The use of microarrays for studying the pathogenesis of Helicobacter pylori.

At present, the genomes of various microorganisms have been completely sequenced, and many others are in progress. The availability of this level of information and the computational analysis of the described sequences have led to the development of new genomic areas such as: analysis in silico, comparative genomics, functional genomics, transcriptomics, proteomics, and pharmacogenomics. Microarray technology is a powerful tool for analyzing the expression profile of thousands of genes in a global way and can be applied to the study of various biological systems. Using the complete sequences for both the H. pylori and human genome that are available in the data bases, a number of researchers have revealed important information. Some of these data offer a glimpse into the great genetic diversity of H. pylori, the differential genetic expression between the strains that shows the complexity of the response of microorganisms to different conditions of development, and into the association of gene cluster expression with clinical outcome. Other groups have examined the global transcriptional response of gastric epithelial cells to H. pylori. The majority of these studies report an alteration in gene expression related to transcription functions, transduction signals, cell cycle regulation and differentiation, development factors, proliferation/apoptosis balance, expression of membrane proteins, and inflammatory response.