Level of Education of Students Involved

Undergraduate

Faculty Sponsor

patrice Bouyer

College

Arts and Sciences

Discipline(s)

Biology

Presentation Type

Oral Presentation

Symposium Date

Spring 4-27-2023

Abstract

The commensal human fungal pathogen, Candida albicans, prior to infect the human body, must penetrate the intestinal mucosal barrier. To do so, it needs to bypass the different protective mechanisms such as fluid secretion. The basolateral Na+-K+-2Cl– cotransporter 1 (NKCC1) is a key protein regulating fluid secretion in the intestine. We hypothesize that C. albicans decreases fluid secretion prior to invasion by inducing NKCC1 internalization. In our experiments, we used Madin Darby canine kidney (MDCK) cells expressing a GFP-NKCC1 fluorescent tag and T84 cells, a human colonic cell line. Cells were infected with 100,000 C. albicans for varying lengths of time, fixed, stained and mounted for fluorescence microscopy. The number of internalized vesicles was evaluated using FIJI. Our results show that in MDCK cells, C. albicans only increased NKCC1 internalization at the 30-minute time point (P<0.05), all subsequent time points were not significant. Similarly, infecting T84 cells with C. albicans significantly induced NKCC1 internalization at the 30-minute (P<0.05), 1 hour (P<0.05), and 90-minute (P<0.05) time points. Past 90 minutes, we observed a sharp decline in the number of internalized vesicles that continued to decrease through 6 hours of exposure to C. albicans. Finally, in C. albicans-T84 infected cells, using an immunoblot approach, we found that total NKCC1 protein expression was decreased by ~20% (P<0.05) compared to uninfected cells. Our results suggest that C. albicans induces internalization of NKCC1, and subsequent degradation of NKCC1, which would decrease fluid secretion and allow adhesion, and invasion of the epithelium.

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