RESUMEN
Somatostatin inhibits endocrine and exocrine secretion in various tissues by acting on five somatostatin receptor subtypes (SSTR1-5). The clinical effects of SSTR5 antagonism remain unknown. Herein, we evaluated the effects of SCO-240, an oral SSTR5 antagonist, in healthy individuals. This randomized, single-center, double-blind, placebo-controlled, phase I study included healthy Japanese and White individuals. The effects of ascending single oral doses of SCO-240 were evaluated in healthy individuals. The main outcome measures were safety, tolerability, pharmacokinetics, and pharmacodynamics (gallbladder contractions and levels of serum insulin and plasma glucagon-like peptide-1 (GLP-1)). The levels of pituitary hormones were evaluated in our exploratory analysis. The results indicated that SCO-240 was safe and well-tolerated at all tested doses. Oral SCO-240 was readily absorbed, with its systemic exposure increasing in a dose-dependent manner. The median time to maximum concentration and mean terminal half-life of SCO-240 were 3-4 and 10.2-12.6 hours, respectively, in the ascending dose section. No clinically meaningful changes in SCO-240 pharmacokinetic profiles were observed between fed and fasted or between Japanese and White individuals. No increase in gallbladder contractions or levels of insulin and GLP-1 were detected. SCO-240 induced robust growth hormone (GH) secretion without altering the levels of other pituitary hormones. In conclusion, the study is the first to demonstrate that SSTR5 antagonism stimulates GH secretion in humans. SCO-240 was safe and well-tolerated and exhibited once-daily oral dosing potential. The robust effects of SCO-240 on GH secretion suggest that it may be a treatment option for GH-related disorders.
Asunto(s)
Voluntarios Sanos , Receptores de Somatostatina , Humanos , Masculino , Adulto , Método Doble Ciego , Femenino , Receptores de Somatostatina/antagonistas & inhibidores , Administración Oral , Adulto Joven , Hormona de Crecimiento Humana/administración & dosificación , Relación Dosis-Respuesta a Droga , Péptido 1 Similar al Glucagón , Insulina/sangre , Vesícula Biliar/metabolismo , Vesícula Biliar/efectos de los fármacos , Persona de Mediana EdadRESUMEN
Introduction: Elevated plasma amino acid levels overload kidney function by increasing glomerular filtration rate (GFR). Inhibiting gut amino acid intake may have therapeutic benefits for patients with kidney dysfunction. For a prospective phase 2a trial, we carried out an exploratory evaluation of the safety and efficacy of SCO-792, an enteropeptidase inhibitor that blocks gut amino acid intake, in patients with type 2 diabetes mellitus (T2DM) and albuminuria. Methods: Seventy-two patients with T2DM, a urine albumin-to-creatinine ratio (UACR) of 200-5000 mg/g, and an estimated GFR >30 ml/min per 1.73 m2 were included. Patients were randomly assigned (1:2:2) to the following groups and received treatment for 12 weeks: placebo (n = 15), SCO-792 500 mg once daily (SCO-792 QD; n = 29), or SCO-792 500 mg 3 times daily (SCO-792 3 times a day (TID); n = 28) by following a double-blind approach. We evaluated UACR changes from the baseline along with safety as the primary end points and other parameters as secondary or exploratory end points. Results: SCO-792 was safe and well tolerated up to 1500 mg/day for 12 weeks. UACR changes from baseline were -14% (P = 0.4407), -27% (P = 0.0271), and -28% (P = 0.0211) in placebo, SCO-792 QD, and SCO-792 TID, respectively, whereas UACR changes in SCO-792 groups were not statistically significant compared with placebo. The hemoglobin A1c (HbA1c) levels from baseline, an exploratory end point, decreased in the SCO-792 TID group. Conclusion: SCO-792 was safe and well tolerated for 12 weeks and may be associated with decreased UACR in patients with T2DM and albuminuria. Further clinical studies are essential to confirm our findings.
RESUMEN
Diphosphoinositol pentakisphosphate (InsP7) is an inositol pyrophosphate generated by inositol hexakisphosphate kinases (IP6Ks) that regulate diverse biological functions in cells. To date, we have a limited understanding of the InsP7 biology owing to limited data on InsP7 levels in blood or other tissues. Given the significant role of InsP7 in maintaining biological homeostasis, further advancement in InsP7 measurement is essential. In this study, we report a highly sensitive liquid chromatography with tandem mass spectrometry method for determining InsP7 levels in whole blood, which is an easily accessible tissue and for which knowledge on InsP7 levels is limited. We applied a perchloric acid-based method to increase the extraction efficiency of InsP7 from the cells. Subsequently, we combined a YMC-Triart C18 metal-free column, ion-pair reagents, EDTA, methylenediphosphonic acid, and N,N,N',N'-Ethylenediaminetetrakis(methylenephosphonic acid) to minimize InsP7 adsorption to the detection system. We prepared blood quality control samples that were highly exposed to IP6K inhibitor, showing minimum InsP7 levels, to decrease the lower quantification limit of InsP7. Furthermore, we applied rat plasma, which was found to show no InsP7 levels, as a surrogate matrix. This setting resulted in the highly sensitive detection of InsP7 levels in blood obtained from rats, with a quantification sensitivity of 1 ng of InsP7 per mL of blood. The current method demonstrated acceptable accuracy (100 ± 15%) and precision (coefficient of variation ≤ 15%) in rat blood. Using this method, we revealed endogenous basal levels of InsP7 (37.4 ng/mL) in blood obtained from normal rats, and decreased levels of InsP7 (4.1-21.7 ng/mL) in blood obtained from IP6K inhibitor-administered rats. In summary, we established a highly sensitive method for measuring InsP7 and revealed its levels in rat blood. The current findings may help in understanding InsP7 biology.
