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1.
Acta Neuropathol ; 147(1): 50, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38443601

RESUMO

TDP-43 is an aggregation-prone protein which accumulates in the hallmark pathological inclusions of amyotrophic lateral sclerosis (ALS). However, the analysis of deeply phenotyped human post-mortem samples has shown that TDP-43 aggregation, revealed by standard antibody methods, correlates poorly with symptom manifestation. Recent identification of cryptic-splicing events, such as the detection of Stathmin-2 (STMN-2) cryptic exons, are providing evidence implicating TDP-43 loss-of-function as a potential driving pathomechanism but the temporal nature of TDP-43 loss and its relation to the disease process and clinical phenotype is not known. To address these outstanding questions, we used a novel RNA aptamer, TDP-43APT, to detect TDP-43 pathology and used single molecule in situ hybridization to sensitively reveal TDP-43 loss-of-function and applied these in a deeply phenotyped human post-mortem tissue cohort. We demonstrate that TDP-43APT identifies pathological TDP-43, detecting aggregation events that cannot be detected by classical antibody stains. We show that nuclear TDP-43 pathology is an early event, occurring prior to cytoplasmic accumulation and is associated with loss-of-function measured by coincident STMN-2 cryptic splicing pathology. Crucially, we show that these pathological features of TDP-43 loss-of-function precede the clinical inflection point and are not required for region specific clinical manifestation. Furthermore, we demonstrate that gain-of-function in the form of extensive cytoplasmic accumulation, but not loss-of-function, is the primary molecular correlate of clinical manifestation. Taken together, our findings demonstrate implications for early diagnostics as the presence of STMN-2 cryptic exons and early TDP-43 aggregation events could be detected prior to symptom onset, holding promise for early intervention in ALS.


Assuntos
Esclerose Lateral Amiotrófica , Aptâmeros de Nucleotídeos , Humanos , Esclerose Lateral Amiotrófica/genética , Proteínas de Ligação a DNA/genética , Splicing de RNA , Anticorpos
2.
bioRxiv ; 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38313254

RESUMO

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.

3.
Sci Transl Med ; 16(734): eadg7162, 2024 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-38277467

RESUMO

Functional loss of TDP-43, an RNA binding protein genetically and pathologically linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), leads to the inclusion of cryptic exons in hundreds of transcripts during disease. Cryptic exons can promote the degradation of affected transcripts, deleteriously altering cellular function through loss-of-function mechanisms. Here, we show that mRNA transcripts harboring cryptic exons generated de novo proteins in TDP-43-depleted human iPSC-derived neurons in vitro, and de novo peptides were found in cerebrospinal fluid (CSF) samples from patients with ALS or FTD. Using coordinated transcriptomic and proteomic studies of TDP-43-depleted human iPSC-derived neurons, we identified 65 peptides that mapped to 12 cryptic exons. Cryptic exons identified in TDP-43-depleted human iPSC-derived neurons were predictive of cryptic exons expressed in postmortem brain tissue from patients with TDP-43 proteinopathy. These cryptic exons produced transcript variants that generated de novo proteins. We found that the inclusion of cryptic peptide sequences in proteins altered their interactions with other proteins, thereby likely altering their function. Last, we showed that 18 de novo peptides across 13 genes were present in CSF samples from patients with ALS/FTD spectrum disorders. The demonstration of cryptic exon translation suggests new mechanisms for ALS/FTD pathophysiology downstream of TDP-43 dysfunction and may provide a potential strategy to assay TDP-43 function in patient CSF.


