title: Directing epithelial to mesenchymal transition through engineered microenvironments displaying orthogonal adhesive and mechanical cues.
abstract: Cell interactions with their extracellular matrix (ECM) microenvironments play a major role in directing cellular processes that can drive wound healing and tissue regeneration but, if uncontrolled, lead to pathological progression. One such process, epithelial to mesenchymal transition (EMT), if finely controlled could have significant potential in regenerative medicine approaches. Despite recent findings that highlight the influence of biochemical and mechanical properties of the ECM on EMT, it is still unclear how these two orthogonal cues act synergistically to control epithelial cell phenotype. Here, we cultured lung epithelial cells on combinations of different mutants of fibronectin's cell binding domain that preferentially engage specific integrins and substrates of varying stiffness. Our results suggest that while stiff substrates induce spontaneous EMT, this response can be overcome by with fragments of fibronectin that support α3 and α5 integrin engagement. Furthermore, we found that substrate-induced EMT correlates with transforming growth factor beta activation by resident epithelial cells and is dependent on Rho/ROCK signaling. Suppressing cell-contractility was sufficient to maintain an epithelial phenotype. Our results suggest that integrin-specific engagement of fibronectin adhesive domains and the mechanics of the ECM act synergistically to direct EMT.
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, USA.
authors.forename: Marilyn C
authors.initials: MC
authors.lastname: Markowski
authors.forename: Ashley C
authors.initials: AC
authors.lastname: Brown
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Barker
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D060833:Cellular Microenvironment / Q000187:drug effects; D003463:Cues; D004847:Epithelial Cells / Q000166:cytology*; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects; D005353:Fibronectins / Q000737:chemistry / Q000494:pharmacology; D008907:Mink; D010641:Phenotype; D055550:Protein Stability / Q000187:drug effects; D011650:Pulmonary Alveoli / Q000166:cytology; D020449:Repetitive Sequences, Amino Acid; D016212:Transforming Growth Factor beta / Q000494:pharmacology
chemical_list: D015415:Biomarkers; D005353:Fibronectins; D016212:Transforming Growth Factor beta