Virtual Screening and Testing of GSK-3 Inhibitors Using Human SH-SY5Y Cells Expressing Tau Folding Reporter and Mouse Hippocampal Primary Culture under Tau Cytotoxicity.

Glycogen synthase kinase-3ß (GSK-3ß) is an important serine/threonine kinase that implicates in multiple cellular processes and links with the neurodegenerative diseases including Alzheimer's disease (AD). In this study, structure-based virtual screening was performed to search database for compounds targeting GSK-3ß from Enamine's screening collection. Of the top-ranked compounds, 7 primary hits underwent a luminescent kinase assay and a cell assay using human neuroblastoma SH-SY5Y cells expressing Tau repeat domain (TauRD) with pro-aggregant mutation ΔK280. In the kinase assay for these 7 compounds, residual GSK-3ß activities ranged from 36.1% to 90.0% were detected at the IC50 of SB-216763. In the cell assay, only compounds VB-030 and VB-037 reduced Tau aggregation in SH-SY5Y cells expressing ΔK280 TauRD-DsRed folding reporter. In SH-SY5Y cells expressing ΔK280 TauRD, neither VB-030 nor VB-037 increased expression of GSK-3α Ser21 or GSK-3ß Ser9. Among extracellular signal-regulated kinase (ERK), AKT serine/threonine kinase 1 (AKT), mitogen-activated protein kinase 14 (P38) and mitogen-activated protein kinase 8 (JNK) which modulate Tau phosphorylation, VB-037 attenuated active phosphorylation of P38 Thr180/Tyr182, whereas VB-030 had no effect on the phosphorylation status of ERK, AKT, P38 or JNK. However, both VB-030 and VB-037 reduced endogenous Tau phosphorylation at Ser202, Thr231, Ser396 and Ser404 in neuronally differentiated SH-SY5Y expressing ΔK280 TauRD. In addition, VB-030 and VB-037 further improved neuronal survival and/or neurite length and branch in mouse hippocampal primary culture under Tau cytotoxicity. Overall, through inhibiting GSK-3ß kinase activity and/or p-P38 (Thr180/Tyr182), both compounds may serve as promising candidates to reduce Tau aggregation/cytotoxicity for AD treatment.

Lactobacillus plantarum PS128 prevents cognitive dysfunction in Alzheimer's disease mice by modulating propionic acid levels, glycogen synthase kinase 3 beta activity, and gliosis.

BACKGROUND: According to recent evidence, psychobiotics exert beneficial effects on central nervous system-related diseases, such as mental disorders. Lactobacillus plantarum PS128 (PS128), a novel psychobiotic strain, improves motor function, depression, and anxiety behaviors. However, the psychobiotic effects and mechanisms of PS128 in Alzheimer's disease (AD) remain to be explored. OBJECTIVES: The goal of the current study was to evaluate the beneficial effects of PS128 and to further elucidate its mechanism in AD mice. METHODS: PS128 (1010 colony-forming unit (CFU)/ml) was administered via oral gavage (o.g.) to 6-month-old male wild-type B6 and 3 × Tg-AD mice (harboring the PS1M146V, APPswe and TauP30IL transgenes) that received an intracerebroventricular injection of streptozotocin (icv-STZ, 3 mg/kg) or vehicle (saline) for 33 days. After serial behavioral tests, fecal short-chain fatty acid levels and AD-related pathology were assessed in these mice. RESULTS: Our findings show that intracerebroventricular injection of streptozotocin accelerated cognitive dysfunction associated with increasing levels of glycogen synthase kinase 3 beta (GSK3ß) activity, tau protein phosphorylation at the T231 site (pT231), amyloid-ß (Aß) deposition, amyloid-ß protein precursor (AßPP), ß-site AßPP-cleaving enzyme (BACE1), gliosis, fecal propionic acid (PPA) levels and cognition-related neuronal loss and decreasing postsynaptic density protein 95 (PSD95) levels in 3 × Tg-AD mice. PS128 supplementation effectively prevented the damage induced by intracerebroventricular injection of streptozotocin in 3 × Tg-AD mice. CONCLUSIONS: Based on the experimental results, intracerebroventricular injection of streptozotocin accelerates the progression of AD in the 3 × Tg-AD mice, primarily by increasing the levels of gliosis, which were mediated by the propionic acid and glycogen synthase kinase 3 beta pathways. PS128 supplementation prevents damage induced by intracerebroventricular injection of streptozotocin by regulating the propionic acid levels, glycogen synthase kinase 3 beta activity, and gliosis in 3 × Tg-AD mice. Therefore, we suggest that PS128 supplementation is a potential strategy to prevent and/or delay the progression of AD.

