Figure 5.

Regulation of barrier function by APE1 A) Compromised barrier function in T84 cells was assayed by TEER and found to be reduced with lower MOI of S. Typhimurium after 3 h (3-4 replicates). (B) Infection (MOI 10) for 5 h of T84 cells on transwell inserts with wild type or mutants (ΔSPI-1 or ΔSPI-2) of S. Typhimurium resulted in barrier loss by S. Typhimurium that expressed SPI-1 (wild type or ΔSPI-2) but not when SPI-1 (ΔSPI-1) was lacking as shown from four to five replicates. (C) To confirm the impact of the number of intracellular bacteria on barrier recovery, T84 cells were infected at MOI 10 in triplicate and treated with a cell impermeable antibiotic gentamicin, or the cell permeable antibiotics chloramphenicol or ciprofloxacin. Cell permeable antibiotic treatment resulted in improved barrier recovery and have reduced numbers of intracellular bacteria (latter data not shown). (D) Following infection (MOI 10) or treatment with glucose oxidase, cells were washed and cell culture medium containing gentamicin was added. Barrier recovery was recorded the next day. Data show that APE1-deficient cells infected with S. Typhimurium had reduced recovery compared to cells with similar loss in barrier induced by glucose oxidase. Data shown are from three independent experiments. All error bars are represented as SEM. *p < 0.05; **p < 0.01; ***p < 0.001.