Diabetes area participation analysis: a review of companies and targets described in the 2008 – 2010 patent literature

Polysaccharides (pectin, mucilage, and fructan inulin) and their fermented products: A critical analysis of their biochemical, gut interactions, and biological functions as antidiabetic agents

Diabetes mellitus is a globally metabolic endocrine syndrome marked by a deficiency of insulin secretion (type-1 DM) or glucose intolerance arising from insulin response impairment (type-2 DM) leading to abnormal glucose metabolism. With an increasing interest in natural dietary components for diabetes management, the identification of novel agents witnessed major discoveries. Plant-derived mucilage, pectin, and inulin are important non-starch polysaccharides that exhibit effective antidiabetic properties often termed soluble dietary fiber (SDF). SDF affects sugar metabolism through multiple mechanisms affecting glucose absorption and diffusion, modulation of carbohydrate metabolizing enzymes (α-amylase and α-glucosidase), ameliorating β-pancreatic cell dysfunction, and improving insulin release or sensitivity. Certain SDFs inhibit dipeptidyl peptidase-4 and influence the expression levels of genes related to glucose metabolism. This review is designed to discuss holistically and critically the antidiabetic effects of major SDF and their underlying mechanisms of action. This review should aid drug discovery approaches in developing novel natural antidiabetic drugs from SDF.

Immobilized enzyme for screening and identification of anti-diabetic components from natural products by ligand fishing

Diabetes is a chronic metabolic disease caused by insufficient insulin secretion and insulin resistance. Natural product is one of the most important resources for anti-diabetic drug. However, due to the extremely complex composition, this research is facing great challenges. After the advent of ligand fishing technology based on enzyme immobilization, the efficiency of screening anti-diabetic components has been greatly improved. In order to provide critical knowledge for future research in this field, the application progress of immobilized enzyme in screening anti-diabetic components from complex natural extracts in recent years was reviewed comprehensively, including novel preparation technologies and strategies of immobilized enzyme and its outstanding application prospect in many aspects. The basic principles and preparation steps of immobilized enzyme were briefly described, including entrapment, physical adsorption, covalent binding, affinity immobilization, multienzyme system and carrier-free immobilization. New formatted immobilized enzymes with different carriers, hollow fibers, magnetic materials, microreactors, metal organic frameworks, etc., were widely used to screen anti-diabetic compositions from various natural products, such as Ginkgo biloba, Morus alba, lotus leaves, Pueraria lobata, Prunella vulgaris, and Magnolia cortex. Furthermore, the challenges and future prospects in this field were put forward in this review.

A review of patent literature on the regulation of glucose metabolism by six phytocompounds in the management of diabetes mellitus and its complications

Diabetes mellitus is a chronic disease, typified by hyperglycemia resulting from failures in complex multifactorial metabolic functions, that requires life-long medication. Prolonged uncontrolled hyperglycemia leads to micro- and macro-vascular complications. Although antidiabetic drugs are prescribed as the first-line treatment, many of them lose efficacy over time or have severe side effects. There is a lack of in-depth study on the patents filed concerning the use of natural compounds to manage diabetes. Thus, this patent analysis provides a comprehensive report on the antidiabetic therapeutic activity of 6 phytocompounds when taken alone or in combinations. Four patent databases were searched, and 17,649 patents filed between 2001 and 2021 were retrieved. Of these, 139 patents for antidiabetic therapeutic aids that included berberine, curcumin, gingerol, gymnemic acid, gymnemagenin and mangiferin were analyzed. The results showed that these compounds alone or in combinations, targeting acetyl-coenzyme A carboxylase 2, serine/threonine protein kinase, α-amylase, α-glucosidase, lipooxygenase, phosphorylase, peroxisome proliferator-activated receptor-γ (PPARγ), protein tyrosine phosphatase 1B, PPARγ co-activator-1α, phosphoinositide 3-kinase and protein phosphatase 1 regulatory subunit 3C, could regulate glucose metabolism which are validated by pharmacological rationale. Synergism, or combination therapy, including different phytocompounds and plant extracts, has been studied extensively and found effective, whereas the efficacy of commercial drugs in combination with phytocompounds has not been studied in detail. Curcumin, gymnemic acid and mangiferin were found to be effective against diabetes-related complications.

Macrophages, Chronic Inflammation, and Insulin Resistance

The prevalence of obesity has reached alarming levels, which is considered a major risk factor for several metabolic diseases, including type 2 diabetes (T2D), non-alcoholic fatty liver, atherosclerosis, and ischemic cardiovascular disease. Obesity-induced chronic, low-grade inflammation may lead to insulin resistance, and it is well-recognized that macrophages play a major role in such inflammation. In the current review, the molecular mechanisms underlying macrophages, low-grade tissue inflammation, insulin resistance, and T2D are described. Also, the role of macrophages in obesity-induced insulin resistance is presented, and therapeutic drugs and recent advances targeting macrophages for the treatment of T2D are introduced.

