Edaravone Dexborneol ameliorates the cognitive deficits of APP/PS1 mice by inhibiting TLR4/MAPK signaling pathway via upregulating TREM2.

Currently, there are no effective therapeutic agents available to treat Alzheimer's disease (AD). However, edaravone dexborneol (EDB), a novel composite agent used to treat acute ischemic stroke, has recently been shown to exert efficacious neuroprotective effects. However, whether EDB can ameliorate cognitive deficits in AD currently remains unclear. To this end, we explored the effects of EDB on AD and its potential mechanisms using an AD animal model (male APP/PS1 mice) treated with EDB for 10 weeks starting at 6 months of age. Subsequent analyses revealed that EDB-treated APP/PS1 mice exhibited improved cognitive abilities compared to untreated APP/PS1 mice. Administration of EDB in APP/PS1 mice further alleviated neuropathological alterations of the hippocampus, including Aβ deposition, pyramidal cell karyopyknosis, and oxidative damage, and significantly decreased the levels of inflammatory cytokines (IL-1β, IL-6 and TNF-α) and COX-2 in the hippocampus of APP/PS1 mice. Transcriptome sequencing analysis demonstrated the critical role of the inflammatory reaction in EDB treatment in APP/PS1 mice, indicating that the alleviation of the inflammatory reaction by EDB in the hippocampus of APP/PS1 mice was linked to the action of the TREM2/TLR4/MAPK signaling pathway. Further in vitro investigations showed that EDB suppressed neuroinflammation in LPS-stimulated BV2 cells by inhibiting the TLR4/MAPK signaling pathway and upregulating TREM2 expression. Thus, the findings of the present study demonstrate that EDB is a promising therapeutic agent for AD-related cognitive dysfunction.

Wang J ，Du L ，Zhang T ，Chu Y ，Wang Y ，Wang Y ，Ji X ，Kang Y ，Cui R ，Zhang G ，Liu J ，Shi G ... -  《-》

Imbalance of Microglial TLR4/TREM2 in LPS-Treated APP/PS1 Transgenic Mice: A Potential Link Between Alzheimer's Disease and Systemic Inflammation.

Zhou J ，Yu W ，Zhang M ，Tian X ，Li Y ，Lü Y ... -  《-》

Zerumbone ameliorates behavioral impairments and neuropathology in transgenic APP/PS1 mice by suppressing MAPK signaling.

Li L ，Wu XH ，Zhao XJ ，Xu L ，Pan CL ，Zhang ZY ... -  《Journal of Neuroinflammation》

Long-term running exercise improves cognitive function and promotes microglial glucose metabolism and morphological plasticity in the hippocampus of APP/PS1 mice.

The role of physical exercise in the prevention of Alzheimer's disease (AD) has been widely studied. Microglia play an important role in AD. Triggering receptor expressed in myeloid cells 2 (TREM2) is expressed on microglia and is known to mediate microglial metabolic activity and brain glucose metabolism. However, the relationship between brain glucose metabolism and microglial metabolic activity during running exercise in APP/PS1 mice remains unclear. Ten-month-old male APP/PS1 mice and wild-type mice were randomly divided into sedentary groups or running groups (AD_Sed, WT_Sed, AD_Run and WT_Run, n = 20/group). Running mice had free access to a running wheel for 3 months. Behavioral tests, [18]F-FDG-PET and hippocampal RNA-Seq were performed. The expression levels of microglial glucose transporter (GLUT5), TREM2, soluble TREM2 (sTREM2), TYRO protein tyrosine kinase binding protein (TYROBP), secreted phosphoprotein 1 (SPP1), and phosphorylated spleen tyrosine kinase (p-SYK) were estimated by western blot or ELISA. Immunohistochemistry, stereological methods and immunofluorescence were used to investigate the morphology, proliferation and activity of microglia. Long-term voluntary running significantly improved cognitive function in APP/PS1 mice. Although there were few differentially expressed genes (DEGs), gene set enrichment analysis (GSEA) showed enriched glycometabolic pathways in APP/PS1 running mice. Running exercise increased FDG uptake in the hippocampus of APP/PS1 mice, as well as the protein expression of GLUT5, TREM2, SPP1 and p-SYK. The level of sTREM2 decreased in the plasma of APP/PS1 running mice. The number of microglia, the length and endpoints of microglial processes, and the ratio of GLUT5+/IBA1+ microglia were increased in the dentate gyrus (DG) of APP/PS1 running mice. Running exercise did not alter the number of 5-bromo-2'-deoxyuridine (BrdU)+/IBA1+ microglia but reduced the immunoactivity of CD68 in the hippocampus of APP/PS1 mice. Running exercise inhibited TREM2 shedding and maintained TREM2 protein levels, which were accompanied by the promotion of brain glucose metabolism, microglial glucose metabolism and morphological plasticity in the hippocampus of AD mice. Microglia might be a structural target responsible for the benefits of running exercise in AD. Promoting microglial glucose metabolism and morphological plasticity modulated by TREM2 might be a novel strategy for AD treatment.

Zhang SS ，Zhu L ，Peng Y ，Zhang L ，Chao FL ，Jiang L ，Xiao Q ，Liang X ，Tang J ，Yang H ，He Q ，Guo YJ ，Zhou CN ，Tang Y ... -  《Journal of Neuroinflammation》

Geniposidic acid ameliorates spatial learning and memory deficits and alleviates neuroinflammation via inhibiting HMGB-1 and downregulating TLR4/2 signaling pathway in APP/PS1 mice.

Geniposidic acid (GPA) is an extract from Eucommia ulmoides Oliv. Bark (Eucommiaceae). Accumulating evidences have reported GPA has anti-aging, anti-oxidative stress, anti-inflammatory and neurotrophic effects on neurons. However, whether GPA could alleviate memory deficits in Alzheimer's disease animal models is not clear. We aimed to investigate the effect of GPA treatment on cognitive performance, Aβ deposition and glial cells activation in the transgenic mouse model of AD. 6-7 months APP/PS1 mice were given GPA for 90 days; behavioral experiments were executed to estimate the memory and spatial learning abilities of mice, and the mechanism of neuroprotective effect of GPA was investigated with a focus on amyloid-β deposition, astrocytes and microglia activation and neuroinflammation. GPA treatment significantly improved the spatial learning and memory abilities and also decreased cerebral amyloid-β deposition in APP/PS1 mice. Via HE staining, we found that GPA could ameliorate histopathological changes in cerebrum. We also found that GPA treatment inhibited the activation of astrocytes and microglia, down-regulated the expression of pro-inflammatory cytokines and iNOS, and up-regulated the expression of anti-inflammatory cytokines and Arg-1. In addition, GPA down-regulated the gene expression of HMGB-1 receptors (TLR2, TLR4 and RAGE) then mediated MyD88, TRAF6 and phospho-ERK1/2, subsequently modulated the expression of key AP-1 and NF-κB family members (c-Fos, c-Jun and p65). The reversal of the pro-inflammatory state suggested GPA can serves as a multi-target candidate by alleviating Aβ deposition and neuroinflammation for the auxiliary therapy of Alzheimer's disease.

Zhou Z ，Hou J ，Mo Y ，Ren M ，Yang G ，Qu Z ，Hu Y ... -  《-》