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The Journal of Physiological Sciences :... Oct 2022To investigate the roles of the serotonin (5-HT) transporter (SERT) and plasma membrane monoamine transporter (PMAT) in 5-HT uptake and its metabolism in the heart, we...
To investigate the roles of the serotonin (5-HT) transporter (SERT) and plasma membrane monoamine transporter (PMAT) in 5-HT uptake and its metabolism in the heart, we monitored myocardial interstitial levels of 5-HT and 5-HIAA, a metabolite of 5-HT by monoamine oxidase (MAO), in anesthetized rats using a microdialysis technique. Fluoxetine (SERT inhibitor), decynium-22 (PMAT inhibitor), or their mixture was locally administered by reverse-microdialysis for 60 min. Subsequently, pargyline (MAO inhibitor) was co-administered. Fluoxetine rapidly increased dialysate 5-HT concentration, while decynium-22 gradually increased it. The mixture induced a larger increase in dialysate 5-HT concentration compared to fluoxetine or decynium-22 alone. Fluoxetine increased dialysate 5-HIAA concentration, and this increase was abolished by pargyline. Decynium-22 and the mixture did not change dialysate 5-HIAA concentration, which were not affected by pargyline. Both SERT and PMAT regulate myocardial interstitial 5-HT levels by its uptake; however, 5-HT uptake via PMAT leads to 5-HT metabolism by MAO.
Topics: Animals; Rats; Dialysis Solutions; Fluoxetine; Hydroxyindoleacetic Acid; Membrane Transport Proteins; Monoamine Oxidase; Monoamine Oxidase Inhibitors; Pargyline; Serotonin; Heart
PubMed: 36289481
DOI: 10.1186/s12576-022-00852-2 -
Cells Aug 2022Diabetes leads to cardiomyopathy and heart failure, the leading cause of death for diabetic patients. Monoamine oxidase (MAO) inhibition in diabetic cardiomyopathy...
Diabetes leads to cardiomyopathy and heart failure, the leading cause of death for diabetic patients. Monoamine oxidase (MAO) inhibition in diabetic cardiomyopathy prevents oxidative stress, mitochondrial and endoplasmic reticulum stress and the development of diastolic dysfunction. However, it is unclear whether, in addition to the direct effects exerted on the mitochondria, MAO activity is able to post-transcriptionally regulate cardiomyocyte function and survival in diabetes. To this aim, we performed gene and miRNA expression profiling in cardiac tissue from streptozotocin-treated mice (model of type 1 diabetes (T1D)), administered with either vehicle or MAOs inhibitor pargyline for 12 weeks. We found that inhibition of MAO activity in T1D hearts leads to profound transcriptomic changes, affecting autophagy and pro-survival pathways activation. MAO activity in T1D hearts increased miR-133a-3p, -193a-3p and -27a-3p expression. These miRNAs target insulin-like growth factor receptor 1 (), growth factor receptor bound protein 10 and inositol polyphosphate 4 phosphatase type 1A, respectively, all components of the IGF1R/PI3K/AKT signaling pathway. Indeed, AKT activation was significantly downregulated in T1D hearts, whereas MAO inhibition restored the activation of this pro-survival pathway. The present study provides an important link between MAO activity, transcriptomic changes and activation of pro-survival signaling and autophagy in diabetic cardiomyopathy.
Topics: Animals; Diabetes Mellitus, Type 1; Diabetic Cardiomyopathies; Mice; MicroRNAs; Monoamine Oxidase; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; Signal Transduction
PubMed: 36078109
DOI: 10.3390/cells11172697 -
European Journal of Nuclear Medicine... Sep 2022[F]-labeled positron emission tomography (PET) radioligands permit in vivo assessment of Alzheimer's disease biomarkers, including aggregated neurofibrillary tau (NFT)...
PURPOSE
[F]-labeled positron emission tomography (PET) radioligands permit in vivo assessment of Alzheimer's disease biomarkers, including aggregated neurofibrillary tau (NFT) with [F]flortaucipir. Due to structural similarities of flortaucipir with some monoamine oxidase A (MAO-A) inhibitors, this study aimed to evaluate flortaucipir binding to MAO-A and MAO-B and any potential impact on PET interpretation.
