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In situ modulation of cell behavior via smart dual-ligand surfaces.

Pulsipher A, Park S, Dutta D, Luo W, Yousaf MN - Langmuir (2014)

Bottom Line: Such tools provide strategies for identifying specific ligand-receptor interactions that induce vital biological consequences.A redox-responsive trigger was incorporated into this surface strategy to spontaneously release ligands in the presence of adhered cells, and cell spreading, growth, and migration responses were measured and compared.The identity and nature of the dual-ligand combination directly influenced cell behavior.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.

ABSTRACT
Due to the highly complex nature of the extracellular matrix (ECM), the design and implementation of dynamic, stimuli-responsive surfaces that present well-defined ligands and serve as model ECM substrates have been of tremendous interest to biomaterials, biosensor, and cell biology communities. Such tools provide strategies for identifying specific ligand-receptor interactions that induce vital biological consequences. Herein, we report a novel dual-ligand-presenting surface methodology that modulates dynamic ECM properties to investigate various cell behaviors. Peptides PHSRN, cRGD, and KKKTTK, which mimic the cell- and heparan sulfate-binding domains of fibronectin, and carbohydrates Gal and Man were combined with cell adhesive RGD to survey possible synergistic or antagonist ligand effects on cell adhesion, spreading, growth, and migration. Soluble molecule and enzymatic inhibition assays were also performed, and the levels of focal adhesion kinase in cells subjected to different ligand combinations were quantified. A redox-responsive trigger was incorporated into this surface strategy to spontaneously release ligands in the presence of adhered cells, and cell spreading, growth, and migration responses were measured and compared. The identity and nature of the dual-ligand combination directly influenced cell behavior.

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Cell behavioral responses to the dynamicrelease of ECM ligands.Cell (A) areas, (B) migration rates, and (C) morphologies after releasing(blue) cRGD, Man, KKKTTK, Gal, or PHSRN from HQ-RGD. Fbs were culturedon the dual ECM ligand-presenting surfaces for 2 h, after which theECM ligands were electrochemically released (PBS, pH 7, 12 cyclicscans: −100 to 850 mV, 100 mV/s) and incubated for an additional2 h. Migration rates were calculated from an 18-h period using live-cellrecording and imaging software after ligand release. Each bar (mean± SEM) represents an average of eight trials (103 cells/mL).
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fig6: Cell behavioral responses to the dynamicrelease of ECM ligands.Cell (A) areas, (B) migration rates, and (C) morphologies after releasing(blue) cRGD, Man, KKKTTK, Gal, or PHSRN from HQ-RGD. Fbs were culturedon the dual ECM ligand-presenting surfaces for 2 h, after which theECM ligands were electrochemically released (PBS, pH 7, 12 cyclicscans: −100 to 850 mV, 100 mV/s) and incubated for an additional2 h. Migration rates were calculated from an 18-h period using live-cellrecording and imaging software after ligand release. Each bar (mean± SEM) represents an average of eight trials (103 cells/mL).

Mentions: The final study in this workconcerned the dynamic release of immobilizedligands in the presence of cells. Fb spreading areas, migration rates,and morphologies were investigated after releasing PHSRN, Gal, Man,KKKTTK, and cRGD from separate HQ-RGD-presenting SAMs. The data arepresented in Figure 6A–C. Remarkably,after ligand release and 4 h adjusted time, the cells more or lessadopted similar phenotypes (Figure 6C), motility(Figure 6B), and spreading areas (Figure 6A) to those of substrates that presented HQ-RGD.The Fbs that were subject to Man, Gal, and PHSRN release reorganizedand extended their actin protrusions, spreading out to adopt similarsizes and migration rates. Similarly, the cells adhered to substratesin which KKKTTK and cRGD were released reorganized their actin cytoskeleton,focal adhesion assemblies, and stress fibers and contracted slightlyto adapt to their new ligand stimulus, HQ-RGD. Thus, these resultsdemonstrate the powerful nature of this surface platform in modulatingthe dynamic ECM environment, where ligands, proteins, and small moleculesare constantly being hidden and revealed to cells.


