The Mechanism by Which LiCl Attenuates the Impaired Ability of Learning and Memory of APP/PS1 Double Transgenic Mice May Involve Elevating the Expression of a7 Nicotinic Acetylcholine Receptors via Regulation of the Wnt/β-catenin Pathway

Author(s):  
Xiang Jie ◽  
Ran Long Yan ◽  
Zeng Xiao Xiao ◽  
He Wen Wen ◽  
Xu Yi ◽  
...  

Abstract BackgroundWe examined the mechanism by which lithium chloride (LiCl) attenuates the impaired learning and memory of APP/PS1 double transgenic (APP/PS1) mice. MethodsSix- or twelve-month-old APP/PS1 and wild-type (WT) mice were divided randomly into 4 groups: WT, WT+Li (100 mg LiCl/kg body weight, gavage once daily), APP/PS1 and APP/PS1+Li. Primary rat hippocampal neurons were exposed to β-amyloid peptide oligomers (AβOs), LiCl and/or XAV939 (inhibitor of Wnt/β-catenin) or transfected with small interfering RNA against the β-catenin gene. Phosphor-glycogen synthase kinase-3β (GSK3β) (ser9), total GSK3β, β-catenin, cyclin D1, and α7 nAChR protein and mRNA were quantified by Western blotting or real-time PCR, respectively; senile plaques and α7 protein by immunohistochemical or immunofluorescent staining; Aβ 42 by ELISA; and cell viability by CCK8. Learning and memory were assessed utilizing the Morris water maze test. ResultsIn the brains of APP/PS1 mice, the level of Aβ was increased and those of α7 nAChR, phosphor-GSK3β (ser9), β-catenin, and cyclin D1 (at the protein and/or mRNA level) reduced. Treatment with LiCl for 2 months at 4 or 10 months of age attenuated all of these effects. Similar changes in the levels of these proteins were observed in primary neurons exposed to AβOs and these effects were attenuated by LiCl and aggravated by XAV939. Inhibition of β-catenin expression lowered the level of α7 nAChR protein in these cells. ConclusionLiCl attenuates the impaired ability of learning and memory of APP/PS1 mice via a mechanism that might involve elevation of the level of α7 nAChR as a result of altered Wnt/β-catenin signaling.

2020 ◽  
Vol 15 (3) ◽  
pp. 1934578X1990068
Author(s):  
Shu Jing ◽  
Cong Liu ◽  
Huijiao Lin ◽  
Xinyun Zhang ◽  
Fei Wang ◽  
...  

Memory disorders are the main symptoms of aging and Alzheimer’s disease and seriously affect the quality of life. Schisandra, as a famous traditional Chinese medicine, has been used for modulating “the internal organs” for a thousand years. The total lignans from Schisandra have been scientifically proved to improve learning and memory ability. Since it is unclear which monomer in Schisandra total lignans exerts such a function, we evaluated the potential effects of Schisantherin A (SCA), the main monomer from Schisandra, on improving learning ability and memory in amyloid β-protein (Aβ1-42)-induced Alzheimer’s disease (AD) model mice. We found that SCA (5 mg/kg) significantly prolonged the latency and reduced the number of errors in a step-through test. SCA significantly shortened the time of finding the platform and increased the number of crossing the platform and the residence time in a Morris water maze test. SCA increased superoxide dismutase activities and reduced the Malondialdehyde level of the hippocampal tissue, suggesting its role in reducing oxidative stress in the AD mice. Furthermore, we found that SCA significantly decreased the hyperphosphorylation of Tau by altering glycogen synthase kinase-3β (GSK-3β) phosphorylation on Tyr216 and Ser9. Our results revealed the mechanism underlying SCA-mediated learning and memory improvement by regulating GSK-3β activity and lowering the hyperphosphorylation of Tau protein in the hippocampus of AD mice.


Acta Naturae ◽  
2018 ◽  
Vol 10 (3) ◽  
pp. 57-61 ◽  
Author(s):  
M. L. Bychkov ◽  
N. A. Vasilyeva ◽  
M. A. Shulepko ◽  
P. M. Balaban ◽  
M. P. Kirpichnikov ◽  
...  

Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels. Many neurodegenerative diseases are accompanied by cognitive impairment associated with the dysfunction of nAChRs. The human membrane-tethered prototoxin Lynx1 modulates nAChR function in the brain areas responsible for learning and memory. In this study, we have demonstrated for the first time that the -amyloid peptide A1-42 decreases Lynx1 mRNA expression in rat primary cortical neurons, and that this decrease is associated with the activation of c-Jun N-terminal kinase (JNK). In addition, we have demonstrated that the Lynx1 expression decrease, as well as the blockade of the long-term potentiation underlying learning and memory, caused by A1-42, may be prevented by incubation with a water-soluble Lynx1 analogue. Our findings suggest that the water-soluble Lynx1 analogue may be a promising agent for the improvement of cognitive deficits in neurodegenerative diseases.


2020 ◽  
Vol 23 (5) ◽  
pp. 402-410 ◽  
Author(s):  
Lin-Zi Li ◽  
Shan-Shan Lei ◽  
Bo Li ◽  
Fu-Chen Zhou ◽  
Ye-Hui Chen ◽  
...  

Aim and Objective: The Dendrobium officinalis flower (DOF) is popular in China due to common belief in its anti-aging properties and positive effects on “nourish yin”. However, there have been relatively few confirmatory pharmacological experiments conducted to date. The aim of this work was to evaluate whether DOF has beneficial effects on learning and memory in senescent rats, and, if so, to determine its potential mechanism of effect. Materials and Methods: SD rats were administrated orally DOF at a dose of 1.38, or 0.46 g/kg once a day for 8 weeks. Two other groups included a healthy untreated control group and a senescent control group. During the 7th week, a Morris water maze test was performed to assess learning and memory. At the end of the experiment, serum and brain samples were collected to measure concentrations of antioxidant enzymes, including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GSH-Px) in serum, and the neurotransmitters, including γ-aminobutyric acid (γ-GABA), Glutamic (Glu), and monoamine oxidase B (MAO-B) in the brain. Histopathology of the hippocampus was assessed using hematoxylin-eosin (H&E) staining. Results: The results suggested that treatment with DOF improved learning as measured by escape latency, total distance, and target quadrant time, and also increased levels of γ-GABA in the brain. In addition, DOF decreased the levels of MDA, Glu, and MAO-B, and improved SOD and GSHPx. Histopathological analysis showed that DOF also significantly reduced structural lesions and neurodegeneration in the hippocampus relative to untreated senescent rats. Conclusion: DOF alleviated brain aging and improved the spatial learning abilities in senescent rats, potentially by attenuating oxidative stress and thus reducing hippocampal damage and balancing the release of neurotransmitters.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dan Song ◽  
Yaohua Chen ◽  
Cheng Chen ◽  
Lili Chen ◽  
Oumei Cheng

Abstract Purpose and background Previous studies have suggested that promoting endogenous neurogenesis has great significance for the recovery of cognitive dysfunction caused by cerebral ischemia (CI). Pharmacological inhibition of GABAB receptor can enhance neurogenesis in adult healthy and depressed mice. In the study, we intended to investigate the effects of GABAB receptor antagonists on cognitive function and hippocampal neurogenesis in mice following CI. Methods Adult mice were subjected to bilateral common carotid artery occlusion (BCCAO) for 20 min to induce CI and treated with CGP52432 (antagonist of GABAB receptor, CGP, 10 mg/kg intraperitoneal injection) starting 24 h after CI. The Morris water maze test was performed to test spatial learning and memory at day 28. Immunofluorescence was applied to detect neurogenesis in the DG region at day 14 and 28. In in vitro experiments, cell proliferation was detected by CCK8 and immunofluorescence, and the expression of cAMP/CREB signaling pathway-related proteins was detected by ELISA assay and Western blot. Results CGP significantly improved spatial learning and memory disorders caused by CI, and it enhanced the proliferation of neural stem cells (NSCs), the number of immature neurons, and the differentiation from newborn cells to neurons. In vitro experiments further confirmed that CGP dose-dependently enhanced the cell viability of NSCs, and immunofluorescence staining showed that CGP promoted the proliferation of NSCs. In addition, treatment with CGP increased the expression of cAMP, PKA, and pCREB in cultured NSCs. Conclusion Inhibition of GABAB receptor can effectively promote hippocampal neurogenesis and improve spatial learning and memory in adult mice following CI.


2021 ◽  
pp. 1-9
Author(s):  
Guizhen Liu ◽  
Yuchuan Sun ◽  
Fei Liu

<b><i>Objective:</i></b> The purpose of this study was to explore the role of curcumin (Cur) in isoflurane (ISO)-induced learning and memory dysfunction in Sprague-Dawley rats and further elucidate the mechanism of the protective effect produced by Cur. <b><i>Methods:</i></b> Rat models of cognitive impairment were established by inhaling 3% ISO. The Morris water maze test was used to assess the cognitive function of rats. ELISA and qRT-PCR were used to analyze the protein levels of pro-inflammatory cytokines and expression levels of miR-181a-5p, respectively. <b><i>Results:</i></b> Cur significantly improved the ISO-induced cognitive dysfunction in rats and alleviated the ISO-induced neuroinflammation. miR-181a-5p was overexpressed in ISO-induced rats, while Cur treatment significantly reduced the expression of miR-181a-5p. Overexpression of miR-181a-5p promoted the cognitive impairment and the release of inflammatory cytokines and reversed the neuroprotective effect of Cur. <b><i>Conclusion:</i></b> Cur has a protective effect on ISO-induced cognitive dysfunction, which may be achieved by regulating the expression of miR-181a-5p.


2010 ◽  
Vol 104 (9) ◽  
pp. 1297-1303 ◽  
Author(s):  
Yan-Hong Huang ◽  
Qing-Hong Zhang

The present study was undertaken to investigate the antioxidant effect of chronic ingestion of genistein (Gen) against neural death in the brain of ovariectomised (Ovx) rats. The rats were randomly divided into five groups, i.e. sham-operated (sham), Ovx-only, Ovx with 17β-oestradiol, Ovx with low (15 mg/kg) and high (30 mg/kg) doses of Gen (Gen-L and Gen-H), and were orally administered daily with drugs or vehicle for 6 weeks. The learning and memory abilities were measured by Morris water maze test. Oxidative damages in the brain were evaluated by the level of superoxide dismutase (SOD), malondialdehyde (MDA) and monoamine oxidase (MAO) activities. Neural apoptosis was shown by terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) staining and caspase-3 activity. In the visual learning and memory test, there were no significant differences among the population means of the five groups. While in the probe trial test, the Gen-L group instead of the Gen-H group exhibited reduced escape latency and increased memory frequency than the Ovx group. Although both doses of Gen could reduce acetylcholinesterase activity, only a low dose of Gen could diminish MDA activity significantly in frontal cortex and enhance SOD content in the hippocampus. In contrast, MAO content was decreased in the cortex by either dose of Gen, while in the hippocampus, only a high dose of Gen appeared to be effective. Interestingly, Gen at both the doses could attenuate the increased number of TUNEL-positive neurons and caspase-3 activity in Ovx rats. These results suggest that Gen confers protection against Ovx-induced neurodegeneration by attenuating oxidative stress, lipid peroxidation and the mitochondria-mediated apoptotic pathway in a region- and dose-dependent manner.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Gil-Yong Lee ◽  
Chan Lee ◽  
Gyu Hwan Park ◽  
Jung-Hee Jang

