| 1. |
- Pircs, Karolina, et al.
(författare)
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Distinct subcellular autophagy impairments in induced neurons from patients with Huntington's disease
- 2022
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Ingår i: Brain : a journal of neurology. - : Oxford University Press (OUP). - 1460-2156. ; 145:9, s. 3035-3057
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Tidskriftsartikel (refereegranskat)abstract
- Huntington's disease (HD) is a neurodegenerative disorder caused by CAG expansions in the huntingtin (HTT) gene. Modelling Huntington's disease is challenging, as rodent and cellular models poorly recapitulate the disease as seen in aging humans. To address this, we generated induced neurons (iNs) through direct reprogramming of human skin fibroblasts, which retain age-dependent epigenetic characteristics. HD-iNs displayed profound deficits in autophagy, characterised by reduced transport of late autophagic structures from the neurites to the soma. These neurite-specific alterations in autophagy resulted in shorter, thinner and fewer neurites specifically in HD-iNs. CRISPRi-mediated silencing of HTT did not rescue this phenotype but rather resulted in additional autophagy alterations in ctrl-iNs, highlighting the importance of wild type HTT in normal neuronal autophagy. In summary, our work identifies a distinct subcellular autophagy impairment in adult patient derived Huntington's disease neurons and provides a new rational for future development of autophagy activation therapies.
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| 2. |
- Drouin-Ouellet, Janelle, et al.
(författare)
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REST suppression mediates neural conversion of adult human fibroblasts via microRNA-dependent and -independent pathways
- 2017
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Ingår i: EMBO Molecular Medicine. - : EMBO. - 1757-4684 .- 1757-4676. ; 9:8, s. 1117-1131
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Tidskriftsartikel (refereegranskat)abstract
- Direct conversion of human fibroblasts into mature and functional neurons, termed induced neurons (iNs), was achieved for the first time 6 years ago. This technology offers a promising shortcut for obtaining patient- and disease-specific neurons for disease modeling, drug screening, and other biomedical applications. However, fibroblasts from adult donors do not reprogram as easily as fetal donors, and no current reprogramming approach is sufficiently efficient to allow the use of this technology using patient-derived material for large-scale applications. Here, we investigate the difference in reprogramming requirements between fetal and adult human fibroblasts and identify REST as a major reprogramming barrier in adult fibroblasts. Via functional experiments where we overexpress and knockdown the REST-controlled neuron-specific microRNAs miR-9 and miR-124, we show that the effect of REST inhibition is only partially mediated via microRNA up-regulation. Transcriptional analysis confirmed that REST knockdown activates an overlapping subset of neuronal genes as microRNA overexpression and also a distinct set of neuronal genes that are not activated via microRNA overexpression. Based on this, we developed an optimized one-step method to efficiently reprogram dermal fibroblasts from elderly individuals using a single-vector system and demonstrate that it is possible to obtain iNs of high yield and purity from aged individuals with a range of familial and sporadic neurodegenerative disorders including Parkinson's, Huntington's, as well as Alzheimer's disease.
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| 3. |
- Johansson, Pia A, et al.
(författare)
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A cis-acting structural variation at the ZNF558 locus controls a gene regulatory network in human brain development
- 2022
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Ingår i: Cell Stem Cell. - : Elsevier BV. - 1934-5909 .- 1875-9777. ; 29:1, s. 8-69
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Tidskriftsartikel (refereegranskat)abstract
- The human forebrain has expanded in size and complexity compared to chimpanzees despite limited changes in protein-coding genes, suggesting that gene expression regulation is an important driver of brain evolution. Here, we identify a KRAB-ZFP transcription factor, ZNF558, that is expressed in human but not chimpanzee forebrain neural progenitor cells. ZNF558 evolved as a suppressor of LINE-1 transposons but has been co-opted to regulate a single target, the mitophagy gene SPATA18. ZNF558 plays a role in mitochondrial homeostasis, and loss-of-function experiments in cerebral organoids suggests that ZNF558 influences developmental timing during early human brain development. Expression of ZNF558 is controlled by the size of a variable number tandem repeat that is longer in chimpanzees compared to humans, and variable in the human population. Thus, this work provides mechanistic insight into how a cis-acting structural variation establishes a regulatory network that affects human brain evolution.
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| 4. |
- Grassi, Daniela A., et al.
(författare)
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Profiling of lincRNAs in human pluripotent stem cell derived forebrain neural progenitor cells
- 2020
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Ingår i: Heliyon. - : Elsevier BV. - 2405-8440. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) can be differentiated into many different cell types of the central nervous system. One challenge when using pluripotent stem cells is to develop robust and efficient differentiation protocols that result in homogenous cultures of the desired cell type. Here, we have utilized the SMAD-inhibitors SB431542 and Noggin in a fully defined monolayer culture model to differentiate human pluripotent cells into homogenous forebrain neural progenitors. Temporal fate analysis revealed that this protocol results in forebrain-patterned neural progenitor cells that start to express early neuronal markers after two weeks of differentiation, allowing for the analysis of gene expression changes during neurogenesis. Using this system, we were able to identify many previously uncharacterized long intergenic non-coding RNAs that display dynamic expression during human forebrain neurogenesis. Cell biology; Genetics; Neuroscience; Developmental genetics; Cellular neuroscience; lincRNAs; Forebrain development; Induced pluripotent stem cells; Neural progenitor cells; Differentiation
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| 5. |
- Grassi, Daniela A., et al.
(författare)
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TRIM28 and the control of transposable elements in the brain
- 2019
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Ingår i: Brain Research. - : Elsevier BV. - 0006-8993. ; 1705, s. 43-47
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Forskningsöversikt (refereegranskat)abstract
- TRIM28 is an epigenetic co-repressor protein that mediates transcriptional silencing. TRIM28 participates, together with the large family of Kruppel-associated box domain zinc finger proteins (KRAB-ZFP) transcription factors, in the repression of transposable elements (TE). Recent advances indicate that TRIM28-based repression of TEs occurs in the mammalian brain and may provide beneficial effects through the regulation of transcriptional networks. Here, we provide an overview of TRIM28-related functions, highlighting the role of controlling TEs in neural progenitor cells and discuss how this mechanism may have contributed to the evolution of the complex human brain. Finally, we outline future considerations for the field.
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