Age-related GSK3ß overexpression drives podocyte senescence and glomerular aging.

As life expectancy continues to increase, clinicians are challenged by age-related renal impairment that involves podocyte senescence and glomerulosclerosis. There is now compelling evidence that lithium has a potent antiaging activity that ameliorates brain aging and increases longevity in Drosophila and Caenorhabditis elegans. As the major molecular target of lithium action and a multitasking protein kinase recently implicated in a variety of renal diseases, glycogen synthase kinase 3ß (GSK3ß) is overexpressed and hyperactive with age in glomerular podocytes, correlating with functional and histological signs of kidney aging. Moreover, podocyte-specific ablation of GSK3ß substantially attenuated podocyte senescence and glomerular aging in mice. Mechanistically, key mediators of senescence signaling, such as p16INK4A and p53, contain high numbers of GSK3ß consensus motifs, physically interact with GSK3ß, and act as its putative substrates. In addition, therapeutic targeting of GSK3ß by microdose lithium later in life reduced senescence signaling and delayed kidney aging in mice. Furthermore, in psychiatric patients, lithium carbonate therapy inhibited GSK3ß activity and mitigated senescence signaling in urinary exfoliated podocytes and was associated with preservation of kidney function. Thus, GSK3ß appears to play a key role in podocyte senescence by modulating senescence signaling and may be an actionable senostatic target to delay kidney aging.

Developmental Perfluorooctanesulfonic acid (PFOS) exposure as a potential risk factor for late-onset Alzheimer's disease in CD-1 mice and SH-SY5Y cells.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that accounts for approximately 60-80% of dementia cases worldwide and is characterized by an accumulation of extracellular senile plaques composed of ß-amyloid (Aß) peptide and intracellular neurofibrillary tangles (NFTs) containing hyperphosphorylated tau protein. Sporadic or late-onset AD (LOAD) represents 95 % of the AD cases and its etiology does not appear to follow Mendelian laws of inheritance, thus, implicating the role of epigenetic programming and environmental factors. Apolipoprotein allele 4 (ApoE4), the only established genetic risk factor for LOAD, is suggested to accelerate the pathogenesis of AD by increasing tau hyperphosphorylation, inhibiting the clearance of amyloid-ß (Aß), and promoting Aß aggregation. Perfluorooctanesulfonic acid (PFOS) is a persistent organic pollutant, with potential neurotoxic effects, that poses a major threat to the ecosystem and human health. By employing in vivo and in vitro models, the present study investigated PFOS as a potential risk factor for LOAD by assessing its impact on amyloidogenesis, tau pathology, and rodent behavior. Our behavioral analysis revealed that developmentally exposed male and female mice exhibited a strong trend of increased rearing and significantly increased distance traveled in the open field test. Biochemically, GSK3ß and total ApoE were increased following developmental exposure, in vivo. Furthermore, in vitro, low concentrations of PFOS elevated protein levels of APP, tau, and its site-specific phosphorylation. Differentiated SH-SY5Y cells exposed to a series of PFOS concentrations, also, had elevated protein expression of GSK3ß. These data suggest that total ApoE is inducible by environmental exposure to PFOS.

Lithium Chloride Protects against Sepsis-Induced Skeletal Muscle Atrophy and Cancer Cachexia.

Inflammation-mediated skeletal muscle wasting occurs in patients with sepsis and cancer cachexia. Both conditions severely affect patient morbidity and mortality. Lithium chloride has previously been shown to enhance myogenesis and prevent certain forms of muscular dystrophy. However, to our knowledge, the effect of lithium chloride treatment on sepsis-induced muscle atrophy and cancer cachexia has not yet been investigated. In this study, we aimed to examine the effects of lithium chloride using in vitro and in vivo models of cancer cachexia and sepsis. Lithium chloride prevented wasting in myotubes cultured with cancer cell-conditioned media, maintained the expression of the muscle fiber contractile protein, myosin heavy chain 2, and inhibited the upregulation of the E3 ubiquitin ligase, Atrogin-1. In addition, it inhibited the upregulation of inflammation-associated cytokines in macrophages treated with lipopolysaccharide. In the animal model of sepsis, lithium chloride treatment improved body weight, increased muscle mass, preserved the survival of larger fibers, and decreased the expression of muscle-wasting effector genes. In a model of cancer cachexia, lithium chloride increased muscle mass, enhanced muscle strength, and increased fiber cross-sectional area, with no significant effect on tumor mass. These results indicate that lithium chloride exerts therapeutic effects on inflammation-mediated skeletal muscle wasting, such as sepsis-induced muscle atrophy and cancer cachexia.

