Bambusae Caulis in Taeniam modulates neuroprotective and anti-neuroinflammatory effects in hippocampal and microglial cells via HO-1- and Nrf-2-mediated pathways

Abstract

Recent evidence indicates that microglial activation and hippocampal damage may play important roles in neurodegenerative diseases, including Alzheimer's disease. Bambusae Caulis in Taeniam has been used as a folk remedy for the treatment of hypertension and cardiovascular disease in China and Korea. In this study, the mechanism responsible for the neuroprotective and anti-neuroinflammatory effects of Bambusae Caulis in Taeniam ethyl acetate fraction (BCE) was investigated. Heme oxygenase-1 (HO-1) is an inducible enzyme expressed in response to various inflammatory stimuli. Due to its role in the anti-inflammatory signaling pathway, the expression and modulation of HO-1 are important. In this study, the neuroprotective and antineuroinflammatory effects of BCE were examined using the murine microglial BV2 and hippocampal HT22 cells. We demonstrated that the administration of BCE provided neuroprotective effects against glutamate-induced cytotoxicity in HT22 cells through the HO-1 and nuclear erythroid-2 related factor 2 (Nrf-2) signaling pathways. We also reported that BCE inhibited lipopolysaccharide (LPS)-induced pro-inflammatory cytokines and that the presence of selective inhibitors of HO-1 (SnPP) resulted in the inhibition of BCE-mediated anti-inflammatory activity in BV2 microglial cells. BCE was shown to induce HO-1 expression as well as the nuclear translocation of Nrf-2 in both microglial and hippocampal cells. These findings revealed the potential therapeutic mechanisms of BCE in neurodegenerative diseases, suggesting that HO-1 and Nrf-2 signaling may play important roles in the mediation of its neuroprotective and anti-neuroinflammatory effects.