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Biomedicine & Pharmacotherapy =... Sep 2023The accumulation of mutant ataxin-3 (Atx3) in neuronal nuclear inclusions is a pathological hallmark of Machado-Joseph disease (MJD), also known as Spinocerebellar...
The accumulation of mutant ataxin-3 (Atx3) in neuronal nuclear inclusions is a pathological hallmark of Machado-Joseph disease (MJD), also known as Spinocerebellar Ataxia Type 3. Decreasing the protein aggregation burden is a possible disease-modifying strategy to tackle MJD and other neurodegenerative disorders for which only symptomatic treatments are currently available. We performed a drug repurposing screening to identify inhibitors of Atx3 aggregation with known toxicological and pharmacokinetic profiles. Interestingly, dopamine hydrochloride and other catecholamines are among the most potent inhibitors of Atx3 aggregation in vitro. Our results indicate that low micromolar concentrations of dopamine markedly delay the formation of mature amyloid fibrils of mutant Atx3 through the inhibition of the earlier oligomerization steps. Although dopamine itself does not cross the blood-brain barrier, dopamine levels in the brain can be increased by low doses of dopamine precursors and dopamine agonists commonly used to treat Parkinsonian symptoms. In agreement, treatment with levodopa ameliorated motor symptoms in a C. elegans model of MJD. These findings suggest a possible application of dopaminergic drugs to halt or reduce Atx3 accumulation in the brains of MJD patients.
Topics: Animals; Humans; Ataxin-3; Nuclear Proteins; Repressor Proteins; Dopamine; Drug Repositioning; Caenorhabditis elegans; Machado-Joseph Disease; Dopamine Agents
PubMed: 37549460
DOI: 10.1016/j.biopha.2023.115258 -
International Clinical... Sep 2021Despite the availability of evidence-based treatments for obsessive-compulsive disorder (OCD), not all patients experience sufficient benefit or are able to tolerate... (Randomized Controlled Trial)
Randomized Controlled Trial
Despite the availability of evidence-based treatments for obsessive-compulsive disorder (OCD), not all patients experience sufficient benefit or are able to tolerate them. Tolcapone is a catechol-O-methyl-transferase (COMT) enzyme inhibitor that augments cortical dopaminergic transmission. Conduct a proof of concept study to examine whether a COMT inhibitor would reduce OCD symptoms to a greater extent than placebo. We conducted a randomized, placebo-controlled, double-blind crossover trial in adults with OCD (N = 20). Participants were assessed at baseline, after 2 weeks of tolcapone, and again after 2 weeks of placebo on measures of OCD symptom severity and psychosocial functioning. There was a 1-week washout period between the 2-week treatment phases. Two weeks of tolcapone was associated with significant improvement in OCD versus two weeks of placebo (t = 2.194, P = 0.0409). The mean percentage decreases in the total Yale-Brown obsessive-compulsive scale (YBOCS) scores for the entire sample over the corresponding 2-week period were 16.4% for tolcapone and 3.6% for placebo. These data indicate that brain penetrant COMT inhibitors merit further investigation as a candidate new treatment for OCD.
Topics: Adult; Cross-Over Studies; Double-Blind Method; Humans; Obsessive-Compulsive Disorder; Tolcapone
PubMed: 34310432
DOI: 10.1097/YIC.0000000000000368 -
Cancer Medicine Jun 2017Catechol-O-methyltransferase (COMT) is an enzyme that inactivates dopamine and other catecholamines by O-methylation. Tolcapone, a drug commonly used in the treatment of...
