Genistein Inhibits Aß25-35-Induced Synaptic Toxicity and Regulates CaMKII/CREB Pathway in SH-SY5Y Cells.

Genistein (Gen), as a functional food in human diet, has shown many beneficial effects on neurodegenerative diseases such as Alzheimer's disease (AD). But the neuroprotective mechanism of Gen is not clear. Because synaptic failure is considered as the earliest phase in the pathogenesis of AD, we try to validate our hypothesis that synapse may be one target of Gen on protecting neurons. In this study, SH-SY5Y cells were pre-incubated with or without Gen for 2 h followed by the incubation with Aß25-35 (25 µmol/L) for another 24 h. Flow cytometry, Western Blots, and RT-PCR analysis were used to test the synaptic factors. The data showed that Gen pre-treatment could reverse the Aß25-35-induced down-regulation of synaptophysin and postsynaptic marker postsynaptic density-95. In addition, the down-regulation of NR1 and NR2B induced by Aß25-35 which are subunits of N-methyl-D-aspartate receptor also could be antagonized by pre-treatment of Gen. Moreover, the factors of CaMKII/CREB signaling pathway were detected. The results showed that mRNA and protein expressions of (Ca(2+))/calmodulin(CaM), CaMKII/pCaMKII, and CREB/pCREB were significantly down-regulated by Aß25-35, but they were all restored by the pre-treatment of Gen. Furthermore, Gen also maintained the intracellular Ca(2+) concentration which was disturbed by Aß25-35. In conclusion, these results suggested that Gen could protect synaptic dysfunction induced by Aß, and the mechanism might be associated with the regulation of synaptic markers and Ca(2+) level through activating CaM/CaMK/CREB signaling pathway.

Global DNA methylation was changed by a maternal high-lipid, high-energy diet during gestation and lactation in male adult mice liver.

An epigenetic mechanism has been suggested to explain the effects of the maternal diet on the development of disease in offspring. The present study aimed to observe the effects of a maternal high-lipid, high-energy (HLE) diet on the DNA methylation pattern of male offspring in mice. Female C57BL/6J mice were fed an HLE diet during gestation and lactation. The genomic DNA methylations at promoter sites of genes in the liver, mRNA and protein levels of selected genes related to lipid and glucose metabolism were measured by microarray, real-time PCR and Western blot. The results indicated that the percentage of methylated DNA in offspring from dams that were fed an HLE diet was significantly higher than that from dams that were fed a chow diet, and most of these genes were hypermethylated in promoter regions. The nuclear protein content and mRNA levels of hypermethylated genes, such as PPARγ and liver X receptor α (LXRα), were decreased significantly in offspring in the HLE group. The results suggested that the DNA methylation profile in adult offspring livers was changed by the maternal HLE diet during gestation and lactation.

Soy isoflavone antagonizes the oxidative cerebrovascular injury induced by ß-amyloid peptides 1-42 in rats.

Numerous evidences have shown that the antioxidative properties of soy isoflavone (SIF) have beneficial effects on prophylaxis of neurodegeneration, however, the mechanism is still not fully illustrated. As cerebrovascular dysfunction could initiate a cascade of events leading to pathogenesis of Alzheimer's disease, we tried to investigate whether SIF could protect the cerebrovascular system due to antagonizing oxidative damage induced by Aß1-42 in present study. In addition, NF-E2-related factor 2 (Nrf2) signaling pathways in the cerebrovascular tissue of Wistar rats were investigated to identify the potential cerebrovascular protective targets of SIF. Research results showed that SIF reduced the excessive production of nitrotyrosine in cerebrovascular tissue induced by Aß1-42, and maintained redox homeostasis by increasing the level of GSH and GSH/GSSG. Moreover, SIF could alleviate the down-regulation of Nrf2, γ-glutamylcysteine synthetase, Heme oxygenase-1 expressions in cerebrovascular tissue induced by Aß1-42 and suppress the increase of Kelch like ECH protein-1 (Keap1). These data suggested that SIF might reduce the cerebrovascular oxidative damage induced by Aß1-42 through regulating the Nrf2 signaling pathway. The mechanisms of SIF modulating the potential target Nrf2 might be associated with Keap1 expression.

Association of leptin gene -2548 G/A polymorphism with obesity: a meta-analysis.

