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Ghrelin modulates several biological functions via selective activation of the growth hormone secretagogue receptor (GHSR). GHSR agonists may be useful for the treatment of anorexia and cachexia, while antagonists and inverse agonists may represent new drugs for the treatment of metabolic and substance use disorders. Thus, the identification and pharmacodynamic characterization of new GHSR ligands is of high interest. In the present work the label-free dynamic mass redistribution (DMR) assay has been used to evaluate the pharmacological activity of a panel of GHSR ligands. This includes the endogenous peptides ghrelin, desacyl-ghrelin and LEAP2(1-14). Among synthetic compounds, the agonists anamorelin and HM01, the antagonists HM04 and YIL-781, and the inverse agonist PF-05190457 have been tested, together with HM03, R011, and H1498 from patent literature. The DMR results have been compared to those obtained in parallel experiments with the calcium mobilization assay. Ghrelin, anamorelin, HM01, and HM03 behaved as potent full GHSR agonists. YIL-781 behaved as a partial GHSR agonist and R011 as antagonist in both the assays. LEAP2(1-14) resulted a GHSR inverse agonist in DMR but not in calcium mobilization assay. PF-05190457, HM04, and H1498 behaved as GHSR inverse agonists in DMR experiments, while they acted as antagonists in calcium mobilization studies. In conclusion, this study provided a systematic pharmacodynamic characterization of several GHSR ligands in two different pharmacological assays. It demonstrated that the DMR assay can be successfully used particularly to discriminate between antagonists and inverse agonists. This study may be useful for the selection of the most appropriate compounds to be used in future studies.
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Calcio , Ghrelina , Receptores de Ghrelina , Receptores de Ghrelina/agonistas , Receptores de Ghrelina/metabolismo , Receptores de Ghrelina/antagonistas & inhibidores , Ligandos , Ghrelina/farmacología , Ghrelina/metabolismo , Calcio/metabolismo , Humanos , Animales , Cricetulus , Células CHO , Oligopéptidos/farmacología , Fragmentos de Péptidos/farmacología , Fragmentos de Péptidos/metabolismo , Hidrazinas , Piperidinas , QuinazolinonasRESUMEN
This study investigated whether ghrelin mimetics, namely anamorelin and ipamorelin, can alleviate weight loss and inhibition of feeding observed during acute and delayed phases of cisplatin-induced emesis in ferrets. The potential of anamorelin to inhibit electrical field stimulation (EFS)-induced contractions of isolated ferret ileum was compared with ipamorelin. In other experiments, ferrets were administered anamorelin (1-3 mg/kg), ipamorelin (1-3 mg/kg), or vehicle intraperitoneally (i.p.) 30 s before cisplatin (5 mg/kg, i.p.) and then every 24 h, and their behaviour was recorded for up to 72 h. Food and water consumption was measured every 24 h. The effect of anamorelin (10 µg) was also assessed following intracerebroventricular administration. Anamorelin and ipamorelin inhibited EFS-induced contractions of isolated ileum by 94.4 % (half-maximal inhibitory concentration [IC50]=14.0 µM) and 54.4 % (IC50=11.7 µM), respectively. Neither of compounds administered i.p. had any effect on cisplatin-induced acute or delayed emesis, but both inhibited associated cisplatin-induced weight loss on the last day of delayed phase (48-72 h) by approximately 24 %. Anamorelin (10 µg) administered intracerebroventricularly reduced cisplatin-induced acute emesis by 60 % but did not affect delayed emesis. It also improved food and water consumption by approximately 20 %-40 % during acute phase, but not delayed phase, and reduced associated cisplatin-induced weight loss during delayed phase by â¼23 %. In conclusion, anamorelin and ipamorelin administered i.p. had beneficial effects in alleviating cisplatin-induced weight loss during delayed phase, and these effects were seen when centrally administered anamorelin. Anamorelin inhibited cisplatin-induced acute emesis following intracerebroventricular but not intraperitoneal administration, suggesting that brain penetration is important for its anti-emetic mechanism of action.
