ABSTRACT: Identification of the neuronal types that form the specialized circuits controlling distinct behaviors has benefited greatly from the simplicity offered by zebrafish. Electrophysiological studies have shown that additional to connectivity, understanding of circuitry requires identification of functional specializations among individual circuit components, such as those that regulate levels of transmitter release and neuronal excitability. In this study we use single cell RNAseq (scRNAseq) to identify molecular distinctions causal to the unique physiology of primary motoneuron (PMn) function, as well as associated specialized interneurons that are tailored specifically for mediation of the powerful escape response. Generating scRNA-seq datasets that provide both a wide overview of the cellular populations of the spinal cord and a granular view of the zebrafish motor neurons.
Project description:This SuperSeries is composed of the following subset Series: GSE9603: Identification of Phox2b-regulated genes by expression profiling of cranial motoneuron precursors on NIA 15k microarray GSE9619: Identification of Phox2b-regulated genes by expression profiling of cranial motoneuron precursors on NeuroDev microarray Keywords: SuperSeries Refer to individual Series
Project description:The fatal neurodegenerative disorders amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA) are the most common motoneuron disease and genetic cause of infant death, respectively. Various in vitro model systems have been established to investigate motoneuron disease mechanisms - in particular immortalized cell lines and primary neurons. By quantitative mass spectrometry (MS)-based proteomics we here compare the proteomes of primary motoneurons to motoneuron-like cell lines NSC-34 and N2a as well as to non-neuronal control cells at a depth of 10,000 proteins. We use this resource to evaluate the suitability of murine in vitro model systems for cell biological and biochemical analysis of motoneuron disease mechanisms. Individual protein and pathway analysis indicate substantial differences between motoneuron-like cell lines and primary motoneurons, especially for proteins involved in differentiation, cytoskeleton and receptor signaling, whereas common metabolic pathways were more similar. The ALS-associated proteins themselves also showed distinct differences between cell lines and primary motoneurons, providing a molecular basis for understanding fundamental alterations between cell lines and neurons with respect to neuronal pathways with relevance for disease mechanisms. Our study provides a proteomics resource for motoneuron research and presents a paradigm of how MS-based proteomics can be used to evaluate disease model systems
Project description:The fatal neurodegenerative disorders amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA) are the most common motoneuron disease and genetic cause of infant death, respectively. Various in vitro model systems have been established to investigate motoneuron disease mechanisms - in particular immortalized cell lines and primary neurons. By quantitative mass spectrometry (MS)-based proteomics we here compare the proteomes of primary motoneurons to motoneuron-like cell lines NSC-34 and N2a as well as to non-neuronal control cells at a depth of 10,000 proteins. We use this resource to evaluate the suitability of murine in vitro model systems for cell biological and biochemical analysis of motoneuron disease mechanisms. Individual protein and pathway analysis indicate substantial differences between motoneuron-like cell lines and primary motoneurons, especially for proteins involved in differentiation, cytoskeleton and receptor signaling, whereas common metabolic pathways were more similar. The ALS-associated proteins themselves also showed distinct differences between cell lines and primary motoneurons, providing a molecular basis for understanding fundamental alterations between cell lines and neurons with respect to neuronal pathways with relevance for disease mechanisms. Our study provides a proteomics resource for motoneuron research and presents a paradigm of how MS-based proteomics can be used to evaluate disease model systems
Project description:The cochlear nuclear complex (CN), the starting point for all central auditory processing, comprises a suite of neuronal cell types that are highly specialized for neural coding of acoustic signals, yet molecular logic governing cellular specializations remains largely unknown. By combining single-nucleus RNA sequencing and Patch-seq analysis, we reveal a set of transcriptionally distinct cell populations encompassing all previously observed types and discover multiple new subtypes with anatomical and physiological identity. The resulting complete cell-type taxonomy reconciles anatomical position, morphological, physiological, and molecular criteria, enabling determination of molecular basis of the remarkable cellular phenotypes in the CN. In particular, CN cell-type identity is encoded in a transcriptional architecture that orchestrates functionally congruent expression across a small set of gene families to customize projection patterns, input-output synaptic communication, and biophysical features required for encoding distinct aspects of acoustic signals. This high-resolution account of cellular heterogeneity from the molecular to the circuit level illustrates molecular logic for cellular specializations and enables genetic dissection of auditory processing and hearing disorders with unprecedented specificity.