BACKGROUND: A common single-nucleotide polymorphism identified in the 5'-untranslated region of the leptin gene (LEP -2548 G/A polymorphism) may be associated with obesity, but the existing research findings are inconsistent, so we conducted this meta-analysis. METHODS: Medline, Embase and ISI Web of Science databases were searched to identify relevant studies. Meta-analysis of the total and subgroup populations was conducted using allelic, additive, dominant and recessive models, and odds ratios and their 95% confidence intervals were calculated in a fixed-effect model if no heterogeneity (evaluated as I(2) statistic) existed. Otherwise, a random-effects model was adopted. Subgroup analysis was performed by ethnicity. Meta-regression and the HETRED analysis were used to explore the potential sources of between-study heterogeneity. Egger's test and influence analysis were conducted to evaluate the publication bias and study power, respectively. RESULTS: The final selection enrolled 9 studies, including 2,988 subjects (1,372 obese subjects and 1,616 controls). No significant association was identified between the LEP -2548 G/A polymorphism and obesity for all genetic models in the overall population and Caucasians. We found a significant association with allelic, additive and dominant models for subjects of mixed race from South America. Notwithstanding, this significance should be treated cautiously for it is based on a rather small sample (788 involved subjects). CONCLUSIONS: In total, the combined analysis of data from current and published studies suggested that the LEP -2548 G/A polymorphism does not contribute to the development of obesity, despite the fact that a significant association exists in a small subgroup from South America. Further studies are needed to elucidate the relationship. .

Soy isoflavone attenuates brain mitochondrial oxidative stress induced by ß-amyloid peptides 1-42 injection in lateral cerebral ventricle.

The aim of this study is to investigate whether soy isoflavone (SIF) reduces oxidative stress and improves the antioxidant ability in mitochondria of rat brain damaged by injection of beta-amyloid peptides 1-42 (Aß1-42). Forty Wistar rats were randomly divided into control, Aß1-42, SIF + Aß1-42, and SIF groups according to body weight. The rats in the SIF + Aß1-42 group and SIF group were intragastrically administered SIF suspension in 0.5% CMC-Na for 28 days, whereas the rats in control group and Aß1-42 group were administered the same volume of 0.5% CMC-Na. On day 14, the rats in the Aß1-42 group and SIF + Aß1-42 group were injected with Aß1-42 into the lateral cerebral ventricle with physiological saline. The rat brains were then sampled, and brain mitochondria were isolated. After this, the mitochondrial membrane potential (MMP) and mitochondrial redox state were measured. The contents of brain nuclear factor E2-related factor (Nrf2) and heme oxygenase-1 (HO-1) protein in brain tissue were quantitated by Western blot. The results showed that SIF maintained the MMP, elevated the reduced glutathione/oxidized glutathione (GSH/GSSG) ratio, and increased glutathione peroxidase (GPx) and manganese superoxide dismutase (MnSOD) protein expression in brain mitochondria. Additionally, SIF reversed the Aß1-42-induced downregulation of the protein expression of Nrf2 and HO-1 in brain tissue. These results indicated that SIF could alleviate the oxidative damage and maintain the redox imbalance in brain mitochondria damaged by Aß1-42. This might result from regulation of the Nrf2/HO-1 pathway.

The effects of phytosterol supplementation on serum LDL-C levels and learning ability in mice fed a high-fat, high-energy diet from gestation onward.

A high-fat, high-energy (HFE) diet may be deleterious to the cardiovascular system and mental health. We previously reported that serum cholesterol levels and escape latency were significantly increased in mice by feeding them an HFE diet from gestation onward. In this study, we examined whether an HFE diet supplemented with phytosterols fed to pregnant C57BL/6j dams and their offspring would protect the HFE-diet-induced compromise of the offspring's learning capability. We measured serum cholesterol levels, brain N-methyl-D-aspartate receptor (NMDAR1) mRNA and protein expression and liver sterol 27-hydroxylase (Cyp27a1) mRNA expression, as well as a Morris water maze performance. The results showed that, compared to mice consuming the HFE diet alone, those also consuming phytosterols (the HFE + PS diet) significantly decreased mean serum low-density lipoprotein cholesterol levels and altered brain NMDAR1 mRNA and protein expression and liver Cyp27a1 mRNA expression. The Morris water maze experiments indicated that dietary phytosterol supplementation slightly decreased the escape latency (p = 0.07). Collectively, these observations suggest that consumption of phytosterols from early in life may help alleviate the detrimental effects of HFE diets in mice.

