Identification of Pseudomonas aeruginosa-induced genes in human mast cells using suppression subtractive hybridization: up-regulation of IL-8 and CCL4 production.

Mast cells have recently been found to be a major player in the host defence against bacterial infection through secretion of potent mediators. Identification of bacteria-induced mast cell mediators and intracellular signalling molecules involved during bacterial infection remains a major area of investigation. Recently we found an active interaction between mast cells and Pseudomonas aeruginosa bacteria. To further characterize specific genes in mast cells modulated by P. aeruginosa, we used a new approach for the study of mast cell-bacteria interaction; the suppression subtractive hybridization (SSH). SSH approach does not require a prerequisite knowledge of target genes and does not rely on the availability of the assay reagents for the specific genes. Using SSH, 94 clones were randomly selected from the subtracted cDNA library for differential screening leading to the identification of 14 P. aeruginosa-up-regulated transcripts. Sequence analysis revealed that expression of IL-1, IL-8 and CCL4 was increased by human mast cells after P. aeruginosa infection. Increased production of IL-1, IL-8 and CCL4 was confirmed at the protein levels. In addition, sequence analysis of the clones also suggests that ribosomal protein S3 and cytochrome b as well as additional 4 uncharacterized genes may potentially be involved in P. aeruginosa pathogenesis. Thus, SSH is an effective approach by identifying potential molecular targets for the study of mechanisms involved in P. aeruginosa and mast cell interaction.