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2.
Eur J Pharmacol ; 806: 25-31, 2017 Jul 05.
Article in English | MEDLINE | ID: mdl-28410751

ABSTRACT

Chronic constipation is a highly common functional gastrointestinal disorder that adversely affects patient quality of life. At present, limited therapeutic options are available for the treatment of chronic constipation, which indicates the need for new therapeutic agents. Herein, we report the potential of mizagliflozin, a novel selective sodium glucose co-transporter 1 (SGLT1) inhibitor, for the amelioration of chronic constipation. Mizagliflozin's inhibitory activity against SGLTs was evaluated by an in vitro assay of cells transiently expressing SGLTs. The safety profile of an initial single dose (2-160mg, orally) and multiple doses (2-20mg, orally, once daily immediately prior to breakfast on Days 1 and 13, and three times daily immediately prior to every meal on Days 3-12) of mizagliflozin was determined by performing a phase I study in healthy male subjects. In addition, the effect of mizagliflozin and lubiprostone on fecal wet weight was compared using a dog model of loperamide-induced constipation and rat model of low-fiber-diet-induced constipation. Mizagliflozin potently inhibited human SGLT1 in a highly selective manner. The results of the phase I study showed mizagliflozin increased stool frequency and loosened stool consistency; these effects increased progressively with an increase in the dosage and the number of doses of mizagliflozin. In addition, the oral administration of mizagliflozin increased fecal wet weight in a dog model of loperamide-induced constipation and a rat model of low-fiber-diet-induced constipation, similar to lubiprostone. These results suggest the potential use of a novel selective SGLT1 inhibitor, mizagliflozin, for the amelioration of chronic constipation.


Subject(s)
Amides/pharmacology , Constipation/drug therapy , Glucosides/pharmacology , Pyrazoles/pharmacology , Sodium-Glucose Transporter 1/antagonists & inhibitors , Amides/therapeutic use , Animals , Chronic Disease/drug therapy , Clinical Trials, Phase I as Topic , Constipation/chemically induced , Dietary Fiber/pharmacology , Dogs , Dose-Response Relationship, Drug , Glucosides/therapeutic use , Humans , Loperamide/pharmacology , Male , Pyrazoles/therapeutic use , Rats
3.
J Med Chem ; 59(8): 3719-31, 2016 04 28.
Article in English | MEDLINE | ID: mdl-27007871

ABSTRACT

To test the hypothesis that inhibitors of human concentrative nucleoside transporter 2 (hCNT2) suppress increases in serum urate levels derived from dietary purines, we previously identified adenosine derivative 1 as a potent hCNT2 inhibitor (IC50 = 0.64 µM), but further study was hampered due to its poor solubility. Here we describe the results of subsequent research to identify more soluble and more potent hCNT2 inhibitors, leading to the discovery of the benzimidazole nucleoside 22, which is the most potent hCNT2 inhibitor (IC50 = 0.062 µM) reported to date. Compound 22 significantly suppressed the increase in plasma uric acid levels after oral administration of purine nucleosides in rats. Because compound 22 was poorly absorbed orally in rats (F = 0.51%), its pharmacologic action was mostly limited to the gastrointestinal tract. These findings suggest that inhibition of hCNT2 in the gastrointestinal tract can be a promising approach for the treatment of hyperuricemia.


Subject(s)
Adenine/chemistry , Benzimidazoles/chemistry , Gout/drug therapy , Hyperuricemia/drug therapy , Membrane Transport Proteins/drug effects , Nucleosides/pharmacology , Animals , Humans , Male , Nucleosides/chemistry , Nucleosides/pharmacokinetics , Nucleosides/therapeutic use , Rats , Rats, Sprague-Dawley
4.
J Clin Exp Hepatol ; 5(3): 190-8, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26628836

