Project Details
Projekt
Mechanosensation and –response of epidermal systems
Applicants
Dr. Bernd Hoffmann; Professor Dr. Rudolf Merkel
Subject Area
Cell Biology
Biophysics
Biophysics
Term
from 2015 to 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 273723265
The epidermis of skin is a multi-layered epithelial tissue and the first line defense against chemical and mechanical stress. The mechanical barrier function depends on an integrated assembly and reorganization of cell-matrix and cell-cell junctions in the basal layer and on different intercellular junctions in suprabasal layers. However, how stress is recognized and through which adhesive and cytoskeletal components is only poorly understood. On single cell-sheet level, mimicking the basal epidermal layer, we could show that not only focal ad-hesions but also adherens junctions function as vital mechanosensitive elements that recog-nize strain as signal and found a mechanosensitive transition from cell-matrix to cell-cell ad-hesions upon formation of keratinocyte monolayers. Based on these data this project focusses on detailed live-cell analyses of cell-cell junction dependent mechanosensation and –response under mechanical stress. With adherens junc-tions and desmosomes two vital cell-cell adhesion structures together with attached cyto-skeletal components will be analyzed with high spatial and temporal resolution. We will not only analyze live-cell reorientation dynamics of marker proteins (i.e. paxillin, vinculin, α-catenin, E- and P-cadherin, desmoglein, and associated cytoskeleta) but also determine in-fluences of epidermal differentiation/maturation on mechanosensitivity. Regulations on the molecular level regarding protein exchange dynamics will be analyzed by FRAP in the ab-sence and presence of mechanical stress. Using identical stress conditions, we will charac-terize cooperative response behavior for adherens junction dependent mechanosensitivity and will verify if also keratin-based cell-cell contacts are able to induce mechanical stress responses. Because skin is exposed to different types of straining, uniaxial and biaxial strain signals will be applied using home-built stretching systems. Ultimately, results on monolayer level will be verified on supported multilayered epidermal cell systems by the help of soft-lithography techniques, micromolding and defined surface coating. Tissue stretcher devices will be used in identical experiments also on epidermal skin samples. All experiments will be supported by various constitutive and transient mutant strains to interfere specifically with the different types of adhesion structures. With these experiments we will ultimately aim at char-acterization and understanding of the newly identified cell-cell based mechanosensitivity as vital mechanism that enables every single epidermal cell layer to respond to mechanical stress signals.
DFG Programme
Priority Programmes
