Genetic Ptbp1 depletion does not induce neuronal RNA splicing patterns in mature astrocytes (Bulk RNA-seq)
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE294763 | GEO | 2025/08/06
REPOSITORIES: GEO
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Project description:Neuronal reprogramming of astrocytes poses a promising therapeutic approach to replace degenerating cells with newly converted neurons. Recent studies reported depletion of polyprimidine tract binding protein PTBP1, a repressor of neuronal alternative splicing, could induce astrocyte to neuron conversion and rescue functional deficits in models of neurodegenerative disease, while others disputed the astrocytic origin of converted neurons. Mechanistic understanding of the conversion, or the lack thereof, requires investigating the transcriptomic effects of Ptbp1 loss of function in mature astrocytes on RNA splicing, in conjunction with lineage tracing, which have not yet been examined. Here, we used genetic depletion of Ptbp1 in adult Aldh1l1-Cre/ERT2 reporter mice to determine whether lineage traced Ptbp1 knockout astrocytes exhibited RNA splicing alterations underlying potential neuronal transdifferentiation. Our analysis employed an alternative genetic Ptbp1 knockout mouse model and an extended 12-week window of Ptbp1 knockout to match previous reports of positive conversion. We found no widespread induction of neuronal identity, despite detecting a minuscule fraction of Cre-positive cells with neuronal transcriptomic features following Ptbp1 deletion. Importantly, PTBP1 depletion in mature astrocytes induces splicing alternations unlike neuronal features of alternative splicing. These findings highlight the challenge of targeting astrocytes for neuronal conversion via Ptbp1 knockout and underscore the importance of cellular gene expression profiling and genetic lineage tracing for in vivo studies of cell type conversion.
2025-08-06 | GSE294768 | GEO
Project description:PTBP1 and PTBP2 control alternative splicing programs during neuronal development, but the cellular functions of most PTBP1/2-regulated isoforms remain unknown. We show that PTBP1 guides developmental gene expression by regulating the transcription factor Pbx1. We identify exons that are differentially spliced when mouse embryonic stem cells (ESCs) differentiate into neuronal progenitor cells (NPCs) and neurons, and transition from PTBP1 to PTBP2 expression. We define those exons controlled by PTBP1 in ESCs and NPCs by RNA-seq analysis after PTBP1 depletion and PTBP1 crosslinking-immunoprecipitation. We find that PTBP1 represses Pbx1 exon 7 and the expression of its neuronal isoform Pbx1a in ESC. Using CRISPR-Cas9 to delete regulatory elements for exon 7, we induce Pbx1a expression in ESCs, finding that this activates transcription of specific neuronal genes including known Pbx1 targets. Thus PTBP1 controls the activity of Pbx1 and suppresses its neuronal transcriptional program prior to differentiation. HB9-GFP mESCs were differentiated into mNPCs and mMNs. Poly-A RNA was isolated from isolated populations of mESCs, mNPCs, and mMNs for RNA-sequencing and splicing analyses.
2016-07-03 | E-GEOD-71079 | biostudies-arrayexpress
Project description:PTBP1 and PTBP2 control alternative splicing programs during neuronal development, but the cellular functions of most PTBP1/2-regulated isoforms remain unknown. We show that PTBP1 guides developmental gene expression by regulating the transcription factor Pbx1. We identify exons that are differentially spliced when mouse embryonic stem cells (ESCs) differentiate into neuronal progenitor cells (NPCs) and neurons, and transition from PTBP1 to PTBP2 expression. We define those exons controlled by PTBP1 in ESCs and NPCs by RNA-seq analysis after PTBP1 depletion and PTBP1 crosslinking-immunoprecipitation. We find that PTBP1 represses Pbx1 exon 7 and the expression of its neuronal isoform Pbx1a in ESC. Using CRISPR-Cas9 to delete regulatory elements for exon 7, we induce Pbx1a expression in ESCs, finding that this activates transcription of specific neuronal genes including known Pbx1 targets. Thus PTBP1 controls the activity of Pbx1 and suppresses its neuronal transcriptional program prior to differentiation. 46C mESCs were differentiated in mNPCs. The mNPCs were treated with 10 nM control, Ptbp1, Ptbp2, or Ptbp1 and Ptbp2 siRNAs for 48 hours. The knockdowns were performed using 2 independent sets of siRNAs. Poly-A RNA was isolated for RNA-sequencing and splicing analyses.
