APPswe Transgenic Mice Research Articles

Aβ‐potentiated and Aβ‐independent age‐related opacity changes in the lens of the eye in wild‐type and APPswe transgenic mice

AbstractBackgroundThe lens of the eye is composed of crystallin proteins. These proteins have been shown to interact with Aβ in particular in Alzheimer’s disease. Crystallin proteins undergo various post‐translational modifications during aging that disrupt the normal functioning of these proteins resulting in protein aggregation and light scattering. We expand on our previous work and investigated here the aging effect on lens opacity in an Aβ‐independent (wild‐type mice) and Aβ‐potentiated (Alzheimer’s disease transgenic mice [APPswe]) environment.MethodMice were bred, maintained and genotyped at Boston University. Mice were sacrificed at ages 8‐35 months, perfused with phosphate buffer saline, lenses were isolated and imaged under two different sources of light using a D70 digital Nikon camera and a Zeiss stereophotomicroscope.ResultWild‐type aged mice demonstrated light scattering and opacities in two distinct regions of the lens in aged mice compared to younger mice. Moreover, APPswe aged mice showed increased scattering in the outer layer compared to wild‐type aged mice.ConclusionTwo distinct light scattering regions of the lens are affected during aging involving Aβ‐potentiated mechanisms in APPswe mice and Aβ‐independent mechanisms in wild‐type mice.

Adenovirus 36 improves glycemic control and markers of Alzheimer's disease pathogenesis

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder worldwide. While the causes of AD are unclear, several risk factors have been identified, including impaired glycemic control, which significantly increases the risk of cognitive decline and AD. In vitro and in vivo studies show that human adenovirus 36 (Ad36) improves glycemic control by increasing cellular glucose uptake in cells, experimental animal models and in humans who are naturally exposed to the virus. This study, tested improvement in glycemic control by Ad36 and delay in onset of cognitive decline in APPswe transgenic mice (Tg2576 line), a model of genetic predisposition to impaired glycemic control and AD. Three-month old APPswe mice were divided into Ad36 infected (Ad36) or mock infected (control) groups and baseline glycemic control measured by glucose tolerance test (GTT) prior to infection. Changes in glycemic control were determined 10- and 24-week post infection. Serum insulin was also measured during GTT. Cognition was determined by Y-maze test, while motor coordination and skill acquisition by rotarod test. Glycemic control as determined by GTT showed less deterioration in Ad36 infected mice over time, accompanied by a significant attenuation of cognitive decline. Analysis of brain tissue lysate showed significantly reduced levels of amyloid beta 42 in Ad36 mice relative to control mice. Golgi-Cox staining analysis also revealed reduced dendritic spines and synaptic gene expression in control mice compared to Ad36 infected mice. This proof of concept study shows that in a mouse model of AD, Ad36 improves glycemic control and ameliorates cognitive decline.

Curcumin restores innate immune Alzheimer's disease risk gene expression to ameliorate Alzheimer pathogenesis.

Alzheimer's disease (AD) genetics implies a causal role for innate immune genes, TREM2 and CD33, products that oppose each other in the downstream Syk tyrosine kinase pathway, activating microglial phagocytosis of amyloid (Aβ). We report effects of low (Curc-lo) and high (Curc-hi) doses of curcumin on neuroinflammation in APPsw transgenic mice. Results showed that Curc-lo decreased CD33 and increased TREM2 expression (predicted to decrease AD risk) and also increased TyroBP, which controls a neuroinflammatory gene network implicated in AD as well as phagocytosis markers CD68 and Arg1. Curc-lo coordinately restored tightly correlated relationships between these genes' expression levels, and decreased expression of genes characteristic of toxic pro-inflammatory M1 microglia (CD11b, iNOS, COX-2, IL1β). In contrast, very high dose curcumin did not show these effects, failed to clear amyloid plaques, and dysregulated gene expression relationships. Curc-lo stimulated microglial migration to and phagocytosis of amyloid plaques both in vivo and in ex vivo assays of sections of human AD brain and of mouse brain. Curcumin also reduced levels of miR-155, a micro-RNA reported to drive a neurodegenerative microglial phenotype. In conditions without amyloid (human microglial cells in vitro, aged wild-type mice), Curc-lo similarly decreased CD33 and increased TREM2. Like curcumin, anti-Aβ antibody (also reported to engage the Syk pathway, increase CD68, and decrease amyloid burden in human and mouse brain) increased TREM2 in APPsw mice and decreased amyloid in human AD sections ex vivo. We conclude that curcumin is an immunomodulatory treatment capable of emulating anti-Aβ vaccine in stimulating phagocytic clearance of amyloid by reducing CD33 and increasing TREM2 and TyroBP, while restoring neuroinflammatory networks implicated in neurodegenerative diseases.

