lithium-chloride and Alzheimer-Disease

Accumulated evidence suggests that sporadic cases of Alzheimer's disease (AD) make up more than 95% of total AD patients, and diabetes has been implicated as a strong risk factor for the development of AD. Diabetes shares pathological features of AD, such as impaired insulin signaling, increased oxidative stress, increased amyloid-beta (Aβ) production, tauopathy and cerebrovascular complication. Due to shared pathologies between the two diseases, anti-diabetic drugs may be a suitable therapeutic option for AD treatment. In this article, we will discuss the well-known pathologies of AD, including Aβ plaques and tau tangles, as well as other mechanisms shared in AD and diabetes including reactive glia and the breakdown of blood brain barrier in order to evaluate the presence of any potential, indirect or direct links of pre-diabetic conditions to AD pathology. In addition, clinical evidence of high incidence of diabetic patients to the development of AD are described together with application of anti-diabetic medications to AD patients.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Astrocytes; Brain; Cerebrovascular Disorders; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Lithium Chloride; Pioglitazone

Systems pharmacology is a novel framework for drug research that models traditional and innovative pharmacological parameters and provides the overall efficacy and safety profile of a drug across body systems and complex, non-linear, molecular interactions. Lithium chloride, a pharmacological compound approved for the therapy of psychiatric disorders, represents a poorly explored compound for the treatment of Alzheimer's disease (AD). Lithium has been shown to reduce downstream effects associated with the aberrant overactivation of certain molecular pathways, such as glycogen synthase kinase 3 subunit β (GSK3-β)-related pathways, involved in AD-related pathophysiology. It seems that overactivation and overexpression of GSK3-β lead to an impairment of long-term potentiation and amyloid-β induced neurotoxicity that can be normalized using lithium. Moreover, a growing body of evidence has demonstrated that lithium's GSK3-β inhibitory effect prevents tau phosphorylation in mouse models of tauopathies. Clinical data have been inconclusive, partly due to methodological limitations. The lack of studies exploring the dynamics of protein misfolding in AD and investigating the specific tau-isoforms appearing prior to the accumulation of neurofibrillary tangles calls for new and optimized clinical trials. Advanced computer modeling based on a formal implementation of quantitative parameters and basic enzymatic insights into a mechanism-based model would present a good start to tackle these non-linear interactions. This innovative approach will pave the way for developing "molecularly" biomarker-guided targeted therapies, i.e., treatments specifically adapted ("tailored") to the individual, consistently with the primary objectives and key conceptual points of precision medicine and precision pharmacology.

Topics: Alzheimer Disease; Animals; Antimanic Agents; Glycogen Synthase Kinase 3 beta; Humans; Lithium Chloride; Metabolic Networks and Pathways

Glycogen synthase kinase-3β (GSK-3β), a serine/threonine protein kinase, has been reported to show essential roles in molecular pathophysiology of many diseases. Mitochondrion is a dynamic organelle for producing cellular energy and determining cell fates. Stress-induced translocated GSK-3β may interact with mitochondrial proteins, including PI3K-Akt, PGC-1α, HK II, PKCε, components of respiratory chain, and subunits of mPTP. Mitochondrial pool of GSK-3β has been implicated in mediation of mitochondrial functions. GSK-3β exhibits the regulatory effects on mitochondrial biogenesis, mitochondrial bioenergetics, mitochondrial permeability, mitochondrial motility, and mitochondrial apoptosis. The versatile functions of GSK-3β might be associated with its wide range of substrates. Accumulative evidence demonstrates that GSK-3β inactivation may be potentially developed as the promising strategy in management of many diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD). Intensive efforts have been made for exploring GSK-3β inhibitors. Natural products provide us a great source for screening new lead compounds in inactivation of GSK-3β. The key roles of GSK-3β in mediation of mitochondrial functions are discussed in this review.

Topics: Alzheimer Disease; Animals; Apoptosis; Biological Products; Glycogen Synthase Kinase 3 beta; Lithium Chloride; Membrane Potential, Mitochondrial; Mitochondria; Mitochondrial Proteins

Trisomy 21 and the consequent extra copy of the amyloid precursor protein (APP) gene and increased beta-amyloid (Aβ) peptide production underlie the universal development of Alzheimer's disease (AD) pathology and high risk of AD dementia in people with Down syndrome (DS). Trisomy 21 and other forms of aneuploidy also arise among neurons and peripheral cells in both sporadic and familial AD and in mouse and cell models thereof, reinforcing the conclusion that AD and DS are two sides of the same coin. The demonstration that 90% of the neurodegeneration in AD can be attributed to the selective loss of aneuploid neurons generated over the course of the disease indicates that aneuploidy is an essential feature of the pathogenic pathway leading to the depletion of neuronal cell populations. Trisomy 21 mosaicism also occurs in neurons and other cells from patients with Niemann-Pick C1 disease and from patients with familial or sporadic frontotemporal lobar degeneration (FTLD), as well as in their corresponding mouse and cell models. Biochemical studies have shown that Aβ induces mitotic spindle defects, chromosome mis-segregation, and aneuploidy in cultured cells by inhibiting specific microtubule motors required for mitosis. These data indicate that neuronal trisomy 21 and other types of aneuploidy characterize and likely contribute to multiple neurodegenerative diseases and are a valid target for therapeutic intervention. For example, reducing extracellular calcium or treating cells with lithium chloride (LiCl) blocks the induction of trisomy 21 by Aβ. The latter finding is relevant in light of recent reports of a lowered risk of dementia in bipolar patients treated with LiCl and in the stabilization of cognition in AD patients treated with LiCl.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Cell Cycle; Chromosomes, Human, Pair 21; Humans; Lithium Chloride; Mice; Mosaicism; Neurons; Presenilin-1; Trisomy; Uniparental Disomy