2016-07-03 | E-GEOD-70985 | biostudies-arrayexpress
Project description:PTBP1 and PTBP2 control alternative splicing programs during neuronal development, but the cellular functions of most PTBP1/2-regulated isoforms remain unknown. We show that PTBP1 guides developmental gene expression by regulating the transcription factor Pbx1. We identify exons that are differentially spliced when mouse embryonic stem cells (ESCs) differentiate into neuronal progenitor cells (NPCs) and neurons, and transition from PTBP1 to PTBP2 expression. We define those exons controlled by PTBP1 in ESCs and NPCs by RNA-seq analysis after PTBP1 depletion and PTBP1 crosslinking-immunoprecipitation. We find that PTBP1 represses Pbx1 exon 7 and the expression of its neuronal isoform Pbx1a in ESC. Using CRISPR-Cas9 to delete regulatory elements for exon 7, we induce Pbx1a expression in ESCs, finding that this activates transcription of specific neuronal genes including known Pbx1 targets. Thus PTBP1 controls the activity of Pbx1 and suppresses its neuronal transcriptional program prior to differentiation. 46C mESCs were treated with 20 nM control, Ptbp1, Ptbp2, or Ptbp1 and Ptbp2 siRNAs for 72 hours. The knockdowns were performed using 2 independent sets of siRNAs, including one biological replicate. Poly-A RNA was isolated for RNA-sequencing and splicing analyses.
2016-07-03 | E-GEOD-71075 | biostudies-arrayexpress
Project description:PTBP1 and PTBP2 control alternative splicing programs during neuronal development, but the cellular functions of most PTBP1/2-regulated isoforms remain unknown. We show that PTBP1 guides developmental gene expression by regulating the transcription factor Pbx1. We identify exons that are differentially spliced when mouse embryonic stem cells (ESCs) differentiate into neuronal progenitor cells (NPCs) and neurons, and transition from PTBP1 to PTBP2 expression. We define those exons controlled by PTBP1 in ESCs and NPCs by RNA-seq analysis after PTBP1 depletion and PTBP1 crosslinking-immunoprecipitation. We find that PTBP1 represses Pbx1 exon 7 and the expression of its neuronal isoform Pbx1a in ESC. Using CRISPR-Cas9 to delete regulatory elements for exon 7, we induce Pbx1a expression in ESCs, finding that this activates transcription of specific neuronal genes including known Pbx1 targets. Thus PTBP1 controls the activity of Pbx1 and suppresses its neuronal transcriptional program prior to differentiation. 46C mESCs and mNPCs were cross-linked at 100 mJ/cm2. Cell pellets were collected and flash-frozen for iCLIP library preparation. Libraries were subjected to 100 single-end RNA-sequencing.
