Pluto Bioinformatics

GSE89035: Interruption of Hepatic Glucagon Signaling Reveals a Hepatic--Islet Cell Axis Where L-Glutamine Stimulates -Cell Proliferation

Bulk RNA sequencing

Decreasing glucagon action lowers blood glucose and may be a useful therapeutic approach for diabetes. However, interrupted glucagon signaling in mice leads to hyperglucagonemia and -cell hyperplasia.We show using islet transplantation, mouse and zebrafish models, an in vitro islet culture assay that a hepatic-derived, circulating factor in mice with interrupted glucagon signaling stimulates -cell proliferation, which was dependent on mTOR signaling and the FoxP transcription factors. -cells of transplanted human islets also proliferated in response to this signal in mice. A combination of liver transcriptomics and serum fractionation with proteomics/metabolomics found changes in hepatic gene expression relating to amino acid catabolism predicting the observed increase in serum amino acid levels.Amino acid concentrations that mimicked the levels in mice with interrupted glucagon signaling, specifically L-glutamine, stimulated -cell proliferation. These results indicate a hepatic--islet cell axis where glucagon regulates serum amino acid availability and L-glutamine regulates -cell proliferation via mTOR-dependent nutrient sensing. SOURCE: Danielle Dean (danielle.dean@vanderbilt.edu) - Vanderbilt University Medical Center