NF-κB regulation of endothelial cell function during LPS-induced toxemia and cancer
Tatiana Kisseleva, Li Song, Marina Vorontchikhina, Nikki Feirt, Jan Kitajewski, Christian Schindler
Tatiana Kisseleva, Li Song, Marina Vorontchikhina, Nikki Feirt, Jan Kitajewski, Christian Schindler
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Research Article Vascular biology

NF-κB regulation of endothelial cell function during LPS-induced toxemia and cancer

Abstract

The transcription factor NF-κB is an important regulator of homeostatic growth and inflammation. Although gene-targeting studies have revealed important roles for NF-κB, they have been complicated by component redundancy and lethal phenotypes. To examine the role of NF-κB in endothelial tissues, Tie2 promoter/enhancer–IκBαS32A/S36A transgenic mice were generated. These mice grew normally but exhibited enhanced sensitivity to LPS-induced toxemia, notable for an increase in vascular permeability and apoptosis. Moreover, B16-BL6 tumors grew significantly more aggressively in transgenic mice, underscoring a new role for NF-κB in the homeostatic response to cancer. Tumor vasculature in transgenic mice was extensive and disorganized. This correlated with a marked loss in tight junction formation and suggests that NF-κB plays an important role in the maintenance of vascular integrity and response to stress.

Authors

Tatiana Kisseleva, Li Song, Marina Vorontchikhina, Nikki Feirt, Jan Kitajewski, Christian Schindler

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Figure 3

Transgenic ECs exhibit enhanced apoptosis.

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Transgenic ECs exhibit enhanced apoptosis. (A) Frozen hepatic tissue sec...
(A) Frozen hepatic tissue sections prepared from WT and Tie-Tg (line 2) mice 18 hours after PBS or LPS (2 μg/g weight) injection, stained for PECAM-1 and caspase-3 (anti–active caspase-3–specific antibody) and then visualized under a ×20 objective. Similar results were obtained with Tie–Tg line 4. (B) Immunostaining revealed a defect in the nuclear translocation of p65 in TNF-α–stimulated (100 ng/ml, 1 hour) cultured primary, pulmonary transgenic ECs. Phase-contrast bright-field (BF) images (×100 objective) of the same cells are shown in the upper panels. ECs were prepared from WT and Tie-Tg lines 2 and 4. (C) Cultured primary transgenic ECs exhibit enhanced nuclear fragmentation after TNF-α (100 ng/ml, 4.5 hours) stimulation, as revealed by DAPI staining (lower panels). Phase-contrast bright-field images (×100 objective) of the same cells are shown in the upper panels. (D) Quantification of the nuclear fragmentation/apoptosis data presented in C. Analysis represents the percentage of cells exhibiting clear nuclear fragmentation in 5 independent fields of 100 cells. Evaluation was performed by a researcher blinded to the experimental protocol.