Regulation of human beta-defensins by gastric epithelial cells in response to infection with Helicobacter pylori or stimulation with interleukin-1.

Gastric epithelial cells in vitro and in vivo are shown to constitutively express the peptide antibiotic human beta-defensin type 1 (hBD-1). In contrast, hBD-2 expression is regulated in gastric epithelial cells and increases in response to infection with Helicobacter pylori or stimulation with the proinflammatory cytokine interleukin-1. These data suggest that hBD-2 is a component of the regulated host gastric epithelial cell response to H. pylori infection and proinflammatory mediators.

Analysis by high density cDNA arrays of altered gene expression in human intestinal epithelial cells in response to infection with the invasive enteric bacteria Salmonella.

Many clinically important enteric pathogens initiate disease by invading and passing through the intestinal epithelium, a process accompanied by increased epithelial expression of proinflammatory cytokines. To further define the role intestinal epithelial cells play in initiating and modulating the host response to infection with invasive bacteria, hybrid selection on high density cDNA arrays was used to characterize the mRNA expression profile of approximately 4,300 genes in human intestinal epithelial cells after infection with the prototypic invasive bacteria, Salmonella. Selected findings were further evaluated by reverse transcription-polymerase chain reaction, Northern blot analysis, and protein assays. Epithelial infection with Salmonella significantly up-regulated mRNA expression of a relatively small fraction of all genes tested. Of these, several cytokines (granulocyte colony-stimulating factor, inhibin A, Epstein-Barr virus-induced gene 3, interleukin-8, macrophage inflammatory protein-2alpha), kinases (TKT, Eck, HEK), transcription factors (interferon regulatory factor-1), and HLA class I were the most prominent. Furthermore, the transcription factor NF-kappaB is shown to be important for inducible mRNA expression for a broad group of genes tested. These findings expand the repertoire of known epithelial cell responses to infection with an invasive enteric pathogen. The results also show that evaluation of mRNA expression profiles by cDNA array analysis is a powerful approach to characterizing and understanding host-pathogen interactions.