Crocetin attenuates inflammation and amyloid-\u03b2 accumulation in APPsw transgenic mice

BackgroundCrocetin, an agent derived from saffron, has multiple pharmacological properties, such as neuroprotective, anti-oxidant, and anti-inflammatory actions. These properties might benefit the treatment of Alzheimer’s disease (AD). In the present study, we tested whether crocetin attenuates inflammation and amyloid-β (Aβ) accumulation in APPsw transgenic mice, AD mouse models. Cell viability and the levels of Aβ40 and Aβ42 in HeLa cells stably transfected with Swedish mutant APP751 were evaluated. Mice with Swedish mutant APP751 transgene were used as transgenic mouse models of AD, and were orally administrated with crocetin. Aβ protein and inflammatory cytokines were measured with ELISA. NF-κB and P53 were measured with western blot assay. Learning and memory were analyzed with Morris water maze and novel object recognition tests.ResultsCrocetin significantly reduced Aβ40 and Aβ42 secretion in Hela cells without effecting cell viability. In AD transgenic mice, crocetin significantly reduced the pro-inflammatory cytokines and enhanced anti-inflammatory cytokine in plasma, suppressed NF-κB activation and P53 expression in the hippocampus, decreased Aβ in various brain areas, and improved learning and memory deficits.ConclusionCrocetin improves Aβ accumulation-induced learning and memory deficit in AD transgenic mice, probably due to its anti-inflammatory and anti-apoptotic functions.

CRISPR/Cas9 Mediated Disruption of the Swedish APP Allele as a Therapeutic Approach for Early-Onset Alzheimer’s Disease

The APPswe (Swedish) mutation in the amyloid precursor protein (APP) gene causes dominantly inherited Alzheimer’s disease (AD) as a result of increased β-secretase cleavage of the amyloid-β (Aβ) precursor protein. This leads to abnormally high Aβ levels, not only in brain but also in peripheral tissues of mutation carriers. Here, we selectively disrupted the human mutant APPSW allele using CRISPR. By applying CRISPR/Cas9 from Streptococcus pyogenes, we generated allele-specific deletions of either APPSW or APPWT. As measured by ELISA, conditioned media of targeted patient-derived fibroblasts displayed an approximate 60% reduction in secreted Aβ. Next, coding sequences for the APPSW-specific guide RNA (gRNA) and Cas9 were packaged into separate adeno-associated viral (AAV) vectors. Site-specific indel formation was achieved both in primary neurons isolated from APPSW transgenic mouse embryos (Tg2576) and after co-injection of these vectors into hippocampus of adult mice. Taken together, we here present proof-of-concept data that CRISPR/Cas9 can selectively disrupt the APPSW allele both ex vivo and in vivo—and thereby decrease pathogenic Aβ. Hence, this system may have the potential to be developed as a tool for gene therapy against AD caused by APPswe and other point mutations associated with increased Aβ.

지구성 운동이 알츠하이머 질환모델 동물의 저하된 뇌 인슐린 반응에 미치는 영향

This study shows the effect of long-term treadmill exercise on the expression level of amyloid beta protein and C-terminal peptide fragment of amyloid precursor protein (APP-C99), cognitive function and diabetes which has been known that highly related to Alzheimer’s disease.BR Comparing to Alzheimer’s disease animal model group, the group performed treadmill exercise for 16 weeks has shown the decrease of Aβ and APP-C99 expression and the increase of Aβ-induced intracellular downstream proteins including Akt, p-Akt, p85, p-p85, but There was no difference between groups GSK3β and p-GSK3β. Also, it demonstrated that treadmill exercise ameliorates decreased insulin response and insulin-related proteins, such as IR, p-IR, IDE, and GLUT-1 and increases the blood glucose level.BR Searching for the effects of exercising on the cognition of APPsw transgenic mouse model, water maze test was performed and the exercise group showed improvement of cognition. It could be considered that long-term treadmill exercise reduces the accumulation of amyloid beta protein through activating the intracellular signal of insulin. Furthermore, cognitive function was enhanced.BR Therefore, long-term exercise prevents the cause of Alzheimer’s disease and alleviates the symptoms.

Retro-inverso peptide inhibitor nanoparticles as potent inhibitors of aggregation of the Alzheimer's Aβ peptide

Aggregation of amyloid-β peptide (Aβ) is a key event in the pathogenesis of Alzheimer's disease (AD). We investigated the effects of nanoliposomes decorated with the retro-inverso peptide RI-OR2-TAT (Ac-rGffvlkGrrrrqrrkkrGy-NH2) on the aggregation and toxicity of Aβ. Remarkably low concentrations of these peptide inhibitor nanoparticles (PINPs) were required to inhibit the formation of Aβ oligomers and fibrils in vitro, with 50% inhibition occurring at a molar ratio of ~1:2000 of liposome-bound RI-OR2-TAT to Aβ. PINPs also bound to Aβ with high affinity (Kd=13.2-50 nM), rescued SHSY-5Y cells from the toxic effect of pre-aggregated Aβ, crossed an in vitro blood–brain barrier model (hCMEC/D3 cell monolayer), entered the brains of C57 BL/6 mice, and protected against memory loss in APPSWE transgenic mice in a novel object recognition test. As the most potent aggregation inhibitor that we have tested so far, we propose to develop PINPs as a potential disease-modifying treatment for AD.

COMPARATIVE ANALYSIS OF F-18 FDG AND COPPER-64 UPTAKE IN THE BRAINS OF APPSWE TRANSGENIC MICE FOR EARLY DIAGNOSIS OF ALZHEIMER'S DISEASES USING 64CUCL2-PET/CT

COMPARATIVE ANALYSIS OF F-18 FDG AND COPPER-64 UPTAKE IN THE BRAINS OF APPSWE TRANSGENIC MICE FOR EARLY DIAGNOSIS OF ALZHEIMER'S DISEASES USING 64CUCL2-PET/CT

NDP-α-MSH induces intense neurogenesis and cognitive recovery in Alzheimer transgenic mice through activation of melanocortin MC4 receptors.

Melanocortins exert neuroprotection in a variety of experimental neurodegenerative disorders, including Alzheimer's disease (AD). Further, in previous research we showed that these endogenous peptides stimulate neurogenesis in an acute neurodegenerative disorder such as ischemic stroke. In the present research, we investigated the potential neurogenic effect of melanocortins in AD using APPSwe transgenic mice (Tg2576). To this purpose, 24week-old animals were prepared for 5-bromo-2'-deoxyuridine (BrdU) labeling of proliferating cells on days 1-11 of the study. Treatment of Tg2576 mice with nanomolar doses of the melanocortin analog [Nle(4),D-Phe(7)]α-melanocyte-stimulating hormone (NDP-α-MSH), administered once daily from day 1 to 50, improved brain histology and cognitive functions relative to saline-treated Tg2576 animals. No signs of toxicity were observed. Immunohistochemical examination of the hippocampus at the end of the study (day 50) showed that NDP-α-MSH-treated Tg2576 mice had a greater number of BrdU immunoreactive cells colocalized with NeuN (an indicator of mature neurons) and Zif268 (an indicator of functionally integrated neurons) in the dentate gyrus, relative to saline-treated Tg2576 animals; no newly formed astrocytes were found. Animal pretreatment with the selective melanocortin MC4 receptor antagonist HS024 before each NDP-α-MSH administration prevented all the beneficial effects of the peptide. The present data indicate that MC4 receptor stimulation by a melanocortin prevents cognitive decline in experimental AD, this effect being associated not only with neuroprotection but also with an intense neurogenesis. MC4 receptor agonists could be innovative and safe candidates to counteract AD progression in humans.