Alzheimer's disease (AD) is characterised by deposition of a 4 kDa amyloid-beta peptide (Abeta) into senile plaques of the affected brain. Abeta is a proteolytic product of the membrane protein, amyloid precursor protein (APP). An alternative cleavage pathway involves alpha-secretase activity and results in secretion of a 100 kDa non-amyloidogenic APP (sAPPalpha) and therefore a potential reduction in Abeta secretion. We have shown that estrogen induces alpha-cleavage and therefore results in the secretion of sAPPalpha. This secretion is signalled via MAP-kinase and PI-3 kinase signal-transduction pathways. These pathways also have the potential to inhibit the activation of glycogen synthase kinase 3beta (GSK), a protein involved in cell death. Therefore, the aim of this work was to further elucidate the estrogen-mediated signaling pathways involved in APP processing, with particular emphasis on GSK activity. By stimulating rat hypothalamic neuronal GT1-7 cells with estradiol, we found that estrogen decreases the activation state of GSK via the MAP kinase pathway. Moreover, the inhibition of GSK activity by LiCl causes enhanced sAPPalpha secretion in a pattern similar to that seen in response to estrogen, suggesting a pivotal role for this deactivation in APP processing. Further, inactivation of GSK by estrogen can be confirmed in an in vivo model. Elucidation of the signaling pathways involved in APP processing may help to understand the pathology of AD and may also prove beneficial in developing therapeutic strategies to combat AD.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Brain; Cell Death; Estrogens; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Humans; Lithium Chloride; MAP Kinase Signaling System; Models, Biological; Peptides; Phosphatidylinositol 3-Kinases; Signal Transduction

A lower incidence of dementia in bipolar patients treated with lithium has been described. This metal inhibits the phosphorylation of glycogen-synthase-kinase 3-α and β, which are related to amyloid precursor protein processing and tau hyperphosphorylation in pathological conditions, respectively. Following the same rationale, a group just found that lithium has disease-modifying properties in amnestic mild cognitive impairment with potential clinical implications for the prevention of Alzheimer's Disease (AD) when a dose ranging from 150 to 600 mg is used. As lithium is highly toxic in regular doses, our group evaluated the effect of a microdose of 300 μg, administered once daily on AD patients for 15 months. In the evaluation phase, the treated group showed no decreased performance in the mini-mental state examination test, in opposition to the lower scores observed for the control group during the treatment, with significant differences starting three months after the beginning of the treatment, and increasing progressively. This data suggests the efficacy of a microdose lithium treatment in preventing cognitive loss, reinforcing its therapeutic potential to treat AD using very low doses.

Topics: Adjuvants, Immunologic; Aged; Alzheimer Disease; Analysis of Variance; Cognition Disorders; Double-Blind Method; Female; Humans; Lithium Chloride; Male; Psychiatric Status Rating Scales

Topics: Alzheimer Disease; Cell Line; Cell Proliferation; Dose-Response Relationship, Drug; Drug Design; Dyrk Kinases; Glycogen Synthase Kinase 3 beta; Harmine; Humans; Models, Molecular; Molecular Structure; Neuroprotective Agents; Protein Kinase Inhibitors; Protein Serine-Threonine Kinases; Protein-Tyrosine Kinases; Structure-Activity Relationship

To target the multi-facets of Alzheimer's disease (AD), a series of novel GSK-3β inhibitors containing the 2,3-diaminopyridine moiety were designed and synthesized. The amide derivatives 5a-f showed moderate potency against GSK-3β with weak Cu

Topics: Alzheimer Disease; Amides; Amines; Animals; Antioxidants; Blood-Brain Barrier; Cell Line; Chelating Agents; Drug Design; Glycogen Synthase Kinase 3 beta; Humans; PC12 Cells; Protein Aggregation, Pathological; Protein Kinase Inhibitors; Rats; Structure-Activity Relationship; tau Proteins

Lithium (Li) is a medication long-used to treat bipolar disorder. It is currently under investigation for multiple nervous system disorders, including Alzheimer's disease (AD). While perturbation of RNA levels by Li has been previously reported, its effects on the whole transcriptome has been given little attention. We, therefore, sought to determine comprehensive effects of Li treatment on RNA levels. We cultured and differentiated human neuroblastoma (SK-N-SH) cells to neuronal cells with all-trans retinoic acid (ATRA). We exposed cultures for one week to lithium chloride or distilled water, extracted total RNA, depleted ribosomal RNA and performed whole-transcriptome RT-sequencing. We analyzed results by RNA length and type. We further analyzed expression and protein interaction networks between selected Li-altered protein-coding RNAs and common AD-associated gene products. Lithium changed expression of RNAs in both non-specific (inverse to sequence length) and specific (according to RNA type) fashions. The non-coding small nucleolar RNAs (snoRNAs) were subject to the greatest length-adjusted Li influence. When RNA length effects were taken into account, microRNAs as a group were significantly less likely to have had levels altered by Li treatment. Notably, several Li-influenced protein-coding RNAs were co-expressed or produced proteins that interacted with several common AD-associated genes and proteins. Lithium's modification of RNA levels depends on both RNA length and type. Li activity on snoRNA levels may pertain to bipolar disorders while Li modification of protein coding RNAs may be relevant to AD.