Prebiotic Lactulose Ameliorates the Cognitive Deficit in Alzheimer's Disease Mouse Model through Macroautophagy and Chaperone-Mediated Autophagy Pathways.

Lactulose, as a prebiotic, can be utilized by human gut microbiota and stimulate their growth. Although microbiota modulation has become an emerging approach to manage many diseases and can be achieved by the administration of prebiotics, fewer investigations have been carried out on the therapeutic mechanism of lactulose. Two trehalose analogs, lactulose and melibiose, were identified as having a neuroprotective effect in polyglutamine and Parkinson disease models. In this study, we examined lactulose and melibiose in a mouse primary hippocampal neuronal culture under the toxicity of oligomeric Aß25-35. Lactulose was further tested in vivo because its effective concentration is lower than that of melibiose. Lactulose and trehalose were applied individually to mice before a bilateral intrahippocampal CA1 injection of oligomeric Aß25-35. The administration of lactulose and trehalose attenuated the short-term memory and the learning retrieval of Alzheimer's disease (AD) mice. From a pathological analysis, we found that the pretreatment of lactulose and trehalose decreased neuroinflammation and increased the levels of the autophagic pathways. These results suggest that the neuroprotective effects of both lactulose and trehalose are achieved through anti-inflammation and autophagy. In addition, lactulose was better than trehalose in the enhancement of the synaptic protein expression level in AD mice. Therefore, lactulose could potentially be developed into a preventive and/or therapeutic disaccharide for AD.

LMDS-1, a potential TrkB receptor agonist provides a safe and neurotrophic effect for early-phase Alzheimer's disease.

RATIONALE: The signaling pathways of tropomyosin-related kinase B (TrkB) receptor play a pivotal role in axonal sprouting, proliferation of dendritic arbor, synaptic plasticity, and neuronal differentiation. The levels of BDNF and TrkB receptor were reduced in patients with Alzheimer's disease (AD). OBJECTIVES: The activation of TrkB signaling pathways is a potential strategy for AD therapies. We intended to identify potential TrkB agonists to activate the neuroprotective signaling to alleviate the pathological features of AD mice. RESULTS: Both of the Aß-deteriorated hippocampal primary neurons and mouse models were generated and showed AD characteristics. We first investigated 12 potential TrkB agonists with primary hippocampal neurons of mice. Both 7,8-DHF and LMDS-1 were identified to have better effect than the other compounds on dendritic arborization of the neurons and were further applied to the Aß-injected mouse model. The short-term cognitive behavior and pathology in the mice were improved by LMDS-1. Further investigation indicated that LMDS-1 activated the TrkB through phosphorylation at Y516 rather than Y816. In addition, the ERK but not CaMKII or Akt was activated in the mouse hippocampus with LMDS-1 administration. LMDS-1 treatment also upregulated CREB and BDNF while downregulated the GSK3ß active form and tau phosphorylation. CONCLUSIONS: This study suggests that LMDS-1 upregulates the expression of BDNF and ameliorates the early-phase phenotypes of the AD-like mice through the pTrkB (Y516)-ERK-CREB pathway. In addition, LMDS-1 has better effect than 7,8-DHF in ameliorating the behavioral and pathological features of AD-like mice.

Targeting Inflammation, PHA-767491 Shows a Broad Spectrum in Protein Aggregation Diseases.