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Cisplatino , Hurones , Pérdida de Peso , Animales , Pérdida de Peso/efectos de los fármacos , Masculino , Ingestión de Alimentos/efectos de los fármacos , Receptores de Ghrelina/agonistas , Receptores de Ghrelina/antagonistas & inhibidores , Vómitos/inducido químicamente , Vómitos/prevención & control , Vómitos/tratamiento farmacológico , Antieméticos/farmacología , Oligopéptidos/farmacología , Íleon/efectos de los fármacos , Ingestión de Líquidos/efectos de los fármacos , Relación Dosis-Respuesta a DrogaRESUMEN
Histone deacetylase inhibitors (HDACis) are antitumor agents with distinct efficacy in hematologic tumors. Pracinostat is a pan-HDACi with promising early clinical activity. However, similar to other HDACis, its activity as a single agent is limited. Diffuse large B-cell lymphoma (DLBCL) includes distinct molecular subsets or metabolically defined subtypes that rely in different ways on the B-cell receptor signaling pathway, oxidative phosphorylation, and glycolysis for their survival. The antitumor activity of pracinostat has not been determined in lymphomas. We performed preclinical in vitro activity screening of 60 lymphoma cell lines that included 25 DLBCLs. DLBCL cells belonging to distinct metabolic subtypes were treated with HDACis for 6 hours or 14 days followed by transcriptional profiling. DLBCL xenograft models enabled assessment of the in vivo antilymphoma activity of pracinostat. Combination treatments with pracinostat plus 10 other antilymphoma agents were performed. Western blot was used to assess acetylation levels of histone and nonhistone proteins after HDACi treatment. Robust antiproliferative activity was observed across all lymphoma histotypes represented. Focusing on DLBCL, we identified a low-sensitivity subset that almost exclusively consists of the oxidative phosphorylation (OxPhos)-DLBCL metabolic subtype. OxPhos-DLBCL cells also showed poorer sensitivity to other HDACis, including vorinostat. Transcriptomic analysis revealed fewer modulated transcripts but an enrichment of antioxidant pathway genes after HDACi treatment of OxPhos-DLBCLs compared with high-sensitivity B-cell receptor (BCR)-DLBCLs. Pharmacologic inhibition of antioxidant production rescued sensitivity of OxPhos-DLBCLs to pracinostat whereas BCR-DLBCLs were unaffected. Our study provides novel insights into the antilymphoma activity of pracinostat and identifies a differential response of DLBCL metabolic subtypes to HDACis.
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Antineoplásicos , Linfoma de Células B Grandes Difuso , Antineoplásicos/uso terapéutico , Bencimidazoles/uso terapéutico , Inhibidores de Histona Desacetilasas/farmacología , Inhibidores de Histona Desacetilasas/uso terapéutico , Humanos , Linfoma de Células B Grandes Difuso/tratamiento farmacológico , Linfoma de Células B Grandes Difuso/genéticaRESUMEN
PURPOSE: The anti-nociceptive properties of ghrelin have been demonstrated in alleviating inflammatory and neuropathic pain. Whether a ghrelin receptor-mediated mechanism attenuates visceral and somatic pain in the absence of active inflammation remains to be explored. Here, we investigate the efficacy of peripherally restricted (ipamorelin) and a globally active (HM01) selective ghrelin receptor agonist in an experimental model of non-inflammatory visceral hypersensitivity and somatic mechanical allodynia. MATERIALS AND METHODS: Visceral hypersensitivity was induced by dilute acetic acid (0.6%) infusion in the colon of rats in the absence of colonic epithelial inflammation. Ghrelin mimetics HM01 and ipamorelin were administered orally or intravenously, respectively. The ghrelin receptor antagonist H0900 was administered orally. Colonic sensitivity was assessed via a visceromotor behavioral response (VMR) quantified as the number of abdominal contractions in response to graded isobaric pressures (0-60 mmHg) of colorectal distension (CRD). Somatic mechanical allodynia was quantified by the number of ipsilateral paw withdrawals in response to a calibrated von Frey filament. RESULTS: Compared to vehicle controls, ghrelin mimetics HM01 and ipamorelin significantly attenuated colonic hypersensitivity and somatic allodynia. The anti-nociceptive effects of the ghrelin mimetics were blocked after administration of the ghrelin receptor antagonist H0900. CONCLUSION: We have shown that ghrelin receptor-mediated mechanisms are involved in visceral and somatic hypersensitivity in the absence of active colonic inflammation. Furthermore, visceral and somatic hypersensitivity could be attenuated by a peripherally restricted ghrelin mimetic. These results highlight a potential novel approach for treating acute visceral and somatic pain by ghrelin mimetics.
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PURPOSE: Lapatinib is a small molecule tyrosine kinase inhibitor used to treat breast cancer, often in combination with chemotherapy. Diarrhoea commonly occurs in up to 78% of patients undertaking lapatinib treatment. The mechanism of this diarrhoea is currently unknown. Elsiglutide is a GLP-2 analogue known to increase cell proliferation and reduce apoptosis in the intestine. METHODS: We used a previously developed rat model of lapatinib-induced diarrhoea to determine if co-treatment with elsiglutide was able to reduce diarrhoea caused by lapatinib. Additionally, we analysed the caecal microbiome of these rats to assess changes in the microbiome due to lapatinib. RESULTS: Rats treated with lapatinib and elsiglutide had less severe diarrhoea than rats treated with lapatinib alone. Serum lapatinib levels, blood biochemistry, myeloperoxidase levels and serum limulus amebocyte lysate levels were not significantly different between groups. Rats treated with lapatinib alone had significantly higher histopathological damage in the ileum than vehicle controls. This increase was not seen in rats also receiving elsiglutide. Rats receiving lapatinib alone had lower microbial diversity than rats who also received elsiglutide. CONCLUSIONS: Elsiglutide was able to reduce diarrhoea from lapatinib treatment. This does not appear to be via reduction in inflammation or barrier permeability, and may be due to thickening of mucosa, leading to increased surface area for fluid absorption in the distal small intestine. Microbial changes seen in this study require further research to fully elucidate their role in the development of diarrhoea.
