Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glycogen synthase kinase-3 (GSK3) is involved in signaling from the insulin receptor. Inhibitors of GSK3 are expected to effect lowering of plasma glucose similar to insulin, making GSK3 an attractive target for the treatment of type 2 diabetes. Herein we report the discovery of a series of potent and selective GSK3 inhibitors. Compounds 7-12 show oral activity in an in vivo model of type II diabetes, and 9 and 12 have desirable PK properties.
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PMID:Substituted 3-imidazo[1,2-a]pyridin-3-yl- 4-(1,2,3,4-tetrahydro-[1,4]diazepino-[6,7,1-hi]indol-7-yl)pyrrole-2,5-diones as highly selective and potent inhibitors of glycogen synthase kinase-3. 1526 32

Glycogen synthase kinase-3 is an unusual protein serine/threonine kinase that, unlike most of its 500-odd relatives in the genome, is active under resting conditions and is inactivated upon cell stimulation. The two mammalian isoforms, GSK-3alpha and beta, play largely overlapping roles and have been implicated in a variety of human pathologies, including Type II diabetes, Alzheimer's disease, bipolar disorder and cancer. Recently, the modes of regulation of this enzyme have been elucidated through a combination of structural and cell biological studies. A series of relatively selective small molecules have facilitated chemical manipulation of the enzyme in intact cells and tissues, and new roles for the protein kinase in embryonic stem cell differentiation and motility have emerged. Despite these advances, the therapeutic value of this enzyme as a drug target remains clouded by uncertainty over the potential of antagonists to promote tumorigenesis. This article describes the state of understanding of this intriguing enzyme, and weighs current evidence regarding whether there is a therapeutic window for amelioration of diseases in which it is implicated, in the absence of inducing new pathologies.
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PMID:Glycogen synthase kinase-3 in insulin and Wnt signalling: a double-edged sword? 1549 20

More than 40% of HIV-infected patients on highly active antiretroviral therapy (HAART) experience fat redistribution (lipodystrophy), a syndrome associated with insulin resistance primarily affecting insulin-stimulated nonoxidative glucose metabolism (NOGM(ins)). Skeletal muscle biopsies, obtained from 18 lipodystrophic nondiabetic patients (LIPO) and 18 nondiabetic patients without lipodystrophy (NONLIPO) before and during hyperinsulinemic (40 mU.m(-2).min(-1))-euglycemic clamps, were analyzed for insulin signaling effectors. All patients were on HAART. Both LIPO and NONLIPO patients were normoglycemic (4.9 +/- 0.1 and 4.8 +/- 0.1 mmol/l, respectively); however, NOGM(ins) was reduced by 49% in LIPO patients (P < 0.001). NOGM(ins) correlated positively with insulin-stimulated glycogen synthase activity (I-form, P < 0.001, n = 36). Glycogen synthase activity (I-form) correlated inversely with phosphorylation of glycogen synthase sites 2+2a (P < 0.001, n = 36) and sites 3a+b (P < 0.001, n = 36) during clamp. Incremental glycogen synthase-kinase-3alpha and -3beta phosphorylation was attenuated in LIPO patients (Ps < 0.05). Insulin-stimulated Akt Ser473 and Akt Thr308 phosphorylation was decreased in LIPO patients (P < 0.05), whereas insulin receptor substrate-1-associated phosphatidylinositol (PI) 3-kinase activity increased significantly (P < 0.001) and similarly (NS) in both groups during clamp. Thus, low glycogen synthase activity explained impaired NOGM(ins) in HIV lipodystrophy, and insulin signaling defects were downstream of PI 3-kinase at the level of Akt. These results suggest mechanisms for the insulin resistance greatly enhancing the risk of type 2 diabetes in HIV lipodystrophy.
Diabetes 2005 Dec
PMID:Skeletal muscle insulin signaling defects downstream of phosphatidylinositol 3-kinase at the level of Akt are associated with impaired nonoxidative glucose disposal in HIV lipodystrophy. 1630 64

