Thu, 24 Jul 2008 23:15:53 BST CiteULike: AlfonsoVicenteSuarezs flagellin-biphasic http://www.citeulike.org/user/AlfonsoVicenteSuarez/tag/flagellin-biphasic CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/AlfonsoVicenteSuarez/article/1642454 <i>Biochemical and Biophysical Research Communications, Vol. 355, No. 1. (30 March 2007), pp. 280-285.</i><br /><br />Bacterial flagellin is recognized by Toll-like receptor (TLR5) and activates NF-[kappa]B which leads to the induction of proinflammatory gene expression. Salmonella expresses two flagellin proteins, FliC and FljB. We purified FliC and FljB and examined the ability of the Salmonella flagellins to activate the NF-[kappa]B transcription factor in human embryonic kidney cells. We found that FliC and FljB as purified proteins possessed a comparable specific activity for activation of NF-[kappa]B-dependent gene expression in HEK293 cells. We also determined the ability of UV-inactivated bacteria, both wild-type and fliC and fljB mutant strains, to activate NF-[kappa]B. Wild-type fliC+/fljB+ Salmonella and the fliC+/fljB- mutant strain were robust activators, whereas the fliC-/fljB+ and flhC- mutant strains were very poor activators. The NF-[kappa]B activation capacity of bacterial strains correlated with their flagellin expression level. Finally, Salmonella cell wall-associated polymeric flagellin displayed greatly reduced ability to activate NF-[kappa]B compared to purified monomeric flagellin. Activation of NF-[kappa]B-dependent gene expression by Salmonella flagellins FliC and FljB Raphael Simon Charles Samuel doi:10.1016/j.bbrc.2007.01.148 Biochemical and Biophysical Research Communications, Vol. 355, No. 1. (30 March 2007), pp. 280-285. 2007-09-10T16:00:02-00:00 2007 Biochemical and Biophysical Research Communications 355 1 280 285 flagellin-biphasic http://www.citeulike.org/user/AlfonsoVicenteSuarez/article/1642416 <i>J. Clin. Invest., Vol. 107, No. 1. (1 January 2001), pp. 99-109.</i><br /><br />This study investigated whether soluble paracrine factors mediated Salmonella-induced IL-8 expression in polarized model intestinal epithelia. We found that the basolateral media of model epithelia that had been apically infected with Salmonella typhimurium for a short period (10 minutes) could activate IL-8 secretion in virgin model epithelia, demonstrating that a proinflammatory factor (PIF) was indeed present. Initial characterization found that PIF was a heat-stable protein with a molecular mass of about 50 kDa that acts on the basolateral, but not apical, surface of model intestinal epithelia to elicit IL-8 secretion. PIF was not present in the media of model epithelia stimulated with other inducers of IL-8 secretion (TNF-alpha or carbachol) but was present in S. typhimurium supernatants, indicating PIF is of bacterial origin. PIF was purified from bacterial culture supernatants by anion/cation exchange chromatography and SDS-PAGE and found by using microsequencing to be the protein flagellin. In support of this finding, flagellin-deficient S. typhimurium mutants did not secrete detectable levels of PIF (i.e., a bioactivity that induced IL-8 secretion when placed basolaterally on model epithelia). Furthermore, viable flagellin-deficient mutant organisms (fliC/fljB and flhD) failed to elicit IL-8 secretion when added apically to model intestinal epithelia. These findings indicate that translocation of flagellin across epithelia, subsequent to apical epithelial-S. typhimurium interaction, is likely a major means of activating a mucosal inflammatory response. Salmonella typhimurium translocates flagellin across intestinal epithelia, inducing a proinflammatory response Andrew Gewirtz Peter Simon Clare Schmitt Laura Taylor Curt Hagedorn Alison O'Brien Andrew Neish James Madara J. Clin. Invest., Vol. 107, No. 1. (1 January 2001), pp. 99-109. 2007-09-10T15:29:36-00:00 2001 J. Clin. Invest. 107 1 99 109 flagellin-biphasic