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Clinical and Translational Medicine Jul 2024Serotonin (5-hydroxytryptamine) is a multifunctional bioamine serving as a neurotransmitter, peripheral hormone and mitogen in the vertebrate system. It has pleiotropic... (Review)
Review
BACKGROUND
Serotonin (5-hydroxytryptamine) is a multifunctional bioamine serving as a neurotransmitter, peripheral hormone and mitogen in the vertebrate system. It has pleiotropic activities in central nervous system and gastrointestinal function via an orchestrated action of serotonergic elements, particularly serotonin receptor-mediated signalling cascades. The mitogenic properties of serotonin have garnered recognition for years and have been exploited for repurposing serotonergic-targeted drugs in cancer therapy. However, emerging conflicting findings necessitate a more comprehensive elucidation of serotonin's role in cancer pathogenesis.
MAIN BODY AND CONCLUSION
Here, we provide an overview of the biosynthesis, metabolism and action modes of serotonin. We summarise our current knowledge regarding the effects of the peripheral serotonergic system on tumourigenesis, with a specific emphasis on its immunomodulatory activities in human cancers. We also discuss the dual roles of serotonin in tumour pathogenesis and elucidate the potential of serotonergic drugs, some of which display favourable safety profiles and impressive efficacy in clinical trials, as a promising avenue in cancer treatment.
KEY POINTS
Primary synthesis and metabolic routes of peripheral 5-hydroxytryptamine in the gastrointestinal tract. Advanced research has established a strong association between the serotonergic components and carcinogenic mechanisms. The interplay between serotonergic signalling and the immune system within the tumour microenvironment orchestrates antitumour immune responses. Serotonergic-targeted drugs offer valuable clinical options for cancer therapy.
Topics: Humans; Serotonin; Neoplasms; Signal Transduction
PubMed: 38943041
DOI: 10.1002/ctm2.1750 -
Science Advances Jun 2024Declined memory is a hallmark of Alzheimer's disease (AD). Experiments in rodents and human postmortem studies suggest that serotonin (5-hydroxytryptamine, 5-HT) plays a...
Declined memory is a hallmark of Alzheimer's disease (AD). Experiments in rodents and human postmortem studies suggest that serotonin (5-hydroxytryptamine, 5-HT) plays a role in memory, but the underlying mechanisms are unknown. Here, we investigate the role of 5-HT 2C receptor (5-HTR) in regulating memory. Transgenic mice expressing a humanized mutation exhibit impaired plasticity of hippocampal ventral CA1 (vCA1) neurons and reduced memory. Further, 5-HT neurons project to and synapse onto vCA1 neurons. Disruption of 5-HT synthesis in vCA1-projecting neurons or deletion of 5-HTRs in the vCA1 impairs neural plasticity and memory. We show that a selective 5-HTR agonist, lorcaserin, improves synaptic plasticity and memory in an AD mouse model. Cumulatively, we demonstrate that hippocampal 5-HTR signaling regulates memory, which may inform the use of 5-HTR agonists in the treatment of dementia.
Topics: Animals; Humans; Receptor, Serotonin, 5-HT2C; Memory; Mice; Mice, Transgenic; Neuronal Plasticity; Alzheimer Disease; Hippocampus; Serotonin; Disease Models, Animal; CA1 Region, Hippocampal; Neurons; Serotonin 5-HT2 Receptor Agonists
PubMed: 38941473
DOI: 10.1126/sciadv.adl2675 -
European Journal of Medicinal Chemistry Jun 2024The serotonin type 6 receptor (5-HTR) displays a strong constitutive activity, suggesting it participates largely in the physiological and pathological processes...
The serotonin type 6 receptor (5-HTR) displays a strong constitutive activity, suggesting it participates largely in the physiological and pathological processes controlled by the receptor. The active states of 5-HTR engage particular signal transduction pathways that lead to different biological responses. In this study, we present the development of 5-HTR neutral antagonists at Gs signaling built upon the 2-phenylpyrrole scaffold. Using molecular dynamics simulations, we outline the relationship between the exposure of the basic center of the molecules and their ability to target the agonist-activated state of the receptor. Our study identifies compound 30 as a potent and selective neutral antagonist at 5-HTR-operated Gs signaling. Furthermore, we demonstrate the cytoprotective effects of 30 and structurally diverse 5-HTR neutral antagonists at Gs signaling in C8-D1A cells and human astrocytes exposed to rotenone. This effect is not observed for 5-HTR agonists or inverse agonists. In light of these findings, we propose compound 30 as a valuable molecular probe to study the biological effects associated with the agonist-activated state of 5-HTR and provide insight into the glioprotective properties of 5-HTR neutral antagonists at Gs signaling.