ABSTRACT

BACKGROUND: Nonalcoholic fatty liver disease and nonalcoholic steatohepatitis (NASH) are serious conditions and are being diagnosed at an increased rate. The etiology of these hepatic disorders is not clear but involves insulin resistance and oxidative stress. Remogliflozin etabonate (Remo) is an inhibitor of the sodium glucose-dependent renal transporter 2 (SGLT2), and improves insulin sensitivity in type 2 diabetics. In the current study, we examined the effects of Remo in a diet-induced obese mouse model of NAFLD. METHODS: After 11-weeks on High-Fat-Diet 32 (HFD32), C57BL/6J mice were obese and displayed characteristics consistent with NAFLD. Cohorts of obese animals were continued on HFD32 for an additional 4-week treatment period with or without Remo. RESULTS: Treatment with Remo for 4 weeks markedly lowered both plasma alanine aminotransferase (76%) and aspartate aminotransferase (48%), and reduced both liver weight and hepatic triglyceride content by 42% and 40%, respectively. Remo also reduced hepatic mRNA content for tumor necrosis factor (TNF)-α (69%), and monocyte chemoattractant protein (MCP)-1 (69%). The diet-induced increase in thiobarbituric acid-reactive substances, a marker of oxidative stress, was reduced following treatment with Remo, as measured in both liver homogenates (22%) and serum (37%). Finally, the oxygen radical absorbance capacity (ORAC) in three different SGLT2 inhibitors was determined: remogliflozin, canagliflozin and dapagliflozin. Only remogliflozin had any significant ORAC activity. CONCLUSIONS: Remo significantly improved markers associated with NAFLD in this animal model, and may be an effective compound for the treatment of NASH and NAFLD due to its insulin-sensitizing and antioxidant properties.

5.
ACS Med Chem Lett ; 6(3): 244-8, 2015 Mar 12.
Article in English | MEDLINE | ID: mdl-25815140

ABSTRACT

Purine-rich foods have long been suspected as a major cause of hyperuricemia. We hypothesized that inhibition of human concentrative nucleoside transporter 2 (hCNT2) would suppress increases in serum urate levels derived from dietary purines. To test this hypothesis, the development of potent hCNT2 inhibitors was required. By modifying adenosine, an hCNT2 substrate, we successfully identified 8-aminoadenosine derivatives as a new class of hCNT2 inhibitors. Compound 12 moderately inhibited hCNT2 (IC50 = 52 ± 3.8 µM), and subsequent structure-activity relationship studies led to the discovery of compound 48 (IC50 = 0.64 ± 0.19 µM). Here we describe significant findings about structural requirements of 8-aminoadenosine derivatives for exhibiting potent hCNT2 inhibitory activity.

6.
Biol Pharm Bull ; 37(7): 1168-76, 2014.
Article in English | MEDLINE | ID: mdl-24989008

ABSTRACT

Phlorizin is a type of flavonoids and has a peroxynitrite scavenging effect. This study aimed to elucidate the effects of phlorizin on ischemia-induced ventricular tachyarrhythmia (VT). Optical signals from the epicardial surface of the ventricle or left ventricular end diastolic pressure (LVEDP) were recorded during acute global ischemia in 42 Langendorff-perfused guinea pig hearts. Experiments were performed in the control condition and in the presence of phlorizin or N-2-mercaptopropionylglycine (2-MPG), a peroxynitrite scavenger, respectively. Mean action potential duration at 20 min of ischemia did not differ among the three interventions. Impulse conduction time-dependently slowed during 20 min of ischemia in the control. Phlorizin but not 2-MPG improved the ischemic conduction slowing at 15 and 20 min of ischemia. Programmed stimulation induced VT at 20 min of ischemia in the control and in the presence of 2-MPG but not in the presence of phlorizin (p<0.05). LVEDP was increased during 30 min of ischemia in the control and in the presence of 2-MPG but not in the presence of phlorizin. These results indicate that phlorizin prevents VT through the improvement of impulse conduction slowing during ischemia. Phlorizin may be more useful for ischemia-induced VT than 2-MPG.


Subject(s)
Anti-Arrhythmia Agents/therapeutic use , Myocardial Ischemia/complications , Phlorhizin/therapeutic use , Tachycardia, Ventricular/prevention & control , Action Potentials/drug effects , Animals , Anti-Arrhythmia Agents/administration & dosage , Blood Pressure/drug effects , Calcium/metabolism , Electric Stimulation , Electrocardiography , Electrodes , Guinea Pigs , Heart Conduction System/drug effects , Myocardial Ischemia/metabolism , Myocardial Ischemia/physiopathology , Perfusion , Phlorhizin/administration & dosage , Tachycardia, Ventricular/etiology , Tachycardia, Ventricular/metabolism , Tachycardia, Ventricular/physiopathology , Ventricular Function, Left/drug effects , Voltage-Sensitive Dye Imaging
7.
Bioorg Med Chem ; 21(3): 748-65, 2013 Feb 01.
Article in English | MEDLINE | ID: mdl-23273606

