CysLT2 receptor mediates lipopolysaccharide-induced microglial inflammation and consequent neurotoxicity in vitro

Neuroinflammation induced by microglial activation plays a critical role in many neurodegenerative diseases, including Parkinson's disease (PD). Recent studies have indicated that cysteinyl leukotriene receptor 2 (CysLT2R) is involved in inflammation and brain injury after cerebral ischemia. However, the role of CysLT2R in microglial responses associated with PD remains unclear. In the present study, we determined the regulatory roles of CysLT2R in microglial inflammation and subsequent neurotoxicity in an in vitro brain inflammation model induced by the microglial activator lipopolysaccharide (LPS). We found that LPS induced phagocytosis of a murine microglial cell line (BV-2 cells) and increased production of the proinflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β). The expression of CysLT2R protein was up-regulated and the nuclear translocation of CysLT2R was induced in LPS-activated BV-2 cells. CysLT2R selective antagonist HAMI 3379 significantly inhibited LPS-induced phagocytosis and overproduction of the cytokines in BV-2 cells. Similarly, the CysLT2R silencing by specific short hairpin RNA (shRNA) had the same effects as those of HAMI 3379, suggesting that the effect might be CysLT2R-dependent. Furthermore, the conditioned medium (CM) derived from LPS-treated BV-2 cells induced the cell death of a rat adrenal pheochromocytoma cell line (PC12). HAMI 3379 and CysLT2R shRNA attenuated neuronal death by suppressing the production of neurotoxic cytokines released from LPS-activated microglia. Collectively, these results suggest that CysLT2R mediates LPS-induced microglial inflammation and consequent neurotoxicity. CysLT2R may be a promising molecular target that modulates microglia-related neuroinflammation in neurodegenerative disorders, such as PD.