Assuntos
Esclerose Lateral Amiotrófica , Demência Frontotemporal , Humanos , Esclerose Lateral Amiotrófica/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Demência Frontotemporal/genética , Peptídeos , Proteômica
4.
bioRxiv ; 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-38014203

RESUMO

A system enabling the expression of therapeutic proteins specifically in diseased cells would be transformative, providing greatly increased safety and the possibility of pre-emptive treatment. Here we describe "TDP-REG", a precision medicine approach primarily for amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), which exploits the cryptic splicing events that occur in cells with TDP-43 loss-of-function (TDP-LOF) in order to drive expression specifically in diseased cells. In addition to modifying existing cryptic exons for this purpose, we develop a deep-learning-powered algorithm for generating customisable cryptic splicing events, which can be embedded within virtually any coding sequence. By placing part of a coding sequence within a novel cryptic exon, we tightly couple protein expression to TDP-LOF. Protein expression is activated by TDP-LOF in vitro and in vivo, including TDP-LOF induced by cytoplasmic TDP-43 aggregation. In addition to generating a variety of fluorescent and luminescent reporters, we use this system to perform TDP-LOF-dependent genomic prime editing to ablate the UNC13A cryptic donor splice site. Furthermore, we design a panel of tightly gated, autoregulating vectors encoding a TDP-43/Raver1 fusion protein, which rescue key pathological cryptic splicing events. In summary, we combine deep-learning and rational design to create sophisticated splicing sensors, resulting in a platform that provides far safer therapeutics for neurodegeneration, potentially even enabling preemptive treatment of at-risk individuals.

5.
Mol Neurodegener ; 18(1): 16, 2023 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-36922834

RESUMO

TDP-43 is an RNA-binding protein with a crucial nuclear role in splicing, and mislocalises from the nucleus to the cytoplasm in a range of neurodegenerative disorders. TDP-43 proteinopathy spans a spectrum of incurable, heterogeneous, and increasingly prevalent neurodegenerative diseases, including the amyotrophic lateral sclerosis and frontotemporal dementia disease spectrum and a significant fraction of Alzheimer's disease. There are currently no directed disease-modifying therapies for TDP-43 proteinopathies, and no way to distinguish who is affected before death. It is now clear that TDP-43 proteinopathy leads to a number of molecular changes, including the de-repression and inclusion of cryptic exons. Importantly, some of these cryptic exons lead to the loss of crucial neuronal proteins and have been shown to be key pathogenic players in disease pathogenesis (e.g., STMN2), as well as being able to modify disease progression (e.g., UNC13A). Thus, these aberrant splicing events make promising novel therapeutic targets to restore functional gene expression. Moreover, presence of these cryptic exons is highly specific to patients and areas of the brain affected by TDP-43 proteinopathy, offering the potential to develop biomarkers for early detection and stratification of patients. In summary, the discovery of cryptic exons gives hope for novel diagnostics and therapeutics on the horizon for TDP-43 proteinopathies.


Assuntos
Esclerose Lateral Amiotrófica , Demência Frontotemporal , Doenças Neurodegenerativas , Proteinopatias TDP-43 , Humanos , Demência Frontotemporal/metabolismo , Esclerose Lateral Amiotrófica/metabolismo , Proteinopatias TDP-43/metabolismo , Neurônios/metabolismo , Éxons/genética , Doenças Neurodegenerativas/metabolismo
6.
Brain ; 146(7): 2723-2729, 2023 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-36797998

RESUMO

CAG repeat expansions in exon 1 of the AR gene on the X chromosome cause spinal and bulbar muscular atrophy, a male-specific progressive neuromuscular disorder associated with a variety of extra-neurological symptoms. The disease has a reported male prevalence of approximately 1:30 000 or less, but the AR repeat expansion frequency is unknown. We established a pipeline, which combines the use of the ExpansionHunter tool and visual validation, to detect AR CAG expansion on whole-genome sequencing data, benchmarked it to fragment PCR sizing, and applied it to 74 277 unrelated individuals from four large cohorts. Our pipeline showed sensitivity of 100% [95% confidence interval (CI) 90.8-100%], specificity of 99% (95% CI 94.2-99.7%), and a positive predictive value of 97.4% (95% CI 84.4-99.6%). We found the mutation frequency to be 1:3182 (95% CI 1:2309-1:4386, n = 117 734) X chromosomes-10 times more frequent than the reported disease prevalence. Modelling using the novel mutation frequency led to estimate disease prevalence of 1:6887 males, more than four times more frequent than the reported disease prevalence. This discrepancy is possibly due to underdiagnosis of this neuromuscular condition, reduced penetrance, and/or pleomorphic clinical manifestations.