ABSTRACT

Sodium glucose co-transporter 1 (SGLT1) plays a dominant role in the absorption of glucose in the gut and is considered a promising target in the development of therapeutic options for postprandial hyperglycemia. Previously, we reported potent and selective SGLT1 inhibitors 1 and 2 showing efficacy in oral carbohydrate tolerance tests in diabetic rat models. In a pharmacokinetic (PK) study of 2, excessive systemic exposure to metabolites of 2 was observed, presumably due to the high permeability of its aglycone (2a). To further improve SGLT1 inhibitory activity and reduce aglycone permeability, a series of 4-benzyl-5-isopropyl-1H-pyrazol-3-yl ß-D-glycopyranoside derivatives bearing novel hydrophilic substitution groups on the phenyl ring were synthesized and their inhibitory activity toward SGLTs was evaluated. Optimized compound 14c showed an improved profile satisfying both higher activity and lower permeability of its aglycone (22f) compared with initial leads 1 and 2. Moreover, the superior efficacy of 14c in various carbohydrate tolerance tests in diabetic rat models was confirmed compared with acarbose, an α-glucosidase inhibitor (α-GI) widely used in the clinic.


Subject(s)
Drug Design , Glycosides/pharmacology , Sodium-Glucose Transporter 1/antagonists & inhibitors , Dose-Response Relationship, Drug , Glycosides/chemical synthesis , Glycosides/chemistry , Humans , Hydrophobic and Hydrophilic Interactions , Molecular Structure , Structure-Activity Relationship
8.
Bioorg Med Chem ; 20(22): 6598-612, 2012 Nov 15.
Article in English | MEDLINE | ID: mdl-23062824

ABSTRACT

Sodium glucose co-transporter 1 (SGLT1) plays a dominant role in the absorption of glucose in the gut and is considered a promising target in the development of treatments for postprandial hyperglycemia. A series of 4-benzyl-1H-pyrazol-3-yl ß-d-glucopyranoside derivatives have been synthesized, and its inhibitory activity toward SGLTs has been evaluated. By altering the substitution groups at the 5-position of the pyrazole ring, and every position of the phenyl ring, we studied the structure-activity relationship (SAR) profiles and identified a series of potent and selective SGLT1 inhibitors. Representative derivatives showed a dose-dependent suppressing effect on the escalation of blood glucose levels in oral mixed carbohydrate tolerance tests (OCTT) in streptozotocin-nicotinamide-induced diabetic rats (NA-STZ rats).


Subject(s)
Glucosides/chemistry , Hypoglycemic Agents/chemical synthesis , Sodium-Glucose Transporter 1/antagonists & inhibitors , Animals , Blood Glucose/analysis , Crystallography, X-Ray , Diabetes Mellitus, Experimental/drug therapy , Glucosides/chemical synthesis , Glucosides/therapeutic use , Humans , Hyperglycemia/drug therapy , Hypoglycemic Agents/chemistry , Hypoglycemic Agents/therapeutic use , Molecular Conformation , Rats , Sodium-Glucose Transporter 1/metabolism , Sodium-Glucose Transporter 2/metabolism , Sodium-Glucose Transporter 2 Inhibitors , Structure-Activity Relationship
9.
Eur J Pharmacol ; 690(1-3): 183-91, 2012 Sep 05.
Article in English | MEDLINE | ID: mdl-22709993

ABSTRACT

We have developed concentrative nucleoside transporter 2 (CNT2) inhibitors as a novel pharmacological approach for improving hyperuricemia by inhibiting intestinal absorption of purines. Dietary purine nucleosides are absorbed in the small intestines by CNTs expressed in the apical membrane. In humans, the absorbed purine nucleosides are rapidly degraded to their final end product, uric acid, by xanthine oxidase. Based on the expression profile of human CNTs in digestive tract tissues, we established a working hypothesis that mainly CNT2 contributes to the intestinal absorption of purine nucleosides. In order to confirm this possibility, we developed CNT2 inhibitors and found that (2R,3R,4S,5R)-2-(6-amino-8-{[3'-(3-aminopropoxy)-biphenyl-4-ylmethyl]-amino}-9H-purin-9-yl)-5-hydroxymethyl-tetrahydrofuran-3,4-diol (KGO-2142) and 1-[3-(5-{[1-((2R,3R,4S,5R)-3,4-dihydroxy-5-hydroxymethyl-tetrahydrofuran-2-yl)-1H-benzimidazol-2-ylamino]-methyl}-2-ethoxyphenoxy)-propyl]-piperidine-4-carboxylic acid amide (KGO-2173) were inhibitory. These CNT2 inhibitors had potent inhibitory activity against inosine uptake via human CNT2, but they did not potently interfere with nucleoside uptake via human CNT1, CNT3 or equilibrative nucleoside transporters (ENTs) in vitro. After oral administration of KGO-2173 along with [(14)C]-inosine, KGO-2173 significantly decreased the urinary excretion of radioactivity at 6 and 24h in rats. Since dietary purine nucleosides are not utilized in the body and are excreted into the urine rapidly, this decrease in radioactivity in the urine represented the inhibitory activity of KGO-2173 toward the absorption of [(14)C]-inosine in the small intestines. KGO-2142 almost completely inhibited dietary RNA-induced hyperuricemia and the increase in urinary excretion of uric acid in cebus monkeys. These novel CNT2 inhibitors, KGO-2142 and KGO-2173, could be useful therapeutic options for the treatment of hyperuricemia.


