Effects and mechanisms of SNP-9 on Aβ25-35-induced damage in bEnd.3 cells / 中国药科大学学报

@#In order to investigate the effects of neuroprotective peptide SNP-9 which is derived from silk fibroin hydrolysate on the injury of the blood-brain barrier in Alzheimer′s disease (AD), Aβ25-35 was used to damage brain microvascular endothelial cells bEnd.3 to establish AD injury model and drug intervention was performed.MTT assay was used to detect the effects of SNP-9 and Aβ25-35 on cell viability.RT-qPCR was used to determine the effects of SNP-9 and Aβ25-35 on the mRNA levels of tight junctions (TJs)-related ZO-1, occludin and claudin-5.Western blot was used to detect the effects of SNP-9 and Aβ25-35 on the protein levels of TNF-α, phosphorylated NF-κB, NF-κB, IκBα and RAGE.The results showed that SNP-9 reduced bEnd.3 cell damage induced by Aβ25-35, and improved the abnormal mRNA levels of ZO-1, occludin and claudin-5 in model cells.It alleviated the abnormal protein levels of TNF-α, phosphorylated NF-κB, IκBα and RAGE induced by Aβ25-35. These results suggest that SNP-9 may regulate the levels of TNF-α in model cells by influencing RAGE/NF-κB pathway, and then ameliorate TJs-related abnormalities and alleviate bEnd.3 cell injury induced by Aβ25-35.

Noscapine inhibits migration of colon cancer SW480 cells by down-regulating Wnt3a/β-catenin signaling pathway and cadherin 17 / 中国肿瘤生物治疗杂志

@# Objective: To explore the effects of noscapine (Nos) on the expression of cadherin 17 (CDH17) in colon cancer SW480 cells and the mechanism of Nos on cell migration. Methods: SW480 cells were divided into the control group, empty vector (si-EV) group, CDH17 interference (si-CDH17) group, Nos treatment group, and CDH17 interference+Nos treatment (si-CDH17+Nos) group. Small interfering RNA (siRNA) was used to knockdown CDH17, and the selected concentration of Nos was (55.30±2.21) µg/ml (IC50). The mRNA expression of CDH17 was detected by qPCR; the apoptosis and migration abilities of SW480 cells were observed by Hoechst33258 staining and Transwell assay; the contents of VEGF, MMP2 and MMP9 in SW480 cells were measured by ELISA, and the protein expressions of CDH17, Wnt3a and β-catenin were determined by WB. Results: Compared with the control group, mRNA and protein expressions of CDH17 obviously decreased, cell apoptosis and migration significantly reduced, while the contents of VEGF, MMP2 and MMP9 as well as the protein expressions of Wnt3a and β-catenin significantly decreased in Nos treatment group, siCDH17 group and si-CDH17+Nos treatment group (all P<0.01).The effect of si-CDH17+Nos treatment was more significant than that of si-CDH17 (P<0.01). Conclusion: Nos induces apoptosis and inhibits the migration of human colon cancer SW480 cells, which may be related to the down-regulation of CDH17 expression and inhibition of the Wnt3a/β-catenin signaling pathway.

Role of Cerebrospinal Fluid Biomarkers in Clinical Trials for Alzheimer's Disease Modifying Therapies

Until now, a disease-modifying therapy (DMT) that has an ability to slow or arrest Alzheimer's disease (AD) progression has not been developed, and all clinical trials involving AD patients enrolled by clinical assessment alone also have not been successful. Given the growing consensus that the DMT is likely to require treatment initiation well before full-blown dementia emerges, the early detection of AD will provide opportunities to successfully identify new drugs that slow the course of AD pathology. Recent advances in early detection of AD and prediction of progression of the disease using various biomarkers, including cerebrospinal fluid (CSF) Abeta1-42, total tau and p-tau181 levels, and imagining biomarkers, are now being actively integrated into the designs of AD clinical trials. In terms of therapeutic mechanisms, monitoring these markers may be helpful for go/no-go decision making as well as surrogate markers for disease severity or progression. Furthermore, CSF biomarkers can be used as a tool to enrich patients for clinical trials with prospect of increasing statistical power and reducing costs in drug development. However, the standardization of technical aspects of analysis of these biomarkers is an essential prerequisite to the clinical uses. To accomplish this, global efforts are underway to standardize CSF biomarker measurements and a quality control program supported by the Alzheimer's Association. The current review summarizes therapeutic targets of developing drugs in AD pathophysiology, and provides the most recent advances in the

HIV-1 Tat Protein Promotes Amyloid beta Generation and Tau Phosphorylation in Rat Hippocampal Slices