Topics: Alzheimer Disease; Cell Line, Tumor; Humans; Lithium Chloride; RNA; Transcriptome

Background Tauopathies, including Alzheimer's disease (AD), are multifactorial diseases with strong phenotypic and genetic heterogeneity. Recent evidence revealed that mechanisms of pathogenesis of early (hereditary) and late (sporadic) forms of AD are different. This is not properly reflected in current experimental models, especially when it comes to sporadic forms of AD. Here, we present novel seeding based model and explore its suitability for therapeutic intervention. New method We validate novel region specific approach to modelling Tau pathology reported by Koss and co-authors (2015). Wistar rats 3, 9 and 15 month-old were surgically prepared for hippocampal loading with pore-former polymeric 1,3-alkylpyridinium salts (Poly-APS) and recombinant human tau including pharmacological inhibition of phosphatase activity by okadaic acid co-administration. We explored whether tau seeding caused molecular and behavioural traits reminiscent of AD and explored their reversibility/prevention by administration of either memantine or lithium. Results The presented model emulates several changes observed in progressive dementia such as: heightened levels of tau and its hyperphosphorylation, changes in tau compartmentalization, breakdown of the cytoskeleton, cognitive impairments, and sensitivity for anti-dementia treatment. Comparison with existing methods Seeding has been achieved in transgenic mouse models, but this is the first rat model significantly mimicking cognitive and neuronal changes akin to tauopathies. Moreover, we have successfully included the factor age in our model and can show sensitivity to drug treatment. Conclusions These data validate a novel model of locally infused recombinant human Tau as an inducer of tauopathy in rats and holds the potential for development of novel therapies.

Topics: Alzheimer Disease; Animals; CA1 Region, Hippocampal; Disease Models, Animal; Lithium Chloride; Male; Memantine; Neurons; Neuroprotective Agents; Phosphorylation; Polymers; Pyridinium Compounds; Rats, Wistar; Recombinant Proteins; tau Proteins; Tauopathies

Topics: Alzheimer Disease; Animals; Antimanic Agents; Female; Humans; Learning; Lithium Chloride; Male; Memory; Mice; Mice, Inbred C57BL; Momordica charantia; Neuroprotective Agents; Ovariectomy; Random Allocation

Organotypic brain slice culture models provide an alternative to early stage in vivo studies as an integrated tissue system that can recapitulate key disease features, thereby providing an excellent platform for drug screening. We recently described a novel organotypic 3xTg-AD mouse brain slice culture model with key Alzheimer's disease-like changes. We now highlight the potential of this model for testing disease-modifying agents and show that results obtained following in vivo treatment are replicated in brain slice cultures from 3xTg-AD mice. Moreover, we describe novel effects of the amyloid-binding tetra (ethylene glycol) derivative of benzothiazole aniline, BTA-EG

Topics: Alzheimer Disease; Animals; Brain; Drug Evaluation, Preclinical; Glycogen Synthase Kinase 3; Humans; Lithium Chloride; Mice; Mice, Transgenic; Models, Biological; Oligopeptides; Organ Culture Techniques; Phosphorylation; Polyethylene Glycols; tau Proteins

In addition to extruding drugs from the brain, P-glycoprotein (P-gp) at the blood-brain barrier (BBB) facilitates the brain-to-blood clearance of beta-amyloid (Aβ) and is down-regulated in Alzheimer's disease. Studies suggest that the mood-stabilizing drug lithium exerts a protective effect against Alzheimer's disease. Although the mechanisms underlying this effect are not fully understood, evidence suggests that lithium chloride (LiCl) increases P-gp expression in vitro, albeit at concentrations substantially outside the therapeutic window. Therefore, we investigated the effects of pharmacologically-relevant concentrations of LiCl on P-gp expression using in vitro and in vivo approaches. Swiss outbred mice administered LiCl (300 mg/kg/day, 21 days) showed no change in brain microvascular P-gp protein expression. Furthermore, P-gp transcript and protein levels were unaltered by LiCl (1.25-5 mM, 24 h) in human immortalized brain endothelial cells, while both gene and protein expression were significantly enhanced by the P-gp up-regulator, SR12813 by 1.5-fold and 2.0-fold, respectively. P-gp efflux function was also unaffected by LiCl in vitro, by measuring accumulation of the fluorescent P-gp substrate rhodamine-123. This suggests therefore that LiCl is unlikely to affect the BBB efflux of Aβ or other P-gp substrates at pharmacologically-relevant concentrations, suggesting that the Aβ-lowering effects of LiCl are unrelated to elevated BBB P-gp expression.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; ATP Binding Cassette Transporter, Subfamily B; ATP Binding Cassette Transporter, Subfamily B, Member 1; Biological Transport; Blood-Brain Barrier; Blotting, Western; Brain; Cell Culture Techniques; Chlorates; Dose-Response Relationship, Drug; Down-Regulation; Endothelial Cells; Gene Expression; Humans; Lithium Chloride; Mice; Rhodamine 123; Transfection

Nrf2, a transcriptional activator of cell protection genes, is an attractive therapeutic target for the prevention of neurodegenerative diseases, including Alzheimer's disease (AD). Current Nrf2 activators, however, may exert toxicity and pathway over-activation can induce detrimental effects. An understanding of the mechanisms mediating Nrf2 inhibition in neurodegenerative conditions may therefore direct the design of drugs targeted for the prevention of these diseases with minimal side-effects. Our study provides the first in vivo evidence that specific inhibition of Keap1, a negative regulator of Nrf2, can prevent neuronal toxicity in response to the AD-initiating Aβ42 peptide, in correlation with Nrf2 activation. Comparatively, lithium, an inhibitor of the Nrf2 suppressor GSK-3, prevented Aβ42 toxicity by mechanisms independent of Nrf2. A new direct inhibitor of the Keap1-Nrf2 binding domain also prevented synaptotoxicity mediated by naturally-derived Aβ oligomers in mouse cortical neurons. Overall, our findings highlight Keap1 specifically as an efficient target for the re-activation of Nrf2 in AD, and support the further investigation of direct Keap1 inhibitors for the prevention of neurodegeneration in vivo.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Animals, Genetically Modified; Blotting, Western; Cell Line, Tumor; Cells, Cultured; Disease Models, Animal; Drosophila melanogaster; Drosophila Proteins; Gene Expression Profiling; Glycogen Synthase Kinase 3; Humans; Kelch-Like ECH-Associated Protein 1; Lithium Chloride; Longevity; Mice; Microscopy, Confocal; Neurons; NF-E2-Related Factor 2; Oleanolic Acid; Peptide Fragments; Protein Binding; Reverse Transcriptase Polymerase Chain Reaction; Thiadiazoles; Triazoles