Subject(s)
Furans/pharmacology , Intestinal Absorption/drug effects , Membrane Transport Proteins/metabolism , Purine Nucleosides/metabolism , Renal Tubular Transport, Inborn Errors/drug therapy , Renal Tubular Transport, Inborn Errors/metabolism , Urinary Calculi/drug therapy , Urinary Calculi/metabolism , Animals , Biological Transport/drug effects , COS Cells , Cebus , Chlorocebus aethiops , Dose-Response Relationship, Drug , Furans/chemistry , Furans/therapeutic use , Gene Expression Regulation/drug effects , HeLa Cells , Humans , Inosine/metabolism , Male , RNA, Fungal/administration & dosage , RNA, Fungal/pharmacology , Rats , Rats, Sprague-Dawley , Renal Tubular Transport, Inborn Errors/blood , Uric Acid/blood , Urinary Calculi/blood
10.
J Pharmacol Exp Ther ; 342(2): 288-96, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22537769

ABSTRACT

The high-affinity sodium glucose cotransporter (SGLT1) plays a critical role in glucose absorption from the gastrointestinal tract. We have developed 3-(3-{4-[3-(ß-D-glucopyranosyloxy)-5-isopropyl-1H-pyrazol-4-ylmethyl]-3-methylphenoxy}propylamino)propionamide (KGA-2727), which has a pyrazole-O-glucoside structure, as the first selective SGLT1 inhibitor. KGA-2727 inhibited SGLT1 potently and highly selectively in an in vitro assay using cells transiently expressing recombinant SGLTs. In a small intestine closed loop absorption test with normal rats, KGA-2727 inhibited the absorption of glucose but not that of fructose. After oral intake of starch along with KGA-2727 in normal rats, the residual content of glucose in the gastrointestinal tract increased. In the oral glucose tolerance test with streptozotocin-induced diabetic rats, KGA-2727 attenuated the elevation of plasma glucose after glucose loading, indicating that KGA-2727 improved postprandial hyperglycemia. In Zucker diabetic fatty (ZDF) rats, chronic treatments with KGA-2727 reduced the levels of plasma glucose and glycated hemoglobin. Furthermore, KGA-2727 preserved glucose-stimulated insulin secretion and reduced urinary glucose excretion with improved morphological changes of pancreatic islets and renal distal tubules in ZDF rats. In addition, the chronic treatment with KGA-2727 increased the level of glucagon-like peptide-1 in the portal vein. Taken together, our data indicate that the selective SGLT1 inhibitor KGA-2727 had antidiabetic efficacy and allow us to propose KGA-2727 as a candidate for a novel and useful antidiabetic agent.


Subject(s)
Diabetes Mellitus, Experimental/drug therapy , Glucosides/pharmacology , Hypoglycemic Agents/pharmacology , Pyrazoles/pharmacology , Sodium-Glucose Transporter 1/antagonists & inhibitors , Animals , Diabetes Mellitus, Experimental/metabolism , Glucagon-Like Peptide 1/metabolism , Glucose/metabolism , Glucosides/metabolism , Glycated Hemoglobin/metabolism , Humans , Hyperglycemia/drug therapy , Hyperglycemia/metabolism , Hypoglycemic Agents/chemistry , Insulin/metabolism , Intestinal Absorption/drug effects , Intestine, Small/drug effects , Intestine, Small/metabolism , Islets of Langerhans/drug effects , Islets of Langerhans/metabolism , Male , Rats , Rats, Wistar , Rats, Zucker , Sodium-Glucose Transporter 1/metabolism
11.
Kidney Int Suppl ; (120): S14-9, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21358697

