Project description:Insulin secretagogues are used for treatment of type 2 diabetes. We attempted to discover novel small molecules to stimulate insulin secretion by using in silico similarity search using sulfonylureas as query, followed by measurement of insulin secretion. Among 38 compounds selected by in silico similarity search, we found three diphenylsemicarbazides and one quinolone that stimulate insulin secretion. We focused on compound 8 (C8), which had the strongest insulin-secreting effect. Based on the structure-activity relationship of C8-derivatives, we identified diphenylthiosemicarbazide (DSC) 108 as the most potent secretagogue. DSC108 increased the intracellular Ca2+ level in MIN6-K8 cells. Competitive inhibition experiment and electrophysiological analysis revealed sulfonylurea receptor 1 (SUR1) to be the target of DSC108 and that this diphenylthiosemicarbazide directly inhibits ATP-sensitive K+ (KATP) channels. Pharmacokinetic analysis showed that DSC108 has a short half-life in vivo. Oral administration of DSC108 significantly suppressed the rises in blood glucose levels after glucose load in wild-type mice and improved glucose tolerance in the Goto-Kakizaki (GK) rat, a model of type 2 diabetes with impaired insulin secretion. Our data indicate that DSC108 is a novel insulin secretagogue, and is a lead compound for development of a new anti-diabetic agent.
Project description:Dinucleoside polyphosphates exert their physiological effects via P2 receptors (P2Rs). They are attractive drug candidates, as they offer better stability and specificity compared to nucleotides, the most common P2 receptor ligands. The activation of pancreatic P2Y receptors by nucleotides increases insulin secretion. Therefore, in the current study, dinucleoside polyphosphate analogues (di-(2-MeS)-adenosine-5',5''-P(1),P(4),alpha,beta-methylene-tetraphosphate), 8, (di-(2-MeS)-adenosine-5',5''-P(1),P(4),beta,gamma-methylene-tetraphosphate), 9, and di-(2-MeS)-adenosine-5',5''-P(1),P(3),alpha,beta-methylene triphosphate, 10, were developed as potential insulin secretagogues. Analogues 8 and 9 were found to be agonists of the P2Y(1)R with EC(50) values of 0.42 and 0.46 microM, respectively, whereas analogue 10 had no activity. Analogues 8-10 were found to be completely resistant to hydrolysis by alkaline phosphatase over 3 h at 37 degrees C. Analogue 8 also was found to be 2.5-fold more stable in human blood serum than ATP, with a half-life of 12.1 h. Analogue 8 administration in rats caused a decrease in a blood glucose load from 155 mg/dL to ca. 100 mg/dL and increased blood insulin levels 4-fold as compared to basal levels. In addition, analogue 8 reduced a blood glucose load to normal values (80-110 mg/dL), unlike the commonly prescribed glibenclamide, which reduced glucose levels below normal values (60 mg/dL). These findings suggest that analogue 8 may prove to be an effective and safe treatment for type 2 diabetes.
Project description:The mechanisms underlying Roux-en-Y gastric bypass (RYGB) surgery-induced weight loss and the immediate postoperative beneficial metabolic effects associated with the operation remain uncertain. We aimed to identify novel gut-derived peptides with therapeutic potential in obesity and/or diabetes by determining genome-wide expression patterns in isolated human small intestinal enteroendocrine cells (EECs) obtained from 20 obese subjects undergoing RYGB and again three months later by upper enteroscopy. RYGB increased expression levels of the inverse ghrelin receptor agonist, liver-enriched antimicrobial peptide 2 (LEAP2), and a secreted endogenous LEAP2 fragment (LEAP238-47) demonstrated insulinotropic properties in vitro, promoting an increase in insulin release comparable to the gut hormone glucagon-like peptide 1. LEAP238-47 showed reciprocal effects on growth hormone secretagogue receptor (GHSR) activity, suggesting that the insulinotropic action of the peptide may be directly linked to attenuation of tonic GHSR activity. The fragment was infused to healthy human individuals, but compared to placebo, no glucoregulatory effect was observed in the chosen dose. In conclusion, small intestinal LEAP2 expression was upregulated after RYGB; and the fragment LEAP238-47 showed a strong in vitro insulinotropic effect, but failed to elicit glucoregulatory effects when infused in healthy human subjects.