Assuntos
Atrofia Muscular Espinal , Receptores Androgênicos , Humanos , Masculino , Receptores Androgênicos/genética , Atrofia Muscular Espinal/genética , Atrofia Muscular , Reação em Cadeia da Polimerase , Expansão das Repetições de Trinucleotídeos/genética
7.
bioRxiv ; 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36747793

RESUMO

Functional loss of TDP-43, an RNA-binding protein genetically and pathologically linked to ALS and FTD, leads to inclusion of cryptic exons in hundreds of transcripts during disease. Cryptic exons can promote degradation of affected transcripts, deleteriously altering cellular function through loss-of-function mechanisms. However, the possibility of de novo protein synthesis from cryptic exon transcripts has not been explored. Here, we show that mRNA transcripts harboring cryptic exons generate de novo proteins both in TDP-43 deficient cellular models and in disease. Using coordinated transcriptomic and proteomic studies of TDP-43 depleted iPSC-derived neurons, we identified numerous peptides that mapped to cryptic exons. Cryptic exons identified in iPSC models were highly predictive of cryptic exons expressed in brains of patients with TDP-43 proteinopathy, including cryptic transcripts that generated de novo proteins. We discovered that inclusion of cryptic peptide sequences in proteins altered their interactions with other proteins, thereby likely altering their function. Finally, we showed that these de novo peptides were present in CSF from patients with ALS. The demonstration of cryptic exon translation suggests new mechanisms for ALS pathophysiology downstream of TDP-43 dysfunction and may provide a strategy for novel biomarker development.

8.
Brain Commun ; 4(5): fcac242, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36267332

RESUMO

Many lines of evidence have highlighted the role played by heterogeneous nuclear ribonucleoproteins in amyotrophic lateral sclerosis. In this study, we have aimed to identify transcripts co-regulated by TAR DNA-binding protein 43 kDa and highly conserved heterogeneous nuclear ribonucleoproteins which have been previously shown to regulate TAR DNA-binding protein 43 kDa toxicity (deleted in azoospermia-associated protein 1, heterogeneous nuclear ribonucleoprotein -Q, -D, -K and -U). Using the transcriptome analyses, we have uncovered that Nitric Oxide Synthase 1 Adaptor Protein mRNA is a direct TAR DNA-binding protein 43 kDa target, and in flies, its modulation alone can rescue TAR DNA-binding protein 43 kDa pathology. In primary mouse cortical neurons, we show that TAR DNA-binding protein 43 kDa mediated downregulation of Nitric Oxide Synthase 1 Adaptor Protein expression strongly affects the NMDA-receptor signalling pathway. In human patients, the downregulation of Nitric Oxide Synthase 1 Adaptor Protein mRNA strongly correlates with TAR DNA-binding protein 43 kDa proteinopathy as measured by cryptic Stathmin-2 and Unc-13 homolog A cryptic exon inclusion. Overall, our results demonstrate that Nitric Oxide Synthase 1 Adaptor Protein may represent a novel disease-relevant gene, potentially suitable for the development of new therapeutic strategies.

9.
Commun Biol ; 5(1): 314, 2022 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-35383280

RESUMO

TDP-43 (TAR DNA-binding protein 43) aggregation and redistribution are recognised as a hallmark of amyotrophic lateral sclerosis and frontotemporal dementia. As TDP-43 inclusions have recently been described in the muscle of inclusion body myositis patients, this highlights the need to understand the role of TDP-43 beyond the central nervous system. Using RNA-seq, we directly compare TDP-43-mediated RNA processing in muscle (C2C12) and neuronal (NSC34) mouse cells. TDP-43 displays a cell-type-characteristic behaviour targeting unique transcripts in each cell-type, which is due to characteristic expression of RNA-binding proteins, that influence TDP-43's performance and define cell-type specific splicing. Among splicing events commonly dysregulated in both cell lines, we identify some that are TDP-43-dependent also in human cells. Inclusion levels of these alternative exons are altered in tissues of patients suffering from FTLD and IBM. We therefore propose that TDP-43 dysfunction contributes to disease development either in a common or a tissue-specific manner.


