Barrett, The Honors College at Arizona State University proudly showcases the work of undergraduate honors students by sharing this collection exclusively with the ASU community.

Barrett accepts high performing, academically engaged undergraduate students and works with them in collaboration with all of the other academic units at Arizona State University. All Barrett students complete a thesis or creative project which is an opportunity to explore an intellectual interest and produce an original piece of scholarly research. The thesis or creative project is supervised and defended in front of a faculty committee. Students are able to engage with professors who are nationally recognized in their fields and committed to working with honors students. Completing a Barrett thesis or creative project is an opportunity for undergraduate honors students to contribute to the ASU academic community in a meaningful way.

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Description
Cellular and molecular biologists often perform cellular assays to obtain a better understanding of how cells work. However, in order to obtain a measurable response by the end of an experiment, the cells must reach an ideal cell confluency. Prior to conducting the cellular assays, range-finding experiments need to be

Cellular and molecular biologists often perform cellular assays to obtain a better understanding of how cells work. However, in order to obtain a measurable response by the end of an experiment, the cells must reach an ideal cell confluency. Prior to conducting the cellular assays, range-finding experiments need to be conducted to determine an initial plating density that will result in this ideal confluency, which can be costly. To help alleviate this common issue, a mathematical model was developed that describes the dynamics of the cell population used in these experiments. To develop the model, images of cells from different three-day experiments were analyzed in Photoshop®, giving a measure of cell count and confluency (the percentage of surface area covered by cells). The cell count data were then fitted into an exponential growth model and were correlated to the cell confluency to obtain a relationship between the two. The resulting mathematical model was then evaluated with data from an independent experiment. Overall, the exponential growth model provided a reasonable and robust prediction of the cell confluency, though improvements to the model can be made with a larger dataset. The approach used to develop this model can be adapted to generate similar models of different cell-lines, which will reduce the number of preliminary range-finding experiments. Reducing the number of these preliminary experiments can save valuable time and experimental resources needed to conduct studies using cellular assays.
ContributorsGuerrero, Victor Dominick (Co-author) / Guerrero, Victor (Co-author) / Watanabe, Karen (Thesis director) / Jurutka, Peter (Committee member) / School of Mathematical and Natural Sciences (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
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Description
The retinoid-X receptor (RXR) can form heterodimers with both the retinoic-acid
receptor (RAR) and vitamin D receptor (VDR). The RXR/RAR dimer is activated by ligand all
trans retinoic acid (ATRA), which culminates in gut-specific effector T cell migration. Similarly,
the VDR/RXR dimer binds 1,25(OH)2D3 to cause skin-specific effector T cell migration.

The retinoid-X receptor (RXR) can form heterodimers with both the retinoic-acid
receptor (RAR) and vitamin D receptor (VDR). The RXR/RAR dimer is activated by ligand all
trans retinoic acid (ATRA), which culminates in gut-specific effector T cell migration. Similarly,
the VDR/RXR dimer binds 1,25(OH)2D3 to cause skin-specific effector T cell migration.
Targeted migration is a potent addition to current vaccines, as it would induce activated T cell
trafficking to appropriate areas of the immune system and ensure optimal stimulation (40).
ATRA, while in use clinically, is limited by toxicity and chemical instability. Rexinoids
are stable, synthetically developed ligands specific for the RXR. We have previously shown that
select rexinoids can enhance upregulation of gut tropic CCR9 receptors on effector T cells.
However, it is important to establish whether these cells can actually migrate, to show the
potential of rexinoids as vaccine adjuvants that can cause gut specific T cell migration.
Additionally, since the RXR is a major contributor to VDR-mediated transcription and
epidermotropism (15), it is worth investigating whether these compounds can also function as
adjuvants that promote migration by increasing expression of skin tropic CCR10 receptors on T
cells.
Prior experiments have demonstrated that select rexinoids can induce gut tropic migration
of CD8+ T cells in an in vitro assay and are comparable in effectiveness to ATRA (7). The effect
of rexinoids on CD4+ T cells is unknown however, so the aim of this project was to determine if
rexinoids can cause gut tropic migration in CD4+ T cells to a similar extent. A secondary aim
was to investigate whether varying concentrations in 1,25-Dihydroxyvitamin D3 can be linked to
increasing CCR10 upregulation on Jurkat CD4+ T cells, with the future aim to combine 1,25
Dihydroxyvitamin D3 with rexinoids.
These hypotheses were tested using murine splenocytes for the migration experiment, and
human Jurkat CD4+ T cells for the vitamin D experiment. Migration was assessed using a
Transwell chemotaxis assay. Our findings support the potential of rexinoids as compounds
capable of causing gut-tropic migration in murine CD4+ T cells in vitro, like ATRA. We did not
observe conclusive evidence that vitamin D3 causes upregulated CCR10 expression, but this
experiment must be repeated with a human primary T cell line.
ContributorsDebray, Hannah Zara (Co-author) / Debray, Hannah (Co-author) / Blattman, Joseph (Thesis director) / Jurutka, Peter (Committee member) / Manhas, Kavita (Committee member) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05