Catechol-O-methyltransferase (COMT) is an enzyme that inactivates dopamine and other catecholamines by O-methylation. Tolcapone, a drug commonly used in the treatment of Parkinson's disease, is a potent inhibitor of COMT and previous studies indicate that Tolcapone increases the bioavailability of dopamine in cells. In this study, we demonstrate that Tolcapone kills neuroblastoma (NB) cells in preclinical models by inhibition of COMT. Treating four established NB cells lines (SMS-KCNR, SH-SY5Y, BE(2)-C, CHLA-90) and two primary NB cell lines with Tolcapone for 48 h decreased cell viability in a dose-dependent manner, with IncuCyte imaging and Western blotting indicating that cell death was due to caspase-3-mediated apoptosis. Tolcapone also increased ROS while simultaneously decreasing ATP-per-cell in NB cells. Additionally, COMT was inhibited by siRNA in NB cells and showed similar increases in apoptotic markers compared to Tolcapone. In vivo xenograft models displayed inhibition of tumor growth and a significant decrease in time-to-event in mice treated with Tolcapone compared to untreated mice. These results indicate that Tolcapone is cytotoxic to neuroblastoma cells and invite further studies into Tolcapone as a promising novel therapy for the treatment of neuroblastoma.
Topics: Animals; Antineoplastic Agents; Apoptosis; Benzophenones; Caspase 3; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Cell Line, Tumor; Cell Proliferation; Cell Survival; Female; Humans; Mice, Nude; Neuroblastoma; Nitrophenols; Oxidative Stress; Reactive Oxygen Species; Tolcapone; Tumor Cells, Cultured
PubMed: 28429453
DOI: 10.1002/cam4.1065 -
Journal of Psychopharmacology (Oxford,... Jun 2022Catechol-O-methyltransferase (COMT) regulates cortical dopaminergic transmission and prefrontal-dependent cognitive function. However, its role in other cognitive... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Catechol-O-methyltransferase (COMT) regulates cortical dopaminergic transmission and prefrontal-dependent cognitive function. However, its role in other cognitive processes, including emotional processing, is relatively unexplored. We therefore investigated the separate and interactive influences of COMT inhibition and ValMet (rs4680) genotype on performance on an emotional test battery.
METHODS
We recruited 74 healthy men homozygous for the functional COMT ValMet polymorphism. Volunteers were administered either a single 200 mg dose of the brain-penetrant COMT inhibitor tolcapone or placebo in a double-blind, randomised manner. Emotional processing was assessed using the emotional test battery, and mood was rated using visual analogue scales and the Profile of Mood States (POMS) questionnaire across the test day.
RESULTS
There were no main or interactive effects of ValMet genotype or tolcapone on any of the emotional processing measures or mood ratings.
CONCLUSIONS
Our findings suggest that, at least in healthy adult men, COMT has little or no effect on emotional processing or mood. These findings contrast with several neuroimaging studies that suggest that COMT modulates neural activity during emotional processing. Thus, further studies are required to understand how COMT impacts on the relationship between behavioural output and neural activity during emotional processing. Nevertheless, our data suggest that novel COMT inhibitors under development for treating cognitive dysfunction are unlikely to have acute off target effects on emotional behaviours.
Topics: Adult; Brain; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Cognition; Double-Blind Method; Genotype; Humans; Male; Tolcapone
PubMed: 35443830
DOI: 10.1177/02698811221089032 -
European Journal of Medicinal Chemistry Dec 2023The aggregation of wild-type transthyretin (TTR) and over 130 genetic TTR variants underlies a group of lethal disorders named TTR amyloidosis (ATTR). TTR chemical...
The aggregation of wild-type transthyretin (TTR) and over 130 genetic TTR variants underlies a group of lethal disorders named TTR amyloidosis (ATTR). TTR chemical chaperones are molecules that hold great promise to modify the course of ATTR progression. In previous studies, we combined rational design and molecular dynamics simulations to generate a series of TTR selective kinetic stabilizers displaying exceptionally high affinities. In an effort to endorse the previously developed molecules with optimal pharmacokinetic properties, we conducted structural design optimization, leading to the development of PITB. PITB binds with high affinity to TTR, effectively inhibiting tetramer dissociation and aggregation of both the wild-type protein and the two most prevalent disease-associated TTR variants. Importantly, PITB selectively binds and stabilizes TTR in plasma, outperforming tolcapone, a drug currently undergoing clinical trials for ATTR. Pharmacokinetic studies conducted on mice confirmed that PITB exhibits encouraging pharmacokinetic properties, as originally intended. Furthermore, PITB demonstrates excellent oral bioavailability and lack of toxicity. These combined attributes position PITB as a lead compound for future clinical trials as a disease-modifying therapy for ATTR.
