Investigating macrophage interactions with Listeria monocytogenes grown at different temperatures with or without propionate

Investigating macrophage interactions with Listeria monocytogenes grown at different temperatures with or without propionate

Presenter(s)

Patrick Hurst

Comments

1:40-2:00, Kennedy Union 211

Description

Listeria monocytogenes is a Gram-positive, intracellular pathogen responsible for the deadly foodborne illness listeriosis. L. monocytogenes expresses different virulence factors in response to different environmental factors, influencing how L. monocytogenes interacts with the host immune system. One of the first immune defenses that L. monocytogenes encounters in the body is the phagocytic macrophage. Macrophages can exhibit different shapes or antimicrobial functions depending on the activation state (M1 vs M2). It is currently unclear how the environment in which L. monocytogenes is grown affects the functions of infected macrophage. We hypothesize that macrophage can distinguish between L. monocytogenes grown in 0 degrees C conditions and 37 degrees C conditions, with and without the presence of the short-chain fatty acid propionate, and respond accordingly. This hypothesis was tested by exposing naïve or M1-activated macrophages to L. monocytogenes grown under these different conditions, and quantifying outputs indicative of macrophage activity. Macrophage outputs that were measured included nitric oxide (NO) production using a standard colorimetric assay and cell morphology using an image analysis software (Image J). Propionate pre-treatment or different growth temperatures in L. monocytogenes did not cause a significant difference in NO production by the infected macrophages. However, NO productions were significantly higher in activated macrophages infected by L. monocytogenes grown at 0C with propionate and 37C without propionate, compared to infected native macrophages. Circularity values of infected macrophages at 24 hours post infection were also compared. These results showed that while temperature and propionate independently did not impact macrophage responses, they could have a synergistic effect when combined. Further investigations are needed to dissect the specific mechanisms.

Publication Date

4-23-2025

Project Designation

Honors Thesis

Primary Advisor

Yvonne Y. Sun

Primary Advisor's Department

Biology

Keywords

Stander Symposium, College of Arts and Sciences

Institutional Learning Goals

Scholarship

Investigating macrophage interactions with Listeria monocytogenes grown at different temperatures with or without propionate

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