The role of glutathione S-transferase M1 and T1 gene polymorphisms and fruit and vegetable consumption in antioxidant parameters in healthy subjects.

The correlation of glutathione S-transferase (GST) M1/T1 genetic polymorphisms with oxidative stress-related chronic diseases was proved recently. The aim of the present study was to investigate the association of GSTM1/T1 genetic polymorphisms with antioxidant biomarkers and consumption of fruits and vegetables (F&V) in healthy subjects. In this study, for conducting a 3 d dietary survey, 190 healthy adults were recruited. After DNA extraction, a multiple PCR method was used for GSTM1/T1 genotyping. A spectrophotometer method was applied for the determination of plasma total antioxidant capacity (T-AOC), vitamin C level and erythrocyte GST enzyme activity. A general linear model was used to compare the mean values of antioxidant parameters for different GSTM1/T1 genotypes and consumption of F&V. Polymorphisms of GSTM1/T1 had no effects on plasma T-AOC and vitamin C levels. Deletion of the GSTM1 gene decreased the erythrocyte GST activity. There was correlation between plasma T-AOC and consumption of F&V in the GSTM1⁻ or GSTT1⁺ subjects. A similar pattern was evident for erythrocyte GST activity in the GSTM1⁻ subjects. No association was found among consumption of F&V and GSTM1/T1 genotypes and plasma vitamin C level. Different consumption of F&V had no impact on plasma T-AOC and vitamin C levels in the GSTM1⁻/GSTT1⁺ or GSTM1⁻/GSTT1⁻ subjects. The erythrocyte GST activity was more sensitive to consumption of F&V in the individuals with the GSTM1⁻/GSTT1⁺ genotype. Association was found among GSTM1/T1 genotypes, antioxidant parameters and consumption of F&V. Large-scale and multiple ethnic studies are needed to further evaluate the relationship.

Genistein inhibits mitochondrial-targeted oxidative damage induced by beta-amyloid peptide 25-35 in PC12 cells.

The antioxidative properties of genistein (Gen) have been demonstrated by our previous studies and others, but its potential mechanism was not very clear. Because of the key role of mitochondria in oxidant production, we wondered if mitochondria were one of Gen's neuroprotective targets. In the present study we investigated whether Gen has protective effects on mitochondria damaged by Aß25-35. PC12 cells were pre-incubated with or without Gen for 2 h followed by the incubation with 20 µM Aß25-35 for another 24 h before mitochondrial membrane fluidity (MMF), mitochondrial membrane potential (MMP) , and mitochondrial redox state were measured. The results showed that Gen alleviated the decrease of MMF induced by Aß25-35, and maintained the MMP. Additionally, Gen promoted the mitochondrial antioxidative capability through increasing the GSH/GSSG ratio, GPx activity and MnSOD protein expression in mitochondria. Moreover, Gen reversed the changes of ChAT mRNA and AChE mRNA expression in cells induced by Aß25-35. These results suggested that Gen can protect the mitochondrial membrane and maintain redox state in mitochondria damaged by Aß25-35.

[Effects of genistein and folic acid on neuronal membrane and mitochondrial membrane damaged by ß-amyloid peptides 31-35].

