Atherosclerosis, a disease represented by the lumen narrowing of arteries due to plaque formation, is one of the leading causes of death in the United States and most other developed countries. Atherosclerosis occurs likely at vascular branch sites where the vessel walls are exposed to disturbed flow, but not at the straight parts of vessels where laminar flow dominates. Evidence has shown that different flows and the ensuing shear stresses play crucial roles in regulating vascular endothelial cells (ECs), and subsequently endothelium permeability and atherosclerosis. However, it is unclear about the detailed shear stress distribution on EC surface and how ECs sense the spatiotemporal features of these mechanical stimuli to determine patho-physiological outcomes. In this proposal, the PI will develop an elastic molecular biosensor to visualize the shear stress distribution on live EC surfaces, utilizing the fluorescence resonance energy transfer (FRET). A new intracellular molecular biosensor will also be developed. Hence, both the signals of extracellular shear stress and intracellular molecular activity can be visualized in a single live cell. Three specific aims for this career proposal have been proposed: (1) To develop and characterize a FRET-based shear stress biosensor in vitro; (2) To visualize the distribution of shear stress on live ECs under different flow patterns; (3) To visualize extracellular shear stress and intracellular molecular activities simultaneously under different flow patterns. Given the importance of shear stress in endothelium permeability, and subsequently atherosclerosis, the significance of the proposed study can provide new information on the molecular mechanism by which cells sense the spatiotemporal properties of mechanical stimuli and convert them into biochemical/physiological signals. The main educational objective of this proposal is to motivate the high school and undergraduate students toward future career goals as the next generation of leading scientists in bioengineering. The PI will combine the proposed research and education and organize workshops for undergraduate students, featuring live cell imaging, bio-nanotechnology, and mechanobiology. Minorities and women will be particularly encouraged to participate in these workshops so that they are exposed to the fundamental principles and exciting advancement in these interdisciplinary fields. A significant effort will also be invested to bring the fascinating research advancement in the laboratory to the younger generation, i.e. high-school students. Research experiments will be videotaped and distributed through the internet to reach a wide audience of high-school teachers and students. An emphasis will be placed on how the mechanical and biochemical properties of cell can be monitored, measured, manipulated, and modeled to help our understanding of the complex biological system. The ultimate goal of the proposed research is to help the development of new tools for the early diagnosis of diseases related to mechanical force and the improvement of the treatment. The educational impact is to motivate the next generation of students, particularly underrepresented groups, to participate and promote the emerging field of bioengineering, and to bring broad impact to the society within and beyond the university.
