Date of Award

2015

Document Type

Open Access Thesis

Department

Biomedical Science

First Advisor

Jay Potts

Abstract

Epithelial cells, as well as other differentiated cell types, remodel surrounding collagen in vitro, to self organize into 3D structures. When placed on-top or inside of a collagen hydrogel, cells organize into a toroid or spheroid form. It is not clearly understood how these cell types modulate surrounding collagen to form 3D shapes. The goal of this project was to determine if cell type, collagen type, or cell placement are factors that can alter how cells reorganize and remodel collagen hydrogels. We hypothesize that the positioning, cell type and the type of collagen they are in contact with affect the 3D reorganization of cells in collagen. Staining the cell nuclei, the actin cytoskeleton and monitoring cell proliferation provided better insight as to how cells organize over time in collagen hydrogels. Alpha smooth muscle actin and vimentin proteins were targeted to identify the shapes of cells in the hydrogels. Hydrogel thickness measurements and cell alignment studies were done to monitor the modulation of collagen over time and determine if patterns of cellular organization were present throughout the hydrogel. When placed on-top of a collagen hydrogel, rat neonatal heart fibroblasts (rat NHFC) modulated type I and type III collagen hydrogels into toroidal forms. Rat tail collagen hydrogels shrank when rat NHFCs were interspersed inside. However, unlike other inside placed cellular hydrogels, rat NHFC placed inside of a human type III collagen hydrogels developed ring shaped cellular alignments around the edges of the hydrogel. Rat NHFCs can modulate human type III collagen in a different manner than that with rat tail collagen. Unlike the rat NHFC, the mouse breast cancer cell line 4TI-LUC did not form toroids or remodel collagen when placed on top or inside of a collagen hydrogel. Cancer inhibits the migration and reorganization processes observed in non-cancerous cell types. Hence, there seems to be a universal process involved when non-cancerous cells interact with a collagen hydrogel when placed on the surface.

Rights

© 2015, Chad Simmons

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