Decoding the transcriptome of atherosclerotic plaque at single-cell resolution

Abstract

Atherogenesis involves an interplay of inflammation, tissue remodeling and cellular transdifferentiation (CTD), making it especially difficult to precisely delineate its pathophysiology. Here we examine the single-cell transcriptome of entire atherosclerotic core (AC) plaques and patient-matched proximal adjacent (PA) portions of carotid artery tissue from patients undergoing carotid endarterectomy. We use a novel tissue dissociation strategy, single-cell RNA sequencing, and systems-biology approaches to analyze the transcriptional profiles of six main cell populations and identify key gene drivers of pathogenic biological processes in vascular smooth muscle cells (VSMCs) and endothelial cells (ECs). Our results reveal an anatomic continuum whereby PA cells promote and respond to inflammatory processes and eventually transition through CTD into matrix-secreting cells in the AC. Inflammatory signaling in PA ECs is driven by IL6, while TNFa signaling defines inflammation in both PA ECs and VSMCs. Furthermore, we identify POSTN, SPP1 and IBSP in AC VSMCs, and ITLN1, SCX and S100A4 in AC ECs as key drivers of CTD in the atherosclerotic core. These results establish an anatomic framework for atherogenesis and suggest a site-specific strategy for disruption of disease progression.

Integrated scRNA-seq analysis identifies conserved transcriptomic features of mononuclear phagocytes in mouse and human atherosclerosis

“…As the adventitia is not extracted during the carotid endarterectomy procedure, this indicates that cells with the Resident/Resident-like/LYVE1 + state may be found within human lesions. However, in a recent report, Alsaigh et al performed single-cell analysis of atherosclerotic lesions from 3 patients, where cells from the atherosclerotic core and the proximal adjacent coronary artery were analyzed (59).…”

“…Macrophages with the foam cell signature (APOE, APOC1) were observed in the atherosclerotic core, while LYVE1 enriched macrophages were in the proximal adjacent coronary artery (59). Future investigations employing spatial transcriptomic methods (60) will help shed light on the precise localization of macrophage populations within diseased vessels.…”

Emerging Roles for Neuropilin-2 in Cardiovascular Disease

“…In support of this theory, NRP2 promotes stem-like traits in breast cancer cells via VEGF-driven signalling [ 113 ]. Importantly, although the analysis is not yet peer-reviewed, new single-cell transcriptomic data of human atherosclerotic plaque also implicates NRP2 in VSMC transdifferentiation within the core [ 42 ] ( Figure 5 ). It would, therefore, be of great scientific and therapeutic interest to investigate whether NRP2 expression marks a more plastic VSMC state.…”

“…NRP2 expression is upregulated in SMCs in response to injury [ 38 , 114 ] and pro-inflammatory stimuli [ 69 , 70 ] via Smad3 transcription factor binding to the NRP2 promoter [ 41 ]. NRP2 expression is linked to VSMC transdifferentiation [ 41 , 42 ]. Evidence suggests NRP2 positively regulates PDGFbb-induced VSMC migration and proliferation [ 38 ].…”

“…However, NRPs are now known to partner with a wide variety of transmembrane receptors and therefore modulate numerous signalling pathways [ 23 , 24 ], including those activated by Epidermal Growth Factor (EGF) [ 33 ], Fibroblast Growth Factor (FGF) [ 34 ], Hepatocyte Growth Factor (HGF) [ 35 ], Insulin-like Growth Factor (IGF) [ 36 ], Platelet-Derived Growth Factor (PDGF) [ 37 , 38 ] and Transforming Growth Factor beta (TGFβ) [ 39 ]. As a result, NRPs mediate multiple cellular processes, and dysregulation of their activity has been implicated with several pathological conditions [ 23 , 38 , 40 , 41 , 42 ]. NRPs are expressed by ECs [ 31 ], leukocytes [ 24 ] and VSMCs [ 38 , 40 , 43 , 44 , 45 ] within the vasculature, and are emerging as multifaceted regulators of signalling pathways associated with CVD [ 23 ].…”