(517.7) Effects of Omega-6 Fatty Acids on Interleukin-6, Phospholipase A2, and Prostaglandin-Endoperoxide Synthase 2 Gene Expression in Lipopolysaccharide-Challenged Murine Macrophages and Adipocytes

Poster Board Number: A423

Cory Swartzmiller (Denison University), Ryan Hallinan (Denison University), Cristina Caldari-Torres (Denison University)

Obese adipose tissue (AT) has been described as an organ involved in meta-inflammation-a chronic low-grade inflammation linked to the predisposition to chronic diseases. Both adipocytes and macrophages are found in AT, with obese AT containing a higher percentage of macrophages compared to lean AT. Adipocytes and macrophages can produce pro-inflammatory molecules (adipokines), with research showing that the macrophage is the primary contributor to inflammatory adipokine release by obese AT. Our lab has described differential effects of omega-6 (n-6) fatty acids (FAs) on the production of adipokines by 3T3-L1 murine adipocytes and RAW 264.7 murine macrophages. The objective of this study was to compare the effects of n-6 FAs on gene expression of inflammation-related molecules in 3T3-L1 and RAW264.7. Gene expression of interleukin-6 (IL-6), prostaglandin-endoperoxide synthase-2 (PTGS2), and phospholipase A2 (PLA2) were quantified in both of these cell lines after incubation with n-6 FAs and a lipopolysaccharide (LPS) challenge. PGTS2 and PLA2 are enzymes involved in the production of inflammatory eicosanoids, while the IL-6 gene codes for the IL-6 protein. Macrophages were pre-incubated with 100 μM of linoleic acid (LA; n-6) or arachidonic acid (ARA; n-6) for 24 h, followed by a 6 h, 0.01 μg/ml LPS challenge. Fibroblasts (3T3-L1) were differentiated into adipocytes with the addition of 100 μM of one of the n-6 FAs throughout the differentiation period, followed by a 6 h, 1 μg/ml LPS challenge once they were fully differentiated. After LPS challenge, RNA was extracted for quantitative PCR analysis. Fatty acid treatments had no effect on expression of the target genes (IL-6, PTGS2, PLA2) in 3T3-L1 cells (two-way ANOVA).  PTGS2 expression was downregulated in LA (0.24 ± 0.13 2ΔΔCt ) and ARA (0.16 ± 0.13 2ΔΔCt)-treated macrophages challenged with LPS compared to control (1.07 ± 0.13 2ΔΔCt) and LPS (1.70 ± 0.13 2ΔΔCt)-challenged macrophages (two-way ANOVA; plt;0.0001). There were no significant LPS or LPS+n-6 FA effects on gene expression of IL-6 and PLA2 in macrophages (two-way ANOVA). Time-response experimentation is necessary to determine the kinetic model of gene expression of these target genes in both cell lines.

lt;ulgt;lt;li dir="ltr" aria-level="1"gt;Denison University Department of Biology amp;amp; the Lisska Center for Scholarly Engagement
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