title: Effects of substrate stiffness on cell morphology, cytoskeletal structure, and adhesion.
abstract: The morphology and cytoskeletal structure of fibroblasts, endothelial cells, and neutrophils are documented for cells cultured on surfaces with stiffness ranging from 2 to 55,000 Pa that have been laminated with fibronectin or collagen as adhesive ligand. When grown in sparse culture with no cell-cell contacts, fibroblasts and endothelial cells show an abrupt change in spread area that occurs at a stiffness range around 3,000 Pa. No actin stress fibers are seen in fibroblasts on soft surfaces, and the appearance of stress fibers is abrupt and complete at a stiffness range coincident with that at which they spread. Upregulation of alpha5 integrin also occurs in the same stiffness range, but exogenous expression of alpha5 integrin is not sufficient to cause cell spreading on soft surfaces. Neutrophils, in contrast, show no dependence of either resting shape or ability to spread after activation when cultured on surfaces as soft as 2 Pa compared to glass. The shape and cytoskeletal differences evident in single cells on soft compared to hard substrates are eliminated when fibroblasts or endothelial cells make cell-cell contact. These results support the hypothesis that mechanical factors impact different cell types in fundamentally different ways, and can trigger specific changes similar to those stimulated by soluble ligands.
authors.affiliation: Institute for Medicine and Engineering, University of Pennsylvania, PA 19104, USA.
authors.forename: Tony
authors.initials: T
authors.lastname: Yeung
authors.forename: Penelope C
authors.initials: PC
authors.lastname: Georges
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Flanagan
authors.forename: Beatrice
authors.initials: B
authors.lastname: Marg
authors.forename: Miguelina
authors.initials: M
authors.lastname: Ortiz
authors.forename: Makoto
authors.initials: M
authors.lastname: Funaki
authors.forename: Nastaran
authors.initials: N
authors.lastname: Zahir
authors.forename: Wenyu
authors.initials: W
authors.lastname: Ming
authors.forename: Valerie
authors.initials: V
authors.lastname: Weaver
authors.forename: Paul A
authors.initials: PA
authors.lastname: Janmey
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D001011:Aorta / Q000166:cytology; D002417:Cattle; D002448:Cell Adhesion; D002460:Cell Line; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology* / Q000502:physiology; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology* / Q000502:physiology; D005353:Fibronectins / Q000378:metabolism; D005898:Glass; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D039482:Integrin alpha5 / Q000378:metabolism; D051379:Mice; D018613:Microscopy, Confocal; D041681:NIH 3T3 Cells; D009504:Neutrophils / Q000166:cytology* / Q000502:physiology; D022502:Stress Fibers; D013499:Surface Properties
chemical_list: D000199:Actins; D005353:Fibronectins; D039482:Integrin alpha5; D049452:Green Fluorescent Proteins; D003094:Collagen