RRBP1 Inhibition Reduces Microglial M1 Polarization and Inflammation-Mediated Neuronal Loss and Oxidative Stress by Regulating ERK Pathway in Alzheimer’s Disease
摘要
Ribosome-binding protein 1 (RRBP1) regulates ribosome assembly and stability to modify several important biological processes such as mitochondrial function, stress, cell differentiation, immunity, and axonal structure. This study aimed to investigate RRBP1 inhibition on microglial polarization and inflammation, and its mediated neuronal loss and oxidative stress in Alzheimer’s disease (AD). Mouse microglia (BV-2), mouse hippocampal neuron (HT-22), human microglia (HMC3), and human neuroblastoma (SH-SY5Y) cell lines were cultured. A classical culture system containing BV-2 and HT-22, as well as HMC3 and SH-SY5Y, under β-amyloid treatment was applied to mimic AD cellular models. RRBP1 siRNA and control siRNA were transfected into BV-2 and HMC3 cells with no transfection as normal control; moreover, the ERK pathway was inactivated by PD98059 reagent. Microglial M1 phonotype marker (iNOS) and inflammatory cytokines (TNF-α and IL-1β levels) were decreased, while microglial M2 phonotype marker (ARG1) and pERK/ERK were increased by RRBP1 inhibition in BV-2 and HMC3 cells. Then microglial RRBP1 inhibition further elevated cell viability and superoxide dismutase (SOD), while reducing the cell apoptosis rate and reactive oxygen species (ROS) in HT-22 and SH-SY5Y cells. pERK/ERK was lowered after PD98059 treatment, which attenuated the effect of RRBP1 inhibition on microglial M1/M2 phenotypes and inflammatory cytokines in BV-2 and HMC3 cells, and further weakened the effect of microglial RRBP1 inhibition on cell viability, apoptosis rate, ROS, and SOD in HT-22 and SH-SY5Y cells. RRBP1 inhibition represses microglial M1 polarization and inflammation-mediated neuronal loss and oxidative stress by modifying the ERK pathway in AD.