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Cell Mar 2021It is unclear how binding of antidepressant drugs to their targets gives rise to the clinical antidepressant effect. We discovered that the transmembrane domain of...
It is unclear how binding of antidepressant drugs to their targets gives rise to the clinical antidepressant effect. We discovered that the transmembrane domain of tyrosine kinase receptor 2 (TRKB), the brain-derived neurotrophic factor (BDNF) receptor that promotes neuronal plasticity and antidepressant responses, has a cholesterol-sensing function that mediates synaptic effects of cholesterol. We then found that both typical and fast-acting antidepressants directly bind to TRKB, thereby facilitating synaptic localization of TRKB and its activation by BDNF. Extensive computational approaches including atomistic molecular dynamics simulations revealed a binding site at the transmembrane region of TRKB dimers. Mutation of the TRKB antidepressant-binding motif impaired cellular, behavioral, and plasticity-promoting responses to antidepressants in vitro and in vivo. We suggest that binding to TRKB and allosteric facilitation of BDNF signaling is the common mechanism for antidepressant action, which may explain why typical antidepressants act slowly and how molecular effects of antidepressants are translated into clinical mood recovery.
Topics: Animals; Antidepressive Agents; Binding Sites; Brain-Derived Neurotrophic Factor; Cell Line; Cholesterol; Embryo, Mammalian; Fluoxetine; Hippocampus; Humans; Mice; Models, Animal; Molecular Dynamics Simulation; Protein Domains; Rats; Receptor, trkB; Visual Cortex
PubMed: 33606976
DOI: 10.1016/j.cell.2021.01.034 -
Nature Oct 2022There is considerable interest in screening ultralarge chemical libraries for ligand discovery, both empirically and computationally. Efforts have focused on readily...
There is considerable interest in screening ultralarge chemical libraries for ligand discovery, both empirically and computationally. Efforts have focused on readily synthesizable molecules, inevitably leaving many chemotypes unexplored. Here we investigate structure-based docking of a bespoke virtual library of tetrahydropyridines-a scaffold that is poorly sampled by a general billion-molecule virtual library but is well suited to many aminergic G-protein-coupled receptors. Using three inputs, each with diverse available derivatives, a one pot C-H alkenylation, electrocyclization and reduction provides the tetrahydropyridine core with up to six sites of derivatization. Docking a virtual library of 75 million tetrahydropyridines against a model of the serotonin 5-HT receptor (5-HTR) led to the synthesis and testing of 17 initial molecules. Four of these molecules had low-micromolar activities against either the 5-HT or the 5-HT receptors. Structure-based optimization led to the 5-HTR agonists (R)-69 and (R)-70, with half-maximal effective concentration values of 41 nM and 110 nM, respectively, and unusual signalling kinetics that differ from psychedelic 5-HTR agonists. Cryo-electron microscopy structural analysis confirmed the predicted binding mode to 5-HTR. The favourable physical properties of these new agonists conferred high brain permeability, enabling mouse behavioural assays. Notably, neither had psychedelic activity, in contrast to classic 5-HTR agonists, whereas both had potent antidepressant activity in mouse models and had the same efficacy as antidepressants such as fluoxetine at as low as 1/40th of the dose. Prospects for using bespoke virtual libraries to sample pharmacologically relevant chemical space will be considered.
Topics: Animals; Mice; Antidepressive Agents; Cryoelectron Microscopy; Fluoxetine; Hallucinogens; Ligands; Pyrrolidines; Receptor, Serotonin, 5-HT2A; Small Molecule Libraries
PubMed: 36171289
DOI: 10.1038/s41586-022-05258-z -
Journal of Neuroinflammation Jan 2022Fluoxetine, a selective serotonin reuptake inhibitor, has been reported to directly bind with 5-HT receptor (5-HTR), but the precise mechanisms, whereby fluoxetine...
BACKGROUND
Fluoxetine, a selective serotonin reuptake inhibitor, has been reported to directly bind with 5-HT receptor (5-HTR), but the precise mechanisms, whereby fluoxetine confers the anti-depressive actions via 5-HTR is not fully understood. Although neuroinflammation-induced A1 astrocytes are involved in neurodegenerative diseases, the role of A1 astrocyte in the pathogenesis and treatment of major depressive disorder (MDD) remains unclear.
