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Synthase Kinase (synthase + kinase)
Kinds of Synthase Kinase Selected AbstractsPubertal maturation modifies the regulation of insulin-like growth factor-I receptor signaling by estradiol in the rat prefrontal cortexDEVELOPMENTAL NEUROBIOLOGY, Issue 8 2008Amaya Sanz Abstract The transition from adolescence to adulthood is accompanied by substantial plastic modifications in the cerebral cortex, including changes in the growth and retraction of neuronal processes and in the rate of synaptic formation and neuronal loss. Some of these plastic changes are prevented in female rats by prepubertal ovariectomy. The ovarian hormone estradiol modulates neuronal differentiation and survival and these effects are in part mediated by the interaction with insulin-like growth factor-I (IGF-I). In this study, we have explored whether the activation by estradiol of some components of IGF-I receptor signaling is altered in the prefrontal cortex during puberty. Estradiol administration to rats ovariectomized after puberty resulted, 24 h after the hormonal administration, in a sustained phosphorylation of Akt and glycogen synthase kinase 3, in the prefrontal cortex. However, this hormonal effect was not observed in animals ovariectomized before puberty. These findings suggest that during pubertal maturation there is a programming by ovarian hormones of the future regulatory actions of estradiol on IGF-I receptor signaling in the prefrontal cortex. The modification in the regulation of IGF-I receptor signaling by estradiol during pubertal maturation may have implications for the developmental changes occurring in the prefrontal cortex in the transition from adolescence to adulthood. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008. [source] PI3K limits TNF- , production in CD16-activated monocytesEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 2 2009Phillip R. Kramer Abstract IgG complexes bind to Fc receptor family members Fc,RI (CD64), Fc,RII (CD32) and Fc,RIII (CD16), activating cell MAPK and PI3K resulting in increased cytokine production from particular leukocytes. The signaling molecules involved in cytokine production after cross-linking CD16 have not been determined in monocytes. To address this question, TNF-,, IL-1, and IL-6 were measured in activated monocytes after inhibiting MEK1/2, PI3K and glycogen synthase kinase-, (GSK-3,). The roles of GSK-3, and NF-,B were then determined using reporter assays and siRNA treatment. The data suggested that an MAPK pathway stimulated TNF-, release but that active PI3K limited TNF-,, IL-1, and IL-6 cytokine production after cross-linking CD16. PI3K was also shown to limit nuclear translocation of NF-,B. The limiting effect of PI3K on TNF-, production from activated monocytes depended on the decrease of GSK-3, activity, which significantly reduced the transactivation of NF-,B. Moreover, the TNF-, production induced by CD16 cross-linking was reduced in monocytes after treatment with siRNA against NF-,B, implying that this transcription factor functioned in TNF-, production. The results suggest that CD16 cross-linking activated PI3K and that active PI3K limited TNF-, production by inhibiting GSK-3, activity, that blocked the action of NF-,B. [source] Mechanism of insulin-like growth factor I-mediated proliferation of adult neural progenitor cells: role of AktEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2007Haviryaji S. G. Kalluri Abstract Insulin-like growth factor I (IGF-I) is involved in the proliferation and differentiation of adult neural progenitor cells; however, the underlying mechanism is not clear. We analysed the involvement of the phosphatidylinositol 3-kinase/Akt and MEK/extracellular signal-regulated kinase (ERK) pathways in the IGF-I-mediated proliferation of rat neural progenitor cells. Stimulation of neural progenitor cells with IGF-I enhanced the phosphorylation of Akt but not ERK. Cell proliferation assay demonstrated that 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (phosphoinositide 3-kinase inhibitor) but not 1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)-butadiene (U0126) (ERK inhibitor) inhibited the IGF-I-induced survival of cells, whereas fibroblast growth factor 2 (FGF-2) enhanced the IGF-I-mediated survival of cells. Consistent with the cell proliferation assay, 5,bromo-2-deoxy-uridine incorporation studies established a negative role for IGF-I in proliferation. However, FGF-2 (ERK activator) in the presence of IGF-I (Akt activator) increased the proliferation of cells. Accordingly, stimulation of the ERK pathway by FGF-2 induced the expression of cyclin D1, which is essential for the entry of cells into