Neuronal conversion of pre-labeled astrocyte using adeno-asociated viruses in vivo
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE288733 | GEO | 2025/11/09
REPOSITORIES: GEO
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Project description:GFAP and vimentin deficiency alters gene expression in astrocytes and microglia in wild-type mice and changes the transcriptional response of reactive glia in mouse model for Alzheimer's disease. Reactive astrocytes with an increased expression of intermediate filament (IF) proteins Glial Fibrillary Acidic Protein (GFAP) and Vimentin (VIM) surround amyloid plaques in Alzheimer's disease (AD). The functional consequences of this upregulation are unclear. To identify molecular pathways coupled to IF regulation in reactive astrocytes, and to study the interaction with microglia, we examined WT and APPswe/PS1dE9 (AD) mice lacking either GFAP, or both VIM and GFAP, and determined the transcriptome of cortical astrocytes and microglia from 15- to 18-month-old mice. Genes involved in lysosomal degradation (including several cathepsins) and in inflammatory response (including Cxcl5, Tlr6, Tnf, Il1b) exhibited a higher AD-induced increase when GFAP, or VIM and GFAP, were absent. The expression of Aqp4 and Gja1 displayed the same pattern. The downregulation of neuronal support genes in astrocytes from AD mice was absent in GFAP/VIM null mice. In contrast, the absence of IFs did not affect the transcriptional alterations induced by AD in microglia, nor was the cortical plaque load altered. Visualizing astrocyte morphology in GFAP-eGFP mice showed no clear structural differences in GFAP/VIM null mice, but did show diminished interaction of astrocyte processes with plaques. Microglial proliferation increased similarly in all AD groups. In conclusion, absence of GFAP, or both GFAP and VIM, alters AD-induced changes in gene expression profile of astrocytes, showing a compensation of the decrease of neuronal support genes and a trend for a slightly higher inflammatory expression profile. However, this has no consequences for the development of plaque load, microglial proliferation, or microglial activation. 2 cell types from 6 conditions: cortical microglia and cortical astrocytes from 15-18 month old APPswe/PS1dE9 mice compared to wildtype littermates. Biological replicates: microglia from APPswe/PS1dE9, N=7, microglia from WT, N=7, astrocytes from APPswe/PS1dE9, N=4, microglia from WT, N=4
2015-11-04 | E-GEOD-74614 | biostudies-arrayexpress
Project description:Neuronal conversion of pre-labeled astrocyte using adeno-asociated viruses in vivo
| PRJNA1219162 | ENA
Project description:Direct reprogramming approaches offer an attractive alternative to stem-cell-derived models, allowing the retention of epigenetic information and age-associated cellular phenotypes, as well as a fast method to reach a target cell type. Several groups have previously generated multiple neuronal subtypes, neural progenitor cells, oligodendrocytes, and other cell types directly from fibroblasts. Other groups have had success at the efficient conversion of embryonic fibroblasts to astrocytes but have not yet achieved similar conversion efficiency for adult human fibroblasts. In order to generate astrocytes for the study of adult-stage disorders, we developed an improved direct conversion strategy employing a combination of small molecules to activate specific pathways that induce trans-differentiation of human adult fibroblasts to astrocytes. We demonstrate that this method produces mature GFAP+/S100β+ cells at high efficiency (40-45%), comparable to previous studies utilizing embryonic fibroblasts. Further, Fibroblast-derived induced Astrocytes (FdiAs) are enriched for markers of astrocyte functionality, including ion-channel buffering, gap-junction communication, and glutamate uptake; and exhibit astrocyte-like calcium signaling and neuroinflammatory phenotypes. RNA-Seq analysis indicates an adult rather than fetal astrocytic gene expression signature, with a greater correlation to temporal lobe astrocytes. Fibroblast-derived induced astrocytes provide a useful tool in studying the adult brain and complement existing in vitro models of induced neurons (iNs), providing an additional platform to study late-stage brain disorders.
2024-07-19 | GSE272279 | GEO
Project description:GFAP and vimentin deficiency alters gene expression in astrocytes and microglia in wild-type mice and changes the transcriptional response of reactive glia in mouse model for Alzheimer's disease. Reactive astrocytes with an increased expression of intermediate filament (IF) proteins Glial Fibrillary Acidic Protein (GFAP) and Vimentin (VIM) surround amyloid plaques in Alzheimer's disease (AD). The functional consequences of this upregulation are unclear. To identify molecular pathways coupled to IF regulation in reactive astrocytes, and to study the interaction with microglia, we examined WT and APPswe/PS1dE9 (AD) mice lacking either GFAP, or both VIM and GFAP, and determined the transcriptome of cortical astrocytes and microglia from 15- to 18-month-old mice. Genes involved in lysosomal degradation (including several cathepsins) and in inflammatory response (including Cxcl5, Tlr6, Tnf, Il1b) exhibited a higher AD-induced increase when GFAP, or VIM and GFAP, were absent. The expression of Aqp4 and Gja1 displayed the same pattern. The downregulation of neuronal support genes in astrocytes from AD mice was absent in GFAP/VIM null mice. In contrast, the absence of IFs did not affect the transcriptional alterations induced by AD in microglia, nor was the cortical plaque load altered. Visualizing astrocyte morphology in GFAP-eGFP mice showed no clear structural differences in GFAP/VIM null mice, but did show diminished interaction of astrocyte processes with plaques. Microglial proliferation increased similarly in all AD groups. In conclusion, absence of GFAP, or both GFAP and VIM, alters AD-induced changes in gene expression profile of astrocytes, showing a compensation of the decrease of neuronal support genes and a trend for a slightly higher inflammatory expression profile. However, this has no consequences for the development of plaque load, microglial proliferation, or microglial activation.
