Disruption of the glucagon receptor increases glucagon expression beyond α-cell hyperplasia in zebrafish

Stilbenoids from fenugreek seeds alleviate insulin resistance by regulating the PI3K/AKT/mTOR signaling pathway in a type 2 diabetes zebrafish model

Insulin resistance (IR) is the main cause of type 2 diabetes mellitus (T2DM). The specific targets and underlying mechanisms responsible for the ameliorative effects of the stilbenoid compounds found in fenugreek seeds for ameliorating IR require further study. Here, we were predicted by using the network pharmacology prediction, molecular docking and molecular dynamics simulation approach the targets in common and the potential mechanismsof three stilbenoid compounds (rhaponticin, desoxyrhaponticin, and rhapontigenin) in relation to T2DM and IR. The results showed that the compounds may improve IR through the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway. Molecular docking studies revealed that they exhibit high binding affinity with the structural domains of peroxisome proliferator-activated receptor gamma (PPARG), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), PI3K, and AKT. These results suggest that PPARG and GAPDH may be the potential targets for these three compounds in the treatment of T2DM.Subsequently, experiments using the zebrafish T2DM model showed that the stilbenoid compounds had varying degrees of efficacy in improving IR through the PI3K/AKT/mTOR signaling pathway, and rhaponticin had the most promising effects. The findings implicate a potential mechanism of action for the three stilbenoid compounds in enhancing insulin resistance (IR) through modulation of the PI3K/AKT/mTOR pathway.

Crispr-Cas9 mediated complete deletion of glucagon receptor in mice display hyperglucagonemia and α-cell hyperplasia

Glucagon receptor plays an important role in the regulation of glucose metabolism. Studies have revealed that glucagon receptor antagonism is a potential effective treatment for diabetes. However, the functions of GCGR have not been fully illustrated. Although two Gcgr truncation knockout mice models have been widely used for GCGR function studies, truncated gene may remain neomorphic and/or dominant-negative function. In this study, we took the advantages of Crispr-Cas9 technique and generated a novel allele of GCGR in the mouse that yields complete loss of GCGR protein. Our studies reveal that complete deletion of Gcgr results in hyperglucagonemia, α-cell hyperplasia, improvement of glucose tolerance. These results are similar to the Gcgr-truncated mutation in mice. Hence, we provide a novel strain of GCGR knockout mice for the GCGR function studies.