Topics: Mice; Animals; Prealbumin; Amyloid Neuropathies, Familial; Tolcapone; Molecular Dynamics Simulation
PubMed: 37837673
DOI: 10.1016/j.ejmech.2023.115837 -
The Journal of Biological Chemistry May 2010Parkinson disease (PD) is the second most common neurodegenerative disorder after Alzheimer disease (AD). There is considerable consensus that the increased production...
Entacapone and tolcapone, two catechol O-methyltransferase inhibitors, block fibril formation of alpha-synuclein and beta-amyloid and protect against amyloid-induced toxicity.
Parkinson disease (PD) is the second most common neurodegenerative disorder after Alzheimer disease (AD). There is considerable consensus that the increased production and/or aggregation of alpha-synuclein (alpha-syn) plays a central role in the pathogenesis of PD and related synucleinopathies. Current therapeutic strategies for treating PD offer mainly transient symptomatic relief and aim at the restitution of dopamine levels to counterbalance the loss of dopaminergic neurons. Therefore, the identification and development of drug-like molecules that block alpha-synuclein aggregation and prevent the loss of dopaminergic neurons are desperately needed to treat or slow the progression of PD. Here, we show that entacapone and tolcapone are potent inhibitors of alpha-syn and beta-amyloid (Abeta) oligomerization and fibrillogenesis, and they also protect against extracellular toxicity induced by the aggregation of both proteins. Comparison of the anti-aggregation properties of entacapone and tolcapone with the effect of five other catechol-containing compounds, dopamine, pyrogallol, gallic acid, caffeic acid, and quercetin on the oligomerization and fibrillization of alpha-syn and Abeta, demonstrate that the catechol moiety is essential for the anti-amyloidogenic activity. Our findings present the first characterization of the anti-amyloidogenic properties of tolcapone and entacapone against both alpha-synuclein and Abeta42 and highlight the potential of this class of nitro-catechol compounds as anti-amyloidogenic agents. Their inhibitory properties, mode of action, and structural properties suggest that they constitute promising lead compounds for further optimization.
Topics: Amyloid beta-Peptides; Animals; Benzophenones; Catechol O-Methyltransferase Inhibitors; Catechols; Enzyme Inhibitors; Microscopy, Electron; Nitriles; Nitrophenols; Nuclear Magnetic Resonance, Biomolecular; PC12 Cells; Peptide Fragments; Rats; Tolcapone; alpha-Synuclein
PubMed: 20150427
DOI: 10.1074/jbc.M109.080390 -
Toxicology Jan 2021A human microfluidic four-cell liver acinus microphysiology system (LAMPS), was evaluated for reproducibility and robustness as a model for drug pharmacokinetics and...