Assuntos
Esclerose Lateral Amiotrófica , Demência Frontotemporal , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/metabolismo , Animais , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Demência Frontotemporal/genética , Humanos , Camundongos , Músculos/metabolismo , Splicing de RNA
10.
Nature ; 603(7899): 131-137, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35197628

RESUMO

Variants of UNC13A, a critical gene for synapse function, increase the risk of amyotrophic lateral sclerosis and frontotemporal dementia1-3, two related neurodegenerative diseases defined by mislocalization of the RNA-binding protein TDP-434,5. Here we show that TDP-43 depletion induces robust inclusion of a cryptic exon in UNC13A, resulting in nonsense-mediated decay and loss of UNC13A protein. Two common intronic UNC13A polymorphisms strongly associated with amyotrophic lateral sclerosis and frontotemporal dementia risk overlap with TDP-43 binding sites. These polymorphisms potentiate cryptic exon inclusion, both in cultured cells and in brains and spinal cords from patients with these conditions. Our findings, which demonstrate a genetic link between loss of nuclear TDP-43 function and disease, reveal the mechanism by which UNC13A variants exacerbate the effects of decreased TDP-43 function. They further provide a promising therapeutic target for TDP-43 proteinopathies.


Assuntos
Esclerose Lateral Amiotrófica , Demência Frontotemporal , Proteinopatias TDP-43 , Processamento Alternativo , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/metabolismo , Códon sem Sentido , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Demência Frontotemporal/genética , Demência Frontotemporal/metabolismo , Humanos , Proteínas do Tecido Nervoso , Polimorfismo de Nucleotídeo Único/genética
11.
Acta Neuropathol ; 142(4): 609-627, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34274995

RESUMO

Heterogeneous nuclear ribonucleoproteins (HnRNPs) are a group of ubiquitously expressed RNA-binding proteins implicated in the regulation of all aspects of nucleic acid metabolism. HnRNP K is a member of this highly versatile hnRNP family. Pathological redistribution of hnRNP K to the cytoplasm has been linked to the pathogenesis of several malignancies but, until now, has been underexplored in the context of neurodegenerative disease. Here we show hnRNP K mislocalisation in pyramidal neurons of the frontal cortex to be a novel neuropathological feature that is associated with both frontotemporal lobar degeneration and ageing. HnRNP K mislocalisation is mutually exclusive to TDP-43 and tau pathological inclusions in neurons and was not observed to colocalise with mitochondrial, autophagosomal or stress granule markers. De-repression of cryptic exons in RNA targets following TDP-43 nuclear depletion is an emerging mechanism of potential neurotoxicity in frontotemporal lobar degeneration and the mechanistically overlapping disorder amyotrophic lateral sclerosis. We silenced hnRNP K in neuronal cells to identify the transcriptomic consequences of hnRNP K nuclear depletion. Intriguingly, by performing RNA-seq analysis we find that depletion of hnRNP K induces 101 novel cryptic exon events. We validated cryptic exon inclusion in an SH-SY5Y hnRNP K knockdown and in FTLD brain exhibiting hnRNP K nuclear depletion. We, therefore, present evidence for hnRNP K mislocalisation to be associated with FTLD and for this to induce widespread changes in splicing.