cell cycle, and IGF-I in the presence of FGF-2 up-regulated the expression of cyclin D1. IGF-I in the absence or presence of FGF-2 increased the phosphorylation of glycogen synthase kinase, thus supporting its role in the survival of neural progenitor cells. To further confirm the role of ERK activation in the proliferation, we cultured cells in FGF-2 + IGF-I-containing medium in the presence and absence of U0126 (ERK inhibitor), and showed the inhibition of nestin expression in U0126-treated cells. The decrease in the cyclin D1 content in conjunction with the inhibition of nestin expression by ERK inhibitor confirms the role of ERK in the proliferation of cells. [source] Glycogen synthase kinase 3, and ,-catenin pathway is involved in toll-like receptor 4-mediated NADPH oxidase 1 expression in macrophagesFEBS JOURNAL, Issue 13 2010Jin-Sik Kim Macrophage activation contributes to the pathogenesis of atherosclerosis. In the vascular system, the major source of reactive oxygen species is the NADPH oxidase (Nox) family. Nox1 is induced by lipopolysaccharide (LPS) in macrophages, but the expression mechanism is not fully understood. We found that LPS causes ,-catenin accumulation by glycogen synthase kinase 3, (GSK3,) inactivation, and that ,-catenin accumulation increases Nox1 expression. LPS induced Nox1 mRNA expression and reactive oxygen species generation in Raw264.7 cells. Using bone marrow-derived macrophages from toll-like receptor 4 mutant mice, we also tested whether LPS-induced Nox1 expression is toll-like receptor 4 dependent. LPS caused GSK3, phosphorylation, induced ,-catenin accumulation and increased nuclear translocation. The GSK3, inhibitor LiCl potentiated LPS-induced Nox1 expression in accordance with ,-catenin accumulation and nuclear translocation. Conversely, ectopic expression of a constitutively active GSK3, mutant severely attenuated Nox1 expression. These findings identify a novel regulatory pathway controlling Nox1 expression by LPS-stimulated macrophages. [source] Wnt5a modulates glycogen synthase kinase 3 to induce phosphorylation of receptor tyrosine kinase Ror2GENES TO CELLS, Issue 11 2007Hiroyuki Yamamoto The receptor tyrosine kinase Ror2 plays important roles in mediating non-canonical Wnt5a signaling by activating the Wnt,JNK pathway and inhibiting the ,-catenin,TCF pathway. It has been shown that Ror2 is phosphorylated and activated by casein kinase I, when both molecules are over-expressed in cultured cells. However, it remains unknown whether or not Ror2 is phosphorylated upon Wnt5a stimulation. Here we show that Ror2 is phosphorylated on serine/threonine residues upon stimulation of cultured cells, expressing Ror2 endogenously, with Wnt5a, but not Wnt3a. It was found that treatment of cells with glycogen synthase kinase-3 (GSK-3) inhibitors (LiCl and SB216763) or small interfering RNAs (siRNAs) for GSK-3 (mainly GSK-3,) can inhibit Wnt5a-induced phosphorylation of Ror2. Immunoprecipitated Ror2 can also be phosphorylated by purified GSK-3, or GSK-3,in vitro, and ectopic co-expression of Ror2 and GSK-3 (mainly GSK-3,) in cultured cells results in Ror2 phosphorylation, irrespective of Wnt5a, that is sensitive to SB216763. These results indicate that GSK-3 is involved in Wnt5a-induced phosphorylation of Ror2. Moreover, it was found that Wnt5a-induced cell migration can be inhibited by SB216763 or by siRNA-mediated suppression of GSK-3, (and GSK-3,) expression, further emphasizing the role(s) of GSK-3 in Wnt5a-induced signaling. [source] Temporal lobe grey matter volume in schizophrenia is associated with a genetic polymorphism influencing glycogen synthase kinase 3-, activityGENES, BRAIN AND BEHAVIOR, Issue 4 2010F. Benedetti At the crossroad of multiple pathways regulating trophism and metabolism, glycogen synthase kinase (GSK)3 is considered a key factor in influencing the susceptibility of neurons to harmful stimuli (neuronal resilience) and is a target for several psychiatric drugs that directly inhibit it or increase its inhibitory phosphorylation. Inhibition of GSK3 prevents apoptosis and could protect against the neuropathological processes associated with psychiatric disorders. A GSK3- ,promoter single-nucleotide polymorphism (rs334558) influences transcriptional strength, and the less active form was associated with less detrimental clinical features of mood disorders. Here we studied the effect of rs334558 on grey matter volumes (voxel-based morphometry) of 57 patients affected by chronic schizophrenia. Carriers of the less active C allele variant showed significantly higher brain volumes in an area encompassing posterior regions of right middle and superior temporal gyrus, within the boundaries of Brodmann