SCF-Slimb is critical for Glycogen synthase kinase-3ß-mediated suppression of TAF15-induced neurotoxicity in Drosophila.

Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disorder characterized pathologically by motor neuron degeneration and associated with aggregation of RNA-binding proteins. TATA-binding protein-associated factor 15 (TAF15) accumulates as cytoplasmic aggregates in neuronal cells, and clearance of these aggregates is considered a potential therapeutic strategy for ALS. However, the exact pathogenic mechanism of TAF15-induced neurotoxicity remains to be elucidated. Glycogen synthase kinase-3 (GSK-3) plays a critical role in the protection of ALS pathology. In the present study, we use a transgenic fly model over-expressing human TAF15 to study the protective effects of Shaggy/GSK3ß on TAF15-induced neuronal toxicity in Drosophila brain. Transgenic flies were examined for locomotor activity and lithium treatment. The expression level and solubility of TAF15 were assessed with western blotting, whereas immunohistochemistry was used to assess TAF15 aggregation in Drosophila brain. We have revealed that Shaggy/GSK3ß was abnormally activated in neurons of TAF15-expressing flies and its inhibition can suppress the defective phenotypes, thereby preventing retinal degeneration and locomotive activity caused by TAF15. We have also found that Shaggy/GSK3ß inhibition in neuronal cells leads to a reduction in TAF15 levels. Indeed, the F-box proteins Slimb and archipelago genetically interact with TAF15 and control TAF15 protein level in Drosophila. Importantly, SCFslimb is a critical regulator for Shaggy/GSK3ß-mediated suppression of TAF15-induced toxicity in Drosophila. The present study has provided an in vivo evidence supporting the molecular mechanism of GSK3ß inhibition for protection against TAF15-linked proteinopathies.

Fucoidan inhibits LPS-induced acute lung injury in mice through regulating GSK-3ß-Nrf2 signaling pathway.

The purpose of this study was to investigate the protective effects of fucoidan on Lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. The mice were divided into the control, LPS, and LPS + fucoidan (20, 40, or 80 mg/kg) groups. LPS was given by intracheal instillation and fucoidan was given 1 h before LPS treatment. Myeloperoxidase (MPO) activity, malondialdehyde (MDA), superoxide dismutase (SOD), reactive oxygen species (ROS), glutathione (GSH) contents, and inflammatory cytokine production were detected. The results showed that LPS-induced TNF-α, IL-1ß, and IL-6 production, lung wet/dry (W/D) ratio, ROS, MDA content, and MPO activity were suppressed by fucoidan. The levels of SOD and GSH were increased by fucoidan. Meanwhile, LPS-induced nuclear factor kappa-B (NF-κB) activation was dose-dependently attenuated by fucoidan. Furthermore, fucoidan increased the expression of nuclear factor erythroid-2 related factor 2 (Nrf2), Glycogen synthase kinase3ß (GSK-3ß), and heme oxygenase (HO-1). In vitro, the results demonstrated that fucoidan or GSK-3ß inhibitor significantly inhibited LPS-induced TNF-α production in A549 cells. And the inhibition of fucoidan on TNF-α production was blocked by Nrf2 siRNA. This study showed fucoidan protected mice against LPS-induced ALI through inhibiting inflammatory and oxidative responses via regulating GSK-3ß-Nrf2 signaling pathway.

Effects of Yixintai Pills on Myocardial Cell Apoptosis in Rats With Adriamycin-Induced Heart Failure.