Assuntos
Envelhecimento/metabolismo , Envelhecimento/patologia , Degeneração Lobar Frontotemporal/metabolismo , Degeneração Lobar Frontotemporal/patologia , Ribonucleoproteínas Nucleares Heterogêneas Grupo K/metabolismo , Splicing de RNA/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/genética , Estudos de Casos e Controles , Feminino , Degeneração Lobar Frontotemporal/genética , Humanos , Masculino , Pessoa de Meia-Idade
12.
Nat Commun ; 12(1): 3880, 2021 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-34162872

RESUMO

Immune checkpoint blockade (ICB) benefits only a small subset of patients with small cell lung cancer (SCLC), yet the mechanisms driving benefit are poorly understood. To identify predictors of clinical benefit to ICB, we performed immunogenomic profiling of tumor samples from patients with relapsed SCLC. Tumors of patients who derive clinical benefit from ICB exhibit cytotoxic T-cell infiltration, high expression of antigen processing and presentation machinery (APM) genes, and low neuroendocrine (NE) differentiation. However, elevated Notch signaling, which positively correlates with low NE differentiation, most significantly predicts clinical benefit to ICB. Activation of Notch signaling in a NE human SCLC cell line induces a low NE phenotype, marked by increased expression of APM genes, demonstrating a mechanistic link between Notch activation, low NE differentiation and increased intrinsic tumor immunity. Our findings suggest Notch signaling as a determinant of response to ICB in SCLC.


Assuntos
Inibidores de Checkpoint Imunológico/uso terapêutico , Neoplasias Pulmonares/tratamento farmacológico , Receptor Notch1/genética , Transdução de Sinais/genética , Carcinoma de Pequenas Células do Pulmão/tratamento farmacológico , Antineoplásicos Imunológicos/uso terapêutico , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Linhagem Celular Tumoral , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Recidiva Local de Neoplasia , Receptor Notch1/metabolismo , Carcinoma de Pequenas Células do Pulmão/genética , Carcinoma de Pequenas Células do Pulmão/patologia , Resultado do Tratamento , Sequenciamento do Exoma/métodos
13.
J Neurosci ; 41(6): 1301-1316, 2021 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-33303679

RESUMO

Spatial selective listening and auditory choice underlie important processes including attending to a speaker at a cocktail party and knowing how (or whether) to respond. To examine task encoding and the relative timing of potential neural substrates underlying these behaviors, we developed a spatial selective detection paradigm for monkeys, and recorded activity in primary auditory cortex (AC), dorsolateral prefrontal cortex (dlPFC), and the basolateral amygdala (BLA). A comparison of neural responses among these three areas showed that, as expected, AC encoded the side of the cue and target characteristics before dlPFC and BLA. Interestingly, AC also encoded the choice of the monkey before dlPFC and around the time of BLA. Generally, BLA showed weak responses to all task features except the choice. Decoding analyses suggested that errors followed from a failure to encode the target stimulus in both AC and dlPFC, but again, these differences arose earlier in AC. The similarities between AC and dlPFC responses were abolished during passive sensory stimulation with identical trial conditions, suggesting that the robust sensory encoding in dlPFC is contextually gated. Thus, counter to a strictly PFC-driven decision process, in this spatial selective listening task AC neural activity represents the sensory and decision information before dlPFC. Unlike in the visual domain, in this auditory task, the BLA does not appear to be robustly involved in selective spatial processing.SIGNIFICANCE STATEMENT We examined neural correlates of an auditory spatial selective listening task by recording single-neuron activity in behaving monkeys from the amygdala, dorsolateral prefrontal cortex, and auditory cortex. We found that auditory cortex coded spatial cues and choice-related activity before dorsolateral prefrontal cortex or the amygdala. Auditory cortex also had robust delay period activity. Therefore, we found that auditory cortex could support the neural computations that underlie the behavioral processes in the task.


