Phage-based molecular probes that discriminate force-induced structural states of fibronectin in vivo

• Type of Material: Article
• Authors: Lizhi Cao, Georgia Institute of Technology and Emory University; Mark K. Zeller, Georgia Institute of Technology and Emory University; Vince F. Fiore, Georgia Institute of Technology and Emory University; Patrick Strane, Georgia Institute of Technology and Emory University; Harry Bermudez, University of Massachusetts; Thomas Barker, Emory University
• Language: English
• Date: 2012-05-08
• Publisher: National Academy of Sciences
• Publication Version: Final Published Version
• Copyright Statement: © Cao et al.
• Final Published Version (URL): http://dx.doi.org/10.1073/pnas.1118088109
• Title of Journal or Parent Work: Proceedings of the National Academy of Sciences
• ISSN: 1091-6490
• Volume: 109
• Issue: 19
• Start Page: 7251
• End Page: 7256
• Grant/Funding Information: This work was supported by National Institutes of Health (NIH) T32-GM008433 and NIH T32-EB006343 training grants to L.C., an Armstrong Fund for Science award to H.B., and a Georgia Tech Integrative BioSystems Institute seed grant to T.H.B.
• Keywords: Protein Unfolding; Cells, Cultured; Integrins; Lung; Protein Binding; Microscopy, Confocal; Amino Acid Sequence; Cellular Microenvironment; Peptide Library; Bacteriophages; Mice; Models, Molecular; Protein Structure, Tertiary; Molecular Probes; Fibroblasts; Animals; Extracellular Matrix; Fibronectins; Mechanotransduction, Cellular
• Research Categories: Engineering, Biomedical; Engineering, General

Abstract

Applied forces and the biophysical nature of the cellular microenvironment play a central role in determining cellular behavior. Specifically, forces due to cell contraction are transmitted into structural ECM proteins and these forces are presumed to activate integrin "switches." The mechanism of such switches is thought to be the partial unfolding of integrin-binding domains within fibronectin (Fn). However, integrin switches remain largely hypothetical due to a dearth of evidence for their existence, and relevance, in vivo. By using phage display in combination with the controlled deposition and extension of Fn fibers, we report the discovery of peptidebased molecular probes capable of selectively discriminating Fn fibers under different strain states. Importantly, we show that the probes are functional in both in vitro and ex vivo tissue contexts. The development of such tools represents a critical step in establishing the relevance of theoretical mechanotransduction events within the cellular microenvironment.