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Antidiarreicos/farmacología , Diarrea/tratamiento farmacológico , Péptido 2 Similar al Glucagón/agonistas , Mucosa Intestinal/efectos de los fármacos , Lapatinib/toxicidad , Inhibidores de Proteínas Quinasas/toxicidad , Animales , Antidiarreicos/química , Diarrea/inducido químicamente , Diarrea/patología , Masculino , Ratas , Ratas WistarRESUMEN
The ghrelinergic system has been steadily investigated as a therapeutic target in the treatment of metabolic disorders and modulation of appetite. While endogenous ghrelin activates the full complement of the growth hormone secretagogue receptor (GHSR-1a) pathways, synthetic GHSR-1a ligands display biased signalling and functional selectivity, which have a significant impact on the intended and indeed, unintended, therapeutic effects. The widespread expression of the GHSR-1a receptor in vivo also necessitates an imperative consideration of the biodistribution of GHSR-1a ligands. Here, we investigate anamorelin and HM01, two recently described synthetic GHSR-1a ligands which have shown promising effects on food intake in preclinical and clinical studies. We compare the downstream signalling pathways in cellular in vitro assays, including calcium mobilization, IP-one, internalization and ß-arrestin recruitment assays. We describe a novel divergent activation of central reward circuitry by anamorelin and HM01 using c-Fos immunostaining as well as behavioural effects in food intake and reward paradigms. Interestingly, we found a paradoxical reduction in reward-related behaviour for anamorelin and HM01 treated animals in our chosen paradigms. The work highlights the critical importance to consider signalling bias in relation to future ghrelin-based therapies. In addition, central access of GHSR-1a ligands, particularly to reward areas of the brain, remains a crucial factor in eliciting potent appetite-stimulating effects. The precise characterization of downstream ghrelinergic signalling and biodistribution of novel GHSR-1a ligands will be decisive in their successful development and will allow predictive modelling and design of future synthetic ligands to combat metabolic and appetite disorders involving the ghrelinergic system. This article is part of the special issue on 'Neuropeptides'.
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Apetito/efectos de los fármacos , Ghrelina/farmacología , Hidrazinas/farmacología , Motivación/efectos de los fármacos , Oligopéptidos/farmacología , Piperidinas/farmacología , Recompensa , Animales , Apetito/fisiología , Relación Dosis-Respuesta a Droga , Ingestión de Alimentos/efectos de los fármacos , Ingestión de Alimentos/fisiología , Femenino , Ghrelina/metabolismo , Hidrazinas/metabolismo , Ligandos , Masculino , Ratones , Ratones Endogámicos C57BL , Motivación/fisiología , Oligopéptidos/metabolismo , Piperidinas/metabolismo , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , RoedoresRESUMEN
Insulin-induced hypoglycemia leads to far-ranging negative consequences in patients with diabetes. Components of the counterregulatory response (CRR) system that help minimize and reverse hypoglycemia and coordination between those components are well studied but not yet fully characterized. Here, we tested the hypothesis that acyl-ghrelin, a hormone that defends against hypoglycemia in a preclinical starvation model, is permissive for the normal CRR to insulin-induced hypoglycemia. Ghrelin knockout (KO) mice and wild-type (WT) littermates underwent an insulin bolus-induced hypoglycemia test and a low-dose hyperinsulinemic-hypoglycemic clamp procedure. Clamps also were performed in ghrelin-KO mice and C57BL/6N mice administered the growth hormone secretagogue receptor agonist HM01 or vehicle. Results show that hypoglycemia, as induced by an insulin bolus, was more pronounced and prolonged in ghrelin-KO mice, supporting previous studies suggesting increased insulin sensitivity upon ghrelin deletion. Furthermore, during hyperinsulinemic-hypoglycemic clamps, ghrelin-KO mice required a 10-fold higher glucose infusion rate (GIR) and exhibited less robust corticosterone and growth hormone responses. Conversely, HM01 administration, which reduced the GIR required by ghrelin-KO mice during the clamps, increased plasma corticosterone and growth hormone. Thus, our data suggest that endogenously produced acyl-ghrelin not only influences insulin sensitivity but also is permissive for the normal CRR to insulin-induced hypoglycemia.
