Vanillin Mitigates the MPTP-Induced α-Synucleinopathy in a Mouse Model of Parkinson's Disease: Insights into the Involvement of Wnt/ß-Catenin Signaling.

BACKGROUND: The abnormal aggregation of α-synuclein (α-syn) in the substantia nigra pars compacta (SNpc) region of the brain is characteristic of Parkinson's disease (PD), leading to the selective demise of neurons. Modifications in the post-translational processing of α-syn, phosphorylation at Ser129 in particular, are implicated in α-syn aggregation and are considered key hallmarks of PD. Furthermore, dysregulated Wnt/ß-catenin signaling, influenced by glycogen synthase kinase-3 beta (GSK-3ß), is implicated in PD pathogenesis. Inhibition of GSK-3ß holds promise in promoting neuroprotection by enhancing the Wnt/ß-catenin pathway. METHODS: In our previous study utilizing 1-methyl-4-phenylpyridinium (MPP+)-administered differentiated SH-SY5Y cells and a PD mouse model, we explored Vanillin's neuroprotective properties and related mechanisms against neuronal loss induced by MPP+/1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration. In the current study, we elucidated the mitigating effects of Vanillin on motor impairments, P-Ser129-α-syn expression, Wnt/ß-catenin signaling, and autophagic neuron death induced by MPTP in a mouse model of PD by performing motor function tests, western blot analysis and immunostaining. RESULTS: Our results show that Vanillin effectively modulated the motor dysfunctions, GSK-3ß expression, and activity, activated the Wnt/ß-catenin signaling, and reduced autophagic neuronal demise in the MPTP-lesioned mice, highlighting its neuroprotective effects. CONCLUSIONS: These findings underscore the complex interplay between α-syn pathology, GSK-3ß, Wnt/ß-catenin signaling, and autophagic-cell death in PD pathogenesis. Targeting these pathways, particularly with Vanillin, can be a promising therapeutic strategy for restoring dopaminergic (DA-ergic) neuronal homeostasis and slowing the progression of PD. Further research is crucial to resolving existing disputes and translating these discoveries into effective therapeutic interventions for PD patients.

Neuroprotection and Mechanism of Gas-miR36-5p from Gastrodia elata in an Alzheimer's Disease Model by Regulating Glycogen Synthase Kinase-3ß.

Alzheimer's disease (AD) is currently the most common neurodegenerative disease. Glycogen synthase kinase 3ß (GSK-3ß) is a pivotal factor in AD pathogenesis. Recent research has demonstrated that plant miRNAs exert cross-kingdom regulation on the target genes in animals. Gastrodia elata (G. elata) is a valuable traditional Chinese medicine that has significant pharmacological activity against diseases of the central nervous system (CNS). Our previous studies have indicated that G. elata-specific miRNA plays a cross-kingdom regulatory role for the NF-κB signaling pathway in mice. In this study, further bioinformatics analysis suggested that Gas-miR36-5p targets GSK-3ß. Through western blot, RT-qPCR, and assessments of T-AOC, SOD, and MDA levels, Gas-miR36-5p demonstrated its neuroprotective effects in an AD cell model. Furthermore, Gas-miR36-5p was detected in the murine brain tissues. The results of the Morris water maze test and western blot analysis provided positive evidence for reversing the learning deficits and hyperphosphorylation of Tau in AD mice, elucidating significant neuroprotective effects in an AD model following G. elata RNA administration. Our research emphasizes Gas-miR36-5p as a novel G. elata-specific miRNA with neuroprotective properties in Alzheimer's disease by targeting GSK-3ß. Consequently, our findings provide valuable insights into the cross-kingdom regulatory mechanisms underlying G. elata-specific miRNA, presenting a novel perspective for the treatment of Alzheimer's disease.

IL-37-induced activation of glycogen synthase kinase 3ß promotes IL-1R8/Sigirr phosphorylation, internalization, and degradation in lung epithelial cells.