Revisiting the peripheral sink hypothesis: inhibiting BACE1 activity in the periphery does not alter β-amyloid levels in the CNS.

Aggregation of amyloid beta (Aβ) peptides and the subsequent neural plaque formation is a central aspect of Alzheimer's disease. Various strategies to reduce Aβ load in the brain are therefore intensely pursued. It has been hypothesized that reducing Aβ peptides in the periphery, that is in organs outside the brain, would be a way to diminish Aβ levels and plaque load in the brain. In this report, we put this peripheral sink hypothesis to test by investigating how selective inhibition of Aβ production in the periphery using a β-secretase (BACE)1 inhibitor or reduced BACE1 gene dosage affects Aβ load in the brain. Selective inhibition of peripheral BACE1 activity in wild-type mice or mice over-expressing amyloid precursor protein (APPswe transgenic mice; Tg2576) reduced Aβ levels in the periphery but not in the brain, not even after chronic treatment over several months. In contrast, a BACE1 inhibitor with improved brain disposition reduced Aβ levels in both brain and periphery already after acute dosing. Mice heterozygous for BACE1, displayed a 62% reduction in plasma Aβ40, whereas brain Aβ40 was only lowered by 11%. These data suggest that reduction of Aβ in the periphery is not sufficient to reduce brain Aβ levels and that BACE1 is not the rate-limiting enzyme for Aβ processing in the brain. This provides evidence against the peripheral sink hypothesis and suggests that a decrease in Aβ via BACE1 inhibition would need to be carried out in the brain. Aggregation of amyloid beta (Aβ) peptides in the brain is a central aspect of Alzheimer's disease. In this study, we demonstrate that inhibition of Aβ formation by BACE1 inhibitors needs to be carried out in the brain and that reduction of Aβ in the periphery is not sufficient to reduce brain Aβ levels. This information is useful for developing future Aβ-targeting therapies for Alzheimer's disease.

Melanocortins protect against brain damage and counteract cognitive decline in a transgenic mouse model of moderate Alzheimer׳s disease

We previously reported that melanocortins induce neuroprotection in experimental acute and chronic neurodegenerative conditions, including Alzheimer׳s disease (AD) of mild severity. Here we investigated whether melanocortins afford neuroprotection and counteract cognitive decline in AD with a medium level of severity by using 24 week-old (at the start of the study) APPSwe transgenic mice (Tg2576). Saline-treated (days 1–50) control Tg2576 mice showed an impairment in spatial learning and memory, associated (at day 50, end of the study) with hippocampus at low levels of the synaptic activity-dependent gene Zif268, relevant brain changes such as cerebral cortex/hippocampus increased level of β-amyloid (Aβ) deposit, and neuronal loss, in comparison with wild-type animals. Treatment of Tg2576 mice (once daily at days 1–50) with a nanomolar dose of the melanocortin analog [Nle4,D-Phe7]α-melanocyte-stimulating hormone (NDP-α-MSH) reduced cerebral cortex/hippocampus level of Aβ deposit, decreased neuronal loss, increased hippocampus Zif268 expression and improved cognitive functions, relative to saline-treated Tg2576 mice. Pharmacological blockade of melanocortin MC4 receptors with the MC4 receptor antagonist HS024 prevented all favorable effects of NDP-α-MSH. Our data indicate that MC4 receptor-stimulating melanocortins are able to counteract cognitive decline in experimental AD of medium severity through induction of neuroprotection and improvement of synaptic transmission. After further studies, these agents could gain a role as disease modifying therapeutics for AD.

