Date of Defense

4-16-2024

Date of Graduation

4-2024

Department

Biological Sciences

First Advisor

Wendy Beane

Second Advisor

Samantha Hack

Third Advisor

Andrew Thompson

Abstract

Apoptosis is controlled cell death involved in the homeostasis of the stem cells. Too much apoptosis can lead to neurodegenerative diseases and too little can lead to cancer. A family of caspase proteins, also known as cysteine proteases, are involved in the activation of apoptosis. Caspases can be activated extrinsically or intrinsically, and caspases-3 and -8 specifically activate apoptosis via extrinsic mechanisms. The ways in which caspase-3 or -8 are activated or inhibited are unknown, and if they change the amount of apoptosis that occurs. The inhibition of caspase-3 and/or -8 leads to a decrease in apoptosis. Highly regenerative planarian flatworms, Schmidtea mediterranea. are an ideal model system to investigate regeneration signaling pathways. Planarians have a large amount of stem cell population, can regenerate in a short period of time, and have similar genes to vertebrates, which makes this data applicable to humans in the future. Utilizing the double stranded RNA interference (dsRNA) feeding protocol should show a decrease in the blastema size, which demonstrates a decrease in apoptosis. Also, an immunology test that utilizes drug exposure before using a primary and secondary antibody to illuminate the interested cells, this will show inhibition of apoptosis if there are a smaller number of apoptotic cells appear afterwards. We found that Caspase 8 inhibits apoptosis through dsRNA feeding because it showed a smaller blastema size. Also, apoptosis was inhibited with the exposure of the M50054 drug and the anti-active caspase-3 primary antibody. A better way to visualize caspase-3 expression with planarians was also determined. A new antibody was tested during the immunology test to validate it would work to label caspase-3. These findings improve our understanding of the mechanisms that control apoptosis during regeneration. Being able to control apoptosis could be important for researching and treating diseases such as cancer and neurodegenerative diseases.

Access Setting

Honors Thesis-Restricted

Restricted to Campus until

6-19-2026

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Available for download on Friday, June 19, 2026

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