TARDBP Mediates the MAP3K11/SLC3A2/GPX4 Axis in Alzheimer's Disease Rats by Enhancing KRAS mRNA Stability

Huangpu Tongqiao Capsules(HPTQC), with the functions of invigorating Qi and kidney, eliminating phlegm and removing blood stasis, have the effect of treating Alzheimer's disease(AD), but its mechanism needs further exploration. To explore the relationship between the therapeutic mechanism of HPTQC on Alzheimer's disease and EGFR-PLCγ signal pathway, 40 healthy male SD rats were selected and divided into 4 groups randomly: sham operation group(sham), model group(model), HPTQC group(HPTQC), and nimodipine group(NMP). AD rat model was established by intraperitoneal injection of D-galactose combined with an intracerebral injection of amyloid-β peptide(25-35). After 28 days of administration, Morris water maze test and HE staining showed that the learning and memory ability of AD rats were significantly decreased(P<0.01), and hippocampal neurons were obviously da-maged. However, HPTQC could improve the learning and memory ability of AD rats(P<0.05) and reduce the damage of hippocampal neurons. Immunofluorescence test results showed that the expression levels of EGFR and p-Tau in hippocampal CA1 region of AD rats were significantly increased(P<0.01), and HPTQC could reduce the expression of EGFR and p-Tau in hippocampus of AD rats(P<0.01). Western blot results showed that the protein expression levels of EGFR, PLCγ, IP3 R and p-Tau in hippocampus of AD rats were significantly increased(P<0.01), and HPTQC could reduce the protein expression of EGFR, PLCγ, IP3 R and p-Tau in AD rats(P<0.05). RT-PCR results showed that the mRNA levels of EGFR, PLCγ, IP3 R and Tau in hippocampus of AD rats were significantly increased(P<0.01), and HPTQC could reduce the mRNA levels of EGFR, PLCγ, IP3 R and Tau in AD rats(P<0.05). The results indicate that HPTQC can improve the learning and memory ability of AD rats, and its mechanism of action may be related to regulating EGFR-PLCγ signal pathway.

Neuroinflammation has important effects on cognitive functions in the pathophysiological process of Alzheimer's Disease (AD). In the current report, we determined the effects of microRNA-155 (miR-155) on the levels of IL-1β, IL-6 and TNF-α, and their respective receptors in the hippocampus using a rat model of AD. Real-time RT-PCR, ELISA and western blot analysis were used to examine the miR-155, PICs and PIC receptors. The Morris water maze and spatial working memory tests were used to assess cognitive functions. miR-155 was increased in the hippocampus of AD rats, accompanied by amplification of IL-1β, IL-6 and TNF-α. Intracerebroventricular infusion of miR-155 inhibitor, but not its scramble attenuated the increases of IL-1β, IL-6 and TNF-α and upregulation of their receptors. MiR-155 inhibitor also attenuated upregulation of apoptotic Caspase-3 in the hippocampus of AD rats. Notably, inhibition of miR- 155 or PIC receptors largely recovered the impaired learning performance in AD rat. We showed the critical role of miR-155 in regulating the memory impairment in AD rats likely via engagement of neuroinflammatory mechanisms, suggesting that miR-155 and its signaling molecules may present prospects in preventing and/or improving the development of the impaired cognitive functions in AD.

To discuss the value of 11C-PIB PET and 18F-FDG micro PET imaging in Alzheimer's disease (AD) rat model. The AD rat model was established by injection of Abeta1-40 into rat's hippocampus. Learning and memory function were estimated by the Morris water maze. Amyloid deposit and neuron loss were observed by Congo red staining and HE staining respectively. 11C-PIB PET and 18F-FDG micro PET scan were performed. Meanwhile the findings of PET imaging were compared with the results of behavior test and histology. The uptake of 18F-FDG in hippocampus of AD rat model group was lower than that of control group (P < 0.01). The Morris water maze showed that the escape latent period of rat model group was longer than that of control group (P < 0.01). Neuron loss was found in rat model brain. Thus the result of micro-PET imaging was matched with those of the Morris water maze and HE staining. 11C-PIB was specifically bound to beta-amyloid in rat model brain, the uptake of 11C-PIB in AD rat model was higher than that of control (P < 0.05). Abeta deposit was observed in Congo red staining so that the result of 11C-PIB Micro-PET imaging was matched with that of beta-amyloid deposition. 11C-PIB Micro-PET imaging shows the plaque deposition while 18F-FDG PET imaging reflects the change of glucose metabolism in hippocampus in AD rat model. And PET scan can be used to verify the successful establishment of AD model rat model.

