Eicosanoid Metabolites Associated with Type-1 Interferon Production from Plasmacytoid Dendritic Cells Stimulated with Toll-like Receptors (P19-012-19). (13th June 2019) - Rowbotham, Rachelle
Abstract: Objectives: Common among several autoimmune diseases is a prominent interferon (IFN) signature caused by aberrant IFN-α production from plasmacytoid dendritic cells (pDC). This uncontrolled response occurs when pDCs are activated through endosomal toll-like receptors (TLR). Within the endosomal compartment, TLR 7/8 and 9 are stimulated through nuclear immune complexes. The objective of this work was to determine the eicosanoids associated with IFN-α production upon TLR stimulation of murine bone marrow derived dendritic cells. Methods: Female C57BL/6Ncrl mouse bone marrow was cultured in FLT3-ligand (FMS-like tyrosine kinase 3) for 8 days to generate dendritic cell subsets. On day 8, TLR ligands were added. Supernatant was analyzed for eicosanoids by liquid chromatography- mass spectrometry and cell pellets were analyzed for phospholipid fatty acid content by gas chromatography- mass spectrometry and IFN-α by ELISA. Results: Murine pDCs stimulated with TLR 7 ligand Poly U (GU-rich ssRNA40) and TLR 3 ligand Poly I: C (polyinosinic-polycytidylic acid) produced no observable IFN-α production. Upon stimulation with TLR 9 ligand ODN1585 CpG and TLR 8 ligand R848 (resiquimod), IFN-α was significantly increased with both TLR agonists as compared to unstimulated no target samples. Targeted lipidomics analysis of eicosanoids showed that in cultures stimulated with TLR8 ligand and TLR9 ligand, pro-inflammatory eicosanoid production of prostaglandin E2 and leukotriene B4 were increased. Phospholipid analysis revealed high levels of arachidonic acid and low eicosapentaenoic acid levels within the phospholipid membranes. Conclusions: Understanding the role of fatty acids associated with IFN-α production in pDCs may provide therapeutic and mechanistic targets for autoimmune diseases with an IFN signature. Funding Sources: Funding for this project was provided by university internal funds.