Asunto(s)
Difosfatos , Ácido Fítico , Animales , Cromatografía Liquida , Ácido Edético , Fosfatos de Inositol , Ratas , Espectrometría de Masas en TándemRESUMEN
AIMS: Pyruvate dehydrogenase (PDH) catalyzes the decarboxylation of pyruvate to acetyl-CoA, which plays a key role in linking cytosolic glycolysis to mitochondria metabolism. PDH is physiologically inactivated by pyruvate dehydrogenase kinases (PDKs). Thus, activation of PDH via inhibiting PDK may lead to metabolic benefits. In the present study, we investigated the antidiabetic effect of PDK inhibition using dichloroacetate (DCA), a PDK inhibitor. MAIN METHODS: We evaluated the effect of single dose of DCA on plasma metabolic parameters in normal rats. Next, we investigated the antidiabetic effect of DCA in diabetic ob/ob mice. In addition, we performed in vitro assays to understand the effect and mechanism of action of DCA on gluconeogenesis in mouse myoblast cell line C2C12 and rat hepatoma cell line FaO. KEY FINDINGS: In normal rats, a single dose of DCA decreased the plasma level of pyruvate, the product of glycolysis, and the plasma glucose level only in the fasting state. Meanwhile, a single dose of DCA lowered the plasma glucose level, and a three-week treatment decreased the fructosamine level in diabetic ob/ob mice. In vitro experiments demonstrated concentration-dependent suppression of lactate production in C2C12 myotubes. In addition, DCA suppressed glucose production from pyruvate and lactate in FaO hepatoma cells. Thus, DCA-mediated restricted supply of gluconeogenic substrates from the muscle to liver, and direct suppression of hepatic gluconeogenesis might have contributed to its glucose-lowering effect in the current models. SIGNIFICANCE: PDK inhibitor may be considered as a potential antidiabetic agent harboring inhibitory effect on gluconeogenesis.
RESUMEN
Circulating phosphate levels are tightly controlled within a narrow range in mammals. By using a novel small-molecule inhibitor, we show that the enzymatic activity of inositol hexakisphosphate kinases (IP6K) is essential for phosphate regulation in vivo. IP6K inhibition suppressed XPR1, a phosphate exporter, thereby decreasing cellular phosphate export, which resulted in increased intracellular ATP levels. The in vivo inhibition of IP6K decreased plasma phosphate levels without inhibiting gut intake or kidney reuptake of phosphate, demonstrating a pivotal role of IP6K-regulated cellular phosphate export on circulating phosphate levels. IP6K inhibition-induced decrease in intracellular inositol pyrophosphate, an enzymatic product of IP6K, was correlated with phosphate changes. Chronic IP6K inhibition alleviated hyperphosphataemia, increased kidney ATP, and improved kidney functions in chronic kidney disease rats. Our results demonstrate that the enzymatic activity of IP6K regulates circulating phosphate and intracellular ATP and suggest that IP6K inhibition is a potential novel treatment strategy against hyperphosphataemia.
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Fosfatos/sangre , Fosfotransferasas (Aceptor del Grupo Fosfato)/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Transporte Biológico/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/uso terapéutico , Homeostasis/efectos de los fármacos , Humanos , Hiperfosfatemia/tratamiento farmacológico , Fosfatos de Inositol/metabolismo , Mamíferos , Fosfatos/metabolismo , Fosfotransferasas (Aceptor del Grupo Fosfato)/antagonistas & inhibidores , Ratas , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Receptores Virales/genética , Receptores Virales/metabolismo , Insuficiencia Renal Crónica/tratamiento farmacológico , Receptor de Retrovirus Xenotrópico y PolitrópicoRESUMEN
SCO-267 is a full agonist of the free fatty acid receptor 1 (GPR40), which regulates the secretion of islet and gut hormones. In this phase 1 study, we aimed to evaluate the clinical profile of single and multiple once-daily oral administration of SCO-267 in healthy adults and patients with diabetes. Plasma SCO-267 concentration was seen to increase in a dose-dependent manner after administration, and its plasma exposure was maintained for 24 h. Repeated dose did not alter the pharmacokinetic profile of SCO-267 in healthy adults. SCO-267 was generally safe and well tolerated at all evaluated single and multiple doses. Single and repeated doses of SCO-267 stimulated the secretion of insulin, glucagon, glucagon-like peptide 1, glucose-dependent insulinotropic polypeptide, and peptide YY in healthy adults. Furthermore, a single dose of SCO-267 stimulated the secretion of these hormones, decreased fasting hyperglycemia, and improved glycemic control during an oral glucose tolerance test in patients with diabetes, without inducing hypoglycemia. This study is the first to demonstrate the clinical effects of a GPR40 full agonist. SCO-267 is safe and well tolerated and exhibits once-daily oral dosing potential. Its robust therapeutic effects on hormonal secretion and glycemic control make SCO-267 an attractive drug candidate for the treatment of diabetes.
