC6. In sporadic ALS patients, approximately half of skein-like TDP-43 inclusions were co-localized with HDAC6, but round and granular type inclusion were not. Moreover, HDAC6-positive and HDAC6-negative inclusions were found in the same ALS patient, suggesting that the two distinct pathways are both involved in TDP-43 pathology. Our findings suggest that at least two distinct pathways (i.e., aggresome formation and LLPS) are involved in inducing the TDP-43 pathologies.

Energetics of Z-DNA Binding Protein-Mediated Helicity Reversals in DNA, RNA, and DNA–RNA Duplexes

2013 ◽  
Vol 117 (44) ◽  
pp. 13866-13871 ◽  
Author(s):  
Sangsu Bae ◽  
Yuyoung Kim ◽  
Doyoun Kim ◽  
Kyeong Kyu Kim ◽  
Yang-Gyun Kim ◽  
...  
Keyword(s):  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Rna Duplexes ◽  
Z Dna ◽  
Rna And Dna

scholarly journals Neurotoxic 43-kDa TAR DNA-binding Protein (TDP-43) Triggers Mitochondrion-dependent Programmed Cell Death in Yeast

2011 ◽  
Vol 286 (22) ◽  
pp. 19958-19972 ◽  
Author(s):  
Ralf J. Braun ◽  
Cornelia Sommer ◽  
Didac Carmona-Gutierrez ◽  
Chamel M. Khoury ◽  
Julia Ring ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Dna Binding ◽  
Molecular Mechanisms ◽  
Binding Protein ◽  
Cell Loss ◽  
Dna Binding Protein ◽  
Respiratory Capacity ◽  
Endonuclease G ◽  
Markers Of Oxidative Stress

Pathological neuronal inclusions of the 43-kDa TAR DNA-binding protein (TDP-43) are implicated in dementia and motor neuron disorders; however, the molecular mechanisms of the underlying cell loss remain poorly understood. Here we used a yeast model to elucidate cell death mechanisms upon expression of human TDP-43. TDP-43-expressing cells displayed markedly increased markers of oxidative stress, apoptosis, and necrosis. Cytotoxicity was dose- and age-dependent and was potentiated upon expression of disease-associated variants. TDP-43 was localized in perimitochondrial aggregate-like foci, which correlated with cytotoxicity. Although the deleterious effects of TDP-43 were significantly decreased in cells lacking functional mitochondria, cell death depended neither on the mitochondrial cell death proteins apoptosis-inducing factor, endonuclease G, and cytochrome c nor on the activity of cell death proteases like the yeast caspase 1. In contrast, impairment of the respiratory chain attenuated the lethality upon TDP-43 expression with a stringent correlation between cytotoxicity and the degree of respiratory capacity or mitochondrial DNA stability. Consistently, an increase in the respiratory capacity of yeast resulted in enhanced TDP-43-triggered cytotoxicity, oxidative stress, and cell death markers. These data demonstrate that mitochondria and oxidative stress are important to TDP-43-triggered cell death in yeast and may suggest a similar role in human TDP-43 pathologies.

scholarly journals A member of the Whirly family is a multifunctional RNA- and DNA-binding protein that is essential for chloroplast biogenesis

2008 ◽  
Vol 36 (16) ◽  
pp. 5152-5165 ◽  
Author(s):  
J. Prikryl ◽  
K. P. Watkins ◽  
G. Friso ◽  
K. J. van Wijk ◽  
A. Barkan
Keyword(s):  
Dna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Chloroplast Biogenesis ◽  
Rna And Dna

scholarly journals Transforming Growth Factor-β-Activated Protein Kinase 1-Binding Protein (TΑΒ)-1α, But Not ΤΑΒ1β, Mediates Cytokine-Induced p38 Mitogen-Activated Protein Kinase Phosphorylation and Cell Death in Insulin-Producing Cells

Endocrinology ◽  
2007 ◽  
Vol 149 (1) ◽  
pp. 302-309 ◽  
Author(s):  
Natalia Makeeva ◽  
Godfried M. Roomans ◽  
Jason W. Myers ◽  
Nils Welsh
Keyword(s):  
Cell Death ◽  
Protein Kinase ◽  
Small Interfering Rna ◽  
Transforming Growth Factor ◽  
Islet Cells ◽  
Binding Protein ◽  
Mitogen Activated Protein Kinase ◽  
Β Cell ◽  
Insulin Producing Cells ◽  
Interfering Rna

Previous studies have indicated that the p38 MAPK participates in signaling events that lead to the death of the insulin-producing β-cell. The aim of the present study was to elucidate the role of the TGF-β-activated protein kinase 1-binding protein 1 (TAB1) in the cytokine-induced activation of p38. Levels of TAB1 mRNA and protein were analyzed by real-time PCR and immunoblotting, and TAB1 expression in mouse and human islet cells was down-regulated using lipofection of diced-small interfering RNA. TAB1 overexpression in β-TC6 cells was achieved by transient transfections followed by fluorescence activated cell sorting. Phosphorylation of p38, c-Jun N-terminal kinase, and ERK was assessed by immunoblotting, and viability was determined using vital staining with bisbenzimide and propidium iodide. We observed that TAB1 is expressed in insulin-producing cells. Cytokine (IL-1β + interferon-γ)-stimulated p38 phosphorylation was significantly increased by ΤΑΒ1α overexpression, but not ΤΑΒ1β overexpression, in β-TC6 cells. The ΤΑΒ1α-augmented p38 phosphorylation was paralleled by an increased cell death rate. Treatment of islet cells with diced-small interfering RNA specific for TAB1, but not for TGF-β-activated kinase 1, resulted in lowered cytokine-induced p38 phosphorylation and protection against cell death. The cytokine-induced phosphorylation of c-Jun N-terminal kinase and ERK was not affected by changes in TAB1 levels. Finally, TAB1 phosphorylation was decreased by the p38 inhibitor SB203580. We conclude that ΤΑΒ1α, but not ΤΑΒ1β, plays an important role in the activation of p38 in insulin-producing cells and therefore also in cytokine-induced β-cell death.

The DNA-binding protein YB-1 is a direct MYCN target and influences repair and resistance in neuroblastoma cell lines

2010 ◽  
Vol 222 (03) ◽  
Author(s):  
S Degen ◽  
S Kuhfittig-Kulle ◽  
JH Schulte ◽  
F Westermann ◽  
A Schramm ◽  
...  
Keyword(s):  
Dna Binding ◽  
Cell Lines ◽  
Binding Protein ◽  
Neuroblastoma Cell ◽  
Dna Binding Protein ◽  
Neuroblastoma Cell Lines
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