Many protein aggregation diseases (PAD) affect the nervous system. Deposits of aggregated disease-specific proteins are found within or around the neuronal cells of neurodegenerative diseases. Although the main protein component is disease-specific, oligomeric aggregates are presumed to be the key agents causing the neurotoxicity. Evidence has shown that protein aggregates cause a chronic inflammatory reaction in the brain, resulting in neurodegeneration. Therefore, strategies targeting anti-inflammation could be beneficial to the therapeutics of PAD. PHA-767491 was originally identified as an inhibitor of CDC7/CDK9 and was found to reduce TDP-43 phosphorylation and prevent neurodegeneration in TDP-43 transgenic animals. We recently identified PHA-767491 as a GSK-3ß inhibitor. In this study, we established mouse hippocampal primary culture with tau-hyperphosphorylation through the activation of GSK-3ß using Wortmannin and GF109203X. We found that PHA-767491 significantly improved the neurite outgrowth of hippocampal primary neurons against the neurotoxicity induced by GSK-3ß. We further showed that PHA-767491 had neuroprotective ability in hippocampal primary culture under oligomeric Aß treatment. In addition, PHA-767491 attenuated the neuroinflammation in mouse cerebellar slice culture with human TBP-109Q agitation. Further study of SCA17 transgenic mice carrying human TBP-109Q showed that PHA-767491 ameliorated the gait ataxia and the inflammatory response both centrally and peripherally. Our findings suggest that PHA-767491 has a broad spectrum of activity in the treatment of different PAD and that this activity could be based on the anti-inflammation mechanism.

Puerariae Radix Prevents Anxiety and Cognitive Deficits in Mice Under Oligomeric Aß-Induced Stress.

To evaluate the therapeutic effects of Chinese herbal medicine (CHM) for Alzheimer's disease (AD), we evaluated five CHMs in oligomeric Aß25-35-treated mouse primary hippocampal neuronal cultures. The aqueous extract from the root of Pueraria lobata (Puerariae Radix; PR) showed better neuroprotective effects than did the other four CHM aqueous extracts, including Gardenia jasminoides, Eleutherococcus senticosus, Rhodiola rosea, and Panax, in the primary culture treated with saline or oligomeric Aß25-35. Furthermore, the neuroprotective effects of aqueous extract of PR were also better than its well-known active compound, puerarin, against the neurotoxicity of oligomeric Aß25-35 in a primary culture. For in vivo experiments, C57BL/6J male mice that received direct infusion of soluble oligomeric Aß25-35 into the bilateral hippocampal CA1 subregion were used as an alternative AD mouse model. The effects and molecular mechanisms of chronic systemic administration of PR aqueous extract were evaluated in the alternative AD model. PR aqueous extract prevented anxiety and cognitive impairment in mice associated with a decrease in the levels of Aß deposition, tau protein phosphorylation, inflammation, loss of noradrenergic, and serotonergic neurons and an increase in the levels of synaptophysin and insulin degrading enzyme (IDE) against the toxicity of oligomeric Aß25-35. Furthermore, no obvious damage to the liver and kidney was detected after chronic systemic administration of PR aqueous extract. Therefore, using PR could be a safer, more effective therapeutic strategy than using its active compound puerarin to prevent both cognitive and noncognitive dysfunction and related pathological features of AD.

Indole Compound NC009-1 Augments APOE and TRKA in Alzheimer's Disease Cell and Mouse Models for Neuroprotection and Cognitive Improvement.

Alzheimer's disease (AD), associated with abnormal accumulation of amyloid-ß (Aß), is the most common cause of dementia among older people. A few studies have identified substantial AD biomarkers in blood but their results were inconsistent. Here we screened gene expression alterations on Aß-GFP SH-SY5Y neuronal model for AD, and evaluated the findings on peripheral leukocytes from 78 patients with AD and 56 healthy controls. The therapeutic responses of identified biomarker candidates were further examined in Aß-GFP SH-SY5Y neuronal and APP/PS1/Tau triple transgenic (3×Tg-AD) mouse models. Downregulation of apolipoprotein E (APOE) and tropomyosin receptor kinase A (TRKA) were detected in Aß-GFP SH-SY5Y cells and validated by peripheral leukocytes from AD patients. Treatment with an in-house indole compound NC009-1 upregulated the expression of APOE and TRKA accompanied with improvement of neurite outgrowth in Aß-GFP SH-SY5Y cells. NC009-1 further rescued the downregulated APOE and TRKA and reduced Aß and tau levels in hippocampus and cortex, and ameliorated cognitive deficits in streptozocin-induced hyperglycemic 3×Tg-AD mice. These results suggest the role of APOE and TRKA as potential peripheral biomarkers in AD, and offer a new drug development target of AD treatment. Further studies of a large series of AD patients will be warranted to verify the findings and confirm the correlation between these markers and therapeutic efficacy.

