Identification of a low-molecular weight TrkB antagonist with anxiolytic and antidepressant activity in mice

Neurobiology and Molecular Pharmacology, Centre de Psychiatrie et Neurosciences, UMR-894 INSERM/Université Paris Descartes, Paris, France.
The Journal of clinical investigation (Impact Factor: 13.22). 05/2011; 121(5):1846-57. DOI: 10.1172/JCI43992
Source: PubMed


The neurotrophin brain-derived neurotrophic factor (BDNF) and its receptor tropomyosin-related kinase B (TrkB) have emerged as key mediators in the pathophysiology of several mood disorders, including anxiety and depression. However, therapeutic compounds that interact with TrkB receptors have been difficult to develop. Using a combination of structure-based in silico screening and high-capacity functional assays in recombinant and neuronal cells, we identified a low-molecular weight TrkB ligand (ANA-12) that prevented activation of the receptor by BDNF with a high potency. ANA-12 showed direct and selective binding to TrkB and inhibited processes downstream of TrkB without altering TrkA and TrkC functions. KIRA-ELISA analysis demonstrated that systemic administration of ANA-12 to adult mice decreased TrkB activity in the brain without affecting neuronal survival. Mice administered ANA-12 demonstrated reduced anxiety- and depression-related behaviors on a variety of tests predictive of anxiolytic and antidepressant properties in humans. This study demonstrates that structure-based virtual screening strategy can be an efficient method for discovering potent TrkB-selective ligands that are active in vivo. We further propose that ANA-12 may be a valuable tool for studying BDNF/TrkB signaling and may constitute a lead compound for developing the next generation of therapeutic agents for the treatment of mood disorders.

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    • "Animals (n = 5) were sacrificed after 2 h of drug treatment on the 10th day. For the experiments using ANA-12 (0.5 mg/kg; i.p), a TrkB receptor antagonist [19] to verify the role of TrkB in MLT or NAS mediated signalling, following groups were used: (i) only ANA-12 group, 1% ethanol and 50% DMSO (30 min after 50% DMSO treatment) were treated for 9 days and on the 10th day, ANA-12 was injected after 30 min of 1% ethanol; (ii) NAS + ANA-12 group, NAS and 50% DMSO (30 min after NAS treatment) were injected for 9 day and ANA-12 was injected once after 30 min of NAS treatment on the 10th day; (iii) MLT + ANA-12 group, MLT and 50% DMSO (30 min after MLT treatment) were injected for 9 day and ANA-12 was injected once after 30 min of MLT treatment on the 10th day. Animals (n = 5) were sacrificed 4 h of post ANA-12 treatment on the 10th day. "
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    ABSTRACT: Though growing evidence implicates both melatonin (MLT) and its immediate precursor N -acetylserotonin (NAS) in the regulation of hippocampal neurogenesis, their comparative mechanistic relationship with core behavioural correlates of psychiatric disorders is largely unknown. To address this issue, we investigated the ability of these indoleamines to mitigate the behavioral phenotypes associated with NMDA-receptor (NMDAR) hypofunction in mice. We demonstrated that exogenous MLT and NAS treatments attenuated the NMDAR antagonist (ketamine) induced immobility in the forced swim test (FST) but not the classical striatum-related hyperlocomotor activity phenotype. The MLT/NAS-mediated protection of the phenotype in FST could be correlated to the ability of these indoleamines to counteract the deleterious effects of chronic ketamine on pro-survival molecular events by restoring the activities in MEK-ERK and PI3K-AKT pathways in the hippocampus. MLT seems to modulate these pathways by promoting accumulation of the mature form of BDNF above the control (vehicle-treated) levels, perhaps via MLT receptor-dependent mechanisms and in the process overcoming the ketamine-induced down-regulation of BDNF. In contrast, NAS appears to partly restore the ketamine-induced decrease of BDNF to the control levels. In spite of this fundamental difference in modulating BDNF levels in the upstream events, both MLT and NAS seem to overlap in the TrkB-induced downstream pro-survival mechanisms in the hippocampus, providing protection against NMDAR-hypofunction related cellular events. Perhaps, this also signifies the physiological importance of robust MLT synthesizing machinery that converts serotonin to MLT, in ensuring positive impact on hippocampus-related symptoms in psychiatric disorders.
    Behavioural brain research 10/2015; 297. DOI:10.1016/j.bbr.2015.10.027 · 3.03 Impact Factor
    • "This may have primarily been due to the inability of old-generation TrkB antagonists to cross the blood–brain barrier and remain proteolytically stable. The identification of a small-molecule TrkB antagonist, N-[2-[[(Hexahydro-2-oxo-1H-azepin-3-yl) amino] carbonyl] phenyl] benzo[b]thiophene-2-carboxamide (ANA12; Cazorla et al., 2011), that can selectively block BDNF–TrkB binding directly at the extracellular domain of TrkB receptor in a noncompetitive manner, allowed testing of the following hypotheses: (i) ANA12 will prevent the post-ischemic degradation of KCC2; and (ii) the prevention of KCC2 degradation will rescue PB resistance. "

    European Journal of Neuroscience 10/2015; DOI:10.1111/ejn.13094. · 3.18 Impact Factor
    • "In contrast, viral-induced overexpression of truncated TrkB in the NAc of rats also produces antidepressant effects in the FST [25]. Likewise, ANA-12, a selective TrkB antagonist which primarily blocks TrkB in the striatum following systemic administration, exerts antidepressant effects in the FST and tail suspension test in mice [40]. These data suggests opposite functioning of BDNF-TrkB signaling in the NAc and hippocampus with regard to depressive-like behavior. "
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    ABSTRACT: Brain-derived neurotrophic factor (BDNF) exerts antidepressant-like effects in the hippocampus and pro-depressant effects in the nucleus accumbens (NAc). It is thought that downstream signaling of the BDNF receptor TrkB mediates the effects of BDNF in these brain structures. Here, we evaluate how TrkB regulates affective behavior in the hippocampus and NAc. We overexpressed TrkB by electroporating a non-viral plasmid in the NAc or hippocampus in mice. Depression- and anxiety-like behaviors were evaluated in the sucrose test (anhedonia), the forced swim test (despair) and the elevated zero maze (anxiety). Targeted brain tissue was biochemically analyzed to identify molecular mechanisms responsible for the observed behavior. Overexpressing TrkB in the NAc increased the number of young neuronal cells and decreased despair and basal corticosterone levels. TrkB overexpression in the hippocampus increased astrocyte production and activation of the transcription factor CREB, yet without altering affective behavior. Our data suggest antidepressant effects of BDNF-TrkB in the NAc, which could not be explained by activation of the transcription factors CREB or β-catenin. The effects TrkB has on depression-related behavior in different brain regions appear to critically depend on the targeted cell type.
    Behavioural brain research 08/2015; 296. DOI:10.1016/j.bbr.2015.08.027 · 3.03 Impact Factor
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