2016-07-03 | E-GEOD-71178 | biostudies-arrayexpress
Project description:The splicing regulator PTBP2 controls a program of embryonic splicing required for neuronal maturation. The splicing regulatory proteins PTBP1 and PTBP2 show distinct temporal expression profiles in the developing brain. Neuronal progenitor cells predominantly express PTBP1, whereas developing neurons express high levels of PTBP2, which are subsequently reduced late in neuronal maturation. We show here that PTBP2 and the program of splicing it controls are essential to proper neuronal maturation and survival. To investigate its in vivo function, we generated conditional PTBP2 null alleles in mice. Loss of PTBP2 in neuronal progenitor cells leads to neonatal death without gross defects in brain architecture. Mice with specific depletion of PTBP2 in the cortex and forebrain are viable. However over the first three postnatal weeks, when the normal cortex expands and develops mature circuits, the PTBP2 null cortices degenerate. We find that PTBP2-/- neurons cultured from embryonic brain show the same initial viability as wild type cells with proper early marker expression and neurite outgrowth. Strikingly, between 10 and 20 days in culture PTBP2 null neurons undergo a catastrophic failure to mature and die. To assess the target transcripts leading to these phenotypes, we examined the genomewide splicing changes in the PTBP2 null brains. This identified a large number of mis-regulated exons that share a temporal pattern of regulation; in the absence of PTBP2 many isoforms normally found in adults are precociously expressed in the developing brain. Transcripts following this pattern encode essential neuronal proteins affecting neurite growth, pre- and post-synaptic assembly, and synaptic transmission. Our results define a new genetic regulatory program essential for neuronal survival and maturation, where PTBP2 acts to temporarily repress expression of protein isoforms until the final maturation of the neuron. Mice carrying a conditional floxed PTBP2 allele of PTBP2 were crossed to mice carrying Cre recombinase driven by the nestin promoter. The resulting knockout mutant mouse brains were analyzed for changes in gene expression and alternative splicing. Knockout mice were compared to wildtype littermates. Whole mouse brain polyA plus RNA was isolated from three Nestin-cre knockout embryos at embryonic day 18 and compared to three wildtype littermates. RNA was converted to cDNA and used to probe Affymetrix MJAY splicing sensitive microarrays and analysed by Omniviewer to identify changes in splicing.
2013-12-01 | E-GEOD-51738 | biostudies-arrayexpress
Project description:PTBP1 and PTBP2 control alternative splicing programs during neuronal development, but the cellular functions of most PTBP1/2-regulated isoforms remain unknown. We show that PTBP1 guides developmental gene expression by regulating the transcription factor Pbx1. We identify exons that are differentially spliced when mouse embryonic stem cells (ESCs) differentiate into neuronal progenitor cells (NPCs) and neurons, and transition from PTBP1 to PTBP2 expression. We define those exons controlled by PTBP1 in ESCs and NPCs by RNA-seq analysis after PTBP1 depletion and PTBP1 crosslinking-immunoprecipitation. We find that PTBP1 represses Pbx1 exon 7 and the expression of its neuronal isoform Pbx1a in ESC. Using CRISPR-Cas9 to delete regulatory elements for exon 7, we induce Pbx1a expression in ESCs, finding that this activates transcription of specific neuronal genes including known Pbx1 targets. Thus PTBP1 controls the activity of Pbx1 and suppresses its neuronal transcriptional program prior to differentiation. HB9-GFP mESC were transiently transfected with Cas9 and guide RNA sequences to generate heterozygous deletions at the Pbx1 intron 6 locus (Pbx1 I6 +/-). Wild type and (n=3) or Pbx1 I6 +/- (n=5) clones were differentiated in MN media. Samples were harvested at Day 2 of differentiation, and poly-A RNA was isolated for RNA-sequencing and gene expression analyses.
2016-07-03 | E-GEOD-70883 | biostudies-arrayexpress
Project description:PTBP1 is a widely expressed RNA binding protein known to play roles in regulation of alternative pre-mRNA splicing and other post-transcriptional processes. The PTBP2 paralog is expressed in neurons and switching from expression of PTBP1 to PTBP2 regulates a subset of alternative splicing events during neuronal differentiation. The PTBP3 paralog is conserved across vertebrates and is expressed highly in cells of the hematopoietic system. However, the unique non-redundant roles of PTBP3 are currently unclear. We therefore tested the transcriptomic consequences of knocking down PTBP3 in human K562 erythroleukemia cells. K562 cells were treated with two separate siRNAs (Rd5 and Rd9) targeted against all isoforms of PTBP3 or with a control non-specific siRNA (C2). Triplicate samples were used for each of the three experimental conditions. Transcriptome analysis used the Affymetrix HJAY array, allowing detection of changes in alternative splicing and in transcript levels. Despite at least 75% PTBP3 depletion, as monitored by western blot, only modest changes at the transcriptome level were observed.