MGCD0103, a selective histone deacetylase inhibitor, coameliorates oligomeric Aß25-35 -induced anxiety and cognitive deficits in a mouse model.

AIMS: Recently, histone deacetylase (HDAC) inhibitors are considered a possible therapeutic strategy in Alzheimer's disease (AD). However, HDACi treatments exhibit diverse functions with unfavorable effects in AD. Thus, the development of selective HDACi without side effects is urgently needed. METHODS: HDACi, namely, BML210, MGCD0103, PXD101, and Droxinostat, were screened in mouse hippocampal primary cultures incubated with oligomeric Aß25-35 (50 µmol/L). MGCD0103 was chosen for in vivo tests and was intraperitoneally injected into C57BL/6J mice (0.5 mg/kg, once per day) for 4 weeks following an intrahippocampal CA1 injection of oligomeric Aß25-35 . Brain samples were collected for pathological analyses after the behavioral analyses including open- field test (OFT), elevated plus maze (EPM), Y-maze, and Morris water maze (MWM). RESULTS: Among the HDACi, MGCD0103 exhibited significant neuroprotection against the Aß toxicity in primary cultures. MGCD0103 coattenuated cognitive deficits and anxiety against Aß damage in mice. MGCD0103 further ameliorated pathological features such as the levels of acetylated histone 3 at Lys 9 site (H3K9) and α-tubulin, synaptophysin, Aß, tau protein phosphorylation, and serotonergic neuron loss against Aß toxicity. Furthermore, chronic MGCD0103 treatment did not show liver or kidney toxicity in mice. CONCLUSIONS: These results reveal MGCD0103 could be a potential therapeutic agent against AD.

Chronic low dose of AM404 ameliorates the cognitive impairment and pathological features in hyperglycemic 3xTg-AD mice.

RATIONALE: Hyperglycemia accelerates the progression of Alzheimer's disease (AD), and GSK3ß plays a potential link between AD and hyperglycemia. Therefore, a direct or indirect GSK3ß inhibition may have potential to delay the progression of AD. Our previous biochemical assay identified AM404 as a GSK3ß inhibitor at high dose (IC50 = 5.353 µM); however, other study suggests that AM404 impaired synaptic plasticity of hippocampus at high dose (10 mg/kg; i.p.). Therefore, the dose and duration of treatment are crucial for the effects of AM404. OBJECTIVE: The effects and molecular mechanisms of AM404 at low dose were evaluated from in vitro to in vivo models. METHODS: AM404 (0.1-0.5 µM) was tested on tau hyperphosphorylated mouse hippocampal primary cultures treated with Wortmannin (WT) and GF109203X (GFX). Hyperglycemic triple transgenic AD (3×Tg-AD) mice at 6 months old were intraperitoneally injected with AM404 (0.25 mg/kg) for 4 weeks. The spatial learning and memory of mice were measured using the Morris water maze. Mouse brain and serum samples were collected for pathological analyses. RESULTS: AM404 (0.5 µM) exhibited significantly augmented neuroprotection toward tau hyperphosphorylation in primary cultures. The chronic systemic administration of AM404 (0.25 mg/kg) attenuated cognitive deficits in hyperglycemic 3×Tg-AD mice. Moreover, chronic low dose of AM404 significantly attenuated Aß production, tau protein phosphorylation, and inflammation associated with an increase of pS473Akt and pS9-GSK3ß. Therefore, AM404 at low dose, not only increased neuroprotection, but also ameliorated cognitive deficit, could be partly by regulating the Akt/GSK3ß signaling, which may contribute to downregulation of Aß, tau hyperphosphorylation, and inflammation in hyperglycemic 3×Tg-AD mice. CONCLUSIONS: These results highlight that chronic administration of AM404 at low dose may be through the Akt/GSK3ß pathway to ameliorate the impairment in hyperglycemic 3×Tg-AD mice.

