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Background: Osthole, a natural coumarin, found in many medicinal plants. Previous studies have shown its neuroprotective effects, whereas the effect and fundamental mechanism of Osthole for alleviating AD-associated dysmnesia is still not fully clear. Purpose: This study aimed to examine the neuroprotection of Osthole against cognitive impairment in the D-galactose-induced rats and its pharmacological mechanism. Method: The rat was constructed by subcutaneous injection of D-galactose at a dose of 150 mg/kg/day for 56 days as a model. The effect of Osthole on cognitive impairment was evaluated by behavior and biochemical analysis. Subsequently, a combination of in silico prediction and experimental validation was performed to determine the underlying mechanisms of Osthole against Alzheimer's disease, while to verify the network-based predictions, western blot, Nissl staining, and immunofluorescence were applied. Result: Osthole could improve memory dysfunction induced by D-galactose in Sprague Dawley male rat. Endophenotype-based network approach highlight several AD-related pathological processes that may be regulated by Osthole, including neuronal apoptosis, neuroinflammationand endoplasmic reticulum stress. Among them, the proapoptotic markers (Bax), antiapoptotic protein (Bcl-2), moreover, the microgliosis (Iba-1), Astrocytosis (GFAP), and inflammatory cytokines (TNF-α1), levels of ER stress-associated proteins (BIP, p-PERK/PERK, Caspase12, CHOP and XBP1s) were evaluated in both hippocampus and cortex. And the results indicated that Osthole significantly ameliorated neuronal apoptosis, neuroinflammation and ER stress in D-galactose induced rats. Conclusion: This study explored the pharmacological mechanism of Osthole against D-galactose induced memory impairment and identified Osthole as a potential anti-AD drug candidate targeting multiple signaling pathways by endophenotype network-based.

Background Alzheimer's disease (AD) is a neurodegenerative disease characterised with signature pathological lesions of extracellular senile plaques and intracellular neurofibrillary tangles comprising amyloid beta (Aβ) protein and hyperphosphorylated tau protein, respectively. Microglia, the major players of innate immune cells in the brain, can cleave Aβ via phagocytosis and autophagy. Methods To examine the effects of EGCG on the cognitive deficit of APP/PS1 mice, behavioural tests such as open-field test and Y-maze were performed and hippocampus tissues were collected for Immunofluorescence assay after EGCG treatment. We estimated expression levels of various related proteins by western blot to evaluate the role of EGCG in AD progression. To investigate whether EGCG protects SH-SY5Y cells following microglial cell-mediated clearance of Aβ1−42, we performed a co-culture experiment with SH-SY5Y cells and N9 microglia. Results Our results demonstrate that epigallocatechin-3-gallate (EGCG), a major green tea phytochemical, could improve the learning and memory abilities of AD mice, erase Aβ deposition, and promote microglial proliferation. The EGCG-induced Aβ clearance by microglia is mediated through the blockade of the histone deacetylase 6 (HDAC6), phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway and the subsequent activation of autophagy. EGCG protects neuronal cells from Aβ1−42-mediated toxicity through the clearance of Aβ by microglia. Conclusion Our work describes an EGCG-HDAC6-PI3K/AKT/mTOR signalling axis that influences microglial autophagy, and suggests that the therapeutic targeting of this axis could enhance the cognitive function in AD by Aβ clearance.

Background As a major risk factor for neurodegenerative diseases, aging has become a heavy health care burden worldwide. Age-related decline in mitochondrial function and oxidative stress is strongly associated with neurodegeneration. The previous study demonstrated that Bushen-Yizhi formula (BSYZ), a traditional Chinese medicine formula, is effective in reducing neurodegeneration. Methods This study is the first to investigate the effect of BSYZ on D-gal-induced learning memory in rats. Secondly, the potential metabolic mechanism of BSYZ was explored by 1H-NMR metabolomics analysis. Then based on the comparison of differential metabolites implied that BSYZ ameliorated mitochondrial dysfunction through choline metabolic pathway in D-gal-treated rats. Finally, pharmacological validation was conducted to explore the effects of BSYZ on D-gal-induced oxidative stress, neuroinflammation, and neuronal apoptosis. Results Our data showed that BSYZ increased aspartate and betaine levels, while decreasing choline levels. Furthermore, BSYZ also increased the proteins level of CHDH and BHMT to regulate choline metabolic pathway. Meanwhile, BSYZ alleviated mitochondrial damage and oxidative stress, including enhanced ATP production and the ratio of NAD+/NADH, reduced the level of MDA, enhanced GSH and SOD activity, upregulated the expressions of p-AMPK, SIRT1 proteins. In addition, BSYZ downregulated the levels of inflammatory cytokines, such as TNF-α, IL-1β and IL-6, as well as suppressed Bcl-2 proteins family dependent apoptosis. Conclusion BSYZ treatment effectively rescues neurobehavioral impairment by improving mitochondrial dysfunction, oxidative stress, neuroinflammation and neuroapoptosis via AMPK/SIRT1 pathway in D-gal-induced aging.