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Glucemia/efectos de los fármacos , Hormonas Gastrointestinales/metabolismo , Islotes Pancreáticos/efectos de los fármacos , Piperidinas/farmacología , Piridinas/farmacología , Adulto , Anciano , Glucemia/metabolismo , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Método Doble Ciego , Intolerancia a la Glucosa/tratamiento farmacológico , Intolerancia a la Glucosa/metabolismo , Prueba de Tolerancia a la Glucosa , Control Glucémico/métodos , Humanos , Secreción de Insulina/efectos de los fármacos , Islotes Pancreáticos/metabolismo , Japón , Masculino , Persona de Mediana Edad , Piperidinas/administración & dosificación , Piridinas/administración & dosificación , Receptores Acoplados a Proteínas G/agonistas , Adulto JovenRESUMEN
Full agonist-mediated activation of free fatty acid receptor 1 (FFAR1/GPR40) alleviates diabetes in rodents. Considering that diabetes is a chronic disease, assessment of treatment durability of chronic exposure to a GPR40 full agonist is pivotal for treating patients with diabetes. However, the physiologic significance of chronic in vitro and in vivo exposure to GPR40 full agonists is largely unclear. Here, we evaluated the in vitro and in vivo effects of chronic treatment with SCO-267, a GPR40 full agonist, on signal transduction and glucose control. In vitro experiments showed that SCO-267 is an allosteric full agonist for GPR40, which activates the Gα q, Gα s, and Gα 12/13 pathways and ß-arrestin recruitment. The calcium signal response was largely sustained in GPR40-overexpressing CHO cells even after prolonged incubation with SCO-267. To evaluate the in vivo relevance of chronic exposure to GPR40 full agonists, SCO-267 (1 and 10 mg/kg) was administered once daily to neonatally streptozotocin-induced diabetic rats for 15-33 days, and glucose control was evaluated. After 15 days of dosing followed by the drug washout period, SCO-267 improved glucose tolerance, most likely by increasing insulin sensitivity in rats. After 33 days, repeated exposure to SCO-267 was highly effective in improving glucose tolerance in rats. Furthermore, chronic exposure to SCO-267 increased pancreatic insulin content. These results demonstrated that even after chronic exposure, SCO-267 effectively activates GPR40 in cells and rats, suggesting the clinical application of SCO-267 in treating chronic diseases including diabetes. SIGNIFICANCE STATEMENT: GPR40 is a validated therapeutic target for diabetes. This study showed that even after chronic exposure, SCO-267, an allosteric GPR40 full agonist, effectively activates GPR40 in cells and rats; these results suggest a durable efficacy of SCO-267 in patients.
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Glucemia/efectos de los fármacos , Diabetes Mellitus Experimental/tratamiento farmacológico , Control Glucémico/métodos , Piperidinas/administración & dosificación , Piridinas/administración & dosificación , Receptores Acoplados a Proteínas G/agonistas , Animales , Glucemia/metabolismo , Células CHO , Cricetinae , Cricetulus , Diabetes Mellitus Experimental/sangre , Relación Dosis-Respuesta a Droga , Humanos , Masculino , Ratas , Ratas Endogámicas WKY , Receptores Acoplados a Proteínas G/metabolismoRESUMEN
AIM: To examine the effects of an enteropeptidase inhibitor, SCO-792, on kidney function in rats. MATERIALS AND METHODS: The pharmacological effects of SCO-792 were evaluated in Wistar fatty (WF) rats, a rat model of diabetic kidney disease (DKD). RESULTS: Oral administration of SCO-792 increased faecal protein content and improved glycaemic control in WF rats. SCO-792 elicited a rapid decrease in urine albumin-to-creatinine ratio (UACR). SCO-792 also normalized glomerular hyperfiltration and decreased fibrosis, inflammation and tubular injury markers in the kidneys. However, pioglitazone-induced glycaemic improvement had no effect on kidney variables. Dietary supplementation of amino acids (AAs), which bypass the action of enteropeptidase inhibition, mitigated the effect of SCO-792 on UACR reduction, suggesting a pivotal role for enteropeptidase. Furthermore, autophagy activity in the glomerulus, which is impaired in DKD, was elevated in SCO-792-treated rats. Finally, a therapeutically additive effect on UACR reduction was observed with a combination of SCO-792 with irbesartan, an angiotensin II receptor blocker. CONCLUSIONS: This study is the first to demonstrate that enteropeptidase inhibition is effective in improving disease conditions in DKD. SCO-792-induced therapeutic efficacy is likely to be independent of glycaemic control and mediated by the regulation of AAs and autophagy. Taken together with a combination effect of irbesartan, SCO-792 may be a novel therapeutic option for patients with DKD.