Interleukin (IL)-37 diminishes a variety of inflammatory responses through ligation to its receptor IL-1R8/Sigirr. Sigirr is a Toll like receptor/IL-1R family member. We have shown that Sigirr is not stable in response to IL-37 treatment. IL-37-induced Sigirr degradation is mediated by the ubiquitin-proteasome system, and the process is reversed by a deubiquitinase, USP13. However, the molecular mechanisms by which USP13 regulates Sigirr stability have not been revealed. In this study, we investigate the roles of glycogen synthesis kinase 3ß (GSK3ß) in Sigirr phosphorylation and stability. IL-37 stimulation induced Sigirr phosphorylation and degradation, as well as activation of GSK3ß. Inhibition of GSK3ß attenuated IL-37-induced Sigirr phosphorylation, while exogenous expressed GSK3ß promoted Sigirr phosphorylation at threonine (T)372 residue. Sigirr association with GSK3ß was detected. Amino acid residues 51-101 in GSK3ß were identified as the Sigirr binding domain. These data indicate that GSK3ß mediates IL-37-induced threonine phosphorylation of Sigirr. Further, we investigated the role of GSK3ß-mediated phosphorylation of Sigirr in Sigirr degradation. Inhibition of GSK3ß attenuated IL-37-induced Sigirr degradation, while T372 mutant of Sigirr was resistant to IL-37-mediated degradation. Furthermore, inhibition of Sigirr phosphorylation prevented Sigirr internalization and association with USP13, suggesting GSK3ß promotes Sigirr degradation through disrupting Sigirr association with USP13.

Enhanced anticancer activity by the combination of vinpocetine and sorafenib via PI3K/AKT/GSK-3ß signaling axis in hepatocellular carcinoma cells.

Vinpocetine is widely used to treat cerebrovascular diseases. However, the effect of vinpocetine to treat hepatocellular carcinoma (HCC) has not been investigated. In this study, we revealed that vinpocetine was associated with antiproliferative activity in HCC cells, but induced cytoprotective autophagy, which restricted its antitumor activity. Autophagy inhibitors improved the antiproliferative activity of vinpocetine in HCC cells. Sorafenib is effective to treat advanced HCC, but the effect of autophagy induced by sorafenib is indistinct. We demonstrated vinpocetine plus sorafenib suppressed the cytoprotective autophagy activated by vinpocetine in HCC cells and significantly induced apoptosis and suppressed cell proliferation in HCC cells. In addition, vinpocetine plus sorafenib activates glycogen synthase kinase 3ß (GSK-3ß) and subsequently inhibits cytoprotective autophagy induced by vinpocetine in HCC cells. Meanwhile, overexpression of GSK-3ß was efficient to increase the apoptosis induced by vinpocetine plus sorafenib in HCC cells. Our study revealed that vinpocetine plus sorafenib could suppress the cytoprotective autophagy induced by vinpocetine and subsequently show synergistically anti-HCC activity via activating GSK-3ß and the combination of vinpocetine and sorafenib might reverse sorafenib resistance via the PI3K/protein kinase B/GSK-3ß signaling axis. Thus, vinpocetine may be a potential candidate for sorafenib sensitization and HCC treatment, and our results may help to elucidate more effective therapeutic options for HCC patients with sorafenib resistance.

Beta-catenin inhibits bovine parainfluenza virus type 3 replication via innate immunity pathway.

BACKGROUND: Bovine parainfluenza virus type 3 (BPIV3) is one of the important viral respiratory agents associated with the bovine respiratory disease complex (BRDC) in cattle. Previous study has demonstrated that infection of BPIV3 causes innate immune response within the host cell. ß-catenin is a key component of the Wnt/ß-catenin signal pathway which is involved in the regulation of interferon-beta (IFN-ß) transcription. Some viruses can activate while others can inhibit the Wnt/ß-catenin signaling pathway. However, the role of ß-catenin in BPIV3 infection remains unclear. RESULTS: Here we found that the expression of ß-catenin mRNA was up-regulated and ß-catenin protein was down-regulated after BPIV3 infection in MDBK cells. Moreover, it was confirmed that overexpression of ß-catenin suppressed BPIV3 replication and knockdown of ß-catenin promoted viral replication, suggesting that ß-catenin inhibits BPIV3 replication. Furthermore, IFN-ß signal pathway and virus titer analysis using the GSK3ß inhibitor (LiCl) revealed that Wnt/ß-catenin can serve as a mechanism to suppress virus replication in infected cells. The results indicated that LiCl promoted the expression and accumulation in the nucleus of ß-catenin, which further promoted the expression of IFN-ß and OSA1 and suppressed BPIV3 replication. Most importantly, BPIV3 down-regulating ß-catenin protein expression was due to degradation of GSK3ß mediated proteasome pathway. CONCLUSIONS: In summary, we discovered the relationship between ß-catenin and BPIV3 replication. These results provided further insight into the study of BPIV3 pathogenesis.

