Timecourse of Enterococcus faecalis infection of HUC cells

This study was undertaken to identify how gene expression of the urothelial cells respond to Enterococcus infection over the course of infection. 239 hypervariable (HV) genes were found to vary significantly over the time points, indicating a biological role in infection. Correlational clustering showed these HV genes fell into distinct families indicating a defined sequence of events following infection. Early events (0-1.5 hours post infection) were associated with upregulation of not well-known but bladder-associated genes which represented early immune response, cytoskeleton remodeling and cell cycle. Up- and downregulated genes at the middle time period (1.5-8 hours post infection) represented a variety of processes, from immune response/suppression, cell cycle/apoptosis to metabolism and cytoskeleton remodeling. Several transcription factors point to multiple pathways activation. At the late time points (8-10 hours post infection) downregulated genes represented major events of cell death, matrix degradation and immune response decline. Confocal microscopy confirms major cell death at these time points. Several events and pathways, like immune response suppression or cytoskeleton remodeling via Wnt/β-catenin and/or Rho/Rac pathway, were identified throughout the time course of HUC infection by Enterococcus. Those may be new targets for preventing and/or cure Enterococcus caused pathology. Keywords: Enterococcus, time course, microarray, infection, gene expression Immortalized human urothelial cells (HUC from ATCC) were grown into multilayer urothelium mimetic for 7 days in Ham's F-12 medium containing 10% FCS changed every 2 or 3 d. Cells were counted and infected at a multiplicity of infection of 100. RNA was isolated from cells that had been infected for 30, 60, 90 min, 4, 6, 8 and 10 h and expression was measured on a microarray spotted with 22,464 long oligos (~70mers) from the UniGene database. Data was normalized as described in Dozmorov I et al., Nucleic Acids Res. 2004 Oct 28;32(19). Hypervariable genes (239) were clustered and analyzed for presence of common transcription factors, networks and signaling pathways.