OBJECTIVE: To observe the neuro-protective effects of genistein (Gen) and folic acid (FA) on neurons membrane and mitochondrial membrane damaged by ß-amyloid peptides 31-35 (Aß31-35). METHODS: The primary cultured rat cerebral cortical neurons were randomly divided into DMEM (control), Aß31-35 (25 µmol/L), Gen (Gen 27 µg/ml), FA (FA 40 µg/ml) and Gen + FA (Gen 27 µg/ml + FA 40 µg/ml). Gen and/or FA were added two hours before Aß31-35 addition. After twenty four hours, MTT assay was performed to measure the viability of cultured neurons. Fluorescence polarization was performed to observe the neuron cell membrane fluidity. The mitochondrial membrane potential (MMP) was determined to investigate the alteration of mitochondrial structure and function of neurons by laser scanning confocal microscope and a flow cytometer was used to investigate the activation of mitochondrial permeability transition pore (MPTP). Each experiment was repeated three times. RESULTS: Compared with group Aß31-35 (0.845 ± 0.050, F = 4.931, P < 0.05), the absorbance was significantly higher in group Gen (0.982 ± 0.110, t = 3.523, P < 0.01), FA (0.947 ± 0.061, t = 2.745, P < 0.01) and Gen + FA (0.996 ± 0.090, t = 3.966, P < 0.01). The viscosity of cell neuron membrane in group Gen (1.75 ± 0.28, t = 2.085, P < 0.05), FA (1.66 ± 0.37, t = 2.357, P < 0.05) and Gen + FA (1.50 ± 0.20, t = 3.784, P < 0.05) was significantly lower than that in group Aß31-35 (2.11 ± 0.44, F = 5.529, P < 0.01), which indicated the cell membrane fluidity was significantly higher in group Gen and/or FA than that in group Aß31-35. MMP was significantly decreased by Aß31-35 (3.364 ± 1.140, t = 3.949, P < 0.01) when comparing to control group (6.383 ± 1.683), while it was significantly increased by Gen (5.286 ± 1.792, t = 2.406, P < 0.05), FA (5.884 ± 2.022, t = 2.887, P < 0.01) and Gen + FA (6.120 ± 2.124, t = 3.304, P < 0.01) when comparing to group Aß31-35 (F = 7.585, P < 0.01). MPTP was activated by Aß31-35 and Gen and/or FA could reverse this progress. CONCLUSION: Gen and/or FA could protect the neuronal and mitochondrial membrane from the impairment induced by Aß31-35.

Neuroprotection of soyabean isoflavone co-administration with folic acid against beta-amyloid 1-40-induced neurotoxicity in rats.

Soya isoflavones (SIF) and folic acid (FA) both confer the biological properties of antioxidation; however, the mechanism of their antioxidant effect on nervous system development is unclear. Our purpose is to investigate the neuroprotective effects of SIF, FA or co-administration of SIF with FA against beta-amyloid 1-40 (Abeta1-40)-induced learning and memory impairment in rats. In the present study, the learning and memory ability of rats and the amount of amyloid-positive neurons in the cerebral cortex and hippocampal CA1 area were measured. The levels of total antioxidant capacity (T-AOC), glutathione (GSH) and glutathione peroxidase (GSH-Px) in serum and brain tissue were also measured. The results showed that intracerebroventricular administration of Abeta1-40 resulted in a dramatic prolongation of the escape latency; however, in the SIF, FA and SIF+FA treatment groups, the functional deficits of learning and memory were significantly improved. Moreover, after Abeta1-40 injection, the levels of T-AOC and GSH were profoundly decreased, suggesting a decline of antioxidant activity in the rats. However, intragastric pre-treatment with SIF, or FA, or SIF+FA resulted in a significant increase of antioxidative activity. SIF, or FA, or SIF+FA treatments also reversed the Abeta1-40-induced increase in the amount of amyloid-positive neurons. These results suggest that: (1) learning or memory impairment in experimental rats was caused by Abeta1-40, which is probably attributed to Abeta-induced oxidative damage and deposition of beta-amyloid peptides in the brain; (2) pre-administration of SIF and/or FA may prevent the pathological alterations caused by Abeta1-40 treatment and the neuroprotective effects of SIF and/or FA are indicated.

A peptide conjugate of vitamin E succinate targets breast cancer cells with high ErbB2 expression.

Overexpression of erbB2 is associated with resistance to apoptosis. We explored whether high level of erbB2 expression by cancer cells allows their targeting using an erbB2-binding peptide (LTVSPWY) attached to the proapoptotic alpha-tocopheryl succinate (alpha-TOS). Treating erbB2-low or erbB2-high cells with alpha-TOS induced similar levels of apoptosis, whereas alpha-TOS-LTVSPWY induced greater levels of apoptosis in erbB2-high cells. alpha-TOS rapidly accumulated in erbB2-high cells exposed to alpha-TOS-LTVSPWY. The extent of apoptosis induced in erbB2-high cells by alpha-TOS-LTVSPWY was suppressed by erbB2 RNA interference as well as by inhibition of either endocytotic or lysosomal function. alpha-TOS-LTVSPWY reduced erbB2-high breast carcinomas in FVB/N c-neu transgenic mice. We conclude that a conjugate of a peptide targeting alpha-TOS to erbB2-overexpressing cancer cells induces rapid apoptosis and efficiently suppresses erbB2-positive breast tumors.

Amphiregulin and ocular axial length.