ABSTRACT

The physiological and pathological handling of glucose via sodium-glucose cotransporter-2 (SGLT2) in the kidneys has been evolving, and SGLT2 inhibitors have been focused upon as a novel drug for treating diabetes. SGLT2 inhibitors enhance renal glucose excretion by inhibiting renal glucose reabsorption. Consequently, SGLT2 inhibitors reduce plasma glucose insulin independently and improve insulin resistance in diabetes. To date, various SGLT2 inhibitors have been developed and evaluated in clinical studies. The potency and positioning of SGLT2 inhibitors as an antidiabetic drug are dependent on their characteristic profile, which induces selectivity, efficacy, pharmacokinetics, and safety. This profile decides which SGLT2 inhibitors can be expected for application of the theoretical concept of reducing renal glucose reabsorption for the treatment of diabetes. I review the structure and advancing profile of various SGLT2 inhibitors, comparing their similarities and differences, and discuss the expected SGLT2 inhibitors for an emerging category of antidiabetic drugs.


Subject(s)
Hypoglycemic Agents/chemistry , Hypoglycemic Agents/pharmacology , Kidney/drug effects , Sodium-Glucose Transporter 2 Inhibitors , Sodium-Glucose Transporter 2/drug effects , Diabetes Mellitus, Type 2/drug therapy , Drug Design , Humans , Hypoglycemic Agents/therapeutic use , Insulin Resistance
12.
Endocr Res ; 35(4): 174-82, 2010.
Article in English | MEDLINE | ID: mdl-20722489

ABSTRACT

INTRODUCTION: The effect of beta3-adrenergic receptor agonists on beta cells in the islets of Langerhans is not yet clear. This study examined the beta3-adrenergic receptor agonist on beta cells in the islets of Langerhans. METHODS: Obese diabetic C57BL/KsJ-db/db mice were treated with KTO-7924, a newly-developed beta3-adrenergic receptor agonist for 28-day. We analyzed plasma parameters, insulin resistance, and insulin-positive areas among beta-cells in the islets of Langerhans. RESULTS AND CONCLUSION: After a 28-day oral administration period, plasma levels of hemoglobin (Hb) A1c, glucose, triglyceride (TG), and free fatty acid (FFA) were all significantly reduced in KTO-7924 treatment groups compared with controls. Plasma adiponectin levels decreased with age in the control group, but were significantly higher in a treatment group throughout the study period. Furthermore, sequential administration of KTO-7924 led to an improvement in insulin resistance in the OGTT (Oral glucose tolerance test (OGTT)), and an increase in the percentage of insulin-positive areas among beta-cells in the islets of Langerhans compared with controls. This is the first study to show islet histology after treatment of a beta3-adrenergic receptor agonist, and reveals that KTO-7924 reduces hyperglycemia, and protects beta-cells in the islets of Langerhans of db/db mice.


Subject(s)
Adrenergic Agonists/pharmacology , Hyperglycemia/blood , Hyperglycemia/drug therapy , Insulin-Secreting Cells/drug effects , Adiponectin/blood , Adiponectin/genetics , Animals , Blood Glucose/metabolism , Fatty Acids, Nonesterified/blood , Glucose Tolerance Test , Glycated Hemoglobin/metabolism , Hyperglycemia/pathology , Insulin/blood , Male , Mice , Mice, Inbred C57BL , Mice, Obese , RNA/chemistry , RNA/genetics , Reverse Transcriptase Polymerase Chain Reaction , Triglycerides/blood
13.
Eur J Pharmacol ; 618(1-3): 98-104, 2009 Sep 15.
Article in English | MEDLINE | ID: mdl-19615995

ABSTRACT

Sergliflozin etabonate, a novel oral selective low-affinity sodium glucose cotransporter (SGLT2) inhibitor, improves hyperglycemia by suppressing renal glucose reabsorption, in which SGLT2 participates as a dominant transporter. In the present study, we examined the antidiabetic profile of sergliflozin etabonate in a diabetic model, KK-A(y) mice, with symptoms of obesity and hyperinsulinemia. The blood glucose level was monitored in non-fasted female KK-A(y) mice after a single oral administration of sergliflozin etabonate. The non-fasting blood glucose level was reduced in a dose-dependent manner after a single oral administration of sergliflozin etabonate (39% reduction at 2 h after a dose of 30 mg/kg). The effects of long-term administration of sergliflozin etabonate on the blood glucose level were assessed in female KK-A(y) mice in several studies (4-day, 8-week, and 9-week administration study), in which sergliflozin etabonate was administered in the diet. The non-fasting blood glucose and plasma insulin were both lowered dose-dependently in the 4-day administration study. Long-term treatment with sergliflozin etabonate dose-dependently improved the hyperglycemia and prevented body weight gain in the 8-week study. In addition to the improvement in glycemic control, fatty liver and pancreatic beta-cell abnormalities were ameliorated in mice fed sergliflozin etabonate in the 9-week study. These data indicate that SGLT2 inhibitors could be useful to improve hyperglycemia resulting from insulin resistance without pancreatic beta-cell abuse or body weight gain. SGLT2 inhibitors may simultaneously realize both a systemic negative energy balance and correction of hyperglycemia.


Subject(s)
Benzhydryl Compounds/administration & dosage , Benzhydryl Compounds/pharmacology , Glucose/metabolism , Glucosides/administration & dosage , Glucosides/pharmacology , Hypoglycemic Agents/administration & dosage , Hypoglycemic Agents/pharmacology , Administration, Oral , Animals , Benzhydryl Compounds/therapeutic use , Drug Administration Schedule , Female , Glucosides/therapeutic use , Hyperinsulinism/complications , Hyperinsulinism/drug therapy , Hyperinsulinism/metabolism , Hypoglycemic Agents/therapeutic use , Mice , Mice, Inbred Strains , Obesity/complications , Obesity/drug therapy , Obesity/metabolism , Time Factors
14.
Eur J Pharmacol ; 609(1-3): 148-54, 2009 May 01.
Article in English | MEDLINE | ID: mdl-19281809

ABSTRACT

The low-affinity sodium glucose cotransporter (SGLT2) is responsible for most of the glucose reabsorption in the kidney and has been highlighted as a novel therapeutic target for the treatment of diabetes. We discovered sergliflozin etabonate, a novel selective SGLT2 inhibitor, and found that selective inhibition of SGLT2 increased urinary glucose excretion and consequently decreased plasma glucose levels. In this report, we examined the antihyperglycemic effects of sergliflozin etabonate in normal and diabetic rats in comparison with those of a sulfonylurea (gliclazide) and an alpha-glucosidase inhibitor (voglibose). Sergliflozin etabonate increased urinary glucose excretion in a dose-dependent manner, and inhibited the increase in plasma glucose after sucrose loading independently of insulin secretion in normal rats. Sergliflozin etabonate also improved postprandial hyperglycemia in neonatal streptozotocin-induced diabetic rats; whereas gliclazide did not improve it. In rats with mild or moderate streptozotocin-induced diabetes, the degree of the antihyperglycemic effects of sergliflozin etabonate correlated with the severity of the diabetic condition. Sergliflozin etabonate did not affect the plasma glucose level of normal rats as seen with gliclazide. Chronic treatment with sergliflozin etabonate reduced the levels of glycated hemoglobin and fasting plasma glucose, and improved the glycemic response after glucose loading in Zucker fatty rats. In addition, sergliflozin etabonate did not affect the body weight or food intake. These data indicate that sergliflozin etabonate could improve glycemic control without its use resulting in insulin secretion, hypoglycemia, and body weight gain, and may provide a unique approach to the treatment of diabetes.


Subject(s)
Diabetes Mellitus, Experimental/drug therapy , Glucosides/pharmacology , Hypoglycemic Agents/pharmacology , Sodium-Glucose Transporter 2 Inhibitors , Animals , Area Under Curve , Blood Glucose/analysis , Diabetes Mellitus, Experimental/blood , Dose-Response Relationship, Drug , Fasting , Glucose Tolerance Test , Glucosides/adverse effects , Glycated Hemoglobin/analysis , Glycosuria/chemically induced , Hypoglycemic Agents/adverse effects , Insulin/blood , Insulin/metabolism , Kinetics , Male , Rats , Rats, Zucker , Sodium-Glucose Transporter 2/physiology , Streptozocin/pharmacology
15.
Bioorg Med Chem ; 17(1): 284-94, 2009 Jan 01.
Article in English | MEDLINE | ID: mdl-19010686

ABSTRACT

Zeta-associated protein, 70 kDa (ZAP-70), a spleen tyrosine kinase (Syk) family kinase, is normally expressed on T cells and natural killer cells and plays a crucial role in activation of the T cell immunoresponse. Thus, selective ZAP-70 inhibitors might be useful not only for treating autoimmune diseases, but also for suppressing organ transplant rejection. In our recent study on the synthesis of Syk family kinase inhibitors, we discovered that novel imidazo[1,2-c]pyrimidine-8-carboxamide derivatives possessed potent ZAP-70 inhibitory activity with good selectivity for ZAP-70 over other kinases. In particular, compound 26 showed excellent ZAP-70 kinase inhibition and high selectivity for ZAP-70 over structurally related Syk. The discovery of a potent, highly selective ZAP-70 inhibitor would contribute a new therapeutic tool for autoimmune diseases and organ transplant medication.


Subject(s)
Protein Kinase Inhibitors/chemical synthesis , Pyrimidines/chemical synthesis , Pyrimidines/pharmacology , ZAP-70 Protein-Tyrosine Kinase/antagonists & inhibitors , Amides , Benzene Derivatives , Humans , Immunity , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Structure-Activity Relationship , ZAP-70 Protein-Tyrosine Kinase/immunology
16.
J Struct Biol ; 165(3): 133-9, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19111934

ABSTRACT

Catechol-O-methyltransferase (COMT, EC 2.1.1.6) is a monomeric enzyme that catalyzes the transfer of a methyl group from S-adenosyl-l-methionine (AdoMet) to the phenolic oxygen of substituted catechols. Although the inhibitor recognition pattern and AdoMet site have already been studied crystallographically, structural information on the catalytic cycle of COMT has not yet been obtained. In this study, comparison of the co-factor and inhibitor-bound structures revealed that the Apo form of COMT shows a conformational change and there was no cleft corresponding to the AdoMet-binding site; the overall structure was partially open form and the substrate recognition site was not clearly defined. The Holo form of COMT was similar to the quaternary structure except for the beta6-beta7 and alpha2-alpha3 ligand recognition loops. These conformational changes provide a deeper insight into the structural events occurring in reactions catalyzed by AdoMet.


Subject(s)
Catechol O-Methyltransferase/chemistry , Animals , Apoenzymes/chemistry , Binding Sites , Catalytic Domain , Catechols/chemistry , Crystallography, X-Ray , Holoenzymes/chemistry , Hydrogen Bonding , Hydrophobic and Hydrophilic Interactions , Magnesium/chemistry , Models, Molecular , Protein Conformation , Rats , Recombinant Proteins/chemistry , S-Adenosylmethionine/chemistry
17.
Bioorg Med Chem ; 16(20): 9247-60, 2008 Oct 15.
Article in English | MEDLINE | ID: mdl-18823784

ABSTRACT

Spleen tyrosine kinase (Syk) and zeta-associated protein kinase of 70k Da (ZAP-70) are members of the Syk family and non-receptor-type protein tyrosine kinases, which play crucial roles in B- and T-cell activation. Therefore, a Syk family tyrosine kinases inhibitor would be a useful therapeutic agent for the treatment of various allergic disorders and autoimmune diseases. Previously, we reported that 1,2,4-triazolo[4,3-c]pyrimidine derivative 1 and 1,2,4-triazolo[1,5-c]pyrimidine derivative 2 showed strong inhibitory activities against Syk family kinases. These compounds also exhibited high-level suppression of IL-2 in cellular assays. However, their oral efficacies were poor in a mouse model of IL-2 production. To improve oral effectiveness, we investigated a new series of Syk family kinases inhibitors. We found that imidazo[1,2-c]pyrimidine derivatives potently inhibited the Syk family kinases. Among these agents, compound 9f not only showed strong inhibitory activities against Syk and ZAP-70 kinases in vitro, but its oral administration resulted in the in vivo suppression of both the passive cutaneous anaphylaxis reaction and Concanavalin A-induced IL-2 production in a mouse model.


Subject(s)
Imidazoles/chemistry , Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Protein Kinase Inhibitors/administration & dosage , Protein Kinase Inhibitors/chemical synthesis , Protein-Tyrosine Kinases/antagonists & inhibitors , Pyrimidines/administration & dosage , Pyrimidines/chemical synthesis , Administration, Oral , Animals , Crystallography, X-Ray , Enzyme Activation/drug effects , Humans , Inhibitory Concentration 50 , Intracellular Signaling Peptides and Proteins/classification , Intracellular Signaling Peptides and Proteins/metabolism , Mice , Mice, Inbred ICR , Models, Molecular , Molecular Structure , Protein Kinase Inhibitors/chemistry , Protein-Tyrosine Kinases/classification , Protein-Tyrosine Kinases/metabolism , Pyrimidines/chemistry , Structure-Activity Relationship , Syk Kinase , ZAP-70 Protein-Tyrosine Kinase/antagonists & inhibitors , ZAP-70 Protein-Tyrosine Kinase/metabolism
18.
Bioorg Med Chem ; 16(15): 7347-57, 2008 Aug 01.
Article in English | MEDLINE | ID: mdl-18585046

