Differential gene expression mediated by 15-hydroxyeicosatetraenoic acid in LPS-stimulated RAW 264.7 cells.
BACKGROUND
Given the immuno-modulatory activity of native haemozoin (Hz), the effects of constitutive Hz components on immune response are of interest. Recently, gene expression changes mediated by HNE and the synthetic analogue of Hz, beta-haematin (BH), were identified and implicated a significant role for lipid peroxidation products in Hz's activity. The study presented herein examines gene expression changes in response to 15(S)-hydroxyeicosatetraenoic acid (HETE) in a model macrophage cell line.


METHODS
LPS-stimulated RAW 264.7 macrophage-like cells were treated with 40 microM 15(S)-HETE for 24 h, and microarray analysis was used to identify global gene expression alterations. Fold changes were calculated relative to LPS-stimulated cells and those genes altered at least 1.8-fold (p value <or= 0.025) were considered to be differentially expressed. Expression levels of a subset of genes were assessed by qRT-PCR and used to confirm the microarray results.


RESULTS
Network analysis revealed that altered genes were primarily associated with "lipid metabolism" and "small molecule biochemistry". While several genes associated with PPAR-gamma receptor-mediated signaling were differentially expressed, a number of genes indicated the activation of secondary signaling cascades. Genes related to cytoadherence (cell-cell and cell-matrix), leukocyte extravasation, and inflammatory response were also differentially regulated by treatment, supporting a potential role for 15(S)-HETE in malaria pathogenesis.


CONCLUSIONS
These results add insight and detail to 15-HETE's effects on gene expression in macrophage-like cells. Data indicate that while 15-HETE exerts biological activity and may participate in Hz-mediated immuno-modulation, the gene expression changes are modest relative to those altered by the lipid peroxidation product HNE.
Schrimpe
Alexandra C
AC
Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, USA. a.schrimpe@vanderbilt.edu
Wright
David W
DW
D000818:Animals; D002460:Cell Line; D015870:Gene Expression / Q000187:drug effects*; D020869:Gene Expression Profiling; D006893:Hydroxyeicosatetraenoic Acids / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology*; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology*; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
D006893:Hydroxyeicosatetraenoic Acids; D008070:Lipopolysaccharides