2016-08-11 | E-MTAB-4847 | biostudies-arrayexpress
Project description:The splicing regulator PTBP2 controls a program of embryonic splicing required for neuronal maturation. The splicing regulatory proteins PTBP1 and PTBP2 show distinct temporal expression profiles in the developing brain. Neuronal progenitor cells predominantly express PTBP1, whereas developing neurons express high levels of PTBP2, which are subsequently reduced late in neuronal maturation. We show here that PTBP2 and the program of splicing it controls are essential to proper neuronal maturation and survival. To investigate its in vivo function, we generated conditional PTBP2 null alleles in mice. Loss of PTBP2 in neuronal progenitor cells leads to neonatal death without gross defects in brain architecture. Mice with specific depletion of PTBP2 in the cortex and forebrain are viable. However over the first three postnatal weeks, when the normal cortex expands and develops mature circuits, the PTBP2 null cortices degenerate. We find that PTBP2-/- neurons cultured from embryonic brain show the same initial viability as wild type cells with proper early marker expression and neurite outgrowth. Strikingly, between 10 and 20 days in culture PTBP2 null neurons undergo a catastrophic failure to mature and die. To assess the target transcripts leading to these phenotypes, we examined the genomewide splicing changes in the PTBP2 null brains. This identified a large number of mis-regulated exons that share a temporal pattern of regulation; in the absence of PTBP2 many isoforms normally found in adults are precociously expressed in the developing brain. Transcripts following this pattern encode essential neuronal proteins affecting neurite growth, pre- and post-synaptic assembly, and synaptic transmission. Our results define a new genetic regulatory program essential for neuronal survival and maturation, where PTBP2 acts to temporarily repress expression of protein isoforms until the final maturation of the neuron. Mice carrying a conditional "floxed" PTBP2 allele of PTBP2 were crossed to mice carrying Cre recombinase driven by either the nestin or Emx1 promoters. The resulting knockout mutant mouse brains were analyzed for changes in gene expression and alternative splicing. Knockout mice were compared to wildtype littermates. Whole mouse brain polyA plus RNA was isolated from two Nestin-cre knockout embryos at embryonic day 18 and compared to two wildtype littermates. Total polyA plus RNA was isolated from the cortices of an Emx-cre knockout and its wildtype littermate at postnatal day 1. This RNA was converted to standard Illumina paired end libraries using the Truseq kit. The Emx sample and control libraries were strand specific through elimination of the second strand of cDNA using the USER enzyme. Libaries were sequenced on an Illumina HiSeq using the standard paired end protocol. Data was analyzed using the Cufflinks pipeline. Splicing analysis was carried out using the SpliceTrap program.
2013-12-01 | E-GEOD-51733 | biostudies-arrayexpress
Project description:PTBP1 and PTBP2 control alternative splicing programs during neuronal development, but the cellular functions of most PTBP1/2-regulated isoforms remain unknown. We show that PTBP1 guides developmental gene expression by regulating the transcription factor Pbx1. We identify exons that are differentially spliced when mouse embryonic stem cells (ESCs) differentiate into neuronal progenitor cells (NPCs) and neurons, and transition from PTBP1 to PTBP2 expression. We define those exons controlled by PTBP1 in ESCs and NPCs by RNA-seq analysis after PTBP1 depletion and PTBP1 crosslinking-immunoprecipitation. We find that PTBP1 represses Pbx1 exon 7 and the expression of its neuronal isoform Pbx1a in ESC. Using CRISPR-Cas9 to delete regulatory elements for exon 7, we induce Pbx1a expression in ESCs, finding that this activates transcription of specific neuronal genes including known Pbx1 targets. Thus PTBP1 controls the activity of Pbx1 and suppresses its neuronal transcriptional program prior to differentiation.
2016-01-01 | GSE71178 | GEO