Project description:BackgroundDyslipidaemias are common in patients with diabetes mellitus. A high prevalence of type 2 diabetes in hyperlipidaemic patients also exists. The aim of this study was to find a treatment that lowers both blood glucose and lipid levels simultaneously.MethodsThe hypolipidaemic effect of (R)-(-)-carvone was investigated in a tyloxapol-induced hyperlipidaemia mice model. Furthermore, its effect on insulin secretion and proliferation of 1.1E7 human pancreatic β-cells was studied. In addition, using molecular docking, the binding affinity of (R)-(-)-carvone against 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase was estimated.Results(R)-(-)-carvone (100 mg/kg) decreased plasma triglyceride, total cholesterol, low-density lipoprotein cholesterol (LDL-C) levels and atherogenic index by 90.6%, 49.3%, 56.6% and 70.3%, respectively, but it had no effect on high-density lipoprotein cholesterol (HDL-C). Furthermore, it increased hepatic triglyceride level and catalase activity by 79.6% and 59.6%, respectively. In-vitro, 500 μM (R)-(-)-carvone increased insulin secretion by 454.4% and proliferation of 1.1E7 cells with no cytotoxic effects up to a concentration of 100 μM. Molecular docking simulation demonstrated a good binding affinity with -5.03 Kcal/mol of (R)-(-)-carvone to HMG-CoA reductase.ConclusionThe hypolipidaemic effect of (R)-(-)-carvone is comparable to that of fenofibrate. (R)-(-)-carvone has the advantage over fenofibrate of not producing hypoglycaemia in animals. Furthermore, (R)-(-)-carvone increased proliferation and insulin secretion of human pancreatic β-cells.
Project description:Ethanolamine (Etn) is a naturally occurring aminoalcohol necessary for synthesis of the phospholipid phosphatidylethanolamine (PE), a major component of biological membranes. We recently reported that Etn treatment increases cellular PE levels, thereby inducing cytoprotective autophagy and protecting against aging across species.
Project description:Isoliquiritigenin (ISL), a natural product isolated from licorice root, exhibits anti-gastric cancer effects. However, applications of ISL are still limited in clinical practice due to its poor bioavailability. To discovery of more effective anti-gastric cancer agents based on ISL, aldol condensation reaction was applied to synthesize the ISL analogues. MTS assay was used to evaluate the inhibitory activities of ISL analogues against SGC-7901, BGC-823 and GES-1 cells in vitro. Cell cycle distribution, apoptosis and reactive oxygen species (ROS) generation were detected by flow cytometry. Western blot assay was used to analyze the expression levels of related proteins. The drug-likeness and pharmacokinetic properties were predicted with Osiris property explorer and PreADMET server. As a result, 18 new ISL analogues (ISL-1 to ISL-18) were synthesized. Among these analogues, ISL-17 showed the strongest inhibitory activities against SGC-7901 and BGC-823 cells, and could induce G2/M cell cycle arrest and apoptosis in these two cell lines. Treatment with ISL-17 resulted in increased ROS production and elevated autophagy levels in SGC-7901 cells. The PI3K/AKT/mTOR signaling pathway was down-regulated after treatment with ISL-17 in SGC-7901 cells. The results of drug-likeness and pharmacokinetic prediction indicated that all the ISL analogues complied with Lipinski's rule of five and Veber rule and had a favorable ADME character. Overall, our results attest that ISL-17 holds promise as a candidate agent against gastric cancer.
Project description:The structure of a novel indigoid component was characterized by X-ray crystallography. This compound exhibited excellent anti-tuberculosis activity against Mycobacterium tuberculosis H37Rv in whole cell culture showing a submicromolar minimum inhibitory concentration (MIC). A synthesis of this molecule was designed and carried out to produce sufficient material for further testing. The in vitro profile, structure, and first synthesis of this indigoid component is reported.