Lappaconitine Sulfate Inhibits Proliferation and Induces Apoptosis in Human Hepatocellular Carcinoma HepG2 Cells through the Reactive Oxygen Species-Dependent Mitochondrial Pathway.

BACKGROUND: Hepatocellular carcinoma (HCC) is the third leading cause of tumor-related deaths in the word. Lappaconitine (LA), a diterpenoid alkaloid, exerts antitumor activities. However, the effects and mechanisms of LA sulfate (LS) on HCC remain unclear. This study evaluated the activities and explored the underlying mechanisms of LS in HCC cell line HepG2 cells. MATERIALS AND METHODS: The cell viability and proliferation were evaluated using the Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) assay, respectively. The cell cycle distribution was detected by propidium iodide (PI) staining assay. The apoptosis was detected by Annexin -V-fluorescein isothiocyanate (FITC)/PI double staining assay. The cell cycle arrest and apoptosis-related proteins were estimated by western blot analysis. The mitochondrial membrane potential (MMP) was -determined through the 5, 5', 6, 6'-tetrachloro-1, 1', 3, 3'-tetraethylbenzimi-dazolyl carbocyanine iodide (JC-1) staining assay. The reactive oxygen species (ROS) was monitored by 20-70-dichlorofluorescein diacetate (DCFH-DA) staining assay. In vivo antitumor activities were investigated by HepG2 xenograft model. RESULTS: Our results showed that LS significantly -inhibited the viability and proliferation of HepG2 cells. LS triggered G0/G1 cell cycle arrest, apoptosis and caspase activation. Furthermore, LS induced MMP loss and ROS accumulation. Additionally, LS suppressed the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/glycogen synthase kinase 3ß (GSK3ß) signaling pathway. An in vivo assay showed that LS exhibited a pronounced antitumor effect in nude mice bearing HepG2 xenografts. CONCLUSIONS: Our results demonstrated that LS is a promising therapeutic agent for HCC directed -toward the proliferation inhibition and the induction of apoptosis.

Synergistic effect of glucocorticoids and IGF-1 on myogenic differentiation through the Akt/GSK-3ß pathway in C2C12 myoblasts.

Purpose: Glucocorticoids are the only therapeutics that can delay the progression of Duchenne musculardystrophy (DMD), the most prevalent type of inherited neuromuscular disorder in males. However, beyond theiranti-inflammatory effects, glucocorticoids have other underlying mechanisms that remain unclear. Moreover, muscleand circulating levels of insulin growth factor-1 (IGF-1) often decrease in response to glucocorticoids. Therefore, wehypothesized that glucocorticoids, either alone or in combination with IGF-1, can improve myogenic differentiation.Materials and methods: Established C2C12 myoblasts were employed as an in vitro model of myogenic differentiation,and myogenic differentiation markers, as assessed by Western blot (myogenin, MyoD, and MyHC protein expression),cellular morphology analysis (fusion index) and RT-PCR (MCK mRNA expression), were measured.Results: Myogenic differentiation markers were increased by glucocorticoid treatment. Furthermore, this effect was furtherenhanced by IGF-1, and these results suggest that glucocorticoids, either alone or together with IGF-1, can promotemyogenic differentiation. Akt and GSK-3ß play important roles in myogenic differentiation. Interestingly, the levels ofboth phosphorylated Ser473-Akt and phosphorylated Ser9-GSK-3ß were increased by glucocorticoid and IGF-1 cotreatment.Pharmacological manipulation with LY294002 and LiCl was employed to inhibit Akt and GSK-3ß, respectively.We found that cellular differentiability was inhibited by LY294002 and enhanced by LiCl, indicating that theAkt/GSK-3ß signaling pathway is activated by glucocorticoid and IGF-1 treatment to promote myogenic differentiation.Conclusions: Glucocorticoids together with IGF-1 promote myogenic differentiation through the Akt/GSK-3ßpathway. Thus, these results further our knowledge of myogenic differentiation and may offer a potential alternativestrategy for DMD treatment based on glucocorticoid and IGF-1.

Neuroprotective effect of Apelin 13 on ischemic stroke by activating AMPK/GSK-3ß/Nrf2 signaling.

