Stephen Revilla '14
Hometown: Knoxville, TN
Senior Study Title: The Role of Cadherin-Based Junctions in the Focal Adhesions of Keratinocytes
Advisor: Dr. Jerilyn Swann
Forces that are translated from the cytoskeleton through the matrix of a cell regulate functions such as cellular spreading, proliferation, and wound healing. The human body responds to injuries by increasing calcium ion concentrations throughout keratinocyte cells, and higher calcium levels can activate cellular components such as E-cadherin, whereas low levels of calcium have been shown to inhibit E-cadherin. Previous studies have shown through Traction Force Microscopy that the force distribution patterns observed in cell colonies vary greatly when E-cadherin functionality is switched on or off. However, the causes for this at the cellular level had not yet been documented. Using fluorescence microscopy, keratinocyte colonies were imaged to view their focal adhesions and compare the distributions of these linking proteins. We found high calcium colonies (with functional E-cadherin) had a significantly denser per unit length ratio of peripheral focal adhesions to inner-colony adhesions than that of low calcium colonies (which lack E-cadherin). The average ratios for high calcium and low calcium colonies were 1.85 to 0.90, respectively. Since focal adhesions display force into the extracellular matrix, and our study showed a distribution of focal adhesions correlating to the force distribution patterns that have been previously shown, this study provides evidence that E-cadherin affects focal adhesion distribution which then influences strain patterns that have been observed in other studies.
Stephen Revilla '14 may not have known it at the time, but the foundation for his Senior Study took shape long before his senior year started.
As an underclassman, he did an on-campus internship in the lab of his advisor, Dr. Jerilyn Swann. The research Revilla worked on during that internship was presented during the 2011 annual meeting of the American Society for Cell Biology in Denver.
"That's where Stephen met the researchers from Yale [University] who recruited him to work with them the following summer," said Swann, chair of the Division of Natural Sciences and associate professor of biology. "I was terribly excited that the work we did here at Maryville College led indirectly to the work he was able to do at Yale."
Swann was confident Revilla would do well during his 10 weeks at Yale because he has, as she puts it, "excellent lab hands."
During his research fellowship at Yale, Revilla worked in the lab of Dr. Valerie Horsley, who studies the "effect of physical forces on cell-cell junctions in skin cells," according to Swann.
Revilla said researching the "mechanobiology of mouse keratinocytes" at Yale was a highlight of his college experience. Keratinocytes, the cells most commonly found in skin, play a vital role in healing wounds.
"I studied the distribution of traction forces created by single cells versus the distribution of forces created by small colonies," he said. "I tried to determine a biological reason for the differences in the force distributions."
Revilla was under pressure at that time because he had only the 10 weeks of his fellowship to collect all the lab data he would need for analysis back at Maryville College.
"I had to ensure that I collected everything of possible use, because collecting more information after returning to Maryville was not an option," he said, pointing out that the research was fascinating to him.
"I decided to study and evaluate the data I had collected and use it to create my senior thesis at Maryville College during the following two years," he said.
Swann said that Revilla's intellectual curiosity served him well throughout the Senior Study process, pointing out that he was thorough and thoughtful in every step of the process, and that he met all of his deadlines, took constructive criticism well and maintained a positive attitude from start to finish.
Revilla, who plans to attend medical school, said he's certain his interest in scientific study has, and will continue to, help him on his way to becoming a physician.
He added that Swann consistently pushed him to do his best work.
"She was there for me every step of the way, spending hours editing my work and advising me on how to improve it," he said. "It was incredible to have an advisor who honestly cared every bit as much as I did about the success of my work."
Swann is confident that Revilla will benefit greatly from the experiences he garnered at Maryville College, especially those from his fellowship at Yale and capstone Senior Study experience.
"As with all Senior Study students, Stephen grew in the knowledge that he has the ability to take on a significant and sustained project, from inception through presentation and defense," Swann said. "What seemed daunting and barely possible was endured and completed successfully. When he has similar obstacles in the future (and he will), he will remember the feeling, trust that it is within his capacity, and tackle it with the same determination and hard work."