Uncovering the role of biochemical ligands in modulating stem cell mechanotransduction and differentiation : a biomaterials-based approach
Abstract/Contents
- Abstract
- The extracellular matrix (ECM) is comprised of different types of proteins and adhesive ligands, which change in composition and ratios during morphogenesis and disease progression. ECM proteins provide cell adhesion and impart mechanical cues to the cells. Increasing substrate stiffness has been shown to trigger Yes-associated protein (YAP) translocation from the cytoplasm to the nucleus, yet the role of ligand parameters in modulating mechanotransduction and stem cell fate remains largely unexplored. Studies of stem cell mechanotransduction and fate have widely used polyacrylamide hydrogels. However, conventional methods of conjugating biochemical ligands to polyacrylamide hydrogels suffer from low efficiency and heterogeneous protein incorporation, making studies of ligand effects on cellular mechanotransduction difficult. Here we report a method that enhances the conjugation of biochemical ligands to polyacrylamide hydrogels, enabling a greater incorporation and tunability of the amount incorporated. Using this method, we studied the effect of ligand density, ligand type, and ligand solvent on modulating cellular mechanotransduction. We showed stiffness-induced YAP translocation occurs only at intermediate ligand densities, whereas at low or high ligand densities, YAP localization is dominated by ligand density independent of substrate stiffness, mediated by cytoskeleton tension and integrin binding. We further showed that, comparing four major ECM proteins: fibronectin, collagen I, collagen IV, and laminin, the density required for such biochemical ligand-induced YAP translocation differs across ECM types. While stiffness-dependent YAP translocation can be induced by all four ECM types, each ECM requires a different optimized ligand density for this to occur. Finally, we assessed the effect of ligand solvent on modulating collagen coatings and downstream cell response. We found that collagen I coatings are highly dependent on solvent pH and composition, with solvents of pH from 3.4 to 8.5 leading to different conjugation efficiencies and distributions. We found that acetic acid of pH 3.4 led to the highest conjugation efficiency and most homogeneous coating, and induced robust MSC spreading and nuclear YAP localization across the broadest range of densities and stiffnesses, as compared to coating solvents such as PBS. The hydrogel platform with enhanced conjugation efficiency of biochemical cues provides a powerful tool for uncovering the role of biochemical cues in regulating mechanotransduction of various stem cell types. Together, results from this work highlight the important role of ligand density, ligand type, and type of ligand solvent as important parameters in studies of mechanotransduction and differentiation, and call for future mechanistic studies to further elucidate the role of changes in ECM compositions in mediating mechanotransduction during morphogenesis and disease progression
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2020; ©2020 |
| Publication date | 2020; 2020 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Stanton, Alice Elizabeth |
|---|---|
| Degree supervisor | Yang, Fan, 1951- |
| Thesis advisor | Yang, Fan, 1951- |
| Thesis advisor | Chaudhuri, Ovijit |
| Thesis advisor | Fordyce, Polly |
| Degree committee member | Chaudhuri, Ovijit |
| Degree committee member | Fordyce, Polly |
| Associated with | Stanford University, Department of Bioengineering. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Alice E. Stanton |
|---|---|
| Note | Submitted to the Department of Bioengineering |
| Thesis | Thesis Ph.D. Stanford University 2020 |
| Location | electronic resource |
Access conditions
- Copyright
- © 2020 by Alice Elizabeth Stanton
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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