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Ghrelina/metabolismo , Hipoglucemia/inducido químicamente , Insulina/toxicidad , Animales , Ghrelina/genética , Técnica de Clampeo de la Glucosa , Hipoglucemia/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fármacos Neuroprotectores/farmacología , Piperidinas/farmacología , Receptores de Ghrelina/agonistasRESUMEN
BACKGROUND AND PURPOSE: HM01, a novel, orally bioavailable, brain-penetrating agonist of ghrelin receptors, ameliorates emesis in Suncus murinus. This study compared HM01's activity against motion sickness with that of the less brain-penetrating ghrelin receptor agonist, HM02. EXPERIMENTAL APPROACH: The potential of HM01 and HM02 to relax isolated mesenteric arteries and to increase feeding was investigated. Radio telemetry was used to record gastric slow waves and body temperature. Plethysmography was used to measure respiratory function. HM01 and HM02 were administered p.o. 1 hr prior to provocative motion, and c-Fos expression in brain sections was assessed. KEY RESULTS: HM01 and HM02 both relaxed precontracted arteries, yielding EC50 values of 2.5 ± 0.5 and 3.5 ± 0.4 nM respectively. HM01 increased feeding, but HM02 did not. Both compounds caused hypothermia and bradygastria. Motion induced 123 ± 24 emetic events. HM01, but not HM02, reduced motion-induced emesis by 67.6%. Motion increased c-Fos expression in the nucleus tractus solitarius (NTS), dorsal motor nucleus of the vagus (DMNV), medial vestibular nucleus (MVe), central nucleus of the amygdala, and paraventricular hypothalamic nucleus (PVH). HM01 alone increased c-Fos expression in the area postrema, NTS, DMNV, PVH, and arcuate hypothalamic nucleus; HM02 had a similar pattern except it did not increase c-Fos in the PVH. Both compounds antagonized the motion-induced increases in c-Fos expression in the MVe. CONCLUSIONS AND IMPLICATIONS: HM01 is more effective than HM02 in preventing motion-induced emesis. The difference in potency may relate to activation of ghrelin receptors in the PVH.
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Receptores de Ghrelina , Musarañas , Animales , Piperidinas , VómitosRESUMEN
Background and objective: Developing therapy for non-motor symptoms of Parkinson's disease (PD) is important for improving patients' quality of life. Previously, we reported that the ghrelin receptor agonist, HM01 normalized the decreased 4-h fecal output and levodopa-inhibited gastric emptying in 6-OHDA rats, and activated selective areas in brain and spinal cord. In this study, we evaluated whether chronic HM01 treatment influences motor functions and/or has beneficial effects on non-motor symptoms including alterations of body weight and composition, defecation, feeding and water intake in 6-OHDA rats. Methods: Male rats were microinjected unilaterally into the medial forebrain bundle with either vehicle or 6-OHDA. Three weeks later, we assessed basal body weight, and 24-h fecal output (pellets, weight, dry weight and water content), water intake and food intake (ingested and spillage). Then, HM01 (3 mg/kg) or vehicle was given per gavage daily for 10-12 days and the same parameters were re-assessed daily. Motor behavior (stepping and rotations tests), body composition were monitored before and after the HM01 treatment. Results: 6-OHDA rats showed motor deficits in rotation test induced by apomorphine and stepping test. They also displayed a significant reduction in body weight, water consumption, fecal weight and water content and an increase in food spillage compared to vehicle microinjected rats. Daily oral treatment of HM01 did not modify motor alterations compared to vehicle but significantly increased the body weight, fat mass, and 24-h fecal weight, fecal water content, food and water intake in 6-OHDA rats, while HM01 had no significant effect in vehicle microinjected rats. Fecal weight and water content were both correlated with water intake, but not with food intake. Fat mass, but not body weight, was correlated with food intake. HM01 effects were significant after 24 h and remained similar during the treatment. Conclusions: Chronic treatment with ghrelin agonist, HM01 improved several non-motor symptoms in the rat PD model induced by 6-OHDA lesion including the decrease in body weight, water consumption, fecal weight and water content, and increased food intake while not improving the motor deficits. These findings provide pre-clinical evidence of potential benefits of ghrelin agonists to alleviate non-motor symptoms in PD patients.
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The gastrointestinal (GI) prokinetic effects of ghrelin occur through direct peripheral effects on ghrelin receptors within the enteric nervous system and via the ghrelin receptor on the vagus nerve, which activate a centrally mediated mechanism. However, the relative contribution of peripheral versus central effects to the overall prokinetic effect of ghrelin agonists requires further investigation. Here, we investigated the central versus peripheral prokinetic effect of ghrelin by using two novel ghrelin agonists: HM01 (N'-[(1S)-1-(2,3-dichloro-4-methoxyphenyl)ethyl]-N-methyl-N-[1,3,3-trimethyl-(4R)-piperidyl]-urea HCL) with high brain penetration compared with HM02 (N'-[(1S)-1-(2,3-dichloro-4-methoxyphenyl)ethyl]-N-hydroxy-N-(1-methyl-4-piperidinyl)-urea), a more peripherally acting ghrelin agonist. The pharmacokinetic profiles of both ghrelin agonists were evaluated after intravenous and oral administration in rats. The efficacy of HM01 and HM02 was assessed in a rat model of postoperative ileus (POI) induced by abdominal surgery and in a rodent defecation assay. Pharmacokinetic results in our models confirmed that HM01, but not HM02, was a brain-penetrant ghrelin agonist. Administration of either HM01 or HM02 reversed the delayed upper and lower gastrointestinal transit induced by abdominal surgery to levels resembling the non-POI controls. In the defecation test, HM01, but not HM02, significantly increased the weight of fecal pellets. Our findings suggest that, in a rodent model of POI, synthetic ghrelin agonists stimulate GI transit through a peripheral site of action. However, in the defecation assay, our data suggest that a ghrelin-mediated mechanism is located at a central site. Taken together, a ghrelin agonist with both central and peripheral prokinetic activity may show therapeutic potential to treat delayed GI transit disorders.