Astrocytosis precedes amyloid deposition in Alzheimer's Tg2576 APPswe transgenic mice: A multi-tracer microPET imaging study

Astrocytosis precedes amyloid deposition in Alzheimer's Tg2576 APPswe transgenic mice: A multi-tracer microPET imaging study

Neurotrophic and Neuroprotective Actions of (−)- and (+)-Phenserine, Candidate Drugs for Alzheimer’s Disease

Neuronal dysfunction and demise together with a reduction in neurogenesis are cardinal features of Alzheimer’s disease (AD) induced by a combination of oxidative stress, toxic amyloid-β peptide (Aβ) and a loss of trophic factor support. Amelioration of these was assessed with the Aβ lowering AD experimental drugs (+)-phenserine and (−)-phenserine in neuronal cultures, and actions in mice were evaluated with (+)-phenserine. Both experimental drugs together with the metabolite N1-norphenserine induced neurotrophic actions in human SH-SY5Y cells that were mediated by the protein kinase C (PKC) and extracellular signal–regulated kinases (ERK) pathways, were evident in cells expressing amyloid precursor protein Swedish mutation (APPSWE), and retained in the presence of Aβ and oxidative stress challenge. (+)-Phenserine, together with its (−) enantiomer as well as its N1- and N8-norphenserine and N1,N8-bisnorphenserine metabolites, likewise provided neuroprotective activity against oxidative stress and glutamate toxicity via the PKC and ERK pathways. These neurotrophic and neuroprotective actions were evident in primary cultures of subventricular zone (SVZ) neural progenitor cells, whose neurosphere size and survival were augmented by (+)-phenserine. Translation of these effects in vivo was assessed in wild type and AD APPswe transgenic (Tg2576) mice by doublecortin (DCX) immunohistochemical analysis of neurogenesis in the SVZ, which was significantly elevated by 16 day systemic (+)-phenserine treatment, in the presence of a (+)-phenserine-induced elevation in brain- derived neurotrophic factor (BDNF).

Longitudinal Characterization of the Brain Proteomes for the Tg2576 Amyloid Mouse Model Using Shotgun Based Mass Spectrometry

Neurodegenerative disorders are often defined pathologically by the presence of protein aggregates, such as amyloid plaques composed of β-amyloid (Aβ) peptide in Alzheimer's disease. Such aggregates are the result of abnormal protein accumulation and may lead to neuronal dysfunction and cell death. In this study, APPSWE transgenic mice (Tg2576), which overexpress the Swedish mutated form of human amyloid precursor protein (APP), were used to study the brain proteome associated with amyloid plaque deposition. The major aim of the study was to map and compare the Tg2576 model brain proteome profiles during pathology progression using a shotgun approach based on label free quantification with mass spectrometry. Overall, 1085 proteins were identified and longitudinally quantified. Principal component analysis (PCA) showed the appearance of the pathology onset between twelve and fifteen months, correlating with sharp amyloid plaque accumulation within the same ages. Cluster analysis followed by protein-protein interaction analysis revealed an age-dependent decrease in mitochondrial protein expression. We identified 57 significantly affected mitochondrial proteins, several of which have been reported to alter expression in neurological diseases. We also found ten proteins that are upregulated early in the amyloid driven pathology progression with high confidence, some of which are directly involved in the onset of mitochondrial apoptosis and may represent potential markers for use in human neurological diseases prognosis. Our results further contribute to identifying common pathological pathways involved in both aging and progressive neurodegenerative disorders enhancing the understanding of disease pathogenesis.

Caffeine increases mitochondrial function and blocks melatonin signaling to mitochondria in Alzheimer's mice and cells