OBJECTIVE: To study the effects of Yixintai pills on myocardial cell apoptosis in rats with adriamycin (ADR)-induced heart failure (HF) and the mechanism of action. METHODS: Sixty healthy male Wistar rats randomly were divided into Control, Model, Captopril, and Yixintai pill groups. A rat model of ADR-induced HF was constructed by intraperitoneal injection of ADR (2.5 mg/kg). The control group was given an equal volume of normal saline; the Yixintai pill and Captopril groups were given corresponding mediations (5 mg/kg) by lavage. After 4 weeks of treatment, fasting blood was collected to detect the contents of plasma rennin activity (PRA), angiotensin II (AngII), and aldosterone (ALD). B ultrasound was used to detect the heart structure, and the heart weight/body weight (HW/BW) ratio was calculated. The pathology of myocardial tissues was observed by HE staining. The apoptosis of myocardial cells was detected by TUNEL assay. The expression levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in serum were analyzed by ELISA, and the protein expression levels of protein kinase B (Akt), phosphorylated (p)-Akt, glycogen synthase kinase-3ß (GSK-3ß) and p-GSK-3ß in myocardial tissues were measured by Western blotting. RESULTS: Compared with the Control group, the PRA, AngII, ALD, left ventricular posterior wall thickness at end-systole (LVPWs), left ventricular posterior wall thickness at end-diastole (LVPWd), interventricular septal thickness at end-systole (IVSs), interventricular septal thickness at end-diastole (IVSd), HW/BW, TNF-α and IL-6 of model group increased significantly (P < .05). PRA, AngII, ALD, LVPWs, LVPWd, IVSs, IVSd, HW/BW, TNF-α and IL-6 of the Yixintai pill and Captopril groups were significantly lower than those of the Model group (P < .05). There were no significant differences in the indices between the Yixintai pill and Captopril groups (P > .05). In the Model group, lamellar necrosis, vacuolar degeneration, increased myocardial fibers and lamellar dissolution of myocardial cells were found in myocardial tissues. However, the myocardial cells of the Control group were neatly arranged and clearly structured, and only a few ones underwent fibrosis. There were mild myocardial fibrosis and vacuolar degeneration in the Yixintai pill and Captopril groups, and the degeneration and hyperplasia of myocardial fibers were obviously relieved. Compared with the Control group, the apoptosis index (AI) of the Model group increased significantly (P < .05). The AI values of the Yixintai pill and Captopril groups were significantly lower than those of the Model group (P < .05). Compared with the Control group, the expression levels of p-Akt and p-GSK-3ß in the Model group decreased significantly (P < .05). The expression levels of p-Akt and p-GSK-3ß in the Yixintai pill and Captopril groups were significantly higher than those of the Model group (P < .05), whereas the former 2 groups had similar results (P > 0.05). CONCLUSION: Yixintai pills may inhibit myocardial cell apoptosis and ventricular remodeling in rats by up-regulating PI3K/Akt/GSK-3ß signal, thus protecting the heart function.

Salidroside inhibits platelet function and thrombus formation through AKT/GSK3ß signaling pathway.

Salidroside is the main bioactive component in Rhodiola rosea and possesses multiple biological and pharmacological properties. However, whether salidroside affects platelet function remains unclear. Our study aims to investigate salidroside's effect on platelet function. Human or mouse platelets were treated with salidroside (0-20 µM) for 1 hour at 37°C. Platelet aggregation, granule secretion, and receptors expression were measured together with detection of platelet spreading and clot retraction. In addition, salidroside (20 mg/kg) was intraperitoneally injected into mice followed by measuring tail bleeding time, arterial and venous thrombosis. Salidroside inhibited thrombin- or CRP-induced platelet aggregation and ATP release and did not affect the expression of P-selectin, glycoprotein (GP) Ibα, GPVI and αIIbß3. Salidroside-treated platelets presented decreased spreading on fibrinogen or collagen and reduced clot retraction with decreased phosphorylation of c-Src, Syk and PLCγ2. Additionally, salidroside significantly impaired hemostasis, arterial and venous thrombus formation in mice. Moreover, in thrombin-stimulated platelets, salidroside inhibited phosphorylation of AKT (T308/S473) and GSK3ß (Ser9). Further, addition of GSK3ß inhibitor reversed the inhibitory effect of salidroside on platelet aggregation and clot retraction. In conclusion, salidroside inhibits platelet function and thrombosis via AKT/GSK3ß signaling, suggesting that salidroside may be a novel therapeutic drug for treating thrombotic or cardiovascular diseases.