Project description:Hematopoietic stem cells (HSCs) arise in mid-gestation from a specialized hemogenic endothelium (HE). In this process, HE cells undergo a unique fate change termed endothelial-to-hematopoietic transition, or EHT. While induced pluripotent stem cells (iPSCs) give rise to HE with robust hemogenic potential, the generation of bona fide HSCs from iPSCs remains a challenge. Here, we map single cell dynamics of EHT during embryoid body differentiation from iPSCs and integrate it with human embryo datasets to identify key transcriptional differences between in vitro and in vivo cell states. We further map ligand-receptor interactions associated with differential expression of developmental programs in the iPSC system. We found that the expression of endothelial genes was incompletely repressed during iPSC EHT. Elevated FGF signaling by FGF23, an endothelial pathway ligand, was associated with differential gene expression between in vitro and in vivo EHT. Chemical inhibition of FGF signaling during EHT increased HSPC generation in the zebrafish system, while an FGF agonist had the opposite effect. Consistently, chemical inhibition of FGF signaling increased hemogenic output from iPSCs. In summary, we map the dynamics of EHT from iPSCs at single cell resolution and identify ligand-receptor interactions that can be modulated to improve iPSC differentiation protocols. We show, as proof of principle, that chemical inhibition of FGF signaling during EHT improves hematopoietic output in zebrafish and the iPSC system.
Project description:The identification of molecular specializations in cortical circuitry supporting complex behaviors, such as learned vocalizations, requires understanding the neuroanatomical context from which these circuits arise. In songbirds, the robust nucleus of the arcopallium (RA) provides the sole descending projection for fine motor control of vocalizations. Using single nuclei transcriptomics and spatial gene expression mapping in zebra finches, we were able to define cell types and molecular specializations that distinguish RA from adjacent regions involved in non-vocal motor and sensory processing. We describe an RA-specific vocal projection neuron, differential composition of inhibitory neuron subtypes, and unique glial specializations. We show how several cell-specific molecular features arise in a sex-dependent manner during development. Based on the molecular data, we were also able to electrophysiologically probe, for the first time, predicted GABAergic subtypes within RA. To facilitate future utilization of the data, we have developed interactive apps that allow integration of cell level molecular data with developmental and spatial distribution data from our gene expression brain atlas (ZEBrA). With this resource, users can explore molecular specializations of vocal-motor neurons and support cells that likely reflect adaptations key to the physiology and evolution of vocal control circuits.
Project description:Our knowledge about the molecular regulation of zebrafish gonad development and function is very limited. This study aims to identify gonad-expressed genes in zebrafish and to analyze their expression in various organs. Using our custom ÂGonad Uniclone Microarray v1, we performed a total of 32 hybridizations, using eight target organs with four biological replicates each. The target organs consisted of adult ovary and testis; the brain, kidney and rest-of-body (ie. whole body except the three organs listed earlier) from both male and female zebrafish, were used as controls. For simplicity, rest of body will be regarded as an organ. All targets were hybridized against a pooled common reference consisting of equal amounts of targets from all dissected organs from a single adult male and a single adult female.
Project description:In mammals, fine motor control is essential for skilled behavior, and is subserved by specialized subdivisions of the primary motor cortex (M1) and other components of the brain’s motor circuitry. We profiled the epigenomic state of several components of the Rhesus macaque motor system, including subdivisions of M1 corresponding to hand and orofacial control. We compared this to open chromatin data from M1 in rat, mouse, and human. We found broad similarities as well as unique specializations in open chromatin regions (OCRs) between M1 subdivisions and other brain regions, as well as species- and lineage-specific differences reflecting their evolutionary histories. By distinguishing shared mammalian M1 OCRs from primate- and human-specific specializations, we highlight gene regulatory programs that could subserve the evolution of skilled motor behaviors such as speech and tool use. Further, in order to predict candidate enhancers in additional species for which primary data was not available, we developed machine learning models trained on genome sequence across species.
Project description:Zebrafish is capable of endogenously regenerating functional retina pigment epithelium (RPE) after widespread genetic ablation which involves a series of cellular and molecular events that remain to be defined. Here, using the RPE genetic ablation model in zebrafish, we observed that mTOR signaling was activated in the RPE cells post-ablation. Pharmacological and genetic inhibition of mTOR signaling impaired RPE regeneration, while activation of mTOR signaling benefited RPE recovery, suggesting mTOR signaling was required and sufficient for RPE regeneration post-ablation in zebrafish. We further identified an interesting crosstalk between mTOR signaling and microglia/macrophages during RPE regeneration that mTOR acts as an upstream regulator of microglia/macrophage infiltration to the injury site while microglia/macrophage, in turn, rainenforce mTOR activity.
2022-03-01 | GSE174538 | GEO
Project description:Emergent simplicity in microbial community assembly