Diverse reprogramming codes for neuronal identity
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ABSTRACT:
PROVIDER: PRJNA445859 | ENA |
REPOSITORIES: ENA
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Project description:The transcriptional programs that establish neuronal identity evolved to produce a rich diversity of neuronal cell types that arise sequentially during development. Remarkably, transient expression of certain transcription factors (TFs) can also endow non-neural cells with neuronal properties. To decipher the relationship between reprogramming factors and transcriptional networks that produce neuronal identity and diversity, we screened ~600 TF pairs and identified 76 that produce induced neurons (iNs) from fibroblasts. By intersecting the transcriptomes of iNs with those of endogenous neurons, we define a “core” cell-autonomous neuronal signature. The iNs also exhibit diversity; each TF pair produces iNs with unique transcriptional patterns that can predict their pharmacological responses. By linking distinct TF input “codes” to defined transcriptional outputs, this study uncovers cell autonomous features of neuronal identity and expands the reprogramming toolbox to enable more facile engineering of induced neurons with desired patterns of gene expression and related functional properties.
2018-05-10 | GSE112381 | GEO
Project description: Not available
| S-EPMC6483730 | biostudies-literature
Project description:Temporal identity factors are sufficient to reprogram developmental competence of neural progenitors and shift cell fate output, but whether they can also reprogram the identity of terminally differentiated cells is unknown. To address this question, we designed a conditional gene expression system that allows rapid screening of potential reprogramming factors in mouse retinal glial cells combined with genetic lineage tracing. Using this assay, we found that co-expression of the early temporal identity transcription factors Ikzf1 and Ikzf4 is sufficient to directly convert Müller glial cells into cells that translocate to the outer nuclear layer (ONL), where photoreceptor cells normally reside. We name these “induced ONL (iONL)” cells. Using genetic lineage tracing, histological, immunohistochemical, and single-cell transcriptome and multiome analyses, we show that expression of Ikzf1/4 in Müller glia in vivo, without retinal injury, mostly generate iONL cells that share molecular characteristics with bipolar cells, although a fraction of them stain for Rxrg, a cone photoreceptor marker. Furthermore, we show that co-expression of Ikzf1 and Ikzf4 can reprogram mouse embryonic fibroblasts to induced neurons (iN) in culture by rapidly remodeling chromatin and activating a neuronal gene expression program. This work uncovers general neuronal reprogramming properties for temporal identity factors in terminally differentiated cells.
2023-05-04 | GSE169519 | GEO
Project description:Although the importance of Notch signaling in brain development is well-known, its specific contribution to cellular reprogramming remains less defined. Here, we use microRNA-induced neurons (miNs) that are directly reprogrammed from human fibroblasts to determine how Notch signaling contributes to neuronal identity. We found that inhibiting Notch signaling led to an increase in neurite extension, while activating Notch signaling had the opposite effect. Surprisingly, Notch inhibition during the first week of reprogramming was both necessary and sufficient to enhance neurite outgrowth at a later timepoint. This timeframe is when the reprogramming miRNAs, miR-9/9* and miR-124, primarily induce a post-mitotic state and erase fibroblast identity. Accordingly, transcriptomic analysis showed that the effect of Notch inhibition was likely due to improvements in fibroblast fate erasure and silencing of anti-neuronal genes. To this effect, we identify MYLIP, whose downregulation in response to Notch inhibition significantly promoted neurite outgrowth. Moreover, Notch inhibition resulted in cells with neuronal transcriptome signature defined by long gene expression at a faster rate than the control, demonstrating the effect of accelerated fate erasure on neuronal fate acquisition. Our results demonstrate the critical role of Notch signaling in mediating morphological changes in miRNA-based neuronal reprogramming of human adult fibroblasts.
2024-01-12 | GSE252626 | GEO
Project description:Although the importance of Notch signaling in brain development is well-known, its specific contribution to cellular reprogramming remains less defined. Here, we use microRNA-induced neurons (miNs) that are directly reprogrammed from human fibroblasts to determine how Notch signaling contributes to neuronal identity. We found that inhibiting Notch signaling led to an increase in neurite extension, while activating Notch signaling had the opposite effect. Surprisingly, Notch inhibition during the first week of reprogramming was both necessary and sufficient to enhance neurite outgrowth at a later timepoint. This timeframe is when the reprogramming miRNAs, miR-9/9* and miR-124, primarily induce a post-mitotic state and erase fibroblast identity. Accordingly, transcriptomic analysis showed that the effect of Notch inhibition was likely due to improvements in fibroblast fate erasure and silencing of anti-neuronal genes. To this effect, we identify MYLIP, whose downregulation in response to Notch inhibition significantly promoted neurite outgrowth. Moreover, Notch inhibition resulted in cells with neuronal transcriptome signature defined by long gene expression at a faster rate than the control, demonstrating the effect of accelerated fate erasure on neuronal fate acquisition. Our results demonstrate the critical role of Notch signaling in mediating morphological changes in miRNA-based neuronal reprogramming of human adult fibroblasts.