Caffeine and melatonin have been shown to protect the Swedish mutant amyloid precursor protein (APPsw) transgenic mouse model of Alzheimer's disease from cognitive dysfunction. But their mechanisms of action remain incompletely understood. These Alzheimer's mice have extensive mitochondrial dysfunction, which likely contributes to their cognitive decline. To further explore the mechanism through which caffeine and melatonin protect cognitive function in these mice, we monitored the function of isolated mitochondria from APPsw mice treated with caffeine, melatonin, or both in their drinking water for one month. Melatonin treatment yielded a near complete restoration of mitochondrial function in assays of respiratory rate, membrane potential, reactive oxygen species production, and ATP levels. Caffeine treatment by itself yielded a small increase in mitochondrial function. However, caffeine largely blocked the large enhancement of mitochondrial function provided by melatonin. Studies with N2a neuroblastoma cells stably expressing APPsw showed that specific inhibition of cAMP-dependent phosphodiesterase (PDE) 4 or cGMP-dependent PDE5 also blocked melatonin protection of mitochondrial function, but A2a and A1 adenosine receptor antagonists were without effect. Melatonin or caffeine at the concentrations used to modulate mitochondrial function in the cells had no effect on cAMP-dependent PDE activity or cellular cAMP or cGMP levels. Therefore, caffeine and increased cyclic nucleotide levels likely block melatonin signaling to mitochondria by independent mechanisms that do not involve adenosine receptor antagonism. The results of this study indicate that melatonin restores mitochondrial function much more potently than caffeine in APPsw transgenic mouse and cell models of Alzheimer's disease.

C-Fos expression reveals aberrant neural network activity during cued fear conditioning in APPswe transgenic mice

The neural circuitry underlying emotional learning and memory is known to involve both the amygdala and hippocampus. Both of these structures undergo anatomical and functional changes during the course of Alzheimer’s disease. The present study used expression of the immediate early gene c-Fos to examine the effect of amyloid-induced synaptic pathology on neural activity in the hippocampus and amygdala immediately following Pavlovian fear conditioning. Tg2576 mice underwent cued fear conditioning and the regional interdependencies of c-Fos expression in the hippocampus and the amygdala were assessed using structural equation modelling. Tg2576 mice displayed normal acquisition of conditioned freezing to a punctate auditory cue paired with shock. However, the analysis of c-Fos expression indicated abnormal regional activity in the hippocampal dentate gyrus of Tg2576 mice. Structural equation modelling also supported the view that activity within the amygdala was independent of hippocampal activity in Tg2576 mice (unlike control mice) and regional interaction between the dentate gyrus and CA3 region was disrupted. The results provide novel insight into the effects of excess amyloid production on brain region interdependencies underpinning emotional learning.

Aminothiazoles as γ-secretase modulators

We herein report the discovery of a new γ-secretase modulator class with an aminothiazole core starting from a HTS hit (3). Synthesis and SAR of this series are discussed. These novel compounds demonstrate moderate to good in vitro potency in inhibiting amyloid beta (Aβ) peptide production. Overall γ-secretase is not inhibited but the formation of the aggregating, toxic Aβ42 peptide is shifted to smaller non-aggregating Aβ peptides. Compound 15 reduced brain Aβ42 in vivo in APPSwe transgenic mice at 30mg/kg p.o.

Effect of Huprine X on β-Amyloid, Synaptophysin and α7 Neuronal Nicotinic Acetylcholine Receptors in the Brain of 3xTg-AD and APPswe Transgenic Mice

Background: Several studies implicate acetylcholinesterase (AChE) in the pathogenesis of Alzheimer’s disease (AD), raising the question of whether inhibitors of AChE also might act in a disease-modifying manner. Huprine X (HX), a reversible AChE inhibitor hybrid of tacrine and huperzine A, has shown to affect the amyloidogenic process in vitro. In this study, the aim was to investigate whether HX could affect the AD-related neuropathology in vivoin two mouse models. Methods:Tg2576 (K670M/N671L) (APPswe) and 3xTg-AD (K670M/N671L, PS1M146V, tauP301L) mice were treated with HX (0.12 µmol/kg, i.p., 21 days) or saline at 6–7 months. Human β-amyloid (Aβ) was measured by ELISA, synaptophysin by Western blot and α7 neuronal nicotinic acetylcholine receptors (nAChRs) were analyzed by [¹²⁵I]α-bungarotoxin autoradiography. Results: Treatment with HX reduced insoluble Aβ1–40 (about 40%) in the hippocampus of 3xTg-AD mice, while showing no effect in APPswe mice. Additionally, HX markedly increased cortical synaptophysin levels (about 140%) and decreased (about 30%) the levels of α7 nAChRs in the caudate nucleus of 3xTg-AD mice, while increasing (about 10%) hippocampal α7 nAChRs in APPswe mice. Conclusion: The two mouse models react differently to HX treatment, possibly due to their differences in brain neuropathology. The modulation of Aβ and synaptophysin by HX in 3xTg-AD mice might be due to its suggested interaction with the peripheral anionic site on AChE, and/or via cholinergic mechanisms involving activation of cholinergic receptors. Our results provide further evidence that drugs targeting AChE affect some of the fundamental processes that contribute to neurodegeneration, but whether HX might act in a disease-modifying manner in AD patients remains to be proven.

