Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
1.
J Pharmacol Exp Ther ; 373(1): 122-134, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32102919

RESUMO

The 5-hydroxytryptamine (5-HT) (serotonin) 5-HT3 receptor represents a clinical target for antagonists to deliver symptomatic relief to patients with diarrhea-predominant irritable bowel syndrome (IBS-d) or carcinoid syndrome. Unfortunately, this pharmacological strategy can present side effects (e.g., severe constipation). The present study investigates the potential of a novel 5-HT3 receptor partial agonist, CSTI-300, to treat patients with IBS-d and other conditions associated with discomfort from colonic distension, with a predicted reduced side-effect profile. The in vitro and in vivo preclinical pharmacology of the drug CSTI-300 was investigated to explore the potential to treat patients with IBS-d. CSTI-300 displayed selective high affinity for the human and rat 5-HT3 receptor (Ki approximately 2.0 nM) and acted as a partial agonist (approximately 30%-50% intrinsic efficacy) in vitro. In an in vivo model of IBS-d, the rat colon distension model, CSTI-300 displayed dose-dependent efficacy. In addition, oral administration of CSTI-300 to dogs that achieved plasma levels of the drug exceeding the Ki value for the 5-HT3 receptor failed to either evoke emesis or alter the state of feces. Pharmacokinetics for CSTI-300 in rat and dog identified high levels of oral availability with t 1/2 range of 1.6-4.4 hours. The preclinical pharmacology of the lead candidate drug, CSTI-300, supports the potential of this novel drug to offer symptomatic relief to patients with irritable bowel syndrome and carcinoid syndrome with a rationale for a reduced "on-target" side-effect profile relative to 5-HT3 receptor antagonists, such as alosetron. SIGNIFICANCE STATEMENT: There is a lack of effective current treatment for diarrhea-predominant irritable bowel syndrome and carcinoid syndrome, and in both conditions, overactivity of the 5-hydroxytryptamine (5-HT) 5-HT3 receptor is thought to be implicated in the pathophysiology. Because 5-HT3 receptor blockade with antagonists results in significant side effects, we present evidence that treatment with a suitable 5-HT3 receptor partial agonist will alleviate some symptoms associated with these conditions yet, without fully inhibiting the receptor, predict a less pronounced side-effect profile associated with this therapeutic strategy.


Assuntos
Agonismo Parcial de Drogas , Compostos Heterocíclicos com 3 Anéis/química , Compostos Heterocíclicos com 3 Anéis/uso terapêutico , Síndrome do Intestino Irritável/tratamento farmacológico , Síndrome do Carcinoide Maligno/tratamento farmacológico , Agonistas do Receptor 5-HT3 de Serotonina/química , Agonistas do Receptor 5-HT3 de Serotonina/uso terapêutico , Animais , Cães , Relação Dose-Resposta a Droga , Células HEK293 , Humanos , Síndrome do Intestino Irritável/fisiopatologia , Masculino , Síndrome do Carcinoide Maligno/fisiopatologia , Ratos , Ratos Sprague-Dawley , Resultado do Tratamento
2.
Bioorg Med Chem Lett ; 24(11): 2578-81, 2014 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-24755431

RESUMO

Serotonin type 3 (5-HT3) receptor partial agonists have been targeted as potential new drugs for the symptomatic relief of irritable bowel syndrome (IBS). Multiple diazepinone-based compounds have been discovered, which exhibit nanomolar binding affinity for the h5-HT3A receptor and display a range of intrinsic activities (IA=7-87% of 5-HT Emax) in HEK cells heterologously expressing the h5-HT3A receptor. Favorable physicochemical properties and in vitro ADME profile coupled with oral activity in the murine von Bezold-Jarisch reflex model demonstrates the series has promise for producing low to moderate IA partial agonists suitable for an IBS indication.


