[Show abstract][Hide abstract] ABSTRACT: Microglia play key roles in innate immunity, homeostasis, and neurotropic support in the central nervous system. Similar to macrophages, microglia adopt two different activation phenotypes, the classical and alternative activation. Resolvin D1 (RvD1) is considered to display potent anti-inflammatory and pro-resolving actions in inflammatory models. In this present study, we investigate the effect of RvD1 on IL-4-induced alternative activation in murine BV-2 microglial cells.
BV-2 cells were incubated with RvD1 alone, IL-4 alone, or the combination of RvD1 and IL-4. Western blot and immunofluorescence were performed to detect protein levels of alternative activation markers arginase 1 (Arg1), chitinase 3-like 3 (Ym1). Moreover, we investigated the effects of RvD1 on IL-4-induced activation of signal transducer and activators of transcription 6 (STAT6) and peroxisome proliferator-activated receptor gamma (PPARgamma).
RvD1 promoted IL-4-induced microglia alternative activation by increasing the expression of Arg1 and Ym1. RvD1 also enhanced phosphorylation of STAT6, nuclear translocation of PPARgamma and the DNA binding activity of STAT6 and PPARgamma. These effects were reversed by butyloxycarbonyl-Phe-Leu-Phe-Leu-Phe (a formyl peptide receptor 2 antagonist). Further, the effects of RvD1 and IL-4 on Arg1 and Ym1 were blocked by the application of leflunomide (a STAT6 inhibitor) or GW9662 (a PPARgamma antagonist).
Our studies demonstrate that RvD1 promotes IL-4-induced alternative activation via STAT6 and PPARgamma signaling pathways in microglia. These findings suggest that RvD1 may have therapeutic potential for neuroinflammatory diseases.
Journal of Neuroinflammation 04/2014; 11(1):72. · 4.35 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Lipoxins have emerged as mediators of key events in endogenous anti-inflammation and resolution. However, the implication of these novel lipid mediators on neuroinflammation has not been investigated. Microglia is the major cells involved in brain tissue damage during infection and neurodegenerative diseases. One of the major features shared by neuroinflammation conditions is the increased production of reactive oxygen species (ROS) generated by NADPH oxidase activation. In this study, we have examined whether aspirin-triggered lipoxin A(4) (ATL) modulates ROS generation in BV2 cells. Pre-treatment of BV2 cells with ATL blocked ROS production triggered by LPS in the time-dependent and concentration-dependent manner. ATL inhibited the translocation of the cytoplasmic NADPH oxidase subunit p47(phox) to the cell membrane as well as NADPH oxidase activity. Taken together, these results demonstrate that ATL suppresses NADPH oxidase-mediated ROS generation in BV2 microglia cells, strongly indicating that ATL may play an important role against the development and progression of neuroinflammtion.
Neurochemical Research 05/2012; 37(8):1690-6. · 2.13 Impact Factor