In multicellular organisms specific stem cell types with distinct developmental potentials occur during development. Transient pluripotent stem cells, which can differentiate into derivatives of all three germ layers (endoderm, ectoderm and mesoderm), are generated during blastocyst development. Adult stem cells, developing at later stages, are more restricted in their potential, since they can differentiate into progenitors and mature effector cell types of only one stem cell system. Adult stem cells have been identified in a variety of tissues in the adult organism and are important for lifelong tissue homeostasis and repair.
Antigen presenting dendritic cells (DC) represent highly specialized immune cells with a central role in immunity and tolerance induction. DC sense antigens, which are taken-up, processed and presented in the context of MHC molecules to elicit antigen specific T cell responses (Zenke and Hieronymus, 2006; Seré et al., 2012). Specific DC subsets exist that differ in surface phenotype, function, activation state and anatomical localization. The main DC subsets are (i) tissue/interstitial DC in organs, now referred to as conventional or classical DC (cDC); (ii) plasmacytoid DC (pDC) in blood that represent the major producers of type 1 interferon (iii) CD8alpha DC in lymphoid tissue and (iv) Langerhans cells (LC), the cutaneous contingent of DC in epidermis.
Cell motility and cytoskeleton dynamics play a fundamental role in many biological events, including embryonic development, wound healing and immune responses, such as phagocytosis and T-cell activation. Regulation of actin cytoskeleton remodelling depends on the activities of several proteins that co-ordinate events, such as actin filament nucleation, elongation, capping and cross-linking, both in space and time. Our studies aim at unravelling molecular mechanisms underlying cytoskeleton-dependent processes and the impact of biomaterials on them.
The Institute of Biomedical Engineering, Department of Cell Biology located at the Medical Faculty of RWTH Aachen University has recently established a new total internal fluorescence reflection/fluorescence recovery after photobleaching (TIRF/FRAP) microscopy system. The TIRF/FRAP system was generously funded by DFG, NRW government and Medical Faculty of RWTH Aachen University.