Assuntos
Azepinas/farmacologia , Descoberta de Drogas , Síndrome do Intestino Irritável/tratamento farmacológico , Receptores 5-HT3 de Serotonina/metabolismo , Administração Oral , Animais , Azepinas/administração & dosagem , Azepinas/química , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Células HEK293 , Humanos , Camundongos , Estrutura Molecular , Relação Estrutura-Atividade
3.
Bioorg Med Chem Lett ; 21(1): 58-61, 2011 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-21146988

RESUMO

Serotonin type 3 (5-HT(3)) receptor partial agonists are being targeted as potential new drugs for the treatment of irritable bowel syndrome (IBS). Two new chemical series bearing indazole and indole cores have exhibited nanomolar binding affinity for the h5-HT(3)A receptor. A range of partial agonist activities in HEK cells heterologously expressing the h5-HT(3)A receptor were measured for the indazole series. Excellent 5-HT(3) receptor selectivity, favorable in vitro metabolic stability and CYP inhibition properties, and good oral in vivo potency in the murine von Bezold-Jarisch reflex model is exemplified thereby indicating the series to have potential utility as improved IBS agents.


Assuntos
Síndrome do Intestino Irritável/tratamento farmacológico , Receptores 5-HT3 de Serotonina/química , Agonistas do Receptor 5-HT3 de Serotonina/química , Animais , Linhagem Celular , Modelos Animais de Doenças , Humanos , Imidazóis/química , Indóis/química , Camundongos , Microssomos Hepáticos/metabolismo , Receptores 5-HT3 de Serotonina/metabolismo , Agonistas do Receptor 5-HT3 de Serotonina/síntese química , Agonistas do Receptor 5-HT3 de Serotonina/uso terapêutico
4.
RSC Chem Biol ; 2(6): 1651-1660, 2021 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-34977580

RESUMO

The metabolism of l-tryptophan to N-formyl-l-kynurenine by indoleamine-2,3-dioxygenase 1 (IDO1) is thought to play a critical role in tumour-mediated immune suppression. Whilst there has been significant progress in elucidating the overall enzymatic mechanism of IDO1 and related enzymes, key aspects of the catalytic cycle remain poorly understood. Here we report the design, synthesis and biological evaluation of a series of tryptophan analogues which have the potential to intercept putative intermediates in the metabolism of 1 by IDO1. Functionally-relevant binding to IDO1 was demonstrated through enzymatic inhibition, however no IDO1-mediated metabolism of these compounds was observed. Subsequent T m-shift analysis shows the most active compound, 17, exhibits a distinct profile from known competitive IDO1 inhibitors, with docking studies supporting the hypothesis that 17 may bind at the recently-discovered Si site. These findings provide a start-point for development of further mechanistic probes and more potent tryptophan-based IDO1 inhibitors.

5.
Sci Rep ; 11(1): 4030, 2021 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-33597595

RESUMO

Blockade of PD-1/PD-L1 interactions is proving an exciting, durable therapeutic modality in a range of cancers whereby T cells are released from checkpoint inhibition to revive their inherent anti-tumour activity. Here we have studied various ways to model ex vivo T cell function in order to compare the impact of the clinically utilised anti-PD-1 antibody, pembrolizumab (Keytruda) on the activation of human T cells: focussing on the release of pro-inflammatory IFNγ and anti-inflammatory IL-10 to assess functionality. Firstly, we investigated the actions of pembrolizumab in an acute model of T-cell activation with either immature or mature allogeneic dendritic cells (DCs); pembrolizumab enhanced IFNγ and IL-10 release from purified CD4+ T-cells in the majority of donors with a bias towards pro-inflammatory cytokine release. Next, we modelled the impact of pembrolizumab in settings of more chronic T-cell activation. In a 7-day antigen-specific response to EBV peptides, the presence of pembrolizumab resulted in a relatively modest increase in both IFNγ and IL-10 release. Where pembrolizumab was assessed against long-term stimulated CD4+ cells that had up-regulated the exhaustion markers TIM-3 and PD-1, there was a highly effective enhancement of the otherwise exhausted response to allogeneic DCs with respect to IFNγ production. By contrast, the restoration of IL-10 production was considerably more limited. Finally, to assess a direct clinical relevance we investigated the consequence of PD-1/PD-L1 blockade in the disease setting of dissociated cells from lung and colon carcinomas responding to allogeneic DCs: here, pembrolizumab once more enhanced IFNγ production from the majority of tumour preparations whereas, again, the increase in IL-10 release was modest at best. In conclusion, we have shown that the contribution of PD-1-revealed by using a canonical blocking antibody to interrupt its interaction with PD-L1-to the production of an exemplar pro- and anti-inflammatory cytokine, respectively, depends in magnitude and ratio on the particular stimulation setting and activation status of the target T cell. We have identified a number of in vitro assays with response profiles that mimic features of dissociated cell populations from primary tumours thereby indicating these represent disease-relevant functional assays for the screening of immune checkpoint inhibitors in current and future development. Such in vitro assays may also support patient stratification of those likely to respond to immuno-oncology therapies in the wider population.