A Small Compound Targeting Prohibitin with Potential Interest for Cognitive Deficit Rescue in Aging mice and Tau Pathology Treatment.

Neurodegenerative diseases, including Alzheimer's and Parkinson's disease, are characterized by increased protein aggregation in the brain, progressive neuronal loss, increased inflammation, and neurogenesis impairment. We analyzed the effects of a new purine derivative drug, PDD005, in attenuating mechanisms involved in the pathogenesis of neurodegenerative diseases, using both in vivo and in vitro models. We show that PDD005 is distributed to the brain and can rescue cognitive deficits associated with aging in mice. Treatment with PDD005 prevents impairment of neurogenesis by increasing sex-determining region Y-box 2, nestin, and also enhances synaptic function through upregulation of synaptophysin and postsynaptic density protein 95. PDD005 treatment also reduced neuro-inflammation by decreasing interleukin-1ß expression, activation of astrocytes, and microglia. We identified prohibitin as a potential target in mediating the therapeutic effects of PDD005 for the treatment of cognitive deficit in aging mice. Additionally, in the current study, glycogen synthase kinase appears to attenuate tau pathology.

Glycogen synthase kinase-3ß (GSK-3ß) of grass carp (Ctenopharyngodon idella): Synteny, structure, tissue distribution and expression in oleic acid (OA)-induced adipocytes and hepatocytes.

Glycogen synthase kinase-3ß (GSK-3ß) plays a crucial role in regulating lipid metabolism, endoplasmic reticulum (ER) stress and apoptosis in mammals, however, its gene structure and function is little known about in fish. Here, its two paralogs, grass carp (Ctenopharyngodon idella) GSK-3ß1 and GSK-3ß2 were isolated and characterized, encoding peptides of 421 and 457 amino acids, respectively. These two paralogs may have originated from the teleost-specific genome duplication (TSGD) event. Alignment of grass carp GSK-3ß deduced amino acid sequences with select teleost species showed that the protein is conserved. However, two paralogs of the GSK-3ß had great variation in gene structure: the GSK-3ß1 contained eleven exons while the GSK-3ß2 contained nine exons. The two paralogs were expressed in a wide range of tissues, GSK-3ß1 was most expressed in adipose tissue, GSK-3ß2 was most expressed in liver. In OA-induced adipocytes and hepatocytes, we found that GSK-3ß1 mRNA expression was significantly increased only in adipocytes, while the mRNA expression of GSK-3ß2 was dramatically increased both in adipocytes and hepatocytes. These results provide evidence that the GSK-3ß may participate in the process of lipid accumulation in OA-induced adipocytes and hepatocytes of grass carp.

Phytic acid attenuates upregulation of GSK-3ß and disturbance of synaptic vesicle recycling in MPTP-induced Parkinson's disease models.

Heightened activity of glycogen synthase kinase-3ß (GSK-3ß) is linked to the degeneration of dopaminergic neurons in Parkinson's disease (PD). Phytic acid (PA), a naturally occurring compound with potent antioxidant property, has been shown to confer neuroprotection on dopaminergic neurons in PD. However, the underlying mechanism remains unclear. In the present study, MPTP and MPP+ treatments were used to model PD in mice and SH-SY5Y cells, respectively. We observed reduced tissue dopamine, disrupted synaptic vesicle recycling, and defective neurotransmitter exocytosis. Furthermore, expression of GSK-3ß was upregulated while that of ß-catenin was downregulated, concentration of cytosolic calcium was increased, and expressions of two dopamine carriers, dopamine transporter (DAT) and vesicular monoamine transporter 2 (VMAT2) were decreased. PA treatment attenuated the MPTP-induced upregulation of GSK-3ß, increase in cytosolic calcium concentration, decreases in the levels of DAT, VMAT2, tissue dopamine, and synaptic vesicle recycling. Importantly, disturbances in synaptic vesicle recycling are thought to be early events in PD pathology. These findings suggest that PA is a promising therapeutic agent to treat early events in PD.

LncRNA BDNF-AS suppresses colorectal cancer cell proliferation and migration by epigenetically repressing GSK-3ß expression.