BACKGROUND: Previous studies had showed that Apelin 13 could protect against apoptosis induced by ischemic/reperfusion (I/R). However, the mechanisms whereby Apelin 13 protected brain I/R remained to be elucidated. The present study was designed to determine whether Apelin 13 provided protection through AMPK/GSK-3ß/Nrf2 pathway. METHODS: In vivo, the I/R model was induced and Apelin 13 was given intracerebroventricularly 15 min before reperfusion. The neurobehavioral scores, infarction volumes, and some cytokines in the brain were measured. For in vitro study, PC12 cells were used. To clarify the mechanisms, proteases inhibitors or siRNA were used. Protein levels were investigated by western blotting. RESULTS: The results showed that Apelin 13 treatment significantly reduced infarct size, improved neurological outcomes, decreased brain edema, and inhibited cell apoptosis, oxidative stress, and neuroinflammation after I/R. Apelin 13 significantly increased the expression of Nrf2 and the phosphorylation levels of AMPK and GSK-3ß. Furthermore, in cultured PC12 cells, the same protective effects were also observed. Silencing Nrf2 gene with its siRNA abolished the Apelin 13's prevention of I/R-induced PC12 cell injury, oxidative stress, and inflammation. Inhibition of AMPK by its siRNA decreased the level of Apelin 13-induced Nrf2 expression and diminished the protective effects of Apelin 13. The interplay relationship between GSK-3ß and Nrf2 was also verified with relative overexpression. Using selective inhibitors, we further identified the upstream of AMPK/GSK-3ß/Nrf2 is AR/Gα/PLC/IP3/CaMKK. CONCLUSIONS: In conclusion, the previous results showed that Apelin 13 protected against I/R-induced ROS-mediated inflammation and oxidative stress through activating the AMPK/GSK-3ß pathway by AR/Gα/PLC/IP3/CaMKK signaling, and further upregulated the expression of Nrf2-regulated antioxidant enzymes.

Tardive dyskinesia is associated with altered putamen Akt/GSK-3ß signaling in nonhuman primates.

BACKGROUND: Tardive dyskinesia is a delayed and potentially irreversible motor complication arising from chronic exposure to antipsychotic drugs. Interaction of antipsychotic drugs with G protein-coupled receptors triggers multiple intracellular events. Nevertheless, signaling pathways that might be associated with chronic unwanted effects of antipsychotic drugs remain elusive. In this study, we aimed to better understand kinase signaling associated with the expression of tardive dyskinesia in nonhuman primates. METHODS: We exposed capuchin monkeys to prolonged haloperidol (n = 10) or clozapine (n = 6) treatments. Untreated animals were used as controls (n = 6). Half of haloperidol-treated animals (5) developed mild tardive dyskinesia similar to that found in humans. Using Western blots and immunochemistry, we measured putamen total and phosphorylated protein kinase levels associated with canonical and noncanonical signaling cascades of G protein-coupled receptors. RESULTS: Antipsychotic drugs enhanced pDARPP-32 and pERK1/2, but no difference ws observed in phosphoprotein kinase levels between dyskinetic and nondyskinetic monkeys. On the other hand, comparison of kinase levels between haloperidol-treated dyskinetic and nondyskinetic monkeys indicated that dyskinetic animals had lower GRK6 and ß-arrestin2 levels. Levels of pAkt and pGSK-3ß were also reduced, but only haloperidol-treated monkeys that developed tardive dyskinesia had reduced pGSK-3ß levels, whereas pAkt levels in dyskinetic animals positively correlated with dyskinetic scores. Interestingly, double immunofluorescence labeling showed that putamen dopamine D3 receptor levels were upregulated and that D3/pAkt colocalization was enriched in haloperidol-treated animals displaying tardive dyskinesia. CONCLUSIONS: Our results suggest that upregulation of putamen dopamine D3 receptor and alterations along the noncanonical GRK6/ß-arrestin2/Akt/GSK-3ß molecular cascade are associated with the development of tardive dyskinesia in nonhuman primates. © 2019 International Parkinson and Movement Disorder Society.

The antidepressant-like effect of guanosine is dependent on GSK-3ß inhibition and activation of MAPK/ERK and Nrf2/heme oxygenase-1 signaling pathways.