Molecular insights into human taste perception and umami tastants: A review

Understanding taste is key for optimizing the palatability of seaweeds and other non‐animal‐based foods rich in protein. The lingual papillae in the mouth hold taste buds with taste receptors for the five gustatory taste qualities. Each taste bud contains three distinct cell types, of which Type II cells carry various G protein‐coupled receptors that can detect sweet, bitter, or umami tastants, while type III cells detect sour, and likely salty stimuli. Upon ligand binding, receptor‐linked intracellular heterotrimeric G proteins initiate a cascade of downstream events which activate the afferent nerve fibers for taste perception in the brain. The taste of amino acids depends on the hydrophobicity, size, charge, isoelectric point, chirality of the alpha carbon, and the functional groups on their side chains. The principal umami ingredient monosodium l‐glutamate, broadly known as MSG, loses umami taste upon acetylation, esterification, or methylation, but is able to form flat configurations that bind well to the umami taste receptor. Ribonucleotides such as guanosine monophosphate and inosine monophosphate strongly enhance umami taste when l‐glutamate is present. Ribonucleotides bind to the outer section of the venus flytrap domain of the receptor dimer and stabilize the closed conformation. Concentrations of glutamate, aspartate, arginate, and other compounds in food products may enhance saltiness and overall flavor. Umami ingredients may help to reduce the consumption of salts and fats in the general population and increase food consumption in the elderly.

Integration of network and experimental pharmacology to decipher the antidiabetic action of Duranta repens L

OBJECTIVE

Duranta repens is reported to contain a wide array of secondary metabolites, including α-amylase and α-glucosidase inhibitors, and - has potent antioxidant activity. The present study evaluated the network pharmacology of D. repens (whole plant) with targets related to diabetes mellitus and assessed its outcome by evaluating the effects of the hydroalcoholic extract of D. repens in streptozotocin-nicotinamide-induced diabetes mellitus in rats.

METHODS

Phytoconstituents of D. repens were retrieved from an open-source database and published literature, and their targets were predicted for diabetes mellitus using BindingDB and the therapeutic target database. Protein-protein interaction was predicted using STRING, and pathways involved in diabetes mellitus were identified using the Kyoto Encyclopedia of Genes and Genomes pathway browser. Druglikeness, ADMET profile (absorption, distribution, metabolism, excretion and toxicity) and cytotoxicity of compounds modulating proteins involved in diabetes were predicted using MolSoft, admetSAR2.0 and CLC-Pred, respectively. The interaction network among phytoconstituents, proteins and pathways was constructed using Cytoscape, and the docking study was performed using AutoDock4.0. The hydroalcoholic extract of D. repens was evaluated using streptozotocin-nicotinamide-induced diabetes mellitus animal model for 28 d, followed by an oral glucose tolerance test. At the end of the study, biochemical parameters like glycogen content, hepatic enzymes, antioxidant biomarkers and lipid profiles were quantified. Further, the liver and pancreas were collected for a histopathology study.

RESULTS

Thirty-six different secondary metabolites from D. repens were identified to regulate thirty-one targets involved in diabetes mellitus, in which protein-tyrosine phosphatase 1B (PTP1B) was primarily targeted. Enrichment analysis of modulated proteins identified 12 different pathways in diabetic pathogenesis in which the phosphatidylinositol 3-kinase-protein kinase B (PI3K-Akt) signaling pathway was chiefly regulated. The docking study found that durantanin I possessed the highest binding affinity (-8.9 kcal/mol) with PTP1B. Similarly, ADMET profiling showed that the majority of bioactive constituents from D. repens had higher human intestinal absorptivity and minimal cytotoxicity to normal cell lines, than tumor cell lines. Further, an in vivo animal study reflected the efficacy of the hydroalcoholic extract of D. repens to lower the elevated blood glucose level by stimulating insulin secretion, maintaining pancreatic β cell mass, regulating glycolysis/gluconeogenesis and enhancing the glucose uptake in skeletal muscles.

CONCLUSION

The present study reflected the probable network interaction of bioactive constituents from D. repens, their targets and modulated pathways, which identified the prime regulation of the PI3K-Akt signaling pathway and PTP1B protein. Modulation of PTP1B protein and PI3K-Akt signaling pathway could contribute to enhancing glucose uptake, insulin production and glycolysis and decreasing gluconeogenesis in diabetes, which was evaluated via the experimental study.