METHODS
[F]Flortaucipir autoradiography was performed on frozen human brain tissue slices, and PET imaging was conducted in rats. Dissociation constants were determined by saturation binding, association and dissociation rates were measured by kinetic binding experiments, and IC values were determined by competition binding.
RESULTS
Under stringent wash conditions, specific [F]flortaucipir binding was observed on tau NFT-rich Alzheimer's disease tissue and not control tissue. In vivo PET experiments in rats revealed no evidence of [F]flortaucipir binding to MAO-A; pre-treatment with MAO inhibitor pargyline did not impact uptake or wash-out of [F]flortaucipir. [F]Flortaucipir bound with low nanomolar affinity to human MAO-A in a microsomal preparation in vitro but with a fast dissociation rate relative to MAO-A ligand fluoroethyl-harmol, consistent with no observed in vivo binding in rats of [F]flortaucipir to MAO-A. Direct binding of flortaucipir to human MAO-B was not detected in a microsomal preparation. A high concentration of flortaucipir (IC of 1.3 μM) was found to block binding of the MAO-B ligand safinamide to MAO-B on microsomes suggesting that, at micromolar concentrations, flortaucipir weakly binds to MAO-B in vitro.
CONCLUSION
These data suggest neither MAO-A nor MAO-B binding will contribute significantly to the PET signal in cortical target areas relevant to the interpretation of [F]flortaucipir.
Topics: Alzheimer Disease; Animals; Brain; Carbolines; Humans; Ligands; Monoamine Oxidase; Monoamine Oxidase Inhibitors; Positron-Emission Tomography; Rats; tau Proteins
PubMed: 35596745
DOI: 10.1007/s00259-022-05822-9 -
Journal of Experimental & Clinical... Feb 2022Multiple myeloma (MM) remains an incurable cancer despite advances in therapy. Therefore, the search for new targets is still essential to uncover potential treatment...
BACKGROUND
Multiple myeloma (MM) remains an incurable cancer despite advances in therapy. Therefore, the search for new targets is still essential to uncover potential treatment strategies. Metabolic changes, induced by the hypoxic bone marrow, contribute to both MM cell survival and drug resistance. Pyrroline-5-carboxylate reductase 1 and 2 (PYCR1 and PYCR2) are two mitochondrial enzymes that facilitate the last step in the glutamine-to-proline conversion. Overexpression of PYCR1 is involved in progression of several cancers, however, its' role in hematological cancers is unknown. In this study, we investigated whether PYCR affects MM viability, proliferation and response to bortezomib.
METHODS
Correlation of PYCR1/2 with overall survival was investigated in the MMRF CoMMpass trial (653 patients). OPM-2 and RPMI-8226 MM cell lines were used to perform in vitro experiments. RPMI-8226 cells were supplemented with C-glutamine for 48 h in both normoxia and hypoxia (< 1% O, by chamber) to perform a tracer study. PYCR1 was inhibited by siRNA or the small molecule inhibitor pargyline. Apoptosis was measured using Annexin V and 7-AAD staining, viability by CellTiterGlo assay and proliferation by BrdU incorporation. Differential protein expression was evaluated using Western Blot. The SUnSET method was used to measure protein synthesis. All in vitro experiments were performed in hypoxic conditions.
RESULTS
We found that PYCR1 and PYCR2 mRNA expression correlated with an inferior overall survival. MM cells from relapsed/refractory patients express significantly higher levels of PYCR1 mRNA. In line with the strong expression of PYCR1, we performed a tracer study in RPMI-8226 cells, which revealed an increased conversion of C-glutamine to proline in hypoxia. PYCR1 inhibition reduced MM viability and proliferation and increased apoptosis. Mechanistically, we found that PYCR1 silencing reduced protein levels of p-PRAS40, p-mTOR, p-p70, p-S6, p-4EBP1 and p-eIF4E levels, suggesting a decrease in protein synthesis, which we also confirmed in vitro. Pargyline and siPYCR1 increased bortezomib-mediated apoptosis. Finally, combination therapy of pargyline with bortezomib reduced viability in CD138 MM cells and reduced tumor burden in the murine 5TGM1 model compared to single agents.
