Regulation of rotenone-induced microglial activation by 5-lipoxygenase and cysteinyl leukotriene receptor 1

Abstract

The 5-lipoxygenase (5-LOX) products cysteinyl leukotrienes (CysLTs) are potent pro-inflammatory mediators. CysLTs mediate their biological actions through activating CysLT receptors (CysLT1R and CysLT2R). We have recently reported that 5-LOX and CysLT1R mediated PC12 cell injury induced by high concentrations of rotenone (0.3–10μM), which was reduced by the selective 5-LOX inhibitor zileuton and CysLT1R antagonist montelukast. The purpose of this study was to examine the regulatory roles of the 5-LOX/CysLT1R pathway in microglial activation induced by low concentration rotenone. After mouse microglial BV2 cells were stimulated with rotenone (0.3–3nM), phagocytosis and release of pro-inflammatory cytokine were assayed as indicators of microglial activation. We found that rotenone (1 and 3nM) increased BV2 microglial phagocytosis and the release of the pro-inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). Zileuton and montelukast prevented rotenone (3nM)-induced phagocytosis and cytokine release. Furthermore, rotenone significantly up-regulated 5-LOX expression, induced 5-LOX translocation to the nuclear envelope, and increased the production of CysLTs. These responses were inhibited by zileuton. Rotenone also increased CysLT1R expression and induced nuclear translocation of CysLT1R. In primary rat microglia, rotenone (10nM) increased release of IL-1β and TNF-α, whereas zileuton (0.1μΜ) and montelukast (0.01μΜ) significantly inhibited this response. These results indicated that 5-LOX and CysLT1R might be key regulators of microglial activation induced by low concentration of rotenone. Interference of 5-LOX/CysLT1R pathway may be an effective therapeutic strategy for microglial inflammation.