Modified UCN2 Peptide Acts as an Insulin Sensitizer in Skeletal Muscle of Obese Mice

The neuropeptide urocortin 2 (UCN2) and its receptor corticotropin-releasing hormone receptor 2 (CRHR2) are highly expressed in skeletal muscle and play a role in regulating energy balance and glucose metabolism. We investigated a modified UCN2 peptide as a potential therapeutic agent for the treatment of obesity and insulin resistance, with a specific focus on skeletal muscle. High-fat-fed mice (C57BL/6J) were injected daily with a PEGylated UCN2 peptide (compound A) at 0.3 mg/kg subcutaneously for 14 days. Compound A reduced body weight, food intake, whole-body fat mass, and intramuscular triglycerides compared with vehicle-treated controls. Furthermore, whole-body glucose tolerance was improved by compound A treatment, with increased insulin-stimulated Akt phosphorylation at Ser⁴⁷³ and Thr³⁰⁸ in skeletal muscle, concomitant with increased glucose transport into extensor digitorum longus and gastrocnemius muscle. Mechanistically, this is linked to a direct effect on skeletal muscle because ex vivo exposure of soleus muscle from chow-fed lean mice to compound A increased glucose transport and insulin signaling. Moreover, exposure of GLUT4-Myc-labeled L6 myoblasts to compound A increased GLUT4 trafficking. Our results demonstrate that modified UCN2 peptides may be efficacious in the treatment of type 2 diabetes by acting as an insulin sensitizer in skeletal muscle.

The Glucose Lowering Effect of Zornia gibbosa Span Extracts in Diabetic Rats

OBJECTIVES

Diabetes mellitus is a chronic, lifelong condition that affects our body physiology. Untreated diabetes mellitus causes diseases such as diabetic retinopathy, diabetic nephropathy and diabetic neuropathy, auto immune diseases, polyuria, polydipsia, loss of weight, and cardiovascular diseases. The use of medications for the treatment of diabetes mellitus causes adverse effects with long-term use, and sometimes leads to death. Today, researchers are working on the discovery of new anti-diabetes drugs from plants with low or no adverse effects. From this point of view, the present work was conducted to evaluate the anti-diabetic activity of Zornia gibbosa Span.

MATERIALS AND METHODS

This acute toxicity study was conducted for ethyl acetate and ethanol (70%v/v) extracts of Z. gibbosa as per OECD guidelines. The anti-diabetic activity of selected plant extracts were tested using alloxan-induced diabetes in a rat model.

RESULTS

No mortality was observed in the administered doses of Zornia gibbosa Span extracts. The tested extracts significantly (p≤0.01) restored the physiologic changes that occurred due to the alloxan-induced diabetes mellitus. The hydroalcoholic extracts at 500 mg/kg body weight concentration showed more activity compared with other extracts at different concentrations along with standard drug (glibenclamide). Zornia gibbosa significantly decreased glucose concentrations and restored the altered enzymes levels caused by damage to different organs by diabetes.

CONCLUSION

The results of the present study indicate that Z. gibbosa has a significant anti-diabetic activity. Therefore, it may be capable of use as an alternate medicine along with allopathic medicine in the treatment of diabetes as well as its health problems.

Mangiferin: An effective therapeutic agent against several disorders (Review)

Mangiferin (1,3,6,7‑tetrahydroxyxanthone‑C2‑β‑D‑glucoside) is a bioactive ingredient predominantly isolated from the mango tree, with potent antioxidant activity and multifactorial pharmacological effects, including antidiabetic, antitumor, lipometabolism regulating, cardioprotective, anti‑hyperuricemic, neuroprotective, antioxidant, anti‑inflammatory, antipyretic, analgesic, antibacterial, antiviral and immunomodulatory effects. Therefore, it possesses several health‑endorsing properties and is a promising candidate for further research and development. However, low solubility, mucosal permeability and bioavailability restrict the development of mangiferin as a clinical therapeutic, and chemical and physical modification is required to expand its application. This review comprehensively analyzed and collectively summarized the primary pharmacological actions of mangiferin that have been demonstrated in the literature, to support the potential future development of mangiferin as a novel therapeutic drug.

