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Nature Metabolism Sep 2020Type 1 diabetes (T1D) is caused by the autoimmune destruction of pancreatic beta cells. Pluripotent stem cells can now be differentiated into beta cells, thus raising...
Type 1 diabetes (T1D) is caused by the autoimmune destruction of pancreatic beta cells. Pluripotent stem cells can now be differentiated into beta cells, thus raising the prospect of a cell replacement therapy for T1D. However, autoimmunity would rapidly destroy newly transplanted beta cells. Using a genome-scale CRISPR screen in a mouse model for T1D, we show that deleting RNLS, a genome-wide association study candidate gene for T1D, made beta cells resistant to autoimmune killing. Structure-based modelling identified the U.S. Food and Drug Administration-approved drug pargyline as a potential RNLS inhibitor. Oral pargyline treatment protected transplanted beta cells in diabetic mice, thus leading to disease reversal. Furthermore, pargyline prevented or delayed diabetes onset in several mouse models for T1D. Our results identify RNLS as a modifier of beta cell vulnerability and as a potential therapeutic target to avert beta cell loss in T1D.
Topics: Animals; Autoimmunity; CRISPR-Cas Systems; Diabetes Mellitus, Type 1; Endoplasmic Reticulum Stress; Enzyme Inhibitors; Female; Genome-Wide Association Study; Induced Pluripotent Stem Cells; Insulin-Secreting Cells; Islets of Langerhans Transplantation; Mice; Mice, Inbred C57BL; Mice, Inbred NOD; Mice, Knockout; Monoamine Oxidase; Mutation; Pargyline
PubMed: 32719542
DOI: 10.1038/s42255-020-0254-1 -
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 -
Organic & Biomolecular Chemistry Mar 2021Described herein is the first example of glycosidation of thioglycosides in the presence of palladium(ii) bromide. While the activation with PdBr2 alone was proven...
Described herein is the first example of glycosidation of thioglycosides in the presence of palladium(ii) bromide. While the activation with PdBr2 alone was proven feasible, higher yields and cleaner reactions were achieved when these glycosylations were performed in the presence of propargyl bromide as an additive. Preliminary mechanistic studies suggest that propargyl bromide assists the reaction by creating an ionizing complex, which accelerates the leaving group departure. A variety of thioglycoside donors in reactions with different glycosyl acceptors were investigated to determine the initial scope of this new reaction. Selective and chemoselective activation of thioglycosides over other leaving groups has also been explored.
Topics: Catalysis; Disaccharides; Glycosylation; Palladium; Pargyline; Thioglycosides
PubMed: 33599667
DOI: 10.1039/d1ob00004g -
Molecular Neurodegeneration Apr 2024Hypometabolism tied to mitochondrial dysfunction occurs in the aging brain and in neurodegenerative disorders, including in Alzheimer's disease, in Down syndrome, and in...
BACKGROUND
Hypometabolism tied to mitochondrial dysfunction occurs in the aging brain and in neurodegenerative disorders, including in Alzheimer's disease, in Down syndrome, and in mouse models of these conditions. We have previously shown that mitovesicles, small extracellular vesicles (EVs) of mitochondrial origin, are altered in content and abundance in multiple brain conditions characterized by mitochondrial dysfunction. However, given their recent discovery, it is yet to be explored what mitovesicles regulate and modify, both under physiological conditions and in the diseased brain. In this study, we investigated the effects of mitovesicles on synaptic function, and the molecular players involved.
METHODS
Hippocampal slices from wild-type mice were perfused with the three known types of EVs, mitovesicles, microvesicles, or exosomes, isolated from the brain of a mouse model of Down syndrome or of a diploid control and long-term potentiation (LTP) recorded. The role of the monoamine oxidases type B (MAO-B) and type A (MAO-A) in mitovesicle-driven LTP impairments was addressed by treatment of mitovesicles with the irreversible MAO inhibitors pargyline and clorgiline prior to perfusion of the hippocampal slices.
RESULTS
Mitovesicles from the brain of the Down syndrome model reduced LTP within minutes of mitovesicle addition. Mitovesicles isolated from control brains did not trigger electrophysiological effects, nor did other types of brain EVs (microvesicles and exosomes) from any genotype tested. Depleting mitovesicles of their MAO-B, but not MAO-A, activity eliminated their ability to alter LTP.
CONCLUSIONS
Mitovesicle impairment of LTP is a previously undescribed paracrine-like mechanism by which EVs modulate synaptic activity, demonstrating that mitovesicles are active participants in the propagation of cellular and functional homeostatic changes in the context of neurodegenerative disorders.
