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Differential gene expression mediated by 15-hydroxyeicosatetraenoic acid in LPS-stimulated RAW 264.7 cells.

Schrimpe AC, Wright DW - Malar. J. (2009)

Bottom Line: 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.These results add insight and detail to 15-HETE's effects on gene expression in macrophage-like cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, USA. a.schrimpe@vanderbilt.edu

ABSTRACT

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

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.

Conclusion: 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.

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Related in: MedlinePlus

Comparison of differentially expressed genes mediated by 15-HETE, beta-haematin, and latex beads. Venn diagrams show the intersection of genes that were transcriptionally altered by 40 μM 15-HETE with those altered by latex bead treatment and serum-opsonized beta haematin (BH) (0.1 mg/mL). Numbers represent statistically significant (p ≤ 0.025) transcripts up- or down-regulated ≥ 1.8-fold in 2 of 3 samples, relative to LPS-stimulated untreated cells at 24 h. (A) Decreased and (B) increased expression are shown separately.
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Figure 1: Comparison of differentially expressed genes mediated by 15-HETE, beta-haematin, and latex beads. Venn diagrams show the intersection of genes that were transcriptionally altered by 40 μM 15-HETE with those altered by latex bead treatment and serum-opsonized beta haematin (BH) (0.1 mg/mL). Numbers represent statistically significant (p ≤ 0.025) transcripts up- or down-regulated ≥ 1.8-fold in 2 of 3 samples, relative to LPS-stimulated untreated cells at 24 h. (A) Decreased and (B) increased expression are shown separately.

Mentions: LPS-stimulated macrophage-like RAW 264.7 cells were treated for 24 h with 40 μM 15(S)-HETE based on the estimate that trophozoites and Hz contained 33–39 μmol 15-HETE/L RBC [5]. Statistically significant (p ≤ 0.025) changes in gene expression (fold change ≥ 1.8 relative to stimulated cells) were identified by microarray analysis. Given that this study aims to explore potential alterations in gene expression that are incurred by 15-HETE during haemozoin phagocytosis, differentially expressed mRNAs were controlled by comparison with a particulate latex bead challenge and BH treatment under the same conditions. Figure 1 illustrates that 15-HETE had a much greater effect on induction of gene expression than repression (293 transcripts versus 100 transcripts, respectively), but overall was very modest compared to either latex bead or BH treatment.


Differential gene expression mediated by 15-hydroxyeicosatetraenoic acid in LPS-stimulated RAW 264.7 cells.

Schrimpe AC, Wright DW - Malar. J. (2009)

Comparison of differentially expressed genes mediated by 15-HETE, beta-haematin, and latex beads. Venn diagrams show the intersection of genes that were transcriptionally altered by 40 μM 15-HETE with those altered by latex bead treatment and serum-opsonized beta haematin (BH) (0.1 mg/mL). Numbers represent statistically significant (p ≤ 0.025) transcripts up- or down-regulated ≥ 1.8-fold in 2 of 3 samples, relative to LPS-stimulated untreated cells at 24 h. (A) Decreased and (B) increased expression are shown separately.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2743705&req=5

Figure 1: Comparison of differentially expressed genes mediated by 15-HETE, beta-haematin, and latex beads. Venn diagrams show the intersection of genes that were transcriptionally altered by 40 μM 15-HETE with those altered by latex bead treatment and serum-opsonized beta haematin (BH) (0.1 mg/mL). Numbers represent statistically significant (p ≤ 0.025) transcripts up- or down-regulated ≥ 1.8-fold in 2 of 3 samples, relative to LPS-stimulated untreated cells at 24 h. (A) Decreased and (B) increased expression are shown separately.
Mentions: LPS-stimulated macrophage-like RAW 264.7 cells were treated for 24 h with 40 μM 15(S)-HETE based on the estimate that trophozoites and Hz contained 33–39 μmol 15-HETE/L RBC [5]. Statistically significant (p ≤ 0.025) changes in gene expression (fold change ≥ 1.8 relative to stimulated cells) were identified by microarray analysis. Given that this study aims to explore potential alterations in gene expression that are incurred by 15-HETE during haemozoin phagocytosis, differentially expressed mRNAs were controlled by comparison with a particulate latex bead challenge and BH treatment under the same conditions. Figure 1 illustrates that 15-HETE had a much greater effect on induction of gene expression than repression (293 transcripts versus 100 transcripts, respectively), but overall was very modest compared to either latex bead or BH treatment.

Bottom Line: 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.These results add insight and detail to 15-HETE's effects on gene expression in macrophage-like cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, USA. a.schrimpe@vanderbilt.edu

ABSTRACT

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

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.

Conclusion: 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.

Show MeSH
Related in: MedlinePlus