A human microfluidic four-cell liver acinus microphysiology system (LAMPS), was evaluated for reproducibility and robustness as a model for drug pharmacokinetics and toxicology. The model was constructed using primary human hepatocytes or human induced pluripotent stem cell (iPSC)-derived hepatocytes and 3 human cell lines for the endothelial, Kupffer and stellate cells. The model was tested in two laboratories and demonstrated to be reproducible in terms of basal function of hepatocytes, Terfenadine metabolism, and effects of Tolcapone (88 μM), Troglitazone (150 μM), and caffeine (600 μM) over 9 days in culture. Additional experiments compared basal outputs of albumin, urea, lactate dehydrogenase (LDH) and tumor necrosis factor (TNF)α, as well as drug metabolism and toxicity in the LAMPS model, and in 2D cultures seeded with either primary hepatocytes or iPSC-hepatocytes. Further experiments to study the effects of Terfenadine (10 μM), Tolcapone (88 μM), Trovafloxacin (150 μM with or without 1 μg/mL lipopolysaccharide), Troglitazone (28 μM), Rosiglitazone (0.8 μM), Pioglitazone (3 μM), and caffeine (600 μM) were carried out over 10 days. We found that both primary human hepatocytes and iPSC-derived hepatocytes in 3D culture maintained excellent basal liver function and Terfenadine metabolism over 10 days compared the same cells in 2D cultures. In 2D, non-overlay monolayer cultures, both cell types lost hepatocyte phenotypes after 48 h. With respect to drug effects, both cell types demonstrated comparable and more human-relevant effects in LAMPS, as compared to 2D cultures. Overall, these studies show that LAMPS is a robust and reproducible in vitro liver model, comparable in performance when seeded with either primary human hepatocytes or iPSC-derived hepatocytes, and more physiologically and clinically relevant than 2D monolayer cultures.
Topics: Acinar Cells; Cell Culture Techniques; Hepatocytes; Histamine H1 Antagonists, Non-Sedating; Humans; Liver; Microfluidics; Terfenadine
PubMed: 33307106
DOI: 10.1016/j.tox.2020.152651 -
Frontiers in Neurology 2021Parkinson's disease (PD) is a common, chronic, progressive, debilitating neurodegenerative disease. The current levodopa treatment requires the addition of other drugs,...
Parkinson's disease (PD) is a common, chronic, progressive, debilitating neurodegenerative disease. The current levodopa treatment requires the addition of other drugs, such as catechol-O-methyl transferase (COMT) inhibitors, to alleviate motor fluctuations in advanced PD. Therefore, a theoretical reference for treatment is urgently needed. In this study, an appropriate search strategy was used to screen eligible studies on different drugs to treat patients with PD from the Embase, PubMed, and Cochrane Library. The publication dates were from January 1990 to June 2021. We integrated eligible randomized controlled trials, and statistical analysis was performed on three kinds of effectiveness outcomes and two types of safety outcomes. We assessed the average difference or odds ratio between each drug and placebo and summarized them as the average and 95% confidence interval (CI), respectively. In terms of efficacy, entacapone (mean difference [MD], 0.64 h; 95% CI, 0.29-1.0), opicapone (MD, 0.92 h; 95% CI, 0.35-1.5), and tolcapone (MD, 3.2 h; 95% CI, 2.1-4.2) increased patients' total ON-time compared to placebo. Tolcapone (MD, -100 mg; 95% CI -160 to -45) reduced the total daily dose of levodopa therapy. None of these three drugs was found to have statistical significance in mean change from baseline in UPDRS part III scores when compared with others. In terms of safety, tolcapone (MD, 3.8; 95% CI, 2.1-6.8), opicapone (MD, 3.7; 95% CI, 2-7.2), and entacapone (MD, 2.2; 95% CI, 1.5-3.3) increased the number of cases of dyskinesia compared to placebo. Entacapone (MD, 1.7; 95% CI, 1.3-2.2) and tolcapone (MD, 4.3; 95% CI, 1.3-15) were more likely to cause adverse events than placebo. In conclusion, opicapone showed higher efficiency and fewer safety problems in five indicators we selected when compared with the other two drugs.
PubMed: 34630283
DOI: 10.3389/fneur.2021.707723 -
Blinded potency comparison of transthyretin kinetic stabilisers by subunit exchange in human plasma.Amyloid : the International Journal of... Mar 2021Transthyretin (TTR) tetramer dissociation is rate limiting for aggregation and subunit exchange. Slowing of TTR tetramer dissociation kinetic stabiliser binding slows...