Involvement of estrogen receptors in silibinin protection of pancreatic β-cells from TNFα- or IL-1β-induced cytotoxicity

Silibinin is a polyphenolic flavonoid that exhibits anticarcinogenic, anti-inflammatory and cytoprotective effects. The effect of silibinin on pancreatic islet β-cell is yet largely unknown in spite of well documented-hepatoprotective effects. Protecting the functional insulin-producing β-cells in the pancreas is a major therapeutic challenge in the patients with type 1 (T1DM) or type 2 diabetes mellitus (T2DM). This study reports the effect of silibinin on the rat pancreatic β-cell line, INS-1, damaged with pro-inflammatory cytokine, TNFα or IL-1β. Exposure to TNFα or IL-1β for 48 h caused INS-1 cells to reduce the production of insulin as well as cell viability. These actions of TNFα or IL-1β are associated with suppression of the expression of estrogen receptors (ERs). Further study revealed that silibinin protected the suppression in the expression of both ERα and ERβ that were involved in insulin synthesis and release, respectively. Furthermore, evidence is obtained that silibinin may impede the loss of critical INS-1 cells by promoting autophagy and preventing apoptosis. Direct cytoprotective effects of silibinin on INS-1 cells suggest that silibinin may be therapeutically beneficial for diabetes.

An Integrated Computational Approach for Plant-Based Protein Tyrosine Phosphatase Non-Receptor Type 1 Inhibitors

BACKGROUND

Protein tyrosine phosphatase non-receptor type 1 is a therapeutic target for the type 2 diabetes mellitus. According to the International Diabetes Federation 2015 report, one out of 11 adults suffers from diabetes mellitus globally.

OBJECTIVE

Current anti-diabetic drugs can cause life-threatening side-effects. The present study proposes a pipeline for the development of effective and plant-derived anti-diabetic drugs that may be safer and better tolerated.

METHODS

Plant-derived protein tyrosine phosphatase non-receptor type 1 inhibitors possessing antidiabetic activity less than 10µM were used as a training set. A common feature pharmacophore model was generated. Pharmacophore-based screening of plant-derived compounds of the ZINC database was conducted using ZINCpharmer. Screened hits were assessed to evaluate their drug-likeness, pharmacokinetics, detailed binding behavior, and aggregator possibility based on their physiochemical properties and chemical similarity with reported aggregators.

RESULTS

Through virtual screening and in silico pharmacology protocol isosilybin (ZINC30731533) was identified as a lead compound with optimal properties. This compound can be recommended for laboratory tests and further analyses to confirm its activity as protein tyrosine phosphatase nonreceptor type 1 inhibitor.

CONCLUSION

The present study has identified plant-derived anti-diabetic virtual lead compound with the potential to inhibit protein tyrosine phosphatase non-receptor type 1, which may be helpful to enhance insulin production. This computer-aided study could facilitate the development of novel pharmacological inhibitors for diabetes treatment.

Computational prediction of formulation strategies for beyond-rule-of-5 compounds

The physicochemical properties of some contemporary drug candidates are moving towards higher molecular weight, and coincidentally also higher lipophilicity in the quest for biological selectivity and specificity. These physicochemical properties move the compounds towards beyond rule-of-5 (B-r-o-5) chemical space and often result in lower water solubility. For such B-r-o-5 compounds non-traditional delivery strategies (i.e. those other than conventional tablet and capsule formulations) typically are required to achieve adequate exposure after oral administration. In this review, we present the current status of computational tools for prediction of intestinal drug absorption, models for prediction of the most suitable formulation strategies for B-r-o-5 compounds and models to obtain an enhanced understanding of the interplay between drug, formulation and physiological environment. In silico models are able to identify the likely molecular basis for low solubility in physiologically relevant fluids such as gastric and intestinal fluids. With this baseline information, a formulation scientist can, at an early stage, evaluate different orally administered, enabling formulation strategies. Recent computational models have emerged that predict glass-forming ability and crystallisation tendency and therefore the potential utility of amorphous solid dispersion formulations. Further, computational models of loading capacity in lipids, and therefore the potential for formulation as a lipid-based formulation, are now available. Whilst such tools are useful for rapid identification of suitable formulation strategies, they do not reveal drug localisation and molecular interaction patterns between drug and excipients. For the latter, Molecular Dynamics simulations provide an insight into the interplay between drug, formulation and intestinal fluid. These different computational approaches are reviewed. Additionally, we analyse the molecular requirements of different targets, since these can provide an early signal that enabling formulation strategies will be required. Based on the analysis we conclude that computational biopharmaceutical profiling can be used to identify where non-conventional gateways, such as prediction of 'formulate-ability' during lead optimisation and early development stages, are important and may ultimately increase the number of orally tractable contemporary targets.