METHODS
Mice were subjected to chronic mild stress (CMS) for 6 weeks and subsequently treated with fluoxetine for 4 weeks. The depressive-like and anxiety-like behaviors and the activation of A1 reactive astrocyte in hippocampus and cortex of mice were measured. Primary astrocytes were stimulated with A1 cocktail (tumor necrosis factor (TNF)-α, interleukin (IL)-1α and C1q), activated (LPS) microglia-conditioned medium (MCM) or IL-6 for 24 h and the expression of A1-special and A2-special markers were determined using RT-qPCR and western blot. The role of 5-HTR in the effects of fluoxetine on A1 reactive astrocyte was measured using 5-HTR inhibitor and siRNA in vitro and AAVs in vivo. The functions of downstream signaling Gq protein and β-arrestins in the effects of fluoxetine on the activation of A1 astrocyte were determined using pharmacological inhibitor and genetic knockout, respectively.
RESULTS
In this study, we found that fluoxetine inhibited the activation of A1 reactive astrocyte and reduced the abnormal behaviors in CMS mice, as well as ameliorated A1 astrocyte reactivity under three different stimulators in primary astrocytes. We also showed that astrocytic 5-HTR was required in the inhibitory effects of fluoxetine on A1 reactive astrocyte in MDD in vivo and in vitro. We further found that the functions of fluoxetine in the activation of A1 astrocyte were independent of either Gq protein or β-arrestin1 in vitro. β-arrestin2 pathway was the downstream signaling of astrocytic 5-HTR mediated the inhibitory effects of fluoxetine on A1 astrocyte reactivity in primary astrocytes and CMS mice, as well as the improved roles of fluoxetine in behavioral impairments of CMS mice.
CONCLUSIONS
These data demonstrate that fluoxetine restricts reactive A1 astrocyte via astrocytic 5-HTR/β-arrestin2 pathway in a mouse model of MDD and provide a novel therapeutic avenue for MDD.
Topics: Animals; Astrocytes; Depressive Disorder, Major; Fluoxetine; Mice; Serotonin; beta-Arrestin 2
PubMed: 35093099
DOI: 10.1186/s12974-022-02389-y -
Neuropsychopharmacologia Hungarica : a... Mar 2020Discovery and development of the selective serotonin reuptake inhibitors mark a milestone in neuropharmacology. Drugs from this class alter the functioning of the...
Discovery and development of the selective serotonin reuptake inhibitors mark a milestone in neuropharmacology. Drugs from this class alter the functioning of the serotonin system by the potentiation of serotonin through the negative allosteric modulation of its neuronal uptake by the human serotonin transporter. Selective serotonin reuptake inhibitors show few side effects compared to those caused by traditional antidepressants and they vary in the binding interactions formed during binding. Generally, their binding involves three specific regions of the drug structures, each participating in vital interactions, such as salt bridge formation and additional hydrophobic interactions with conserved residues in the central binding site of the target protein. Side effects, however, such as the initial lack of response to treatment, or drowsiness, nausea, and sexual dysfunction occasionally may arise. Additional binding studies, furthermore, highlighted the importance of enantioselectivity in the binding of these compounds, raising concerns about the beneficial application of racemate mixtures of some of these compounds. Therefore, additional characterisation of binding and further structural improvement of this class of drugs is necessary. The recently synthesized sertraline salts, and functional derivatives of fluoxetine and citalopram show promising results in delivering antidepressant activity as well as in effectively overcoming anorexigenic side-effects in rodent models. Hence, despite certain non-desired effects associated with selective serotonin reuptake inhibitor applications, this class of drugs is considered as first-line medication in the management of major depression, and is carrying an excellent potential for the development and refinement of the currently available and novel antidepressant therapies.
Topics: Citalopram; Depression; Fluoxetine; Humans; Serotonin Plasma Membrane Transport Proteins; Selective Serotonin Reuptake Inhibitors; Sertraline
PubMed: 32329748
DOI: No ID Found -
Molecular Therapy : the Journal of the... Apr 2022Mucopolysaccharidosis type IIIA (MPS-IIIA) is an autosomal recessive disorder caused by mutations in SGSH involved in the degradation of heparan sulfate. MPS-IIIA...