Assuntos
Córtex Auditivo/fisiologia , Percepção Auditiva/fisiologia , Complexo Nuclear Basolateral da Amígdala/fisiologia , Tomada de Decisões/fisiologia , Desempenho Psicomotor/fisiologia , Estimulação Acústica/métodos , Animais , Córtex Auditivo/diagnóstico por imagem , Complexo Nuclear Basolateral da Amígdala/diagnóstico por imagem , Macaca mulatta , Masculino , Estimulação Luminosa/métodos , Córtex Pré-Frontal/diagnóstico por imagem , Córtex Pré-Frontal/fisiologia
14.
J Clin Invest ; 130(11): 6080-6092, 2020 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-32790644

RESUMO

No treatment for frontotemporal dementia (FTD), the second most common type of early-onset dementia, is available, but therapeutics are being investigated to target the 2 main proteins associated with FTD pathological subtypes: TDP-43 (FTLD-TDP) and tau (FTLD-tau). Testing potential therapies in clinical trials is hampered by our inability to distinguish between patients with FTLD-TDP and FTLD-tau. Therefore, we evaluated truncated stathmin-2 (STMN2) as a proxy of TDP-43 pathology, given the reports that TDP-43 dysfunction causes truncated STMN2 accumulation. Truncated STMN2 accumulated in human induced pluripotent stem cell-derived neurons depleted of TDP-43, but not in those with pathogenic TARDBP mutations in the absence of TDP-43 aggregation or loss of nuclear protein. In RNA-Seq analyses of human brain samples from the NYGC ALS cohort, truncated STMN2 RNA was confined to tissues and disease subtypes marked by TDP-43 inclusions. Last, we validated that truncated STMN2 RNA was elevated in the frontal cortex of a cohort of patients with FTLD-TDP but not in controls or patients with progressive supranuclear palsy, a type of FTLD-tau. Further, in patients with FTLD-TDP, we observed significant associations of truncated STMN2 RNA with phosphorylated TDP-43 levels and an earlier age of disease onset. Overall, our data uncovered truncated STMN2 as a marker for TDP-43 dysfunction in FTD.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Lobo Frontal/metabolismo , Demência Frontotemporal/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Estatmina/metabolismo , Biomarcadores/metabolismo , Proteínas de Ligação a DNA/genética , Feminino , Lobo Frontal/patologia , Demência Frontotemporal/genética , Demência Frontotemporal/patologia , Humanos , Células-Tronco Pluripotentes Induzidas/patologia , Masculino , Pessoa de Meia-Idade , Mutação , Estatmina/genética
15.
Nucleic Acids Res ; 48(12): 6889-6905, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32479602

RESUMO

Mutations in the RNA-binding protein FUS cause amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disease. FUS plays a role in numerous aspects of RNA metabolism, including mRNA splicing. However, the impact of ALS-causative mutations on splicing has not been fully characterized, as most disease models have been based on overexpressing mutant FUS, which will alter RNA processing due to FUS autoregulation. We and others have recently created knockin models that overcome the overexpression problem, and have generated high depth RNA-sequencing on FUS mutants in parallel to FUS knockout, allowing us to compare mutation-induced changes to genuine loss of function. We find that FUS-ALS mutations induce a widespread loss of function on expression and splicing. Specifically, we find that mutant FUS directly alters intron retention levels in RNA-binding proteins. Moreover, we identify an intron retention event in FUS itself that is associated with its autoregulation. Altered FUS levels have been linked to disease, and we show here that this novel autoregulation mechanism is altered by FUS mutations. Crucially, we also observe this phenomenon in other genetic forms of ALS, including those caused by TDP-43, VCP and SOD1 mutations, supporting the concept that multiple ALS genes interact in a regulatory network.


Assuntos
Esclerose Lateral Amiotrófica/genética , Homeostase/genética , Proteína FUS de Ligação a RNA/genética , Animais , Citoplasma/genética , Proteínas de Ligação a DNA/genética , Modelos Animais de Doenças , Regulação da Expressão Gênica/genética , Humanos , Íntrons/genética , Mutação com Perda de Função , Camundongos , Camundongos Knockout , Mutação/genética , Splicing de RNA/genética , Superóxido Dismutase-1/genética , Proteína com Valosina/genética
16.
J Anat ; 237(4): 603-617, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32533580