This study was designed to investigate the molecular mechanism and biological roles of long non-coding RNA (lncRNA) brain-derived neurotrophic factor antisense (BDNF-AS) in colorectal cancer (CRC). The quantitative real-time PCR (qRT-PCR) and western blotting were performed to detect the expressions of lncRNA BDNF-AS and glycogen synthase kinase-3ß (GSK-3ß) in human CRC tissues and cell lines. The cell proliferation, transwell migration, and invasion assays were carried out to evaluate the effect of lncRNA BDNF-AS on the growth of CRC cells. RNA pull-down and RNA immunoprecipitation (RIP) assays were conducted to confirm the interaction between lncRNA BDNF-AS and enhancer of Zeste Homologue 2 (EZH2). Chromatin immunoprecipitation (ChIP) assay was used to verify the enrichment of EZH2 and histone H3 lysine 27 trimethylation (H3K27me3) in the promoter region of GSK-3ß in CRC cells. LncRNA BDNF-AS expression was significantly decreased, while GSK-3ß was highly expressed in human CRC tissues and cell lines. Moreover, lncRNA BDNF-AS induced inhibition of proliferation, migration, and invasion of CRC cells via inhibiting GSK-3ß expression. Mechanistically, BDNF-AS led to GSK-3ß promoter silencing in CRC cells through recruitment of EZH2. In conclusion, lncRNA BDNF-AS functioned as an oncogene in CRC and shed new light on lncRNA-directed therapeutics in CRC. SIGNIFICANCE OF THE STUDY: LncRNA BDNF-AS is recently reported to be remarkably downregulated in a variety of tumours and served as a tumour suppressor. However, the functions and underlying mechanism of lncRNA BDNF-AS in CRC pathogenesis have not been reported yet. Our study is the first to demonstrate the effect of lncRNA BDNF-AS in CRC and revealed that lncRNA BDNF-AS expression is negatively correlated with the aggressive biological behaviour of CRC. Further investigation demonstrated that lncRNA BDNF-AS functioned as a tumour suppressor in CRC progression by suppressing GSK-3ß expression through binding to EZH2 and H3K27me3 with the GSK-3ß promoter, shedding light on the diagnosis and therapy for CRC.

Modulation by chronic antipsychotic administration of PKA- and GSK3ß-mediated pathways and the NMDA receptor in rat ventral midbrain.

RATIONALE: Antipsychotics exert therapeutic effects by modulating various cellular signalling pathways and several types of receptors, including PKA- and GSK3ß-mediated signalling pathways, and NMDA receptors. The ventral midbrain, mainly containing the ventral tegmental area (VTA) and substantia nigra (SN), are the nuclei with dopamine origins in the brain, which are also involved in the actions of antipsychotics. Whether antipsychotics can modulate these cellular pathways in the ventral midbrain is unknown. OBJECTIVE: This study aims to investigate the effects of antipsychotics, including aripiprazole (a dopamine D2 receptor (D2R) partial agonist), bifeprunox (a D2R partial agonist), and haloperidol (a D2R antagonist) on the PKA- and GSK3ß-mediated pathways and NMDA receptors in the ventral midbrain. METHODS: Male rats were orally administered aripiprazole (0.75 mg/kg, t.i.d. (ter in die)), bifeprunox (0.8 mg/kg, t.i.d.), haloperidol (0.1 mg/kg, t.i.d.) or vehicle for either 1 week or 10 weeks. The levels of PKA, p-PKA, Akt, p-Akt, GSK3ß, p-GSK3ß, Dvl-3, ß-catenin, and NMDA receptor subunits in the ventral midbrain were assessed by Western Blots. RESULTS: The results showed that chronic antipsychotic treatment with aripiprazole selectively increased PKA activity in the VTA. Additionally, all three drugs elevated the activity of the Akt-GSK3ß signalling pathway in a time-dependent manner, while only aripiprazole stimulated the Dvl-3-GSK3ß-ß-catenin signalling pathway in the SN. Furthermore, chronic administration with both aripiprazole and haloperidol decreased the expression of NMDA receptors. CONCLUSION: This study suggests that activating PKA- and GSK3ß-mediated pathways and downregulating NMDA receptor expression in the ventral midbrain might contribute to the clinical effects of antipsychotics.