Administration of Momordica charantia Enhances the Neuroprotection and Reduces the Side Effects of LiCl in the Treatment of Alzheimer's Disease.

Recently, the use of natural food supplements to reduce the side effects of chemical compounds used for the treatment of various diseases has become popular. Lithium chloride (LiCl) has some protective effects in neurological diseases, including Alzheimer's disease (AD). However, its toxic effects on various systems and some relevant interactions with other drugs limit its broader use in clinical practice. In this study, we investigated the in vitro and in vivo pharmacological functions of LiCl combined with Momordica charantia (MC) in the treatment of AD. The in vitro results show that the order of the neuroprotective effect is MC5, MC3, MC2, and MC5523 under hyperglycemia or tau hyperphosphorylation. Therefore, MC5523 (80 mg/kg; oral gavage) and/or LiCl (141.3 mg/kg; intraperitoneal injection) were applied to ovariectomized (OVX) 3×Tg-AD female and C57BL/6J (B6) male mice that received intracerebroventricular injections of streptozotocin (icv-STZ, 3 mg/kg) for 28 days. We found that the combined treatment not only increased the survival rate by reducing hepatotoxicity but also increased neuroprotection associated with anti-gliosis in the icv-STZ OVX 3×Tg-AD mice. Furthermore, the cotreatment with MC5523 and LiCl prevented memory deficits associated with reduced neuronal loss, gliosis, oligomeric Aß level, and tau hyperphosphorylation and increased the expression levels of synaptic-related protein and pS9-GSK3ß (inactive form) in the icv-STZ B6 mice. Therefore, MC5523 combined with LiCl could be a potential strategy for the treatment of AD.

The Potential of Indole/Indolylquinoline Compounds in Tau Misfolding Reduction by Enhancement of HSPB1.

BACKGROUND: Neurofibrillary tangles formed from tau misfolding have long been considered one of the pathological hallmarks of Alzheimer's disease (AD). The misfolding of tau in AD correlates with the clinical progression of AD and inhibition or reversal of tau misfolding may protect the affected neurons. METHODS: We generated 293 and SH-SY5Y cells expressing DsRed-tagged pro-aggregation mutant of repeat domain of tau (ΔK280 tauRD ) to test indole/indolylquinoline derivatives for reducing tau misfolding and neuroprotection. RESULTS: Four of the 10 derivatives tested displayed good misfolding-inhibitory effects on Tet-On 293 cells. Among them, NC009-1 and NC009-7 enhanced heat-shock 27 kDa protein 1 (HSPB1) expression to increase ∆K280 tauRD -DsRed solubility and promoted neurite outgrowth in Tet-On SH-SY5Y cells. Knockdown of HSPB1 resulted in decreased ∆K280 tauRD -DsRed solubility and reduced neurite outgrowth, which were rescued by addition of NC009-1/NC009-7. Treatment with indole/indolylquinoline derivatives also improved neuronal cell viability and neurite outgrowth in mouse hippocampal primary culture under tau cytotoxicity. CONCLUSION: Our results demonstrate how indole/indolylquinoline derivatives are likely to work in tau misfolding reduction, providing insight into the possible working mechanism of indole and indolylquinoline derivatives in AD treatment.

Targeting the prodromal stage of spinocerebellar ataxia type 17 mice: G-CSF in the prevention of motor deficits via upregulating chaperone and autophagy levels.

