Neurofibrillary tangle (NFT) is a characteristic hallmark of Alzheimer's disease. GSK3beta has been reported to play a major role in the NFT formation of tau. Dysfunction of autophagy might facilitate the aggregate formation of tau. The present study examined the role of GSK3beta-mediated phosphorylation of tau species on their autophagic degradation. We transfected wild type tau (T4), caspase-3-cleaved tau at Asp421 (T4C3), or pseudophosphorylated tau at Ser396/Ser404 (T4-2EC) in the presence of active or enzyme-inactive GSK3beta. Trehalose and 3-methyladenine (3-MA) were used to enhance or inhibit autophagic activity, respectively. All tau species showed increased accumulation with 3-MA treatment whereas reduced with trehalose, indicating that tau undergoes autophagic degradation. However, T4C3 and T4-2EC showed abundant formation of oligomers than T4. Active GSK3beta in the presence of 3-MA resulted in significantly increased formation of insoluble tau aggregates. These results indicate that GSK3beta-mediated phosphorylation and compromised autophagic activity significantly contribute to tau aggregation.
Adenine ; Alzheimer Disease ; Autophagy ; Glycogen ; Glycogen Synthase ; Glycogen Synthase Kinase 3 ; Glycogen Synthase Kinases ; Neurofibrillary Tangles ; Phosphorylation ; Trehalose

Little is known about the effects of chronic alcohol intake on the outcome of acute kidney injury (AKI). Hence, we examined the effects of chronic alcohol intake on the development of renal fibrosis following AKI in an animal model of bilateral renal ischemia–reperfusion (IR) injury. We first found that chronic alcohol exposure exacerbated bilateral IR-induced renal fibrosis and renal function impairment. This phenomenon was associated with increased bilateral IR-induced extracellular matrix deposition and an increased myofibroblast population as well as increased bilateral IR-induced expression of fibrosis-related genes in the kidneys. To explore the mechanisms underlying this phenomenon, we showed that chronic alcohol exposure enhanced β-arrestin 2 (Arrb2) expression and Akt and glycogen synthase kinase-3 (GSK3)β activation in the kidneys. Importantly, pharmacological GSK3 inhibition alleviated bilateral IR-induced renal fibrosis and renal function impairment. Furthermore, we demonstrated that Arrb2(−/−) mice exhibited resistance to IR-induced renal fibrosis and renal function impairment following chronic alcohol exposure, and these effects were associated with attenuated GSK3β activation in the kidneys. Taken together, our results suggest that chronic alcohol exposure may potentiate AKI via β-arrestin 2/Akt/GSK3β-mediated signaling in the kidney.
Acute Kidney Injury* ; Animals ; Extracellular Matrix ; Fibrosis ; Glycogen Synthase Kinase 3* ; Glycogen Synthase Kinases* ; Glycogen Synthase* ; Glycogen* ; Kidney ; Mice* ; Models, Animal ; Myofibroblasts

OBJECTIVE: Glycogen synthase kinase 3β (GSK3β) is a pluripotent protein kinase involved in the development of cancers through regulation of numerous oncogenic molecules. Cyclin D1, an important regulator of G1 to S phase transition in various cells, is one of target proteins that GSK3β regulate. Our objective was to assess the expression of GSK3β and cyclin D1 in cervical neoplasm of different histologic grades and to identify their correlation in cervical carcinogenesis. METHODS: Immunohistochemical analysis of GSK3β and cyclin D1 was performed in a total of 137 patients with 12 normal, 62 cervical intraepithelial neoplasia (CIN) (31 CIN1 and 31 CIN3) and 63 invasive cancers including 56 squamous cell carcinomas and 7 adenocarcinomas. RESULTS: The expression of GSK3β increased in parallel with the lesion grade, while that of cyclin D1 decreased with severity of the lesion (P<0.001). There was a significant inverse correlation between GSK3β and cyclin D1 expression in overall cervical neoplasia (Φ=-0.413, P<0.001). GSK3β expression was higher in squamous cell carcinoma than in adenocarcinoma (P=0.049). CONCLUSION: These results suggest that the expressional increase in GSK3β plays a role in cervical carcinogenesis and has inverse correlation with cyclin D1 expression in this process. In addition, GSK3β expression appears to be associated with the histologic type of cervical cancer, especially squamous cell carcinoma.
Adenocarcinoma ; Carcinogenesis* ; Carcinoma, Squamous Cell ; Cervical Intraepithelial Neoplasia ; Cyclin D1* ; Cyclins* ; Glycogen Synthase Kinases* ; Glycogen Synthase* ; Glycogen* ; Humans ; Immunohistochemistry ; Protein Kinases ; S Phase ; Uterine Cervical Neoplasms

