scholarly journals Dissecting the Causal Mechanism of X-Linked Dystonia-Parkinsonism by Integrating Genome and Transcriptome Assembly

2017 ◽  
Author(s):  
Tatsiana Aneichyk ◽  
William Hendriks ◽  
Rachita Yadav ◽  
David Shin ◽  
Dadi Gao ◽  
...  

X-linked Dystonia-Parkinsonism (XDP) is a Mendelian neurodegenerative disease endemic to the Philippines. We integrated genome and transcriptome assembly with induced pluripotent stem cell-based modeling to identify the XDP causal locus and potential pathogenic mechanism. Genome sequencing identified novel variation that was shared by all probands and three recombination events that narrowed the causal locus to a genomic segment including TAF1. Transcriptome assembly in neural derivative cells discovered novel TAF1 transcripts, including a truncated transcript exclusively observed in probands that involved aberrant splicing and intron retention (IR) associated with a SINE-VNTR-Alu (SVA)-type retrotransposon insertion. This IR correlated with decreased expression of the predominant TAF1 transcript and altered expression of neurodevelopmental genes; both the IR and aberrant TAF1 expression patterns were rescued by CRISPR/Cas9 excision of the SVA. These data suggest a unique genomic cause of XDP and may provide a roadmap for integrative genomic studies in other unsolved Mendelian disorders.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Attila Szabo ◽  
Ibrahim A. Akkouh ◽  
Matthieu Vandenberghe ◽  
Jordi Requena Osete ◽  
Timothy Hughes ◽  
...  

AbstractWhile neurodevelopmental abnormalities have been associated with schizophrenia (SCZ), the role of astroglia in disease pathophysiology remains poorly understood. In the present study, we used a human induced pluripotent stem cell (iPSC)-derived astrocyte model to investigate the temporal patterns of astroglia differentiation during developmental stages critical for SCZ using RNA sequencing. The model generated astrocyte-specific gene expression patterns during differentiation that corresponded well to astroglia-specific expression signatures of in vivo cortical fetal development. Using this model we identified SCZ-specific expression dynamics, and found that SCZ-associated differentially expressed genes were significantly enriched in the medial prefrontal cortex, striatum, and temporal lobe, targeting VWA5A and ADAMTS19. In addition, SCZ astrocytes displayed alterations in calcium signaling, and significantly decreased glutamate uptake and metalloproteinase activity relative to controls. These results implicate novel transcriptional dynamics in astrocyte differentiation in SCZ together with functional changes that are potentially important biological components of SCZ pathology.


2020 ◽  
Vol 21 (15) ◽  
pp. 5319
Author(s):  
Minchul Kim ◽  
Hee Jin Kim ◽  
Wonyoung Koh ◽  
Ling Li ◽  
Hyohoon Heo ◽  
...  

Frontotemporal dementia (FTD) is caused by the progressive degeneration of the frontal and temporal lobes of the brain. Behavioral variant FTD (bvFTD) is the most common clinical subtype of FTD and pathological subtypes of bvFTD are known as FTD-tau, transactive response (TAR) DNA-binding protein 43 (TDP-43), and fused in sarcoma (FUS). Pathological mechanisms of bvFTD are largely unknown. In this study, we investigated the expression of pathological markers, such as p-Tau, TDP-43, and FUS, in the induced pluripotent stem-cell-derived neurons (iPSN) from two sporadic bvFTD patients and one normal subject. We also used an FTD-patient-derived iPSC-line-carrying microtubule-associated protein tau (MAPT) P301L point mutation as positive control for p-Tau expression. Staurosporine (STS) was used to induce cellular stress in order to investigate dynamic cellular responses related to the cell death pathway. As a result, the expression of active caspase-3 was highly increased in the bvFTD-iPSNs compared with control iPSNs in the STS-treated conditions. Other cell-death-related proteins, including Bcl-2-associated X protein (Bax)/Bcl-2 and cytochrome C, were also increased in the bvFTD-iPSNs. Moreover, we observed abnormal expression patterns of TDP-43 and FUS in the bvFTD-iPSNs compared with control iPSNs. We suggest that the iPSC technology might serve as a potential tool to demonstrate neurodegenerative phenotypes of bvFTD, which will be useful for studying pathological mechanisms for FTD as well as related drug screening in the future.


Author(s):  
Nidaa Ababneh ◽  
Jakub Scaber ◽  
Rowan Flynn ◽  
Andrew Douglas ◽  
Martin R. Turner ◽  
...  