Transthyretin (TTR) tetramer dissociation is rate limiting for aggregation and subunit exchange. Slowing of TTR tetramer dissociation kinetic stabiliser binding slows cardiomyopathy progression. Quadruplicate subunit exchange comparisons of the drug candidate AG10, and the drugs tolcapone, diflunisal, and tafamidis were carried out at 1, 5, 10, 20 and 30 µM concentrations in 4 distinct pooled wild type TTR (TTRwt) human plasma samples. These experiments reveal that the concentration dependence of the efficacy of each compound at inhibiting TTR dissociation was primarily determined by the ratio between the stabiliser's dissociation constants from TTR and albumin, which competes with TTR to bind kinetic stabilisers. The best stabilisers, tafamidis (80 mg QD), AG10 (800 mg BID), and tolcapone (3 x 100 mg over 12 h), exhibit very similar kinetic stabilisation at the plasma concentrations resulting from these doses. At a 10 µM plasma concentration, AG10 is slightly more potent as a kinetic stabiliser vs. tolcapone and tafamidis (which are similar), which are substantially more potent than diflunisal. Dissociation of TTR can be limited to 10% of its normal rate at concentrations of 5.7 µM AG10, 10.3 µM tolcapone, 12.0 µM tafamidis, and 188 µM diflunisal. The potency similarities revealed by our study suggest that differences in safety, adsorption and metabolism, pharmacokinetics, and tissue distribution become important for kinetic stabiliser clinical use decisions.
Topics: Amyloid; Amyloid Neuropathies, Familial; Benzoates; Benzoxazoles; Cardiomyopathies; Diflunisal; Humans; Kinetics; Prealbumin; Protein Aggregates; Protein Binding; Protein Multimerization; Protein Subunits; Pyrazoles; Tolcapone
PubMed: 32811187
DOI: 10.1080/13506129.2020.1808783 -
Neuropsychopharmacology : Official... Jun 2018Tolcapone, a brain penetrant selective inhibitor of catechol-O-methyltransferase (COMT) devoid of psychostimulant properties, improves cognition and cortical information... (Clinical Trial)
Clinical Trial
Tolcapone, a brain penetrant selective inhibitor of catechol-O-methyltransferase (COMT) devoid of psychostimulant properties, improves cognition and cortical information processing in rested volunteers, depending on the genotype of the functional Val158Met polymorphism of COMT. The impact of this common genetic variant on behavioral and neurophysiological markers of increased sleep need after sleep loss is controversial. Here we investigated the potential usefulness of tolcapone to mitigate consequences of sleep deprivation on lapses of sustained attention, and tested the hypothesis that dopamine signaling in the prefrontal cortex (PFC) causally contributes to neurobehavioral and neurophysiological markers of sleep homeostasis in humans. We first quantified in 73 young male volunteers the impact of COMT genotype on the evolution of attentional lapses during 40 h of extended wakefulness. Subsequently, we tested in an independent group of 30 young men whether selective inhibition of COMT activity with tolcapone counteracts attentional and neurophysiological markers of elevated sleep need in a genotype-dependent manner. Neither COMT genotype nor tolcapone affected brain electrical activity in wakefulness and sleep. By contrast, COMT genotype and tolcapone modulated the sleep loss-induced impairment of vigilant attention. More specifically, Val/Met heterozygotes produced twice as many lapses after a night without sleep than Met/Met homozygotes. Unexpectedly, tolcapone further deteriorated the sleep loss-induced performance deficits when compared to placebo, particularly in Val/Met and Met/Met genotypes. The findings suggest that PFC dopaminergic tone regulates sustained attention after sleep loss according to an inverse U-shape relationship, independently of neurophysiological markers of elevated sleep need.
Topics: Attention; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Genotype; Humans; Male; Polymorphism, Single Nucleotide; Sleep Deprivation; Tolcapone; Young Adult
PubMed: 29472644
DOI: 10.1038/s41386-018-0018-8