Retrograde labelling and RNA deep sequencing of olfactory bulb projection neurons [bulk RNA-seq]
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE162655 | GEO | 2020/12/05
REPOSITORIES: GEO
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Project description:Purpose:This work aimed to identify the genetic profiles of piriform projection neurons and characterize their spatial organization within the piriform cortex. Methods: We microdissected the three layers of pirifrom cortex by laser capture (LMD) and performed RNA deep sequencing in order to identify layer-specific molecular markers, we then validated these data by using RNA in situ hybridization and immunohistochemistry.We next performed anterograde neural tracing experiments to identify piriform target regions, and retrograde neural tracing experiments to analyze how piriform projection neurons are organized within piriform cortex.We then combined the analysis of patterns of gene expression with retrograde tracing experiments to identify molecular signatures of the different subclasses of piriform projecting neurons. Results:We show that layers and sub-layers of the piriform cortex can be discriminated by gene expression patterns in adult piriform cortex. We observe that neurons projecting to distinct target areas are localized in distinct layers and express specific genes. We demonstrate that these molecular signatures of piriform projection neurons are maintained in reeler mice, in which cortical lamination is lost and neural positioning is scrambled, suggesting that piriform output connectivity strictly depends on the molecular programm, rather than a proper lamination of the cortex. Conclusion:These results provide important insights into the principles underling the piriform connectivity.
2016-07-13 | GSE70800 | GEO
Project description:To validate different projection targets of already molecularly-defined olfactory bulb projection neurons we used viral targeting specifically into anterior or posterior cortical areas, Fluorescence Activated Nuclei Sorting (FANS) to enrich for olfactory bulb projection neurons, and single-nuclei RNA sequencing (sn-RNA seq) To isolate GFP-labelled nuclei, 1 individual replicate of AON or PCx-injected mice was used. Ipsilateral and controlateral sides were minced separately and placed into two different tubes. The minced tissue was gently homogenized in Nuclei PURE Lysis Buffer and 10% Triton X-100 using an ice-cold dounce and pestle, and filtered two times through a 40 μm cell strainer on ice. After centrifuging at 500 rpm for 5 min at 4 °C, the supernatant was aspirated and gently resuspended in 500 μl of cold buffer (1x of cold Hanks' Balanced Salt Solution HBSS, 1% nuclease-free BSA, RNasin Plus and 1/2000 DRAQ5). Our study identifies molecularly distinct subtypes of mitral cells projecting to anterior or posterior olfactory cortices.
2021-06-09 | GSE176350 | GEO
Project description:Retrograde labelling and RNA deep sequencing of olfactory bulb projection neurons [bulk RNA-seq]
| PRJNA682580 | ENA
Project description:To characterize the molecular diversity of olfactory bulb projection neurons we used viral targeting and Fluorescence Activated Nuclei Sorting (FANS) to enrich for olfactory bulb projection neurons, and single-nuclei RNA sequencing (sn-RNA seq) to comprehensively characterize their transcriptomes. To isolate GFP-labelled nuclei, 3 individual replicates of AON and PCx-injected mice were used. Ipsilateral and controlateral sides were minced separately and placed into two different tubes. The minced tissue was gently homogenized in Nuclei PURE Lysis Buffer and 10% Triton X-100 using an ice-cold dounce and pestle, and filtered two times through a 40 μm cell strainer on ice. After centrifuging at 500 rpm for 5 min at 4 °C, the supernatant was aspirated and gently resuspended in 500 μl of cold buffer (1x of cold Hanks' Balanced Salt Solution HBSS, 1% nuclease-free BSA, RNasin Plus and 1/2000 DRAQ5). Our study identifies molecularly distinct subtypes of mitral and tufted cells.
2020-12-05 | GSE162654 | GEO
Project description:Bulk RNA sequencing of intracortically-projecting neurons at P10
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Project description:Deciphering patterns of connectivity between neurons in the mammalian brain is a critical step toward understanding brain function. Conventional imaging based neuroanatomical tracing methods identify area-to-area or sparse neuron-to-neuron connectivity patterns, but with extremely limited throughput. Recently developed barcode-based connectomics methods can efficiently map large numbers of single-neuron projections, but linking these data to single-cell transcriptomics remains a challenge. Here, we established a retro-AAV barcode-based multiplexed tracing method called MERGE-seq (Multiplexed projection neuRons retroGrade barcodE sequencing), which is capable of simultaneously characterizing the projectome and transcriptome at the single neuron level. We uncovered dedicated and collateral projection patterns of ventromedial prefrontal cortex (vmPFC) neurons to five downstream targets (AI, DMS, BLA, MD and LH). We found that projection-defined vmPFC neurons are molecularly heterogeneous, which are composed of different neuronal subtypes. We further identified transcriptional signatures of various dedicated and bifurcated vmPFC neurons, and verified Pou3f1 as the marker gene of neurons sending collateral axons to DMS and LH. Finally, we fitted our single-neuron connectome/transcriptome data into a machine learning-based model and revealed groups of genes that were predictive of certain projection pattern. In summary, we have developed a new multiplexed technique whose paired connectome and gene expression data can help reveal organizational principles that form neural circuits and process information.