In situ modulation of cell behavior via smart dual-ligand surfaces.

Pulsipher A, Park S, Dutta D, Luo W, Yousaf MN - Langmuir (2014)

Cell behavioral responses to the dynamicrelease of ECM ligands.Cell (A) areas, (B) migration rates, and (C) morphologies after releasing(blue) cRGD, Man, KKKTTK, Gal, or PHSRN from HQ-RGD. Fbs were culturedon the dual ECM ligand-presenting surfaces for 2 h, after which theECM ligands were electrochemically released (PBS, pH 7, 12 cyclicscans: −100 to 850 mV, 100 mV/s) and incubated for an additional2 h. Migration rates were calculated from an 18-h period using live-cellrecording and imaging software after ligand release. Each bar (mean± SEM) represents an average of eight trials (103 cells/mL).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4334223&req=5

fig6: Cell behavioral responses to the dynamicrelease of ECM ligands.Cell (A) areas, (B) migration rates, and (C) morphologies after releasing(blue) cRGD, Man, KKKTTK, Gal, or PHSRN from HQ-RGD. Fbs were culturedon the dual ECM ligand-presenting surfaces for 2 h, after which theECM ligands were electrochemically released (PBS, pH 7, 12 cyclicscans: −100 to 850 mV, 100 mV/s) and incubated for an additional2 h. Migration rates were calculated from an 18-h period using live-cellrecording and imaging software after ligand release. Each bar (mean± SEM) represents an average of eight trials (103 cells/mL).
Mentions: The final study in this workconcerned the dynamic release of immobilizedligands in the presence of cells. Fb spreading areas, migration rates,and morphologies were investigated after releasing PHSRN, Gal, Man,KKKTTK, and cRGD from separate HQ-RGD-presenting SAMs. The data arepresented in Figure 6A–C. Remarkably,after ligand release and 4 h adjusted time, the cells more or lessadopted similar phenotypes (Figure 6C), motility(Figure 6B), and spreading areas (Figure 6A) to those of substrates that presented HQ-RGD.The Fbs that were subject to Man, Gal, and PHSRN release reorganizedand extended their actin protrusions, spreading out to adopt similarsizes and migration rates. Similarly, the cells adhered to substratesin which KKKTTK and cRGD were released reorganized their actin cytoskeleton,focal adhesion assemblies, and stress fibers and contracted slightlyto adapt to their new ligand stimulus, HQ-RGD. Thus, these resultsdemonstrate the powerful nature of this surface platform in modulatingthe dynamic ECM environment, where ligands, proteins, and small moleculesare constantly being hidden and revealed to cells.

Bottom Line: Such tools provide strategies for identifying specific ligand-receptor interactions that induce vital biological consequences.A redox-responsive trigger was incorporated into this surface strategy to spontaneously release ligands in the presence of adhered cells, and cell spreading, growth, and migration responses were measured and compared.The identity and nature of the dual-ligand combination directly influenced cell behavior.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.

ABSTRACT
Due to the highly complex nature of the extracellular matrix (ECM), the design and implementation of dynamic, stimuli-responsive surfaces that present well-defined ligands and serve as model ECM substrates have been of tremendous interest to biomaterials, biosensor, and cell biology communities. Such tools provide strategies for identifying specific ligand-receptor interactions that induce vital biological consequences. Herein, we report a novel dual-ligand-presenting surface methodology that modulates dynamic ECM properties to investigate various cell behaviors. Peptides PHSRN, cRGD, and KKKTTK, which mimic the cell- and heparan sulfate-binding domains of fibronectin, and carbohydrates Gal and Man were combined with cell adhesive RGD to survey possible synergistic or antagonist ligand effects on cell adhesion, spreading, growth, and migration. Soluble molecule and enzymatic inhibition assays were also performed, and the levels of focal adhesion kinase in cells subjected to different ligand combinations were quantified. A redox-responsive trigger was incorporated into this surface strategy to spontaneously release ligands in the presence of adhered cells, and cell spreading, growth, and migration responses were measured and compared. The identity and nature of the dual-ligand combination directly influenced cell behavior.

Show MeSH
Related in: MedlinePlus