Fig. 4

Loss of Cdc50 led to decreased phagocytosis rate in macrophages and increased pro-inflammatory cytokine secretion. A Aliquots of THP-1 cells were co-incubated with wild-type (WT), Δcdc50, and Δcdc50 + CDC50 yeast for 2 h, then washed and lysed to release intracellular yeast for CFU counting. Other THP-1 cells were cultured for another 4 h after the 2-h co-incubation and washing, and lysed for CFU counting. After being exposed to macrophages for 2 h, the Δcdc50 mutant exhibited a much lower phagocytosis rate compared with the WT and Δcdc50 + CDC50 strains. Accordingly, the number of surviving intracellular Δcdc50 yeast were reduced by almost 50% compared with that of the surviving WT yeasts after 6 h. B After a 2-h co-incubation with yeast cells, THP-1 cells were brushed and Gram stained to count the intracellular yeast. The Δcdc50 cells were about 58.6% of WT cells, exhibiting less uptake by macrophages. C Typical field views of THP-1 after co-incubation with WT and Δcdc50 cells, respectively. D Different C. glabrata strains were co-incubated with THP-1 cells for 4 h, and the culture supernatants were collected and centrifugated to measure the secreted TNF-α and IL-1β levels. THP-1 cells without exposure to yeast were used for baseline secretion level estimation as a negative control. Exposure to WT and Δcdc50 + CDC50 hardly triggered enhanced secretion of pro-inflammatory cytokines in macrophages, whereas the loss of Cdc50 activity in C. glabrata caused increased secretion of TNF-α and IL-1β. Data represent the mean ± SD of three independent experiments. NC Negative control. *, P < 0.05; **, P < 0.01