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Diabetes Mellitus , Nefropatías Diabéticas , Enteropeptidasa/antagonistas & inhibidores , Riñón , Animales , Nefropatías Diabéticas/tratamiento farmacológico , Glomérulos Renales , Ratas , Ratas WistarRESUMEN
BACKGROUND: Inhibiting enteropeptidase, a gut serine protease regulating protein digestion, suppresses food intake and ameliorates obesity and diabetes in mice. However, the effects of enteropeptidase inhibition on kidney parameters are largely unknown. Here, we evaluated the chronic effects of an enteropeptidase inhibitor, SCO-792, on kidney function, albuminuria and kidney pathology in spontaneously hypercholesterolaemic (SHC) rats, a rat chronic kidney disease (CKD) model. METHODS: SCO-792, an orally available enteropeptidase inhibitor, was administered [0.03% and 0.06% (w/w) in the diet] to 20-week-old SHC rats showing albuminuria and progressive decline in glomerular filtration rate (GFR) for five weeks. The effects of SCO-792 and the contribution of amino acids to these effects were evaluated. RESULTS: SCO-792 increased the faecal protein content, indicating that SCO-792 inhibited enteropeptidase in SHC rats. Chronic treatment with SCO-792 prevented GFR decline and suppressed albuminuria. Moreover, SCO-792 improved glomerulosclerosis and kidney fibrosis. Pair feeding with SCO-792 (0.06%) was less effective in preventing GFR decline, albuminuria and renal histological damage than SCO-792 treatment, indicating the enteropeptidase-inhibition-dependent therapeutic effects of SCO-792. SCO-792 did not affect the renal plasma flow, suggesting that its effect on GFR was mediated by an improvement in filtration fraction. Moreover, SCO-792 increased hydrogen sulphide production capacity, which has a role in tissue protection. Finally, methionine and cysteine supplementation to the diet abrogated SCO-792-induced therapeutic effects on albuminuria. CONCLUSIONS: SCO-792-mediated inhibition of enteropeptidase potently prevented GFR decline, albuminuria and kidney fibrosis; hence, it may have therapeutic potential against CKD.
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Albuminuria/tratamiento farmacológico , Enteropeptidasa/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Fibrosis/tratamiento farmacológico , Hipercolesterolemia/fisiopatología , Enfermedades Renales/tratamiento farmacológico , Insuficiencia Renal Crónica/complicaciones , Albuminuria/etiología , Albuminuria/patología , Animales , Fibrosis/etiología , Fibrosis/patología , Tasa de Filtración Glomerular , Enfermedades Renales/etiología , Enfermedades Renales/patología , Masculino , RatasRESUMEN
Enteropeptidase is a transmembrane serine protease localized in the lumen of the duodenum that acts as a key enzyme for protein digestion. SCO-792 is an orally available enteropeptidase inhibitor that has been reported to have therapeutic effects on obesity and diabetes in mice. However, the mechanism underlying the therapeutic effect of SCO-792 has not yet been fully elucidated. In this study, we evaluated the role of gut microbiota on SCO-792-induced body weight (BW) reduction in high-fat diet-induced obese (DIO) mice. Chronic administration of SCO-792 substantially decreased BW and food intake in DIO mice. While the pair-fed study uncovered food intake-independent mechanisms of BW reduction by SCO-792. Interestingly, antibiotics-induced microbiota elimination in the gut canceled SCO-792-induced BW reduction by nearly half without affecting the anorectic effect, indicating the involvement of gut microbiota in the anti-obesity mechanism that is independent of food intake reduction. Microbiome analysis revealed that SCO-792 altered the gut microbiota composition in DIO mice. Notably, it was found that the abundance of Firmicutes decreased while that of Verrucomicrobia increased at the phylum level. Increased abundance of Akkermansia muciniphila, a bacterium known to be useful for host metabolism, was observed in SCO-792-treated mice. Fecal metabolome analysis revealed increased amino acid levels, indicating gut enteropeptidase inhibition. In addition, SCO-792 was found to increase the level of short-chain fatty acids, including propionate, and bile acids in the feces, which all help maintain gut health and improve metabolism. Furthermore, it was found that SCO-792 induced the elevation of colonic immunoglobulin A (IgA) concentration, which may maintain the microbiota condition, in DIO mice. In conclusion, this study demonstrates the contribution of microbiota to SCO-792-induced BW reduction. Enteropeptidase-mediated regulation of microbiota, enterobacterial metabolites, and IgA in the gut may coordinately drive the therapeutic effects of SCO-792 in obesity.
