Abstract 102: Microanatomy of Intracranial Human Thrombi by Single Nuclei Transcriptomics

Abstract

Introduction: Microvascular dysfunction and inflammation are thought to underlie reperfusion failure following endovascular thrombectomy. Here we present the first study to produce a transcriptome-based cellular landscape of human intracranial thrombi highlighting the importance of cellular plasticity and intercellular communication at the site of occlusion. Methods: We performed single nuclei RNA-sequencing (snRNA-seq) on intracranial human thrombi harvested during revascularization. Unsupervised clustering, data visualization, differential expression and functional gene ontology/pathway analysis were utilized to deconvolve expression data into cell type-specific expression profiles. Thrombi snRNA-seq data were integrated with single cell RNA-seq data from symptomatic and asymptomatic human carotid plaques and healthy brain vasculature to contextualize thrombi in atherosclerotic disease, perform diffusion coefficient analysis, and identify ligand-receptor interactions. Results: Unbiased clustering identified six cellular populations in distinct effector states within the thrombus microenvironment. Functional gene ontology and pathway analysis revealed a monocyte subpopulation in a distinct endothelial-activation and neuroplasticity state, supporting the notion of cellular trans-differentiation and interconversion. Integration with carotid plaque data and diffusion coefficient analysis revealed shared transcriptional programs existing in a continuum, progressing from asymptomatic plaque to embolized thrombus. Ligand-receptor analysis identified macrophage mediated T-cell activation, pro-inflammatory response, immunological synapse stabilization, neuroplasticity, and monocyte trans-endothelial migration. Conclusion: Our novel application of snRNA-seq to thrombectomy specimens provides the highest resolution exploration of cellular differences and a best understanding of individual contextualized cell function to date. This detailed cellular landscape will facilitate mapping novel interventional targets with direct functional relevance and allow for greater personalization of post-reperfusion therapy.