Leukocyte navigation in complex environments

Michael Sixt’s laboratory is interested in morphodynamic processes both at the cellular and at the tissue level. We mainly focus on the immune system and try to understand the molecular and mechanical principles underlying leukocyte dynamics during processes such as migration and intercellular communication. Here we work at the interface of cell biology, immunology and biophysics and currently investigate how the cytoskeleton generates force to deform the cell body, how this force is transduced to the extracellular environment and how the cells are polarized and guided within tissues. To obtain a holistic view of the process we are also studying tissue architecture as well as the distribution and presentation of guidance cues (chemokines) within these tissues. We developed a number of in vitro tools that allow us to observe cytoskeletal dynamics in real time using different life cell imaging approaches. These are all based on advanced light microscopy like total internal reflection, fast confocal and multiphoton technology. We combine these approaches with genetic and pharmacological interference as well as substrate manipulations like surface micropatterning and microfluidics. A general aim of the lab is to test in vitro findings also in the context of living tissues. To this end we also developed ex vivo (tissue explant) and in vivo imaging setups that allow us to monitor leukocytes together with their physiological environment. Finally we are also interested to test the implications of our findings for physiological immune responses.