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Fármacos Antiobesidad/uso terapéutico , Enteropeptidasa/antagonistas & inhibidores , Microbioma Gastrointestinal/efectos de los fármacos , Obesidad/tratamiento farmacológico , Akkermansia/genética , Animales , Fármacos Antiobesidad/farmacología , Ácidos y Sales Biliares/metabolismo , Dieta Alta en Grasa , Dieta Occidental , Enterobacteriaceae/metabolismo , Ácidos Grasos Volátiles/metabolismo , Heces/química , Inmunoglobulina A/metabolismo , Masculino , Ratones Endogámicos C57BL , Obesidad/microbiología , ARN Ribosómico 16S/genéticaRESUMEN
GPR40/FFAR1 is a G-protein-coupled receptor expressed in pancreatic ß-cells and enteroendocrine cells. GPR40 activation stimulates secretions of insulin and incretin, both of which are the pivotal regulators of glycemic control. Therefore, a GPR40 agonist is an attractive target for the treatment of type 2 diabetes mellitus. Using the reported biaryl derivative 1, we shifted the hydrophobic moiety to the terminal aryl ring and replaced the central aryl ring with piperidine, generating 2-(4,4-dimethylpentyl)phenyl piperidine 4a, which had improved potency for GPR40 and high lipophilicity. We replaced the hydrophobic moiety with N-alkyl-N-aryl benzamides to lower the lipophilicity and restrict the N-alkyl moieties to the presumed lipophilic pocket using the intramolecular π-π stacking of cis-preferential N-alkyl-N-aryl benzamide. Among these, orally available (3S)-3-cyclopropyl-3-(2-((1-(2-((2,2-dimethylpropyl)(6-methylpyridin-2-yl)carbamoyl)-5-methoxyphenyl)piperidin-4-yl)methoxy)pyridin-4-yl)propanoic acid (SCO-267) effectively stimulated insulin secretion and GLP-1 release and ameliorated glucose tolerance in diabetic rats via GPR40 full agonism.
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Benzamidas/uso terapéutico , Diabetes Mellitus Experimental/tratamiento farmacológico , Hipoglucemiantes/uso terapéutico , Piperidinas/uso terapéutico , Receptores Acoplados a Proteínas G/agonistas , Animales , Benzamidas/síntesis química , Benzamidas/farmacocinética , Células CHO , Cricetulus , Hipoglucemiantes/síntesis química , Hipoglucemiantes/farmacocinética , Masculino , Ratones Endogámicos ICR , Estructura Molecular , Piperidinas/síntesis química , Piperidinas/farmacocinética , Ratas Sprague-Dawley , Relación Estructura-ActividadRESUMEN
Full agonism of G-protein-coupled receptor 40 (GPR40)/free fatty acid 1 receptor improves glycemic control in diabetic rodents. However, the effects of GPR40 full agonism on liver parameters are largely unknown. In the present study, we examined the effects of a GPR40 full agonist, SCO-267, on liver parameters in a nondiabetic mouse model with early-stage nonalcoholic fatty liver disease (NAFLD). SCO-267 was orally administered to mice, which were fed a choline-deficient, l-amino acid-defined, high-fat diet (CDAHFD), a mouse model for NAFLD. An oral dose of SCO-267 increased levels of circulating glucagon and glucagon-like peptide-1 in CDAHFD-fed mice. In a chronic-dose experiment, effects of SCO-267 were compared with those of a dipeptidyl peptidase-4 inhibitor (alogliptin) and a sodium glucose cotransporter 2 inhibitor (dapagliflozin). SCO-267 decreased liver triglyceride content, weight, collagen content, and plasma alanine aminotransferase (ALT) levels without affecting food intake or glucose levels in CDAHFD-fed mice. Furthermore, SCO-267 decreased levels of liver thiobarbituric acid reactive substances (TBARS), markers of oxidative stress. Alogliptin and dapagliflozin had no effect on liver weight or levels of triglyceride, collagen, plasma ALT, and liver TBARS. SCO-267 elevated mRNA levels of molecules with roles in mitochondrial function and ß-oxidation while inhibiting those with roles in lipogenesis, inflammation, reactive oxygen species generation, and fibrosis in the liver, all of which were less evident with alogliptin and dapagliflozin. This is the first study to show that the GPR40 full agonist SCO-267 improves liver parameters without affecting glucose or body weight in a mouse model of NAFLD. SIGNIFICANCE STATEMENT: Full agonism of GPR40/free fatty acid 1 receptor signaling stimulates islet and gut hormone secretions. The present study is the first to show the treatment effects of GPR40 full agonism on liver parameters in a mouse model for nonalcoholic fatty liver disease.