In the present study, we investigated influences of glycogen synthase kinase (GSK) 3beta on the development and/or progression of amyotrophic lateral sclerosis (ALS). We used transgenic mice expressing a human Cu/Zn superoxide dismutase mutant (SOD1G93A) as an in vivo model of ALS and examined expressional changes of GSK3beta immunohistochemically in the spinal cord, brain stem and cerebellum. With these experiments we demonstrate that the neurons in these regions of symptomatic SOD1G93A transgenic mice showed increased GSK3beta immunoreactivities compared with wild-type SOD1 transgenic mice. In contrast to symptomatic SOD1G93A transgenic mice, few GSK3beta immunoreactivity changes were detected in 8w- and 13w-old presymptomatic SOD1G93A transgenic mice. These data suggest the possibility that GSK3 functions as a modulating factor of apoptosis-related alterations in ALS and that GSK3beta exert differential functions in the development and/or progression of ALS. But the exact functional significances of these changes require further elucidation.
Amyotrophic Lateral Sclerosis ; Animals ; Brain Stem ; Central Nervous System* ; Cerebellum ; Glycogen Synthase Kinases* ; Glycogen Synthase* ; Glycogen* ; Humans ; Mice ; Mice, Transgenic* ; Neurons ; Spinal Cord ; Superoxide Dismutase

Glycogen synthase kinase (GSK)-3β and related enzymes are associated with various forms of neuroinflammation, including spinal cord injury (SCI). Our aim was to evaluate whether lithium, a non-selective inhibitor of GSK-3β, ameliorated SCI progression, and also to analyze whether lithium affected the expression levels of two representative GSK-3β–associated molecules, nuclear factor erythroid 2-related factor-2 (Nrf-2) and heme oxygenase-1 (HO-1) (a target gene of Nrf-2). Intraperitoneal lithium chloride (80 mg/kg/day for 3 days) significantly improved locomotor function at 8 days post-injury (DPI); this was maintained until 14 DPI (P<0.05). Western blotting showed significantly increased phosphorylation of GSK-3β (Ser9), Nrf-2, and the Nrf-2 target HO-1 in the spinal cords of lithium-treated animals. Fewer neuropathological changes (e.g., hemorrhage, inflammatory cell infiltration, and tissue loss) were observed in the spinal cords of the lithium-treated group compared with the vehicle-treated group. Microglial activation (evaluated by measuring the immunoreactivity of ionized calcium-binding protein-1) was also significantly reduced in the lithium-treated group. These findings suggest that GSK-3β becomes activated after SCI, and that a non-specific enzyme inhibitor, lithium, ameliorates rat SCI by increasing phosphorylation of GSK-3β and the associated molecules Nrf-2 and HO-1.
Animals ; Blotting, Western ; Glycogen Synthase Kinases ; Glycogen Synthase* ; Glycogen* ; Heme Oxygenase-1* ; Heme* ; Hemorrhage ; Lithium Chloride ; Lithium* ; Phosphorylation ; Rats* ; Spinal Cord Injuries* ; Spinal Cord*

