<b>The role of activator protein-1 (AP-1) complex in diabetes associated atherosclerosis: Insights from single cell RNA sequencing</b>
Authors: Waheed Khan Abdul , Aziz Misbah , C Sourris Karly , KS Lee Man , Dai Aozhi , MD Watson Anna , Maxwell Scott , Sharma Arpeeta , Zhou Ying , E Cooper Mark , C Calkin Anna , J Murphy Andrew , Baratchi Sara , AM Jandeleit-Dahm Karin 
Published: June 2024

<p dir="ltr"><b>Abstract</b></p><p dir="ltr">Despite advances in the treatment of atherosclerotic cardiovascular disease, it 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 utilised to distinguish the proatherogenic transcriptional profile in aortic cells in diabetes using a streptozotocin induced-diabetic <i>Apoe</i><sup><em>-/-</em></sup> 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 and human THP-1 derived macrophages. We then performed a preclinical study using an AP-1 inhibitor in a diabetic <i>Apoe</i><sup><em>-/-</em></sup> 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 diabetic when compared to non-diabetic individuals. 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 <i>Apoe</i><sup><em>-/-</em></sup> mice. This study has identified the AP-1 complex as a novel target, inhibition of which treats the underlying pathobiology of atherosclerosis in diabetes.<br></p><p dir="ltr"><b>Article Highlights</b></p><p dir="ltr">· Cell-specific transcriptional profile of vascular cells in diabetes-associated atherosclerosis is not known.</p><p dir="ltr">· Single cell sequencing analysis not only defined the transcriptional profile of vascular cells in diabetes but also identified the AP-1 complex as one of the important transcription factor complexes in flow mediated endothelial cell activation and foam cell formation.</p><p dir="ltr">· 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.</p><p dir="ltr">· Importantly, inhibition of AP-1 transcription activity with T-5224 attenuated atherosclerosis development <i>in vivo</i> in diabetes.</p>