area 21. The temporal lobe is the brain parenchymal region with the most consistently documented morphometric abnormalities in schizophrenia, and neuropathological processes in these regions develop soon at the beginning of the illness. These results support the interest for GSK3- ,as a factor affecting neuropathology in major behavioural disorders, such as schizophrenia, and thus as a possible target for treatment. [source] Ischemic preconditioning of the murine liver protects through the Akt kinase pathway,HEPATOLOGY, Issue 3 2006Kunihiko Izuishi Hepatic ischemia-reperfusion (I/R) injury occurs in the settings of transplantation, trauma, and elective liver resection. Ischemic preconditioning has been used as a strategy to reduce inflammation and organ damage from I/R of the liver. However, the mechanisms involved in this process are poorly understood. We examined the role of the phosphatidylinositol 3 (PI3) kinase/Akt-signaling pathway during hepatic ischemic preconditioning (IPC). Prior to a prolonged warm ischemic insult, BALB/c mice were subjected to a 20-minute IPC period consisting of 10 minutes of ischemia and 10 minutes of reperfusion. Mice undergoing IPC demonstrated a significantly greater level and earlier activation of Akt in the liver compared with control animals. IPC also resulted in markedly less hepatocellular injury and improved survival compared with control animals. Akt activation associated with hepatic IPC suppressed the activity of several modulators of apoptosis, including Bad, glycogen synthase kinase ,, and caspase-3. In addition, IPC also inhibited the activities of c-Jun N -terminal kinase and nuclear factor ,B after I/R. Pretreatment of mice with PI3 kinase inhibitors completely abolished Akt phosphorylation and the protective effects seen with IPC. In conclusion, these results indicate that the PI3 kinase/Akt pathway plays an essential role in the protective effects of IPC in hepatic I/R injury. Modulation of this pathway may be a potential strategy in clinical settings of ischemic liver injury to decrease organ damage. Supplementary material for this article can be found on the HEPATOLOGY website (http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html). (HEPATOLOGY 2006;44:573,580.) [source] Induction of Transcriptional Activity of the Cyclic Adenosine Monophosphate Response Element Binding Protein by Parathyroid Hormone and Epidermal Growth Factor in Osteoblastic Cells,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2002John T. Swarthout Abstract Previously, we have shown that parathyroid hormone (PTH) transactivation of cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) requires both serine 129 (S129) and serine 133 (S133) in rat osteosarcoma cells UMR 106-01 (UMR) cells. Furthermore, although protein kinase A (PKA) is responsible for phosphorylation at S133, glycogen synthase kinase 3, (GSK-3,) activity is required and may be responsible for phosphorylation of CREB at S129. Here, we show, using the GAL4-CREB reporter system, that epidermal growth factor (EGF) can transactivate CREB in UMR cells in addition to PTH. Additionally, treatment of UMR cells with both PTH and EGF results in greater than additive transactivation of CREB. Furthermore, using mutational analysis we show that S129 and S133 are required for EGF-induced transcriptional activity. EGF activates members of the MAPK family including p38 and extracellular signal,activated kinases (ERKs), and treatment of UMR cells with either the p38 inhibitor (SB203580) or the MEK inhibitor (PD98059) prevents phosphorylation of CREB at S133 by EGF but not by PTH. Treatment of cells with either SB203580 or PD98059 alone or together significantly inhibits transactivation of CREB by EGF but not by PTH, indicating that EGF regulates CREB phosphorylation and transactivation through p38 and ERKs and PTH does not. Finally, the greater than additive transactivation of CREB by PTH and EGF is significantly inhibited by the PKA inhibitor H-89 or by cotreatment with SB203580 and PD98059. Thus, several different signaling pathways in osteoblastic cells can converge on and regulate CREB activity. This suggests, in vivo, that circulating agents such as PTH and EGF are acting in concert to exert their effects. [source] S100B induces tau protein hyperphosphorylation via Dickopff-1 up-regulation and disrupts the Wnt pathway in human neural stem cellsJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 3 2008Giuseppe Esposito Abstract Previous studies suggest that levels of the astrocyte-derived S100B protein, such as those occurring in brain extra-cellular spaces consequent to persistent astroglial activation, may have a pathogenetic role in Alzheimer's disease (AD). Although S100B was reported to promote , amyloid precursor protein overexpression, no clear mechanistic relationship between S100B and formation of neurofibrillary tangles (NFTs) is established. This in vitro study has been aimed at investigating whether S100B is able to disrupt Wnt pathway and lead to tau protein hyperphosphorylation. Utilizing Western blot, electrophoretic mobility shift assay, supershift and reverse transcriptase-polymerase chain reaction techniques, it has been demonstrated that micromolar S100B concentrations stimulate c-Jun N-terminal kinase (JNK) phosphorylation through the receptor for advanced glycation ending products, and subsequently activate nuclear AP-1/cJun transcription, in cultured human neural stem cells. In addition, as revealed by Western blot, small interfering RNA and immunofluorescence analysis, S100B-induced JNK activation increased expression of Dickopff-1 that, in turn, promoted glycogen synthase kinase 3, phosphorylation and ,-catenin degradation, causing canonical Wnt pathway disruption and tau protein hyperphosphorylation. These findings propose a previously unrecognized link between S100B and tau hyperphosphorylation, suggesting S100B can contribute to NFT formation in AD and in all other conditions in which neuroinflammation may have a crucial role. [source] Essential role of PSM/SH2-B variants in insulin receptor catalytic activation and the resulting cellular responsesJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2008Manchao Zhang Abstract The positive regulatory role of PSM/SH2-B downstream of various mitogenic receptor tyrosine kinases or gene disruption experiments in mice support a role of PSM in the regulation of insulin action. Here, four alternative PSM splice variants and individual functional domains were compared for their role in the regulation of specific metabolic insulin responses. We found that individual PSM variants in 3T3-L1 adipocytes potentiated insulin-mediated glucose and amino acid transport, glycogenesis, lipogenesis, and key components in the metabolic insulin response including p70 S6 kinase, glycogen synthase, glycogen synthase kinase 3 (GSK3), Akt, Cbl, and IRS-1. Highest activity was consistently observed for PSM alpha, followed by beta, delta, and gamma with decreasing activity. In contrast, dominant-negative peptide mimetics of the PSM Pro-rich, pleckstrin homology (PH), or src homology 2 (SH2) domains inhibited any tested insulin response. Potentiation of the insulin response originated at the insulin receptor (IR) kinase level by PSM variant-specific regulation of the Km (ATP) whereas the Vmax remained unaffected. IR catalytic activation was inhibited by peptide mimetics of the PSM SH2 or dimerization domain (DD). Either peptide should disrupt the complex of a PSM dimer linked to IR via SH2 domains as proposed for PSM activation of tyrosine kinase JAK2. Either peptide abolished downstream insulin responses indistinguishable from PSM siRNA knockdown. Our results implicate an essential role of the PSM variants in the activation of the IR kinase and the resulting metabolic insulin response. PSM variants act as internal IR ligands that in addition to potentiating the insulin response stimulate IR catalytic activation even in the absence of insulin. J. Cell. Biochem. 103: 162,181, 2008. © 2007 Wiley-Liss, Inc. [source] Enhanced glycogenesis is involved in cellular senescence via GSK3/GS modulationAGING CELL, Issue 6 2008Yong-Hak Seo Summary Glycogen biogenesis and its response to physiological stimuli have often been implicated in age-related diseases. However, their direct relationships to cell senescence and aging have not been clearly elucidated. Here, we report the central involvement of enhanced glycogenesis in cellular senescence. Glycogen accumulation, glycogen synthase (GS) activation, and glycogen synthase kinase 3 (GSK3) inactivation commonly occurred in diverse cellular senescence models, including the liver tissues of aging F344 rats. Subcytotoxic concentrations of GSK3 inhibitors (SB415286 and LiCl) were sufficient to induce cellular senescence with increased glycogenesis. Interestingly, the SB415286-induced glycogenesis was irreversible, as were increased levels of reactive oxygen species and gain of senescence phenotypes. Blocking GSK3 activity using siRNA or dominant negative mutant (GSK3,-K85A) also effectively induced senescence phenotypes, and GS knock-down significantly attenuated the stress-induced senescence phenotypes. Taken together, these results clearly demonstrate that augmented glycogenesis is not only common, but is also directly linked to cellular senescence and aging, suggesting GSK3 and GS as novel modulators of senescence, and