Project Summary/Abstract Atherosclerosis is a multifactorial disease accounting for a leading cause of morbidity and mortality. The endothelium, the inner lining of vessel walls, transduces constant and rhythmic wall shear stress (WSS) from blood viscosity and flow. At the medial wall of arterial bifurcation, stable unidirectional laminar flow (S-flow) develops attenuates systemic inflammatory responses, whereas bidirectional and axially misaligned flow in the lateral wall determine focal but eccentric nature of chronic low-grade inflammatory responses, endothelial cell reprogramming and preferential formation of atherosclerotic lesion. Our unbiased scRNA seq and gene ontology analysis suggested that D-flow induces endothelial-to-immune cell like-transition (EndICLT) and pro-atherogenic pathways. However, the pathophysiological significance of EndICLT in vivo and whether it could serve as an anti-atherogenic therapeutic target is yet remains elusive. One of the longstanding technical challenges is interrogating cell signaling machinery and function simultaneously to unravel key mechanisms in action and dynamic changes in pathophysiological milestones. Comprehensive insights into atherosclerosis and endothelial dynamics can be achieved by visualizing multiomic atlas throughout the plaque. Cutting-edge fluorescence microscopy in optically cleared plaque provides qualitative and quantitative evaluations of atherosclerosis. However, current modalities of fluorescence imaging and time demanding procedures of conventional tissue clearing techniques limits high throughput imaging with high spatial resolution. The advent of multi-scale sub- voxel light-sheet fluorescence microscopy combined with a rapid clearing of plaques may address unmet challenges. In this grant, we will use novel approaches of tissue clearing, advanced image acquisition to elucidate flow-sensitive mechanisms, whereby EndICLT promotes atherosclerosis. In Aim1, we will examine whether the novel dichloromethane - histodenz gradient medium clearing technique has potential for rapid extraction of multiomic information in optically cleared plaque. Conventional fluorescence microscopy techniques including wide-field and diffraction-limited confocal microscopy creates interference from out-of-focus illumination and reduced axial penetration depth across the specimen. In Aim 2, we will focus on establishing an advanced imaging platform of LSFM followed by sub-voxel reconstruction (SV-LSFM) and machine-learning based image segmentation for scalable extraction of multiomic features in high spatial resolution. Finally, in Aim 3, we will integrate Aim 1 and 2 to explore key underlying mechanisms in the EndICLT-dependent atherogenesis. Together, these aims will allow a paradigm shift to identify novel therapeutic targets of atherosclerosis. This proposal will allow me to deepen my research experiences and provide a critical support to build a strong foundation for a career in cardiovascular resea...