title: Tuning cell-surface affinity to direct cell specific responses to patterned proteins.
abstract: Interactions with local extracellular cues direct cell migration. A versatile method to study cell response to a protein consists of patterning the protein cue on a substrate and quantifying the distribution of cells between patterned and non-patterned areas. Here, we define the concepts of (i) cell-surface affinity to describe cell choices, and of (ii) reference surface (RS) to clarify that the choice is made relative to a reference. Furthermore, we report a method to systematically tune the RS and show that it can dominate the experimental cell response to a protein cue. The cell response to a cue can be switched from strong preference to strong aversion by only changing the RS. Using microcontact printing, we patterned the extracellular matrix proteins fibronectin or netrin-1 adjacent to a series of RSs with different ratios of poly-D-lysine (PDL) and polyethylene glycol (PEG), which are of high affinity and of low-affinity for cells, respectively. C2C12 myoblasts or primary neurons seeded on substrates with a high affinity RS (high % PDL) did not respond to a printed protein of interest, and conversely on RSs of low affinity (high % PEG) the cells preferred the printed protein even in the absence of a specific interaction. However, when testing cell response to a standardized series of RSs varying from high to low affinity, a specific response curve was obtained that was unique to each cell type-protein pair. Importantly, for intermediate RSs with moderate affinity, the cell response to the cue was dependent on the activation of biologically relevant protein-specific biochemical signal transduction pathways. Our results establish that choices made by cells in response to a surface-bound cue must take into account, and be interpreted in the context of, the RS. The use of a series of RSs with varying cell-surface affinity reveals specific response curves of cells to a cue that can be compared quantitatively and that may help gain new insights into cellular responses to extracellular proteins.
authors.affiliation: McGill Program in NeuroEngineering, Department of Biomedical Engineering, McGill University, 740 Dr. Penfield Avenue, Montreal, Quebec H3A 0G1, Canada; Genome Quebec Innovation Centre, McGill University, Montréal, Quebec H3A 0G1, Canada; McGill Program in NeuroEngineering, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Ave., Montreal, Quebec H3A 2B4, Canada.
authors.forename: Sébastien G
authors.initials: SG
authors.lastname: Ricoult
authors.forename: Greta
authors.initials: G
authors.lastname: Thompson-Steckel
authors.forename: James P
authors.initials: JP
authors.lastname: Correia
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Kennedy
authors.forename: David
authors.initials: D
authors.lastname: Juncker
mesh_terms: D000818:Animals; D002448:Cell Adhesion; D002460:Cell Line; D002462:Cell Membrane; D002465:Cell Movement; D016326:Extracellular Matrix Proteins / Q000737:chemistry*; D005347:Fibroblasts / Q000166:cytology; D005353:Fibronectins / Q000737:chemistry*; D051379:Mice; D032446:Myoblasts / Q000166:cytology; D009414:Nerve Growth Factors / Q000737:chemistry*; D000075388:Netrin-1; D009474:Neurons / Q000166:cytology; D011092:Polyethylene Glycols / Q000737:chemistry; D011107:Polylysine / Q000737:chemistry; D051381:Rats; D015398:Signal Transduction; D013499:Surface Properties; D025521:Tumor Suppressor Proteins / Q000737:chemistry*
chemical_list: D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D009414:Nerve Growth Factors; C000617353:Ntn1 protein, mouse; C000617354:Ntn1 protein, rat; D025521:Tumor Suppressor Proteins; D000075388:Netrin-1; D011107:Polylysine; D011092:Polyethylene Glycols
keywords: Cell–surface affinity; Fibronectin; Microcontact printing; PDL; PDMS; PLL-g-PEG; Poly(ethylene glycol); Polylysine; Reference surface; poly-d-lysine; poly-l-lysine-grafted-polyethylene glycol; polydimethylsiloxane