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Materiales Biomiméticos/administración & dosificación , Tránsito Gastrointestinal/fisiología , Ghrelina/administración & dosificación , Ghrelina/agonistas , Piperidinas/administración & dosificación , Administración Intravenosa , Administración Oral , Animales , Relación Dosis-Respuesta a Droga , Motilidad Gastrointestinal/efectos de los fármacos , Motilidad Gastrointestinal/fisiología , Tránsito Gastrointestinal/efectos de los fármacos , Masculino , Ratas , Ratas Sprague-DawleyRESUMEN
In the current study, we sought to determine the significance of the ghrelin system in Prader-Willi Syndrome (PWS). PWS is characterized by hypotonia and difficulty feeding in neonates and hyperphagia and obesity beginning later in childhood. Other features include low GH, neonatal hypoglycemia, hypogonadism, and accelerated mortality. Although the hyperphagia and obesity in PWS have been attributed to elevated levels of the orexigenic hormone ghrelin, this link has never been firmly established, nor have ghrelin's potentially protective actions to increase GH secretion, blood glucose, and survival been investigated in a PWS context. In the current study, we show that placing Snord116del mice modeling PWS on ghrelin-deficient or ghrelin receptor [GH secretagogue receptor (GHSR)]-deficient backgrounds does not impact their characteristically reduced body weight, lower plasma IGF-1, delayed sexual maturation, or increased mortality in the period prior to weaning. However, blood glucose was further reduced in male Snord116del pups on a ghrelin-deficient background, and percentage body weight gain and percentage fat mass were further reduced in male Snord116del pups on a GHSR-deficient background. Strikingly, 2 weeks of daily administration of the GHSR agonist HM01 to Snord116del neonates markedly improved survival, resulting in a nearly complete rescue of the excess mortality owing to loss of the paternal Snord116 gene. These data support further exploration of the therapeutic potential of GHSR agonist administration in limiting PWS mortality, especially during the period characterized by failure to thrive.
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Piperidinas/uso terapéutico , Síndrome de Prader-Willi/tratamiento farmacológico , Síndrome de Prader-Willi/mortalidad , ARN Nucleolar Pequeño/genética , Receptores de Ghrelina/agonistas , Animales , Animales Recién Nacidos , Modelos Animales de Enfermedad , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Piperidinas/farmacología , Síndrome de Prader-Willi/genética , Síndrome de Prader-Willi/patologíaRESUMEN
[This corrects the article DOI: 10.3389/fphar.2018.00869.].
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Chemotherapy-Induced Peripheral Neurotoxicity (CIPN) is often dose-limiting and impacts life quality and survival of cancer patients. Ghrelin agonists have neuroprotectant effects and may have a role in treating or preventing CIPN. We evaluated the CNS-penetrant ghrelin agonist HM01 in three experimental models of CIPN at doses of 3-30â¯mg/kg p.o. daily monitoring orexigenic properties, nerve conduction, mechanical allodynia, and intra-epidermal nerve fiber density (IENFD). In a cisplatin-based study, rats were dosed daily for 3 days (0.5â¯mg/kg i.p.) + HM01. Cisplatin treatment induced mechanical hypersensitivity which was significantly reduced by HM01. In a second study, oxaliplatin was administered to mice (6â¯mg/kg i.p. 3 times/week for 4 weeks) resulting in significant digital nerve conduction velocity (NCV) deficits and reduction of IENFD. Concurrent HM01 dose dependently prevented the decline in NCV and attenuated the reduction in IENFD. Pharmacokinetic studies showed HM01 accumulation in the dorsal root ganglia and sciatic nerves which reached concentrations >â¯10 fold that of plasma. In a third model, HM01 was tested in preventive and therapeutic paradigms in a bortezomib-based rat model (0.2â¯mg/kg i.v., 3 times/week for 8 weeks). In the preventive setting, HM01 blocked bortezomib-induced hyperalgesia and IENFD reduction at all doses tested. In the therapeutic setting, significant effect was observed, but only at the highest dose. Altogether, the robust peripheral nervous system penetration of HM01 and its ability to improve multiple oxaliplatin-, cisplatin-, and bortezomib-induced neurotoxicities suggest that HM01 may be a useful neuroprotective adjuvant for CIPN.
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Antineoplásicos/efectos adversos , Derivados del Benceno/farmacología , Ghrelina/agonistas , Sistema Nervioso/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Animales , Peso Corporal/efectos de los fármacos , Cisplatino/efectos adversos , Relación Dosis-Respuesta a Droga , Ingestión de Alimentos/efectos de los fármacos , Femenino , Masculino , Ratones , Conducción Nerviosa/efectos de los fármacos , Piperidinas , RatasRESUMEN
A new chemotype of ghrelin inverse agonists was discovered through chimeric design based on molecular scaffolds known as growth-hormone secretagogue receptor (GHSR) modulators but with divergent pharmacodynamic and pharmacokinetic properties. The structure-activities/properties exploration led to compound 47, which displayed potent human GHSR antagonism and inverse agonism in cellular assays (IC50 = 68 nM, EC50 = 29 nM), moderate oral bioavailability, and notable brain penetration in rat ( F = 27%, B/ P ratio = 1.9). First in vivo studies demonstrated effective reduction of food intake after oral or parenteral administration to mouse (78% at 1 h and 38% at 8 h, respectively). Further preclinical studies are needed to evaluate the most suited mode of administration with the aim of promoting a first central-acting ghrelin inverse agonist molecule to development, which would represent a significant step toward therapeutic agents to treat metabolic disorders related to obesity, such as type 2 diabetes mellitus.