PURPOSE: To assess the potential role of amphiregulin as messenger molecule in ocular axial elongation. METHODS: The experimental study included guinea pigs (total n = 78) (age: 3-4 weeks) which underwent bilateral lens-induced myopization and received 15 days later three intraocular injections in weekly intervals of amphiregulin antibody (doses:5 µg, 10 µg, 20 µg) into their right eyes, and three phosphate-buffered saline injections into their left eyes; and guinea pigs without lens-induced myopization and which received three unilateral intraocular injections of amphiregulin antibody (dose: 20 µg) or amphiregulin (doses: 1 ng; 10 ng; 20 ng) into their right eyes, and three phosphate-buffered saline injections into their left eyes. Seven days later, the animals were sacrificed. Intravitally, we performed biometry, and histology and immunohistochemistry post-mortem. RESULTS: In animals with bilateral lens-induced myopization, the right eyes receiving amphiregulin antibody showed reduced axial elongation in a dose-dependent manner (dose: 5 µg: side difference: 0.14 ± 0.05 mm;10 µg: 0.22 ± 0.06 mm; 20 µg: 0.32 ± 0.06 mm; p < 0.001), thicker sclera (all p < 0.05) and higher cell density in the retinal nuclear layers and retinal pigment epithelium (RPE) (all p < 0.05). In animals without lens-induced myopia, the right eyes with amphiregulin antibody application (20 µg) showed reduced axial elongation (p = 0.04), and the right eyes with amphiregulin injections experienced increased (p = 0.02) axial elongation in a dose-dependent manner (1 ng: 0.04 ± 0.06 mm; 10 ng: 0.10 ± 0.05 mm; 20 ng: 0.11 ± 0.06 mm). Eyes with lens-induced axial elongation as compared to eyes without lens-induced axial elongation revealed an increased visualization of amphiregulin upon immunohistochemistry and higher expression of mRNA of endogenous amphiregulin and epidermal growth factor receptor, in particular in the outer part of the retinal inner nuclear layer and in the RPE. CONCLUSION: Amphiregulin may be associated with axial elongation in young guinea pigs.

Elaidic acid induces cell apoptosis through induction of ROS accumulation and endoplasmic reticulum stress in SH­SY5Y cells.

Elaidic acid, which is a major trans fatty acid, has been reported to be involved in neurotoxicity; however, the underlying molecular mechanisms underlying its neurotoxic effects remain largely unknown. Therefore, the present study aimed to investigate the potential mechanisms underlying elaidic acid­induced neuronal damage in vitro. The SH­SY5Y neuroblastoma cell line was used as a model in the present study. Following treatment of cells with various concentrations of elaidic acid or with vehicle for 24 h, cell viability was measured using the MTT assay. Mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) release were measured using flow cytometry. Cell apoptosis was measured by Annexin V­fluorescein isothiocyanate/propidium iodide double staining, and cellular redox status was determined using ELISA analysis. Furthermore, western blotting was used to detect the protein expression levels of factors associated with oxidative damage and components of the endoplasmic reticulum (ER) stress/unfolded protein response (UPR) signaling pathways. The results demonstrated that elaidic acid treatment inhibited cell viability, elevated cell apoptosis and resulted in a loss of MMP. In addition, elaidic acid induced marked alterations in cellular redox status. Treatment with high doses of elaidic acid treatment also enhanced the release of ROS, and upregulated lipid peroxide and malondialdehyde levels; however, it reduced superoxide dismutase and glutathione peroxidase activities. Furthermore, elaidic acid resulted in upregulation of nuclear factor erythroid 2­related factor 2 and downregulation of heme oxygenase 1, which are two key antioxidative factors. Elaidic acid treatment also induced or inhibited the expression of numerous ER stress/UPR­associated molecules. It induced glucose­regulated protein 78 (GRP78) expression, whereas the expression levels of activating transcription factor 4 (ATF4) and CCAAT/enhancer­binding protein homologous protein (CHOP) were upregulated and then downregulated following treatment with various doses of elaidic acid. These results indicated that elaidic acid inhibited SH­SY5Y cell growth and induced apoptosis by enhancing oxidative stress and activating the ER stress/UPR signaling pathway and the GRP78/ATF4/CHOP pathway.

Neurocalcin-delta: a potential memory-related factor in hippocampus of obese rats induced by high-fat diet.

