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Oberst, P.

Publications and source records attributed to Oberst, P..

5 recordsLinked to original sources

Glia-enriched human brain organoids for studying developmental alterations in leukodystrophies

Leukodystrophies (LKD) comprise mostly inherited white matter disorders whose developmental origins and underlying pathomechanisms remain poorly understood. Progress has been limited by restricted access to human primary tissue and by the inability of animal models to fully recapitulate human neurodevelopment. Human induced pluripotent stem cell-derived neural organoids provide an alternative approach, but most culture systems do not capture later, glia-rich developmental stages relevant to these diseases. Recent studies have shown that appropriate patterning cues and long in vitro differentiation can generate neuroglial spheroids comprising multiple neuronal and macroglial populations, including mature oligodendrocytes. Here, we adapt the human oligodendrocyte (hOLS) spheroid platform to establish 3D models of globoid cell leukodystrophy (GLD), 4H leukodystrophy (4H), and Canavan disease (CD). Here we adapt this organoid platform to establish 3D models of globoid cell leukodystrophy (GLD), 4H leukodystrophy (4H), and Canavan disease (CD). Across 150 days of differentiation, hOLS from different genetic backgrounds displayed largely comparable growth kinetics and developmental trajectories, comprising multiple neuroglial cell types with predominantly ventral forebrain and midbrain identities. Comparison of LKD and control hOLS revealed both shared and disease-specific alterations, with prominent transcriptional changes in lysosomal, metabolic, and stress-response pathways. Lineage-resolved pathway analysis further identified signatures across individual LKDs, including mitochondrial and translational stress in GLD glial lineages, disruption of RNA metabolic and cell-cycle pathways in 4H, and prominent astrocyte-centered metabolic dysregulation in CD. Our results establish hOLS as a human 3D in vitro platform for studying the impact of LKD-associated genetic variants on early neural development and for dissecting lineage-specific disease vulnerability.

neuroscience↗

Transcriptional maintenance of cortical somatostatin interneuron subtype identity during migration

Recent work suggests that cortical interneuron diversity arises from genetic mechanisms guided by the interplay of intrinsic developmental patterning and local extrinsic cues. Individual genetic programs underlying subtype identity are at least partly established in postmitotic neural precursors, prior to their tangential migration and integration in the cortical circuitry. Nevertheless, it is unclear how distinct interneuron identities are maintained during their migration and maturation. Sox6 is a transcription factor with an established role in MGE-derived interneuron maturation and positional identity. To determine its role in maintaining somatostatin (Sst)-expressing interneurons subtype identity, we conditionally removed Sox6 in migrating Sst interneurons and assessed the effects on their mature identity using single-cell RNA-sequencing (scRNAseq), in situ hybridization and electrophysiology. Sox6 removal prior to migration in Sst-expressing neurons reduced subtype diversity without affecting overall number of neurons. Seven out of nine Sst-expressing molecular subtypes were absent in the mature primary somatosensory cortex of Sox6-cKO mice, including the Chodl-Nos1-expressing type which has been shown to be specified at, or shortly after, cell cycle exit. The remaining Sst-expressing subtypes in the Sox6-cKO cortex comprised three molecular subtypes, Crh-C1ql3 and Hpse-Cbln4, and a third subtype that seemed to be a molecular hybrid of these subtypes. Moreover, Sox6-cKO cells still expressed genes enriched within the entire class of Sst-expressing neurons, such as Sst, Lhx6, Satb1, Elfn1 and Mafb. Removal of Sox6 at P7, after cells have reached their final destination and begin integration into the network, did not disrupt Chodl-Nos1 marker expression. Our findings suggest that expression of Sox6 during the migratory phase of cortical interneurons is necessary for maintenance of Sst+ subtype identity, indicating that subtype maintenance during migration requires active transcriptional programs.

neuroscience↗

Apical progenitors remain multipotent throughout corticalneurogenesis

The diverse subtypes of excitatory neurons that populate the neocortex are born from progenitors located in the ventricular zone (apical progenitors, APs). During corticogenesis, APs progress through successive temporal states to sequentially generate deep- followed by superficial-layer neurons directly or via the generation of intermediate progenitors (IPs). Yet little is known about the plasticity of AP temporal identity and whether individual progenitor subtypes remain multipotent throughout corticogenesis. To address this question, we used FlashTag (FT), a method to pulse-label and isolate APs in the mouse neocortex with high temporal resolution to fate-map neuronal progeny following heterochronic transplantation of APs into younger embryos. We find that unlike daughter IPs, which lose the ability to generate deep layer neurons when transplanted into a younger host, APs are temporally uncommitted and become molecularly respecified to generate normally earlier-born neuron types. These results indicate that APs are multipotent cells that are able to revert their temporal identity and re-enter past molecular and neurogenic states. AP fate progression thus occurs without detectable fate restriction during the neurogenic period of corticogenesis. These findings identify unforeseen cell-type specific differences in cortical progenitor fate plasticity, which could be exploited for neuroregenerative purposes.

neuroscience↗

Single-cell transcriptional dynamics and origins of neuronal diversity in the developing mouse neocortex

During cortical development, distinct subtypes of glutamatergic neurons are sequentially born and differentiate from dynamic populations of progenitors. The neurogenic competence of these progenitors progresses as corticogenesis proceeds; likewise, newborn neurons transit through sequential states as they differentiate. Here, we trace the developmental transcriptional trajectories of successive generations of apical progenitors (APs) and isochronic cohorts of their daughter neurons using parallel single-cell RNA sequencing between embryonic day (E) 12 and E15 in the mouse cerebral cortex. Our results identify the birthdate- and differentiation stage-related transcriptional dynamics at play during corticogenesis. As corticogenesis proceeds, APs transit through embryonic age-dependent molecular states, which are transmitted to their progeny to generate successive initial daughter cell identities. In neurons, essentially conserved post-mitotic differentiation programs are applied onto these distinct AP-derived ground states, allowing temporally-regulated sequential emergence of specialized neuronal cell types. Molecular temporal patterning of sequentially-born daughter neurons by their respective mother cell thus underlies emergence of neuronal diversity in the neocortex.\n\nOne Sentence SummaryDuring corticogenesis, temporally dynamic molecular birthmarks are transmitted from progenitors to their post-mitotic progeny to generate neuronal diversity.

neuroscience↗

In vivo pulse-labeling of isochronic cohorts of cells in the central nervous system using FlashTag

This protocol describes a fluorescence birthdating technique to label, track and isolate isochronic cohorts of newborn cells in the central nervous system in vivo. Injection of carboxyfluorescein esters into the cerebral ventricle allows pulse-labeling of M-phase progenitors in touch with the ventricle and their progeny across the central nervous system, a procedure we termed FlashTag. Labeled cells can be imaged ex vivo or in fixed tissue, targeted for electrophysiological experiments, or isolated using Fluorescence-Activated Cell Sorting (FACS) for cell culture or (single-cell) RNA-sequencing. The dye is retained for several weeks, allowing labeled cells to be identified postnatally. This protocol describes the labeling procedure using in utero injection, the isolation of live cells using FACS, as well as the processing of labeled tissue using immunohistochemistry.

neuroscience↗