Spinocerebellar ataxia type 17 (SCA17), an autosomal dominant cerebellar ataxia, is a devastating, incurable disease caused by the polyglutamine (polyQ) expansion of transcription factor TATA binding protein (TBP). The polyQ expansion causes misfolding and aggregation of the mutant TBP, further leading to cytotoxicity and cell death. The well-recognized prodromal phase in many forms of neurodegeneration suggests a prolonged period of partial neuronal dysfunction prior to cell loss that may be amenable to therapeutic intervention. The objective of this study was to assess the effects and molecular mechanisms of granulocyte-colony stimulating factor (G-CSF) therapy during the pre-symptomatic stage in SCA17 mice. Treatment with G-CSF at the pre-symptomatic stage improved the motor coordination of SCA17 mice and reduced the cell loss, insoluble mutant TBP protein, and vacuole formation in the Purkinje neurons of these mice. The neuroprotective effects of G-CSF may be produced by increases in Hsp70, Beclin-1, LC3-II and the p-ERK survival pathway. Upregulation of chaperone and autophagy levels further enhances the clearance of mutant protein aggregation, slowing the progression of pathology in SCA17 mice. Therefore, we showed that the early intervention of G-CSF has a neuroprotective effect, delaying the progression of SCA17 in mutant mice via increases in the levels of chaperone expression and autophagy.

The potential of synthetic indolylquinoline derivatives for Aß aggregation reduction by chemical chaperone activity.

Alzheimer's disease (AD) is the most prevalent form of dementia associated with progressive cognitive decline and memory loss. Extracellular ß-amyloid (Aß) is a major constituent of senile plaques, one of the pathological hallmarks of AD. Aß deposition causes neuronal death via a number of possible mechanisms such as increasing oxidative stress. Therefore therapeutic approaches to identify novel Aß aggregate reducers could be effective for AD treatment. Using a Trx-His-Aß biochemical assay, we screened 11 synthetic indolylquinoline compounds, and found NC009-1, -2, -6 and -7 displaying potential to reduce Aß aggregation. Treating Tet-On Aß-GFP 293 cells with these compounds reduced Aß aggregation and reactive oxygen species. These compounds also promoted neurite outgrowth in Tet-On Aß-GFP SH-SY5Y cells. Furthermore, treatment with above compounds improved neuronal cell viability, neurite outgrowth, and synaptophysin expression level in mouse hippocampal primary culture under oligomeric Aß-induced cytotoxicity. Moreover, the tested NC009-1 significantly ameliorated Aß-induced inhibition of hippocampal long-term potentiation in mouse hippocampal slices. Our results demonstrate how synthetic indolylquinoline compounds are likely to work as chemical chaperones in Aß-aggregation reduction and neuroprotection, providing insight into the possible applications of indolylquinoline compounds in AD treatment.

Administration of NaHS Attenuates Footshock-Induced Pathologies and Emotional and Cognitive Dysfunction in Triple Transgenic Alzheimer's Mice.

Alzheimer's disease (AD) is characterized by progressive cognitive decline and neuropsychiatric symptoms. Increasing evidence indicates that environmental risk factors in young adults may accelerate cognitive loss in AD and that Hydrogen Sulfide (H2S) may represent an innovative treatment to slow the progression of AD. Therefore, the aim of this study was to evaluate the effects of NaHS, an H2S donor, in a triple transgenic AD mouse model (3×Tg-AD) under footshock with situational reminders (SRs). Inescapable footshock with SRs induced anxiety and cognitive dysfunction as well as a decrease in the levels of plasma H2S and GSH and an increase in IL-6 levels in 3×Tg-AD mice. Under footshock with SR stimulus, amyloid deposition, tau protein hyperphosphorylation, and microgliosis were highly increased in the stress-responsive brain structures, including the hippocampus and amygdala, of the AD mice. Oxidative stress, inflammatory response, and ß-site APP cleaving enzyme 1 (BACE1) levels were also increased, and the level of inactivated glycogen synthase kinase-3ß (GSK3ß) (pSer9) was decreased in the hippocampi of AD mice subjected to footshock with SRs. Furthermore, the numbers of cholinergic neurons in the medial septum/diagonal band of Broca (MS/DB) and noradrenergic neurons in the locus coeruleus (LC) were also decreased in the 3×Tg-AD mice under footshock with SRs. These biochemical hallmarks and pathological presentations were all alleviated by the semi-acute administration of NaHS in the AD mice. Together, these findings suggest that footshock with SRs induces the impairment of spatial cognition and emotion, which involve pathological changes in the peripheral and central systems, including the hippocampus, MS/DB, LC, and BLA, and that the administration of NaHS may be a candidate strategy to ameliorate the progression of neurodegeneration.

