LPS may activate cytokines in TI cells via the NF-kB/IκB pathway.

<p>A. <u>LPS stimulates IKKα/β expression in TI cells</u>. Cytocentrifuged mixed cell preparations from LPS-treated (10 µg/ml) TI cells were double-stained with an antibody to phospho-IKKα/β and RTI40, a TI cell marker. A, D, G) Mixed lung cell preparation stained with phospho-IKKα/β at various timepoints after LPS stimulation, demonstrating decreasing staining intensity of phospho-IKKα/β over time; B, E, H) cells stained with RTI40 to display TI cells; C, F, I) merged images demonstrating colocalization of phospho-IKKα/β and a TI cell-specific marker. J) Control image showing lack of staining in the absence of a specific primary antibody; K) phase contrast image of the control slide. Image magnification is 40×. B. <u>LPS induces NF-κB transcript in cultured TI cells</u>. Expression of NF-κB transcript in cultured TI cells increased after LPS stimulation (LPS 10 µg/ml). Relative to the amount of transcript found in TI cells at baseline (n = 4), LPS injury increased NF-κB levels by 9-fold in TI cells (n = 4, *p<0.05). LPS also increased NF-κB transcripts 8-fold in TII cells (n = 5) over TII controls (n = 5, ** p<0.05). Data is expressed as fold expression of NF-κB mRNA over control ± SEM and all values were normalized to 18S.