CONCLUSIONS
This study identifies PYCR1 as a novel target in bortezomib-based combination therapies for MM.
Topics: Animals; Antineoplastic Agents; Bortezomib; Cell Proliferation; Humans; Mice; Multiple Myeloma; Protein Synthesis Inhibitors; Pyrroline Carboxylate Reductases; Survival Analysis
PubMed: 35105345
DOI: 10.1186/s13046-022-02250-3 -
World Journal of Diabetes Jan 2022When combined with vanadium salts, catecholamines strongly activate glucose uptake in rat and mouse adipocytes.
BACKGROUND
When combined with vanadium salts, catecholamines strongly activate glucose uptake in rat and mouse adipocytes.
AIM
To test whether catecholamines activate glucose transport in human adipocytes.
METHODS
The uptake of 2-deoxyglucose (2-DG) was measured in adipocytes isolated from pieces of abdominal subcutaneous tissue removed from women undergoing reconstructive surgery. Pharmacological approaches with amine oxidase inhibitors, adrenoreceptor agonists and antioxidants were performed to unravel the mechanisms of action of noradrenaline or adrenaline (also named epinephrine).
RESULTS
In human adipocytes, 45-min incubation with 100 µmol/L adrenaline or noradrenaline activated 2-DG uptake up to more than one-third of the maximal response to insulin. This stimulation was not reproduced with millimolar doses of dopamine or serotonin and was not enhanced by addition of vanadate to the incubation medium. Among various natural amines and adrenergic agonists tested, no other molecule was more efficient than adrenaline and noradrenaline in stimulating 2-DG uptake. The effect of the catecholamines was not impaired by pargyline and semicarbazide, contrarily to that of benzylamine or methylamine, which are recognized substrates of semicarbazide-sensitive amine oxidase. Hydrogen peroxide at 1 mmol/L activated hexose uptake but not pyrocatechol or benzoquinone, and only the former was potentiated by vanadate. Catalase and the phosphoinositide 3-kinase inhibitor wortmannin inhibited adrenaline-induced activation of 2-DG uptake.
CONCLUSION
High doses of catecholamines exert insulin-like actions on glucose transport in human adipocytes. At submillimolar doses, vanadium did not enhance this catecholamine activation of glucose transport. Consequently, this dismantles our previous suggestion to combine the metal ion with catecholamines to improve the benefit/risk ratio of vanadium-based antidiabetic approaches.
PubMed: 35070058
DOI: 10.4239/wjd.v13.i1.37 -
ACS Pharmacology & Translational Science Dec 2021Lysine-specific demethylase 1 (LSD1 or KDM1A) is a chromatin modifying enzyme playing a key role in the cell cycle and cell differentiation and proliferation through the...
Lysine-specific demethylase 1 (LSD1 or KDM1A) is a chromatin modifying enzyme playing a key role in the cell cycle and cell differentiation and proliferation through the demethylation of histones and nonhistone substrates. In addition to its enzymatic activity, LSD1 plays a fundamental scaffolding role as part of transcription silencing complexes such as rest co-repressor (CoREST) and nucleosome remodeling and deacetylase (NuRD). A host of classical amine oxidase inhibitors such as tranylcypromine, pargyline, and phenelzine together with LSD1 tool compounds such as SP-2509 and GSK-LSD1 have been extensively utilized in LSD1 mechanistic cancer studies. Additionally, several optimized new chemical entities have reached clinical trials in oncology such as ORY-1001 (iadademstat), GSK2879552, SP-2577 (seclidemstat), IMG-7289 (bomedemstat), INCB059872, and CC-90011 (pulrodemstat). Despite this, no single study exists that characterizes them all under the same experimental conditions, preventing a clear interpretation of published results. Herein, we characterize the whole LSD1 small molecule compound class as inhibitors of LSD1 catalytic activity, disruptors of SNAIL/GFI1 (SNAG)-scaffolding protein-protein interactions, inducers of cell differentiation, and potential anticancer treatments for hematological and solid tumors to yield an updated, unified perspective of this field. Our results highlight significant differences in potency and selectivity among the clinical compounds with iadademstat being the most potent and reveal that most of the tool compounds have very low activity and selectivity, suggesting some conclusions derived from their use should be taken with caution.