Although guanosine is an endogenous nucleoside that displays antidepressant-like properties in several animal models, the mechanism underlying its antidepressant-like effects is not well characterized. The present study aimed at investigating the involvement of ERK/GSK-3ß and Nrf2/HO-1 signaling pathways in the antidepressant-like effect of guanosine in the mouse tail suspension test (TST). The immobility time in the TST was taken as an indicative of antidepressant-like responses and the locomotor activity was assessed in the open-field test. Biochemical analyses were performed by Western blotting in the hippocampus and prefrontal cortex (PFC). The combined treatment with sub-effective doses of guanosine (0.01 mg/kg, p.o.) and lithium chloride (a non-selective GSK-3ß inhibitor, 10 mg/kg, p.o.) or AR-A014418 (selective GSK-3ß inhibitor, 0.01 µg/site, i.c.v.) produced a synergistic antidepressant-like effect in the TST. The antidepressant-like effect of guanosine (0.05 mg/kg, p.o.) was completely prevented by the treatment with MEK1/2 inhibitors U0126 (5 µg/site, i.c.v.), PD98059 (5 µg/site, i.c.v.), or zinc protoporphyrin IX (ZnPP) (HO-1 inhibitor, 10 µg/site, i.c.v). Guanosine administration (0.05 mg/kg, p.o.) increased the immunocontent of ß-catenin in the nuclear fraction and Nrf2 in the cytosolic fraction in the hippocampus and PFC. The immunocontent of HO-1 was also increased in the hippocampus and PFC. Altogether, the results provide evidence that the antidepressant-like effect of guanosine in the TST involves the inhibition of GSK-3ß, as well as activation of MAPK/ERK and Nrf2/HO-1 signaling pathways, highlighting the relevance of these molecular targets for antidepressant responses.

Tanshinone IIA Ameliorates Spatial Learning and Memory Deficits by Inhibiting the Activity of ERK and GSK-3ß.

BACKGROUND: Alzheimer disease (AD) is the most common type of dementia which is becoming a primary problem in the present society, but it lacks effective treatment methods and means of AD. Tanshinone IIA (Tan IIA) has been reported to have neuroprotective effects to restrain the Aß25-35-mediated apoptosis. However, few studies try to understand how Aß1-42 affects hyperphosphorylation of tau and how Tan IIA regulates this process at the molecular level. METHODS: Fifty male Sprague-Dawley rats were randomly divided into 5 groups and infused through the lateral ventricle with Aß1-42 except the control group. Then the rats were treated with Tan IIA through intragastric administration for 4 weeks. After the ability of learning and memory being measured, histomorphological examination and Western blot were used to detect the possible mechanism in the AD-associated model rats. RESULTS: We observed that Aß1-42 infusion could induce spatial learning and memory deficits in rats. Simultaneously, Aß1-42 also could reduce the neuron in cornu ammonis 1 and dentate gyrus of hippocampus, as well as increase the levels of cleaved caspase 3, hyperphosphorylated tau at the sites Ser396, Ser404, and Thr205 with enhancing staining of black granules in brain. We also found that Aß1-42 could increase the activity of extracellular signal-regulated protein kinase (ERK) and glycogen synthase kinase-3ß (GSK-3ß). Meanwhile, these phenomena could be ameliorated when Tan IIA was used. CONCLUSION: We concluded that Tan IIA might have neuroprotective effect and improving learning and memory ability to be a viable candidate in AD therapy with mechanisms involving the ERK and GSK-3ß signal pathway.

The neuroprotective effect of agmatine against amyloid ß-induced apoptosis in primary cultured hippocampal cells involving ERK, Akt/GSK-3ß, and TNF-α.

ß-Amyloid peptide (Aß), the major element of senile plaques in Alzheimer's disease (AD), has been found to accumulate in brain regions critical for memory and cognition. Deposits of Aß trigger neurotoxic events which lead to neural apoptotic death. The present study examined whether agmatine, an endogenous polyamine formed by the decarboxylation of L-arginine, possesses a neuroprotective effect against Aß-induced toxicity. Primary rat hippocampal cells extracted from the brains of 18-19-day-old embryos were exposed to 10 µM of Aß (25-35) in the absence or presence of agmatine at 150 or 250 µM. Additionally, the involvement of Akt (Protein Kinae B), GSK-3ß (glycogen synthase kinase 3-ß), ERK (Extracellular Signal-Regulated Kinase) and TNF-α (Tumor necrosis factor-α) in the agmatine protection against Aß-induced neurotoxicity was investigated. Agmatine significantly prevented the effect of Aß exposure on cell viability and caspase-3 assays. Furthermore, agmatine considerably restored Aß-induced decline of phospho-Akt and phospho-GSK and blocked Aß-induced increase of phospho-ERK and TNF-alpha. Taken together, these findings might shed light on the protective effect of agmatine as a potential therapeutic agent for AD.