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Alquinos/síntesis química , Ciclopropanos/síntesis química , Enfermedades Metabólicas/tratamiento farmacológico , Obesidad/complicaciones , Piperidinas/síntesis química , Receptores de Ghrelina/agonistas , Administración Oral , Alquinos/administración & dosificación , Alquinos/farmacología , Animales , Disponibilidad Biológica , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Ciclopropanos/administración & dosificación , Ciclopropanos/farmacología , Perros , Canal de Potasio ERG1/antagonistas & inhibidores , Ingestión de Alimentos/efectos de los fármacos , Humanos , Masculino , Ratones Endogámicos C57BL , Microsomas Hepáticos/efectos de los fármacos , Simulación del Acoplamiento Molecular , Obesidad/metabolismo , Piperidinas/administración & dosificación , Piperidinas/farmacología , Ratas , Receptores de Ghrelina/antagonistas & inhibidores , Receptores de Ghrelina/química , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
Ghrelin has well-known activity to stimulate appetite and weight gain. Evidence suggests that ghrelin may also have effects in reducing chemotherapy-induced emesis via growth hormone secretagogue receptors (GHS-R1A) in the brain. However, it is not known whether the stimulation of GHS-R1A has broad inhibitory anti-emetic effects. In the present studies, we used Suncus murinus to investigate the potential of the new and novel orally bioavailable brain-penetrating GHS-R1A mimetic, HM01 (1-[(1S)-1-(2,3-dichloro-4-methoxyphenyl)ethyl]-3-methyl-3-[(4R)-1-Methyl-3,3-dimethyl-4-piperidyl]urea), to reduce emesis induced by a variety of emetic challenges. HM01 (1 to 30 mg/kg, p.o.) antagonized emesis induced by cisplatin (30 mg/kg, i.p.) and by motion (4 cm horizontal displacement, 1 Hz) but was ineffective against emesis induced by nicotine (5 mg/kg, s.c.) and copper sulfate (120 mg/kg by intragastric gavage). In other experiments, HM01 (3 mg/kg, p.o.) enhanced the anti-emetic control of a regimen of palonosetron (0.01 mg/kg, p.o.) alone and palonosetron (0.01 mg/kg p.o.) plus netupitant (1 mg/kg, p.o.). HM01 (10 mg/kg, p.o.) also had positive effects in increasing feeding and drinking in nicotine-treated animals, and it shortened the latency to drink in animals treated with cisplatin. These data indicate that brain-penetrating GHS-R1A agonists may have use alone and/or in combination with standard anti-emetic regimens for the treatment of chemotherapy-induced nausea and vomiting and motion sickness. Highlights: - The novel orally bioavailable brain-penetrating GHS-R1A agonist, HM01 (1-[(1S)-1-(2,3-dichloro-4-methoxyphenyl)ethyl]-3-methyl-3-[(4R)-1-Methyl-3,3-dimethyl-4-piperidyl]urea), antagonizes motion- and cisplatin-induced emesis.- HM01 did not reduce emesis induced by nicotine or by intragastric copper sulfate.- HM01 has positive effects on food consumption after treatment with nicotine.- HM01 has synergistic effects against cisplatin when combined with palonosetron and palonosetron/netupitant regimens.- It is suggested that GHS-R1A agonists may be protective against chemotherapy-induced nausea and vomiting in combination with traditional anti-emetics and against motion-induced emesis.
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In laboratory animals and in human, centrally penetrant ghrelin receptor agonists, given systemically or orally, cause defecation. Animal studies show that the effect is due to activation of ghrelin receptors in the spinal lumbosacral defecation centers. However, it is not known whether there is a physiological role of ghrelin or the ghrelin receptor in the control of defecation. Using immunohistochemistry and immunoassay, we detected and measured ghrelin in the stomach, but were unable to detect ghrelin by either method in the lumbosacral spinal cord, or other regions of the CNS In rats in which the thoracic spinal cord was transected 5 weeks before, the effects of a ghrelin agonist on colorectal propulsion were significantly enhanced, but defecation caused by water avoidance stress (WAS) was reduced. In knockout rats that expressed no ghrelin and in wild-type rats, WAS-induced defecation was reduced by a ghrelin receptor antagonist, to similar extents. We conclude that the ghrelin receptors of the lumbosacral defecation centers have a physiological role in the control of defecation, but that their role is not dependent on ghrelin. This implies that a transmitter other than ghrelin engages the ghrelin receptor or a ghrelin receptor complex.