PubMed: 34927013
DOI: 10.1021/acsptsci.1c00223 -
International Journal of Molecular... Nov 2021The mechanisms of resistance to antidepressant drugs is a key and still unresolved problem of psychopharmacology. Serotonin (5-HT) and brain-derived neurotrophic factor...
The mechanisms of resistance to antidepressant drugs is a key and still unresolved problem of psychopharmacology. Serotonin (5-HT) and brain-derived neurotrophic factor (BDNF) play a key role in the therapeutic effect of many antidepressants. Tryptophan hydroxylase 2 (TPH2) is the rate-limiting enzyme in 5-HT synthesis in the brain. We used zebrafish () as a promising model organism in order to elucidate the effect of TPH2 deficiency caused by p-chlorophenylalanine (pCPA) on the alterations in behavior and expression of 5-HT-related (, , , , ) and BDNF-related (, , , ) genes in the brain after prolonged treatment with two antidepressants, inhibitors of 5-HT reuptake (fluoxetine) and oxidation (pargyline). In one experiment, zebrafish were treated for 72 h with 0.2 mg/L fluoxetine, 2 mg/L pCPA, or the drugs combination. In another experiment, zebrafish were treated for 72 h with 0.5 mg/L pargyline, 2 mg/L pCPA, or the drugs combination. Behavior was studied in the novel tank diving test, mRNA levels were assayed by qPCR, 5-HT and its metabolite concentrations were measured by HPLC. The effects of interaction between pCPA and the drugs on zebrafish behavior were observed: pCPA attenuated "surface dwelling" induced by the drugs. Fluoxetine decreased mRNA levels of and genes, while pargyline decreased mRNA levels of and genes. Pargyline reduced , and genes mRNA concentration only in the zebrafish treated with pCPA. The results show that the disruption of the TPH2 function can cause a refractory to antidepressant treatment.
Topics: Animals; Antidepressive Agents; Behavior, Animal; Brain; Brain-Derived Neurotrophic Factor; Disease Models, Animal; Fluoxetine; Monoamine Oxidase Inhibitors; Pargyline; Serotonin; Selective Serotonin Reuptake Inhibitors; Tryptophan Hydroxylase; Zebrafish; Zebrafish Proteins
PubMed: 34884655
DOI: 10.3390/ijms222312851 -
Molecules (Basel, Switzerland) Oct 2021A small series of nitro group-bearing enamides was designed, synthesized (-), and evaluated for their inhibitory profiles of monoamine oxidases (MAOs) and β-site...
A small series of nitro group-bearing enamides was designed, synthesized (-), and evaluated for their inhibitory profiles of monoamine oxidases (MAOs) and β-site amyloid precursor protein cleaving enzyme 1 (β-secretase, BACE1). Compounds and exhibited a more potent MAO-B inhibition (IC value = 0.0092 and 0.016 µM, respectively) than the standards (IC value = 0.11 and 0.14 µM, respectively, for lazabemide and pargyline). Moreover, and showed greater selectivity index (SI) values toward MAO-B over MAO-A (SI of >1652.2 and >2500.0, respectively). The inhibition and kinetics studies suggested that and are reversible and competitive inhibitors with K values of 0.013 ± 0.005 and 0.0049 ± 0.0002 µM, respectively, for MAO-B. In addition, both and showed efficient BACE1 inhibitions with IC values of 8.02 ± 0.13 and 8.21 ± 0.03 µM better than the standard quercetin value (13.40 ± 0.04 µM). The parallel artificial membrane permeability assay (PAMPA) method demonstrated that all the synthesized derivatives can cross the blood-brain barrier (BBB) successfully. Docking analyses were performed by employing an induced-fit docking approach in the GLIDE module of Schrodinger, and the results were in agreement with their in vitro inhibitory activities. The present study resulted in the discovery of potent dual inhibitors toward MAO-B and BACE1, and these lead compounds can be fruitfully explored for the generation of newer, clinically active agents for the treatment of neurodegenerative disorders.
