Effect of Candida albicans infection on the plasma membrane expression of the Na+-K+-2Cl– cotransporter 1 (NKCC1) in T84 and Madin Darby Canine Kidney cells (MDCK)

Abstract

C. albicans is a commensal human fungal pathogens. To infect the human body, it must penetrate the intestinal mucosal barrier. Fluid secretion is one of the intestinal defense mechanisms and NKCC1 is a key protein regulating fluid secretion in the colon. We hypothesize that, C. albicans, before invasion decreases fluid secretion by causing NKCC1 internalization. In our experiments, we used MDCK cells expressing a GFP-NKCC1, and T84 a human colonic. Cells were infected with 100,000 C. albicans for different times, fixed, stained and mounted for fluorescence microscopy. Images were acquired using an Olympus IX83 microscope equipped with a DP80 CCD camera. The number of vesicles was evaluated using FIJI. Our preliminary results show that in MDCK cells, phorbol 12 myristate 13 acetate (PMA), a positive control, induced a significant increase of vesicles containing NKCC1 (P\u3c0.001), whereas C. albicans did not significantly increase NKCC1 internalization at all time points tested (ANOVA, Dunnett\u27s Multiple Comparison). Similarly, PMA induced a significant increase of NKCC1 internalization (P=0.007) in T84 Cells. Infecting T84 cells with C. albicans, significantly induced NKCC1 internalization only at 90 min (P=0.01), but not at other time points. Our results suggest that C. albicans causes internalization of NKCC1 which would decrease fluid secretion. The non-significance at some time points may be due to the low number of replicates at our early time points, whereas at later time points we suspect that NKCC1 is already degraded and cannot be detected