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Defecación , Ghrelina/fisiología , Receptores de Ghrelina/fisiología , Médula Espinal/fisiología , Animales , Encéfalo/metabolismo , Mucosa Gástrica/metabolismo , Motilidad Gastrointestinal/efectos de los fármacos , Técnicas de Inactivación de Genes , Ghrelina/genética , Ghrelina/metabolismo , Región Lumbosacra , Masculino , Piperidinas/administración & dosificación , Quinazolinonas/administración & dosificación , Ratas Sprague-Dawley , Receptores de Ghrelina/agonistas , Médula Espinal/metabolismoRESUMEN
The gastrointestinal hormone ghrelin reduces energy expenditure and stimulates food intake. Ghrelin analogs are a possible treatment against cancer anorexia-cachexia syndrome (CACS). This study aimed to investigate whether oral treatment with the non-peptidergic ghrelin receptor agonist HM01 counteracts CACS in colon-26 (C26) tumor-bearing mice. The C26 tumor model is characterized by pronounced body weight (BW) loss and muscle wasting in the absence of severe anorexia. We analyzed the time course of BW loss, body composition, muscle mass, bone mineral density, and the cytokines interleukin-6 (IL-6) and macrophage-inhibitory cytokine-1 (MIC-1). Moreover, we measured the expression of the muscle degradation markers muscle RING-finger-protein-1 (MuRF-1) and muscle atrophy F-box (MAFbx). After tumor inoculation, MIC-1 levels increased earlier than IL-6 and both cytokines were elevated before MuRF-1/MAFbx expression increased. Oral HM01 treatment increased BW, fat mass, and neuronal hypothalamic activity in healthy mice. In tumor-bearing mice, HM01 increased food intake, BW, fat mass, muscle mass, and bone mineral density while it decreased energy expenditure. These effects appeared to be independent of IL-6, MIC-1, MuRF-1 or MAFbx, which were not affected by HM01. Therefore, HM01 counteracts cachectic body weight loss under inflammatory conditions and is a promising compound for the treatment of cancer cachexia in the absence of severe anorexia.
Asunto(s)
Estimulantes del Apetito/uso terapéutico , Caquexia/tratamiento farmacológico , Neoplasias del Colon/complicaciones , Receptores de Ghrelina/agonistas , Tejido Adiposo/efectos de los fármacos , Administración Oral , Animales , Estimulantes del Apetito/administración & dosificación , Peso Corporal/efectos de los fármacos , Densidad Ósea/efectos de los fármacos , Caquexia/etiología , Línea Celular , Citocinas/genética , Citocinas/metabolismo , Factor 15 de Diferenciación de Crecimiento/genética , Factor 15 de Diferenciación de Crecimiento/metabolismo , Hipotálamo/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos DBA , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/metabolismoRESUMEN
AIMS: Ghrelin is implicated in the control of energy balance and glucose homeostasis. The ghrelin receptor exhibits ligand-independent constitutive activity, which can be pharmacologically exploited to induce inverse ghrelin actions. Because ghrelin receptor inverse agonists (GHSR-IA) might be effective for the treatment of obesity-related metabolic disease, we tested 2 novel synthetic compounds GHSR-IA1 and GHSR-IA2. MATERIALS AND METHODS: In functional cell assays, electrophysiogical and immunohistochemical experiments, we demonstrated inverse agonist activity for GHSR-IA1 and GHSR-IA2. We used healthy mice, Zucker diabetic fatty (ZDF) rats and diet-induced obese (DIO) mice to explore effects on food intake (FI), body weight (BW), conditioned taste aversion (CTA), oral glucose tolerance (OGT), pancreatic islet morphology, hepatic steatosis (HS), and blood lipids. RESULTS: Both compounds acutely reduced FI in mice without inducing CTA. Chronic GHSR-IA1 increased metabolic rate in chow-fed mice, suppressed FI, and improved OGT in ZDF rats. Moreover, the progression of islet hyperplasia to fibrosis in ZDF rats slowed down. GHSR-IA2 reduced FI and BW in DIO mice, and reduced fasting and stimulated glucose levels compared with pair-fed and vehicle-treated mice. GHSR-IA2-treated DIO mice showed decreased blood lipids. GHSR-IA1 treatment markedly decreased HS in DIO mice. CONCLUSIONS: Our study demonstrates therapeutic actions of novel ghrelin receptor inverse agonists, suggesting a potential to treat obesity-related metabolic disorders including diabetes mellitus.