Anti-obesity and anti-diabetic effects of flavonoid derivative (Fla-CN) via microRNA in high fat diet induced obesity mice

3-O-[(E)-4-(4-cyanophenyl)-2-oxobut-3-en-1-yl]kaempferol (Fla-CN), a semi-synthesized flavonoid derivative of tiliroside, reduces whole-body adiposity, ameliorates metabolic lipid disorder, improves insulin sensitivity and benefits other disorders characterized by insulin resistance in high fat diet induced obesity mice. The improvement of insulin sensitivity and the reduction of weight gain are correlated with the changes of leptin and adiponectin levels. As a result, Fla-CN treatment could increase the expressions of pAMPK and miR-27 in the liver and adipose tissues. Meanwhile, we discovered that the expressions of various adipogenesis genes were downregulated, which were target genes of miR-27. This is the first report for the action of miR-27 by flavonoid derivative in rodents. The action of Fla-CN might be through multiple approaches including AMPK activation and enhancement in miR-27 expression.

Serum phospholipid monounsaturated fatty acid composition and Δ-9-desaturase activity are associated with early alteration of fasting glycemic status

Because alterations in blood fatty acid (FA) composition by dietary lipids are associated with insulin resistance and related metabolic disorders, we hypothesized that serum phospholipid FA composition would reflect the early alteration of fasting glycemic status, even in people without metabolic syndrome (MetS). To examine this hypothesis, serum phospholipid FA, desaturase activities, fasting glycemic status, and cardiometabolic parameters were measured in study participants (n = 1022; 30-69 years; male, n = 527; female, n = 495; nondiabetics without disease) who were stratified into normal fasting glucose (NFG) and impaired fasting glucose (IFG) groups. Total monounsaturated FA (MUFA), oleic acid (OA; 18:1n-9), dihomo-γ-linolenic acid (DGLA; 20:3n-6), Δ-9-desaturase activity (D9D; 18:1n-9/18:0), and DGLA/linoleic acid (20:3n-6/18:2n-6) in serum phospholipids were significantly higher in IFG subjects than NFG controls. Study subjects were subdivided into 4 groups, based on fasting glucose levels and MetS status. Palmitoleic acid (16:1n-7) was highest in IFG-MetS and lowest in NFG-non-MetS subjects. Oleic acid and D9D were higher in IFG-MetS than in the other 3 groups. Dihomo-γ-linolenic acid and DGLA/linoleic acid were higher in MetS than in non-MetS, regardless of fasting glucose levels. The high-sensitivity C-reactive proteins (hs-CRPs) and 8-epi-prostaglandin-F2α were higher in IFG than in NFG, regardless of MetS status. Oxidized low-density lipoproteins were higher in IFG-MetS than in the other 3 groups. Total MUFAs, OA, and D9D were positively correlated with homeostasis model assessment of insulin resistance, fasting glucose, triglyceride, hs-CRP, and 8-epi-prostaglandin-F2α. Palmitoleic acid was positively correlated with triglyceride and hs-CRP. Lastly, total MUFA, OA, palmitoleic acid, and D9D were associated with early alteration of fasting glycemic status, therefore suggesting that these may be useful markers for predicting the risk of type 2 diabetes and cardiometabolic diseases.

Building structure-activity insights through patent mining

One gap in current patent-mining practice is the lack of tools to build SAR knowledge. Here, we report a novel technique that enabled us to derive useful SAR information from the exemplified structures of a series of patents. In our approach, exemplified chemical structures were extracted from patent documents. They were grouped into structural series based on similarity and binding mode, after which the R-group table was generated. By analyzing R-group usages over time, we were able to build insights into SAR of a structural series, even though the biological activities were not available.

MicroRNAs as pharmacological targets in diabetes

Diabetes is characterized by high levels of blood glucose due to either the loss of insulin-producing beta-cells in the pancreas, leading to a deficiency of insulin in type 1 diabetes, or due to increased insulin resistance, leading to reduced insulin sensitivity and productivity in type 2 diabetes. There is an increasing need for new options to treat diabetes, especially type 2 diabetes at its early stages due to an ineffective control of its development in patients. Recently, a novel class of small noncoding RNAs, termed microRNAs (miRNAs), is found to play a key role as important transcriptional and posttranscriptional inhibitors of gene expression in fine-tuning the target messenger RNAs (mRNAs). miRNAs are implicated in the pathogenesis of diabetes and have become an intriguing target for therapeutic intervention. This review focuses on the dysregulated miRNAs discovered in various diabetic models and addresses the potential for miRNAs to be therapeutic targets in the treatment of diabetes.

