Identification of potential AMPK activator by pharmacophore modeling, molecular docking and QSAR study.

AMP-activated protein kinase (AMPK) plays a major role in maintaining cellular energy homeostasis by sensing and responding to AMP/ADP concentrations relative to ATP. AMPK has attracted widespread attention as a potential therapeutic target for metabolic diseases such as cancer and cardiovascular diseases. The structure-based 3D pharmacophore model was developed based on the training set. The best pharmacophore model Hypo5 was proposed and validated using a decoy set, an external test set. Hypo5, with the correlation coefficient value of 0.936, cost difference value of 112.08 and low RMS value of 1.63, includes a ionizable positive, a hydrogen bond donor, a hydrogen bond acceptor and two hydrophobic features, which showed a high goodness of fit and enrichment factor. Thus it was used as a 3D query to find potential activator from the SPECS Database. Then the ADMET descriptors were used to filter all of 158 screening molecules. The 41 filtering compounds were subsequently subjected to molecular docking and Quantitative structure-activity relationship (QSAR) analysis. Finally, the compound H2 was picked out from those filtering compounds based on the receptor-ligand interaction analysis and the prediction of the QSAR models. And then it was submitted for molecular dynamics (MD) simulations to explore the stability of complex. The result indicates that the candidate could be considered a potential AMPK activator.

Molecular modeling and identification of novel glucokinase activators through stepwise virtual screening.

The glucose phosphorylating enzyme glucokinase (GK) is a 50kD monomeric protein having 465 amino acids. It maintains glucose homeostasis inside cells, acts as a glucose sensor in pancreatic ß-cells and as a rate controlling enzyme for hepatic glucose clearance and glycogen synthesis. It has two binding sites, one for binding d-glucose and the other for a putative allosteric activator named glucokinase activator (GKA). The GKAs interact with the same region of the GK enzyme that is commonly affected by naturally occurring mutations in humans. However, many GKAs do not bind to GK in the absence of glucose. Recently, it has been reported that GKAs are highly effective in patients with type 2 diabetes mellitus. In this milieu a molecular modeling study has been carried out on three natural variants of GK that lie in the GKA binding site and are known to cause maturity onset diabetes of young (MODY). Additionally, a 10ns molecular dynamics simulation was done on each of the modeled variant in order to explore the flexibility of this site. Subsequently, a systematic virtual screening study was done to identify compounds which can bind with high affinity at GKA binding site of mutant GK.

Comparison of the circulating metabolite profile of PF-04991532, a hepatoselective glucokinase activator, across preclinical species and humans: potential implications in metabolites in safety testing assessment.

A previous report from our laboratory disclosed the identification of PF-04991532 [(S)-6-(3-cyclopentyl-2-(4-trifluoromethyl)-1H-imidazol-1-yl)propanamido)nicotinic acid] as a hepatoselective glucokinase activator for the treatment of type 2 diabetes mellitus. Lack of in vitro metabolic turnover in microsomes and hepatocytes from preclinical species and humans suggested that metabolism would be inconsequential as a clearance mechanism of PF-04991532 in vivo. Qualitative examination of human circulating metabolites using plasma samples from a 14-day multiple ascending dose clinical study, however, revealed a glucuronide (M1) and monohydroxylation products (M2a and M2b/M2c) whose abundances (based on UV integration) were greater than 10% of the total drug-related material. Based on this preliminary observation, mass balance/excretion studies were triggered in animals, which revealed that the majority of circulating radioactivity following the oral administration of [¹4C]PF-04991532 was attributed to an unchanged parent (>70% in rats and dogs). In contrast with the human circulatory metabolite profile, the monohydroxylated metabolites were not detected in circulation in either rats or dogs. Available mass spectral evidence suggested that M2a and M2b/M2c were diastereomers derived from cyclopentyl ring oxidation in PF-04991532. Because cyclopentyl ring hydroxylation on the C-2 and C-3 positions can generate eight possible diastereomers, it was possible that additional diastereomers may have also formed and would need to be resolved from the M2a and M2b/M2c peaks observed in the current chromatography conditions. In conclusion, the human metabolite scouting study in tandem with the animal mass balance study allowed early identification of PF-04991532 oxidative metabolites, which were not predicted by in vitro methods and may require additional scrutiny in the development phase of PF-04991532.

[Research progress of effect of anti-diabetic traditional Chinese medicines based on regulation of glucose metabolic enzyme].

Diabetes is a global threat threatening human health in the world, with an increasing incidence rate in recent years. The disorder of glucose metabolism is one of the major factors. As relevant glucose metabolic enzymes such as alpha-glucosidase, glucose-6-phosphatase (G-6-P), glycogen phosphorylase (GP) and glycogen synthase kinase-3 (GSK-3) get involved in and control the process of glucose metabolism, the regulation of the activity of glucose metabolic enzymes is of significance to the treatment of diabetes. Traditional Chinese medicines (TCMs) have been widely researched because of their low toxicology and high efficiency, and many extracts and components from TCMs have been proven to be regulators of glucose metabolic enzymes. Compared with anti-diabetic western medicines, anti-diabetic TCMs feature safety, reliability and low price. This essay summarizes the anti-diabetic effect of TCMs on regulating glucose metabolic enzymes.

Effects of resin or charcoal treatment on fetal bovine serum and bovine calf serum.

INTRODUCTION: Charcoal- or resin-stripping of fetal bovine serum (FBS) or bovine calf serum (BCS) intended for supplementation of cell culture media is widely practiced to remove a variety of endogenous compounds, including steroid, peptide, and thyroid hormones. The possibility that stripping removes other biologically relevant factors from serum may not be appreciated. METHODS: In this report, standardized clinical laboratory testing methods were used to assess the effects of resin- and charcoal-stripping on content in FBS and BCS of more than 25 analytes in the sera. RESULTS AND CONCLUSION: In addition to hormones, the serum constituents affected by stripping are certain vitamins, electrolytes, enzyme activities, and metabolites.