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Peso Corporal/efectos de los fármacos , Glucosa/metabolismo , Hígado/efectos de los fármacos , Enfermedad del Hígado Graso no Alcohólico/tratamiento farmacológico , Receptores Acoplados a Proteínas G/agonistas , Administración Oral , Animales , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Glucagón/sangre , Péptido 1 Similar al Glucagón/sangre , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Triglicéridos/metabolismoRESUMEN
GPR40/FFAR1 is a Gq protein-coupled receptor expressed in pancreatic ß cells and enteroendocrine cells, and mediates insulin and incretin secretion to regulate feeding behavior. Several GPR40 full agonists have been reported to reduce food intake in rodents by regulating gut hormone secretion in addition to their potent glucose-lowering effects; however, detailed mechanisms of feeding suppression are still unknown. In the present study, we characterized T-3601386, a novel compound with potent full agonistic activity for GPR40, by using in vitro Ca2+ mobilization assay in Chinese hamster ovary (CHO) cells expressing FFAR1 and in vivo hormone secretion assay. We also evaluated feeding suppression and weight loss after the administration of T-3601386 and investigated the involvement of the vagal nerve in these effects. T-3601386, but not a partial agonist fasiglifam, increased intracellular Ca2+ levels in CHO cells with low FFAR1 expression, and single dosing of T-3601386 in diet-induced obese (DIO) rats elevated plasma incretin levels, suggesting full agonistic properties of T-3601386 against GPR40. Multiple doses of T-3601386, but not fasiglifam, in DIO rats showed dose-dependent weight loss accompanied by feeding suppression and durable glucagon-like peptide-1 elevation, all of which were completely abolished in Ffar1-/- mice. Immunohistochemical analysis in the nuclei of the solitary tract demonstrated that T-3601386 increased the number of c-Fos positive cells, which also disappeared in Ffar1-/- mice. Surgical vagotomy and drug-induced deafferentation counteracted the feeding suppression and weight loss induced by the administration of T-3601386. These results suggest that T-3601386 exerts incretin release and weight loss in a GPR40-dependent manner, and that afferent vagal nerves are important for the feeding suppression induced by GPR40 full agonism. Our novel findings raise the possibility that GPR40 full agonist can induce periphery-derived weight reduction, which may provide benefits such as less adverse effects in central nervous system compared to centrally-acting anti-obesity drugs.
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Receptores Acoplados a Proteínas G/metabolismo , Pérdida de Peso/fisiología , Animales , Glucemia/metabolismo , Glucemia/fisiología , Células CHO , Calcio/metabolismo , Línea Celular , Cricetulus , Células Enteroendocrinas/metabolismo , Femenino , Péptido 1 Similar al Glucagón/metabolismo , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Islotes Pancreáticos/metabolismo , Masculino , Ratones , Obesidad/metabolismo , Obesidad/fisiopatología , Ratas , Ratas Endogámicas F344 , Ratas Sprague-Dawley , Ratas Wistar , Transducción de Señal , Nervio Vago/metabolismo , Nervio Vago/fisiologíaRESUMEN
Enteropeptidase, localized into the duodenum brush border, is a key enzyme catalyzing the conversion of pancreatic trypsinogen proenzyme to active trypsin, thereby regulating protein digestion and energy homeostasis. We report the discovery and pharmacological profiles of SCO-792, a novel inhibitor of enteropeptidase. A screen employing fluorescence resonance energy transfer was performed to identify enteropeptidase inhibitors. Inhibitory profiles were determined by in vitro assays. To evaluate the in vivo inhibitory effect on protein digestion, an oral protein challenge test was performed in rats. Our screen identified a series of enteropeptidase inhibitors, and compound optimization resulted in identification of SCO-792, which inhibited enteropeptidase activity in vitro, with IC 50 values of 4.6 and 5.4 nmol/L in rats and humans, respectively. In vitro inhibition of enteropeptidase by SCO-792 was potentiated by increased incubation time, and the calculated Kinact/KI was 82 000/mol/L s. An in vitro dissociation assay showed that SCO-792 had a dissociation half-life of almost 14 hour, with a calculated koff rate of 0.047/hour, which suggested that SCO-792 is a reversible enteropeptidase inhibitor. In normal rats, a ≤4 hour prior oral dose of SCO-792 effectively inhibited plasma elevation of branched-chain amino acids in an oral protein challenge test, which indicated that SCO-792 effectively inhibited protein digestion in vivo. In conclusion, our new screen system identified SCO-792 as a potent and reversible inhibitor against enteropeptidase. SCO-792 slowly dissociated from enteropeptidase in vitro and inhibited protein digestion in vivo. Further study using SCO-792 could reveal the effects of inhibiting enteropeptidase on biological actions.