Recent studies have suggested that G-protein-coupled receptor kinase 5 (GRK5) deficiency plays a significant role in the pathogenesis of early Alzheimer's disease. Mild soluble β-amyloid accumulation can result in reduced membrane (functional) and elevated cytosolic levels of GRK5. Dysfunction of GRK5 impairs the desensitization of presynaptic muscarinic 2 (M2) autoreceptors, which results in presynaptic M2 hyperactivity and inhibits acetylcholine (ACh) release. GRK dysfunction also promotes a deleterious cycle that further increases β-amyloid accumulation and exaggerates tau hyperphosphorylation in the hippocampus. However, the pathogenic effect of GRK5 dysfunction through targeting tau hyperphosphorylation remains unclear. Here we examined not only the reduced membrane (functional) and elevated cytosolic levels of GRK5 but also the increased levels of hyperphosphorylated tau in the hippocampi of aged APP(swe) mice (11 months of age). Moreover, western blotting analyses revealed the changes in the location of activity of both protein kinase C (PKC) and glycogen synthase kinase3β (GSK3β) in the hippocampus of aged APP(swe) mice in which GRK5 translocation occurred. Moreover, treatment with methoctramine, a selective M2 antagonist, partially corrected the difference between wild-type control mice and GRK5-dysfunctional APP (swe) mice in hippocampal ACh release, PKC and GSK3β activities, as well as tau hyperphosphorylation. In contrast, the GSK3β inhibitor lithium chloride significantly reduced tau hyperphosphorylation in GRK5-defective APP (swe) mice, but failed to enhance PKC activity and ACh release in the hippocampi of GRK5-defective APP (swe) mice. Taken together, these findings indicate that GRK5 dysfunction accelerated tau hyperphosphorylation in APP(swe) mice by activating GSK3β through impaired cholinergic activity.

Topics: Acetylcholine; Aging; Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Diamines; Disease Models, Animal; G-Protein-Coupled Receptor Kinase 5; Hippocampus; Humans; Lithium Chloride; Maze Learning; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Neurons; Parasympatholytics; Phosphorylation; tau Proteins

The glycogen synthase kinase-3β (GSK3β) pathway plays a central role in Alzheimer's disease (AD) and its deregulation accounts for many of the pathological hallmarks of AD. Lithium, which modulates GSK3β activity, has been shown to reduce amyloid production and tau phosphorylation in pre-pathological AD mouse models. In this study, we investigated the effects of chronic LiCl treatment in aged double transgenic mice (AβPPSwe/PS1A246E). We found that chronic lithium treatment decreased the γ-cleavage of amyloid-β protein precursor, further reduced amyloid-β production and senile plaque formation, accompanied by the improvement in spatial learning and memory abilities. Because autophagy may play an important role in the pathology of AD, we also assessed the autophagy activity and found that the chronic lithium treatment attenuated the autophagy activation in this AD mouse model. Our results suggest that prolonged lithium treatment, even during the later stages of AD, could be an effective therapeutics.

Topics: Aging; Alzheimer Disease; Amyloid beta-Peptides; Animals; Disease Models, Animal; Down-Regulation; Female; Glycogen Synthase Kinase 3; Lithium Chloride; Memory Disorders; Mice; Mice, Transgenic; Time Factors; Treatment Outcome

Glycogen synthase kinase-3beta (GSK3beta) is recognized as one of major kinases to phosphorylate tau in Alzheimer's disease (AD), thus lots of AD drug discoveries target GSK3beta. However, the inactive form of GSK3beta which is phosphorylated at serine-9 is increased in AD brains. This is also inconsistent with phosphorylation status of other GSK3beta substrates, such as beta-catenin and collapsin response mediator protein-2 (CRMP2) since their phosphorylation is all increased in AD brains. Thus, we addressed this paradoxical condition of AD in rat neurons treated with okadaic acid (OA) which inhibits protein phosphatase-2A (PP2A) and induces tau hyperphosphorylation and cell death. Interestingly, OA also induces phosphorylation of GSK3beta at serine-9 and other substrates including tau, beta-catenin and CRMP2 like in AD brains. In this context, we observed that GSK3beta inhibitors such as lithium chloride and 6-bromoindirubin-3'-monoxime (6-BIO) reversed those phosphorylation events and protected neurons. These data suggest that GSK3beta may still have its kinase activity despite increase of its phosphorylation at serine-9 in AD brains at least in PP2A-compromised conditions and that GSK3beta inhibitors could be a valuable drug candidate in AD.

Topics: Alzheimer Disease; Animals; Cells, Cultured; Disease Models, Animal; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Indoles; Lithium Chloride; Neurons; Okadaic Acid; Oximes; Phosphorylation; Protein Kinase Inhibitors; Protein Phosphatase 2; Rats; Serine

We have previously demonstrated that Leptin reduces extracellular amyloid beta (Abeta) protein both in vitro and in vivo, and intracellular tau phosphorylation in vitro. Further, we have shown that these effects are dependent on activation of AMP-activated protein kinase (AMPK) in vitro. Herein, we investigated downstream effectors of AMPK signaling directly linked to tau phosphorylation. One such target, of relevance to Alzheimer's disease (AD), may be GSK-3beta, which has been shown to be inactivated by Leptin. We therefore dissected the role of GSK-3beta in mediating Leptin's ability to reduce tau phosphorylation in neuronal cells. Our data suggest that Leptin regulates tau phosphorylation through a pathway involving both AMPK and GSK-3beta. This was based on the following: Leptin and the cell-permeable AMPK activator, 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR), reduced tau phosphorylation at AD-relevant sites similarly to the GSK-3beta inhibitor, lithium chloride (LiCl). Further, this reduction of tau phosphorylation was mimicked by the downregulation of GSK-3beta, achieved using siRNA technology and antagonized by the ectopic overexpression of GSK-3beta. These studies provide further insight into Leptin's mechanism of action in suppressing AD-related pathways.