HIV-1 Tat protein has been implicated as a causative agent in the pathogenesis of HIV-1-associated neurocognitive disorder (HAND) and Alzheimer's disease (AD)-like pathology in HIV-1 infected patients. Here, we provide insights into the potential roles of extracellular HIV-1 Tat protein in amyloid beta (Abeta) generation and Tau phosphorylation, two major neuropathological features of AD. Exposure of the rat hippocampal slices to the full-length HIV-1 Tat protein (Tat1-86) for 3 days led to the increased levels of Abeta precursor protein (APP) accumulation, which accompanied by Abeta generation in the hippocampus, the brain region most commonly damaged in HIV-1-associated dementia (HAD). Moreover, extracellular HIV-1 Tat significantly stimulated the level of phosphrylated Tau (pTau) identified using immunoblotting with AT8 antibody, which recognizes abnormally hyperphosphorylated Tau. Collectively, our data suggest that HIV-1 Tat plays important roles in increasing the levels of APP accumulation, Abeta generation and Tau phosphorylation in the hippocampus, and thereby might contribute to the development of AD-like pathology in HIV-1-infected patients.

Precautionary effects of Red Liriope platyphylla on NGF secretion and Abeta42 deposition under the preclinical stage of Alzheimer's disease in Tg2576 mice / 한국실험동물학회지

Red Liriope platyphylla (RLP) has been manufactured from Liriope platyphylla (L. platyphylla, LP) roots using steaming process and investigated as a curative agent for treatment of diabetes, obesity and neurodegenerative disorders. To examine the precautionary effects of aqueous extract RLP (AEtRLP) on the preclinical stages of Alzheimer's Disease (AD), alterations of the key factors influencing AD were investigated in Tg2576 mice after AEtRLP7 treatment for 4 months. Abeta-42 peptides level was significantly decreased in the brain of AEtRLP7-treated Tg2576 mice compared to vehicle-treated Tg2576 mice, although significant differences on improving behavioral defects were not observed in the same group. The concentration of nerve growth factor (NGF) in serum was also higher in AEtRLP7-treated Tg2576 mice than vehicle-treated Tg2576 mice. However, the phosphorylation of TrkA and Erk among the downstream effectors of the high affinity NGF receptor was significantly lower in AEtRLP7-treated Tg2576 mice. A similar pattern was observed in the expression level of downstream effectors within low affinity NGF receptor. Overall, these results suggest that AEtRLP7 can contribute to preventing the production and deposition of Abeta-42 peptides during the early progression stage of AD in the brain of Tg2576 mice through increased NGF secretion.

Zinc-Triggered Induction of Tissue Plasminogen Activator and Plasminogen in Endothelial Cells and Pericytes

Cerebral amyloid angiopathy (CAA) is common in patients with Alzheimer's disease (AD) and may contribute to cerebral hemorrhage. We previously demonstrated that tissue plasminogen activator (tPA) and plasminogen (PLG) accumulated at the periphery of compact amyloid-cored plaques and in the walls of CAA-containing blood vessels in the brains of Tg2576 mice, a widely used AD mouse model. We had also observed that zinc-triggered tPA and PLG induction were observed in mouse cortical cultures. Because zinc also accumulates in amyloid plaques and blood vessel walls in AD brains, we examined whether zinc increases mRNA and protein levels of tPA and PLG in brain endothelial cells and pericytes. Four hours after the exposure of brain endothelial cells (bEnd.3) to 40 microM zinc, the mRNA and protein expressions of tPA and its substrate PLG were significantly increased. In the case of brain pericyte cultures, increases in tPA and PLG expression were also detected 2 hr after treatment. However, amyloid-beta (Abeta)1-42 oligomers did not augment tPA and PLG expression in bEnd.3 cells and pericytes, suggesting that zinc but not Abeta induces tPA and PLG accumulation in CAA found in the AD brain.

Effects of Red Liriope platyphylla on NGF secretion ability, NGF receptor signaling pathway and gamma-secretase components in NSE/hAPPsw transgenic mice expressing Alzheimer's Disease / 한국실험동물학회지

