Mechanophysiology and -pathology of multilayer epithelia

This project area aims to contribute to the understanding of the cross-talk between local mechanical cues and adaptation/differentiation in multilayer epithelia. The selected paradigm is the epidermis, which is by far the most extensive epithelial tissue surrounding the entire outer body surface. It is characterized by the arrangement of tightly-coupled keratinocytes in layer-specific configurations, each with unique differentiation features and mechanobiological properties. To work toward elucidation of mechanical cross-talk mechanisms, novel tools have been and still need to be developed to enable layer-specific analyses. Another focus of this project area is the dysregulation of this balance in human diseases, which are often associated with perturbed neuronal perception resulting in pain and itch. The underlying pathomechanisms of mechanosensation and mechanotransduction are not known.

Teams and Projects

Institute of Biological Information Processing (IBI-2): Mechanobiology, Forschungszentrum Jülich (FZJ)

3D-mapping of epidermal tissue mechanobiology during growth and upon wounding

Rudolf Merkel
Principal Investigator
Hajaani Manoharan
Doctoral Researcher
Epidermal cell layers under strain: Analysis and manipulation of mechanoresponse processes in healthy and diseased biomimetic tissue systems
Pauline Eichstedt
Doctoral Researcher
Exchange kinetics of desmosomal proteins under the influence of mechanical stretch
Project overview. Simplified epidermal equivalents are prepared from primary and immortalized healthy keratinocytes or mutated keratinocyte cell lines. They are preconditioned by cyclic mechanical stretching in a self-made device. Subsequently, mechanical, and molecular properties are quantified under external strain and during healing of model wounds. Parallel experiments on skin ensure physiological relevance.
Institute of Molecular and Cellular Anatomy (MOCA), Uniklinik RWTH Aachen

Consequences of keratin mutations on epidermal tissue mechanics and mechanoresponses

Rudolf E. Leube
Principal Investigator
Nicole Schwarz
Junior Supervisor
Elena Honscheid
Associated Doctoral Researcher
Keratins as organizers of cytoskeletal space
Sungjun Yoon
Doctoral Researcher
Combining image restoration and traction force microscopy to study extracellular matrix-dependent keratin filament network plasticity
Kyeongmin Kim
Doctoral Researcher
Consequences of keratin mutations on epidermal tissue mechanics and mechanoresponses
Project overview. (A) shows the high throughput compression devise designed and constructed by the team of Horst Fisher (project area D). (B) highlights the altered response in Pachyonychia congenita (PC)-derived epidermal equivalents. The fluorescence micrographs show sections of wild-type (WT)- and PC-derived (K6aN171del) skin models that were subjected to cyclic compression (47 mbar, 150 mHz, 1h/day, 5 days) or not. The epidermal equivalents were immunostained 4 days after mechanical stress with antibodies against laminin 332 (magenta) to delineate the basement membrane and against keratin 10 (green) to indicate vital suprabasal epidermal layers. Nuclei are stained with Hoechst 33258 (blue). The outermost border of the stratum corneum is demarcated by a dashed line. Scale bars,  50 µm. The histogram at right quantifies the mechanical stress-induced enlargement of the epidermal compartment (including the stratum corneum) in the PC-derived model (mean ± SD). (C) summarizes aspects that are addressed experimentally in the project.
Institute of Neurophysiology, Uniklinik RWTH Aachen

Mechanical triggers in painful skin diseases

Angelika Lampert
Principal Investigator
Ramona Hohnen
Associated Postdoctoral Researcher
Fiona Roll
Doctoral Researcher
Modulation of sensory nerve excitability by a pain-linked variant in Nav1.9 and keratinocytes under mechanical stress
Project overview. (A) Diseases selected for studies on mechanically-induced pain. (B) Neurites from mouse dorsal root ganglions (DRGs) are are guided in the vertical direction by microgels in an Anisogel (left). Presence of peripheral neuronal stem cells (green) improves overall DRG neurite growth (cyan; right). (C) depicts the different components used for keratinocyte-neuron co-cultures: (Left) Fibronectin coating (red) covalently linked to the top of a 3D PEG-based hydrogel. (Middle) Keratinocytes forming a continuous monolayer (green) on top of the fibronectin coated PEG gel. (Right) Co-culture of a mouse DRG (red) with keratinocyte (green)/fibronectin layers on top. Note the neurites approaching the epithelial monolayer. (D) Schemes of methods used to apply mechanical stimulation. (E) shows patch-clamped neurons cultured on top of a patterned light-responsive hydrogel at left. A change in membrane potential is detected when neurites are mechanically stimulated by light-actuated hydrogel deformation pulse (middle). Co-culture of neurons with keratinocytes on top of these hydrogels shows the formation of contact points between neurites and keratinocytes (right).
Institute of Molecular Pharmacology, Division of Pharmacology in Inflammation, Uniklinik RWTH Aachen

Role of ion channels and ADAM-family metalloproteinases in mechanobiology

Andras Ludwig
Principal Investigator
Aaron Babendreyer
Junior Supervisor
Alessa Pabst
Doctoral Researcher
Regulation of the epithelial-endothelial signaling interface by shear stress and substrate stiffness
Project overview. (A) The scheme depicts a model for activation of ADAM10/17-mediated shedding events by mechanical activation of Piezo-1 and TRPV4 in HaCaT cells. The photograph below shows the stretch chamber (from the Merkel team) used for mechanical stimulation at left and a scheme of the co-culture system at right. (B) Piezo-1 is activated by Yoda 1 or mechanical stretch and, in turn, enhances ADAM activity. Conversely, ADAM activity is suppressed by knockdown of Piezo-1 (grey bars). (C) Activation of TRPV4 by GSK1016790A or mechanical stretch induces ADAM activity, which is suppressed by the TRPV4 inhibitor HC067047 (grey bar). The project aims to translate these findings into (patho) physiological settings and functions using primary keratinocytes and organotypic skin models.