RESUMO

The neuromuscular junction (NMJ) is the highly specialised peripheral synapse formed between lower motor neuron terminals and muscle fibres. Post-synaptic acetylcholine receptors (AChRs), which are found in high density in the muscle membrane, bind to acetylcholine released into the synaptic cleft of the NMJ, thereby enabling the conversion of motor action potentials to muscle contractions. NMJs have been studied for many years as a general model for synapse formation, development and function, and are known to be early sites of pathological changes in many neuromuscular diseases. However, information is limited on the diversity of NMJs in different muscles, how synaptic morphology changes during development, and the relevance of these parameters to neuropathology. Here, this crucial gap was addressed using a robust and standardised semi-automated workflow called NMJ-morph to quantify features of pre- and post-synaptic NMJ architecture in an unbiased manner. Five wholemount muscles from wild-type mice were dissected and compared at immature (post-natal day, P7) and early adult (P31-32) timepoints. The inter-muscular variability was greater in mature post-synaptic AChR morphology than that of the pre-synaptic motor neuron terminal. Moreover, the developing NMJ showed greater differences across muscles than the mature synapse, perhaps due to the observed distinctions in synaptic growth between muscles. Nevertheless, the amount of nerve to muscle contact was consistent, suggesting that pathological denervation can be reliably compared across different muscles in mouse models of neurodegeneration. Additionally, mature post-synaptic endplate diameters correlated with fibre type, independently of muscle fibre diameter. Altogether, this work provides detailed information on healthy pre- and post-synaptic NMJ morphology from five anatomically and functionally distinct mouse muscles, delivering useful reference data for future comparison with neuromuscular disease models.


Assuntos
Envelhecimento/fisiologia , Músculo Esquelético/anatomia & histologia , Junção Neuromuscular/anatomia & histologia , Receptores Colinérgicos/metabolismo , Fatores Etários , Animais , Camundongos , Neurônios Motores/metabolismo , Músculo Esquelético/crescimento & desenvolvimento , Músculo Esquelético/metabolismo , Junção Neuromuscular/crescimento & desenvolvimento , Junção Neuromuscular/metabolismo
17.
Cell Rep Med ; 1(1)2020 04 21.
Artigo em Inglês | MEDLINE | ID: mdl-32483558

RESUMO

Clonal evolution of osimertinib-resistance mechanisms in EGFR mutant lung adenocarcinoma is poorly understood. Using multi-region whole-exome and RNA sequencing of prospectively collected pre- and post-osimertinib-resistant tumors, including at rapid autopsies, we identify a likely mechanism driving osimertinib resistance in all patients analyzed. The majority of patients acquire two or more resistance mechanisms either concurrently or in temporal sequence. Focal copy-number amplifications occur subclonally and are spatially and temporally separated from common resistance mutations such as EGFR C797S. MET amplification occurs in 66% (n = 6/9) of first-line osimertinib-treated patients, albeit spatially heterogeneous, often co-occurs with additional acquired focal copy-number amplifications and is associated with early progression. Noteworthy osimertinib-resistance mechanisms discovered include neuroendocrine differentiation without histologic transformation, PD-L1, KRAS amplification, and ESR1-AKAP12, MKRN1-BRAF fusions. The subclonal co-occurrence of acquired genomic alterations upon osimertinib resistance will likely require targeting multiple resistance mechanisms by combination therapies.


Assuntos
Acrilamidas/uso terapêutico , Compostos de Anilina/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas , Evolução Clonal , Resistencia a Medicamentos Antineoplásicos/genética , Neoplasias Pulmonares , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Evolução Clonal/efeitos dos fármacos , Evolução Clonal/genética , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Receptores ErbB/genética , Feminino , Heterogeneidade Genética/efeitos dos fármacos , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Mutação , Inibidores de Proteínas Quinases/uso terapêutico , Sequenciamento do Exoma , Adulto Jovem
18.
PLoS Comput Biol ; 15(4): e1006981, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-31034466