Topics: Alzheimer Disease; Aminoimidazole Carboxamide; AMP-Activated Protein Kinases; Antimanic Agents; Brain; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Humans; Hypoglycemic Agents; Leptin; Lithium Chloride; Neurofibrillary Tangles; Neurons; Phosphorylation; Ribonucleotides; Signal Transduction; tau Proteins; Tumor Cells, Cultured

Calcium/calmodulin-dependent protein kinase IV (CaMKIV) plays a key role in the regulation of calcium-dependent gene expression. The expression of CaMKIV and the activation of CREB regulated genes are involved in memory and neuronal survival. We report here that: (a) a bioinformatic analysis of 15,476 promoters of the human genome predicted several Wnt target genes, being CaMKIV a very interesting candidate; (b) CaMKIV promoter contains TCF/LEF transcription motifs similar to those present in Wnt target genes; (c) biochemical studies indicate that lithium and the canonical ligand Wnt-3a induce CaMKIV mRNA and protein expression levels in rat hippocampal neurons as well as CaMKIV promoter activity; (d) treatment of hippocampal neurons with Wnt-3a increases the binding of beta-catenin to the CaMKIV promoter: (e) In vivo activation of the Wnt signaling improve spatial memory impairment and restores the expression of CaMKIV in a mice double transgenic model for Alzheimer's disease which shows decreased levels of the kinase. We conclude that CaMKIV is regulated by the Wnt signaling pathway and that its expression could play a role in the neuroprotective function of the Wnt signaling against the Alzheimer's amyloid peptide.

Topics: Alzheimer Disease; Animals; Behavior, Animal; beta Catenin; Calcium-Calmodulin-Dependent Protein Kinase Type 4; Cell Line; Computational Biology; Disease Models, Animal; Enhancer Elements, Genetic; Gene Expression; Hippocampus; Humans; Lithium Chloride; Mice; Mice, Inbred Strains; Mice, Transgenic; Neurons; Neuropsychological Tests; Promoter Regions, Genetic; Protein Binding; Rats; Rats, Inbred Strains; Signal Transduction; TCF Transcription Factors; Transfection; Wnt Proteins; Wnt3 Protein; Wnt3A Protein

The glycogen synthase kinase-3beta (GSK3beta) pathway plays an important role in mediating neuronal fate and synaptic plasticity. In Alzheimer's disease (AD), abnormal activation of this pathway might play an important role in neurodegeneration, and compounds such as lithium that modulate GSK3beta activity have been shown to reduce amyloid production and tau phosphorylation in amyloid precursor protein (APP) transgenic (tg) mice. However, it is unclear whether regulation of GSK3beta is neuroprotective in APP tg mice. In this context, the main objective of the present study was to determine whether pharmacological or genetic manipulations that block the GSK3beta pathway might ameliorate the neurodegenerative alterations in APP tg mice and to better understand the mechanisms involved. For this purpose, two sets of experiments were performed. First, tg mice expressing mutant human APP under the Thy1 promoter (hAPP tg) were treated with either lithium chloride or saline alone. Second, hAPP tg mice were crossed with GSK3beta tg mice, in which overexpression of this signaling molecule results in a dominant-negative (DN) effect with inhibition of activity. hAPP tg mice that were treated with lithium or that were crossed with DN-GSK3beta tg mice displayed improved performance in the water maze, preservation of the dendritic structure in the frontal cortex and hippocampus, and decreased tau phosphorylation. Moreover, reduced activation of GSK3beta was associated with decreased levels of APP phosphorylation that resulted in decreased amyloid-beta production. In conclusion, the present study showed that modulation of the GSK3beta signaling pathway might also have neuroprotective effects in tg mice by regulating APP maturation and processing and further supports the notion that GSK3beta might be a suitable target for the treatment of AD.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Brain; Dendrites; Enzyme Activation; Frontal Lobe; Genes, Dominant; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Hippocampus; Humans; Lithium Chloride; Maze Learning; Mice; Mice, Transgenic; Neuroprotective Agents; Phosphorylation; Signal Transduction; Swimming; tau Proteins

To investigate the alteration of beta-amyloid (Abeta) and glutamate transporter in the brain cortex of diabetes mellitus (DM) rats and the underlying mechanism.. The rats were randomly divided into control, DM, DM +NaCl, and DM +LiCl groups and diabetes was induced by streptozotocin. The activity of glycogen synthase kinase-3 (GSK-3) and the function of glutamate transporter were measured by 32P-labelling. The amount of Abeta was determined by enzyme-linked immunosorbentassay.. In DM group, the level of Abeta40 increased (P < 0.01), but the function of glutamate transporter was impaired (P < 0.05). The activity of GSK-3 was stimulated (P < 0.05). Compared with DM group, the level of Abeta40 was restored (P < 0.01), and the function of glutamate transporter was enhanced (P < 0.05) in LiCl treated group, accompanied by a decreased activity of GSK-3.. Overproduction of Abeta and impaired glutamate transporter exist in DM rats, and increase of GSK-3 may play a crucial role in this process.