providing new insight into the metabolic backgrounds of aging and aging-related pathogenesis. [source] Dual alteration of limbic dopamine D1 receptor-mediated signalling and the Akt/GSK3 pathway in dopamine D3 receptor mutants during the development of methamphetamine sensitizationJOURNAL OF NEUROCHEMISTRY, Issue 1 2007Pei-Chun Chen Abstract The central dopamine system plays significant roles in motor activity and drug-induced behavioural sensitization. Our goal was to determine the significance of dopamine D3 receptors in the development of behavioural sensitization to methamphetamine, assessed with D3 receptor mutant mice. The absence of D3 receptors significantly increased the behavioural responses to acute methamphetamine and evoked a faster rate of behavioural sensitization to chronic methamphetamine. In addition, both D3 receptor protein and mRNA levels in the limbic forebrain decreased in sensitized wild-type mice. Further analyses indicated that D1 -dependent behavioural sensitization and the number of limbic D1 receptors increased in sensitized D3 mutants as compared with sensitized wild-type mice. Consistent with this finding, we observed higher levels of D1 receptor-evoked cAMP accumulation and basal phosphoDARPP-32/Thr34 in the limbic forebrain of D3 mutants than wild-type mice and the difference was more pronounced after chronic methamphetamine treatment. We also observed an increase in phospho-extracellular signal-regulated kinase 2 but a decrease in phosphoAkt/Ser473 and phosphoglycogen synthase kinase 3 (GSK3)-,/, in the limbic forebrain of D3 mutants compared with wild-type mice after methamphetamine treatment. The convergent results implicate D3 receptors as a negative regulator of the development of methamphetamine sensitization. A compensatory up-regulation of D1 receptor-mediated signals, in addition to an altered Akt/GSK3 pathway, could contribute to the accelerated development of behavioural sensitization. [source] Deletion of tau attenuates heat shock-induced injury in cultured cortical neuronsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 1 2010Yanying Miao Abstract The microtubule-associated protein tau has been implicated in ,-amyloid- and glutamate-induced neurotoxicity. However, the potential role of tau in response to other insults to neurons remains unclear. In this study, we examined whether deletion of tau would change cell injury induced by heat shock in primary cultures of cortical neurons. After 30 min of a 45°C heat shock, lactate dehydrogenase (LDH) release increased, reaching a peak at 6 hr in wild-type (WT) neurons. A significantly lower LDH release, with a peak delayed by 24 hr, was detected in tau knockout (TKO) neurons. After heat shock treatment, MAP-2 and tubulin staining of the processes of WT neurons revealed more dramatic abnormalities than in TKO neurons. Both WT and TKO neurons exhibited a similar elevation of HSP70 level but different time courses of Akt phosphorylation. In contrast to an early, brief response in WT neurons, TKO neurons displayed a late, but long-lasting increase in phosphorylation of Akt and its downstream target, glycogen synthase kinase 3,. Additionally, inhibition of Akt activity aggravated the cell morbidity caused by heat shock exposure in both WT and TKO neurons, indicating a protective role of Akt against cell injury. In conclusion, our results demonstrate that deletion of tau attenuated heat shock-induced neuronal injury. Enhanced Akt response in the absence of endogenous tau is suggested to represent a compensatory mechanism for regulating cell reactions to stress stimuli. © 2009 Wiley-Liss, Inc. [source] ,-Amino-3-hydroxy-5-methyl-4-isoxazole propionate attenuates glutamate-induced caspase-3 cleavage via regulation of glycogen synthase kinase 3,JOURNAL OF NEUROSCIENCE RESEARCH, Issue 5 2008Takaaki Nishimoto Abstract Preconditioning of sublethal ischemia exhibits neuroprotection against subsequent ischemia-induced neuronal death. It has been indicated that glutamate, an excitatory amino acid, is involved in the pathogenesis of ischemia-induced neuronal death or neurodegeneration. To elucidate whether prestimulation of glutamate receptor could counter ischemia-induced neuronal death or neurodegeneration, we examined the effect of ,-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA), an ionotropic subtype of glutamate receptor, on excess glutamate-induced excitotoxicity using primary cortical neuronal cultures. We found that AMPA exerted a neuroprotective effect in a time- and concentration-dependent manner. A blocker of phosphatidylinositol-3 kinase (PI3K), LY294002 (10 ,M), significantly attenuated AMPA-induced protection. In addition, Ser473 of Akt/PKB, a