Assuntos
Anticorpos Monoclonais Humanizados/farmacologia , Ativação Linfocitária/efeitos dos fármacos , Linfócitos T/metabolismo , Anticorpos Monoclonais Humanizados/metabolismo , Antígeno B7-H1/efeitos dos fármacos , Antígeno B7-H1/imunologia , Antígeno B7-H1/metabolismo , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Citocinas/imunologia , Receptor Celular 2 do Vírus da Hepatite A/imunologia , Humanos , Inibidores de Checkpoint Imunológico/farmacologia , Imunoterapia/métodos , Ativação Linfocitária/genética , Neoplasias/imunologia , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptor de Morte Celular Programada 1/efeitos dos fármacos , Receptor de Morte Celular Programada 1/metabolismo , Linfócitos T/efeitos dos fármacos
6.
Neuropharmacology ; 52(5): 1284-90, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17327132

RESUMO

The pentameric 5-HT(3) receptor complex is a ligand-gated ion channel that mediates fast synaptic transmission in the brain. Expression of two subunits (5-HT(3A) and 5-HT(3B) subunits) gives rise to at least two receptor isoforms (homomeric 5-HT(3A) and heteromeric 5-HT(3A/3B) receptors), which differ in their biophysical characteristics, although expression of these proteins has not been investigated in human brain. The expression of h5-HT(3A) and 5-HT(3B) subunits in the human hippocampus was investigated using selective polyclonal antibodies (SDS-PAGE/Western blotting, immunohistochemistry), with expression of each subunit verified by PCR detection of subunit transcripts. 5-HT(3A) and 5-HT(3B) subunit immunoreactivity was identified within the human hippocampus. The cellular pattern of expression for each subunit was similar, with predominant immunoreactivity associated with pyramidal neurones in CA fields 2 and 3, and also the relatively large neurones within the hilus (CA4 field). Transcripts for each subunit were also identified in human hippocampal tissue. These findings indicate that human hippocampal neurones are capable of forming at least two, functionally different, isoforms of the 5-HT(3) receptor. Furthermore the expression pattern of 5-HT(3A) and 5-HT(3B) subunits in human hippocampus appears to differ with the rodent counterpart, which may underlie the differences in some of the behavioural effects of 5-HT(3) receptor antagonists between these species.