Liriope platyphylla (LP) has long been regarded as a curative herb for the treatment of diabetes, asthma, and neurodegenerative disorders. To examine the therapeutic effects of Red LP (RLP) manufactured by steaming process on neurodegenerative disorders, significant alteration of the key factors influencing Alzheimer's Disease (AD) was detected in NSE/hAPPsw transgenic (Tg) mice after RLP treatment. The concentration of nerve growth factor (NGF) in serum increased in RLP-treated NSE/hAPPsw Tg mice compared with vehicle-treated Tg mice. However, downstream effectors of the NGF receptor signaling pathway, including TrkA and p75NTR proteins, were suppressed in RLP-treated NSE/hAPPsw Tg mice. Especially, Tg mice showed decreased levels of TrkA, p75NTR, and RhoA expression. Production of Abeta-42 peptides was lower in RLP-treated NSE/hAPPsw Tg mice than in vehicle-treated Tg mice. Further, analysis of gamma-secretase components showed that Abeta-42 peptide expression was downregulated. Of the four components, the expression of APH-1 and Nicastrin (NCT) decreased in RLP-treated NSE/hAPPsw Tg mice, whereas expression of PS-2 and Pen-2 was maintained or increased within the same group. Overall, these results suggest that RLP can help relieve neurodegenerative diseases, especially AD, through upregulation of NGF secretion ability, activation of NGF signaling pathway, downregulation of Abeta-42 peptide deposition, and alteration of gamma-secretase components.

Peroxiredoxin I regulates the component expression of gamma-secretase complex causing the Alzheimer's disease / 한국실험동물학회지

Peroxiredoxin I (Prx I) is a member of the peroxiredoxins (Prxs) family, which are antioxidant enzymes that regulate various cellular process via intracellular oxidative signal pathways. In order to investigate the correlation between Prx I and the gamma-secretase complex, which causes Alzheimer's disease (AD), the expression level of Prx I was firstly evaluated in an animal model for AD. NSE/hPen-2 transgenic (Tg) mice, which were used as animal model in this study, showed a high level of Pen-2 expression and accumulation of Abeta-42 peptides in the hippocampus of brain. The expression level of Prx I was significantly higher on the mRNA and protein level in the brain of this model, while not change in Prx VI expression was observed. Furthermore, to verify the effect of Prx I on the gamma-secretase components in vitro, the expression level of these components was analyzed in the Prx I transfectants. Of the components of the gamma-secretase complex, the expression of PS-2 and Pen-2 was lower in the transfectants overexpressing Prx I compared to the vector transfectants. However, the expression of APP, NCT and APH-1 did not change in Prx I transfectants. Therefore, these results suggested that the expression of Prx I may be induced by the accumulation of Abeta-42 peptides and the overexpression of Prx I in neuroblastoma cells may regulate the expression of gamma-secretase components.

Drug Development for Alzheimer's Disease: Recent Progress

Alzheimer's disease, the most common cause of dementia, is characterized by two major pathological hallmarks: amyloid plaques and neurofibrillary tangles. Based on these two indicators, an amyloid cascade hypothesis was proposed, and accordingly, most current therapeutic approaches are now focused on the removal of beta-amyloid peptides (Abeta from the brain. Additionally, strategies for blocking tau hyperphosphorylation and aggregation have been suggested, including the development of drugs that can block the formation of tangles. However, there are no true disease-modifying drugs in the current market, though many drugs based on theories other than Abeta and tau pathology are under development. The purpose of this review was to provide information on the current development of AD drugs and to discuss the issues related to drug development.

Protective Effect of HSP90 on Neuronal Cell Death-induced by beta-Amyloid Peptide / 체질인류학회지

In the present study, we determined the protective mechanism of HSP90 against neuronal cell death induced by Abeta. For the evaluation of protective role of HSP90, we used human neuroblastoma SK-N-SH cell lines, examined AlamarBlue assay, Western blot analysis and immunofluorescence assay. Incubation of SK-N-SH cells with Abeta significantly induced neuronal cell death. However, HSP90 induced by mild heat shock could attenuate neuronal apoptosis in Abeta treated condition. To identify the role of HSP90, we determined localization of HSP90 in SK-N-SH cells. Interestingly, HSP90 was increased and localized in mitochondria as treatment of mild heat shock. Also, treatment or increase of HSP90 largely elevated level of Bcl-2 expression, whereas inhibition of HSP90 with HSP90 antisense oligonucleotide significantly decreased Bcl-2 expression. In contrast to Bcl-2, Bax expression was regulated independently by HSP90. Moreover, increase of HSP90 could attenuate collapse of mitochondrial membrane potential induced by Abeta. However, HSP90 antisense oligonucleotide largely increase breakdown of mitochondrial membrane potential induced by Abeta. These data suggest that HSP90 as chaperone protein significantly attenuates neuronal damage and protects neuroanl cells from neurotoxin such as Abeta.