AbstractThe G4C2 hexanucleotide repeat expansion (HRE) in C9orf72 is the commonest cause of familial amyotrophic lateral sclerosis (ALS). A number of different methods have been used to generate isogenic control lines using CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 and non-homologous end-joining (NHEJ) by deleting the repeat region with the risk of creating indels and genomic instability. In this study we demonstrate complete correction of an induced pluripotent stem cell (iPSC) line derived from a C9orf72-HRE positive ALS/FTD patient using CRISPR/Cas9 genome editing and homology directed repair (HDR), resulting in replacement of the excised region with a donor template carrying the wild-type repeat size to maintain the genetic architecture of the locus. The isogenic correction of the C9orf72 HRE restored normal expression and methylation at the C9orf72 locus, reduced intron retention in the edited lines, and abolished pathological phenotypes associated with the C9orf72 HRE expansion in iPSC derived motor neurons (iPSMNs).RNA sequencing of the mutant line identified 2220 differentially expressed genes compared to its isogenic control. Enrichment analysis demonstrated an over-representation of ALS relevant pathways, including calcium ion dependent exocytosis, synaptic transport and the KEGG ALS pathway, as well as new targets of potential relevance to ALS pathophysiology.Complete correction of the C9orf72 HRE in iPSMNs by CRISPR/Cas9 mediated HDR provides an ideal model to study the earliest effects of the hexanucleotide expansion on cellular homeostasis and the key pathways implicated in ALS pathophysiology.


2013 ◽  
Vol 305 (6) ◽  
pp. H913-H922 ◽  
Author(s):  
Christine Y. Ivashchenko ◽  
Gordon C. Pipes ◽  
Irina M. Lozinskaya ◽  
Zuojun Lin ◽  
Xu Xiaoping ◽  
...  

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs) have been recently derived and are used for basic research, cardiotoxicity assessment, and phenotypic screening. However, the hiPS-CM phenotype is dependent on their derivation, age, and culture conditions, and there is disagreement as to what constitutes a functional hiPS-CM. The aim of the present study is to characterize the temporal changes in hiPS-CM phenotype by examining five determinants of cardiomyocyte function: gene expression, ion channel functionality, calcium cycling, metabolic activity, and responsiveness to cardioactive compounds. Based on both gene expression and electrophysiological properties, at day 30 of differentiation, hiPS-CMs are immature cells that, with time in culture, progressively develop a more mature phenotype without signs of dedifferentiation. This phenotype is characterized by adult-like gene expression patterns, action potentials exhibiting ventricular atrial and nodal properties, coordinated calcium cycling and beating, suggesting the formation of a functional syncytium. Pharmacological responses to pathological (endothelin-1), physiological (IGF-1), and autonomic (isoproterenol) stimuli similar to those characteristic of isolated adult cardiac myocytes are present in maturing hiPS-CMs. In addition, thyroid hormone treatment of hiPS-CMs attenuated the fetal gene expression in favor of a more adult-like pattern. Overall, hiPS-CMs progressively acquire functionality when maintained in culture for a prolonged period of time. The description of this evolving phenotype helps to identify optimal use of hiPS-CMs for a range of research applications.


2018 ◽  
Author(s):  
Fantuzzi Federica ◽  
Toivonen Sanna ◽  
Schiavo Andrea Alex ◽  
Pachera Nathalie ◽  
Rajaei Bahareh ◽  
...  

2018 ◽  
Author(s):  
Steven Boggess ◽  
Shivaani Gandhi ◽  
Brian Siemons ◽  
Nathaniel Huebsch ◽  
Kevin Healy ◽  
...  

<div> <p>The ability to non-invasively monitor membrane potential dynamics in excitable cells like neurons and cardiomyocytes promises to revolutionize our understanding of the physiology and pathology of the brain and heart. Here, we report the design, synthesis, and application of a new class of fluorescent voltage indicator that makes use of a fluorene-based molecular wire as a voltage sensing domain to provide fast and sensitive measurements of membrane potential in both mammalian neurons and human-derived cardiomyocytes. We show that the best of the new probes, fluorene VoltageFluor 2 (fVF 2) readily reports on action potentials in mammalian neurons, detects perturbations to cardiac action potential waveform in human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes, shows a substantial decrease in phototoxicity compared to existing molecular wire-based indicators, and can monitor cardiac action potentials for extended periods of time. Together, our results demonstrate the generalizability of a molecular wire approach to voltage sensing and highlights the utility of fVF 2 for interrogating membrane potential dynamics.</p> </div>


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