scholarly journals Activation of GSK-3 and phosphorylation of CRMP2 in transgenic mice expressing APP intracellular domain

2005 ◽  
Vol 171 (2) ◽  
pp. 327-335 ◽  
Author(s):  
Kathleen A. Ryan ◽  
Sanjay W. Pimplikar

Amyloid precursor protein (APP), implicated in Alzheimer's disease, is a trans-membrane protein of undetermined function. APP is cleaved by γ-secretase that releases the APP intracellular domain (AICD) in the cytoplasm. In vitro studies have implicated AICD in cell signaling and transcriptional regulation, but its biologic relevance has been uncertain and its in vivo function has not been examined. To investigate its functional role, we generated AICD transgenic mice, and found that AICD causes significant biologic changes in vivo. AICD transgenic mice show activation of glycogen synthase kinase-3β (GSK-3β) and phosphorylation of CRMP2 protein, a GSK-3β substrate that plays a crucial role in Semaphorin3a-mediated axonal guidance. Our data suggest that AICD is biologically relevant, causes significant alterations in cell signaling, and may play a role in axonal elongation or pathfinding.

Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 610
Author(s):  
Robin Park ◽  
Andrew L. Coveler ◽  
Ludimila Cavalcante ◽  
Anwaar Saeed

Glycogen synthase kinase-3 beta is a ubiquitously and constitutively expressed molecule with pleiotropic function. It acts as a protooncogene in the development of several solid tumors including pancreatic cancer through its involvement in various cellular processes including cell proliferation, survival, invasion and metastasis, as well as autophagy. Furthermore, the level of aberrant glycogen synthase kinase-3 beta expression in the nucleus is inversely correlated with tumor differentiation and survival in both in vitro and in vivo models of pancreatic cancer. Small molecule inhibitors of glycogen synthase kinase-3 beta have demonstrated therapeutic potential in pre-clinical models and are currently being evaluated in early phase clinical trials involving pancreatic cancer patients with interim results showing favorable results. Moreover, recent studies support a rationale for the combination of glycogen synthase kinase-3 beta inhibitors with chemotherapy and immunotherapy, warranting the evaluation of novel combination regimens in the future.


Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5391
Author(s):  
Zheng Liu ◽  
Ming Bian ◽  
Qian-Qian Ma ◽  
Zhuo Zhang ◽  
Huan-Huan Du ◽  
...  

A series of novel synthetic substituted benzo[d]oxazole-based derivatives (5a–5v) exerted neuroprotective effects on β-amyloid (Aβ)-induced PC12 cells as a potential approach for the treatment of Alzheimer’s disease (AD). In vitro studies show that most of the synthesized compounds were potent in reducing the neurotoxicity of Aβ25-35-induced PC12 cells at 5 μg/mL. We found that compound 5c was non-neurotoxic at 30 μg/mL and significantly increased the viability of Aβ25-35-induced PC12 cells at 1.25, 2.5 and 5 μg/mL. Western blot analysis showed that compound 5c promoted the phosphorylation of Akt and glycogen synthase kinase (GSK-3β) and decreased the expression of nuclear factor-κB (NF-κB) in Aβ25-35-induced PC12 cells. In addition, our findings demonstrated that compound 5c protected PC12 cells from Aβ25-35-induced apoptosis and reduced the hyperphosphorylation of tau protein, and decreased the expression of receptor for AGE (RAGE), β-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1), inducible nitric oxide synthase (iNOS) and Bcl-2-associated X protein/B-cell lymphoma 2 (Bax/Bcl-2) via Akt/GSK-3β/NF-κB signaling pathway. In vivo studies suggest that compound 5c shows less toxicity than donepezil in the heart and nervous system of zebrafish.


2020 ◽  
Vol 11 (10) ◽  
Author(s):  
Jikui Sun ◽  
Quanfeng Ma ◽  
Banban Li ◽  
Chen Wang ◽  
Lidong Mo ◽  
...  

