Single-Cell Transcriptomics Reveals Endothelial Plasticity During Diabetic Atherogenesis

Abstract

Atherosclerosis is the leading cause of cardiovascular diseases, which is also the primary cause of mortality among diabetic patients. Endothelial cell (EC) dysfunction is a critical early step in the development of atherosclerosis and aggravated in the presence of concurrent diabetes. Although the heterogeneity of the organ-specific ECs has been systematically analyzed at the single-cell level in healthy conditions, their transcriptomic changes in diabetic atherosclerosis remain largely unexplored. Here, we carried out a single-cell RNA sequencing (scRNA-seq) study using EC-enriched single cells from mouse heart and aorta after 12 weeks feeding of a standard chow or a diabetogenic high-fat diet with cholesterol. We identified eight EC clusters, three of which expressed mesenchymal markers, indicative of an endothelial-to-mesenchymal transition (EndMT). Analyses of the marker genes, pathways, and biological functions revealed that ECs are highly heterogeneous and plastic both in normal and atherosclerotic conditions. The metabolic transcriptomic analysis further confirmed that EndMT-derived fibroblast-like cells are prominent in atherosclerosis, with diminished fatty acid oxidation and enhanced biological functions, including regulation of extracellular-matrix organization and apoptosis. In summary, our data characterized the phenotypic and metabolic heterogeneity of ECs in diabetes-associated atherogenesis at the single-cell level and paves the way for a deeper understanding of endothelial cell biology and EC-related cardiovascular diseases.

Dysfunctional Vascular Endothelium as a Driver of Atherosclerosis: Emerging Insights Into Pathogenesis and Treatment

“…First, the proatherogenic endothelium has recently been shown to exist in a “metastable or partial” state of EndMT, where perturbed ECs perform both endothelial and mesenchymal functions ( Helmke et al, 2019 ; Fledderus et al, 2021 ). The metastable nature of EndMT may be further elucidated with next-generation technologies that profile the atherosclerotic plaque and neighboring regions at the single-cell level, as recently used in studies of disturbed flow and endothelial reprogramming ( Andueza et al, 2020 ) and diabetic atherogenesis ( Zhao et al, 2021 ), as well as through the incorporation of computational models that predict endothelial activation and EndMT in various genetic and environmental conditions ( Weinstein et al, 2020 ). Second, although augmentation of EndMT has previously been associated with increased plaque progression ( Chen et al, 2015 ), emerging studies have highlighted a potential protective role of EndMT by maintaining plaque stability in the absence of SMC-derived myofibroblast-like cells ( Evrard et al, 2016 ; Newman et al, 2021 ).…”

Resident Fibroblast MKL1 Is Sufficient to Drive Pro-fibrogenic Response in Mice

“…Although the MKL1 f/f mice seem to exhibit similar phenotypes in different models of tissue fibrosis, it is unlikely that the transcriptomes of cardiac fibroblasts, pulmonary fibroblasts, and renal fibroblasts might be uniformly altered by the loss of MKL1. Recent advances in single-cell RNAsequencing have greatly facilitated the fine-dissecting the dynamic transcriptomic changes in a wide ranges of tissues and organs (Fu et al, 2021;Liang et al, 2021;Ma et al, 2021;Xie et al, 2021;Zhao et al, 2021). Therefore, a comparison of gene expression profiles of the MKL1-null fibroblasts using this stateof-the-art technique in different organs could shed additional insight on the mode of action for MKL1.…”

Acquisition, processing, and single-cell analysis of normal human breast tissues from a biobank

“…Further validation of this classification could be achieved based on the expression patterns of ESR1 and FOXA1 (mature luminal), CD117 , ELF5 , and EHF (luminal progenitor) and TP63 and NFIB (basal cells) ( Lim et al., 2009 , 2010 ; Pellacani et al., 2016 ). Similarly endothelial cells can be annotated using PECAM, CDH5 and VWF expression pattern ( Zhao et al., 2021 ). Fibroblasts can be annotated using Collagen 1A2 (COL1A2) and COL3A1 expression pattern ( Muhl et al., 2020 ).…”