Glycogen synthase kinase-3beta (GSK-3beta) is a serine/threonine kinase that has recently emerged as a key target for neurodegenerative diseases and diabetes. As an initial step of our lead discovery program, we developed a virtual screen to discriminate known GSK-3beta inhibitors and inactive compounds using FlexX, FlexX-Pharm, and FlexE. The maximal enrichment factor (EF = 28) suggests that our protocol identifies potential GSK-3beta inhibitors effectively from large compound collections. The effectiveness of our screening protocol was further investigated by comparative experimental and virtual high-throughput screens (HTSs) performed for the same subset of our corporate library. Enrichment factors, the significantly higher hit rate of virtual screening (12.9%) than that of the HTS (0.55%), and also the comparison of active clusters suggest that our virtual screening protocol is an effective tool in GSK-3beta-based library focusing. Head-to-head comparison of true/false positives and negatives revealed the two approaches to be complementary rather than competitive.
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PMID:Comparative virtual and experimental high-throughput screening for glycogen synthase kinase-3beta inhibitors. 1633 19

Glycogen synthase kinase (GSK)-3 has emerged as one of the most attractive therapeutic targets for the treatment of multiple neurological diseases, including Alzheimer's, stroke and bipolar disorders, as well as noninsulin-dependent diabetes mellitus and inflammation. Although the prominent role of GSK-3 in the adenomatous polyposis coli (APC)-beta-catenin destruction complex implies that inhibition of GSK-3 could possibly lead to tumor promotion through the activation of beta-catenin, several recent studies have shed new light on the activity of GSK-3 in cancer and provide insight into the molecular mechanisms by which it regulates tumor cell proliferation and survival of multiple human malignancies. In fact, GSK-3beta is a critical regulator of nuclear factor (NF)kappaB nuclear activity, suggesting that inhibition of GSK-3beta could be effective in the treatment of a wide variety of tumors with constitutively active NFkappaB. Herein, the authors will discuss the current understanding of the role of GSK-3 in human cancer and its potential as a therapeutic target.
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PMID:Targeting GSK-3: a promising approach for cancer therapy? 1655 76

Glycogen synthase kinase-3 (GSK-3) is a ubiquitously expressed serine/threonine kinase that is particularly abundant in the CNS. Dysregulation of GSK-3 activity is believed to play a key role in the pathogenesis of CNS chronic disorders such as Alzheimer's disease (AD), bipolar disorder, and Huntington's disease, and of metabolic disorders such as type II diabetes. Accordingly, GSK-3 inhibitors have been postulated as therapeutic tools for these diseases. Interestingly, pathophysiological and pharmacological regulation of GSK-3 is affected by an amplification mechanism that applies both to inhibition and activation. The possibility therefore exists that sustained inhibition or activation might persist after cessation of the initial trigger. Regarding AD, GSK-3 has been shown to accumulate in pretangle neurons. Furthermore, GSK-3 phosphorylates tau in most serine and threonine residues hyperphosphorylated in PHF (paired helical filament)-tau and GSK-3 activity contributes both to beta-amyloid production and to beta-amyloid-mediated neuronal death. In good agreement, mice with conditional overexpression of GSK-3 in forebrain neurons (Tet/GSK-3beta mice) recapitulate aspects of AD neuropathology such as tau hyperphosphorylation, apoptotic neuronal death, and reactive astrocytosis as well as spatial learning deficit. Here, we exploit the conditional system used to generate Tet/GSK-3beta mice to explore whether the biochemical, histopathological, and behavioral consequences of increased GSK-3 activity are susceptible to revert after restoration of normal GSK-3 levels. Here, we show that transgene shutdown in symptomatic mice leads to normal GSK-3 activity, normal phospho-tau levels, diminished neuronal death, and suppression of the cognitive deficit, thus further supporting the potential of GSK-3 inhibitors for AD therapeutics.
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PMID:Full reversal of Alzheimer's disease-like phenotype in a mouse model with conditional overexpression of glycogen synthase kinase-3. 1668 99

Glycogen synthase kinase-3 (GSK3) is a serine-threonine protein kinase that exists as two isozymes, GSK3alpha and GSK3beta. It plays important roles in regulating cell structure, function, and survival, and dysregulation of its function is linked to disorders such as Alzheimer's disease and type II diabetes. In resting cells, GSK3 is active and regulates the function of many downstream targets, including beta-catenin. We describe the development of a cell-based assay designed to measure the activity of GSK3 by directly measuring the accumulation of beta-catenin in Chinese hamster ovary clone K1 (CHOK1) cells. Beta-catenin levels were assessed using an antibody-based staining protocol with a luminometric readout. The assay is set up in a 96-well format. The use of GSK3 inhibitors demonstrated that this assay could be used to compare the effects of various small molecules on GSK3 inhibition in CHOK1 cells.
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PMID:A cellular assay for measuring the inhibition of glycogen synthase kinase-3 via the accumulation of beta-catenin in Chinese hamster ovary clone K1 cells. 1694 17

