Gene expression modulation in chicken macrophages exposed to Mycoplasma synoviae or Escherichia coli

Mycoplasma synoviae and Escherichia coli are two avian pathogens that exhibit markedly different mechanisms for infection and pathogenicity and may be expected to manipulate the host innate immune response differently. The aim of this study was to determine the extent of modulated genes and make a comparison between the transcriptomes of chicken macrophages exposed to either M. synoviae type strain WVU 1853 (MS) or avian pathogenic E. coli strain V-G (APEC). To analyze temporal gene expression profile of monocyte-derived macrophages (MDM) and HD11 cell line macrophages after each exposure, two avian immunity microarrays were used: the avian macrophage microarray (AMM) and the avian innate immunity microarray (AIIM). The quantity of MS-modulated genes was estimated in three experiments, using both microarrays. A cross-section revealed 14 AMM/AIIM genetic elements that were modulated in both types of macrophages. Additionally, to compare immunomodulatory activity of MS and APEC, MDM were exposed to each pathogen and gene modulation was detected by AIIM microarray. This study revealed 157 elements uniquely modulated by MS and 1603 elements uniquely modulated by APEC. AIIM microarray analysis also revealed a core set of 146 elements modulated by both pathogens, with generally higher induction/repression levels after APEC exposure. Validation of selected gene expression was done by quantitative real time RT-PCR. The study shows higher transcription levels of IL-1β, IL-6, iNOS, NCF1, peroxiredoxin 1 and cathepsin L genes after MDM exposure to APEC than after exposure to MS. Surprisingly, complement component C3 gene was repressed after MDM exposure to APEC, while being induced after exposure to MS.