INTRODUCTION: Aberrant protein expression within the hippocampus has recently been implicated in the pathogenesis of obesity-induced memory impairment. OBJECTIVES: The objective of the current study was to search for specific memory-related factors in the hippocampus in obese rats. METHODS: Sprague-Dawley (SD) rats were fed either a high-fat (HF) diet or normal-fat (NF) diet for 10 weeks to obtain the control (CON), diet-induced obese rats (DIO) and diet-resistant (DR) rats. D-galactose was injected subcutaneously for 10 weeks to establish model (MOD) rats with learning and memory impairment. After the hippocampus of the rats sampling, the proteome analysis was conducted using two-dimensional get electrophoresis (2-DE) combined with peptide mass fingerprinting (PMF). RESULTS: We found 15 differential proteins that expressed in the hippocampus in rats induced by HF diet from the 2-DE map. In addition, Neurocalcin-delta (NCALD) was nearly down-regulated in the DR rats compared with CON rats and MOD rats, which was further confirmed by Western blot, real-time PCR and ELISA results. CONCLUSION: Our data demonstrates that the differential memory-related proteins were a reflection of the HF diet, but not potential factors in obesity proneness or obesity resistance. Furthermore, NCALD is proved to be a potential hippocampus-memory related factor related to obesity.

Inhibitory effects of apigenin on the growth of gastric carcinoma SGC-7901 cells.

AIM: To explore the growth inhibition and apoptosis-inducing effect of apigenin on human gastric carcinoma SGC-7901 cells. METHODS: The effects of apigenin on the growth, clone formation and proliferation of human gastric carcinoma SGC-7901 cells were observed by MTT, clone-forming assay, and morphological observation. Fluorescent staining and flow cytometry analysis were used to detect apoptosis of cells. RESULTS: Apigenin obviously inhibited the growth, clone formation and proliferation of SGC-7901 cells in a dose-dependent manner. Inhibition of growth was observed on d 1 at the concentration of 80 micromol/L, while after 4 d, the inhibition rate (IR) was 90%. The growth IRs at the concentration of 20, 40, and 80 micromol/L were 38%, 71%, and 99% respectively on the 7th d. After the cells were treated with apigenin for 48 h, the number of clone-forming in control, 20, 40, and 80 micromol/L groups was 217+/-16.9, 170+/-11.1 (P < 0.05), 98+/-11.1 (P < 0.05), and 25+/-3.5 (P < 0.05) respectively. Typical morphological changes of apoptosis was found by fluorescent staining. The cell nuclei had lost its smooth boundaries, chromatin was condensed, and cell nuclei were broken. Flow cytometry detected typical apoptosis peak. After the cells were treated with apigenin for 48 h, the apoptosis rates were 5.76%, 19.17%, and 29.30% respectively in 20, 40, and 80 micromol/L groups. CONCLUSION: Apigenin shows obvious inhibition on the growth and clone formation of SGC-7901 cells by inducing apoptosis.

Soy isoflavone alleviates Aß1-42-induced impairment of learning and memory ability through the regulation of RAGE/LRP-1 in neuronal and vascular tissue.

The neuroprotective properties of soy isoflavone (SIF) have been demonstrated by our previous studies and others, but its potential mechanism is not clear. Because of the key role of neurovascular dysfunction in the pathogenesis of Alzheimer's disease (AD), we hypothesized neurovascular tissue might be one neuroprotective target of SIF. In the present study, learning and memory ability, ß-amyloid (Aß) expressions both in neurovascular tissue and plasma, the receptor for advanced glycation end products (RAGE), low-density lipoprotein receptor-related protein (LRP)-1, nuclear factor-κB p65 (NF-κB p65), tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) expressions in neurovascular tissue were measured in Wistar rats following lateral cerebral ventricle administration of Aß1-42 by miniosmotic pump with or without intragastric administration of SIF from 14 days before surgery to the end of experiment. The results showed that SIF could improve the impairment of learning and memory of rats induced by Aß1-42, maintain Aß homeostasis in brain, regulate the disordered expressions of RAGE/LRP-1 and restrain RAGE related NF-κB and inflammatory cytokines activation in neurovascular structure. These results suggested that SIF could protect Aß-impaired learning and memory in rats, and its mechanism might be associated with the regulation of vascular Aß transportation and vascular inflammatory reaction.

Beta amyloid peptide (25-35) leading to inflammation through Toll-like receptors and the anti-inflammatory effect of genistein in BV-2 cells.