To determine the influence of tanshinone on the levels of nitric oxide synthase (NOS) and acetylcholinesterase (AChE) in the brain of an Alzheimer's Disease (AD) rat model and on its potential therapeutic mechanism. 100 Male Sprague Dawley rats were divided into three groups: control group, model group and tanshinone treatment group. 10 microg A beta 1-42 was injected bilaterally into the dorsal lateral region of the dentate gyrus in the hippocampus of rats in the model and tanshinone treatment groups to prepare the AD models. 24h after modeling, tanshinone, 50mg/kg, was administered by gastric perfusion to rats in the tanshinone treatment group. Later, immunohistochemical assay and Western blot analysis were used to detect expression of neuronal NOS (nNOS) and inducible NOS (iNOS) in the rat hippocampus. Activity of AChE in each subregion (CA1 approximately CA4) of rats' hippocampus was determined by a histochemical technique. Expression of nNOS in the model group was down-regulated whereas iNOS was up-regulated. After A beta 1-42 injection, the number of AChE positive fibers in each subregion (CA1 approximately CA4) of the hippocampus was decreased compared with controls. With tanshinone administration, the changes were improved to varying degrees. Tanshinone modulates AChE and NOS proteins concentrations in the hippocampus of AD rats. This may have therapeutic potential in AD rats.

Neuroinflammation and oxidative stress have significant effects on cognitive deficiency in the pathophysiological development of Alzheimer's disease (AD). In the present study, we studied the influences of Ampelopsin (AMP) on proinflammatory cytokines (PICs, IL-1β, IL-6 and TNF-α), and products of oxidative stress 8-isoprostaglandin F2α (8-iso PGF2α, a product of oxidative stress); and 8-hydroxy-2'-deoxyguanosine (8-OHdG, a key biomarker of protein oxidation) in the hippocampus using a rat model of AD. ELISA was used to examine PICs and oxidative stress production; and western blotting to examine NADPH oxidase (NOXs). The Spatial working memory tests and Morris water maze were utilized to assess cognitive functions. We observed amplification of IL-1β, IL-6 and TNF-α as well as 8-iso PGF2α and 8-OHdG in the hippocampus of AD rats. AMP attenuated upregulation of PICs and oxidative stress production. AMP also inhibited NOX4 in the AD rat hippocampus. Notably, AMP mostly improved learning performance in AD rat and this was linked to signal pathways of PIC and oxidative stress. AMP plays a significant role in improving the memory deficiency in AD rats via inhibition of signal pathways of neuroinflammation and oxidative stress, suggesting that AMP is likely to prospect in preventing and relieving development of the cognitive dysfunctions in AD as a complementary alternative intervention.

Baicalin has been shown to promote spatial learning and neural regeneration, which might increase the differentiation of neural stem cells in Alzheimer's disease (AD) rat models. We aimed to study the role of baicalin on neuronal pentraxin-1 (NPTX-1), neuronal pentraxin-2 (NPTX-2), and C-reactive protein (CRP) in AD model rats. The 30 male Sprague Dawley rats were divided into three groups: the control group, the AD model group, and the AD + baicalin group. Then, the Morris water maze was used to verify the effect of baicalin on the memory and spatial learning of rats. Immunohistochemistry and immunofluorescence were used to observe the expression of NPTX-1, NPTX-2, and CRP in brain tissue. Compared with the AD model group, the AD rats treated with baicalin spent significantly less time finding escape latencies (P = 0.008) and had longer cross-platform times in the target quadrant (P = 0.015). In addition, the AD + baicalin group had significantly higher numbers of hippocampal neurons compared with the AD model group (P < 0.05). Baicalin also obviously decreased the apoptosis of neurons. Moreover, compared with the AD model group, the NPTX-1 and CRP expression in the AD + baicalin group was significantly reduced (P = 0.000) while the expression of NPTX-2 in the brain tissue of AD rats was significantly increased (P = 0.000). Baicalin can play a therapeutic role by downregulating NPTX-1, upregulating NPTX-2, and downregulating CPR in AD model rats.