Abstract Accumulating evidence indicates that the dysregulation of the miRNAs/mRNA-mediated carcinogenic signaling pathway network is intimately involved in glioma initiation and progression. In the present study, by performing experiments and bioinformatics analysis, we found that RPN2 was markedly elevated in glioma specimens compared with normal controls, and its upregulation was significantly linked to WHO grade and poor prognosis. Knockdown of RPN2 inhibited tumor proliferation and invasion, promoted apoptosis, and enhanced temozolomide (TMZ) sensitivity in vitro and in vivo. Mechanistic investigation revealed that RPN2 deletion repressed β-catenin/Tcf-4 transcription activity partly through functional activation of glycogen synthase kinase-3β (GSK-3β). Furthermore, we showed that RPN2 is a direct functional target of miR-181c. Ectopic miR-181c expression suppressed β-catenin/Tcf-4 activity, while restoration of RPN2 partly reversed this inhibitory effect mediated by miR-181c, implying a molecular mechanism in which TMZ sensitivity is mediated by miR-181c. Taken together, our data revealed a new miR-181c/RPN2/wnt/β-catenin signaling axis that plays significant roles in glioma tumorigenesis and TMZ resistance, and it represents a potential therapeutic target, especially in GBM.


2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Tianqing Peng ◽  
Yanpeng Wang ◽  
Jian Ma

Background: Doxorubicin causes damage to the heart, which may present as cardiomyopathy. However, the mechanisms by which doxorubicin induces cardiotoxicity remain not fully understood and no effective prevention for doxorubicin cardiomyopathy is available. Calpains, a family of calcium-dependent thiol-proteases, have been implicated in cardiovascular diseases. Their activities are tightly controlled by calpastatin. This study employed transgenic mice over-expressing calpastatin to investigate the role of calpain in doxorubicin-induced cardiotoxicity. Methods and Results: Doxorubicin treatment decreased calpain activities in cultured neonatal mouse cardiomyocytes and in vivo mouse hearts. Over-expression of calpastatin or incubation with pharmacological calpain inhibitors enhanced caspase-3 activity and DNA fragmentation in both neonatal and adult cardiomyocytes induced by doxorubicin. Inhibition of calpain also induced down-regulation of phosphorylated protein kinase B (AKT, Thr308), and a concomitant reduction in glycogen synthase kinase-3beta (GSK-3β) phosphorylation (Ser9) in doxorubicin-treated cardiomyocytes. Blocking AKT further increased doxorubicin-induced cardiac injuries, suggesting the effects of calpain inhibition may be mediated by inactivating the AKT/GSK-3β signaling. In an in vivo model of doxorubicin-induced cardiotoxicity, over-expression of calpastatin decreased calpain activities and exacerbated myocardial dysfunction as assessed by echocardiography and hemodynamic measurement in transgenic mice (C57BL/6) 5 days after doxorubicin injection. The five-day mortality was higher in transgenic mice (29.16%) compared with their wild-type littermates (8%) after doxorubicin treatment. Conclusions: Over-expression of calpastatin enhances doxorubicin-induced cardiac injuries through inhibiting calpain and compromising AKT survival signaling. Thus, calpains may protect cardiomyocytes against doxorubicin-induced cardiotoxicity.


2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
YI TAN ◽  
Xiaoqing Yan ◽  
Shanshan Zhou ◽  
Yong Li ◽  
Yan Li ◽  
...  

Cardiac insulin resistance is a key pathogenic factor for diabetic cardiomyopathy, but its mechanism remains largely unclear. Here we demonstrated that diabetes significantly inhibited cardiac Akt phosphorylation from 2 weeks to 2 months in wide-type (WT) mice, but not in cardiac-specific metallothionein-transgenic (MT-TG) mice. Cardiac Akt2 expression and phosphorylation was decreased and insulin-induced cardiac Akt2 and GSK-3β phosphorylation and glycogen synthase dephosphorylation were also decreased in WT, but not MT-TG, diabetic mice. Deletion of the Akt2 gene either in vitro H9c2 cells or in vivo significantly impaired cardiac glucose metabolic signaling. In addition, diabetes significantly increased cardiac Akt negative regulator tribbles (TRB)3 expression only in WT mice, suggesting the possible contribution of MT inhibition of diabetic up-regulation of TRB3 to Akt2 function preservation. Cardiac H9c2 cells with and without forced MT-overexpression (MT-H9c2) were treated with tert-butyl hydroperoxide (tBHP), which significantly reduced Akt2 phosphorylation in both basal and insulin-stimulating conditions only in H9c2 cells. Silencing TRB3 expression with SiRNA completely prevented tBHP’s inhibition of insulin-stimulated Akt2 phosphorylation in H9c2 cells, while overexpression of TRB3 in MT-H9c2 cells completely abolished MT preservation of insulin-stimulated Akt2 phosphorylation. Forced-overexpression of TRB3 by adenovirus-mediated gene delivery in MT-TG hearts also abolished MT’s preservation of cardiac insulin signaling and prevention of diabetic cardiomyopathy. These results suggest that diabetes-attenuated cardiac Akt2 function via up-regulating TRB3 plays a critical role in diabetic inhibition of insulin signaling in the heart. MT preserved cardiac Akt2-mediated insulin signaling by inhibiting TRB3, leading to the prevention of diabetic cardiomyopathy.


