Atomic Force Microscope with Fluorescence Microscope for simultaneous measurements

• Subject Area: Medicine
• Term: Funded in 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 441175622

Endothelial cells form the innermost layer of blood vessels and are exposed to the shear forces of the streaming blood. This ‘strategic positions’ enables the vascular endothelial cells zu control the function of the vessel. Thereby, the surface of endothelial cells can change their mechanical properties and flexible react to different graduations of shear forces. Particularly, the outer shell of endothelial cells can be functionally divided in glycocalyx and cortex which are all highly flexible and reactive. The change between a soft and stiff endothelial surface is of high physiological relevance and regulates the release and bioavailability of vasoactive substances such as the vasodilator nitric oxide (NO): the surface of soft endothelial cells is more deformed by the streaming blood and secrete more NO than stiff endothelial cells. Thus, ‘stiffness’ is a mechanical property which reflects the physiological state of cells and can be seen as hallmark for the function of cells. We could show that a chronically stiff endothelium leads to endothelial dysfunction and contributes to the development of cardiovascular pathologies such as atherosclerosis and hypertension.For many years our group is interested in the analysis and quantification of the mechanical properties of endothelial cells, their function, dysfunction and the underlying cellular mechanisms. By using an Atomic Force Microscope (AFM) it is possible to scan the endothelial surface to quantify the mechanical properties of the cells. With this technique we could show that mechanical stiffness 5) Depends on the cortical cytoskeleton and membrane proteins6) Is a marker for the function of single cells7) Correlates with the bioavailability of vasoactive substances8) Can be manipulated therapeuticallyOur goal for the next years is to elucidate the underlying molecular mechanisms of cell mechanics and to implement this knowledge into a translational approach. Therefore, the mechanical properties of the endothelial surface will be further characterized. In particular, the endothelial glycocalyx is in the focus of our projects. The following points have a high priority:4) Cell mechanic and vascular inflammation5) Pathophysiological changes of endothelial stiffness in the context of disease models (uremia in kidney diseases, acute myocardial infarction, diabetes)6) Genes and hypertensionTo carry out these projects with success, we will quantify the mechanical properties and image endothelial cells with the AFM. In addition, single-cell-force spectroscopy will be employed to quantify adhesion forces between cells (e.g. monocyte – endothelial cell). After my change from University of Münster, Institute of Physiology II to University of Lübeck, Institute of Physiology and the associated development of a new research group, the acquisition of the proposed Nanowizard 4 is imperative for the successful continuation of the projects.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Rasterkraftmikroskop mit Fluoreszenzmikroskop für simultane Messungen
• Instrumentation Group: 5091 Rasterkraft-Mikroskope
• Applicant Institution: Universität zu Lübeck
• Leader: Professorin Dr. Kristina Kusche-Vihrog