2015-11-04 | GSE74614 | GEO
Project description:Proper brain function requires the assembly and function of diverse populations of neurons and glia. Single cell gene expression studies have mostly focused on characterization of neuronal cell diversity; however, recent studies have revealed substantial diversity of glial cells, particularly astrocytes. To better understand glial cell types and their roles in neurobiology, we built a new suite of adeno-associated viral (AAV)-based genetic tools to enable genetic access to astrocytes and oligodendrocytes. These oligodendrocyte and astrocyte enhancer-AAVs were highly specific, showed variable expression levels, and our astrocyte enhancer-AAVs showed multiple distinct expression patterns that reflected the spatial distribution of astrocyte subtypes. To provide the best glial-specific functional tools, several enhancer-AAVs were: optimized for higher expression levels, shown to be functional and specific in rat and macaque, shown to maintain specific activity in epilepsy where traditional promoters changed activity, and used to drive functional transgenes in astrocytes including Cre recombinase and acetylcholine-responsive sensor iAChSnFR. The astrocyte-specific iAChSnFR revealed a clear reward-dependent acetylcholine response in astrocytes of the nucleus accumbens during reinforcement learning. Together, this collection of glial enhancer-AAVs will enable characterization of astrocyte and oligodendrocyte populations and their roles across species, disease states, and behavioral epochs.
2024-06-26 | GSE235987 | GEO
Project description:Direct astrocyte-to-neuron conversion holds promise for in situ neuroregeneration to treat neurodegenerative diseases. However, commonly-used adeno-associated vectors carrying GFAP mini-promoters drive leaky expression of neurogenic factors in endogenous neurons, raising concerns about trans-differentiation validity. Developing inducible, lineage-traceable transgenic mice, we evaluate NeuroD1 effects on astrocyte-to-neuron conversion in spinal cord and brain injury models. Lineage-tracing and single-cell transcriptomics reveal that ectopic NeuroD1 expression promotes robust conversion of reactive astrocytes in lesion cores to neurons at the acute phase of injury, but not in peri-injury astrocytes.
2025-06-18 | GSE290098 | GEO
Project description:Direct reprogramming approaches offer an attractive alternative to stem-cell-derived models, allowing the retention of epigenetic information and age-associated cellular phenotypes. To explore such age-related phenotypes, several groups have generated multiple neuronal subtypes, neural progenitor cells, oligodendrocytes, and other cell types directly from fibroblasts. Other groups have had success at the efficient conversion of embryonic fibroblasts to astrocytes but have not yet achieved similar conversion efficiency for adult human fibroblasts. In order to generate astrocytes for the study of age-related diseases, we developed an improved direct conversion strategy employing a combination of small molecules to activate specific pathways that induce trans-differentiation of human adult fibroblasts to astrocytes. We demonstrate that this method produces mature GFAP+/S100β+ cells at high efficiency (40-45%), comparable to previous studies utilizing embryonic fibroblasts. Further, Fibroblast-derived induced Astrocytes (FdiAs) are enriched for markers of astrocyte functionality, including ion-channel buffering, gap-junction communication, and glutamate uptake; and exhibit astrocyte-like calcium signaling and neuroinflammatory phenotypes. RNA-Seq analysis indicates an adult rather than fetal astrocytic gene expression signature, with a greater correlation to temporal lobe astrocytes. Fibroblast-derived induced astrocytes provide a useful tool in understanding age-associated disease processes and complement existing in vitro models of induced neurons (iNs), providing an additional platform to study late-stage brain disorders.
2024-08-31 | GSE239320 | GEO
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: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 | GSE294763 | GEO
Project description:Astrocyte dysfunction impacts their normal function, including neuronal support, thereby contributing to neurodegenerative pathologies including Alzheimer's disease (AD). Therefore to understand the role of astrocytes in the pathogenesis of age-related disorders we analysed the gene expression profile of astrocytes with respect to Alzheimer-type pathology. The aim of the present study was to combine immuno-LCM and microarray analysis to characterise the astrocyte transcriptome at different Braak stages, and with respect to ApoE genotype, in post-mortem human temporal cortex sampled dervied from the Medical Research Council Cognitive Function and Ageing Study (MRC-CFAS). GFAP-positive astrocytes were isolated from age, sex and brain pH-matched cases derived from the MRC-CFAS cohort, using immuno laser capture microdissection. The extracted RNA was amplified and applied to HGU133 Plus 2.0 Affymetrix gene arrays. Genes were considered differentially expressed if they showed a minimum 1.5 fold change at p<0.02 in all 6 individual cases in each stage of pathology [18 cases in total: 6 cases Braak stages I-II (3 cases carried at least one ApoE epsilon4 allele and 3 were ApoEe4 negative); 6 cases Braak stages III-IV (3 ApoEe4 positive and 3 ApoEe4 negative; 6 cases Braak stages V-VI (3 ApoEe4 positive and 3 ApoEe4 negative)]. keywords: human GFAP-positive astrocytes
2011-06-01 | E-GEOD-29652 | biostudies-arrayexpress