2024-01-12 | GSE252733 | GEO
Project description:Ngn2 induces diverse neuronal lineages from human pluripotency
| PRJEB46177 | ENA
Project description:Cellular differentiation involves profound changes in the chromatic landscape, yet the mechanisms by which somatic cell identity is subsequently maintained remain incompletely understood. To further elucidate regulatory pathways that safeguard the somatic state, we performed two comprehensive RNAi screens targeting chromatin factors during transcription factor-mediated reprogramming of mouse fibroblasts to induced pluripotent stem cells (iPSCs). Remarkably, subunits of the chromatin assembly factor-1 (CAF-1) complex emerged as the most prominent hits from both screens, followed by modulators of lysine sumoylation and heterochromatin maintenance. Suppression of CAF-1 increased reprogramming efficiency by several orders of magnitude and facilitated iPSC formation in as little as 4 days. Mechanistically, CAF-1 suppression led to a more accessible chromatin structure at enhancer elements early during reprogramming. These changes were accompanied by a decrease in somatic heterochromatin domains, increased binding of Sox2 to pluripotency-specific targets and activation of associated genes. Notably, suppression of CAF-1 also enhanced the direct conversion of B cells into macrophages and fibroblasts into neurons. Together, our findings reveal the histone chaperone CAF-1 as a novel regulator of somatic cell identity during transcription factor-induced cell fate transitions and provide a potential strategy to modulate cellular plasticity in a regenerative setting. Gene expression analysis in CAF-1 knockdown and Renilla control during early OKSM-induced reprogramming by microarray
2015-12-10 | E-GEOD-72741 | biostudies-arrayexpress
Project description:Transcription factor-induced reprogramming of somatic cells to pluripotency is a very inefficient process, probably due to the existence of important epigenetic barriers that are imposed during differentiation and that contribute to preserve cell identity. In an effort to decipher the molecular nature of these barriers, we followed a genome-wide approach, in which we identified macro histone variants (macroH2A) as highly expressed in human somatic cells but downregulated after reprogramming to pluripotency, as well as strongly induced during differentiation. Knock down of macro histone variants in human keratinocytes increased the efficiency of reprogramming to pluripotency, while overexpression had opposite effects. Genome-wide occupancy profiles show that in human keratinocytes macroH2A.1 preferentially occupies genes that are expressed at low levels and are marked with H3K27me3, including pluripotency-related genes and bivalent developmental regulators, at which its presence prevents the regain of H3K4me2 during reprogramming, over imposing an additional layer of repression that preserves cell identity. Gemone wide occupancy of HA:macroH2A.1 in human keratinocytes
2013-04-03 | E-GEOD-44400 | biostudies-arrayexpress
Project description:Despite the widespread interest in direct neuronal reprogramming, the mechanisms underpinning fate conversion remain largely unknown. Our study revealed a critical time point after which cells either successfully convert into neurons or succumb to cell death. Co-transduction with Bcl-2 greatly improved negotiation of this critical point by faster neuronal differentiation. Surprisingly, mutants with reduced or no affinity for Bax demonstrated that Bcl-2 exerts this effect by an apoptosis-independent mechanism. Consistent with a caspase-independent role, ferroptosis inhibitors potently increased neuronal reprogramming by inhibiting lipid peroxidation occurring during fate conversion. Genome-wide expression analysis confirmed that treatments promoting neuronal reprogramming elicit an anti-oxidative stress response. Importantly, coexpression of Bcl-2 and anti-oxidative treatments lead to an unprecedented improvement in glial-to-neuron conversion after traumatic brain injury in vivo, underscoring the relevance of these pathways in cellular reprograming irrespective of cell type, in vitro and in vivo. We performed gene expression microarray analysis on mouse embryonic fibroblasts transfected with a viral vector for Ascl1 or empty vector. Cells were then cultured in the absence or presence of forskolin
2016-06-29 | E-GEOD-70921 | biostudies-arrayexpress