PubMed: 38936149
DOI: 10.1016/j.ejmech.2024.116615 -
Pharmaceuticals (Basel, Switzerland) Jun 2024The heterogeneity of etiology may serve as a crucial factor in the challenges of treatment, including the low response rate and the delay in establishing therapeutic...
The heterogeneity of etiology may serve as a crucial factor in the challenges of treatment, including the low response rate and the delay in establishing therapeutic effect. In the present study, we examined whether social experience since early life is one of the etiologies, with the involvement of the 5-HT1A receptors, and explored the potentially therapeutic action of the subchronic administration of buspirone, a partial 5-HT1A agonist. Rats were isolation reared (IR) since their weaning, and the depressive profile indexed by the forced-swim test (FST) was examined in adulthood. Nonspecific locomotor activity was used for the IR validation. Buspirone administration (1 mg/kg/day) was introduced for 14 days (week 9-11). The immobility score of the FST was examined before and after the buspirone administration. Tissue levels of serotonin (5-HT) and its metabolite 5-HIAA were measured in the hippocampus, the amygdala, and the prefrontal cortex. Efflux levels of 5-HT, dopamine (DA), and norepinephrine (NE) were detected in the hippocampus by brain dialysis. Finally, the full 5-HT1A agonist 8-OH-DPAT (0.5 mg/kg) was acutely administered in both behavioral testing and the dialysis experiment. Our results showed (i) increased immobility time in the FST for the IR rats as compared to the social controls, which could not be reversed by the buspirone administration; (ii) IR-induced FST immobility in rats receiving buspirone was corrected by the 8-OH-DPAT; and (iii) IR-induced reduction in hippocampal 5-HT levels can be reversed by the buspirone administration. Our data indicated the 5-HT1A receptor-linked early life social experience as one of the mechanisms of later life depressive mood.
PubMed: 38931384
DOI: 10.3390/ph17060717 -
Pharmaceuticals (Basel, Switzerland) May 2024Serotonin (5-hydroxytryptamine, 5-HT) is a neurotransmitter regulating numerous physiological functions, and its dysregulation is a crucial component of the pathological... (Review)
Review
Serotonin (5-hydroxytryptamine, 5-HT) is a neurotransmitter regulating numerous physiological functions, and its dysregulation is a crucial component of the pathological processes of schizophrenia, depression, migraines, and obesity. 5-HT interacts with 14 different receptors, of which 5-HTRs, 5-HTRs, and 5-HTRs are G protein-coupled receptors (GPCRs), while 5-HTR is a ligand-gated ion channel. Over the years, selective orthosteric ligands have been identified for almost all serotonin receptors, yielding several clinically relevant drugs. However, the high degree of homology between 5-HTRs and other GPCRs means that orthosteric ligands can have severe side effects. Thus, there has recently been increased interest in developing safer ligands of GPCRs, which bind to less conserved, more specific sites, distinct from that of the receptor's natural ligand. The present review describes the identification of allosteric ligands of serotonin receptors, which are largely natural compounds (oleamide, cannabidiol, THC, and aporphine alkaloids), complemented by synthetic modulators developed in large part for the 5-HT receptor. The latter are positive allosteric modulators sought after for their potential as drugs preferable over the orthosteric agonists as antiobesity agents for their potentially safer profile. When available, details on the interactions between the ligand and allosteric binding site will be provided. An outlook on future research in the field will also be provided.
PubMed: 38931362
DOI: 10.3390/ph17060695 -
Plants (Basel, Switzerland) Jun 2024Blueberries ( L.) are cultivated worldwide and are among the best dietary sources of bioactive compounds with beneficial health effects. This study aimed to investigate...
Chemical Composition, Antioxidant Activities, Antidepressant Effect, and Lipid Peroxidation of Peruvian Blueberry: Molecular Docking Studies on Targets Involved in Oxidative Stress and Depression.
