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

Animals ; Drug Tolerance ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; Morphine ; Phosphorylation ; Rats ; Signal Transduction

OBJECTIVEThis study was purposed to detect the expressions of β-catenin and P-GSK-3 β in Wnt signaling pathway of patients with mantle cell lymphoma(MCL), and investigate its relationship with the pathogenesis of MCL.

METHODSThe expression levels of β -catenin protein and P-GSK-3 protein in mantle cell lymphoma and hyperplastic lymphadenitis were detected by using anti-β-catenin, P-GSK-3β polyclonal antibody and S-P staining technique.

RESULTSThe abnormal expression of β-catenin protein(73.33%) in mantle cell lymphoma group was significantly higher than that (6.7%) in reactive lymph node hyperplasia group (P<0.05); and the positive rate of P-GSK-3 β(66.67%) in mantle cell lymphoma group was significantly higher than that (16.67%) in reactive hyperplasia of lymph node group (P<0.05). Spearman correlation analysis showed that there was obvious positive correlation (R=0.852, P<0.01).

CONCLUSIONThe abnormal high expressions of β-catenin and P-GSK-3 β protein have been confirmed to appeare in mantle cell lymphoma.

Glycogen Synthase Kinase 3 ; Glycogen Synthase Kinase 3 beta ; Humans ; Lymphoma, Mantle-Cell ; Signal Transduction ; Wnt Signaling Pathway ; beta Catenin

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

BACKGROUND: Neurodegenerative diseases (ND) are associated with oxidative stress, and antioxidants including epigallocatechin gallate (EGCG) have been tried as potential therapeutic regimens of an experimental model of ND. We performed this study to determine the neuroprotective role of EGCG on up stream and down stream signals in oxidative-stress-injured PC12 cells by exposing them to H2O2. METHODS: Following 100 microM H2O2 exposure, the viability of PC12 cells (not pretreated vs EGCG or z-VAD-fmk pretreated) was evaluated by using a MTT assay. Immunoreactivity (IR) of cytochrome c, caspase-3, poly (ADP-ribose) polymerase (PARP), PI3K/Akt and GSK-3 was examined by using a Western blot. RESULTS: EGCG or z-VAD-fmk pretreated PC12 cells showed increased viability. Dose-dependent inhibition of caspase-3 activation and PARP cleavage was demonstrated by the pretreatment of both agents. However, the inhibition of cytochrome c release was only detected in EGCG pretreated cells. On the pathway through PI3K/Akt and GSK-3, however, the result of a western blot in EGCG pretreated cells showed decreased IR of Akt and GSK-3 and increased IR of p85a PI3K, phosphorylated Akt and GSK-3, and contrasted with that in z-VAD-fmk pretreated cells showing no changes. CONCLUSIONS: These data show that EGCG affects apoptotic pathways through upstream signals including PI3K/Akt and GSK-3 pathways as well as downstream signals including cytochrome c and caspase-3 pathways. Therefore, these results suggest that EGCG mediated activation of PI3K/Akt and inhibition GSK-3 could be a new protective mechanism on the pathogenesis of ND.
Animals ; Antioxidants ; Apoptosis ; Blotting, Western ; Caspase 3 ; Cytochromes c ; Glycogen Synthase Kinase 3 ; Glycogen Synthase* ; Glycogen* ; Models, Theoretical ; Neurodegenerative Diseases ; Oxidative Stress ; PC12 Cells* ; Rivers

BACKGROUND: G93A or A4V mutations in the human Cu/Zn- superoxide dismutase gene (hSOD1) cause familial amyotrophic lateral sclerosis (fALS). However, it has not yet clearly understood how these bring about fALS. We investigated the effects of the G93A or A4V mutations in hSOD1 on the phosphatydilinositol-3-kinase (PI3K)/Akt and glycogen synthase kinase-3 (GSK-3) pathway, and effects of GSK-3 inhibitor on the G93A- or A4V-mutant cells. METHODS: To evaluate those effects, VSC4.1 motoneuron cells were transfected with G93A- or A4V-mutant types of hSOD1 (G93A and A4V cells, respectively) with/without GSK-3 inhibitor were compared with them transfected with wild type (wild cells) in cell viability and intracellular signals, including PI3K/Akt, GSK-3, and caspase-3, 24 hours after neuronal differentiation. RESULTS: Compared with wild cells, MTT assay revealed a greatly reduced viability in G93A and A4V cells without GSK-3 inhibitor. However, treatment with GSK-3 inhibitor increased the viability of G93A and A4V cells. Western blotting showed that PI3K and pAkt were decreased, and GSK-3 and caspase-3 were increased in G93A and A4V cells, and that GSK-3 inhibitor treatment reduced caspase-3 but did not affected PI3K, Akt and GSK-3. CONCLUSIONS: These results suggest that the G93A or A4V mutations induce inhibition of PI3K/Akt and activation of GSK-3 and caspase-3 resulting the vulnerability to oxidative stress, and that GSK-3 mediated cell death mechanism is important in G93A and A4V cell death.
Amyotrophic Lateral Sclerosis ; Blotting, Western ; Caspase 3 ; Cell Death* ; Cell Survival ; Glycogen Synthase Kinase 3 ; Glycogen Synthase* ; Glycogen* ; Humans ; Motor Neurons* ; Neurons ; Oxidative Stress ; Superoxide Dismutase

OBJECTIVETo investigate the role of the key intracellular signaling molecule glycogen synthase kinase-3 beta in the mechanism of liver ischemia reperfusion (IR).

METHODSC57BL/6 mice were subjected to 90 min warm liver cephalad lobe ischemia, followed by various length of reperfusion. Experiment groups included sham control group, liver IRI model group and glycogen synthase kinase-3 beta inhibitor-treated group (SB216763 in DMSO, 25 g/kg, i.p, 2 hour prior to the onset of liver ischemia). The expression of glycogen synthase kinase-3 beta protein was analysed by Western blotting. The serum ALT levels were determined to reflect the function of liver. The affected liver lobes were harvested for histology analysis. The inflammatory gene expression was detected by Quantitative PCR.

RESULTSBy western blot analysis, we found that ischemia itself activated glycogen synthase kinase-3 beta by a significant decrease of its phosphorylation. Glycogen synthase kinase-3 beta inhibitor SB216763-pretreatment ameliorated the liver damages significantly as compared to the controls (sALT: 2046+/-513 U/L vs 5809+/-1689 U/L, P = 0.0153), and suppressed the gene expressions of IL-12, TNFa, IL-1b and IL-6.

CONCLUSIONSThis study demonstrated that the ischemia process modulated liver innate immune activation via a GSK-3-dependent mechanism which favored the development of a pro-inflammation response and lead to liver tissue damages. GSK-3b may be a new therapeutic target to ameliorate liver IRI in transplant patients.

Animals ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; Inflammation ; metabolism ; Liver ; metabolism ; pathology ; Male ; Mice ; Mice, Inbred C57BL ; Reperfusion Injury ; metabolism ; pathology

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

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

Animals ; Apoptosis ; Cardiomegaly ; metabolism ; pathology ; Glycogen Synthase Kinase 3 ; metabolism ; Mice ; Mice, Transgenic ; Myocytes, Cardiac ; cytology