Infection of endothelial cells with Trypanosoma cruzi activates NF-kappa Band induces vascular adhesion molecule expression

Transcriptional activation of vascular adhesion molecule expression, a majo r component of on inflammatory response, is regulated, in part, by the nucl ear factor-kappa B/Rel (NF-kappa B) family of transcription factors. We the refore determined whether Trypanosoma cruzi infection of endothelial cells resulted in the activation of NF-kappa B and the induction or increased exp ression of adhesion molecules. Human umbilical vein endothelial cells (HUVE C) were infected with trypomastigotes of the Tulahuen strain of T. cruzi. E lectrophoretic mobility shift assays with an NF-kappa B-specific oligonucle otide and nuclear extracts from T. cruzi-infected HUVEC (6 to 48 h postinfe ction) detected two major shifted complexes. Pretreatment with 50x cold NF- kappa B consensus sequence abolished both gel-shifted complexes while exces s SP-I consensus sequence had no effect. These data indicate that nuclear e xtracts from T. cruzi-infected HUVEC specifically hound to the NF-kappa B c onsensus DNA sequence. Supershift analysis revealed that the gel-shifted co mplexes were comprised of p65 (RelA) and p50 (NF-kappa B1). Northern blot a nalyses demonstrated both the induction of vascular cell adhesion molecule 1 and E-selectin and the upregulation of intercellular adhesion molecule 1 mRNA in HUVEC infected with T. cruzi. Immunocytochemical staining confirmed adhesion molecule expression in response to T. cruzi infection. These find ings are consistent with the hypothesis that the activation of the NF-kappa B pathway in endothelial cells associated with T. cruzi infection may be a n important factor in the inflammatory response and subsequent vascular inj ury and endothelial dysfunction that lead to chronic cardiomyopathy.