Blueberries ( L.) are cultivated worldwide and are among the best dietary sources of bioactive compounds with beneficial health effects. This study aimed to investigate the components of Peruvian blueberry using high-performance liquid chromatography coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS/MS), identifying 11 compounds. Furthermore, we assessed in vitro the antioxidant activity and in vivo the antidepressant effect using a rat model and protective effect on lipid peroxidation (in the serum, brain, liver, and stomach). We also conducted molecular docking simulations with proteins involved in oxidative stress and depression for the identified compounds. Antioxidant activity was assessed by measuring total phenolic and flavonoid contents, as well as using 1,1-diphenyl-2-picrylhydrazin (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS), and ferric-reducing antioxidant power (FRAP) assays. Peruvian blueberries demonstrated higher antioxidant activity than fruits from Chile, Brazil, the United States, Turkey, Portugal, and China. The results showed that oral administration of Peruvian blueberries (10 and 20 mg/kg) for 28 days significantly ( < 0.001) increased swimming and reduced immobility in the forced swimming test (FST). Additionally, at doses of 40 and 80 mg/kg, oxidative stress was reduced in vivo ( < 0.001) by decreasing lipid peroxidation in brain, liver, stomach, and serum. Molecular docking and absorption, distribution, metabolism, excretion, and toxicity (ADMET) predictions were performed. In the molecular docking studies, quercitrin and 3,5-di-O-caffeoylquinic acid showed the best docking scores for nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, superoxide dismutase, and xanthine oxidase; while 3,5-dicaffeoylquinic acid methyl ester and caffeoyl coumaroylquinic acid had the best docking scores for monoamine oxidase and serotonin receptor 5-HT. In summary, our results suggest that the antidepressant and protective effects against lipid peroxidation might be related to the antioxidant activity of Peruvian L.
PubMed: 38931078
DOI: 10.3390/plants13121643 -
Antioxidants (Basel, Switzerland) May 2024Insomnia is a major global health issue, highlighting the need for treatments that are both effective and safe. Valerian extract, a traditional remedy for sleep...
Insomnia is a major global health issue, highlighting the need for treatments that are both effective and safe. Valerian extract, a traditional remedy for sleep problems, offers potential therapeutic options. This research examined the potential sleep-enhancing effects of VA (Valerian Pdr%2) in mice. The study evaluated sleep quality by comparing the impact of the VA extract against melatonin on brain activity, using electrocorticography (ECoG) to assess changes in brain waves. For this purpose, the study utilized two experimental models on BALB/c mice to explore the effects of caffeine-induced insomnia and pentobarbital-induced sleep. In the first model, 25 mice were assigned to five groups to test the effects of caffeine (caffeine, 7.5 mg/kg i.p) alone, caffeine with melatonin (2 mg/kg), or caffeine with different doses of valerian extract (100 or 300 mg/kg) given orally on brain activity, assessed via electrocorticography (ECoG) and further analyses on the receptor proteins and neurotransmitters. In the second model, a different set of 25 mice were divided into five groups to examine the impact of pentobarbital (42 mg/kg) alone, with melatonin, or with the valerian extract on sleep induction, observing the effects 45 min after administration. The study found that ECoG frequencies were lower in groups treated with melatonin and two doses of valerian extract (100 and 300 mg/kg), with 300 mg/kg showing the most significant effect in reducing frequencies compared to the caffeine control group, indicating enhanced sleep quality ( < 0.05). This was supported by increased levels of serotonin, melatonin, and dopamine and higher levels of certain brain receptors in the melatonin and valerian extract groups ( < 0.05). Modulatory efficacy for the apoptotic markers in the brain was also noted ( < 0.05). Additionally, melatonin and both doses of VA increased sleep duration and reduced sleep onset time compared to the pentobarbital control, which was particularly notable with high doses. In conclusion, the findings suggest that high doses (300 mg/kg) of valerian extract enhance both the quantity and quality of sleep through the GABAergic pathway and effectively increase sleep duration while reducing the time to fall asleep in a pentobarbital-induced sleep model in mice.
PubMed: 38929096
DOI: 10.3390/antiox13060657 -
Brain Sciences Jun 2024Schizophrenia is a mental disorder affecting approximately 0.32% of the global population, according to the World Health Organization. Antipsychotic medications are used...
BACKGROUND
Schizophrenia is a mental disorder affecting approximately 0.32% of the global population, according to the World Health Organization. Antipsychotic medications are used to treat this condition by inhibiting D2 dopamine and 5HT2 serotonin receptors. The selection of the appropriate mode of delivery for these drugs is based on factors such as patient adherence, clinical presentation, and patient preferences. However, additional drivers of treatment selection are required in clinical practice. Mounting evidence suggests that neuroinflammation plays a crucial role in the pathogenesis of schizophrenia. NLR, a cost-effective biomarker of inflammation, has increased in several psychiatric conditions and may represent a valid method for studying the inflammatory stage in schizophrenia, relapse, and the first episode of psychosis. The aim of this study is to evaluate whether there are any variations in NLR values between patients given oral antipsychotics and those given long-acting antipsychotics.
METHODS
The study included 50 individuals with schizophrenia, either acute or in the follow-up phase. NLR was obtained by calculating the ratio of absolute neutrophil count (cells/μL) and absolute lymphocyte count (cells/μL).
RESULTS
Patients on long-acting antipsychotics exhibited significantly lower mean NLR scores (1.5 ± 0.7) compared to those on oral antipsychotics (2.2 ± 1.3) ( < 0.05).
CONCLUSIONS
NLR appears promising as a neuroinflammatory biomarker. This study reveals significantly lower NLR values in patients on long-acting antipsychotics, which may signify reduced systemic inflammation and improved adherence.
PubMed: 38928602
DOI: 10.3390/brainsci14060602 -
International Journal of Molecular... Jun 2024Phytochemicals and tryptophan (Trp) metabolites have been found to modulate gut function and health. However, whether these metabolites modulate gut ion transport and...
Phytochemicals and tryptophan (Trp) metabolites have been found to modulate gut function and health. However, whether these metabolites modulate gut ion transport and serotonin (5-HT) metabolism and signaling requires further investigation. The aim of this study was to investigate the effects of selected phytochemicals and Trp metabolites on the ion transport and 5-HT metabolism and signaling in the ileum of mice in vitro using the Ussing chamber technique. During the in vitro incubation, vanillylmandelic acid (VMA) reduced ( < 0.05) the short-circuit current, and 100 μM chlorogenic acid (CGA) ( = 0.12) and perillic acid (PA) ( = 0.14) had a tendency to reduce the short-circuit current of the ileum. Compared with the control, PA and -acetylserotonin treatment upregulated the expression of tryptophan hydroxylase 1 (), while 100 μM cinnamic acid, indolelactic acid (ILA), and 10 μM CGA or indoleacetaldehyde (IAld) treatments downregulated ( < 0.05) the mRNA levels of . In addition, 10 μM IAld or 100 μM ILA upregulated ( < 0.05) the expression of monoamine oxidase A (). However, 10 μM CGA or 100 μM PA downregulated ( < 0.05) expression. All selected phytochemicals and Trp metabolites upregulated ( < 0.05) the expression of and compared to that of the control group. VMA and CGA reduced ( < 0.05) the ratios of / and /. These findings may help to elucidate the effects of phytochemicals and Trp metabolites on the regulation of gut ion transport and 5-HT signaling-related gut homeostasis in health and disease.
Topics: Animals; Serotonin; Mice; Ileum; Tryptophan; Signal Transduction; Cinnamates; Ion Transport; Male; Tryptophan Hydroxylase; Chlorogenic Acid
PubMed: 38928404
DOI: 10.3390/ijms25126694 -
International Journal of Molecular... Jun 2024Alcohol use disorder is considered a chronic and relapsing disorder affecting the central nervous system. The serotonergic system, mainly through its influence on the...
Alcohol use disorder is considered a chronic and relapsing disorder affecting the central nervous system. The serotonergic system, mainly through its influence on the mesolimbic dopaminergic reward system, has been postulated to play a pivotal role in the underlying mechanism of alcohol dependence. The study aims to analyse the association of the rs6295 polymorphism of the gene in women with alcohol use disorder and the association of personality traits with the development of alcohol dependence, as well as the interaction of the rs6295, personality traits, and anxiety with alcohol dependence in women. The study group consisted of 213 female volunteers: 101 with alcohol use disorder and 112 controls. NEO Five-Factor and State-Trait Anxiety Inventories were applied for psychometric testing. Genotyping of rs6295 was performed by real-time PCR. We did not observe significant differences in rs6295 genotypes ( = 0.2709) or allele distribution ( = 0.4513). The AUD subjects scored higher on the anxiety trait ( < 0.0001) and anxiety state ( < 0.0001) scales, as well as on the neuroticism ( < 0.0001) and openness ( = 0134) scales. Significantly lower scores were obtained by the AUD subjects on the extraversion ( < 0.0001), agreeability ( < 0.0001), and conscientiousness ( < 0.0001) scales. Additionally, we observed a significant effect of rs6295 genotype interaction and alcohol dependency, or lack thereof, on the openness scale ( = 0.0016). In summary, this study offers a comprehensive overview of alcohol dependence among women. It offers valuable insights into this complex topic, contributing to a more nuanced understanding of substance use among this specific demographic. Additionally, these findings may have implications for developing prevention and intervention strategies tailored to individual genetic and, most importantly, personality and anxiety differences.
Topics: Humans; Female; Receptor, Serotonin, 5-HT1A; Alcoholism; Personality; Adult; Anxiety; Middle Aged; Polymorphism, Single Nucleotide; Genotype; Genetic Predisposition to Disease; Alleles; Genetic Association Studies; Case-Control Studies
PubMed: 38928270
DOI: 10.3390/ijms25126563