Protein Kinase C-mediated Neuroprotective Action of (-)-epigallocatechin-3-gallate against Abeta1-42-induced Apoptotic Cell Death in SH-SY5Y Neuroblastoma Cells

The neurotoxicity of amyloid beta (Abeta) is associated with an increased production of reactive oxygen species and apoptosis, and it has been implicated in the development of Alzheimer's disease. While (-)-epigallocatechin-3-gallate (EGCG) suppresses Abeta-induced apoptosis, the mechanisms underlying this process have yet to be completely clarified. This study was designed to investigate whether EGCG plays a neuroprotective role by activating cell survival system such as protein kinase C (PKC), extracellular-signal-related kinase (ERK), c-Jun N-terminal kinase (JNK), and anti-apoptotic and pro-apoptotic genes in SH-SY5Y human neuroblastoma cells. One microM Abeta1-42 decreased cell viability, which was correlated with increased DNA fragmentation evidenced by DAPI staining. Pre-treatment of SH-SY5Y neuroblastoma cells with EGCG (1microM) significantly attenuated Abeta1-42-induced cytotoxicity. Potential cell signaling candidates involved in this neuroprotective effects were further examined. EGCG restored the reduced PKC, ERK, and JNK activities caused by Abeta1-42 toxicity. In addition, gene expression analysis revealed that EGCG prevented both the Abeta1-42-induced expression of a pro-apoptotic gene mRNA, Bad and Bax, and the decrease of an anti-apoptotic gene mRNA, Bcl-2 and Bcl-xl. These results suggest that the neuroprotective mechanism of EGCG against Abeta1-42-induced apoptotic cell death includes stimulation of PKC, ERK, and JNK, and modulation of cell survival and death genes.

Protective Effect of Green Tea Extract on Neuronal Cell Death in Alzheimer Model using beta-amyloid Peptide / 대한해부학회지

In the present study, we determined whether green tea extract, EGCG protected against beta-amyloid induced neurotoxicity and learning impairment in vitro and in vivo models. Incubation of SK-N-SH cells with Abeta induced activation of caspase-3, mitochondrial dysfunction such as collapse of mitochondrial membrane potential (MMP) and release of cytosolic cytochrome c. Interestingly, pre-treatment of EGCG reduced significantly activation of caspase-3 and increase of mitochondrial damage such as the breakdown of MMP and release of cytochrome c, eventually attenuated the cell death induced by Abeta. These results show that EGCG inhibited caspase activity and blocked mitochondrial damage. For in vivo experiment, ICR mice received vehicle or vehicle plus EGCG (10 mg/kg) i.p. for 3 days. Before 2 days of treatment, 5 microliter of PBS containing 8 nmol of Abeta1-42 were injected into the lateral ventricle. On the 14th day of treatment, animals were applied to passive avoidance test, and after behavial test, animals were sacrificed. Then, morphological techniques were used to determine the extent of neuronal degeneration in the hippocampus. Abeta, but not PBS, injections into hippocampus led to neuronal loss and evidence of widespread apoptosis. EGCG treated animals had significant reductions in the amount of neuronal degeneration, and TUNEL positive cells compared with Abeta alone treated animals. These data suggest that EGCG at therapeutically relevant concentrations, might protect against neuronal degeneration induced by Abeta.

Usefulness of Anti-beta2-Glycoprotein I Antibody Test for the Diagnosis of Antiphospholipid Syndrome / 대한임상병리학회지

BACKGROUND: The conventional anticardiolipin antibody (aCL)-ELISA test that has been widely used to diagnose antiphospholipid syndrome (APS) has drawbacks in that false-positive reactions can occur. There have been considerable controversy as to the exact nature of the epitopes to which antiphosholipid antibodies (a PL) are directed. Almost all investigators now agree that the actual antigen to which aPL derived from patient with APS is directed, is beta2-glycoprotein I (beta2GPI). Therefore, we thought that anti-beta2GPI antibodies (abeta2GPI) might be a more specific marker for APS, and attempted to evaluate the usefulness of abeta2GPI test. METHODS: ELISA tests for a CL-IgG and abeta2GPI-IgG were performed simultaneously using the sera from 70 patients with clinically suspected APS and 10 healthy volunteers. The results of abeta2GPI were compared with those of aCL and evaluated clinically by reviewing the medical records. RESULTS: The correlation coefficient between the two was 0.54 (p<0.005). Twelve of 70 patients were abeta2GPI-positive and they were also positive for aCL (mean 45GPL). Forty of 58 abeta2GPI- negative patients were aCL-positive, and many of them were diagnosed to have APS clinically. There was no case showing aCL-negative but abeta2GPI-positive result. CONCLUSIONS: According to our results, abeta2GPI test seems specific but too insensitive to differentiate APS by itself, so it has no additional diagnostic value superior to aCL test. We believe that a study which includes more cases and various test methods will be needed for the precise assessment of abeta2GPI test.