RESUMO

Identifying driver mutations in cancer is notoriously difficult. To date, recurrence of a mutation in patients remains one of the most reliable markers of mutation driver status. However, some mutations are more likely to occur than others due to differences in background mutation rates arising from various forms of infidelity of DNA replication and repair machinery, endogenous, and exogenous mutagens. We calculated nucleotide and codon mutability to study the contribution of background processes in shaping the observed mutational spectrum in cancer. We developed and tested probabilistic pan-cancer and cancer-specific models that adjust the number of mutation recurrences in patients by background mutability in order to find mutations which may be under selection in cancer. We showed that mutations with higher mutability values had higher observed recurrence frequency, especially in tumor suppressor genes. This trend was prominent for nonsense and silent mutations or mutations with neutral functional impact. In oncogenes, however, highly recurring mutations were characterized by relatively low mutability, resulting in an inversed U-shaped trend. Mutations not yet observed in any tumor had relatively low mutability values, indicating that background mutability might limit mutation occurrence. We compiled a dataset of missense mutations from 58 genes with experimentally validated functional and transforming impacts from various studies. We found that mutability of driver mutations was lower than that of passengers and consequently adjusting mutation recurrence frequency by mutability significantly improved ranking of mutations and driver mutation prediction. Even though no training on existing data was involved, our approach performed similarly or better to the state-of-the-art methods.


Assuntos
Códon/genética , Replicação do DNA/genética , Mutação/genética , Mutação/fisiologia , Neoplasias/genética , Biologia Computacional , Humanos , Oncogenes/genética
19.
Cell Rep ; 26(10): 2651-2666.e6, 2019 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-30840888

RESUMO

Intratumor mutational heterogeneity has been documented in primary non-small-cell lung cancer. Here, we elucidate mechanisms of tumor evolution and heterogeneity in metastatic thoracic tumors (lung adenocarcinoma and thymic carcinoma) using whole-exome and transcriptome sequencing, SNP array for copy-number alterations (CNAs), and mass-spectrometry-based quantitative proteomics of metastases obtained by rapid autopsy. APOBEC mutagenesis, promoted by increased expression of APOBEC3 region transcripts and associated with a high-risk APOBEC3 germline variant, correlated with mutational tumor heterogeneity. TP53 mutation status was associated with APOBEC hypermutator status. Interferon pathways were enriched in tumors with high APOBEC mutagenesis and IFN-γ-induced expression of APOBEC3B in lung adenocarcinoma cells, suggesting that the immune microenvironment may promote mutational heterogeneity. CNAs occurring late in tumor evolution correlated with downstream transcriptomic and proteomic heterogeneity, although global proteomic heterogeneity was significantly greater than transcriptomic and CNA heterogeneity. These results illustrate key mechanisms underlying multi-dimensional heterogeneity in metastatic thoracic tumors.


Assuntos
Citidina Desaminase/genética , Neoplasias Torácicas/genética , Desaminases APOBEC , Variações do Número de Cópias de DNA , Heterogeneidade Genética , Mutação em Linhagem Germinativa , Humanos , Mutagênese , Metástase Neoplásica , Proteogenômica/métodos , Neoplasias Torácicas/patologia
20.
Cogn Emot ; 33(2): 146-156, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-29419354

RESUMO

The current study examined the effects of an intervention aimed at blocking the transfer of frustration from a previous experience (i.e. recall task) to a subsequent and unrelated task (i.e. ultimatum bargaining task). Participants who went through the intervention were more likely to accept unfair offers in the ultimatum bargaining task than those who did not go through the intervention. These results show that participants who were blocked from transferring their feelings of frustration from the recall task to the subsequent bargaining task (no-transfer condition) more likely accepted unfair offers than those who inadvertently transferred their feelings of frustration (transfer condition). The effect of conditions on accept-reject decisions in the ultimatum bargaining was mediated by reported feelings of frustration.


Assuntos
Tomada de Decisões , Frustração , Jogos Experimentais , Negociação/psicologia , Adulto , Feminino , Humanos , Masculino , Estudantes/psicologia , Adulto Jovem
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