Baicalin attenuated substantia nigra neuronal apoptosis in Parkinson's disease rats via the mTOR/AKT/GSK-3ß pathway.

This focus of our research is to investigate the protective effect of Baicalin on apoptosis and mTOR/AKT/GSK-3ß pathway in substantia nigra neurons in a rat model for Parkinson's disease, induced by 6-Hydroxydopamine. Thirty healthy female Sprague-Dawley rats were randomly divided into control group, model group, and Baicalin group. The Parkinson model was established by injecting 6-Hydroxydopamine into the right substantia nigra of rats in model and Baicalin group. The rats in Baicalin group were intragastrically administered with Baicalin (25 mg/kg/day) for four weeks. At the same time, the rats in control and model groups were intragastrically administered with equivalent solvents. We observed the rat turns, rotation speed and left forelimb usage. The protein expression levels of α-SYN, mTOR, AKT, and GSK-3ß in substantia nigra were detected by immunohistochemistry and Western blotting. Compared with model group, Baicalin significantly reduced the number of rotation speeds and neuron apoptosis (P < 0.001, respectively). However, the left forelimb use rate was notably increased after treatment with Baicalin (P < 0.001, respectively). Also, Baicalin decreased the expression levels of α-SYN, mTOR, AKT, and GSK-3ß in rats when compared with those in model group (P < 0.001, respectively).

Sigma 1 Receptor Antagonists Inhibit Manic-Like Behaviors in Two Congenital Strains of Mice.

Background: Several currently available animal models reproduce select behavioral facets of human mania as well as the abnormal glutamatergic neurotransmission and dysregulation of glycogen synthase kinase 3ß that accompanies this disease. Methods: In this study, we addressed the therapeutic potential of ligands of sigma receptor type 1 (σ1R) in 2 putative models of mania: the "manic" Black Swiss outbred mice from Taconic farms (BStac) and mice with the 129 genetic background and histidine triad nucleotide-binding protein 1 (HINT1) deletion (HINT1-/- mice) that exhibit bipolar-like behaviors. Results: The activity of control mice, which do not exhibit manic-like behaviors in the forced swim test, was significantly enhanced by MK801, an inhibitor of glutamate N-methyl-D-aspartate receptor activity, an effect that was not or barely observed in manic-like mice. Typical mood stabilizers, such as glycogen synthase kinase 3ß inhibitors, but not σ1R ligands, reduced the N-methyl-D-aspartate receptor-mediated behaviors in control mice. Notably, σ1R antagonists S1RA, PD144418, BD1047, and BD1063, but not σ1R agonists PRE084 and PPCC, attenuated the manic-like behaviors of BStac and HINT1-/- mice by increasing antiactivity behaviors. The antimanic effects of a single administration of σ1R antagonists persisted for at least 24 hours, and these drugs did not alter the behavior of the "bipolar" HINT1-/- mice during pro-depressive episodes. Conclusions: σ1R antagonists exhibit a selective normalizing effect on specific behavioral domains of mania without altering control (normal) or depressive-like behaviors.

Adiponectin Attenuates Streptozotocin-Induced Tau Hyperphosphorylation and Cognitive Deficits by Rescuing PI3K/Akt/GSK-3ß Pathway.

Clinical studies have demonstrated that decreased adiponectin is associated with the development of Type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD). We focused on determining the neuroprotective effect offered by adiponectin against streptozotocin-induced brain damage in ICV-STZ rat model. We found that adiponectin supplements significantly restored the cognitive deficits in ICV-STZ rat model including shorter escape latency, more crossing times and increased time spent in the target quadrant. Adiponectin supplements also increased number of dendritic branches and mushroom percentage. In addition, adiponectin supplements attenuated tau hyperphosphorylation at multiple AD-related sites through activation of protein Ser9-phosphorylated glycogen synthase kinase-3ß (Ser9-GSK-3ß) with increased the Akt and PI3K activity. Our data suggest that adiponectin supplements have neuroprotective effects on the ICV-STZ rat model, which may be mediated by the activation of the PI3K/Akt/GSK-3ß signaling pathway.