Genistein, the main soy isoflavone component, has received much attention for its potential multifunction. Here, we reported that in BV-2 cells, genistein significantly inhibited beta amyloid peptides 25-35 (Aß25-35)-induced inflammatory response. The results indicated that Aß25-35-stimulated BV-2 cells upregulated Toll-like receptors 2 and 4, Myd88, and IKK gene expression with the increasing expression of IL-6 and decreasing expression of TGF-ß and IL-10. Further, inhibiting TLR4 expression with small interfering RNA prevented the inflammatory response induced by Aß25-35, indicating the key role of TLRs in Aß-mediated inflammation. Genistein pre-treated BV-2 cells showed less inflammatory response when exposed to Aß25-35. These results suggested that Aß induced BV-2 cells inflammation though TLRs and genistein has an anti-inflammatory effect in vitro.

Flavonoids protect cerebrovascular endothelial cells through Nrf2 and PI3K from ß-amyloid peptide-induced oxidative damage.

ß-amyloid peptides (Aß) induced cerebrovascular dysfunction has been recognized as a vital factor involved in the pathogenesis of neurodegeneration. Genistein, a flavonoid, has antioxidative properties to prevent neurodegeneration induced by ß-amyloid peptides. In this study, we were investigating whether genistein could antagonize oxidative damage induced by ß-amyloid peptide 25-35 (Aß25-35) in bEND.3 cells, and also identifying the potential neuroprotective targets of genistein. Vitamin E was used as the positive control. The bEND.3 cells were pre-incubated with/out genistein or vitamin E for 2 h followed by the incubation with 25 µM A 25-35 for another 24 h. The reactive oxygen species (ROS), nitrotyrosine, cell redox state, mRNA or protein expressions of the factors on Nrf2 signaling pathway were measured after Aß25-35 treatment. The results showed that genistein alleviated the increase of ROS and nitrotyrosine production induced by Aß25-35, and maintained bEND.3 cell redox state by increasing GSH level and GSH/GSSG. Genistein could reverse the down-regulation of total protein and mRNA expression of NF-E2-related factor 2 (Nrf2), nuclear Nrf2, γ-glutamylcysteine synthetase (γ-GCS), phosphatidylinositol 3-kinase (PI3K) induced by Aß25-35; while PI3K inhibitor LY294002 could attenuate the activation effects of genistein on Nrf2, especially for the promotion of nuclear translocation. These results suggested that genistein could protect cerebrovascular endothelial cells from Aß25-35-induced oxidative damage. The potential mechanisms might be associated with the activation of Nrf2 signaling pathway by modulating PI3K activity.

Antagonizing effects of soybean isoflavones on ß-amyloid peptide-induced oxidative damage in neuron mitochondria of rats.

Soybean isoflavone (SIF) has been demonstrated to have neuroprotective effects induced by ß-amyloid peptides (Aß) through suppressing oxidative stress; however, the explicit mechanisms still remain uncovered. In the present study, 32 Wistar rats were randomly divided into four groups: an Aß1-42-treated group, a SIF + Aß1-42 group, a SIF-treated group and a control group. We measured the protein content of 8-hydroxydeoxyguanosine (8-OhdG) and mRNA expression of 8-oxoguanine DNA glycosylase (OGG1). The protein expression of OGG1, Bcl-xl, Bad, beta subunit of ATP synthase (ATPB) and pyruvate dehydrogenase (PDH) in brain was also measured. The results showed that the level of 8-OHdG in both SIF groups was significantly decreased compared to the Aß1-42-treated group (p < 0.05), while the mRNA and protein expression of OGG1 in the SIF + Aß1-42 groups were up-regulated compared with the Aß1-42-treated groups (p < 0.05). The expression of Bcl-xl was up-regulated in the SIF-treated group compared with the Aß1-42-treated groups (p < 0.05), while the expression of Bad was down-regulated in the two SIF-treated groups (p < 0.05). Aß1-42 significantly down-regulated the expression of ATPase and PDH proteins compared with the control group (p < 0.05). SIF reversed the down-regulation effects on the mitochondrial energy metabolic enzymes induced by Aß1-42 (p < 0.05) in the rats. These results suggest that SIF alleviate the oxidative stress in neurons and mitochondria of rat brains mediated by Aß1-42, and these protective effects might be associated with the regulation of OGG1, Bad, Bcl-xl, ATPB and PDH.