Biology subjects

Kagermeier, T.

Publications and source records attributed to Kagermeier, T..

4 recordsLinked to original sources

bioRxiv2025

Multiomics analysis identifies VPA-induced changes in neural progenitor cells, ventricular-like regions, and cellular microenvironment in dorsal forebrain organoids

Pharmaceutical agents, such as antiepileptic medications, can cross fetal barriers and affect the developing brain. Prenatal exposure to the antiepileptic drug valproate (VPA) is associated with an increased risk of neurodevelopmental disorders, including congenital malformations and autism spectrum disorder. In animal models and neural organoids, VPA has been shown to alter signaling pathways, such as Wnt pathway, providing insights into VPA-induced neurodevelopmental defects. Here, we exposed dorsal forebrain organoids to VPA for 30 days and examined effects at the tissue, cellular, and molecular level. VPA treatment disrupted ventricular-like regions, indicating defects in cell-cell and cell-matrix interactions. Transcriptomics analysis confirmed altered expression of extracellular matrix (ECM) genes and single cell RNA sequencing analysis identified genes involved in microenvironment sensing, such as cellular mechanosensing and Hippo-YAP/TAZ signaling pathway. Finally, proteomics analysis corroborated that VPA alters the microenvironment of the human dorsal forebrain organoids by disrupting the secretion of ECM proteins. Altogether, our study suggests that VPA-treated dorsal forebrain organoids serve as a model to investigate the role of extracellular processes in brain development and to understand how their disruptions might contribute to neurodevelopmental disorders.

neuroscience↗

bioRxiv2024

Comparing the impact of sample multiplexing approaches for single-cell RNA-sequencing on downstream analysis using cerebellar organoids

Sample multiplexing provides a solution to limited sample throughput in single-cell RNA sequencing (scRNA-seq) experiments. Different strategies for multiplexing are commercially provided by Parse Biosciences combinatorial barcoding (Parse) and 10x Genomics CellPlex combined with microfluidic cell capture (10x). However, the extent to which these two techniques differ when characterizing complex tissues such as regionalized neural organoids and whether data generated from the two techniques can be readily integrated is unknown. Cerebellar organoids are a highly relevant model for understanding evolutionary differences, developmental trajectories, and disease mechanisms of this brain region. However, they have not been extensively characterized through scRNA-seq. Therefore, we compared the two multiplexing techniques, 10x and Parse, using cerebellar organoids derived from three stem cell lines. While both strategies demonstrated technical reproducibility and revealed comparable cellular diversity including the main lineages of cerebellar neurons, we found more stressed cells in 10x than in Parse. Additionally, we observed differences in transcript capture, with Parse covering a higher gene biotype diversity and less mitochondrial and ribosomal protein coding transcripts. In summary, we demonstrate that both techniques provide similar insight into cerebellar organoid biology, but flexibility of experimental design, capture of long transcripts, and the level of cell stress caused by the workflow differ.

genomics↗

bioRxiv2022

Human organoid model of PCH2a recapitulates brain region-specific pathology

Pontocerebellar hypoplasia type 2 a (PCH2a) is a rare, autosomal recessive pediatric disorder with limited treatment options. Its anatomical hallmark is the hypoplasia of the cerebellum and pons accompanied by progressive microcephaly. PCH2a results from a homozygous founder variant in TSEN54, which encodes a tRNA splicing endonuclease (TSEN) complex subunit. Despite the ubiquitous expression of the TSEN complex, the tissue-specific pathological mechanism of PCH2a remains unknown due to a lack of model system. In this study, we developed human models of PCH2a using brain region-specific organoids. We therefore obtained skin biopsies from three affected males with genetically confirmed PCH2a and derived induced pluripotent stem cells (iPSCs). Proliferation and cell death rates were not altered in PCH2a iPSCs. We subsequently differentiated cerebellar and neocortical organoids from control and PCH2a iPSCs. Mirroring clinical neuroimaging findings, PCH2a cerebellar organoids were reduced in size compared to controls starting early in differentiation. We observed milder growth deficits in neocortical PCH2a organoids. While PCH2a cerebellar organoids did not upregulate apoptosis, their stem cell zones showed altered proliferation kinetics, with increased proliferation at day 30 and reduced proliferation at day 50 compared to controls. In summary, we have generated a human model of PCH2a, which provides the foundation for deciphering brain region-specific disease mechanisms.

neuroscience↗

bioRxiv2022

Human brain organoid model of maternal immune activation identifies radial glia cells as selectively vulnerable

Maternal immune activation (MIA) during the critical windows of gestation is correlated with long- term neurodevelopmental deficits in the offspring, including increased risks for autism spectrum disorder (ASD) in humans. Interleukin 6 (IL-6) derived from the gestational parent is one of the major molecular mediators, by which MIA alters the developing brain. In this study, we established a human three-dimensional (3D) in vitro model of MIA by treating induced pluripotent stem cell- derived dorsal forebrain organoids with a constitutively active form of IL-6, Hyper-IL-6. We validated our model by showing that dorsal forebrain organoids express the molecular machinery necessary for responding to Hyper-IL-6 and activate STAT signaling upon Hyper-IL-6 treatment. RNA sequencing analysis revealed the upregulation of major histocompatibility complex class I (MHCI) genes, which have been implicated with ASD. Immunohistochemical analysis as well as single-cell RNA-sequencing revealed a small increase in the proportion of radial glia cells. Single-cell transcriptomic analysis revealed the highest number of differentially expressed genes in radial glia cells with downregulation of genes related to protein translation in line with data from mouse models of MIA. Additionally, we identified differentially expressed genes not found in mouse models of MIA which might drive species-specific responses to MIA. Together, we establish a human 3D model of MIA, which can be used to study the cellular and molecular mechanisms underlying the increased risk for developing disorders such as ASD.

neuroscience↗