BACKGROUND: Glycogen synthase kinase 3beta (GSK3beta) is a ubiquitous serine/threonine kinase that is regulated by serine phosphorylation at 9. Recent studies have reported the beneficial effects of a number of the pharmacological GSK3beta inhibitors in rodent models of septic shock. Since most of the GSK3beta inhibitors are targeted at the ATP-binding site, which is highly conserved among diverse protein kinases, the development of novel non-ATP competitive GSK3beta inhibitors is needed. METHODS: Based on the unique phosphorylation motif of GSK3beta, we designed and generated a novel class of GSK3beta inhibitor (GSK3i) peptides. In addition, we investigated the effects of a GSK3i peptide on lipopolysaccharide (LPS)-stimulated cytokine production and septic shock. Mice were intraperitoneally injected with GSK3i peptide and monitored over a 7-day period for survival. RESULTS: We first demonstrate its effects on LPS-stimulated pro-inflammatory cytokine production including interleukin (IL)-6 and IL-12p40. LPS-induced IL-6 and IL-12p40 production in macrophages was suppressed when macrophages were treated with the GSKi peptide. Administration of the GSK3i peptide potently suppressed LPS-mediated endotoxin shock. CONCLUSION: Collectively, we present a rational strategy for the development of a therapeutic GSK3i peptide. This peptide may serve as a novel template for the design of non-ATP competitive GSK3 inhibitors.
Animals ; Cytokines ; Glycogen Synthase Kinase 3 ; Glycogen Synthase Kinases ; Interleukin-12 Subunit p40 ; Interleukin-6 ; Interleukins ; Macrophages ; Mice ; Peptides ; Phosphorylation ; Phosphotransferases ; Protein Kinases ; Rodentia ; Serine ; Shock ; Shock, Septic

OBJECTIVES: This study aimed to demonstrate the activities and phosphorylation changes induced by acute ethanol treatment and withdrawal conditions in the intracellular signal transduction molecules [such as extracellular signal-regulated kinase (ERK), glycogen synthase kinase 3beta (GSK3beta), and Akt] of the SH-SY5Y neuroblastoma cell line. METHODS: The acute treatment exposed SH-SY5Y cells to 100 mM ethanol, and we took samples 30 minutes, 60 minutes, and 24 hours after initiating this treatment. After 24 hours' continuous ethanol treatment, we initiated ethanol withdrawal, taking samples at 30 minutes and 60 minutes. We assayed the kinase phosphorylations via an immunoblot analysis using phosphorspecific antibodies, quantified by optical densitometry. RESULTS: Ethanol treatment induced a transient increase in phosphorylation of GSK3beta and Akt at 30 minutes but failed to change the phosphorylation level of ERK. Ethanol withdrawal induced a transient ERK phosphorylation increase at 30 minutes, but it had no effect on the phosphorylation of GSK3beta or Akt. CONCLUSION: The results indicate that the ethanol-induced cellular response includes the ERK, GSK3beta, and Akt systems. In particular, the ERK pathway may play a role in the acute withdrawal response. This also suggests that a relatively short exposure to ethanol, such as the 24-hour exposure in this study, can induce functional adaptation within a cell.
Antibodies ; Cell Line ; Densitometry ; Ethanol ; Glycogen Synthase Kinase 3 ; Glycogen Synthase Kinases ; Humans ; MAP Kinase Signaling System ; Neuroblastoma ; Phosphorylation ; Phosphotransferases ; Signal Transduction

Proto-Oncogene Proteins c-akt/metabolism* ; Butyrates ; Ligands ; Glucose ; Receptors, G-Protein-Coupled/metabolism* ; Glycogen Synthase Kinases/metabolism* ; Glycogen Synthase Kinase 3 beta ; Phosphorylation

OBJECTIVETo research the effects of glycogen synthase kinase (GSK3β) overexpression and GSK3β inhibitor SB-216763 on the proliferation of hepatic oval cells in rats and its regulatory mechanisms by Wnt signaling pathway.