Protective Effects of Oleuropein Against Cerebral Ischemia/Reperfusion by Inhibiting Neuronal Apoptosis.

BACKGROUND In this study, we investigated the potential neuroprotective effect of oleuropein (OLE) on apoptotic changes via modulating Akt/glycogen synthase kinase 3 beta (Akt/GSK-3b) signaling in a rat model of cerebral ischemia/reperfusion injury (IRI). MATERIAL AND METHODS Sprague-Dawley male rats (12 weeks, n=200) were randomly assigned to 5 groups: sham group, vehicle (IRI+ vehicle) group, OLE (IRI+OLE) group, OLE+LY294002 (IRI+OLE+LY294002) group, and LY294002(IRI+LY294002) group. The rats were subjected to cerebral ischemia/reperfusion injury (IRI) model and treated once daily for 5 days with vehicle and OLE (100 mg/kg via intraperitoneal injection) after IRI injury. LY294002 (0.3 mg/kg) was intraperitoneally injected once at 30 min after IRI injury. Brain edema, neurological deficit, rotarod latencies, and Morris water maze (MWM) performance were evaluated after IRI. The number of dead cells were assayed by TUNEL staining. Western blot was used to detect the expression of Bcl-2, Bax, cleaved caspase-3 (CC3), neurotrophic factors, and the phosphorylation levels of Akt and GSK-3ß. RESULTS Compared with the vehicle group, brain water content, neurological deficits, rotarod latencies, and escape latency following IRI were reduced in the OLE group. Cell apoptosis and reduced neurotrophic factor caused by IRI was also attenuated by OLE. Furthermore, increased p-Akt and decreased p-GSK-3ß were caused by OLE, which were associated with decrease of Bax/Bcl-2 ratio and the suppression of Caspase-3 activity after IRI. Importantly, all the beneficial effects of OLE in the vehicle group were abrogated by PI3K inhibitor LY294002. CONCLUSIONS Cerebral ischemia was protected by OLE via suppressing apoptosis through the Akt/GSK-3ß pathway and upregulating neurotrophic factor after IRI.

Nanoquinacrine caused apoptosis in oral cancer stem cells by disrupting the interaction between GLI1 and ß catenin through activation of GSK3ß.

Presences of cancer stem cells (CSCs) in a bulk of cancer cells are responsible for tumor relapse, metastasis and drug resistance in oral cancer. Due to high drug efflux, DNA repair and self-renewable capacity of CSCs, the conventional chemotherapeutic agents are unable to kill the CSCs. CSCs utilizes Hedgehog (HH-GLI), WNT-ß catenin signalling for its growth and development. GSK3ß negatively regulates both the pathways in CSCs. Here, we have shown that a nano-formulated bioactive small molecule inhibitor Quinacrine (NQC) caused apoptosis in oral cancer stem cells (OCSCs; isolated from different oral cancer cells and oral cancer patient derived primary cells) by down regulating WNT-ß catenin and HH-GLI components through activation of GSK3ß. NQC activates GSK3ß in transcriptional and translational level and reduces ß catenin and GLI1 as well as downstream target gene of both the pathways Cyclin D1, C-Myc. The transcription factor activity of both the pathways was also reduced by NQC treatment. GSK3ß, ß catenin and GLI1 interacts with each other and NQC disrupts the co-localization and interaction between ß catenin and GLI1 in OCSCs in a dose dependent manner through activation of GSK3ß. Thus, data suggest NQC caused OCSCs death by disrupting the crosstalk between ß catenin and GLI1 by activation of GSK3ß.

Lymphocyte Phospho-Ser-9-GSK-3ß/Total GSK-3ß Protein Levels Ratio Is Not Affected by Chronic Lithium or Valproate Treatment in Euthymic Patients With Bipolar Disorder.

