ABSTRACT
OBJECTIVE Alzheimer's disease(AD)is the most common neurodegenerative disease worldwide.Neuroinflammation is a potential target for the patients with AD.It is attributed to activated microglia and the release of various inflammatory mediators from infec-tion,ischemia and toxin accumulation.Accumulating evi-dence has indicated that the cGAS-STING pathway driven neuroinflammation in neurological disease.TSG is a main natural active ingredient that derived from polyg-onum multiflorum.Previous research from our group found that TSG has beneficial effects of anti-aging,anti-inflammatory action and improving memory function in APP/PS1 transgenic AD mice.Here,we investigated the effects of TSG on cognitive impairment and neuroinflam-mation in APP/PS1-AD mice and explore the underly-ing mechanism by which TSG ameliorates memory func-tion in the cGAS-STING-mediated inflammatory response.METHODS The Morris water mace test and the novel object recognition test were performed to test the effects of TSG on spatial learning and cognitive and memory abil-ity in APP/PS1 double transgenic AD mice model.In addi-tion,real-time quantitative PCR,Western blotting,ELISA analysis,and flow cytometry to examine gene and pro-tein expression of cGAS-STING related pro-inflammatory cytokines and chemokines.Statistical analyses were ana-lyzed using the SPSS 25.0 package by analysis of vari-ance(ANOVA).Neuman-Keuls or Tukey's multiple-com-parisons test were conducted as ANOVA justified post hoc comparisons between group means.RESULTS We demonstrated that AD transgenic mice exhibited cognitive deficits accompanied by the elevated serum and brain inflammation.The expressions of serum inflammatory cytokines and the activation of microglia in cerebral cor-tex and hippocampus were suppressed after TSG treat-ment,which was probably attributable to the decrease of cyclic GMP-AMP synthase(cGAS)and stimulator of interferon genes(STING)triggered immune response.Additionally,the data showed that TSG treatment reduced the expression level of inflammatory cytokines(IL-1β,TNF-α,IFN-β,IFN-α)in microglial cells BV2 primed with LPS and IFN-γ.CONCLUSION TSG implicated the health benefits in preventing cognitive disorders by inhib-iting neuroinflammation via cGAS-STING signalling path-way in AD.
ABSTRACT
Objective: To investigate the neuroprotective effect and mechanism of tetrahydroxy stilbene glucoside (TSG) on β-amyloid protein 25-35 (Aβ25-35)-induced neuron synapses damage. Method: Primary neurons were isolated and purified from cerebral cortex of suckling mouse. Then neurons were divided into control group, model group (incubation with Aβ25-35) and TSG groups (after incubation with Aβ25-35, add 6.25, 12.5, 25, 50, 100 μmol·L-1 TSG). Cell counting kit-8 (CCK-8) and Lactate dehydrogenase (LDH) methods were used to observe the viability of neuron, immunocytochemical staining was performed to determine the expressions of synapsin-1 (SYN-1), and the concentration of postsynaptic density-95 (PSD-95) and synaptophysin (SYP) were detected by enzyme-linked immunosorbent assay (ELISA) method. The level of cyclic adenosine monophosphate response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) mRNA were determined by reverse transcription-polymerase chain reaction (RT-PCR) and the level of CREB, Phosphorylated CREB (p-CREB) and BDNF proteins were determined by immunocytochemical staining or Western blot (WB). Result: Compared with normal group, the cell survival rate of model group was significantly reduced, LDH release was significantly increased (PPPPPPP-1,25 μmol·L-1 TSG can significantly enhance the expression of SYN-1(PPPPConclusion: TSG possesses the neuroprotective effect on Aβ25-35-induced neuron synapses, the mechanism may be associated with the activation of CREB/BDNF signaling pathway.
ABSTRACT
@#Objective To investigate the deficit of extracellular-signal regulated kinase (ERK)1/2 activation in the different age of Alzheimer's disease (AD)-like animal model and the protective effect of 2,3,5,4′-tetrahydroxy stilbene-2-O-β-D-glucoside(TSG), which is the main component of Polygonum multiflorum, on ERK activation. Methods A generally accepted animal model of AD - PDAPPV717I transgenic (Tg) mouse was observed from 4 to 16 months old. Tg mice were randomly divided into 3 model groups(4, 10 and 16 months old mice)and TSG treated (at doses 120 and 240 μmol/kg/d) groups. TSG was administered to some Tg mice with an age range 4-10 months. In untreated 10 months old Tg mice, the TSG was administrated to those falling in the age range 10-16 months. For the control group we adopted the same age and background C57BL/6J mice. The ERK1/2 expression and phosphorylation were detected by Western blotting.Results In the 4-month-old PDAPPV717I Tg mice, phosphorylation of ERK1/2 decreased significantly in hippocampus and cortex compared with age matched control. In the 10-month-old Tg mice, decrease of ERK1/2 activation was aggravated in cortex but was less in hippocampus. The treatment of TSG at the doses of 120 and 240 μmol/kg for 6 months (from the age of 4 to 10 months) significantly up-regulated ERK1/2 activation in Tg mice. In the 16-month-old Tg mice, over-activation of ERK1/2 occurred in both hippocampus and cortex. The transgenic mice treated by TSG for 6 months (from the age of 10 months to 16 months) showed significant inhibition of over-activation of ERK1/2. Expression of total ERK1/2 showed no difference among control, Tg model and TSG treated groups.Conclusion PDAPPV717I transgenic mice with an age range from 4 to 16 months revealed the time-dependent deficit of ERK1/2 activation. TSG can bring the down or over activation of ERK1/2 into normal. Because ERK1/2 activation plays the crucial role in cellular signal transduction and learning-memory ability, TSG may have beneficial potential to the prevention and treatment of neurodegenerative diseases like AD.