Find novel dual-agonist drugs for treating type 2 diabetes by means of cheminformatics

The high prevalence of type 2 diabetes mellitus in the world as well as the increasing reports about the adverse side effects of the existing diabetes treatment drugs have made developing new and effective drugs against the disease a very high priority. In this study, we report ten novel compounds found by targeting peroxisome proliferator-activated receptors (PPARs) using virtual screening and core hopping approaches. PPARs have drawn increasing attention for developing novel drugs to treat diabetes due to their unique functions in regulating glucose, lipid, and cholesterol metabolism. The reported compounds are featured with dual functions, and hence belong to the category of dual agonists. Compared with the single PPAR agonists, the dual PPAR agonists, formed by combining the lipid benefit of PPARα agonists (such as fibrates) and the glycemic advantages of the PPARγ agonists (such as thiazolidinediones), are much more powerful in treating diabetes because they can enhance metabolic effects while minimizing the side effects. This was observed in the studies on molecular dynamics simulations, as well as on absorption, distribution, metabolism, and excretion, that these novel dual agonists not only possessed the same function as ragaglitazar (an investigational drug developed by Novo Nordisk for treating type 2 diabetes) did in activating PPARα and PPARγ, but they also had more favorable conformation for binding to the two receptors. Moreover, the residues involved in forming the binding pockets of PPARα and PPARγ among the top ten compounds are explicitly presented, and this will be very useful for the in-depth conduction of mutagenesis experiments. It is anticipated that the ten compounds may become potential drug candidates, or at the very least, the findings reported here may stimulate new strategies or provide useful insights for designing new and more powerful dual-agonist drugs for treating type 2 diabetes.

Model-based drug development: a rational approach to efficiently accelerate drug development

The pharmaceutical industry continues to face significant challenges. Very few compounds that enter development reach the marketplace, and the investment required for each success can surpass $1.8 billion. Despite attempts to improve efficiency and increase productivity, total investment continues to rise whereas the output of new medicines declines. With costs increasing exponentially through each development phase, it is failure in phase II and phase III that is most wasteful. In today's development paradigm, late-stage failure is principally a result of insufficient efficacy. This is manifested as either a failure to differentiate sufficiently from placebo (shown for both novel and precedented mechanisms) or a failure to demonstrate sufficient differentiation from existing compounds. Set in this context, this article will discuss the role model-based drug development (MBDD) approaches can and do play in accelerating and optimizing compound development strategies through a series of illustrative examples.

Latest research and development trends in non-insulin anti-diabetics

Type 2 diabetes mellitus, also called non-insulin dependent diabetes mellitus, is a chronic endocrine disease characterized by insulin resistance in tissues such as fat, liver and skeletal muscle, and impaired insulin secretion in pancreatic β cells. The prevalence and incidence of type 2 diabetes exploded over last decades along with increased population obesity owing to western lifestyle factors such as lack of exercise and high calorie diets. As diabetes progresses without appropriate treatment, many micro- and macro-vascular complications occur, leading to increased risk of mortality. Although lifestyle modifications including a healthier diet and more frequent exercise are suggested as initial therapy for type 2 diabetes, pharmacotherapy is required in many cases. Currently, several anti-diabetic drugs with different mechanisms of action are available, but increased effectiveness and tolerability are a still unmet need for diabetes pharmacotherapy. Thus, the development of new anti-diabetic drugs is an active research area in both academia and the pharmaceutical industry. This review focuses on the targets in the latest developments of non-insulin anti-diabetics that attract the most interest in this disease area.

Sterculic oil, a natural inhibitor of SCD1, improves the metabolic state of obese OLETF rats

OBJECTIVE

Abnormal lipid metabolism and excess accumulation of lipid in non-adipose tissues are defining characteristics of obesity and its comorbidities. Expression and/or activity of stearoyl-CoA desaturase-1 (SCD1), a major regulator of lipid metabolism, is increased with obesity and the reduction/ablation of this enzyme is associated with an improved metabolic profile. Sterculic oil (SO), obtained from the seeds of the Sterculia feotida tree, contains a high concentration of cyclopropenoic fatty acids which are known inhibitors of SCD1. The purpose of this study was to determine the effects of SO supplementation on the development of obesity and insulin resistance in hyperphagic, obese Otsuka Long-Evans Tokushima Fatty (OLETF) rats.

DESIGN & METHODS

Rats received either an AIN-93G diet (control) or an AIN-93G diet containing 0.5% SO for 10 weeks.