Topics: Amides; Amyloid Precursor Protein Secretases; Blood-Brain Barrier; Membranes, Artificial; Molecular Structure; Monoamine Oxidase; Monoamine Oxidase Inhibitors; Protease Inhibitors
PubMed: 34641548
DOI: 10.3390/molecules26196004 -
Molekuliarnaia Biologiia 2021Fundamental neurophysiological processes are often studied using Danio rerio fish as a model. A selective inhibitor of striatal-enriched protein tyrosine phosphatase...
Fundamental neurophysiological processes are often studied using Danio rerio fish as a model. A selective inhibitor of striatal-enriched protein tyrosine phosphatase (STEP) reduces serotonin metabolism in the D. rerio brain. Both STEP and serotonin are involved in the development of neurodegenerative behavioral disorders. Reduction or elevation of the serotonin level in the brain of mice caused by the administration of p-chlorophenylalanine or pargyline, respectively, results in a decrease in the level of ptpn5 mRNA in the striatum, ptpn5 being the gene encoding STEP. However, it has not been established whether this occurs in other organisms. We studied the effect of inhibitors of synthesis (p-chlorophenylalanine) and degradation (pargyline) of serotonin on the expression of the ptpn5 gene and the activity of STEP in the brain of D. rerio. The fish were placed in water containing p-chlorophenylalanine (2 mg/L) or pargyline (0.5 mg/L) for 72 hours, and control subjects were kept in aquarium water. The p-chlorophenylalanine treatment decreased the serotonin level in the brain fourfold, whereas pargyline increased the level of this transmitter sixfold. Both p-chlorophenylalanine and pargyline decrease STEP activity in the D. rerio brain, without affecting the level of the ptpn5 mRNA gene. Thus, interaction between STEP and the serotonin system is observed in both mammals and fish, which indicates the similarity of the regulation processes in vertebrates.
Topics: Animals; Brain; Fenclonine; Mice; Pargyline; Protein Tyrosine Phosphatases; Zebrafish
PubMed: 34432783
DOI: 10.31857/S0026898421030113 -
ACS Chemical Biology Sep 2021Ubiquitin activity-based probes have proven invaluable in elucidating structural mechanisms in the ubiquitin system by stabilizing transient macromolecular complexes of...
Ubiquitin activity-based probes have proven invaluable in elucidating structural mechanisms in the ubiquitin system by stabilizing transient macromolecular complexes of deubiquitinases, ubiquitin-activating enzymes, and the assemblies of ubiquitin-conjugating enzymes with ubiquitin ligases of the RING-Between-RING and RING-Cysteine-Relay families. Here, we demonstrate that an activity-based probe, ubiquitin-propargylamine, allows for the preparative reconstitution and structural analysis of the interactions between ubiquitin and certain HECT ligases. We present a crystal structure of the ubiquitin-linked HECT domain of HUWE1 that defines a catalytically critical conformation of the C-terminal tail of the ligase for the transfer of ubiquitin to an acceptor protein. Moreover, we observe that ubiquitin-propargylamine displays selectivity among HECT domains, thus corroborating the notion that activity-based probes may provide entry points for the development of specific, active site-directed inhibitors and reporters of HECT ligase activities.
Topics: Amino Acid Sequence; Catalysis; Catalytic Domain; Cysteine; Humans; Models, Molecular; Pargyline; Propylamines; Protein Conformation; Structure-Activity Relationship; Substrate Specificity; Ubiquitin; Ubiquitin-Conjugating Enzymes; Ubiquitin-Protein Ligases; Ubiquitination
PubMed: 34403242
DOI: 10.1021/acschembio.1c00433