Single-Cell Transcriptomics Reveals the Immune Pathogenesis of Isolated Coronary Arteritis Presenting as Refractory In-Stent Restenosis

Abstract

• •
  This study provides the first single-cell transcriptomic characterization of refractory recurrent in-stent restenosis (RISR) using coronary artery blood, revealing immune dysregulation as a key driver rather than traditional mechanical mechanisms.
• •
  Single-cell analysis identifies AP-1–driven monocyte inflammatory activation as a central upstream regulator of vascular smooth muscle cell dysfunction and neointimal hyperplasia.
• •
  Monocyte-specific inhibition of AP-1 via conditional Fos deletion significantly reduces neointimal formation in vivo, demonstrating its causal role in restenosis progression.
• •
  These findings highlight monocyte-centered inflammation as a promising therapeutic target for refractory restenosis.

The aim of the present study was to elucidate the cellular and molecular mechanisms underlying refractory recurrent in-stent restenosis (RISR), thereby facilitating the identification of potential therapeutic targets. Coronary blood samples were obtained from culprit lesions of patients with RISR and non-ISR controls and subjected to single-cell RNA sequencing to comprehensively characterize immune cell heterogeneity and identify pathogenic signaling pathways. Key molecular mechanisms were validated in independent clinical samples using flow cytometry, monocyte-vascular smooth muscle cell (VSMC) coculture systems, and in vitro functional assays. Causality was further assessed using a monocyte-specific Fos knockdown mouse model of carotid wire injury to evaluate its role in vascular remodeling. Results revealed a pronounced inflammatory immune signature in RISR, with marked upregulation of activator protein-1 (AP-1) gene expression and transcriptional activity in monocytes as a central feature. Upstream mechanistic analyses identified the CCL5-CCR1/p38 MAPK axis as a key driver of AP-1 activation, promoting proinflammatory cytokine release and inducing a proliferative phenotypic switch in VSMCs. In vivo, monocyte-specific Fos knockdown significantly attenuated neointimal hyperplasia and luminal stenosis following vascular injury. Targeting monocyte AP-1 signaling may represent a novel therapeutic strategy for refractory restenosis driven by localized coronary inflammation.

The aim of the present study was to elucidate the cellular and molecular mechanisms underlying refractory recurrent in-stent restenosis (RISR), thereby facilitating the identification of potential therapeutic targets. Coronary blood samples were obtained from culprit lesions of patients with RISR and non-ISR controls and subjected to single-cell RNA sequencing to comprehensively characterize immune cell heterogeneity and identify pathogenic signaling pathways. Key molecular mechanisms were validated in independent clinical samples using flow cytometry, monocyte-vascular smooth muscle cell (VSMC) coculture systems, and in vitro functional assays. Causality was further assessed using a monocyte-specific Fos knockdown mouse model of carotid wire injury to evaluate its role in vascular remodeling. Results revealed a pronounced inflammatory immune signature in RISR, with marked upregulation of activator protein-1 (AP-1) gene expression and transcriptional activity in monocytes as a central feature. Upstream mechanistic analyses identified the CCL5-CCR1/p38 MAPK axis as a key driver of AP-1 activation, promoting proinflammatory cytokine release and inducing a proliferative phenotypic switch in VSMCs. In vivo, monocyte-specific Fos knockdown significantly attenuated neointimal hyperplasia and luminal stenosis following vascular injury. Targeting monocyte AP-1 signaling may represent a novel therapeutic strategy for refractory restenosis driven by localized coronary inflammation.

1. Download: Download high-res image (660KB)
2. Download: Download full-size image