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Enteropeptidasa/antagonistas & inhibidores , Inhibidores Enzimáticos/administración & dosificación , Bibliotecas de Moléculas Pequeñas/administración & dosificación , Administración Oral , Animales , Evaluación Preclínica de Medicamentos , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Transferencia Resonante de Energía de Fluorescencia , Humanos , Concentración 50 Inhibidora , Ratas , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/farmacologíaRESUMEN
The GPR40/FFA1 receptor is a G-protein-coupled receptor expressed in the pancreatic islets and enteroendocrine cells. Here, we report the pharmacological profiles of (3S)-3-cyclopropyl-3-{2-[(1-{2-[(2,2-dimethylpropyl)(6-methylpyridin-2-yl)carbamoyl]-5-methoxyphenyl}piperidin-4-yl)methoxy]pyridin-4-yl}propanoic acid (SCO-267), a novel full agonist of GPR40. Ca2+ signaling and insulin and glucagon-like peptide-1 (GLP-1) secretion were evaluated in GPR40-expressing CHO, MIN6, and GLUTag cells. Hormone secretions and effects on fasting glucose were tested in rats. Single or repeated dosing effects were evaluated in neonatally streptozotocin-induced diabetic rats (N-STZ-1.5 rats), diet-induced obese (DIO) rats, and GPR40-knockout (Ffar1-/- ) mice. Treatment with SCO-267 activated Gq signaling in both high- and low-FFAR1-expressing CHO cells, stimulated insulin secretion in MIN6 cells, and induced GLP-1 release in GLUTag cells. When administered to normal rats, SCO-267 increased insulin, glucagon, GLP-1, glucose-dependent insulinotropic peptide, and peptide YY (PYY) secretions under nonfasting conditions. These results show the full agonistic property of SCO-267 against GPR40. Hypoglycemia was not induced in SCO-267-treated rats during the fasting condition. In diabetic N-STZ-1.5 rats, SCO-267 was highly effective in improving glucose tolerance in single and 2-week dosing studies. DIO rats treated with SCO-267 for 2 weeks showed elevated plasma GLP-1 and PYY levels, reduced food intake, and decreased body weight. In wild-type mice, SCO-267 induced GLP-1 secretion, food intake inhibition, and body weight reduction; however, these effects were abolished in Ffar1-/- mice, indicating a GPR40-dependent mechanism. In conclusion, SCO-267 stimulated islet and gut hormone secretion, improved glycemic control in diabetic rats, and decreased body weight in obese rats. These data suggest the therapeutic potential of SCO-267 for the treatment of diabetes and obesity.
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Glucemia/metabolismo , Peso Corporal/efectos de los fármacos , Ciclopropanos/farmacología , Diabetes Mellitus Experimental/sangre , Diabetes Mellitus Experimental/tratamiento farmacológico , Obesidad/complicaciones , Piperidinas/farmacología , Propionatos/farmacología , Piridinas/farmacología , Receptores Acoplados a Proteínas G/agonistas , Animales , Células CHO , Cricetulus , Ciclopropanos/uso terapéutico , Diabetes Mellitus Experimental/complicaciones , Modelos Animales de Enfermedad , Perros , Ingestión de Alimentos/efectos de los fármacos , Péptido 1 Similar al Glucagón/metabolismo , Humanos , Secreción de Insulina/efectos de los fármacos , Islotes Pancreáticos/efectos de los fármacos , Islotes Pancreáticos/metabolismo , Masculino , Ratones , Piperidinas/uso terapéutico , Propionatos/uso terapéutico , Piridinas/uso terapéutico , RatasRESUMEN
AIMS: Enteropeptidase is a serine protease localized on the duodenal brush border that catalyzes the conversion of inactive trypsinogen into active trypsin, thereby regulating protein breakdown in the gut. We evaluated the effects of SCO-792, a novel enteropeptidase inhibitor, in mice. MATERIALS AND METHODS: In vivo inhibition of enteropeptidase was evaluated via an oral protein challenge. Pharmacological effects were evaluated in normal mice, in diet-induced obese (DIO) mice and in obese and diabetic ob/ob mice. RESULTS: A single oral administration of SCO-792 inhibited plasma branched-chain amino acids (BCAAs) in an oral protein challenge test in mice, indicating in vivo inhibition of enteropeptidase. Repeated treatment with SCO-792 induced reduction in food intake and decrease in body weight in DIO and ob/ob mice. Plasma FGF21 levels were increased in SCO-792-treated DIO mice, an observation that was probably independent of reduction in food intake. Hyperglycaemia was markedly improved in SCO-792-treated ob/ob mice. A hyperinsulinaemic-euglycaemic clamp study revealed improved muscle insulin sensitivity in SCO-792-treated ob/ob mice. SCO-792 also improved plasma and liver lipid profiles and decreased plasma alanine transaminase, suggesting a potential treatment for liver diseases. Dietary supplementation with essential amino acids attenuated the effect of SCO-792 on reduction in food intake and decrease in body weight in normal mice, suggesting a pivotal role for enteropeptidase in these biological phenomena. CONCLUSIONS: SCO-792 inhibited enteropeptidase in vivo, reduced food intake, decreased body weight, increased insulin sensitivity, improved glucose and lipid control, and ameliorated liver parameters in mouse models with obesity and/or diabetes. SCO-792 may exhibit similar effects in patients.