2012 ◽  
Vol 116 (4) ◽  
pp. 868-881 ◽  
Author(s):  
Chung-Hsi Hsing ◽  
Yu-Hong Chen ◽  
Chia-Ling Chen ◽  
Wei-Ching Huang ◽  
Ming-Chung Lin ◽  
...  

Background Overdose propofol treatment with a prolong time causes injury to multiple cell types; however, its molecular mechanisms remain unclear. Activation of glycogen synthase kinase (GSK)-3β is proapoptotic under death stimuli. The authors therefore hypothesize that propofol overdose induces macrophage apoptosis through GSK-3β. Methods Phagocytic analysis by uptake of Staphylococcus aureus showed the effects of propofol overdose on murine macrophages RAW264.7 and BV2 and primary human neutrophils in vitro. The authors further investigated cell apoptosis in vitro and in vivo, lysosomal membrane permeabilization, and the loss of mitochondrial transmembrane potential (MTP) by propidium iodide, annexin V, acridine orange, and rhodamine 123 staining, respectively. Protein analysis identified activation of apoptotic signals, and pharmacologic inhibition and genetic knockdown using lentiviral-based short hairpin RNA were further used to clarify their roles. Results A high dose of propofol caused phagocytic inhibition and apoptosis in vitro for 24 h (25 μg/ml, in triplicate) and in vivo for 6 h (10 mg/kg/h, n = 5 for each group). Propofol induced lysosomal membrane permeabilization and MTP loss while stabilizing MTP and inhibiting caspase protected cells from mitochondrial apoptosis. Lysosomal cathepsin B was required for propofol-induced lysosomal membrane permeabilization, MTP loss, and apoptosis. Propofol decreased antiapoptotic Bcl-2 family proteins and then caused proapoptotic Bcl-2-associated X protein (Bax) activation. Propofol-activated GSK-3β and inhibiting GSK-3β prevented Mcl-1 destabilization, MTP loss, and lysosomal/mitochondrial apoptosis. Forced expression of Mcl-1 prevented the apoptotic effects of propofol. Decreased Akt was important for GSK-3β activation caused by propofol. Conclusions These results suggest an essential role of GSK-3β in propofol-induced lysosomal/mitochondrial apoptosis.


1999 ◽  
Vol 277 (2) ◽  
pp. E299-E307 ◽  
Author(s):  
Sanjay Bhanot ◽  
Baljinder S. Salh ◽  
Subodh Verma ◽  
John H. McNeill ◽  
Steven L. Pelech

The effects of tail-vein insulin injection (2 U/kg) on the regulation of protein-serine kinases in hindlimb skeletal muscle were investigated in hyperinsulinemic hypertensive fructose-fed (FF) animals that had been fasted overnight. Basal protein kinase B (PKB) activity was elevated about twofold in FF rats and was not further stimulated by insulin. Phosphatidylinositol 3-kinase (PI3K), which lies upstream of PKB, was increased ∼3.5-fold within 2–5 min by insulin in control rats. Basal and insulin-activated PI3K activities were further enhanced up to 2-fold and 1.3-fold, respectively, in FF rats. The 70-kDa S6 kinase (S6K) was stimulated about twofold by insulin in control rats. Both basal and insulin-stimulated S6K activity was further enhanced up to 1.5-fold and 3.5-fold, respectively, in FF rats. In control rats, insulin caused a 40–50% reduction of the phosphotransferase activity of the β-isoform of glycogen synthase kinase 3 (GSK-3β), which is a PKB target in vitro. Basal GSK-3β activity was decreased by ∼40% in FF rats and remained unchanged after insulin treatment. In summary, 1) the PI3K → PKB → S6K pathway was upregulated under basal conditions, and 2) insulin stimulation of PI3K and S6K activities was enhanced, but both PKB and GSK-3 were refractory to the effects of insulin in FF rats.


