EriB targeted inhibition of microglia activity attenuates MPP + induced DA neuron injury through the NF-κB signaling pathway.

Accumulating evidence indicates that microglia activation is associated with an increased risk for developing Parkinson's disease (PD). With the progressive and selective degeneration of dopaminergic (DA) neurons, proinflammatory cytokines are elevated in the substantia nigra (SN) of PD patients. Thus, anti-inflammation has become one of the therapeutic strategies of PD. Eriocalyxin B (EriB), a diterpenoid isolated from Isodoneriocalyx, was previously reported to have anti-inflammatory effects. MPTP mouse model and MPP+ cell model were prepared to detect the role of EriB in regulating microglia activation and neuron protection. Midbrain tissue and primary cultured microglia and neuron were used to examine microglia activation and neuron damage by immunofluorescence, real-time PCR, western-blot and Elisa assay. Open field activity test was to evaluate the changes of behavioral activity in MPTP-induced PD mouse model. EriB was efficacious in protecting DA neurons by inhibiting microglia activation in PD mice model. Treatment with EriB led to amelioration of disordered sports of PD mice model, which correlated with reduced microglia-associated inflammation and damaged DA neurons. EriB treatment abolished MPP+ induced microglia activation damages to DA neurons in a microglia and DA neurons co-culture system. The underlying mechanism of EriB-induced protective effects involved inhibition of microglia associated proinflammatory cytokines production through the phenotypic shift of microglial cells as well as activator of transcription and nuclear factor-κB (NF-κB) signaling pathways. These findings demonstrate that EriB exerts potent anti-inflammatory effects through selective modulation of microglia activation by targeting NF-κB signaling pathways, thus exerting the protective effect against on MPP+ -induced DA neurons injury. This study may provide insights into the promising therapeutic role of EriB for PD.