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Toxoplasma Gondii Invasion of Host Cells with Altered Cytoskeleton According to Substrate Stiffness

Presenters Name: 
Grace Gallagher
Primary Research Mentor: 
Brian Helmke
Secondary Research Mentor: 
10:00 - 10:15
Time of Presentation: 
2019 - 10:15am to 10:30am
Commonwealth Room
Presentation Type: 
Presentations Academic Category: 
Grant Program Recipient: 
USOAR Program

Toxoplasmosis, a disease caused by Toxoplasma gondii, affects about a third of Americans and can be harmful to people with immunodeficiencies. The parasite, Toxoplasma gondii has strange characteristics including its invasion of host, epithelial cells. Many mechanical and biochemical factors play a part in the microorganism’s invasion and proliferation, yet little is known about the specifics of mechanochemical interactions. My research question asks how the balance of forces between the host cell’s cytoskeleton and the parasite’s generated force influences the rate of invasion of Toxoplasma gondii. By manipulating the stiffness of host cells, the balance of these forces would shift. Previous research has shown that a cell’s cytoskeleton tension depends on the stiffness of a substrate, so a host cell’s cytoskeleton should change according to the substrate it grows on. Because the softer gel substrates do not provide the same levels of structure to the cells, the balance between host cell cytoskeleton and invading parasites is reduced on the softer gels and is expected to lead to limited invasion. Using fibroblasts as model cells for parasitic invasion, I plated fibroblasts on polyacrylamide gels with varying stiffness and measured cytoskeleton organization and Toxoplasma’s rate of invasion for each gel. With fluorescent staining and microscopy, the cytoskeleton’s structures were visibly different between the gels, and the rates of invasion are expected to vary also. This balance of forces could be further studied to gain knowledge of how or why the microorganism generates force and provide treatment and preventative options if further explored.