The ability of cells to probe their mechanical environment and react to external stimuli is critical for maintenance of their normal structure and function. Through connections to the extracellular matrix, cells can sense mechanical cues such as substrate rigidity and stretch, and through force transmission across their contractile cytoskeleton can react accordingly to those signals by applying contractile traction forces to their surrounding environment. Healthy cells can react to these mechanical cues to maintain their cytoskeletal prestress (tension) at a set or homeostatic level over time, a phenomenon known as tensional homeostasis. Progression of certain diseases such as asthma, atherosclerosis, and cancer have been linked to a loss of tensional homeostasis. As such, tools for quantifying the traction forces that adhered cells apply to their substrate are crucial for gaining a better understanding of not just how healthy cells interact mechanically with their environment, but also how changes to the extracellular matrix or mutations within the cell can impact their ability to maintain tensional homeostasis and therefore remain both functional and viable. Our group has previously developed a method of quantifying cellular traction forces using indirectly pattered, soft hydrogel substrates known as micropattern traction microscopy. This method was initially developed to create discrete grid micropatterns, which while useful for measuring cellular traction forces does not offer any ability for the user to control cell growth area shape or size. This technique was further improved on through the creation of a protocol for changing discrete grid patterns into isolated island micropatterns, but this two-step process was challenging and generated islands of inconsistent shape and size. Here, we propose a new method for generating isolated island micropatterns of essentially any desired shape and size in a single step, as well as a corresponding image analysis algorithm for calculating cellular traction forces from these island micropatterns.
Additionally, this dissertation also includes an investigation into the impact of distinct Epithelial-cadherin mutations on the ability of gastric adenocarcinoma (AGS) cells to achieve tensional homeostasis. Disruption of tensional homeostasis in the epithelium is a hallmark of certain cancers, and mutations in E-cadherin proteins have been identified in malignant epithelial cells. Here, through analysis of AGS cell traction force data collected previously by Dr. Han Xu during her dissertation work, we have found that two distinct mutations in the intracellular domain of E-cadherins have an impact on the ability of AGS cells to achieve tensional homeostasis.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/48855 |
| Date | 23 May 2024 |
| Creators | Bunde, Katie A. |
| Contributors | Smith, Michael L., Stamenović, Dimitrije |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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