2024-02-25 | GSE210172 | GEO
Project description:Deciphering patterns of connectivity between neurons in the mammalian brain is a critical step toward understanding brain function. Conventional imaging based neuroanatomical tracing methods identify area-to-area or sparse neuron-to-neuron connectivity patterns, but with extremely limited throughput. Recently developed barcode-based connectomics methods can efficiently map large numbers of single-neuron projections, but linking these data to single-cell transcriptomics remains a challenge. Here, we established a retro-AAV barcode-based multiplexed tracing method called MERGE-seq (Multiplexed projection neuRons retroGrade barcodE sequencing), which is capable of simultaneously characterizing the projectome and transcriptome at the single neuron level. We uncovered dedicated and collateral projection patterns of ventromedial prefrontal cortex (vmPFC) neurons to five downstream targets (AI, DMS, BLA, MD and LH). We found that projection-defined vmPFC neurons are molecularly heterogeneous, which are composed of different neuronal subtypes. We further identified transcriptional signatures of various dedicated and bifurcated vmPFC neurons, and verified Pou3f1 as the marker gene of neurons sending collateral axons to DMS and LH. Finally, we fitted our single-neuron connectome/transcriptome data into a machine learning-based model and revealed groups of genes that were predictive of certain projection pattern. In summary, we have developed a new multiplexed technique whose paired connectome and gene expression data can help reveal organizational principles that form neural circuits and process information.
2024-02-25 | GSE210173 | GEO
Project description:The ability to analyze chromatin accessibility at the single-nucleus level is a critical step towards capturing the highly complex mechanisms that regulate gene expression in the human brain, and to functionally characterize the genetic architecture of neuropsychiatric traits. The assay for transposase accessible chromatin (ATAC-seq) has rapidly established itself as a robust means of studying epigenome regulation in bulk tissues and, more recently, at the single-cell level. To facilitate optimal preparation of frozen archival human brain tissue samples for single-nuclear ATAC-seq (snATAC-seq), we assessed the impact of different sample preparation approaches on the quality of snATAC-seq libraries. We tested six conditions, including different fluorescent activated nuclear sorting (FANS) strategies, from nuclei isolated from a sample of human cortical tissue. Using an unbiased computational approach, we were able to identify major cell populations in all snATAC-seq libraries, including those not subjected to FANS. When FANS was used, we observed that the choice of DNA stain impacts the quality of ATAC-seq libraries. Staining samples with DAPI can lead to insufficient detection of open chromatin regions, whereas 7aad provides improved identification of some nuclear sub-populations. We also observed that use of fluorescent dyes (in particular, DAPI) can lead to under-sampling of excitatory neurons. Our work provides guidelines on the trade-offs associated with different nuclear isolation strategies when preparing samples for snATAC-seq.
2022-01-29 | GSE166016 | GEO
Project description:Selective degeneration of striatal projection neurons is one of the main features of Huntington’s disease (HD). The differences between vulnerable and resilient striatal cell types and cell type-specific molecular events associated with HD progression have not been established. Here we employed fluorescence-activated nuclear sorting (FANS) and deep molecular profiling to gain insight into the properties of different cell types of the human striatum in HD and control donors.
2023-12-04 | GSE227729 | GEO
Project description:Neuroanatomical methods enable high-resolution mapping of neural circuitry, but do not allow systematic molecular profiling of neurons based on their connectivity. Here, we report the development of a novel approach for molecularly profiling projective neurons. We show that ribosomes can be labeled with a camelid nanobody raised against GFP and that this system can be engineered to selectively capture translating mRNAs from cells expressing GFP. We generated a transgenic mouse encoding a nanobody-ribosomal protein fusion (Syn-NBL10) and used a retrograde virus (CAV) encoding GFP to immunoprecipitate ribosomes from projection neurons. This enabled us to profile neurons projecting to the nucleus accumbens. The current method provides a new means for profiling neurons based on their projections. Translating mRNAs immunoprecipitated from neurons projecting to the nucleus accumbens. Each Input and IP sample corrspond to a pooled group of 6 mice.
2014-05-22 | E-GEOD-55800 | biostudies-arrayexpress