Trehalose attenuates the gait ataxia and gliosis of spinocerebellar ataxia type 17 mice.

Spinocerebellar ataxia type 17 (SCA17) is caused by CAG/CAA repeat expansion on the gene encoding a general transcription factor, TATA-box-binding protein (TBP). The CAG repeat expansion leads to the reduced solubility of polyglutamine TBP and induces aggregate formation. The TBP aggregation, mostly present in the cell nuclei, is distinct from that in most other neurodegenerative diseases, in which the aggregation is formed in cytosol or extracellular compartments. Trehalose is a disaccharide issued by the Food and Drug Administration with a Generally Recognized As Safe status. Lines of evidence suggest trehalose could prevent protein aggregate formation in several neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and Huntington's disease. In this study, we evaluated the therapeutic potential of trehalose on SCA17 using cerebellar primary and organotypic culture systems and a mouse model. Our results showed that TBP nuclear aggregation was significantly decreased in both the primary and slice cultures. Trehalose (4 %) was further supplied in the drinking water of SCA17 transgenic mice. We found both the gait behavior in the footprint analysis and motor coordination in the rotarod task were significantly improved in the trehalose-treated SCA17 mice. The cerebellar weight was increased and the astrocyte gliosis was reduced in SCA17 mice after trehalose treatment. These data suggest that trehalose could be a potential nontoxic treatment for SCA17.

Multifunctional Effects of Mangosteen Pericarp on Cognition in C57BL/6J and Triple Transgenic Alzheimer's Mice.

Mangosteen- (Garcinia mangostana-) based nutraceutical compounds have long been reported to possess multiple health-promoting properties. The current study investigated whether mangosteen pericarp (MP) could attenuate cognitive dysfunction. First, we found that treatment with MP significantly reduced the cell death and increased the brain-derived neurotrophic factor (BDNF) level in an organotypic hippocampal slice culture (OHSC). We then investigated the effects of age and MP diet on the cognitive function of male C57BL/6J (B6) mice. After 8-month dietary supplementation, the MP diet (5000 ppm) significantly attenuated the cognitive impairment associated with anti-inflammation, increasing BDNF level and decreasing p-tau (phospho-tau S202) in older B6 mice. We further applied MP dietary supplementation to triple transgenic Alzheimer's disease (3×Tg-AD) mice from 5 to 13 months old. The MP diet exerted neuroprotective, antioxidative, and anti-inflammatory effects and reduced the Aß deposition and p-tau (S202/S262) levels in the hippocampus of 3×Tg-AD mice, which might further attenuate the deficit in spatial memory retrieval. Thus, these results revealed that the multifunctional properties of MP might offer a promising supplementary diet to attenuate cognitive dysfunction in AD.

Exendin-4 protected against cognitive dysfunction in hyperglycemic mice receiving an intrahippocampal lipopolysaccharide injection.