downstream target of PI3K, was phosphorylated by AMPA administration (10 ,M). Glycogen synthase kinase 3, (GSK3,), which has been reported to be inactivated by Akt, was phosphorylated at Ser9 by AMPA. Ser9-phosphorylated GSK3, or inactivated form would be a key molecule for neuroprotection, insofar as lithium chloride (100 ,M) and SB216763 (10 ,M), inhibitors of GSK3,, also induced phosphorylation of GSK3, at Ser9 and exerted neuroprotection, respectively. Glutamate (100 ,M) increased cleaved caspase-3, an apoptosis-related cysteine protease, and caspase-3 inhibitor (Ac-DEVD-CHO; 1 ,M) blocked glutamate-induced excitotoxicity in our culture. AMPA (10 ,M, 24 hr) and SB216763 (10 ,M) prominently decreased glutamate-induced caspase-3 cleavage. These findings suggest that AMPA activates PI3K-Akt and subsequently inhibits GSK3, and that inactivated GSK3, attenuates glutamate-induced caspase-3 cleavage and neurotoxicity. © 2007 Wiley-Liss, Inc. [source] Glycogen synthase kinase 3 (GSK-3) inhibitors as new promising drugs for diabetes, neurodegeneration, cancer, and inflammationMEDICINAL RESEARCH REVIEWS, Issue 4 2002Ana Martinez Abstract Glycogen synthase kinase 3 (GSK-3) was initially described as a key enzyme involved in glycogen metabolism, but is now known to regulate a diverse array of cell functions. Two forms of the enzyme, GSK-3, and GSK-3,, have been previously identified. Small molecules inhibitors of GSK-3 may, therefore, have several therapeutic uses, including the treatment of neurodegenerative diseases, diabetes type II, bipolar disorders, stroke, cancer, and chronic inflammatory disease. As there is lot of recent literature dealing with the involvement of GSK-3 in the molecular pathways of different diseases, this review is mainly focused on the new GSK-3 inhibitors discovered or specifically developed for this enzyme, their chemical structure, synthesis, and structure,activity relationships, with the aim to provide some clues for the future optimization of these promising drugs. © 2002 Wiley Periodicals, Inc. Med Res Rev, 22, No. 4, 373,384, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/med.10011 [source] Erythropoietin plus insulin-like growth factor-I protects against neuronal damage in a murine model of human immunodeficiency virus-associated neurocognitive disordersANNALS OF NEUROLOGY, Issue 3 2010Yeon-Joo Kang PhD Objective Prolonged human immunodeficiency virus-1 (HIV-1) infection leads to neurological debilitation, including motor dysfunction and frank dementia. Although pharmacological control of HIV infection is now possible, HIV-associated neurocognitive disorders (HAND) remain intractable. Here, we report that chronic treatment with erythropoietin (EPO) and insulin-like growth factor-I (IGF-I) protects against HIV/gp120-mediated neuronal damage in culture and in vivo. Methods Initially, we tested the neuroprotective effects of various concentrations of EPO, IGF-I, or EPO+IGF-I from gp120-induced damage in vitro. To assess the chronic effects of EPO+IGF-I administration in vivo, we treated HIV/gp120-transgenic or wild-type mice transnasally once a week for 4 months and subsequently conducted immunohistochemical analyses. Results Low concentrations of EPO+IGF-I provided neuroprotection from gp120 in vitro in a synergistic fashion. In vivo, EPO+IGF-I treatment prevented gp120-mediated neuronal loss, but did not alter microgliosis or astrocytosis. Strikingly, in the brains of both humans with HAND and gp120-transgenic mice, we found evidence for hyperphosphorylated tau protein (paired helical filament-I tau), which has been associated with neuronal damage and loss. In the mouse brain following transnasal treatment with EPO+IGF-I, in addition to neuroprotection we observed increased phosphorylation/activation of Akt (protein kinase B) and increased phosphorylation/inhibition of glycogen synthase kinase (GSK)-3,, dramatically decreasing downstream hyperphosphorylation of tau. These results indicate that the peptides affected their cognate signaling pathways within the brain parenchyma. Interpretation Our findings suggest that chronic combination therapy with EPO+IGF-I provides neuroprotection in a mouse model of HAND, in part, through cooperative activation of phosphatidylinositol 3-kinase/Akt/GSK-3, signaling. This combination peptide therapy should therefore be tested in humans with HAND. ANN NEUROL 2010;68:342,352 [source] Reversing interleukin-2 inhibition mediated by anti,double-stranded DNA autoantibody ameliorates glomerulonephritis in MRL- lpr/lpr miceARTHRITIS & RHEUMATISM, Issue 8 2010Ying-Chyi Song Objective Our previous study demonstrated that anti,double-stranded DNA (anti-dsDNA) antibodies involved in lupus