Assuntos
Hipocampo/metabolismo , Receptores 5-HT3 de Serotonina/efeitos dos fármacos , Adulto , Idoso , Idoso de 80 Anos ou mais , Western Blotting , Linhagem Celular , Eletroforese em Gel de Poliacrilamida , Feminino , Hipocampo/efeitos dos fármacos , Humanos , Imuno-Histoquímica , Isomerismo , Masculino , Pessoa de Meia-Idade , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
7.
Int Immunopharmacol ; 42: 108-114, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27912146

RESUMO

Inosine Acedoben Dimepranol (IAD), licensed for the treatment of cell-mediated immune deficiencies associated with viral infections, has been reported to impact a variety of immune parameters both in vitro and in vivo. Here we report the results from a clinical trial where multiple lymphocyte subsets - CD19+ B cells, CD3+ T cells, CD4+ T-helper cells, FoxP3hi/CD25hi/CD127lo regulatory T cells (Tregs), CD3-/CD56+ NK cells, and CD3+/CD56+ NKT cells - were, together with serum immunoglobulins and IgG subclasses, followed during 14days of IAD administration to ten healthy volunteers; these selected from 27 individuals pre-screened in vitro for their capacity to respond to IAD as gauged by increases in the percentage of Treg and/or NKT cells arising in PHA-stimulated cultures. While a transient spike and dip in Treg and T-helper fractions, respectively, was noted, the outstanding consequence of IAD administration (1g po, qds) was an early and durable rise in NK cells. For half the cohort, NK cells increased as a percentage of total peripheral blood lymphocytes within 1.5h of receiving drug. By Day 5, all but one of the volunteers displayed higher NK cell percentages, such elevation - effectively a doubling or greater - being maintained at termination of study. The IAD-induced populations were as replete in Granzyme A and Perforin as basal NK cells. The novel finding of IAD boosting phenotypically competent NK numbers in healthy individuals supports the drug's indicated benefit in conditions associated with viral infection and reinforces the potential for uplift where immune performance may be compromised.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Fatores Imunológicos/farmacologia , Inosina/farmacologia , Células Matadoras Naturais/efeitos dos fármacos , Subpopulações de Linfócitos/efeitos dos fármacos , Viroses/tratamento farmacológico , para-Aminobenzoatos/farmacologia , Antígenos CD/metabolismo , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Células Cultivadas , Estudos de Coortes , Granzimas/metabolismo , Voluntários Saudáveis , Humanos , Imunofenotipagem , Células Matadoras Naturais/imunologia , Ativação Linfocitária/efeitos dos fármacos , Subpopulações de Linfócitos/imunologia , Perforina/metabolismo , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia
8.
Br J Pharmacol ; 169(6): 1228-38, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23594147

RESUMO

BACKGROUND AND PURPOSE: The 5-HT3 receptor is a ligand-gated ion channel that is modulated allosterically by various compounds including colchicine, alcohols and volatile anaesthetics. However the positive allosteric modulators (PAMs) identified to date have low affinity, which hinders investigation because of non-selective effects at pharmacologically active concentrations. The present study identifies 5-chloroindole (Cl-indole) as a potent PAM of the 5-HT3 receptor. EXPERIMENTAL APPROACH: 5-HT3 receptor function was assessed by the increase in intracellular calcium and single-cell electrophysiological recordings in HEK293 cells stably expressing the h5-HT3A receptor and also the mouse native 5-HT3 receptor that increases neuronal contraction of bladder smooth muscle. KEY RESULTS: Cl-indole (1-100 µM) potentiated agonist (5-HT) and particularly partial agonist [(S)-zacopride, DDP733, RR210, quipazine, dopamine, 2-methyl-5-HT, SR57227A, meta chlorophenyl biguanide] induced h5-HT3A receptor-mediated responses. This effect of Cl-indole was also apparent at the mouse native 5-HT3 receptor. Radioligand-binding studies identified that Cl-indole induced a small (≈ twofold) increase in the apparent affinity of 5-HT for the h5-HT3A receptor, whereas there was no effect upon the affinity of the antagonist, tropisetron. Cl-indole was able to reactivate desensitized 5-HT3 receptors. In contrast to its effect on the 5-HT3 receptor, Cl-indole did not alter human nicotinic α7 receptor responses. CONCLUSIONS AND IMPLICATIONS: The present study identifies Cl-indole as a relatively potent and selective PAM of the 5-HT3 receptor; such compounds will aid investigation of the molecular basis for allosteric modulation of the 5-HT3 receptor and may assist the discovery of novel therapeutic drugs targeting this receptor.


