Cysteinyl leukotriene receptor 1 mediates LTD4-induced activation of mouse microglial cells in vitro

Aim: To investigate the roles of cysteinyl leukotriene receptors CysLT(1)R and CysLT(2)R in leukotriene D-4 (LTD4)-induced activation of microglial cells in vitro. Methods: Mouse microglial cell line BV2 was transfected with pcDNA3.1(+)-hCysLT(1)R or pcDNA3.1(+)-hCysLT(2)R. The expression of relevant mRNAs and proteins in the cells was detected using RT-PCR and Western blotting, respectively. Phagocytosis was determined with flow cytometry analysis. The release of interleukin-1 beta(IL-1 beta) from the cells was measured using an ELISA assay. Results: The expression of CysLT(1)R or CysLT(2)R was considerably increased in the transfected BV2 cells, and the receptors were mainly distributed in the plasma membrane and cytosol. Treatment of the cells expressing CysLT(1)R or CysLT(2)R with CysLT receptor agonist LTD4 (0.1-100 nmol/L) concentration-dependently enhanced the phagocytosis, and increased mRNA expression and release of IL-1 beta. Moreover, the responses of hCysLT(1)R-BV2 cells to LTD4 were significantly larger than those of hCysLT(2)R-BV2 or WT-BV2 cells. Pretreatment of hCysLT(1)R-BV2 cells with the selective CysLT(1)R antagonist montelukast (1 mu mol/L) significantly blocked LTD4-induced phagocytosis as well as the mRNA expression and release of IL-1 beta, whereas the selective CysLT(2)R antagonist HAMI 3379 (1 mu mol/L) had no such effects. Conclusion: CysLT(1)R mediates LTD4-induced activation of BV2 cells, suggesting that CysLT1R antagonists may exert anti-inflammatory activity in brain diseases.