-
Stefan Berg,
Margareta Bergh,
Sven Hellberg,
Katharina Högdin,
Yvonne Lo-Alfredsson,
Peter Söderman,
Stefan von Berg,
Tatjana Weigelt,
Mats Ormö,
Yafeng Xue,
Julie Tucker,
Jan Neelissen, Eva Jerning,
Yvonne Nilsson,
Ratan Bhat
[show abstract]
[hide abstract]
ABSTRACT: Glycogen synthase kinase-3β, also called tau phosphorylating kinase, is a proline-directed serine/threonine kinase which was originally identified due to its role in glycogen metabolism. Active forms of GSK3β localize to pretangle pathology including dystrophic neuritis and neurofibrillary tangles in Alzheimer's disease (AD) brain. By using a high throughput screening (HTS) approach to search for new chemical series and cocrystallization of key analogues to guide the optimization and synthesis of our pyrazine series, we have developed highly potent and selective inhibitors showing cellular efficacy and blood-brain barrier penetrance. The inhibitors are suitable for in vivo efficacy testing and may serve as a new treatment strategy for Alzheimer's disease.
Journal of Medicinal Chemistry 04/2012; · 4.80 Impact Factor
-
Ratan Bhat,
Yafeng Xue,
Stefan Berg,
Sven Hellberg,
Mats Ormö,
Yvonne Nilsson,
Ann-Cathrin Radesäter, Eva Jerning,
Per-Olof Markgren,
Thomas Borgegård,
Martin Nylöf,
Alfredo Giménez-Cassina,
Félix Hernández,
Jose J Lucas,
Javier Díaz-Nido,
Jesús Avila
[show abstract]
[hide abstract]
ABSTRACT: Glycogen synthase kinase 3 (GSK3) is a serine/threonine kinase that has been implicated in pathological conditions such as diabetes and Alzheimer's disease. We report the characterization of a GSK3 inhibitor, AR-A014418, which inhibits GSK3 (IC50 = 104 +/- 27 nM), in an ATP-competitive manner (Ki = 38 nM). AR-A014418 does not significantly inhibit cdk2 or cdk5 (IC50 > 100 microM) or 26 other kinases demonstrating high specificity for GSK3. We report the co-crystallization of AR-A014418 with the GSK3beta protein and provide a description of the interactions within the ATP pocket, as well as an understanding of the structural basis for the selectivity of AR-A014418. AR-A014418 inhibits tau phosphorylation at a GSK3-specific site (Ser-396) in cells stably expressing human four-repeat tau protein. AR-A014418 protects N2A neuroblastoma cells against cell death mediated by inhibition of the phosphatidylinositol 3-kinase/protein kinase B survival pathway. Furthermore, AR-A014418 inhibits neurodegeneration mediated by beta-amyloid peptide in hippocampal slices. AR-A014418 may thus have important applications as a tool to elucidate the role of GSK3 in cellular signaling and possibly in Alzheimer's disease. AR-A014418 is the first compound of a family of specific inhibitors of GSK3 that does not significantly inhibit closely related kinases such as cdk2 or cdk5.
Journal of Biological Chemistry 11/2003; 278(46):45937-45. · 4.77 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In Chinese Hamster Ovary (CHO) cells expressing cloned human 5-hydroxytryptamine1A A (5-HT1A) receptors, (R)-3-N,N-dicyclobutylamino-8-fluoro-[6-3H]-3,4-dihydro-2H-1-benzopyan-5-carboxamide ([3H]NAD-299) exhibited high affinity (Kd = 0.16 nM) and labeled 34% more receptors than 8-hydroxy-2-([2,3-3H]di-n-propylamino)tetralin ([3H]8-OH-DPAT). NAD-299 behaved as a silent antagonist in [35S]GTPgammaS binding similar to N-tert-butyl-3-(4-(2-methoxyphenyl)-piperazin-1-yl)-2-phenylpropanamide (WAY-100635) and (S)-5-fluoro-8-hydroxy-2-(di-n-propylamino)tetralin ((S)UH-301). 5-HT and 5-carboxamidotryptamine (5-CT) stimulated [35S]GTPgammaS binding 2.5-fold while spiperone and methiothepin inhibited [35S]GTPgammaS binding 1.4-fold. Furthermore, NAD-299 antagonised both the 5-HT stimulated and the spiperone inhibited [35S]GTPgammaS binding to basal levels. The KiL/KiH ratios for spiperone (0.66), methiothepin (0.39), WAY-100635 (0.32), (S)UH-301 (0.94), NAD-299 (1.29), NAN-190 (1.23), (S)pindolol (5.85), ipsapirone (13.1), buspirone (24.6), (+/-)8-OH-DPAT (47.3), flesinoxan (55.8), 5-HT (200) and 5-CT (389) correlated highly significantly with the intrinsic activity obtained with [35S] GTPgammaS (r = 0.97).
Journal of Receptor and Signal Transduction Research 22(1-4):483-95. · 1.59 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: There are several inconsistencies in the literature as regards the characteristics of benzamide and butyrophenone binding to dopamine D2-like receptors. The variations observed in Bmax, Kd and Kj values have led to hypotheses, such as the existence of a specific ‘benzamide binding site’ and that dopamine D2 receptors exist in a monomer-dimer equilibrium, where benzamides are supposed to bind receptor monomers and butyrophenones receptor dimers. We have previously suggested that the discrepant results may instead be related to methodological difficulties associated with the use of very high-affinity radioligands (e.g. ligand depletion and failure to achieve equilibrium). The present study was designed to reinvestigate and critically reevaluate the binding characteristics of [3H]spiperone, [3H]nemonapride, [125I](S)-3-iodo-N-[(1-ethyl-2-pyrrolidinyl)methyl]-5,6-dimethylsalicylamide ([125I]NCQ-298) and [3H]raclopride to cloned human dopamine D2A and rat striatal dopamine D2 receptors in order to establish whether they label the same receptor population. We found that the Kd values of [3H]spiperone, [125I]NCQ-298 and [3H]nemonapride were about 20 pM and that of [3H]raclopride about 1 nM. We did not find any significant differences between the Bmax values determined with the various radioligands. Furthermore, the Ki values of spiperone and NCQ-298 (derived from cross-competition studies) for dopamine D2 receptors labelled with either [3H]spiperone or [125I]NCQ-298 were in good agreement with the corresponding Kd values. In conclusion, our results clearly demonstrate that when studied under correct experimental conditions, all four radioligands label an identical receptor population.
European Journal of Pharmacology.