OCT4B-190 protects against ischemic stroke by modulating GSK-3ß/HDAC6.

OCT4 is a key regulator in maintaining the pluripotency and self-renewal of embryonic stem cells (ESCs). Human OCT4 gene has three mRNA isoforms, termed OCT4A, OCT4B and OCT4B1. The 190-amino-acid protein isoform (OCT4B-190) is one of the major products of OCT4B mRNA, the biological function of which is still not well defined. Recent evidence suggests that OCT4B-190 may function in the cellular stress response. The glycogen synthase kinase-3ß (GSK-3ß) and histone deacetylase 6 (HDAC6) are also key stress modulators that play critical roles in the ischemic cascades of stroke. Hence, we here further investigated the effects of OCT4B-190 in the experimental stroke, and explored the underlying roles of GSK-3ß and HDAC6. We found that OCT4B-190 overexpression enhanced neuronal viability at 24 h after oxygen-glucose deprivation (OGD) treatment. Moreover, in male C57BL/6 mice subjected to transit middle cerebral artery occlusion (MCAO), OCT4B-190 overexpression reduced infarct volume and improved neurological function after stroke. Notably, we found spatio-temporal alterations of GSK-3ß and HDAC6 in the ischemic cortex and striatum, which were affected by adenovirus-mediated OCT4B-190 overexpression. OCT4B-190 demonstrated similar impacts on neuronal cultures in vitro, downregulating OGD-induced GSK-3ß activity and HDAC6 expression. In addition, we found that GSK-3ß and HDAC6 were co-expressed in the cytoplasm of neurons, and OCT4B-190 had an effect on interactions between GSK-3ß and HDAC6 in neuronal cultures subjected to OGD treatment. These findings suggest that OCT4B-190 exerts neuroprotection in the experimental stroke potentially by regulating actions of GSK-3ß and HDAC6 simultaneously, which may be an attractive therapeutic strategy for ischemic stroke.

GSK3ß overexpression driven by GFAP promoter improves rotarod performance.

We have studied the consequences of in vivo GSK3ß overexpression in the cerebellum using transgenic mice with conditional expression where the transactivator tTA protein expression is driven by GFAP promoter. We demonstrate an increase in GSK3ß in Bergmann cells. To study cerebellar dysfunctions and evaluate motor coordination we analysed the latency to fall in the accelerating rotarod test. GSK3ß transgenic mice performed significantly better than wild-type mice and transgene shutdown with doxycycline normalizes the values in latency to fall in rotarod test. We had previously demonstrated using the same transgenic model, that overexpression of GSK3ß in the hippocampus results in an increase in neural precursor cells. However, we did not observe that increase in the number of Sox2+ cells in the cerebellum. All the same, we observed an increase in cerebellar glutamate transporters GLT1 and GLAST. These data show that GSK3ß can be a crucial kinase in cerebellum and especially in Bergmann glial cells.

Igalan induces detoxifying enzymes mediated by the Nrf2 pathway in HepG2 cells.

Igalan is one of the sesquiterpene lactones found in Inula helenium L., which is used as the traditional medicine to treat inflammatory diseases. However, the pharmacological effects of igalan have not been characterized. In this study, we isolated igalan from I. helenium L. and evaluated the effects of igalan on signaling pathways and expression of target genes in HepG2 cells. Igalan activated the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway by increasing the inactive form of GSK3ß, the phosphorylated form of AKT, and the nuclear accumulation of Nrf2. Thus, target genes of Nrf2 such as HO-1 and NQO1 increased in HepG2 cells. Moreover, igalan inhibited the tumor necrosis factor-α (TNF-α)-induced nuclear factor-κB activation and suppressed the expression of its target genes, including TNF-α, interleukin (IL)-6, and IL-8 in HepG2 cells. Our results indicate the potential of igalan as an activator of cellular defense mechanisms and a detoxifying agent.

miR-219-5p inhibits tau phosphorylation by targeting TTBK1 and GSK-3ß in Alzheimer's disease.