Topics: Humans; Animals; Mice; Extracellular Space; Down Syndrome; Neuronal Plasticity; Brain; Alzheimer Disease; Disease Models, Animal; Monoamine Oxidase; Mitochondrial Diseases
PubMed: 38616258
DOI: 10.1186/s13024-024-00721-z -
Current Opinion in Chemical Biology Apr 2020One of the challenges of modern inorganic chemistry is translating the potential of metal catalysts to living systems to achieve controlled non-natural transformations.... (Review)
Review
One of the challenges of modern inorganic chemistry is translating the potential of metal catalysts to living systems to achieve controlled non-natural transformations. This field poses numerous issues associated with the metal compounds biocompatibility, stability, and reactivity in complex aqueous environment. Moreover, it should be noted that although referring to 'metal catalysis', turnover has not yet been fully demonstrated in most of the examples within living systems. Nevertheless, transition metal catalysts offer an opportunity of modulating bioprocesses through reactions that are complementary to enzymes. In this context, gold complexes, both coordination and organometallic, have emerged as promising tools for bio-orthogonal transformations, endowed with excellent reactivity and selectivity, compatibility within aqueous reaction medium, fast kinetics of ligand exchange reactions, and mild reaction conditions. Thus, a number of examples of gold-templated reactions in a biologically relevant context will be presented and discussed here in relation to their potential applications in biological and medicinal chemistry.
Topics: Alkynes; Animals; Catalysis; Coordination Complexes; Cycloaddition Reaction; Fluorescent Dyes; Gold; Humans; Hydrogenation; Kinetics; Ligands; Optical Imaging; Oxidation-Reduction; Pargyline; Propylamines; Rhodamines; Substrate Specificity
PubMed: 32086166
DOI: 10.1016/j.cbpa.2019.12.007 -
Bioorganic & Medicinal Chemistry Letters Sep 2019Pyrroline-5-carboxylate reductase 1 (PYCR1) is the final enzyme involved in the biosynthesis of proline and has been found to be upregulated in various forms of cancer....
Pyrroline-5-carboxylate reductase 1 (PYCR1) is the final enzyme involved in the biosynthesis of proline and has been found to be upregulated in various forms of cancer. Due to the role of proline in maintaining the redox balance of cells and preventing apoptosis, PYCR1 is emerging as an attractive oncology target. Previous PYCR1 knockout studies led to a reduction in tumor growth. Accordingly, a small molecule inhibitor of PYCR1 could lead to new treatments for cancer, and a focused screening effort identified pargyline as a fragment-like hit. We report the design and synthesis of the first tool compounds as PYCR1 inhibitors, derived from pargyline, which were assayed to assess their ability to attenuate the production of proline. Structural activity studies have revealed the key determinants of activity, with the most potent compound (4) showing improved activity in vitro in enzyme (IC = 8.8 µM) and pathway relevant effects in cell-based assays.
Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Enzyme Inhibitors; Humans; Molecular Structure; Pargyline; Pyrroline Carboxylate Reductases; Small Molecule Libraries; Structure-Activity Relationship; delta-1-Pyrroline-5-Carboxylate Reductase
PubMed: 31362921
DOI: 10.1016/j.bmcl.2019.07.047 -
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 -
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 -
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 -
International Journal of Molecular... Nov 2022Serotonin (5-HT) plays an essential role in regulating female reproductive function in many animals. 5-HT accumulates in the mammalian ovary with the involvement of...
Serotonin (5-HT) plays an essential role in regulating female reproductive function in many animals. 5-HT accumulates in the mammalian ovary with the involvement of membrane serotonin transporter SERT and is functionally active in the oocytes of growing follicles, but shows almost no activity in follicular cells. In this study, we clarified the interplay between 5-HT membrane transport and its degradation by monoamine oxidase (MAO) in the mammalian ovary. Using pharmacologic agents and immunohistochemical staining of the cryosections of ovaries after serotonin administration in vitro, we demonstrated the activity of transport and degradation systems in ovarian follicles. The MAO inhibitor pargyline increased serotonin accumulation in the granulosa cells of growing follicles, indicating the activity of both serotonin uptake and degradation by MAO in these cells. The activity of MAO and the specificity of the membrane transport of serotonin was confirmed in primary granulosa cell culture treated with pargyline and fluoxetine. Moreover, the accumulation of serotonin is more effective in the denuded oocytes and occurs at lower concentrations than in the oocytes within the follicles. This confirms that the activity of SERT and MAO in the granulosa cells surrounding the oocytes impedes the accumulation of serotonin in the oocytes and forms a functional barrier to serotonin.
Topics: Animals; Mice; Female; Serotonin; Granulosa Cells; Ovarian Follicle; Oocytes; Monoamine Oxidase; Serotonin Plasma Membrane Transport Proteins; Pargyline; Mammals
PubMed: 36499156
DOI: 10.3390/ijms232314828