Topics: Alzheimer Disease; Amino Acid Transport System X-AG; Amyloid beta-Peptides; Animals; Cerebral Cortex; Diabetes Mellitus, Experimental; Glycogen Synthase Kinase 3; Lithium Chloride; Male; Random Allocation; Rats; Rats, Sprague-Dawley

To examine the regulation of amyloid secretion in more detail, Abeta sandwich ELISAs with high sensitivity and specificity were developed. Using this technique, we measured Abeta secreted from COS7 cells transiently transfected with APP C100 in the presence of LiCl, a potent glycogen synthase kinase (GSK)-3beta inhibitor. We found that both Abetax-40 and Abetax-42 secretion were reduced by LiCl treatment in a dose-dependent manner. Diminished amyloid secretion was associated with GSK-3beta activity. These results suggest that GSK-3beta might function as a possible mediator for regulating both amyloid deposition and tau pathology in Alzheimer's disease (AD), and that lithium should be re-evaluated as a candidate reagent for preventing AD pathology.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; beta Catenin; Brain; Calcium-Calmodulin-Dependent Protein Kinases; COS Cells; Cytoskeletal Proteins; Dose-Response Relationship, Drug; Genetic Vectors; Glycogen Synthase; Glycogen Synthase Kinase 3; Glycogen Synthase Kinases; Lithium Chloride; Neurons; Peptide Fragments; Trans-Activators

In Alzheimer's disease, neurofibrillary degeneration results from the aggregation of abnormally phosphorylated Tau proteins into paired helical filaments. These Tau variants displayed specific epitopes that are immunoreactive with anti-phospho-Tau antibodies such as AT100. As shown in in vitro experiments, glycogen synthase kinase 3 beta (GSK3beta) and protein kinase A (PKA) may be key kinases in these phosphorylation events. In the present study, Tau was microinjected into Xenopus oocytes. Surprisingly, in this system, AT100 was generated without any GSK3beta and PKA contribution during the progesterone or insulin-induced maturation process. Our results demonstrate that a non-modified physiological process in a cell model can generate the most specific Alzheimer epitope of Tau pathology.

Topics: Alzheimer Disease; Animals; Calcium-Calmodulin-Dependent Protein Kinases; Cyclic AMP-Dependent Protein Kinases; Enzyme Inhibitors; Female; Glycogen Synthase Kinase 3; Glycogen Synthase Kinases; Humans; In Vitro Techniques; Lithium Chloride; Models, Biological; Oocytes; Phosphorylation; Protein Processing, Post-Translational; Recombinant Proteins; tau Proteins; Xenopus

Hyperphosphorylated tau is the major component of paired helical filaments in neurofibrillary tangles found in Alzheimer's disease (AD) brain. Starvation of adult mice induces tau hyperphosphorylation at many paired helical filaments sites and with a similar regional selectivity as those in AD, suggesting that a common mechanism may be mobilized. Here we investigated the mechanism of starvation-induced tau hyperphosphorylation in terms of tau kinases and Ser/Thr protein phosphatases (PP), and the results were compared with those reported in AD brain. During starvation, tau hyperphosphorylation at specific epitopes was accompanied by decreases in tau protein kinase I/glycogen synthase kinase 3 beta (TPKI/GSK3 beta), cyclin-dependent kinase 5 (cdk5), and PP2A activities toward tau. These results demonstrate that the activation of TPKI/GSK3 beta and cdk5 is not necessary to obtain hyperphosphorylated tau in vivo, and indicate that inhibition of PP2A is likely the dominant factor in inducing tau hyperphosphorylation in the starved mouse, overriding the inhibition of key tau kinases such as TPKI/GSK3 beta and cdk5. Furthermore, these data give strong support to the hypothesis that PP2A is important for the regulation of tau phosphorylation in the adult brain, and provide in vivo evidence in support of a central role of PP2A in tau hyperphosphorylation in AD.

Topics: Alzheimer Disease; Animals; Blotting, Western; Calcium-Calmodulin-Dependent Protein Kinases; Cyclin-Dependent Kinase 5; Cyclin-Dependent Kinases; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Enzyme Inhibitors; Food Deprivation; Glycogen Synthase Kinase 3; Hippocampus; Humans; Lithium Chloride; Male; Mice; Mice, Inbred C57BL; Models, Biological; Okadaic Acid; Phosphoprotein Phosphatases; Phosphorylation; Protein Phosphatase 2; Protein Serine-Threonine Kinases; Proteins; Time Factors; Up-Regulation

Presenilin 1 (PS1) is linked with Alzheimer's disease but exhibits functional roles regulating growth and development. For instance, PS1 binds to beta-catenin and modulates beta-catenin signaling. In the current study, we observed that knockout of PS1 inhibited beta-catenin-mediated transcription by 35%, as shown by a luciferase reporter driven by the hTcf-4 promoter. Overexpressing wild-type PS1 increased beta-catenin-mediated transcription by 37.5%, and overexpressing PS1 with mutations associated with Alzheimer's disease decreased beta-catenin-mediated transcription by 66%. To examine whether regulation of beta-catenin by PS1 requires phosphorylation by glycogen synthase kinase 3beta (GSK 3beta), we examined whether inhibiting GSK 3beta activity overcomes the inhibition of beta-catenin transcription induced by mutant PS1 constructs. Cells expressing wild-type or mutant PS1 were treated with LiCl, which inhibits GSK 3beta, or transfected with beta-catenin constructs that lack the GSK 3beta phosphorylation sites. Neither treatment overcame PS1-mediated inhibition of beta-catenin signaling, suggesting that regulation of beta-catenin by PS1 was not affected by the activity of GSK 3beta. To investigate how PS1 might regulate beta-catenin signaling, we determined whether PS1 interacts with other elements of the beta-catenin signaling cascade, such as the Tcf-4 transcription factor. Coimmunoprecipitation studies showed binding of PS1 and hTcf-4, and examining nuclear isolates indicated that nuclear hTcf-4 was decreased in cells expressing mutant PS1. These data show that PS1 interacts with multiple components of the beta-catenin signaling cascade and suggest that PS1 regulates beta-catenin in a manner independent of GSK 3beta activity.

