Glucokinase plays an important role in regulating the blood glucose level and serves as an essential therapeutic target in type 2 diabetes management. Entada africana is a medicinal plant and highly rich source of bioactive ligands with the potency to develop new target drugs for glucokinase such as diabetes and obesity. Therefore, the study explored a computational approach to predict identified compounds from Entada africana following its intermolecular interactions with the allosteric binding site of the enzymes. We retrieved the three-dimensional (3D) crystal structure of glucokinase (PDB ID: 4L3Q) from the online protein data bank and prepared it using the Maestro 13.5, Schrödinger Suite 2022-3. The compounds identified were subjected to ADME, docking analysis, pharmacophore modeling, and molecular simulation. The results show the binding potential of the identified ligands to the amino acid residues, thereby suggesting an interaction of the amino acids with the ligand at the binding site of the glucokinase activator through conventional chemical bonds such as hydrogen bonds and hydrophobic interactions. The compatibility of the molecules was highly observed when compared with the standard ligand, thereby leading to structural and functional changes. Therefore, the bioactive components from Entada africana could be a good driver of glucokinase, thereby paving the way for the discovery of therapeutic drugs for the treatment of diabetes and its related complications.
A mathematical model to describe the oscillatory bursting activity of pancreatic beta-cells is combined with a model of glucose regulation system in this work to study the bursting pattern under regulated extracellular glucose stimulation. The bursting electrical activity in beta-cells is crucial for the release of insulin, which acts to regulate the blood glucose level. Different types of bursting pattern have been observed experimentally in glucose-stimulated islets both in vivo and in vitro, and the variations in these patterns have been linked to changes in glucose level. The combined model in this study enables us to have a deeper understanding on the regime change of bursting pattern when glucose level changes due to hormonal regulation, especially in the postprandial state. This is especially important as the oscillatory components of electrical activity play significant physiological roles in insulin secretion and some components have been found to be lost in type 2 diabetic patients.
Pluripotent stem cells may serve as an alternative source of beta-like cells for replacement therapy of type 1 diabetes; however, the beta-like cells generated in many differentiation protocols are immature. The maturation of endogenous beta cells involves an increase in insulin expression starting in late gestation and a gradual acquisition of the abilities to sense glucose and secrete insulin by week 2 after birth in mice; however, what molecules regulate these maturation processes are incompletely known. In this study, we aim to identify small molecules that affect immature beta cells. A cell-based assay, using pancreatic beta-like cells derived from murine embryonic stem (ES) cells harboring a transgene containing an insulin 1-promoter driven enhanced green fluorescent protein reporter, was used to screen a compound library (NIH Clinical Collection-003). Cortisone, a glucocorticoid, was among five positive hit compounds. Quantitative reverse transcription-polymerase chain reaction analysis revealed that glucocorticoids enhance the gene expression of not only insulin 1 but also glucose transporter-2 (Glut2; Slc2a2) and glucokinase (Gck), two molecules important for glucose sensing. Mifepristone, a pharmacological inhibitor of glucocorticoid receptor (GR) signaling, reduced the effects of glucocorticoids on Glut2 and Gck expression. The effects of glucocorticoids on ES-derived cells were further validated in immature primary islets. Isolated islets from 1-week-old mice had an increased Glut2 and Gck expression in response to a 4-day treatment of exogenous hydrocortisone in vitro. Gene deletion of GR in beta cells using rat insulin 2 promoter-driven Cre crossed with GRflox/flox mice resulted in a reduced gene expression of Glut2, but not Gck, and an abrogation of insulin secretion when islets were incubated in 0.5 mM d-glucose and stimulated by 17 mM d-glucose in vitro. These results demonstrate that glucocorticoids positively regulate glucose sensors in immature murine beta-like cells.