High mobility group box 1
protein (
HMGB1) is potentially triggered by Aβ oligomers and other sterile
injuries, and is a non-
histone DNA binding
nuclear protein with roles in neural development and neurodegeneration, which contribute to memory impairment and chronic
neuroinflammation in the brain. However, the exact molecular mechanisms of
HMGB1 activation in
Alzheimer's disease (AD) were previously unknown. The present study aimed to elucidate the effects of
HMGB1 in Aβ25-35-induced
neuroinflammation in hippocampal neuron cultures. RNA interference (RNAi)
HMGB1 treatment significantly reduced Aβ25-35-induced
HMGB1 expression by almost 70% in primary hippocampal neurons. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and
enzyme-linked
immunosorbent assay (ELISA) demonstrated that
short hairpin RNA (
shRNA) for
HMGB1 ameliorated Aβ25-35-treated
neuroinflammation, including activation of advanced glycosylation end product-specific receptor (RAGE),
toll-like receptor 4 (TLR4), and
nuclear factor-kappa B (NF-κB)-p65, as well as induced the release of inflammatory mediators such as
tumor necrosis factor-α (TNF-α),
interleukin 1β (IL-1β),
IL-6, and
HMGB1 in primary hippocampal neurons and the culture supernatant. In addition, pretreatment with HMGB1-shRNA dramatically reduced both the degree of nuclear-cytoplasmic
HMGB1 translocation of
HMGB1 and NF-κB
DNA binding. Together, the data indicate that
HMGB1 mediates the pathogenesis of AD by activating RAGE/TLR4 signaling and that
shRNA targeting
HMGB1 may be a promising therapeutic strategy for treating AD.