METHODSThe hepatic oval cells WBF-344 were divided into the blank control group, GSK3β over-expression group, DMSO control group and GSK3β inhibitor groups, while the inhibitor groups set up three concentration gradients, that was 1, 5, 10 µmol/L. Using the GSK3β over-expression lentivirus, which had been identified correctly, and SB-216763 dealt with the cells WBF-344. The cells morphology of each group was observed under the phase contrast inverted microscope, and the expression of fluorescence in the lentivirus-transfected group was observed under the fluorescent microscope. The proliferation of each group cells was tested by CCK8 kits. The cells' apoptosis was detected by AnnexinV-FITC/PI kits. The expression of GSK3β, β-catenin and cyclin D1 were detected by Western blot.

RESULTSThe cells of GSK3β over-expression group were fewer and obvious aging. However, in each inhibitor added group, the cells' division and proliferation was vigorous, and the condition was good. Moreover, the cells' proliferation was getting stronger with the concentration of SB-216763 increasing. A large number of green fluorescence was expressed in the lentivirus-transfected cells. The cells' proliferation in GSK3β over-expression group restrained (t = 7.178, P < 0.01, as compared with control), while the cells' proliferation was vigorous in inhibitor groups (F = 45.030, P < 0.01, as compared with control). Flow Cytometry showed that the cells apoptosis was significant in GSK3β over-expression group. Western blot showed that the expression of GSK3β was increased, while the expression of β-catenin and cyclin D1 was decreased in the over-expression group. The expression of GSK3β had no significant difference among the control group and inhibitor groups. However, the expression of β-catenin and cyclin D1 was significantly increased with the concentration of SB-216763 increasing.

CONCLUSIONSThe overexpression of GSK3β can inhibit the Wnt signaling pathway, thus restrain the cells' proliferation and promotes apoptosis. SB-216763 can activate the Wnt pathway, thus promotes cells' proliferation.

Animals ; Cell Line ; Cell Proliferation ; drug effects ; Cyclin D1 ; metabolism ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; Glycogen Synthase Kinases ; metabolism ; Hepatocytes ; drug effects ; Indoles ; pharmacology ; Male ; Maleimides ; pharmacology ; Rats ; Transfection ; Wnt Signaling Pathway ; beta Catenin ; metabolism

Although benfotiamine has various beneficial anti-diabetic effects, the detailed mechanisms underlying the impact of this compound on the insulin signaling pathway are still unclear. In the present study, we evaluated the effects of benfotiamine on the hepatic insulin signaling pathway in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, which are a type 2 diabetes mellitus model. OLETF rats treated with benfotiamine showed decreased body weight gain and reduced adipose tissue weight. In addition, blood glucose levels were lower in OLETF rats treated with benfotiamine. Following treatment with benfotiamine, the levels of Akt phosphorylation (S473/T308) in the OLETF groups increased significantly compared to the OLETF control group so that they were almost identical to the levels observed in the control group. Moreover, benfotiamine restored the phosphorylation levels of both glycogen synthase kinase (GSK)-3alpha/beta (S21, S9) and glycogen synthase (GS; S641) in OLETF rats to nearly the same levels observed in the control group. Overall, these results suggest that benfotiamine can potentially attenuate type 2 diabetes mellitus in OLETF rats by restoring insulin sensitivity through upregulation of Akt phosphorylation and activation of two downstream signaling molecules, GSK-3alpha/beta and GS, thereby reducing blood glucose levels through glycogen synthesis.
Adipose Tissue ; Animals* ; Blood Glucose ; Body Weight ; Diabetes Mellitus, Type 2* ; Glycogen ; Glycogen Synthase ; Glycogen Synthase Kinases ; Insulin ; Insulin Resistance ; Models, Animal* ; Phosphorylation ; Rats ; Rats, Inbred OLETF ; Up-Regulation