As the most common neurodegenerative disease, Alzheimer's disease (AD) is characterized by memory, perception, and behavioral damage, which may ultimately lead to emotional fluctuation and even lethal delirium. Increasing studies indicate that microRNAs (miRNAs) are associated with pathological features of AD. However, the role of miR-219-5p in AD progression is still unclear. In this study, the functions of miR-219-5p were analyzed in vitro and in vivo. miR-219-5p was notably overexpressed in brain tissues of patients with AD. The overexpression of miR-219-5p activated the phosphorylation of Tau-Ser198, Tau-Ser199, Tau-Ser201, and Tau-Ser422. We further showed that miR-219-5p could mediate a decrease in the protein levels of tau-tubulin kinase 1 (TTBK1) and glycogen synthase kinase 3ß (GSK-3ß) by directly binding to their 3'-untranslated region, thereby promoting the phosphorylation of tau in SH-SY5Y Cells. Rescue experiments further revealed that the phosphorylation of tau-mediated by miR-219-5p was dependent on the inhibition of TTBK1 and GSK-3ß. Moreover, suppressing the expression of both TTBK1 and GSK-3ß using miR-219-5p remarkably rescued AD-like symptoms in amyloid precursor protein/presenilin 1 mice. Our findings indicate that the upregulation of TTBK1 and GSK-3ß mediated by the loss of miR-219-5p is a possible mechanism that contributes to tau phosphorylation and AD progression.

Effects and mechanism of epigallocatechin-3-gallate on apoptosis and mTOR/AKT/GSK-3ß pathway in substantia nigra neurons in Parkinson rats.

The aim of this study is to investigate the protective effect of epigallocatechin-3-gallate (EGCG) on apoptosis and mTOR/AKT/GSK-3ß pathway in substantia nigra neurons in 6-dopamine-induced Parkinson rats. A total of 30 healthy male SD rats were randomly divided into control group, the Parkinson model group, and Parkinson model+EGCG treatment group. The model and EGCG groups were injected into the right striatum with 6-OHDA to establish the Parkinson model, and the control group was injected with saline only. The EGCG group was intragastrically administered with EGCG 50 mg/kg daily for 4 weeks. The rats' turns, speed, and left forelimb usage; neuron apoptosis by TUNEL; and the α-synuclein protein expression in substantia nigra by immunohistochemical staining were studied. Western blotting was used to detect the relative protein (mTOR, AKT and GSK-3ß) expressions. Compared with the model group, the EGCG group significantly reduced the rotation speed; increased the left forelimb usage (P<0.01); reduced the neuron apoptosis (P<0.01); decreased α-synuclein expression (P<0.01); and decreased the mTOR, AKT, and GSK-3ß protein expressions (P<0.01). EGCG can reduce neuron cell apoptosis in substantia nigra neurons in 6-OHDA-induced Parkinson rats. The mechanism might be related to mTOR/AKT/GSK-3ß activation.

Cognitive, behavioral and metabolic effects of oral galactose treatment in the transgenic Tg2576 mice.

Alzheimer's disease (AD) is the most common neurodegenerative disorder associated with insulin resistance and glucose hypometabolism in the brain. Oral administration of galactose, a nutrient that provides an alternative source of energy, prevents and ameliorates early cognitive impairment in a streptozotocin-induced model (STZ-icv) of the sporadic AD (sAD). Here we explored the influence of 2-month oral galactose treatment (200 mg/kg/day) in the familial AD (fAD) by using 5- (5M) and 10- (10M) month-old transgenic Tg2576 mice mimicking the presymptomatic and the mild stage of fAD, and compared it to that observed in 7-month old STZ-icv rats mimicking mild-to-moderate sAD. Cognitive and behavioral performance was tested by Morris Water Maze, Open Field and Elevated Plus Maze tests, and metabolic status by intraperitoneal glucose tolerance test and fluorodeoxyglucose Positron-Emission Tomography scan. The level of insulin, glucagon-like peptide-1 (GLP-1) and soluble amyloid ß1-42 (sAß1-42) was measured by ELISA and the protein expression of insulin receptor (IR), glycogen synthase kinase-3ß (GSK-3ß), and pre-/post-synaptic markers by Western blot analysis. Although galactose normalized alterations in cerebral glucose metabolism in all Tg2576 mice (5M+2M; 10M+2M) and STZ-icv rats, it did not improve cognitive impairment in either model. Improvement of reduced grooming behavior and normalization in reduced plasma insulin levels were seen only in 5M+2M Tg2576 mice while in 10M+2M Tg2576 mice oral galactose induced metabolic exacerbation at the level of plasma insulin, GLP-1 homeostasis and glucose intolerance, and additionally increased hippocampal sAß1-42 level, decreased IR expression and increased GSK-3ß activity. The results indicate that therapeutic potential of oral galactose seems to depend on the stage and the type/model of AD and to differ in the absence and the presence of AD-like pathology.

