Critical role of TLR2 and MyD88 for functional response of macrophages to a group IIA-secreted phospholipase A2 from snake venom.

Abstract

The snake venom MT-III is a group IIA secreted phospholipase A2 (sPLA2) enzyme with functional and structural similarities with mammalian pro-inflammatory sPLA2s of the same group. Previously, we demonstrated that MT-III directly activates the innate inflammatory response of macrophages, including release of inflammatory mediators and formation of lipid droplets (LDs). However, the mechanisms coordinating these processes remain unclear. In the present study, by using TLR2-/- or MyD88-/- or C57BL/6 (WT) male mice, we report that TLR2 and MyD88 signaling have a critical role in MT-III-induced inflammatory response in macrophages. MT-III caused a marked release of PGE2, PGD2, PGJ2, IL-1β and IL-10 and increased the number of LDs in WT macrophages. In MT-III-stimulated TLR2-/- macrophages, formation of LDs and release of eicosanoids and cytokines were abrogated. In MyD88-/- macrophages, MT-III-induced release of PGE2, IL-1β and IL-10 was abrogated, but release of PGD2 and PGJ2 was maintained. In addition, COX-2 protein expression seen in MT-III-stimulated WT macrophages was abolished in both TLR2-/- and MyD88-/- cells, while perilipin 2 expression was abolished only in MyD88-/- cells. We further demonstrated a reduction of saturated, monounsaturated and polyunsaturated fatty acids and a release of the TLR2 agonists palmitic and oleic acid from MT-III-stimulated WT macrophages compared with WT control cells, thus suggesting these fatty acids as major messengers for MT-III-induced engagement of TLR2/MyD88 signaling. Collectively, our findings identify for the first time a TLR2 and MyD88-dependent mechanism that underlies group IIA sPLA2-induced inflammatory response in macrophages.

• Authors: Elbio Leiguez, Karina Cristina Giannotti, Vanessa Moreira, Márcio Hideki Matsubara, José María Gutiérrez, Bruno Lomonte, Juan Pablo Rodríguez, Jesús Balsinde, Catarina Teixeira
• Journal: PloS one (PLoS One) Vol. 9 Issue 4 Pg. e93741 ( 2014) ISSN: 1932-6203 [Electronic] United States
• PMID: 24718259 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Fatty Acids
• Interleukin-1beta
• Membrane Proteins
• Myeloid Differentiation Factor 88
• Perilipin-2
• Prostaglandins
• Snake Venoms
• Tlr2 protein, mouse
• Toll-Like Receptor 2
• Interleukin-10
• Ptgs2 protein, mouse
• Cyclooxygenase 2
• Group II Phospholipases A2

Topics

• Animals
• Cyclooxygenase 2 (metabolism)
• Fatty Acids (metabolism)
• Group II Phospholipases A2 (pharmacology)
• Interleukin-10 (metabolism)
• Interleukin-1beta (metabolism)
• Lipid Droplets (drug effects, metabolism)
• Macrophages (drug effects, metabolism)
• Male
• Membrane Proteins (metabolism)
• Mice, Inbred C57BL
• Myeloid Differentiation Factor 88 (deficiency, metabolism)
• Perilipin-2
• Prostaglandins (biosynthesis)
• Signal Transduction (drug effects)
• Snake Venoms (enzymology)
• Subcellular Fractions (drug effects, metabolism)
• Toll-Like Receptor 2 (deficiency, metabolism)
• Up-Regulation (drug effects)