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Construction of human 3D striato nigral circuitoids to recapitulate medium spiny neuronal projection defects in Huntington disease

ABSTRACT: Striato nigral circuit is composed of medium spiny neuronal projections that were mainly sent from striatum to midbrain substantial nigra (SN), which is essential for regulating motor behaviors. Dysfunction of striato-nigral circuitry may cause a series of motor disabilities which are associated with neurodegenerative disorders, such as Huntington disease (HD). Although the etiology of HD is known as abnormally expanded CAG repeats of the huntingtin gene (HTT), treatment of HD remains tremendous challenges. One possible reason is lack of effective HD model which resembles striato nigral circuitry deficits for the pharmacology studies. Here we first differentiate striatum-like organoids from human pluripotent stem cells, containing functional medium spiny neurons (MSN). We then generated 3D striato nigral circuitoids by assembling striatum-like organoids with midbrain substantial nigra like organoids. With AVV hSYN GFP viral tracing, the extensive MSN projections from striatum to SN are established, which form synaptic connection with dopaminergic neurons and showed the electronic field potentials by labeling striatum like organoids with optogenetic virus. Furthermore, this striato nigral circuitoids exhibited improved calcium activity than individual striatal organoids. Importantly, we further demonstrated the reciprocal projection defects of the HD iPSC derived circuitoids, which could be reversed with the treatment of brain derived nerve factors. Altogether, the striato nigral circuitoids could be used for identifying MSN projection defects, which would be applied as a potential drug test platform for HD.

ORGANISM(S): Homo sapiens

PROVIDER: GSE251684 | GEO | 2024/05/06

REPOSITORIES: GEO

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Project description:Striatal medium spiny neurons (MSN) are critically involved in motor control, and their degeneration is a principal component of Huntington’s disease. We find that the transcription factor Ctip2 (also known as Bcl11b) is central to MSN differentiation and striatal development. Within the striatum, it is expressed by all MSN, while it is excluded from essentially all striatal interneurons. In the absence of Ctip2, MSN do not fully differentiate, as demonstrated by dramatically reduced expression of a large number of MSN markers, including DARPP-32, FOXP1, Chrm4, Reelin, MOR1, GluR1, and Plexin-D1. Furthermore, MSN fail to aggregate into patches, resulting in severely disrupted patch-matrix organization within the striatum. Finally, heterotopic cellular aggregates invade the Ctip2-/- striatum suggesting a failure by MSN to repel these cells in the absence of Ctip2. In order to investigate the molecular mechanisms that underlie Ctip2-dependent differentiation of MSN and that underlie the patch-matrix disorganization in the mutant striatum, we directly compared gene expression between wild type and mutant striatum at P0. Because CTIP2-expressing MSN constitute 90-95% of the neurons within the striatum, we reasoned that we should be able to detect changes in medium spiny neuron gene expression in Ctip2 null mutants. We microdissected out small regions of striatum at matched locations in wild type and Ctip2-/- mutant littermates at P0 and investigated gene expression with Affymetrix microarrays. We selected the 153 most significant genes and further analyzed them to identify a smaller set of genes of potentially high biological relevance. In order to verify the microarray data and define the distribution of the identified genes in the striatum, we performed in situ hybridization or immunohistochemistry for 12 selected genes: Plexin-D1, Ngef, Nectin-3, Kcnip2, Pcp4L1, Neto1, Basonuclin 2, Fidgetin, Semaphorin 3e, Secretagogin, Unc5d, and Neurotensin. We find that all these genes are either specifically downregulated (Plexin-D1, Ngef, Nectin-3 Kcnip2, Pcp4L1, Neto1), or upregulated (Basonuclin 2, Fidgetin, Semaphorin 3e, Secretagogin, Unc5d, Neurotensin), in the Ctip2-/- striatum, confirming and extending the microarray results. Together, these data indicate that Ctip2 is a critical regulator of MSN differentiation, striatal patch development, and the establishment of the cellular architecture of the striatum. Keywords: mutant analysis

