Figure 5: Nuclear S100A9 protein promotes NFI-A expression in Gr1⁺CD11b⁺ cells during late sepsis.

Gr1⁺CD11b⁺ cells were isolated from the bone marrow of sham and septic mice. S100A9 or NFI-A protein levels were determined by western blot. (A) Levels of S100A9 protein in the nucleus and cytosol of Gr1⁺CD11b⁺ cells from wild-type mice. (B) Levels of S100A9 proteins in the nucleus and cytosol of Gr1⁺CD11b⁺ cells from S100A9 knockout mice. The cells were isolated during the late sepsis phase (days 6–28 after sepsis induction) and transfected with S100A9 expression plasmid for 36 hr and then stimulated with 10 ng/ml of recombinant murine IL-10 for 6 hr. Cells were pooled from 2 mice per group. (C) Levels of NFI-A protein in Gr1⁺CD11b⁺ cells from wild-type mice. (D) Levels of NFI-A proteins in Gr1⁺CD11b⁺ cells from S100A9 knockout mice. The cells were isolated during the late sepsis phase and transfected and treated as in A. Cells from sham and sepsis mice, and without transfection were used as controls. Cells were pooled from 2 mice per group. The results are representative of three independent experiments. KO, knockout.