2020 ◽  
Author(s):  
Ya-ping Yu ◽  
Qiang-ping Wang ◽  
Jian-Ying Shen ◽  
Nan-xiang Xiong ◽  
Hua Yu ◽  
...  

AbstractNogo-66, the extracellular domain of Nogo-A, has been identified as the most important myelin-associated neuronal growth inhibitor. Evidence suggested that Nogo-66 exert its neurite inhibition effect via a Nogo-66/Protein kinase B (PKB)/Glycogen synthase kinase-3β (GSK-3β)/tau signaling pathway. Integrin-linked kinase (ILK) is a serine/threonine kinase mediating axon upstream growth of PKB and GSK-3β. However, the contribution of ILK to the Nogo-66-induced inhibition of neurite, is not clear. In this study, we set out to reveal the role of ILK on Nogo-66 signaling in vitro and in vivo. To deteremine this directly, Recombinant adenoviruses were constructed to upregulate or downregulate the expresioon of ILK in Neuro 2a (N2a)and analysis the change of downstream molecule and neurite length. The results showed that Nogo-66 inhibited the phosphorylation of ILK, while ILK regulated the phosphorylation of PKB and GSK-3β, and the expression of tau in Nogo-66-treated N2a cells. ILK overexpression through lentivirus vector transfection reduced the inhibitory effect of neurite outgrowth induced by Nogo-66 in cortical neurons. The Tau expression in the complete spinal cord transection rat model was promoted by the overexpression of ILK. Our findings indicated that ILK is a key signal factor involved in Nogo-66-induced inhibition of neurite outgrowth. The mechanism of Nogo-66 signaling pathway was further explained and a proper target for the promotion of neural regeneration was also provided by this study.


RSC Advances ◽  
2016 ◽  
Vol 6 (49) ◽  
pp. 43345-43355 ◽  
Author(s):  
Mushtaq A. Tantray ◽  
Imran Khan ◽  
Hinna Hamid ◽  
Mohammad Sarwar Alam ◽  
Abhijeet Dhulap ◽  
...  

Synthesized benzimidazole based 1,3,4-oxadiazole-1,2,3-triazole conjugates were found to inhibit GSK-3β activityin vitroand exhibit antidepressant-like activity inin vivostudies.


2005 ◽  
Vol 288 (4) ◽  
pp. F642-F649 ◽  
Author(s):  
Reena Rao ◽  
Ming-Zhi Zhang ◽  
Min Zhao ◽  
Hui Cai ◽  
Raymond C. Harris ◽  
...  

The use of LiCl in clinical psychiatry is routinely complicated by overt nephrogenic diabetes insipidus (NDI), the mechanism of which is incompletely understood. In vitro studies indicate that lithium can induce renal medullary interstitial cell cyclooxygenase 2 (COX2) protein expression via inhibition of glycogen synthase kinase-3β (GSK-3β). Both COX1 and COX2 are expressed in the kidney. Renal prostaglandins have been suggested to play an important role in lithium-induced polyuria. The present studies examined whether induction of the COX2 isoform contributes to LiCl-induced polyuria. Four days after initiation of lithium treatment in C57 BL/6J mice, urine volume increased in LiCl-treated mice by fourfold compared with controls ( P < 0.0001) and was accompanied by decreased urine osmolality. This was temporally associated with increased renal COX2 protein expression and increased urinary PGE2 excretion, whereas COX1 levels remained unchanged. COX2 inhibition significantly blunted lithium-induced polyuria ( P < 0.0001) and reduced urinary PGE2 levels. Lithium-associated polyuria was also seen in COX1−/− mice and was associated with increased urinary PGE2. COX2 inhibition completely prevented polyuria and PGE2 excretion in COX1−/− mice, suggesting that COX2, but not COX1, plays a critical role in lithium-induced polyuria. Lithium also induced renal medullary COX2 protein expression in congenitally polyuric antidiuretic hormone (AHD)-deficient rats, demonstrating that lithium-induced COX2 protein expression is not secondary to altered ADH levels or polyuria. Lithium also decreased renal medullary GSK-3β activity, and this was temporally related to increased COX2 expression in the kidney from lithium-treated mice, consistent with a tonic in vivo suppression of COX2 expression by GSK-3 activity. In conclusion, these findings temporally link decreased GSK-3 activity to enhanced renal COX2 expression and COX2-derived urine PGE2 excretion. Suppression of COX2-derived PGE2 blunts lithium-associated polyuria.


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