RESULTS

SO did not alter body weight or body composition. Importantly, the desaturase indices, a proxy for the activity of SCD1, were reduced in the liver and adipose tissue of SO supplemented animals. This reduction in SCD1 activity was associated with a reduction in fasting blood glucose concentrations and improved glucose tolerance. In addition, SO reduced intra-abdominal fat mass and adipocyte size and resulted in a ∼3-fold increase in GLUT1 gene expression in intra-abdominal fat. Liver triglyceride content and lipogenic gene expression were reduced by SO. Consistent with an improved metabolic phenotype, SO also improved plasma cholesterol, LDL-cholesterol, and triglyceride concentrations.

CONCLUSION

Overall, our data demonstrate an improved metabolic phenotype with SO supplementation and suggest further studies are required to better understand the therapeutic potential of SO.

The Hypothalamic-Pituitary-Adrenal Axis, Obesity, and Chronic Stress Exposure: Sleep and the HPA Axis in Obesity

Obesity, exposure to stress and inadequate sleep are prevalent phenomena in modern society. In this review we focus on their relationships and critically evaluate causality. In obese individuals, one of the main stress systems, the hypothalamic-pituitary-adrenal axis, is altered, and concentrations of cortisol are elevated in adipose tissue due to elevated local activity of 11β-hydroxysteroid dehydrogenase (HSD) type 1. Short sleep and decreased sleep quality are also associated with obesity. In addition, experimental sleep curtailment induces HPA-axis alterations which, in turn, may negatively affect sleep. These findings implicate that obesity, stress and sleep loss are all related in a vicious circle. Finally, we discuss new strategies to combat obesity through modulating cortisol levels in adipose tissue by 11β-HSD(1) inhibitors or by improving sleep duration.

Sterculic Oil, a Natural SCD1 Inhibitor, Improves Glucose Tolerance in Obese ob/ob Mice

Obesity and its metabolic complications are associated with increased expression/activity of stearoyl-CoA desaturase-1 (SCD1), a major regulator of lipid metabolism. Reduction or ablation of this enzyme is associated with an improved metabolic profile and has gained attention as a target for pharmaceutical development. Sterculic oil (SO) is a known inhibitor of SCD1 and may provide a natural approach for treating obesity and/or insulin resistance. The purpose of this study was to evaluate the effects of SO consumption in leptin-deficient ob/ob mice, a model of obesity and insulin resistance. Five-week-old male mice received either an AIN-93G (control) or an AIN-93G diet containing 0.5% SO. After 9 weeks, SO supplementation did not alter food intake or body weight; however, the desaturase indices, a proxy of SCD1 activity, were reduced in liver and adipose tissue of SO-supplemented animals. This reduction was associated with improved glucose and insulin tolerance and attenuated hepatic inflammation in obese ob/ob mice, while no appreciable changes were observed in lean control mice receiving SO. Future studies are needed to better understand the mechanism(s) by which SO is functioning to improve glucose metabolism and to further explore the nutraceutical potential and health implications of SO supplementation.

Action of molecular switches in GPCRs--theoretical and experimental studies

G protein coupled receptors (GPCRs), also called 7TM receptors, form a huge superfamily of membrane proteins that, upon activation by extracellular agonists, pass the signal to the cell interior. Ligands can bind either to extracellular N-terminus and loops (e.g. glutamate receptors) or to the binding site within transmembrane helices (Rhodopsin-like family). They are all activated by agonists although a spontaneous auto-activation of an empty receptor can also be observed. Biochemical and crystallographic methods together with molecular dynamics simulations and other theoretical techniques provided models of the receptor activation based on the action of so-called "molecular switches" buried in the receptor structure. They are changed by agonists but also by inverse agonists evoking an ensemble of activation states leading toward different activation pathways. Switches discovered so far include the ionic lock switch, the 3-7 lock switch, the tyrosine toggle switch linked with the nPxxy motif in TM7, and the transmission switch. The latter one was proposed instead of the tryptophan rotamer toggle switch because no change of the rotamer was observed in structures of activated receptors. The global toggle switch suggested earlier consisting of a vertical rigid motion of TM6, seems also to be implausible based on the recent crystal structures of GPCRs with agonists. Theoretical and experimental methods (crystallography, NMR, specific spectroscopic methods like FRET/BRET but also single-molecule-force-spectroscopy) are currently used to study the effect of ligands on the receptor structure, location of stable structural segments/domains of GPCRs, and to answer the still open question on how ligands are binding: either via ensemble of conformational receptor states or rather via induced fit mechanisms. On the other hand the structural investigations of homoand heterodimers and higher oligomers revealed the mechanism of allosteric signal transmission and receptor activation that could lead to design highly effective and selective allosteric or ago-allosteric drugs.