Nitric oxide impairs spatial learning and memory in a rat model of Alzheimer’s disease via disturbance of glutamate response in the hippocampal dentate gyrus during spatial learning

Objective To explore the roles of vascular endothelial growth factor (VEGF) and P38MAPK in the pathogenesis of Alzheimer's disease(AD) rats,and the effects of butyIphthalide on the influence of VEGF and P38MAPK in hippocampus of AD rats.Methods SD rats were randomly divided into blank group,AD model group,butylphthalide low-dose group and high dose group (n =8 rats per group).Aggregated Aβ1-42 was injected into the bilateral hippocampus of rats by stereotaxic coordinates method to induce AD.Morris water maze test was used to determine the abilities of learning and memory.Western blotting combined with Gel Doc imagine systems were used to investigate the expression of VEGF and P-P38MAPK in hippocampus of AD rats.Results The result of Morris water maze experiment showed that one week after modeling,escape latency was different(F =66.658,P ＜ 0.05),and either dose the frequency of crossing platform (F =6.884,P ＜0.05).Compared with the blank group,the other three groups'latent period of escape was extended significantly(P ＜ 0.05),and frequency of crossing platform was significantly less (P ＜ 0.05).After drug intervention for 4 weeks,the expression of VEGF was difference(F =171.064,P ＜0.05),it was decreased obviously in the model group than blank group(P ＜=0.05),but it was increased in the drug intervention groups than model group (P ＜ 0.05),and increased more significantly in the high dose group than low dose group (P ＜ 0.05).The expression of P38MAPK had no obvious change among four groups (P ＞ 0.05),however,the expression of P-P38MAPK showed difference(F =104.395,P ＜ 0.05),it was increased in drug intervention and model group than blank group (P ＜ 0.05),it was increased in drug intervention and model group than blank group (P ＜ 0.05),reduced significantly in drug intervention groups than model group (P ＜ 0.05),and decreased more significantly in high dose groups than low dose group (P ＜ 0.05).Conclusions Butylphthalide could obviously enhance the expression of VEGF,reduce the expression of P-P38MAPK in hippocampus of AD rats. Key words: Propiophenones/pharmacology; Alzheimer disease; Vascular endothelial growth factors; p38 mitogen-activated protein kinases

Ginkgo biloba extracts (GBE) have been shown to effectively improve cognitive function in patients with Alzheimer's disease (AD). One potential therapeutic strategy for AD is to prevent loss of adult hippocampal neurons. While recent studies have reported that GBE protects against oxidative stress in neurons, the underlying mechanisms remain unclear. In this study, an AD-like rat model was established via bidirectional injection of amyloid beta 25-35 (Aβ25-35; 20 μg) in the hippocampal CA1 region. Learning and memory abilities of experimental rats were AD assessed in response to oral administration of 7.5 g/L or 15 g/L Ginkgo biloba extract 50 (GBE50) solution and the peroxidation phenomenon of hippocampal mitochondria determined via analysis of mitochondrial H2O2 and several related enzymes. Levels of the oxidative stress-related signaling factor cytochrome C (Cyto C), apoptosis-related proteins (Bax, Bcl-2 and caspase-3) and caspase-activated DNase (CAD) were further detected via western blot. 8-Hydroxydeoxyguanosine (8-OHdG), the major product of DNA oxidative stress, was evaluated to analyze DNA status. Our results showed elevated H2O2 levels and monoamine oxidase (MAO) activity, and conversely, a decrease in the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the hippocampus of AD rats. Administration of GBE50 regulated the activities of these three enzymes and induced a decrease in H2O2. GBE50 exerted regulatory effects on abnormally expressed apoptotic proteins in the AD rat hippocampus, enhancing the expression of Bcl-2, inhibiting release of Cyto C from mitochondria, and suppressing the level of caspase-3 (excluding cleaved caspase-3). Furthermore, GBE50 inhibited DNA damage by lowering the generation of 8-OHdG rather than influencing expression of CAD. The collective findings support a protective role of GBE50 in hippocampal neurons of AD-like animals against mitochondrial oxidative stress.