Topics: Alzheimer Disease; Animals; beta Catenin; Calcium-Calmodulin-Dependent Protein Kinases; Cell Line; Cell Nucleus; Cytoskeletal Proteins; Glycogen Synthase Kinase 3; Glycogen Synthase Kinases; Humans; Immunoblotting; Immunohistochemistry; Lithium Chloride; Luciferases; Membrane Proteins; Mice; Mice, Knockout; Mutation; Plasmids; Precipitin Tests; Presenilin-1; Promoter Regions, Genetic; Protein Binding; Signal Transduction; TCF Transcription Factors; Trans-Activators; Transcription Factor 7-Like 2 Protein; Transcription Factors; Transcription, Genetic

1. The lipid bilayer technique was used to characterize the biophysical and pharmacological properties of several ion channels formed by incorporating amyloid beta protein fragment (AbetaP) 1-40 into lipid membranes. Based on the conductance, kinetics, selectivity, and pharmacological properties, the following AbetaP[1-40]-formed ion channels have been identified: (i) The AbetaP[1-40]-formed "bursting" fast cation channel was characterized by (a) a single channel conductance of 63 pS (250/50 mM KCl cis/trans) at +140 mV. 17 pS (250/50 mM KCl cis/trans) at -160 mV, and the nonlinear current-voltage relationship drawn to a third-order polynomial, (b) selectivity sequence PK > PNa > PLi = 1.0:0.60:0.47, (c) Po of 0.22 at 0 mV and 0.55 at +120 mV, and (d) Zn2+-induced reduction in current amplitude, a typical property of a slow block mechanism. (ii) The AbetaP[1-40]-formed "spiky" fast cation channel was characterized by (a) a similar kinetics to the "bursting" fast channel with exception for the absence of the long intraburst closures, (b) single channel conductance of 63 pS (250/50 KCl) at +140 mV 17 pS (250/50 KCl) at -160 mV, the current-voltage relationship nonlinear drawn to a third-order polynomial fit, and (c) selectivity sequence PRb > (iii) The AbetaP[1-40]-formed medium conductance channel was charcterized by (a) 275 pS (250/50 mM KCl cis/trans) at +140 mV and 19 pS (250/50 mM KCl cis/trans) at -160 mV and (b) inactivation at Vms more negative than -120 and more positive than +120 mV. (iv) The AbetaP[1-40]-formed inactivating large conductance channel was characterized by (a) fast and slow modes of opening to seven multilevel conductances ranging between 0-589 pS (in 250/50 mM KCI) at +140 mV and 0-704 pS (in 250/50 mM KCl) at -160 mV. (b) The fast mode which had a conductance of <250 pS was voltage dependent. The inactivation was described by a bell-shaped curve with a peak lag time of 7.2 s at +36 mV. The slow mode which had a conductance of >250 pS was also voltage dependent. The inactivation was described by a bell-shaped curve with a peak lag time of 7.0 s at -76 mV, (c) the value of PK/Pcholine for the fast mode was 3.9 and selectivity sequence PK > PCs > PNa > PLi = 1.0:0.94:0.87:0.59. The value of PK/Pcholine for the slow mode was 2.7 and selectivity sequence PK > FNa > PLi > PCs = 1.0:0.59:0.49:0.21, and (d) asymmetric blockade with 10 mM Zn2+-induced reduction in the large conductance state of the slow mode mediated via slow block mechani

Topics: Alzheimer Disease; Amyloid beta-Peptides; Cations; Cesium; Chlorides; Humans; Ion Channel Gating; Ion Channels; Kinetics; Lipid Bilayers; Lithium Chloride; Membrane Potentials; Patch-Clamp Techniques; Peptide Fragments; Potassium Chloride; Rubidium; Signal Transduction; Sodium Chloride; Structure-Activity Relationship; Zinc Compounds

Tau is a neuronal microtubule-associated protein found predominantly in axons. Hyperphosphorylation of tau reduces the stability of microtubules, which may be a pathogenic mechanism in Alzheimer's disease. To understand the different effects between tau and glycogen synthase kinase 3beta (GSK-3beta) phosphorylated tau on the organization and stability of microtubules, we performed transfection studies on 3T3 cells using EGFP-tau (Enhanced Green Fluorescence Protein-tau) and GSK-3beta to quantify the stability of microtubules. Laser confocal microscope observation revealed that thick and thin microtubule bundles could be induced by tau and GSK-3beta phosphorylated tau. The bundles appeared either to be relatively straight or to form a ring around the circumference of the cell. Both the thick and thin microtubule bundles were resistant to colchicine-induced dissociation, with thick bundles more resistant than thin bundles. The bundles induced by GSK-3beta phosphorylated tau were sensitive to colchicine, and could be reversed by the addition of LiCl, an inhibitor of GSK-3beta.