Mucopolysaccharidosis type IIIA (MPS-IIIA) is an autosomal recessive disorder caused by mutations in SGSH involved in the degradation of heparan sulfate. MPS-IIIA presents severe neurological symptoms such as progressive developmental delay and cognitive decline, for which there is currently no treatment. Brain targeting represents the main challenge for therapeutics to treat MPS-IIIA, and the development of small-molecule-based treatments able to reach the CNS could be a relevant advance for therapy. Using cell-based high content imaging to survey clinically approved drugs in MPS-IIIA cells, we identified fluoxetine, a selective serotonin reuptake inhibitor. Fluoxetine increases lysosomal and autophagic functions via TFEB activation through a RagC-dependent mechanism. Mechanistically, fluoxetine increases lysosomal exocytosis in mouse embryonic fibroblasts from MPS-IIIA mice, suggesting that this process may be responsible for heparan sulfate clearance. In vivo, fluoxetine ameliorates somatic and brain pathology in a mouse model of MPS-IIIA by decreasing the accumulation of glycosaminoglycans and aggregated autophagic substrates, reducing inflammation, and slowing down cognitive deterioration. We repurposed fluoxetine for potential therapeutics to treat human MPS-IIIA disease.
Topics: Animals; Disease Models, Animal; Fibroblasts; Fluoxetine; Heparitin Sulfate; Hydrolases; Mice; Mucopolysaccharidosis III
PubMed: 35121108
DOI: 10.1016/j.ymthe.2022.01.037 -
Pharmacological Research May 2023Neuroinflammation is tightly associated with onset of depression. The nuclear receptor related 1 protein (Nurr1, also called Nr4a2), its roles in dopaminergic neurons is...
Neuroinflammation is tightly associated with onset of depression. The nuclear receptor related 1 protein (Nurr1, also called Nr4a2), its roles in dopaminergic neurons is well understood, which can alleviate inflammation. Nevertheless, potential effects of Nr4a2 on neuroinflammation associated with depression still remains unclear. Chronic lipopolysaccharides (LPS) stress induced depressive-behaviors were confirmed via behavioral tests. Differentially expressed genes were detected by using RNA-sequencing. The anterior cingulate cortex (ACC) tissues were collected for biochemical experiments. The Golgi-Cox staining and virus labeling were used to evaluate the dendritic spines. We applied fluoxetine (FLX) and amodiaquine dihydrochloride (AQ, a highly selective agonist of Nr4a2) in mice. Overexpression experiments were performed by injecting with AAV-Nr4a2-EGFP into ACC. Chemogenetic activation of CamkII neurons via injecting the hM3Dq virus. Mice treated with LPS displayed depressive- and anxiety-like behaviors. The reduction of Nr4a2 and FosB induced by LPS were rescued by pretreatment with FLX or AQ. More importantly, LPS-induced behavior deficits in mice were also alleviated via fluoxetine treatment and pharmacological activation the expression of Nr4a2. Meanwhile, enhancing the level of Nr4a2 could improve dendritic spines loss of neuron and morphological changes in microglia. Overexpression of Nr4a2 in ACC reversed the depressive- and anxiety-like behaviors caused by LPS administration. Activation of CamkII neurons in ACC could robustly increase the expression of Nr4a2 and improve LPS-induced behavior deficits. Our findings demonstrate that the Nr4a2 may regulate depressive-like behaviors via alleviating the impairment of morphology and function on microglia and CamkII neurons induced by chronic neuroinflammation.
Topics: Animals; Mice; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Depression; Fluoxetine; Gyrus Cinguli; Lipopolysaccharides; Microglia; Neuroinflammatory Diseases; Neurons; Nuclear Receptor Subfamily 4, Group A, Member 2
PubMed: 36948326
DOI: 10.1016/j.phrs.2023.106717 -
International Journal of Molecular... Mar 2022Mapping non-canonical cellular pathways affected by approved medications can accelerate drug repurposing efforts, which are crucial in situations with a global impact... (Review)
Review
Mapping non-canonical cellular pathways affected by approved medications can accelerate drug repurposing efforts, which are crucial in situations with a global impact such as the COVID-19 pandemic. Fluoxetine and fluvoxamine are well-established and widely-used antidepressive agents that act as serotonin reuptake inhibitors (SSRI-s). Interestingly, these drugs have been reported earlier to act as lysosomotropic agents, inhibitors of acid sphingomyelinase in the lysosomes, and as ligands of sigma-1 receptors, mechanisms that might be used to fight severe outcomes of COVID-19. In certain cases, these drugs were administered for selected COVID-19 patients because of their antidepressive effects, while in other cases, clinical studies were performed to assess the effect of these drugs on treating COVID-19 patients. Clinical studies produced promising data that encourage the further investigation of fluoxetine and fluvoxamine regarding their use in COVID-19. In this review, we summarize experimental data and the results of the performed clinical studies. We also provide an overview of previous knowledge on the tissue distribution of these drugs and by integrating this information with the published experimental results, we highlight the real opportunity of using these drugs in our fight against COVID-19.
Topics: Antidepressive Agents; Fluoxetine; Fluvoxamine; Humans; Pandemics; SARS-CoV-2; Selective Serotonin Reuptake Inhibitors; COVID-19 Drug Treatment
PubMed: 35409171
DOI: 10.3390/ijms23073812 -
Biomedicine & Pharmacotherapy =... Aug 2023Bladder cancer is known as one of the top ten most common cancer types worldwide and can be majorly divided into muscles invasive bladder cancer (MIBC) and non-muscles...
Bladder cancer is known as one of the top ten most common cancer types worldwide and can be majorly divided into muscles invasive bladder cancer (MIBC) and non-muscles invasive type (NMIBC). However, the prognosis of BC remains poor under standard treatment including radical cystectomy or concurrent chemoradiotherapy. Numerous studies have reported that the prognosis of BC is associated with the activation of signal transducer and activator of transcription (STAT3) and nuclear factor kappa-B (NF-κB). Fluoxetine, a well-known anti-depressant, has been reported to against various type of cancers. However, it is unclear whether fluoxetine has the capacity to inhibit BC progression by targeting STAT3 and NF-κB-mediated signaling. Here, we used cell viability, apoptosis assay, wound healing assay, invasion/migration assay, Western blotting assay, immunofluorescence staining, as well as animal experiments, to elucidate the efficacy of fluoxetine on in vitro and in vivo BC models. We found that fluoxetine may induce cytotoxicity and intrinsic/extrinsic apoptosis in BC and enhance the potential of cisplatin. Fluoxetine promoted both caspase-dependent and caspase-independent apoptosis signaling by activating caspase-3, 8, 9, apoptosis-inducing factor (AIF), and EndG. Furthermore, fluoxetine suppressed invasion and migration ability and the expression of metastasis-associated genes. Fluoxetine was also found to inactivate the phosphorylation of STAT3 (Tyr705) and NF-κB (Ser536) and suppress the nuclear translocation of NF-κB. In MB49-bearing mice, fluoxetine effectively delayed the progression of BC without inducing general toxicity. In summary, the induction of apoptosis and the inhibition of invasion triggered by fluoxetine are associated with the inactivation of STAT3 and NF-κB.
Topics: Animals; Mice; NF-kappa B; Cisplatin; Fluoxetine; Cell Line, Tumor; Urinary Bladder Neoplasms; Apoptosis; Caspases; STAT3 Transcription Factor
PubMed: 37276643
DOI: 10.1016/j.biopha.2023.114962 -
Theranostics 2022Adult hippocampal neurogenesis and synaptic plasticity are necessary for the behavioral response to the selective serotonin reuptake inhibitor (SSRI) fluoxetine, but...
Adult hippocampal neurogenesis and synaptic plasticity are necessary for the behavioral response to the selective serotonin reuptake inhibitor (SSRI) fluoxetine, but the molecular mechanisms underlying these effects are only partially understood. Anxiety and depressive-like behaviors in mice were developed by chronic mild stress (CMS) or chronic corticosterone (CORT) treatment. Pharmacological and genetic approaches were used to investigate the role of the neuronal nitric oxide synthase (nNOS)-carboxy-terminal PDZ ligand of nNOS (CAPON) interaction in behavioral and neuroplasticity effects of serotoninergic system. Molecular biological and morphological studies were performed to examine the mechanisms underlying the behavioral effects of nNOS-CAPON interaction that modulated by 5-HT1A receptor (5-HT1AR). Fluoxetine prevented chronic stress-induced nNOS-CAPON upregulation and coupling in the dentate gyrus (DG), and promoting nNOS-CAPON association weakened the anxiolytic and antidepressant effects of fluoxetine in stressed mice. The chronic fluoxetine elevated 5-HT and 5HT1AR agonist 8-OH-DPAT decreased the expression and binding of nNOS with CAPON, whereas 5-HT1AR antagonist NAN-190 had the opposite effects. Importantly, augmenting nNOS-CAPON binding neutralized 8-OH-DPAT-upregulated spine density of DG granule cells and well-characterized synaptic-related proteins, including brain-derived neurotrophic factor (BDNF) and phosphorylation of extracellular signal regulated kinase (ERK), cAMP-response element binding protein (CREB), and synapsin in the DG and abolished the anxiolytic and antidepressant-like effects of 8-OH-DPAT. In contrast, dissociation of nNOS from CAPON rescued the effects of NAN-190 on behavior and neuroplasticity. Taken together, our results indicated that fluoxetine modifies mood behaviors and hippocampal neuroplasticity by disrupting the nNOS-CAPON interaction that links postsynaptic 5-HT1AR activation.
Topics: 8-Hydroxy-2-(di-n-propylamino)tetralin; Adaptor Proteins, Signal Transducing; Animals; Anti-Anxiety Agents; Antidepressive Agents; Fluoxetine; Hippocampus; Mice; Nitric Oxide Synthase Type I
PubMed: 35664081
DOI: 10.7150/thno.70370 -
Arhiv Za Higijenu Rada I Toksikologiju Sep 2020The aim of this study was to investigate the oxidative and apoptotic potential of fluoxetine, a widely used antidepressant in Turkey and the world, and of its metabolite...
The aim of this study was to investigate the oxidative and apoptotic potential of fluoxetine, a widely used antidepressant in Turkey and the world, and of its metabolite norfluoxetine on a model non-target organism, Daphnia magna to see how exposure to this group of antidepressants (specific serotonin reuptake inhibitors) could affect the aquatic environment in which they end up. Juvenile D. magna specimens were chronically exposed to fluoxetine and norfluoxetine alone and in combination at concentrations found in the aquatic environment (0.091 and 0.011 μg/L, respectively) and to their 10-fold environmental concentrations for 21 days. Another group of 17-day-old animals were subacutely exposed to 100-fold environmental concentrations for four days. After exposure, we measured their glutathione peroxidase (GPx) and cholinesterase (ChE) activities, thiobarbituric acid-reactive substances (TBARS), and total protein content spectrophotometrically, while mitochondrial membrane potential (MMP) was analysed by fluorescence staining, and cytochrome c and ERK1/2 protein content by Western blotting. This is the first-time cytochrome c and ERK1/2 were determined at the protein level in D. magna. We also measured their carapace length, width, and caudal spine length microscopically. At environmental concentrations fluoxetine and norfluoxetine caused an increase in ChE activity and brood production. They also caused a decrease in juvenile carapace length, width, and caudal spine length and depolarised the mitochondrial membrane. At 10-fold environmental concentrations, GPx activity, lipid peroxidation levels, cytochrome c, and ERK1/2 protein levels rose. The most pronounced effect was observed in D. magna exposed to norfluoxetine. Norfluoxetine also decreased brood production. Similar effects were observed with subacute exposure to 100-fold environmental concentrations. However, total protein content decreased. All this confirms that fluoxetine and norfluoxetine have oxidative and apoptotic potential in D. magna. Daphnia spp. have a great potential to give us precious insight into the mechanisms of environmental toxicants, but there is still a long way to go before they are clarified in these organisms.
Topics: Animals; Daphnia; Fluoxetine; Oxidation-Reduction; Oxidative Stress
PubMed: 33074175
DOI: 10.2478/aiht-2020-71-3473