BACKGROUND: Chronic hyperglycemia-associated inflammation plays critical roles in disease initiation and the progression of diabetic complications, including Alzheimer's disease (AD). However, the association of chronic hyperglycemia with acute inflammation of the central nervous system in the progression of AD still needs to be elucidated. In addition, recent evidence suggests that Glucagon-like peptide-1 receptor (GLP-1R) protects against neuronal damage in the brain. Therefore, the neuroprotective effects of the GLP-1R agonist exendin-4 (EX-4) against hyperglycemia/lipopolysaccharides (LPS) damage were also evaluated in this study. METHODOLOGY/PRINCIPAL FINDINGS: Ten days after streptozotocin (STZ) or vehicle (sodium citrate) treatment in mice, EX-4 treatment (10 µg/kg/day) was applied to the mice before intrahippocampal CA1 injection of LPS or vehicle (saline) and continued for 28 days. This study examined the molecular alterations in these mice after LPS and EX4 application, respectively. The mouse cognitive function was evaluated during the last 6 days of EX-4 treatment. The results showed that the activation of NF-κB-related inflammatory responses induced cognitive dysfunction in both the hyperglycemic mice and the mice that received acute intrahippocampal LPS injection. Furthermore, acute intrahippocampal LPS injection exacerbated the impairment of spatial learning and memory through a strong decrease in monoaminergic neurons and increases in astrocytes activation and apoptosis in the hyperglycemic mice. However, EX-4 treatment protected against the cognitive dysfunction resulting from hyperglycemia or/and intrahippocampal LPS injection. CONCLUSIONS/SIGNIFICANCE: These findings reveal that both hyperglycemia and intrahippocampal LPS injection induced cognitive dysfunction via activation of NF-κB-related inflammatory responses. However, acute intrahippocampal LPS injection exacerbated the progression of cognitive dysfunction in the hyperglycemic mice via a large increase in astrocytes activation-related responses. Furthermore, EX-4 might be considered as a potential adjuvant entity to protect against neurodegenerative diseases.

Selective improvement of cognitive function in adult and aged APP/PS1 transgenic mice by continuous non-shock treadmill exercise.

Exercise may contribute to prevention of the cognitive decline and delay the onset of the Alzheimer's disease (AD). We evaluated the effects of continuous non-shock treadmill exercise in adult and aged male APP/PS1 double mutant transgenic mice. Adult (7-8 month-old) and aged (24 month-old) male APP/PS1 transgenic and wild-type mice were randomly assigned to either sedentary or exercise groups. The exercise program included a one-week treadmill acclimatization to adapt to the novel environment. After acclimation, mice ran on a treadmill 5 days/week until sacrificed for pathological analyses. During exercise training, no tail shock was used in the exercise paradigm; only gentle tail touching was used to induce the mice to run, to minimize the stress otherwise associated with treadmill exercise. We found that the exercise program selectively improved the spatial learning and memory associated with an increase in both cholinergic neurons in the medial septum (MS)/vertical diagonal band (VDB) and serotonergic neurons in the raphe nucleus of aged APP/PS1 transgenic mice. In adult APP/PS1 transgenic mice, the exercise paradigm increased exploratory activity and reduced anxiety with an associated increase in numbers of serotonergic neurons in the raphe nucleus. In addition, the exercise paradigm also reduced amyloid-ß peptide (Aß) levels and microglia activation, but not enough to reduce the plaque loading in the hippocampus of the APP/PS1 transgenic mice. Therefore, these findings suggest that there may exist an age-related difference in the effect of continuous non-shock treadmill exercise training on AD.

Long-term social isolation exacerbates the impairment of spatial working memory in APP/PS1 transgenic mice.

The interaction between gene and environment is known to play a major role in the etiology of several neuropsychiatric disorders, including Alzheimer's disease (AD). The present study evaluated whether environmental manipulations such as social isolation may affect the genetic predisposition to accelerate the onset of AD-related symptoms in an adult APP/PS1 double mutant transgenic mouse model. Transgenic and wild-type male mice were housed either singly or in groups from the age of 3 months, and their behavior was compared at 7 months. Isolation had several effects on the APP/PS1 transgenic mice, including exacerbating the impairment of spatial working memory associated with increased Aß42/Aß40 ratio in the hippocampus; increased levels of MnSOD in the CA1-CA3 subregions of the hippocampus, basolateral part of the amygdala (BLA), and locus coeruleus (LC); and decreased numbers of cholinergic cells in the diagonal band of Broca (DB), noradrenergic neurons in LC, serotonergic neurons in the Raphe nucleus, and levels of NMDA 2B receptor (NR2B) in the hippocampus region. Our findings demonstrate the susceptibility of APP/PS1 transgenic adult male mice to environmental manipulation and show that social isolation has remarkable effects on the genetically determined AD-like symptoms.