The case for intraocular delivery of PPAR agonists in the treatment of diabetic retinopathy

Background

Systemic therapeutics targeting the peroxisome proliferator-activated receptors have been found to be beneficial in the treatment of diabetic retinopathy. In this paper, we provide a rationale for the use of these therapeutics as intraocular agents. In addition, we introduce the peroxisome proliferator-activated receptors and describe their functions in response to the drugs.

Discussion

Based on the evidence of large-scale clinical studies investigating the systemic administration of fenofibrate, this ligand for peroxisome proliferator-activated receptor-α is potentially a good candidate for intraocular delivery. Here, we describe the mechanisms by which it might be acting to improve diabetic retinopathy, its relative safety and we speculate on how it could be developed for intraocular delivery.

Summary

In this paper, we provide a rationale for the further investigation of peroxisome proliferator-activated receptor-α agonists as intraocular agents for the treatment of diabetic retinopathy.

Transgenic mouse models resistant to diet-induced metabolic disease: is energy balance the key?

The prevalence and economic burden of obesity and type 2 diabetes is a driving force for the discovery of molecular targets to improve insulin sensitivity and glycemic control. Here, we review several transgenic mouse models that identify promising targets, ranging from proteins involved in the insulin signaling pathway, alterations of genes affecting energy metabolism, and transcriptional metabolic regulators. Despite the diverse endpoints in each model, a common thread that emerges is the necessity for maintenance of energy balance, suggesting pharmacotherapy must target the development of drugs that decrease energy intake, accelerate energy expenditure in a well controlled manner, or augment natural compensatory responses to positive energy balance.

Design novel dual agonists for treating type-2 diabetes by targeting peroxisome proliferator-activated receptors with core hopping approach

Owing to their unique functions in regulating glucose, lipid and cholesterol metabolism, PPARs (peroxisome proliferator-activated receptors) have drawn special attention for developing drugs to treat type-2 diabetes. By combining the lipid benefit of PPAR-alpha agonists (such as fibrates) with the glycemic advantages of the PPAR-gamma agonists (such as thiazolidinediones), the dual PPAR agonists approach can both improve the metabolic effects and minimize the side effects caused by either agent alone, and hence has become a promising strategy for designing effective drugs against type-2 diabetes. In this study, by means of the powerful “core hopping” and “glide docking” techniques, a novel class of PPAR dual agonists was discovered based on the compound GW409544, a well-known dual agonist for both PPAR-alpha and PPAR-gamma modified from the farglitazar structure. It was observed by molecular dynamics simulations that these novel agonists not only possessed the same function as GW409544 did in activating PPAR-alpha and PPAR-gamma, but also had more favorable conformation for binding to the two receptors. It was further validated by the outcomes of their ADME (absorption, distribution, metabolism, and excretion) predictions that the new agonists hold high potential to become drug candidates. Or at the very least, the findings reported here may stimulate new strategy or provide useful insights for discovering more effective dual agonists for treating type-2 diabetes. Since the “core hopping” technique allows for rapidly screening novel cores to help overcome unwanted properties by generating new lead compounds with improved core properties, it has not escaped our notice that the current strategy along with the corresponding computational procedures can also be utilized to find novel and more effective drugs for treating other illnesses.

Pharmacodynamic model of sodium-glucose transporter 2 (SGLT2) inhibition: implications for quantitative translational pharmacology

Sodium-glucose co-transporter-2 (SGLT2) inhibitors are an emerging class of agents for use in the treatment of type 2 diabetes mellitus (T2DM). Inhibition of SGLT2 leads to improved glycemic control through increased urinary glucose excretion (UGE). In this study, a biologically based pharmacokinetic/pharmacodynamic (PK/PD) model of SGLT2 inhibitor-mediated UGE was developed. The derived model was used to characterize the acute PK/PD relationship of the SGLT2 inhibitor, dapagliflozin, in rats. The quantitative translational pharmacology of dapagliflozin was examined through both prospective simulation and direct modeling of mean literature data obtained for dapagliflozin in healthy subjects. Prospective simulations provided time courses of UGE that were of consistent shape to clinical observations, but were modestly biased toward under prediction. Direct modeling provided an improved characterization of the data and precise parameter estimates which were reasonably consistent with those predicted from preclinical data. Overall, these results indicate that the acute clinical pharmacology of SGLT2 inhibitors in healthy subjects can be reasonably well predicted from preclinical data through rational accounting of species differences in pharmacokinetics, physiology, and SGLT2 pharmacology. Because these data can be generated at the earliest stages of drug discovery, the proposed model is useful in the design and development of novel SGLT2 inhibitors. In addition, this model is expected to serve as a useful foundation for future efforts to understand and predict the effects of SGLT2 inhibition under chronic administration and in other patient populations.