Reduction of Aβ42 in brains of transgenic APPswe mice by 2‐3‐chlorophenylaminophenylacetate

1. Imbalanced generation of the Abeta42 peptide from the amyloid beta protein precursor (APP) is implicated in the pathogenesis of Alzheimer's disease. 2. The present study is the first to evaluate the ability of 2-[3-chlorophenylamino]phenylacetic acid (GLY-230), a new drug in clinical development for the treatment of vascular complications of diabetes, to modulate Abeta42 levels in transgenic mice expressing APP. 3. Oral administration of 7.5 mg/kg GLY-230 twice a day for 14 days to APPswe transgenic mice aged 3 months significantly reduced brain Abeta42 and increased plasma Abeta42 levels by 50 and 20%, respectively. 4. GLY-230 readily entered the brain after administration of a dose (7.5 mg/kg) that decreased brain Abeta42. 5. These results are the first to demonstrate that GLY-230, which exhibits antiglycation but no cyclo-oxygenase inhibitory properties, lowers brain Abeta42 levels in this experimental model of Alzheimer's disease.

Melatonin attenuates aβ amyloidosis induce tau hyperphosphorylation in transgenic mice Tg2576 of different ages

Key pathological hallmarks of Alzheimer's disease (AD) are the deposition of amyloid plaques containing Aβ-peptides and the formation of neurofibrillary tangles containing hyperphosphorylated tau. APPsw transgenic mice (Tg2576) overproducing mutant amyloid β protein precursor (βAPP) show substantial brain Aβ amyloidosis and behavioural abnormalities. In Tg2576, Aβ deposits induce phosphorylated tau accumulated at 8-10 months. Phosphorylated tau at Ser199, Thr231/Ser235, Thr205 and Ser404 accumulated in different ages. The major kinase for tau phosphorylation was GSK3β and CDK-5. The pineal and retinal melatonin regulates endogenous circadian rhythms, and has various physiological functions including neuromodulatory and vasoactive actions, antioxidative and neuroprotective properties. Our recent studies have demonstrated that melatonin efficiently attenuates Alzheimer-like tau hyperphosphorylation in Tg2576. Four-month-old (n=4-5)and Eight-month-old (n=4-5) Tg2576 animals (Tgs) were daily injections of melatonin (14mg/kg) for 4 months. Respective controls included non-transgenic littermates (Lts) (n=4-5), and untreated Tgs (n=4-5). After 4 months of treatment, Hyperphosphorylated tau, GSK-3β and CDK5 were determined by Western blotting, immunohistochemistry with specific antibodies. The long-term influence of melatonin on behavior, biochemical and neuropathologic changes in Tg2576. In Eight-month-old mice, Hyperphosphorylated tau epitopes were substantially decreased as assessed with the pT205 and pS404 antibodies in mel-treated Tg mice. The untreated Tg mice show increased levels of tau hyperphosphorylation and increased activated CDK5. In twelve-month-old mice, Hyperphosphorylated tau were substantially decreased as assessed with the pT231 antibodies in mel-treated Tg mice. The untreated Tg mice show, together with increased amyloidogenesis, increased levels of tau hyperphosphorylation and increased activated GSK-3β. Four months of Melatonin treatment reduced the burden of amyloid plaques and the levels of hyperphosphorylated tau. Melatonin reduced the activated CDK5 and GSK-3β respectively in 8 months and 12 months. Melatonin can exert multiple protective effects on both amyloidogenesis and tau hyperphosphorylation via regulate the activated CDK5 and GSK-3β in transgenic mice Tg2576 of different ages.