Increasing evidence suggests that neurodegenerative disorders such as Alzheimer’s disease (AD) are mediated via disruption of cholinergic neurons and enhanced oxidative stress. Therefore, attention has been focused on searching for antioxidant phytochemicals for the prevention and/or treatment of AD through their ability to fortify cholinergic function and antioxidant defense capacity. In this study, we have investigated the neuroprotective effect ofα-pinene (APN) against learning and memory impairment induced by scopolamine (SCO, 1 mg/kg, i.p.), a muscarinic receptor antagonist in C57BL/6 mice. Administration of APN (10 mg/kg, i.p.) significantly improved SCO-induced cognitive dysfunction as assessed by Y-maze and passive avoidance tests. In Morris water-maze test, APN effectively shortened the mean escape latency to find the hidden platform during training days. To further elucidate the molecular mechanisms underlying the neuroprotective effect of APN, the expression of proteins involved in the acetylcholine metabolism and antioxidant system was examined. Particularly, APN treatment increased mRNA expression of choline acetyltransferase in the cortex and protein levels of antioxidant enzymes such as heme oxygenase-1 and manganese superoxide dismutase in the hippocampus via activation of NF-E2-related factor 2. These findings suggest the possible neuroprotective potentials of APN for the management of dementia with learning and memory loss.


2021 ◽  
Vol 19 ◽  
Author(s):  
Tingting Pi ◽  
Guangping Lang ◽  
Bo Liu ◽  
Jingshan Shi

Background: High methionine-diet (HMD) causes Alzheimer's disease (AD)-like symptoms. Previous studies have shown that Dendrobium nobile Lindle. alkaloids (DNLA) had potential benefits for AD. Object: Whether DNLA can improve AD-like symptoms induced by HMD is to be explored. Method: Mice were fed with 2% HMD diet for 11 weeks, the DNLA20 control group (20 mg/kg), DNLA10 group (10 mg/kg), and DNLA20 group (20 mg/kg) were administrated with DNLA for 3 months. Morris water maze test was used to detect learning and memory ability. Neuron damage was evaluated by HE and Nissl stainings. Levels of homocysteine (Hcy), beta-amyloid 1-42 (Aβ1-42), S-adenosine methionine (SAM), and S-adenosine homocysteine (SAH) were detected by ELISA. Immunofluorescence and western blotting (WB) were used to determine the expression of proteins. CPG island methylation. Results: Morris water maze test revealed that DNLA improved learning and memory dysfunction. HE, Nissl, and immunofluorescence stainings showed that DNLA alleviated neuron damage and reduced the 5-methylcytosine (5-mC), Aβ1-40, and Aβ1-42 levels. DNLA also decreased the levels of Hcy and Aβ1-42 in the serum, along with decreased SAM/SAH levels in the liver tissue. WB results showed that DNLA down-regulated the expression of the amyloid-precursor protein (APP), presenilin-1 (PS1), beta-secretase-1 (BACE1), DNA methyltransferase1 (DNMT1), Aβ1-40, and Aβ1-42 proteins. DNLA also up-regulated the expression of the protein of insulin-degrading enzyme (IDE), neprilysin (NEP), DNMT3a, and DNMT3b. Meanwhile, DNLA increased CPG island methylation levels of APP and BACE1 genes. Conclusions: DNLA alleviated AD-like symptoms induced by HMD via the DNA methylation pathway.


Author(s):  
Xiaoling Wu ◽  
Zhiqin Yang ◽  
Huimin Dang ◽  
Huixia Peng ◽  
Zhijun Dai

Baicalein, a flavonoid derived from the root of Scutellaria baicalensis, has been reported to possess multiple pharmacological activities, such as anticancer and anti-inflammatory properties. This study investigated the effect of baicalein in cervical cancer cells. Cell growth curve and MTT assay were performed and revealed that baicalein inhibited the proliferation of SiHa and HeLa cells in a dose-dependent manner. We further found that baicalein arrested the cell cycle of SiHa and HeLa cells at the G0/G1 phase by suppressing the expression of cyclin D1 through the downregulation of phosphorylated protein kinase B (p-AKT) and phosphorylated glycogen synthase kinase 3β (p-GSK3β) according to FACS assays and Western blotting. Moreover, when CHIR-99021, a GSK3β inhibitor, was added to baicalein-treated SiHa cells, the expression of cyclin D1 was recovered, and cell proliferation was promoted. In conclusion, these data indicated that baicalein suspended the cell cycle at the G0/G1 phase via the downregulation of cyclin D1 through the AKT‐GSK3β signaling pathway and further inhibited the proliferation of SiHa and HeLa cervical cancer cells.


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