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Diabetes Mellitus Experimental/tratamiento farmacológico , Enteropeptidasa/antagonistas & inhibidores , Obesidad/tratamiento farmacológico , Inhibidores de Serina Proteinasa/farmacología , Bibliotecas de Moléculas Pequeñas/farmacología , Animales , Ácido Aspártico/análogos & derivados , Ácido Aspártico/farmacología , Benzofuranos/farmacología , Glucemia/metabolismo , Peso Corporal/efectos de los fármacos , Diabetes Mellitus Experimental/enzimología , Diabetes Mellitus Experimental/metabolismo , Modelos Animales de Enfermedad , Insulina/sangre , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Obesos , Obesidad/enzimología , Obesidad/metabolismoRESUMEN
Glucagon is the body's main hyperglycemic hormone, and its secretion is dysregulated in type 2 diabetes mellitus (T2DM). The incretin hormone glucagon-like peptide-1 (GLP-1) is released from the gut and is used in T2DM therapy. Uniquely, it both stimulates insulin and inhibits glucagon secretion and thereby lowers plasma glucose levels. In this study, we have investigated the action of GLP-1 on glucagon release from human pancreatic islets. Immunocytochemistry revealed that only <0.5% of the α-cells possess detectable GLP-1R immunoreactivity. Despite this, GLP-1 inhibited glucagon secretion by 50-70%. This was due to a direct effect on α-cells, rather than paracrine signaling, because the inhibition was not reversed by the insulin receptor antagonist S961 or the somatostatin receptor-2 antagonist CYN154806. The inhibitory effect of GLP-1 on glucagon secretion was prevented by the PKA-inhibitor Rp-cAMPS and mimicked by the adenylate cyclase activator forskolin. Electrophysiological measurements revealed that GLP-1 decreased action potential height and depolarized interspike membrane potential. Mathematical modeling suggests both effects could result from inhibition of P/Q-type Ca2+ channels. In agreement with this, GLP-1 and ω-agatoxin (a blocker of P/Q-type channels) inhibited glucagon secretion in islets depolarized by 70 mmol/L [K+ ]o , and these effects were not additive. Intracellular application of cAMP inhibited depolarization-evoked exocytosis in individual α-cells by a PKA-dependent (Rp-cAMPS-sensitive) mechanism. We propose that inhibition of glucagon secretion by GLP-1 involves activation of the few GLP-1 receptors present in the α-cell membrane. The resulting small elevation of cAMP leads to PKA-dependent inhibition of P/Q-type Ca2+ channels and suppression of glucagon exocytosis.
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Canales de Calcio Tipo P/metabolismo , Canales de Calcio Tipo Q/metabolismo , Péptido 1 Similar al Glucagón/farmacología , Células Secretoras de Glucagón/metabolismo , Glucagón/metabolismo , Adulto , Animales , Bloqueadores de los Canales de Calcio/farmacología , Células Cultivadas , Exocitosis , Femenino , Células Secretoras de Glucagón/efectos de los fármacos , Células Secretoras de Glucagón/fisiología , Humanos , Masculino , Potenciales de la Membrana , Ratones , Persona de Mediana EdadRESUMEN
Inositol hexakisphosphate kinase 3 (IP6K3) generates inositol pyrophosphates, which regulate diverse cellular functions. However, little is known about its own physiological role. Here, we show the roles of IP6K3 in metabolic regulation. We detected high levels of both mouse and human IP6K3 mRNA in myotubes and muscle tissues. In human myotubes, IP6K3 was upregulated by dexamethasone treatment, which is known to inhibit glucose metabolism. Furthermore, Ip6k3 expression was elevated under diabetic, fasting, and disuse conditions in mouse skeletal muscles. Ip6k3(-/-) mice demonstrated lower blood glucose, reduced circulating insulin, deceased fat mass, lower body weight, increased plasma lactate, enhanced glucose tolerance, lower glucose during an insulin tolerance test, and reduced muscle Pdk4 expression under normal diet conditions. Notably, Ip6k3 deletion extended animal lifespan with concomitant reduced phosphorylation of S6 ribosomal protein in the heart. In contrast, Ip6k3(-/-) mice showed unchanged skeletal muscle mass and no resistance to the effects of high fat diet. The current observations suggest novel roles of IP6K3 in cellular regulation, which impact metabolic control and lifespan.