Project description:Striatal medium spiny neurons (MSN) are critically involved in motor control, and their degeneration is a principal component of Huntingtonâs disease. We find that the transcription factor Ctip2 (also known as Bcl11b) is central to MSN differentiation and striatal development. Within the striatum, it is expressed by all MSN, while it is excluded from essentially all striatal interneurons. In the absence of Ctip2, MSN do not fully differentiate, as demonstrated by dramatically reduced expression of a large number of MSN markers, including DARPP-32, FOXP1, Chrm4, Reelin, MOR1, GluR1, and Plexin-D1. Furthermore, MSN fail to aggregate into patches, resulting in severely disrupted patch-matrix organization within the striatum. Finally, heterotopic cellular aggregates invade the Ctip2-/- striatum suggesting a failure by MSN to repel these cells in the absence of Ctip2. In order to investigate the molecular mechanisms that underlie Ctip2-dependent differentiation of MSN and that underlie the patch-matrix disorganization in the mutant striatum, we directly compared gene expression between wild type and mutant striatum at P0. Because CTIP2-expressing MSN constitute 90-95% of the neurons within the striatum, we reasoned that we should be able to detect changes in medium spiny neuron gene expression in Ctip2 null mutants. We microdissected out small regions of striatum at matched locations in wild type and Ctip2-/- mutant littermates at P0 and investigated gene expression with Affymetrix microarrays. We selected the 153 most significant genes and further analyzed them to identify a smaller set of genes of potentially high biological relevance. In order to verify the microarray data and define the distribution of the identified genes in the striatum, we performed in situ hybridization or immunohistochemistry for 12 selected genes: Plexin-D1, Ngef, Nectin-3, Kcnip2, Pcp4L1, Neto1, Basonuclin 2, Fidgetin, Semaphorin 3e, Secretagogin, Unc5d, and Neurotensin. We find that all these genes are either specifically downregulated (Plexin-D1, Ngef, Nectin-3 Kcnip2, Pcp4L1, Neto1), or upregulated (Basonuclin 2, Fidgetin, Semaphorin 3e, Secretagogin, Unc5d, Neurotensin), in the Ctip2-/- striatum, confirming and extending the microarray results. Together, these data indicate that Ctip2 is a critical regulator of MSN differentiation, striatal patch development, and the establishment of the cellular architecture of the striatum. Experiment Overall Design: Matched regions of striatum from wild type and Ctip2-/- mice were obtained via 500 Âµm diameter punch biopsies performed in the center of the developing striatum in acutely sectioned 300 Âµm coronal slices of the brain at postnatal day 0 (P0). Sections were matched rostro-caudally between wild type and null mutant tissue, and fiduciary landmarks were used to assure reproducible microdissection of comparable regions. RNA was extracted using the StrataPrep Total RNA Mini Kit (Stratagene, La Jolla, CA), and RNA quality was assayed using a bioanalyzer (Agilent Technologies, Paola Alto, CA). To ensure reproducibility and biological significance, microarrays were performed with RNA samples from three independent wild type, one heterozygote, and four Ctip2-/- mice (biological replicates). Microarray data were normalized using the RMA function within Bioconductor (Irizarry et al., 2003). Statistical significance of gene expression differences between wild type and knockout was determined using Statistical Analysis of Micrarrays (SAM) (Tusher et al., 2001). Using a SAM d-score cutoff of > 2 or < -2, we selected the 153 most significant genes and further analyzed them to identify a smaller set of genes of potentially high biological relevance.

Project description:Implications for neuroprotection in Parkinson's disease Parkinson’s disease and its characteristic symptoms are thought to arise from the progressive degeneration of specific midbrain dopamine (DA) neurons. In humans, DA neurons of the substantia nigra (SN) and their projections to the striatum show selective vulnerability, while neighboring DA neurons of the ventral tegmental area (VTA) are relatively spared from degeneration. This pattern of cell loss is mimicked in humans, primates, and certain rodents by the neurotoxin MPTP. In this study, we aimed to test the hypothesis that there are factors in the VTA that are potentially neuroprotective against MPTP and that these factors change over time. We have found a differential transcriptional response within the cells of the SN and VTA to sustained exposure to a low dose of MPTP. Specifically, the VTA has increased expression of 148 genes as an early response to MPTP and 113 genes as a late response to MPTP toxicity. This response encompasses many areas of cellular function, including protein regulation (Phf6) and ion/metal regulation (PANK2, Car4). Notably, these responses were largely absent from the cells of the SN. Our data show a clear dynamic response in maintaining the homeostasis and viability of the neurons in the VTA that is lacking in the SN after neurotoxin challenge. We used microarrays to analyze the differential response of the substantia nigra (SN) and ventral tegmental area (VTA) to a chronic low dose of the neurotoxin MPTP. Transgenic hTH-GFP mice were treated with MPTP (4mg/kg) for either 2 or 10 days. Control mice were given an equal volume of saline for 10 days. Dopamine neurons from the substantia nigra and ventral tegmental areas of control and MPTP treated animals were laser captured. The RNA was isolated and processed for microarray hybridization. Each group had three biological replicates, for a total of 18 samples. Three each in the following: Control SN, Control VTA, 2 day MPTP SN, 2 day MPTP VTA, 10 day MPTP SN, 10 day MPTP VTA. Samples were log2 transformed and RMA normalized using Agilent Genespring 10.0 GX.

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Construction of human 3D striato nigral circuitoids to recapitulate medium spiny neuronal projection defects in Huntington disease

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