Project description:Coptis chinensis is an ancient Chinese herb treating diabetes in China for thousands of years. However, its underlying mechanism remains poorly understood. Here, we report the effects of its main active component, berberine (BBR), on stimulating insulin secretion. In mice with hyperglycemia induced by a high-fat diet, BBR significantly increases insulin secretion and reduced blood glucose levels. However, in mice with hyperglycemia induced by global or pancreatic islet β-cell-specific Kcnh6 knockout, BBR does not exert beneficial effects. BBR directly binds KCNH6 potassium channels, significantly accelerates channel closure, and subsequently reduces KCNH6 currents. Consequently, blocking KCNH6 currents prolongs high glucose-dependent cell membrane depolarization and increases insulin secretion. Finally, to assess the effect of BBR on insulin secretion in humans, a randomized, double-blind, placebo-controlled, two-period crossover, single-dose, phase 1 clinical trial (NCT03972215) including 15 healthy men receiving a 160-min hyperglycemic clamp experiment is performed. The pre-specified primary outcomes are assessment of the differences of serum insulin and C-peptide levels between BBR and placebo treatment groups during the hyperglycemic clamp study. BBR significantly promotes insulin secretion under hyperglycemic state comparing with placebo treatment, while does not affect basal insulin secretion in humans. All subjects tolerate BBR well, and we observe no side effects in the 14-day follow up period. In this study, we identify BBR as a glucose-dependent insulin secretagogue for treating diabetes without causing hypoglycemia that targets KCNH6 channels.
Project description:This study presents a phytochemical investigation of Lepionurus sylvestris leaf extracts and their anti-diabetic activities. Traditionally, L. sylvestris leaves were used as vegetables and food in local recipes, but the root extracts of the plant can also be used in body tonic and erectile dysfunction treatments. Following a preliminary anti-diabetic activity screening test, the 80% ethanolic leaf extract exhibited potent anti-alpha glucosidase activity. So, the leaves' active components were selected for further investigation. Firstly, the plant was extracted via maceration using lower to higher polarity solvents such as hexane, ethyl acetate, ethanol, and water, respectively, to obtain the four crude extracts. Then, the phytochemicals contained in this plant were investigated via classical column chromatography and spectroscopy techniques. Anti-diabetic activity was evaluated via anti-alpha glucosidase and insulin secretagogue assays. The results showed that five compounds were isolated from the fractionated ethanolic leaf extract: interruptin A; interruptin C; ergosterol; diglycerol; and 15-16-epoxy-neo-cleoda-3,7(20),13(16),14-tetraene-12,17:18,19-diolide, a new diterpene derivative which is herein referred to as lepionurodiolide. Interruptin A and the new diterpene derivative exhibited the greatest effect on anti-alpha glucosidase activity, showing IC50 values of 293.05 and 203.71 μg/mL, respectively. Then, molecular docking was used to study the sites of action of these compounds. The results showed that interruptin A and the new compound interacted through H-bonds with the GLN279 residue, with a binding energy of -9.8 kcal/mol, whereas interruptin A and C interacted with HIS280 and ARG315 a with binding energy of -10.2 kcal/mol. Moreover, the extracts were investigated for their toxicity toward human cancer cells, and a zebrafish embryonic toxicity model was used to determine herbal drug safety. The results indicated that ethyl acetate and hexane extracts showed cytotoxicity to both Hela cells and human breast adenocarcinomas (MCF-7), which was related to the results derived from using the zebrafish embryonic toxicity model. The hexane and ethyl acetate presented LC50 values of 33.25 and 36.55 μg/mL, respectively, whereas the ethanol and water extracts did not show embryonic toxicity. This study is the first of its kind to report on the chemical constituents and anti-diabetic activity of L. sylvestris, the leaf extract of which has been traditionally used in southern Thailand as a herbal medicine and food ingredient.
Project description:ABSTRACT The PI3K/mTOR pathway is one of the most frequently aberrantly activated pathways in human malignancies, such as renal cell carcinoma (RCC), and contributes to resistance to antitumor therapies. Thus, PI3K/mTOR is an attractive target for the development of antitumor agents. In this study, we evaluated the preclinical effects of a novel inhibitor SN202. We examined Akt/mTOR activities in renal cancer cells after SN202 treatment. The preclinical effects of SN202 on tumor growth were evaluated in renal cancer cells in vitro and in murine xenografts in vivo. SN202 inhibits PI3Kα, PI3Kγ, and mTOR, the corresponding IC50 values were 3.2, 3.3, and 1.2 nM, respectively. In A498, 786-0, and ACHN renal cancer cell lines, SN202 inhibits cell proliferation in a dose-dependent manner and significantly inhibits 786-0 cell growth. Western blot analysis revealed that SN202 decreases the phosphorylation of PI3K downstream signaling molecules, Akt and S6K, in 786-0 renal cancer cells. Furthermore, oral administration of SN202 results in significant inhibition in human renal carcinoma xenografts in nude mice and favourable pharmacokinetic properties in rats. These results suggest that SN202 might be a promising therapeutic agent against RCC as a dual PI3K/mTOR inhibitor.