nephritis down-regulate the production of interleukin-2 (IL-2) in T cells, which in turn, contributes to the defective production of cytotoxic cells and to activation-induced cell death in vitro. To reveal novel molecular targets for lupus therapy, the molecular mechanisms of IL-2 down-regulation by anti-dsDNA were studied. Methods Anti-dsDNA monoclonal antibody (mAb) 9D7 was used to study the molecular mechanisms of IL-2 production in vitro. Treatment with arginine-rich peptide, a penetration inhibitor, was used to verify the effect of internalization of anti-dsDNA on the production of IL-2. The signaling pathway for IL-2 expression induced by anti-dsDNA was analyzed by using kinase inhibitors. The therapeutic effects of these inhibitors were evaluated in MRL- lpr/lpr mice. Results Inhibition of IL-2 production in activated Jurkat cells and human T cells pretreated with mAb 9D7 was reversed by treatment with the arginine-rich peptide. Levels of pAkt and phosphorylated glycogen synthase kinase 3 (pGSK-3) were reduced in activated Jurkat cells that had been pretreated with mAb 9D7. The inhibition of IL-2 production by mAb 9D7 was counteracted by pretreating the cells with LiCl (a GSK-3 inhibitor). However, IL-2 reduction was not recovered in the cells pretreated with ERK and JNK inhibitors. Furthermore, MRL- lpr/lpr mice injected with LiCl or with arginine-rich peptide restored the IL-2 production and reduced the manifestations of lupus. Conclusion These findings suggest that penetration of T cells by anti-dsDNA may inhibit IL-2 production by activating GSK-3. Moreover, blocking GSK-3 activation as well as inhibiting anti-dsDNA penetration is a potential therapeutic approach for lupus. [source] META060 inhibits osteoclastogenesis and matrix metalloproteinases in vitro and reduces bone and cartilage degradation in a mouse model of rheumatoid arthritisARTHRITIS & RHEUMATISM, Issue 6 2010Veera Reddy Konda Objective The multikinase inhibitor META060 has been shown to inhibit NF-,B activation and expression of markers of inflammation. This study was undertaken to investigate the effect of META060 on biomarkers associated with bone and cartilage degradation in vitro and its antiinflammatory efficacy in vivo in both acute and chronic inflammation models. Methods Glycogen synthase kinase 3, (GSK3,),dependent ,-catenin phosphorylation was evaluated in RAW 264.7 macrophages to assess kinase inhibition. The inhibition of osteoclastogenesis and tartrate-resistant acid phosphatase (TRAP) activity was evaluated in RANKL-treated RAW 264.7 cells. The inhibition of interleukin-1, (IL-1,),mediated markers of inflammation was analyzed in human rheumatoid arthritis synovial fibroblasts (RASFs). Mice with carrageenan-induced acute inflammation and collagen-induced arthritis (CIA) were used to assess efficacy. Results META060 inhibited the activity of kinases (spleen tyrosine kinase [Syk], Bruton's tyrosine kinase [Btk], phosphatidylinositol 3-kinase [PI 3-kinase], and GSK3) associated with RA and inhibited ,-catenin phosphorylation. META060 inhibited osteoclastogenesis, as indicated by decreased transformation of RAW 264.7 cells to osteoclasts and reduced TRAP activity, and inhibited IL-1,,activated prostaglandin E2, matrix metalloproteinase 3, IL-6, IL-8, and monocyte chemotactic protein 1 in RASFs. In mice with acute inflammation, oral administration of META060 reduced paw swelling similar to the effect of aspirin. In mice with CIA, META060 significantly reduced the arthritis index and decreased bone, joint, and cartilage degradation. Serum IL-6 concentrations in these mice were inhibited in a dose-dependent manner. Conclusion Our findings indicate that META060 reduces swelling in a model of acute inflammation and inhibits bone and cartilage destruction in a model of chronic inflammation. Its efficacy is associated with the inhibition of multiple protein kinases, including Syk, Btk, PI 3-kinase, and GSK3. These results warrant further clinical testing of META060 for its therapeutic potential in the treatment of inflammatory diseases. [source] Probing Novel 1-Aza-9-oxafluorenes as Selective GSK-3, InhibitorsCHEMMEDCHEM, Issue 1 2008Burkhardt Voigt Dr. Abstract Within the histopathology of Alzheimer's disease (AD) certain hallmarks are beeing observed. The occurance of protein deposits belong to such characteristic features. Such deposits can be found extracellular as ,-amyloid (A,) plaques and intracellular as neurofibrillary tangles (NFTs). In the search for novel AD therapeutics it became of great interest to investigate the formation of NFTs and their contribution to the AD symptomatic. NFTs consist of hyperphosphorylated tau protein. Within the phosphorylation process of tau protein two kinases are of great importance: cyclin dependent kinase 5 (cdk5) and its truncated regulatory subunit p25 and glycogen synthase kinase 3, (GSK-3,). The role of both kinases within the NFT formation process is still under debate. To better understand the pathophysiological process highly selective inhibitors of both kinases are of value. Known inhibitors lack the necessary selectivity. We developed novel 1-aza-9-oxafluo-renes as selective GSK-3, inhibitors. Structure,activity relationships of a series of 4-phenyl substituted derivatives are discussed. Variation of the 3-side chain led to selective carbonyl amide derivatives with selectivity factors of more than 100 at the tested ATP competitor concentrations. Such selectivities permit specific investigation of the role of GSK-3, within the NFT formation processes. [source] Downregulation of survival signalling pathways and increased apoptosis in the transition of pressure overload-induced cardiac hypertrophy to heart failureCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 11 2009Xiao-Mei Li Summary 1.,Transition from compensated left ventricular (LV) hypertrophy to decompensated heart failure was characterized using a pressure-overload induced model to elucidate the temporal relationship between cardiomyocyte apoptosis and survival signalling in this transition. 2.,Mice were subjected to transverse aortic constriction (TAC) or sham operation for 1,16 weeks and were studied by echocardiography, catheterization and histology. Relevant gene expression and phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, Akt and glycogen synthase kinase (GSK)-3, were determined. 3.,Transverse aortic constriction resulted in myocyte hypertrophy and fibrosis from Week 4 and a progressive increase in left ventricular (LV) dimensions and wall thicknesses with maintained contractile function by Week 12. However, a sharp decline in contractile function and elevated LV end-diastolic pressure from 12 to 16 weeks were observed after TAC, indicating functional decompensation. 4.,Following TAC, mRNA levels of atrial natriuretic peptide, B-type natriuretic peptide, ,-myosin heavy chain (MHC) and transforming growth factor-,1 were increased time dependently, whereas mRNA expression of ,-MHC, sarcoplasmic/endoplasmic reticulum calcium ATPase 2a and Bcl-2 were decreased. The ratio of Bcl-2/Bax was decreased and this was consistent with progressively increased myocyte apoptosis demonstrated by terminal deoxyribonucleotidyl transferase-mediated dUTP,digoxigenin nick end-labelling staining. Phosphorylation of ERK1/2 was increased by Week 4, but decreased thereafter. Levels of phosphorylated Akt declined from Week 8, whereas GSK3, phosphorylation increased from 1 to 8 weeks, then decreased from Week 12 after TAC. 5.,In conclusion, TAC resulted in early concentric and late eccentric hypertrophy with eventual development of LV dysfunction. This transition was temporally associated with a progressive increase in cell size, fibrosis and myocyte apoptosis. Downregulation of ERK1/2, Akt and GSK3, and enhanced cardiomyocyte apoptosis are implicated as important mechanisms in the transition from compensated hypertrophy to heart failure. [source] Control of ,-catenin/Tcf-directed transcription in medulloblastomaACTA PAEDIATRICA, Issue 2004C Raffel The ,-catenin, glycogen synthase kinase 3, (GSK-3,), and adenomatous polyposis coli (APC) gene products interact to form a network that influences the rate of cell proliferation. Medulloblastoma occurs as part of Turcot's syndrome and patients with Turcot's syndrome, who develop medulloblastomas, have been shown to harbor germline APC mutations. While APC mutations have been investigated and not identified in sporadic medulloblastomas, the status of the ,-catenin and GSK-3, genes has not been evaluated in this tumor. This study shows that 3 of 67 medulloblastomas harbor ,-catenin mutations, each of which converts a GSK-3, phosphorylation site from serine to cysteine. The ,-catenin mutation seen in the tumors was not present in matched constitutional DNA in the 2 cases where matched normal DNA was available. A loss of heterozygosity (LOH) analysis of 32 medulloblastomas with paired normal DNA samples was performed with 4 microsatellite markers flanking the GSK-3, locus; LOH with at least one marker was identified in 7 tumors. Sequencing of the remaining GSK-3, allele in these cases failed to identify any mutations. Taken together, these data suggest that activating mutations in the ,-catenin gene may be involved in the development of a subset of medulloblastomas. The GSK-3, gene does not appear to be a target for inactivation in this tumor. [source] | ||||||||||||||||