Asunto(s)
Fármacos Antiobesidad/uso terapéutico , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Hiperlipidemias/prevención & control , Hipoglucemiantes/uso terapéutico , Enfermedad del Hígado Graso no Alcohólico/prevención & control , Obesidad/tratamiento farmacológico , Receptores de Ghrelina/agonistas , Animales , Fármacos Antiobesidad/efectos adversos , Fármacos Antiobesidad/farmacología , Núcleo Arqueado del Hipotálamo/efectos de los fármacos , Núcleo Arqueado del Hipotálamo/metabolismo , Núcleo Arqueado del Hipotálamo/patología , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patología , Diabetes Mellitus Tipo 2/fisiopatología , Dieta Alta en Grasa/efectos adversos , Agonismo Inverso de Drogas , Ingestión de Energía/efectos de los fármacos , Células HEK293 , Humanos , Hiperlipidemias/etiología , Hipoglucemiantes/efectos adversos , Hipoglucemiantes/farmacología , Islotes Pancreáticos/efectos de los fármacos , Islotes Pancreáticos/metabolismo , Islotes Pancreáticos/patología , Hígado/efectos de los fármacos , Hígado/metabolismo , Hígado/patología , Ratones , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Neuronas/patología , Enfermedad del Hígado Graso no Alcohólico/etiología , Obesidad/metabolismo , Obesidad/patología , Obesidad/fisiopatología , Distribución Aleatoria , Ratas , Ratas Zucker , Receptores de Ghrelina/antagonistas & inhibidores , Receptores de Ghrelina/metabolismo , Aumento de Peso/efectos de los fármacosRESUMEN
BACKGROUND AND AIMS: Chemotherapy-induced acute and delayed emesis involves the activation of multiple pathways, with 5-hydroxytryptamine (5-HT; serotonin) playing a major role in the initial response. Substance P tachykinin NK1 receptor antagonists can reduce emesis induced by disparate emetic challenges and therefore have a clinical utility as broad inhibitory anti-emetic drugs. In the present studies, we investigate the broad inhibitory anti-emetic profile of a relatively new NK1 receptor antagonist, netupitant, alone or in combination with the long acting 5-HT3 receptor antagonist, palonosetron, for a potential to reduce emesis in ferrets and shrews. MATERIALS AND METHODS: Ferrets were pretreated with netupitant and/or palonosetron, and then administered apomorphine (0.125 mg/kg, s.c.), morphine (0.5 mg/kg, s.c.), ipecacuanha (1.2 mg/kg, p.o.), copper sulfate (100 mg/kg, intragastric), or cisplatin (5-10 mg/kg, i.p.); in other studies netupitant was administered to Suncus murinus before motion (4 cm horizontal displacement, 2 Hz for 10 min). RESULTS: Netupitant (3 mg/kg, p.o.) abolished apomorphine-, morphine-, ipecacuanha- and copper sulfate-induced emesis. Lower doses of netupitant (0.03-0.3 mg/kg, p.o.) dose-dependently reduced cisplatin (10 mg/kg, i.p.)-induced emesis in an acute (8 h) model, and motion-induced emesis in S. murinus. In a ferret cisplatin (5 mg/kg, i.p.)-induced acute and delayed emesis model, netupitant administered once at 3 mg/kg, p.o., abolished the first 24 h response and reduced the 24-72 h response by 94.6%; the reduction was markedly superior to the effect of a three times per day administration of ondansetron (1 mg/kg, i.p.). A single administration of netupitant (1 mg/kg, p.o.) plus palonosetron (0.1 mg/kg, p.o.) combined with dexamethasone (1 mg/kg, i.p., once per day), also significantly antagonized cisplatin-induced acute and delayed emesis and was comparable with a once-daily regimen of ondansetron (1 mg/kg, p.o.) plus aprepitant (1 mg/kg, p.o.) in combination with dexamethasone (1 mg/kg, i.p.). CONCLUSION: In conclusion, netupitant has potent and long lasting anti-emetic activity against a number of emetic challenges indicating broad inhibitory properties. The convenience of protection afforded by the single dosing of netupitant together with palonosetron was demonstrated and also is known to provide an advantage over other therapeutic strategies to control emesis in man.
RESUMEN
Introduction. Tachykinins potently contract the isolated urinary bladder from a number of animal species and play an important role in the regulation of the micturition reflex. On the guinea-pig isolated urinary bladder we examined the effects of a new potent and selective NK1 receptor antagonist (netupitant) on the contractions induced by a selective NK1 receptor agonist, SP-methylester (SP-OMe). Moreover, the effects of netupitant and another selective NK1 antagonist (L-733,060) were studied in anesthetized guinea-pigs using two experimental models, the isovolumetric bladder contractions and a model of bladder overactivity induced by intravesical administration of acetic acid (AA). Methods and Results. Detrusor muscle strips were mounted in 5 mL organ baths and isometric contractions to cumulative concentrations of SP-OME were recorded before and after incubation with increasing concentrations of netupitant. In anesthetized female guinea-pigs, reflex bladder activity was examined under isovolumetric conditions with the bladder distended with saline or during cystometry using intravesical infusion of AA. After a 30 min stabilization period, netupitant (0.1-3 mg/kg, i.v.) or L-733,060 (3-10 mg/kg, i.v.) were administered. In the detrusor muscle, netupitant produced a concentration-dependent inhibition (mean pKB = 9.24) of the responses to SP-OMe. Under isovolumetric conditions, netupitant or L-733,060 reduced bladder contraction frequency in a dose-dependent manner, but neither drug changed bladder contraction amplitude. In the AA model, netupitant dose-dependently increased intercontraction interval (ICI) but had no effect on the amplitude of micturition (AM). L-733,060 dose-dependently increased ICI also but this effect was paralleled by a significant reduction of AM. Conclusion. Netupitant decreases the frequency of reflex bladder contractions without altering their amplitude, suggesting that this drug targets the afferent limb of the micturition reflex circuit and therefore may be useful clinically in treating bladder overactivity symptoms.