Glycogen synthase kinase-3 (GSK-3), a serine/threonine kinase, is a fascinating enzyme with diverse biological actions in intracellular signaling systems, making it an emerging target for diseases such as diabetes mellitus, cancer, chronic inflammation, bipolar disorders and Alzheimer's disease. It is important to inhibit GSK-3 selectively and the net effect of the GSK-3 inhibitors thus should be target specific, over other phylogenetically related kinases such as CDK-2. In the present work, we have carried out three-dimensional quantitative structure activity relationship (3D-QSAR) studies on novel class of pyrazolopyrimidine derivatives as GSK-3 inhibitors reported to have improved cellular activity. Docked conformation of the most active molecule in the series, which shows desirable interactions in the receptor, was taken as template for alignment of the molecules. Statistically significant CoMFA and CoMSIA models were generated using 49 molecules in training set. By applying leave-one-out (LOO) cross-validation study, r(cv)2 values of 0.53 and 0.48 for CoMFA and CoMSIA, respectively and non-cross-validated (r(ncv)2) values of 0.98 and 0.92 were obtained for CoMFA and CoMSIA models, respectively. The predictive ability of CoMFA and CoMSIA models was determined using a test set of 12 molecules which gave predictive correlation coefficients (r(pred)2) of 0.47 and 0.48, respectively, indicating good predictive power. Based upon the information derived from CoMFA and CoMSIA contour maps, we have identified some key features that explain the observed variance in the activity and have been used to design new pyrazolopyrimidine derivatives. The designed molecules showed better binding affinity in terms of estimated docking scores with respect to the already reported systems; hence suggesting that newly designed molecules can be more potent and selective towards GSK-3beta inhibition.
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PMID:3D-QSAR and molecular docking studies on pyrazolopyrimidine derivatives as glycogen synthase kinase-3beta inhibitors. 1701 57

Glycogen synthase kinase-3 (GSK-3) has attracted much scrutiny due to its plethora of cellular functions, novel mechanisms of regulation and its potential as a therapeutic target for several common diseases. In mammals, GSK-3 is encoded by two genes, termed GSK-3alpha and GSK-3beta, that yield related but distinct protein-serine kinases. GSK-3 is unusual in that its protein kinase activity tends to be high in resting cells and cellular stimuli, such as hormones and growth factors, result in its catalytic inactivation. Further, many of the substrate proteins of GSK-3 are functionally inhibited by phosphorylation. Thus, signals that inhibit GSK-3 often cause activation of its diverse array of target proteins. Regulation of GSK-3 is important for normal development, regulation of metabolism, neuronal growth and differentiation and modulation of cell death. Dysregulation of GSK-3 activity has been implicated in human pathologies such as neurodegenerative diseases and type-2 diabetes. In this introductory chapter we provide a primer on the modes of GSK-3 regulation and a description of the various signaling pathways and cellular processes in which GSK-3 is an active participant.
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PMID:Glycogen synthase kinase-3--an overview of an over-achieving protein kinase. 1710 May 78

Type II diabetes and its associated complications are a major health concern of the developed world. One of the hallmarks of diabetes is insulin resistance, where secreted insulin no longer has any effect on its target tissues, namely, liver, muscle, and fat. An important therapeutic strategy is to modulate blood glucose levels using pharmacological agents. Glycogen synthase kinase-3 (GSK3) is a serine-threonine protein kinase that plays important roles in regulating glucose metabolism. It is a key negative regulator of insulin action and is an important contributing factor to insulin resistance in liver, muscle, and adipose tissue. We describe the development of a cell-based assay designed to measure glucose production in rat hepatoma cell line H4IIE liver cells in response to treatment with small molecule inhibitors, including GSK3 inhibitors. The assay is set up in a 96-well format, and glucose production is assessed using a convenient fluorescence-based readout. This disease-relevant cellular assay is a valuable tool for the progression of small molecules that modulate glucose production.
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PMID:A cellular assay for measuring the modulation of glucose production in H4IIE cells. 1711 23


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