A Microarray-Based Analysis of Differentially Expressed Genes in Intracellular Brucella abortus 544 within Mdbk Cells

Abstract

Background: Modulation of gene expression is a fundamental requirement for adaptation of intracellular Brucella abortus. Since most of the current understanding mainly focus on professional phagocytes and renal involvement is uncommon in brucellosis, our aim was to identify and analyze changes in B. abortus gene expression in response to intracellular environment within a bovine kidney cell line. Methodology: B. abortus RNA were isolated from Madin-Darby bovine kidney (MDBK) epithelial cells during replicative phase and the transcriptional profile of intracellular B. abortus was characterized using microarray analysis. Results and interpretation: The microarray analysis revealed a total of 1,623 differentially expressed genes of ≥ 2-fold-788 (25.44%, 788/3098) upregulated and 835 (26.95%,835/3098) down-regulated genes as compared with free-living Brucella. Among these identified genes, 81 and 185 were upregulated and down-regulated at ≥ 7-fold, respectively, showing a marked induction of genes involved in transcription and distinct repression of genes involved in translation, ribosomal structure and biosynthesis. Conclusion: The identified genes in this study may provide new insights into the molecular interactions between B. abortus and non-phagocytic bovine cell line, MDBK. In addition, several differentially highly expressed transcripts were hypothetical genes with unknown function and/or unclassified which require further characterization due to their potential contribution in the virulence and strategy of Brucella to survive and proliferate within the host.