ABSTRACT

Splenic tyrosine kinase (Syk) family kinases, which are members of the protein tyrosine kinase family, play crucial roles in immune responses, with Syk participating in B-cell activation and the zeta-associated protein 70 kDa (ZAP-70) kinase being involved in T-cell activation. Therefore, Syk family kinase inhibitors are candidate therapeutic agents for the treatment of various allergic disorders and autoimmune diseases. We designed 1,2,4-triazolo[4,3-c]pyrimidine and 1,2,4-triazolo[1,5-c]pyrimidine derivatives as Syk family kinase inhibitors, based on literature reports and structure-based drug design. These derivatives showed significant Syk inhibitory activities, with ZAP-70 inhibition. Representative compounds 10d and 11 not only exhibited strong inhibition of both Syk and ZAP-70 kinase but also suppressed IL-2 production by peripheral blood mononuclear cells and whole blood.


Subject(s)
Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Protein-Tyrosine Kinases/antagonists & inhibitors , Pyrimidines/chemistry , Pyrimidines/pharmacology , Binding Sites , Drug Design , Humans , Interleukin-1/metabolism , Leukocytes/drug effects , Leukocytes/metabolism , Models, Molecular , Molecular Structure , Structure-Activity Relationship , Syk Kinase
19.
J Pharmacol Exp Ther ; 327(1): 268-76, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18583547

ABSTRACT

The low-affinity sodium glucose cotransporter (SGLT2) plays an important role in renal glucose reabsorption and is a remarkable transporter as a molecular target for the treatment of diabetes. We have discovered remogliflozin etabonate, which is a novel category of selective SGLT2 inhibitors. Remogliflozin etabonate is a prodrug based on benzylpyrazole glucoside and is metabolized to its active form, remogliflozin, in the body. We identified remogliflozin to be a potent and highly selective SGLT2 inhibitor by examining COS-7 cells transiently expressing either high-affinity sodium glucose cotransporter (SGLT1) or SGLT2. Orally administered remogliflozin etabonate increased urinary glucose excretion in a dose-dependent manner in both mice and rats. By increasing urinary glucose excretion, remogliflozin etabonate inhibited the increase in plasma glucose after glucose loading without stimulating insulin secretion in normal rats. Remogliflozin etabonate also showed antihyperglycemic effects in both streptozotocin-induced diabetic rats in oral glucose tolerance and in db/db mice in the fed condition. Chronic treatment with remogliflozin etabonate reduced the levels of fasting plasma glucose and glycated hemoglobin, and it ameliorated glucosuria in db/db mice. In high-fat diet-fed Goto-Kakizaki rats, remogliflozin etabonate improved hyperglycemia, hyperinsulinemia, hypertriglyceridemia, and insulin resistance. This study demonstrates that treatment with remogliflozin etabonate exhibits antidiabetic efficacy in several rodent models and suggests that remogliflozin etabonate may be a new and useful drug for the treatment of diabetes.


Subject(s)
Glucosides/pharmacology , Hypoglycemic Agents/pharmacology , Pyrazoles/pharmacology , Sodium-Glucose Transporter 2 Inhibitors , Animals , COS Cells , Chlorocebus aethiops , Disease Models, Animal , Dose-Response Relationship, Drug , Female , Glucose Tolerance Test , Glycosuria/chemically induced , Humans , Insulin Resistance , Male , Mice , Mice, Inbred C57BL , Rats , Rats, Sprague-Dawley , Rats, Wistar , Sodium-Glucose Transporter 2
20.
Curr Opin Investig Drugs ; 8(4): 285-92, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17458177

ABSTRACT

In the search for potential new drug targets for the treatment of diabetes, sodium-glucose cotransporters (SGLTs), in particular SGLT2, have been the subject of particular attention. SGLT2 plays an important role in glucose reabsorption in the kidney, and SGLT2 inhibitors enhance renal glucose excretion and consequently lower plasma glucose levels. Thus, SGLT2 inhibitors can control energy balance in a negative direction. The principle behind SGLT2 inhibition involves the improvement of diabetic conditions without increasing body weight or the risk of hypoglycemia. A number of pharmaceutical companies are evaluating SGLT2 inhibitors, and studies have confirmed the therapeutic potency and safety of these drugs for the potential treatment of diabetes.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Hypoglycemic Agents/therapeutic use , Sodium-Glucose Transport Proteins/antagonists & inhibitors , Animals , Carbonates/chemistry , Carbonates/therapeutic use , Clinical Trials, Phase II as Topic , Diabetes Mellitus, Type 2/metabolism , Glucosides/chemistry , Glucosides/therapeutic use , Humans , Hypoglycemic Agents/chemistry , Molecular Structure
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