In total, 12,245 cells were recovered for single-cell RNA sequencing analysis from 1 BBA and 2 saccular intracranial aneurysms (IAs). Unbiased clustering using Seurat-based pipeline was used for cellular landscape profiling. Cellchat was used to understand intracellular communications. Furthermore, 10 BBAs and 30 IAs were retrospectively collected for pathological validations like scanning electron microscopy, H&E stain, Masson stain, Verhoeff Van Gielson stain, and immunofluorescence.
Single-cell transcriptome profiled 14 total subclusters in 6 major groups, namely, 6 monocyte/macrophage clusters, 2 T&NK clusters, 3 vascular smooth muscle cell (VSMC) clusters, 1 dendritic cell, 1 B cell, and 1 endothelial cell cluster. The only mural cell identified in BBAs was VSMC-2 cluster, while mural cells in IAs comprise most clusters of VSMCs and endothelial cells. Upregulated genes in BBA-derived VSMCs are related to arterial mineralization and atherosclerosis, such as PTX3, SPP1, LOX, etc., whereas vasodilation and physiological regulatory genes such as MGP, ACTA2, and MYL9 were conversely enriched in conventional IA-derived VSMCs. Immune cells in the BBA were predominantly macrophages, with a low fraction of T&NK cells, while conventional IAs had a higher percentage of T&NK. Gene enrichment analysis suggested that macrophages in BBA were highly enriched in lipid metabolism as well as atherosclerosis. Ligand-receptor interaction suggested that secretory phosphoprotein 1 (also known as osteopontin) played a major role in mediating the intracellular communication between VSMC and macrophages, especially in BBA. Pathological experiments corroborate with the bioinformatic findings and further characterized BBAs as a thin-walled thrombotic aneurysm with severe atherosclerotic lesions, where ApoE+ macrophages and OPN+ mural cells are intimately involved in the inflammation process.
The preexisting intracranial atherosclerosis might predispose the parent artery to the pathogenic occurrence of BBAs. These data shed light on the pathophysiology of intracranial aneurysms and might assist in the further resolution of the complexity in aneurysm pathogenesis.
总共,从1个BBA和2个囊状颅内动脉瘤(IA)中回收12,245个细胞用于单细胞RNA测序分析。使用基于Seurat的管道进行无偏聚类用于细胞景观分析。Cellchat用于理解细胞内通信。此外,回顾性收集了10个BBA和30个IA进行病理验证,如扫描电子显微镜,H&E染色剂,Masson染色,VerhoeffVanGielson染色,和免疫荧光。
单细胞转录组分析了6个主要群体中的14个亚簇,即,6个单核细胞/巨噬细胞簇,2个T&NK集群,3血管平滑肌细胞(VSMC)簇,1树突状细胞,1B细胞,和1个内皮细胞簇。BBA中唯一鉴定的壁细胞是VSMC-2簇,而IA中的壁细胞包含大多数VSMC和内皮细胞簇。BBA来源的VSMCs中的上调基因与动脉矿化和动脉粥样硬化有关,如PTX3,SPP1,LOX,等。,而血管舒张和生理调节基因如MGP,ACTA2和MYL9在常规IA衍生的VSMC中相反地富集。BBA中的免疫细胞主要是巨噬细胞,T和NK细胞比例很低,而传统IAs的T&NK比例较高。基因富集分析表明,BBA中的巨噬细胞在脂质代谢和动脉粥样硬化中高度富集。配体-受体相互作用表明分泌型磷蛋白1(又称骨桥蛋白)在介导VSMC与巨噬细胞的细胞内通讯中起主要作用,尤其是在BBA。病理实验证实了生物信息学发现,并进一步将BBA表征为具有严重动脉粥样硬化病变的薄壁血栓性动脉瘤。其中ApoE+巨噬细胞和OPN+壁细胞密切参与炎症过程。
预先存在的颅内动脉粥样硬化可能使父动脉易于BBA的致病性发生。这些数据揭示了颅内动脉瘤的病理生理学,并可能有助于进一步解决动脉瘤发病机理的复杂性。