Topics: 3T3 Cells; Alzheimer Disease; Animals; Antimanic Agents; Axons; Brain; Calcium-Calmodulin-Dependent Protein Kinases; Colchicine; Fluorescent Antibody Technique; Glycogen Synthase Kinase 3; Glycogen Synthase Kinases; Gout Suppressants; Green Fluorescent Proteins; Indicators and Reagents; Lithium Chloride; Luminescent Proteins; Mice; Microtubules; Phosphorylation; tau Proteins; Transfection; Tubulin

Mutations in the presenilin (PSEN) genes are responsible for the majority of early-onset Alzheimer disease (AD) cases. PSEN1 is a component of a high molecular weight, endoplasmic reticulum, membrane-bound protein complex, including beta-catenin. Pathogenic PSEN1 mutations were demonstrated to have an effect on beta-catenin and glycogen synthase kinase-3beta(GSK-3beta), two members of the wingless Wnt pathway. The nuclear translocation and the stability of beta-catenin, and the interaction between GSK3beta and PSEN1 were influenced.. Stably transfected human embryonic kidney (HEK) 293 cells overexpressing wild-type (wt) and mutant (mt) PSEN1, treated with and without LiCl, were used to isolate cytoplasmic and nuclear fractions. By Western blot analysis, endogenous beta-catenin levels were examined. By analyzing cytosolic fractions of PSEN1, transfected and nontransfected HEK 293 cells, and total brain extracts of AD patients and controls, we evaluated the effect of PSEN1 overexpression on beta-catenin stability. Finally, we analyzed the effect of pathogenic PSEN1 mutations on the interaction between PSEN1 and GSK3beta by co-immunoprecipitation experiments.. We report reduced nuclear translocation of beta-catenin in cells stably expressing I143T, G384A, and T113-114ins PSEN1. The G384A PSEN1 mutation showed a similar pronounced effect on nuclear translocation of beta-catenin, as reported for processing of amyloid precursor protein (APP) into amyloid beta(Abeta). Overexpression of PSEN1 and the presence of pathogenic mutations in PSEN1 had no significant effect on the stability of beta-catenin. Nonspecific binding of overexpressed PSEN1 to endogenous GSK3beta was observed when GSK3beta was immunoprecipitated. Immunoprecipitation of PSEN1 in cells overexpressing PSEN1 and in native cells, however, did not result in co-immunoprecipitation of endogenous GSK3beta.. Our results further establish the nuclear translocation assay of beta-catenin as an adequate alternative for traditional Abeta measurement to evaluate the effect of PSEN1 mutations on biochemical processes. We detected no significant effect of overexpressed wt or mt PSEN1 on the stability of beta-catenin. Finally, co-immunoprecipitation between PSEN1 and GSK3beta was not observed in our experimental setup.

Topics: Active Transport, Cell Nucleus; Alzheimer Disease; beta Catenin; Blotting, Western; Brain Chemistry; Calcium-Calmodulin-Dependent Protein Kinases; Cell Fractionation; Cell Line; Cell Nucleus; Cytoskeletal Proteins; Glycogen Synthase Kinase 3; Glycogen Synthase Kinases; Humans; Lithium Chloride; Membrane Proteins; Microtubule-Associated Proteins; Mutagenesis, Site-Directed; Peptide Fragments; Precipitin Tests; Presenilin-1; Trans-Activators

Muscarinic agonists alter the metabolism of amyloid precursor protein, leading to an increase in alpha-secretase cleavage and a decreased production of amyloidogenic peptides; suggesting that these compounds might modify the Alzheimer's disease process. A second therapeutic target in AD is the accumulation of stably phosphorylated tau into neurofibrillary tangles; an early event correlating with cognitive impairment. Glycogen synthase kinase-3 (GSK-3beta) phosphorylates tau and is inhibited via protein kinase C (PKC). As certain muscarinic receptors are linked to PKC, we examined the effect of a range of agonists on GSK-3beta phosphorylation of tau. In neurons a nonspecific muscarinic agonist, carbachol, reduced tau phosphorylation. In nonneuronal cells expressing the ml receptor a range of ml agonists reduced transiently-expressed tau phosphorylation and altered its microtubulebinding properties. These findings link the two pathological process of AD-APP metabolism and tau phosphorylation - and suggest that muscarinic and other cholinergic compounds might have disease-modifying properties.

Topics: Acetylcholine; Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Binding Sites; Calcium-Calmodulin-Dependent Protein Kinases; Carbachol; Cells, Cultured; Fetus; Glycogen Synthase Kinase 3; Glycogen Synthase Kinases; Lithium Chloride; Microtubules; Muscarinic Agonists; Neurons; Phosphorylation; Pyridines; Rats; Rats, Sprague-Dawley; Receptors, Muscarinic; tau Proteins; Tetrazoles; Thiadiazoles

Lithium is one of the most widely used drugs for treating bipolar (manic-depressive) disorder. Despite its efficacy, the molecular mechanism underlying its action has not been elucidated. One recent study has proposed that lithium inhibits glycogen synthase kinase-3 and thereby affects multiple cellular functions. Because glycogen synthase kinase-3 regulates the phosphorylation of tau (microtubule-binding protein that forms paired helical filaments in neurons of the Alzheimer's disease brain), we hypothesized that lithium could affect tau phosphorylation by inhibiting glycogen synthase kinase-3. Using cultured human NT2N neurons, we demonstrate that lithium reduces the phosphorylation of tau, enhances the binding of tau to microtubules, and promotes microtubule assembly through direct and reversible inhibition of glycogen synthase kinase-3. These results provide new insights into how lithium mediates its effects in the central nervous system, and these findings could be exploited to develop a novel intervention for Alzheimer's disease.

Topics: Alanine; Alzheimer Disease; Amino Acid Sequence; Calcium-Calmodulin-Dependent Protein Kinases; Carcinoma, Embryonal; Cell Differentiation; Glycogen Synthase Kinase 3; Glycogen Synthase Kinases; Humans; Kinetics; Lithium Chloride; Microtubules; Mutagenesis, Site-Directed; Neurons; Phosphorylation; Point Mutation; Recombinant Proteins; Sequence Tagged Sites; Serine; tau Proteins; Transfection; Tretinoin; Tumor Cells, Cultured