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Modifying Cellular Behavior Through the Control of Insoluble Matrix Cues: The Influence of Microarchitecture, Stiffness, Dimensionality, and Adhesiveness on Cell Function

Hogrebe, Nathaniel James
http://rave.ohiolink.edu/etdc/view?acc_num=osu1470674560

Abstract Details

2016, Doctor of Philosophy, Ohio State University, Biomedical Engineering.
While the soluble biochemical environment has traditionally been viewed as the most important determinant of cell behavior, accumulating evidence indicates that insoluble cues from a cell's surroundings are crucial to a variety of cellular processes. Differences in matrix properties such as stiffness, adhesiveness, and microarchitecture can influence cell shape, cytoskeletal organization, and adhesion formation. These changes can modify enzymatic pathways, control the localization of transcription factors, and even directly modulate gene expression to change overall cell behavior in response to a cell's physical surroundings. While the effects of various insoluble cues have been successfully demonstrated in 2D culture, there has been a lack of fibrous, biomimetic substrates suitable for systematically studying the role of these insoluble cues within a more physiological 3D environment. To this end, we developed and characterized a two component self-assembling peptide (SAP) system that possessed tunable stiffness (controlled via KFE-8 concentration) and RGD binding site density (controlled via KFE-RGD concentration) as well as a fibrous microarchitecture similar to collagen. In contrast to other synthetic 3D matrices such as polyethylene glycol (PEG) or alginate gels which constrict cell spreading, cells encapsulated within these gels were able to adopt non-spherical morphologies similar to those of cells within hydrogels made of natural ECM components. Using this system, we observed that the presence of the RGD binding site was required for both human mesenchymal stem cells (hMSCs) and human umbilical vein endothelial cells (HUVECs) to initially spread within these SAP gels. Furthermore, the extent of this spreading and HUVEC microvascular network (MVN) formation was dictated by stiffness, but each cell type had a different optimal stiffness that was most conducive to these non-spherical morphologies. This culture system was then used to explore the differentiation of hMSCs either encapsulated within or grown on top of SAP gels to determine the interplay of culture dimensionality and stiffness on this differentiation process within a tunable, biomimetic matrix. We demonstrated that in the presence of the same soluble induction factors, culture on top of stiff gels facilitated the most efficient osteogenesis, while encapsulation within the same stiff gels resulted in a switch to predominantly terminal chondrogenesis. Adipogenesis dominated at soft conditions, and 3D culture induced better adipogenic differentiation than 2D culture at a given stiffness. Importantly, initial matrix-induced cell morphology was predictive of these end phenotypes. Furthermore, optimal culture conditions corresponded to each cell type’s natural niche within the body, highlighting the importance of incorporating native matrix dimensionality and stiffness into tissue engineering strategies. As a whole, the work presented here demonstrates that insoluble cues can drastically alter cell behavior and emphasizes the importance of mimicking a cell's native physical environment to optimize cell function. The KFE-8\KFE-RGD SAP system characterized in this work offers a promising alternative to other 3D culture systems for studying the effects of these insoluble cues due to its fibrous, collagen-like microarchitecture as well as its tunable mechanical and adhesive properties. Current work is exploring additional peptide sequences to further streamline this KFE-8\KFE-RGD system for future studies.
Keith Gooch (Advisor)
235 p.
Biomedical Engineering
self-assembling peptide; matrix stiffness; dimensionality; 3D cell culture; microarchitecture; human mesenchymal stem cell differentiation

Recommended Citations

Citations

  • Hogrebe, N. J. (2016). Modifying Cellular Behavior Through the Control of Insoluble Matrix Cues: The Influence of Microarchitecture, Stiffness, Dimensionality, and Adhesiveness on Cell Function [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1470674560

    APA Style (7th edition)

  • Hogrebe, Nathaniel. Modifying Cellular Behavior Through the Control of Insoluble Matrix Cues: The Influence of Microarchitecture, Stiffness, Dimensionality, and Adhesiveness on Cell Function. 2016. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1470674560.

    MLA Style (8th edition)

  • Hogrebe, Nathaniel. "Modifying Cellular Behavior Through the Control of Insoluble Matrix Cues: The Influence of Microarchitecture, Stiffness, Dimensionality, and Adhesiveness on Cell Function." Doctoral dissertation, Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1470674560

    Chicago Manual of Style (17th edition)

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This open access ETD is published by The Ohio State University and OhioLINK.