BACKGROUND: Glycogen synthase kinase-3 (GSK-3) inhibition by lithium has been well established in vitro, but proof that this biochemical effect mediates lithium's beneficial action in patients with bipolar disorder is lacking. We studied whether lymphocyte GSK-3ß activity measured indirectly in lithium- or valproate (VPA)-treated euthymic patients with bipolar disorder is different from controls. METHODS: Lymphocyte total and Ser-9-phospho-GSK-3ß (inactive) levels were measured by Western blotting. Forty-seven patients with bipolar disorder and 32 age- and sex-matched control subjects were studied. RESULTS: No significant differences were found between lithium- and VPA-treated patients and controls in phospho-GSK-3ß, total GSK-3ß, or their ratio. CONCLUSIONS: The data do not support the concept that in vivo, during chronic treatment of bipolar illness, GSK-3ß is inhibited either by lithium or by VPA.

Genetic and Pharmacologic Targeting of Glycogen Synthase Kinase 3ß Reinforces the Nrf2 Antioxidant Defense against Podocytopathy.

Evidence suggests that the glycogen synthase kinase 3 (GSK3)-dictated nuclear exclusion and degradation of Nrf2 is pivotal in switching off the self-protective antioxidant stress response after injury. Here, we examined the mechanisms underlying this regulation in glomerular disease. In primary podocytes, doxorubicin elicited cell death and actin cytoskeleton disorganization, concomitant with overactivation of GSK3ß (the predominant GSK3 isoform expressed in glomerular podocytes) and minimal Nrf2 activation. SB216763, a highly selective small molecule inhibitor of GSK3, exerted a protective effect that depended on the potentiated Nrf2 antioxidant response, marked by increased Nrf2 expression and nuclear accumulation and augmented production of the Nrf2 target heme oxygenase-1. Ectopic expression of the kinase-dead mutant of GSK3ß in cultured podocytes reinforced the doxorubicin-induced Nrf2 activation and prevented podocyte injury. Conversely, a constitutively active GSK3ß mutant blunted the doxorubicin-induced Nrf2 response and exacerbated podocyte injury, which could be abolished by treatment with SB216763. In murine models of doxorubicin nephropathy or nephrotoxic serum nephritis, genetic targeting of GSK3ß by doxycycline-inducible podocyte-specific knockout or pharmacologic targeting by SB216763 significantly attenuated albuminuria and ameliorated histologic signs of podocyte injury, including podocytopenia, loss of podocyte markers, podocyte de novo expression of desmin, and ultrastructural lesions of podocytopathy (such as foot process effacement). This beneficial outcome was likely attributable to an enhanced Nrf2 antioxidant response in glomerular podocytes because the selective Nrf2 antagonist trigonelline abolished the proteinuria-reducing and podocyte-protective effect. Collectively, our results suggest the GSK3ß-regulated Nrf2 antioxidant response as a novel therapeutic target for protecting podocytes and treating proteinuric glomerulopathies.

IGF-1 protects dopamine neurons against oxidative stress: association with changes in phosphokinases.

Insulin-like growth factor-1 (IGF-1) is an endogenous peptide transported across the blood brain barrier that is protective in several brain injury models, including an acute animal model of Parkinson's disease (PD). Motor deficits in PD are due largely to the progressive loss of nigrostriatal dopaminergic neurons. Thus, we examined the neuroprotective potential of IGF-1 in a progressive model of dopamine deficiency in which 6-hydroxydopamine (6-OHDA) is infused into the striatum. Rats received intrastriatal IGF-1 (5 or 50 µg) 6 h prior to infusion of 4 µg 6-OHDA into the same site and were euthanized 1 or 4 weeks later. Both concentrations of IGF-1 protected tyrosine hydroxylase (TH) immunoreactive terminals in striatum at 4 weeks but not at 1 week, indicating that IGF-induced restoration of the dopaminergic phenotype occurred over several weeks. TH-immunoreactive cell loss was only attenuated with 50 µg IGF-1. We then examined the effect of striatal IGF-1 on the Ras/ERK1/2 and PI3K/Akt pathways to ascertain whether their activation correlated with IGF-1-induced protection. Striatal and nigral levels of phospho-ERK1/2 were maximal 6 h after IGF-1 infusion and, with the exception of an increase in nigral pERK2 at 48 h, returned to basal levels by 7 days. Phospho-Akt (Ser473) was elevated 6-24 h post-IGF-1 infusion in both striatum and substantia nigra concomitant with inhibition of pro-death GSK-3ß, a downstream target of Akt. These results suggest that IGF-1 can protect the nigrostriatal pathway in a progressive PD model and that this protection is preceded by activation of key pro-survival signaling cascades.