Schisandra chinensis (Turcz.) Baill is produced mainly in northeast China, Korea and Japan. Its fruit has been used in food as a nutritional and functional ingredient for centuries. Polysaccharide is an important chemical component in Schisandra. Previous studies have shown that Schisandra polysaccharide (SCP) could be used to improve cognitive function clinically and treat age-related neurodegenerative disorders. In this study, a urinary metabolomics method based on ultra-high-performance liquid chromatography combined with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) was established to investigate the change of endogenous metabolites in an amyloid β-protein (Aβ) 25-35-induced Alzheimer's disease (AD) rat model. Meanwhile, levels of 9 neurotransmitters were evaluated with ultrahigh-performance liquid chromatography-triple-quadrupole mass spectrometry (UHPLC-TQ-MS) to explore the therapeutic mechanisms of SCP on the AD rat model. Additionally, the synthesis of phosphorylated tau protein (p-tau), acetylcholinesterase (AchE) activity and oxidative damage in the brain of the AD rats were assessed using glycogen synthase kinase-3β (GSK3β), AchE and antioxidant assays, NOS (nitric oxide synthase) and SOD (superoxide dismutase), respectively. The results indicated that the AD model was established successfully and the inducement of Aβ25-35 caused the phosphorylation of tau protein and the deposition of Aβ. In the AD model rats, the levels of AchE, GSK-3β and NOS were significantly elevated and SOD activity was reduced. In the hippocampus of the model rats, the contents of γ-aminobutyric acid, acetylcholine, glycine, norepinephrine, taurine, serotonin and dopamine were significantly decreased and the contents of glutamate and aspartic acid were increased significantly. However, SCP could reduce the degree of phosphorylation of tau protein, the deposition of Aβ and oxidative damage and reverse these changes of neurotransmitters in the AD rats. In a metabolomics study, a total of 38 metabolites were finally identified as potential biomarkers of AD and all of them had a significant recovery compared with the AD model after SCP administration. Metabolomics studies have shown that SCP plays a role in protecting the central nervous system, regulating intestinal microbial metabolism, regulating energy metabolism, and promoting antioxidant effects by regulating the levels of endogenous metabolites in related pathways. This is first report of the use of urine metabolomics combined with the evaluation of 9 neurotransmitter levels to investigate the mechanism of SCP on the treatment of AD.

The study of therapeutic efficacy and mechanisms of Schisandra chinensis and Evodia rutaecarpa combined treatment in a rat model of Alzheimer's disease

Assessment of ultrasonic vocalization-mediated communication deficits in AD rats: A social learning paradigm using conspecific drinking behavior.

An integrative study on the effects of Lingguizhugan decoction in treating Alzheimer's disease rats through modulation of multiple pathways involving various components.

Alzheimer's disease (AD) is one of the most important neurodegenerative disorders. It is characterized by dementia including deficits in learning and memory. The present study aimed to evaluate the effects of aqueous extract of lavender (Lavandula angustifolia) on spatial performance of AD rats. Male Wistar rats were first divided into control and AD groups. Rat model of AD was established by intracerebroventricular injection of 10 μg Aβ1-42 20 d prior to administration of the lavender extract. Rats in both groups were then introduced to 2 stages of task learning (with an interval of 20 d) in Morris water maze, each followed by one probe test. After the first stage of spatial learning, control and AD animals received different doses (50, 100 and 200 mg/kg) of the lavender extract. In the first stage of experiment, the latency to locate the hidden platform in AD group was significantly higher than that in control group. However, in the second stage of experiment, control and AD rats that received distilled water (vehicle) showed similar performance, indicating that the maze navigation itself could improve the spatial learning of AD animals. Besides, in the second stage of experiment, control and AD rats that received lavender extract administration at different doses (50, 100, and 200 mg/ kg) spent less time locating the platform (except for the AD rats with 50 mg/kg extract treatment), as compared with their counterparts with vehicle treatment, respectively. In addition, lavender extract significantly improved the performance of control and AD rats in the probe test, only at the dose of 200 mg/kg, as compared with their counterparts with vehicle treatment. The lavender extract can effectively reverse spatial learning deficits in AD rats.

The effect of levothyroxine (L-T4) on the learning and memory impairment induced by streptozotocin (STZ) and brain tissue oxidative damage in rats was evaluated. An animal model of the Alzheimer’s disease (AD) was established by intracerebroventricular injection of STZ (3 mg/kg) in male Wistar rats (250 ± 50 g). After that, the rats were treated for 3 weeks with L-T4 (10, 100 μg/kg) or normal saline. Passive avoidance (PA) learning and spatial memory were evaluated using shuttle box and Morris water maze (MWM), respectively. Finally, the rats were euthanized, their blood samples were collected for further thyroxine assessment and their brains were removed after decapitation in order to measure the oxidative stress parameters and brain-derived neurotrophic factor (BDNF). In the MWM, latency (s) increased in the AD rats compared with the normal control group while it decreased in the 10 μg/kg L-T4 injected AD rats compared with the AD group. In the PA, the latency for entering the dark compartment was lower in the AD group than in the normal control group and it decreased in the 10 μg/kg L-T4 injected AD rats. The low dose of L-T4 (10 μg/kg) reduced malondialdehyde concentration but increased thiols concentration, superoxide dismutase, catalase activities and BDNF level in hippocampal tissues of the AD rats. Injection of L-T4 (10 μg/kg) alleviated memory deficits and also improved factors of oxidative stress and BDNF level in the STZ-induced AD rats.