DOI: 10.1161/str.55.suppl_1.56 ISSN: 0039-2499

Abstract 56: Temporal Blood Exposure in Neural Organoids Stimulates Dynamic Astrocyte Reactivity

Carina Seah, Braxton R Schuldt, James Vicari, Connie Lebakken, Christopher P Kellner
  • Advanced and Specialized Nursing
  • Cardiology and Cardiovascular Medicine
  • Neurology (clinical)

Introduction: The impact of intracerebral hemorrhage (ICH) and timing of surgical evacuation on brain cell types is poorly understood. Here, we identify cell type specific responses to blood exposure in an organoid model of ICH using single cell transcriptomics.

Methods: Human organoids consisting of excitatory/inhibitory neurons, neural progenitor cells (NPC), astrocytes, pericytes, and microglia were generated from induced pluripotent stem cells and treated with 5% blood for 6 or 24 hours. Organoids were dissociated and sequenced (scRNAseq). scRNAseq alignment, filtering, and analysis was performed using cellranger, SoupX, Scrublet, and Seurat in R to cluster and identify the cell type composition of organoids. Associations of expression to blood exposure were conducted with mixed-effect linear models. Significance was determined using Benjamini-Hochberg multiple testing correction (FDR <5%). Pathway enrichment was performed with FUMA at FDR<5%.

Results: We resolved excitatory and inhibitory neurons, NPCs, astrocytes, pericytes, epithelial cells, fibroblasts, and microglia with cell type-specific responses to blood. Long exposure to blood induced significant transcriptomic responses, whereas short exposure did not. Astrocytes were the most reactive cell type to blood exposure, and upregulated pathways included proliferative and catabolic processes. Fibroblasts and epithelial cells showed the most downregulated pathways, including impairment of interferon signaling pathways and metabolism.

Conclusion: Blood exposure induces transcriptomic changes in a temporal and cell type specific manner. Longer exposure to blood induces higher reactivity, and such reactivity is especially mediated by astrocyte upregulation of catabolic and proliferative processes. These results suggest that astrocytes may mediate cerebral response to blood in the setting of ICH, and reinforce early evacuation of ICH as a means to mitigate cellular reactivity.

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