Type I neuregulin1? is a novel local mediator to suppress hepatic gluconeogenesis in mice.

ABSTRACT: Neuregulin1 is an epidermal growth factor (EGF)-like domain-containing protein that has multiple isoforms and functions as a local mediator in the control of various cellular functions. Here we show that type I isoform of neuregulin1 with an ?-type EGF-like domain (Nrg1?) is the major isoform in mouse liver and regulates hepatic glucose production. Forced expression of Nrg1? in mouse liver enhanced systemic glucose disposal and decreased hepatic glucose production with reduced fasting blood glucose levels. Nuclear forkhead box protein O1 (FoxO1) and its downstream targets, PEPCK and G6Pase, were suppressed in liver and isolated hepatocytes by Nrg1? overexpression. In contrast, silencing of Nrg1? enhanced glucose production with increased PEPCK and G6Pase expressions in cAMP/dexamethasone-stimulated hepatocytes. Mechanistically, the recombinant ?-type EGF-like domain of NRG1? (rNRG1?) stimulated the ERBB3 signalling pathway in hepatocytes, resulting in decreased nuclear FoxO1 accumulation via activation of both the AKT and ERK pathways. In addition, acute treatment with rNRG1? also suppressed elevation of blood glucose levels after both glucose and pyruvate challenge. Although a liver-specific deletion of Nrg1 gene in mice showed little effect on systemic glucose metabolism, these results suggest that NRG1? have a novel regulatory function in hepatic gluconeogenesis by regulating the ERBB3-AKT/ERK-FoxO1 cascade.

SUBMITTER: Arai T 

PROVIDER: S-EPMC5317163 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature