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Nature May 2024Debate remains around the anatomical origins of specific brain cell subtypes and lineage relationships within the human forebrain. Thus, direct observation in the mature...
Debate remains around the anatomical origins of specific brain cell subtypes and lineage relationships within the human forebrain. Thus, direct observation in the mature human brain is critical for a complete understanding of its structural organization and cellular origins. Here we utilize brain mosaic variation within specific cell types as distinct indicators for clonal dynamics, denoted as cell-type-specific mosaic variant barcode analysis. From four hemispheres and two different human neurotypical donors, we identified 287 and 780 mosaic variants, respectively, that were used to deconvolve clonal dynamics. Clonal spread and allele fractions within the brain reveal that local hippocampal excitatory neurons are more lineage-restricted than resident neocortical excitatory neurons or resident basal ganglia GABAergic inhibitory neurons. Furthermore, simultaneous genome transcriptome analysis at both a cell-type-specific and a single-cell level suggests a dorsal neocortical origin for a subgroup of DLX1 inhibitory neurons that disperse radially from an origin shared with excitatory neurons. Finally, the distribution of mosaic variants across 17 locations within one parietal lobe reveals that restriction of clonal spread in the anterior-posterior axis precedes restriction in the dorsal-ventral axis for both excitatory and inhibitory neurons. Thus, cell-type-resolved somatic mosaicism can uncover lineage relationships governing the development of the human forebrain.
Topics: Aged; Female; Humans; Alleles; Cell Lineage; Clone Cells; GABAergic Neurons; Hippocampus; Homeodomain Proteins; Mosaicism; Neocortex; Neural Inhibition; Neurons; Parietal Lobe; Prosencephalon; Single-Cell Analysis; Transcriptome
PubMed: 38600385
DOI: 10.1038/s41586-024-07292-5 -
Gene Aug 2019qRT-PCR requires reliable internal control genes stably expressed in different samples and experimental conditions. The stability of reference genes is rarely tested...
qRT-PCR requires reliable internal control genes stably expressed in different samples and experimental conditions. The stability of reference genes is rarely tested experimentally, especially in developing tissues given the singularity of these samples. Here we evaluated the suitability of a set of reference genes (Actb, Gapdh, Tbp, Pgk1 and Sdha) using samples from early mouse embryo tissues that are widely used in research (somites, prosencephalon and heart) at different developmental stages. The comparative ΔCq method and five software packages (NormFinder, geNorm, BestKeeper, DataAssist and RefFinder) were used to rank the most stable genes while GenEx and GeNorm programs determined the optimal total number of reference genes for a reliable normalization. The ranking of most reliable reference genes was different for each tissue evaluated: (1) in somite from embryos with 16-18 somite pairs stage, the combination of Pgk1 and Actb provided the best normalization and Actb also presented high stability levels at an earlier developmental stage; (2) Gapdh is the most stable gene in prosencephalon in the two developmental stages tested; and (3) in heart samples, Sdha, Gapdh and Actb were the best combination for qPCR normalization. The analysis of these three tissues simultaneously indicated the combination of Gapdh, Actb and Tbp as the most reliable internal control. This study highlights the importance of appropriate reference genes according to the cell type and/or tissue of interest. The data here described can be applied in future research using mouse embryos as a model for mammalian development.
Topics: Animals; Gene Expression Profiling; Gene Expression Regulation, Developmental; Glyceraldehyde-3-Phosphate Dehydrogenases; Heart; Mice; Prosencephalon; Real-Time Polymerase Chain Reaction; Reference Standards; Software; Somites; TATA-Box Binding Protein; Tissue Distribution
PubMed: 31167115
DOI: 10.1016/j.gene.2019.05.042 -
Stem Cell Reports Mar 2023Inhibitory neurons originating from the ventral forebrain are associated with several neurological conditions. Distinct ventral forebrain subpopulations are generated...
Inhibitory neurons originating from the ventral forebrain are associated with several neurological conditions. Distinct ventral forebrain subpopulations are generated from topographically defined zones; lateral-, medial- and caudal ganglionic eminences (LGE, MGE and CGE), yet key specification factors often span across developing zones contributing to difficulty in defining unique LGE, MGE or CGE profiles. Here we use human pluripotent stem cell (hPSC) reporter lines (NKX2.1-GFP and MEIS2-mCherry) and manipulation of morphogen gradients to gain greater insight into regional specification of these distinct zones. We identified Sonic hedgehog (SHH)-WNT crosstalk in regulating LGE and MGE fate and uncovered a role for retinoic acid signaling in CGE development. Unraveling the influence of these signaling pathways permitted development of fully defined protocols that favored generation of the three GE domains. These findings provide insight into the context-dependent role of morphogens in human GE specification and are of value for in vitro disease modeling and advancement of new therapies.
Topics: Humans; Interneurons; Hedgehog Proteins; Neurons; Prosencephalon; Pluripotent Stem Cells
PubMed: 36801004
DOI: 10.1016/j.stemcr.2023.01.010 -
Science Translational Medicine Jun 2017Human forebrain spheroids enable in vitro observation of region-specific neural migration and circuit formation during brain development.
Human forebrain spheroids enable in vitro observation of region-specific neural migration and circuit formation during brain development.
Topics: Humans; Prosencephalon
PubMed: 28592564
DOI: 10.1126/scitranslmed.aan4295 -
Clinical Autonomic Research : Official... Dec 2019The central autonomic network (CAN) is an intricate system of brainstem, subcortical, and cortical structures that play key roles in the function of the autonomic... (Review)
Review
PURPOSE
The central autonomic network (CAN) is an intricate system of brainstem, subcortical, and cortical structures that play key roles in the function of the autonomic nervous system. Prior to the advent of functional neuroimaging, in vivo studies of the human CAN were limited. The purpose of this review is to highlight the contribution of functional neuroimaging, specifically functional magnetic resonance imaging (fMRI), to the study of the CAN, and to discuss recent advances in this area. Additionally, we aim to emphasize exciting areas for future research.
METHODS
We reviewed the existing literature in functional neuroimaging of the CAN. Here, we focus on fMRI research conducted in healthy human subjects, as well as research that has been done in disease states, to understand CAN function. To minimize confounding, papers examining CAN function in the context of cognition, emotion, pain, and affective disorders were excluded.
RESULTS
fMRI has led to significant advances in the understanding of human CAN function. The CAN is composed of widespread brainstem and forebrain structures that are intricately connected and play key roles in reflexive and modulatory control of autonomic function.
CONCLUSIONS
fMRI technology has contributed extensively to current knowledge of CAN function. It holds promise to serve as a biomarker in disease states. With ongoing advancements in fMRI technology, there is great opportunity and need for future research involving the CAN.
Topics: Brain Stem; Functional Neuroimaging; Humans; Magnetic Resonance Imaging; Prosencephalon
PubMed: 30470943
DOI: 10.1007/s10286-018-0577-0 -
Neuroendocrinology 2015The semaphorin proteins, which contribute to the morphogenesis and homeostasis of a wide range of systems, are among the best-studied families of guidance cues. Much... (Review)
Review
The semaphorin proteins, which contribute to the morphogenesis and homeostasis of a wide range of systems, are among the best-studied families of guidance cues. Much recent research has focused on the role of semaphorins in the development and adult activity of hormone systems and, reciprocally, how circulating reproductive hormones regulate their expression and function. Specifically, several reports have focused on the molecular mechanisms underlying the effects of semaphorins on the migration, survival and structural and functional plasticity of neurons that secrete gonadotropin-releasing hormone (GnRH), essential for the acquisition and maintenance of reproductive competence in mammals. Alterations in the development of this neuroendocrine system lead to anomalous or absent GnRH secretion, resulting in heterogeneous reproductive disorders such as congenital hypogonadotropic hypogonadism (CHH) or other conditions characterized by infertility or subfertility. This review summarizes current knowledge of the role of semaphorins and their receptors on the development, differentiation and plasticity of the GnRH system. In addition, the involvement of genetic deficits in semaphorin signaling in some forms of CHH in humans is discussed.
Topics: Animals; Cell Movement; Gonadotropin-Releasing Hormone; Humans; Neurons; Neurosecretory Systems; Olfactory Pathways; Prosencephalon; Reproductive Physiological Phenomena; Semaphorins; Signal Transduction
PubMed: 25967979
DOI: 10.1159/000431021 -
The Journal of Neuroscience : the... Mar 2017Significant migration cues are required to guide and contain newly generated rodent subventricular zone (SVZ) neuroblasts as they transit along the lateral ventricles...
Significant migration cues are required to guide and contain newly generated rodent subventricular zone (SVZ) neuroblasts as they transit along the lateral ventricles and then through the anterior forebrain to their ultimate site of differentiation in the olfactory bulbs (OBs). These cues enforce strict neuroblast spatial boundaries within the dense astroglial meshwork of the SVZ and rostral migratory stream (RMS), yet are permissive to large-scale neuroblast migration. Therefore, the molecular mechanisms that define these cues and control dynamic interactions between migratory neuroblasts and surrounding astrocytes are of particular interest. We found that deletion of EphA4 and specifically ablation of EphA4 kinase activity resulted in misaligned neuroblasts and disorganized astrocytes in the RMS/SVZ, linking EphA4 forward signaling to SVZ and RMS spatial organization, orientation, and regulation. In addition, within a 3 week period, there was a significant reduction in the number of neuroblasts that reached the OB and integrated into the periglomerular layer, revealing a crucial role for EphA4 in facilitating efficient neuroblast migration to the OB. Single-cell analysis revealed that and its binding partners are expressed by subpopulations of neuroblasts and astrocytes within the SVZ/RMS/OB system resulting in a cell-specific mosaic, suggesting complex EphA4 signaling involving both homotypic and heterotypic cell-cell interactions. Together, our studies reveal a novel molecular mechanism involving EphA4 signaling that functions in stem cell niche organization and ultimately neuroblast migration in the anterior forebrain. The subventricular zone neurogenic stem cell niche generates highly migratory neuroblasts that transit the anterior forebrain along a defined pathway to the olfactory bulb. Postnatal and adult brain organization dictates strict adherence to a narrow migration corridor. Subventricular zone neuroblasts are aligned in tightly bundled chains within a meshwork of astrocytes; however, the cell-cell cues that organize this unique, cell-dense migration pathway are largely unknown. Our studies show that forward signaling through the EphA4 tyrosine kinase receptor, mediated by ephrins expressed by subpopulations of neuroblasts and astrocytes, is required for compact, directional organization of neuroblasts and astrocytes within the pathway and efficient transit of neuroblasts through the anterior forebrain to the olfactory bulb.
Topics: Animals; Astrocytes; Cell Communication; Cell Movement; Cells, Cultured; Gene Expression Regulation, Developmental; Male; Mice; Mice, Knockout; Neural Stem Cells; Neurogenesis; Prosencephalon; Receptor, EphA4; Stem Cell Niche
PubMed: 28258169
DOI: 10.1523/JNEUROSCI.3738-16.2017 -
Development (Cambridge, England) Jun 2015Neurogenesis does not stop abruptly at birth, but persists in specific brain regions throughout life. The neural stem cells (NSCs) located in the largest germinal region... (Review)
Review
Neurogenesis does not stop abruptly at birth, but persists in specific brain regions throughout life. The neural stem cells (NSCs) located in the largest germinal region of the forebrain, the ventricular-subventricular zone (V-SVZ), replenish olfactory neurons throughout life. However, V-SVZ NSCs are heterogeneous: they have different embryonic origins and give rise to distinct neuronal subtypes depending on their location. In this Review, we discuss how this spatial heterogeneity arises, how it affects NSC biology, and why its consideration in future studies is crucial for understanding general principles guiding NSC self-renewal, differentiation and specification.
Topics: Body Patterning; Humans; Lateral Ventricles; Neural Stem Cells; Neurogenesis; Prosencephalon
PubMed: 26081572
DOI: 10.1242/dev.119966 -
The Journal of Comparative Neurology Oct 2019The arcopallium, a key avian forebrain region, receives inputs from numerous brain areas and is a major source of descending sensory and motor projections. While there...
The arcopallium, a key avian forebrain region, receives inputs from numerous brain areas and is a major source of descending sensory and motor projections. While there is evidence of arcopallial subdivisions, the internal organization or the arcopallium is not well understood. The arcopallium is also considered the avian homologue of mammalian deep cortical layers and/or amygdalar subdivisions, but one-to-one correspondences are controversial. Here we present a molecular characterization of the arcopallium in the zebra finch, a passerine songbird species and a major model organism for vocal learning studies. Based on in situ hybridization for arcopallial-expressed transcripts (AQP1, C1QL3, CBLN2, CNTN4, CYP19A1, ESR1/2, FEZF2, MGP, NECAB2, PCP4, PVALB, SCN3B, SCUBE1, ZBTB20, and others) in comparison with cytoarchitectonic features, we have defined 20 distinct regions that can be grouped into six major domains (anterior, posterior, dorsal, ventral, medial, and intermediate arcopallium, respectively; AA, AP, AD, AV, AM, and AI). The data also help to establish the arcopallium as primarily pallial, support a unique topography of the arcopallium in passerines, highlight similarities between the vocal robust nucleus of the arcopallium (RA) and AI, and provide insights into the similarities and differences of cortical and amygdalar regions between birds and mammals. We also propose the use of AMV (instead of nucleus taenia/TnA), AMD, AD, and AI as initial steps toward a universal arcopallial nomenclature. Besides clarifying the internal organization of the arcopallium, the data provide a coherent basis for further functional and comparative studies of this complex avian brain region.
Topics: Animals; Finches; Neural Pathways; Prosencephalon
PubMed: 30919954
DOI: 10.1002/cne.24688 -
Neurobiology of Disease May 2018Alzheimer's disease (AD) brain tissue can act as a seed to accelerate aggregation of amyloid-β (Aβ) into plaques in AD transgenic mice. Aβ seeds have been...
Alzheimer's disease (AD) brain tissue can act as a seed to accelerate aggregation of amyloid-β (Aβ) into plaques in AD transgenic mice. Aβ seeds have been hypothesized to accelerate plaque formation in a prion-like manner of templated seeding and intercellular propagation. However, the structure(s) and location(s) of the Aβ seeds remain unknown. Moreover, in contrast to tau and α-synuclein, an in vitro system with prion-like Aβ has not been reported. Here we treat human APP expressing N2a cells with AD transgenic mouse brain extracts to induce inclusions of Aβ in a subset of cells. We isolate cells with induced Aβ inclusions and using immunocytochemistry, western blot and infrared spectroscopy show that these cells produce oligomeric Aβ over multiple replicative generations. Further, we demonstrate that cell lysates of clones with induced oligomeric Aβ can induce aggregation in previously untreated N2a APP cells. These data strengthen the case that Aβ acts as a prion-like protein, demonstrate that Aβ seeds can be intracellular oligomers and for the first time provide a cellular model of nucleated seeding of Aβ.
Topics: Amyloid beta-Peptides; Animals; Cell Line, Tumor; Humans; Intracellular Fluid; Mice; Mice, Transgenic; Plaque, Amyloid; Prion Proteins; Prosencephalon
PubMed: 29414379
DOI: 10.1016/j.nbd.2018.01.015