The Role of Activator Protein-1 Complex in Diabetes-Associated Atherosclerosis: Insights From Single-Cell RNA Sequencing.

Despite advances in treatment, atherosclerotic cardiovascular disease remains the leading cause of death in patients with diabetes. Even when risk factors are mitigated, the disease progresses, and thus, newer targets need to be identified that directly inhibit the underlying pathobiology of atherosclerosis in diabetes. A single-cell sequencing approach was used to distinguish the proatherogenic transcriptional profile in aortic cells in diabetes using a streptozotocin-induced diabetic Apoe ^−/− mouse model. Human carotid endarterectomy specimens from individuals with and without diabetes were also evaluated via immunohistochemical analysis. Further mechanistic studies were performed in human aortic endothelial cells (HAECs) and human THP-1–derived macrophages. We then performed a preclinical study using an activator protein-1 (AP-1) inhibitor in a diabetic Apoe ^−/− mouse model. Single-cell RNA sequencing analysis identified the AP-1 complex as a novel target in diabetes-associated atherosclerosis. AP-1 levels were elevated in carotid endarterectomy specimens from individuals with diabetes compared with those without diabetes. AP-1 was validated as a mechanosensitive transcription factor via immunofluorescence staining for regional heterogeneity of endothelial cells of the aortic region exposed to turbulent blood flow and by performing microfluidics experiments in HAECs. AP-1 inhibition with T-5224 blunted endothelial cell activation as assessed by a monocyte adhesion assay and expression of genes relevant to endothelial function. Furthermore, AP-1 inhibition attenuated foam cell formation. Critically, treatment with T-5224 attenuated atherosclerosis development in diabetic Apoe ^−/− mice. This study has identified the AP-1 complex as a novel target, the inhibition of which treats the underlying pathobiology of atherosclerosis in diabetes. Article Highlights: The cell-specific transcriptional profile of vascular cells in diabetes-associated atherosclerosis is not known. Single-cell RNA sequencing analysis not only defined the transcriptional profile of vascular cells in diabetes but also identified the activator protein-1 (AP-1) complex as one of the important transcription factor complexes in flow-mediated endothelial cell activation and foam cell formation. Although previous studies have implicated AP-1 in atherosclerosis, our study has defined the role of AP-1 as a central regulator of a gene expression program linked to endothelial dysfunction and foam cell formation in diabetes. Importantly, inhibition of AP-1 transcription activity with T-5224 attenuated atherosclerosis development in vivo in diabetes. [ABSTRACT FROM AUTHOR]