Glycogen synthase kinase 3 beta regulates ethanol consumption and is a risk factor for alcohol dependence.

Understanding how ethanol actions on brain signal transduction and gene expression lead to excessive consumption and addiction could identify new treatments for alcohol dependence. We previously identified glycogen synthase kinase 3-beta (Gsk3b) as a member of a highly ethanol-responsive gene network in mouse medial prefrontal cortex (mPFC). Gsk3b has been implicated in dendritic function, synaptic plasticity and behavioral responses to other drugs of abuse. Here, we investigate Gsk3b in rodent models of ethanol consumption and as a risk factor for human alcohol dependence. Stereotactic viral vector gene delivery overexpression of Gsk3b in mouse mPFC increased 2-bottle choice ethanol consumption, which was blocked by lithium, a known GSK3B inhibitor. Further, Gsk3b overexpression increased anxiety-like behavior following abstinence from ethanol. Protein or mRNA expression studies following Gsk3b over-expression identified synaptojanin 2, brain-derived neurotrophic factor and the neuropeptide Y Y5 receptor as potential downstream factors altering ethanol behaviors. Rat operant studies showed that selective pharmacologic inhibition of GSK3B with TDZD-8 dose-dependently decreased motivation to self-administer ethanol and sucrose and selectively blocked ethanol relapse-like behavior. In set-based and gene-wise genetic association analysis, a GSK3b-centric gene expression network had significant genetic associations, at a gene and network level, with risk for alcohol dependence in humans. These mutually reinforcing cross-species findings implicate GSK3B in neurobiological mechanisms controlling ethanol consumption, and as both a potential risk factor and therapeutic target for alcohol dependence.

Glycogen synthase kinase-3ß inhibition enhances myelination in preterm newborns with intraventricular hemorrhage, but not recombinant Wnt3A.

Intraventricular hemorrhage (IVH) in preterm infants results in reduced proliferation and maturation of oligodendrocyte progenitor cells (OPCs), and survivors exhibit reduced myelination and neurological deficits. Wnt signaling regulates OPC maturation and myelination in a context dependent manner. Herein, we hypothesized that the occurrence of IVH would downregulate Wnt signaling, and that activating Wnt signaling by GSK-3ß inhibition or Wnt3A recombinant human protein (rh-Wnt3A) treatment might promote maturation of OPCs, myelination of the white matter, and neurological recovery in premature rabbits with IVH. These hypotheses were tested in autopsy samples from preterm infants and in a rabbit model of IVH. Induction of IVH reduced expressions of activated ß-catenin, TCF-4, and Axin2 transcription factors in preterm newborns. Both AR-A014418 (ARA) and Wnt-3A treatment activated Wnt signaling. GSK-3ß inhibition by intramuscular ARA treatment accelerated maturation of OPCs, myelination, and neurological recovery in preterm rabbits with IVH compared to vehicle controls. In contrast, intracerebroventricular rh-Wnt3A treatment failed to enhance myelination and neurological function in rabbits with IVH. ARA treatment reduced microglia infiltration and IL1ß expression in rabbits with IVH relative to controls, whereas Wnt3A treatment elevated TNFα, IL1ß, and IL6 expression without affecting microglia density. GSK-3ß inhibition downregulated, while rh-Wnt3A treatment upregulated Notch signaling; and none of the two treatments affected the Sonic-Hedgehog pathway. The administration of ARA or rh-Wnt3A did not affect gliosis. The data suggest that GSK-3ß inhibition promoted myelination by suppressing inflammation and Notch signaling; and Wnt3A treatment failed to enhance myelination because of its pro-inflammatory activity and synergy with Notch signaling. GSK-3ß inhibitors might improve the neurological outcome of preterm infants with IVH.