Assuntos
Indóis/farmacologia , Receptores 5-HT3 de Serotonina/metabolismo , Agonistas do Receptor 5-HT3 de Serotonina/farmacologia , Regulação Alostérica , Animais , Sinalização do Cálcio/efeitos dos fármacos , Agonismo Parcial de Drogas , Potenciais Evocados/efeitos dos fármacos , Células HEK293 , Humanos , Técnicas In Vitro , Indóis/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Contração Muscular/efeitos dos fármacos , Proteínas do Tecido Nervoso/agonistas , Proteínas do Tecido Nervoso/antagonistas & inibidores , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Subunidades Proteicas/agonistas , Subunidades Proteicas/antagonistas & inibidores , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Receptores de Serotonina/química , Receptores de Serotonina/genética , Receptores de Serotonina/metabolismo , Receptores 5-HT3 de Serotonina/química , Receptores 5-HT3 de Serotonina/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Agonistas do Receptor 5-HT3 de Serotonina/química , Agonistas do Receptor 5-HT3 de Serotonina/metabolismo , Antagonistas do Receptor 5-HT3 de Serotonina/química , Antagonistas do Receptor 5-HT3 de Serotonina/metabolismo , Antagonistas do Receptor 5-HT3 de Serotonina/farmacologia , Bexiga Urinária/efeitos dos fármacos
9.
Gastroenterology ; 128(5): 1317-26, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15887114

RESUMO

BACKGROUND & AIMS: Serotonin (5-hydroxytryptamine [5-HT]) is a key signaling molecule in the gut. Recently, the neural 5-HT3 receptor received a lot of attention as a possible target in functional bowel diseases. Yet, the 5-HT3 receptor-mediated changes in properties of human enteric neurons is unknown. METHODS: We used a fast imaging technique in combination with the potentiometric dye 1-(3-sulfonatopropyl)-4-[beta[2-(di-n-octylamino)-6-naphthyl]vinyl]pyridinium betaine to monitor directly the membrane potential changes in neurons of human submucous plexus from surgical specimens of 21 patients. An Ussing chamber technique was used to study 5-HT3 receptor involvement in chloride secretion. RESULTS: Local microejection of 5-HT directly onto ganglion cells resulted in a transient excitation of enteric neurons characterized by increased spike discharge. This response was mimicked by the 5-HT3 receptor agonist, 2-methyl-5-HT, and blocked by the 5-HT3 receptor antagonist, tropisetron. The proportions of 5-HT-responsive nerve cells per ganglion ranged from 25.5% +/- 18.4% in the duodenum to 54.2% +/- 46.9% in the colon. Interestingly, 2-methyl-5-HT did not evoke chloride secretion in the human intestine but it did in the guinea-pig intestine. Specific 5-HT3A and 5-HT3B receptor subunit immunoreactivity as well as 5-HT3A and 5-HT3B receptor-specific messenger RNA were detected in the tissue samples. Based on co-labeling with the pan-neuronal marker HuC/D we conclude that submucous nerve cells potentially express heteromeric 5-HT3A/B receptors. CONCLUSIONS: We show that 5-HT excited human enteric neurons via 5-HT3 receptors, which may comprise both 5-HT3A and 5-HT3B receptor subunits.


Assuntos
Neurônios/fisiologia , Receptores 5-HT3 de Serotonina/metabolismo , Serotonina/farmacologia , Plexo Submucoso/efeitos dos fármacos , Plexo Submucoso/fisiologia , Potenciais de Ação/efeitos dos fármacos , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Linhagem Celular , Cloretos/metabolismo , Cultura em Câmaras de Difusão , Feminino , Cobaias , Humanos , Imuno-Histoquímica , Rim/citologia , Masculino , Pessoa de Meia-Idade , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Receptores 5-HT3 de Serotonina/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Plexo Submucoso/citologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA