RNA-seq of metformin treatment in primary murine hepatocytes in WT, Raptor Ser-Ala mutant, Tsc2-null, Raptor mutant;Tsc2-null, and Ampk-null cells

Despite being the frontline therapy for Type 2 diabetes, the mechanisms of action of the biguanide drug metformin are still being discovered. In particular, the detailed molecular interplays between the AMPK and the mTORC1 pathway in the hepatic benefits of metformin are still ill-defined. Metformin-dependent activation of AMPK classically inhibits mTORC1 via TSC/RHEB. But several lines of evidence suggest additional mechanisms at play in metformin inhibition of mTORC1. Here we investigated the role of direct AMPK-mediated serine phosphorylation of RAPTOR in a new RaptorAA mouse model, in which AMPK phospho-serine sites Ser722 and Ser792 of RAPTOR were mutated to alanine. Metformin treatment of primary hepatocytes and intact murine liver requires AMPK regulation of both RAPTOR and TSC2 to fully inhibit mTORC1, and this regulation is critical for the transcriptional response to metformin. Transcriptionally, AMPK and mTORC1 were both important for regulation of anabolic metabolism and inflammatory programs triggered by metformin treatment. Overall design: 5h treatment of 2mM Metformin or 0.1uM INK-128 in serum-starved primary murine hepatocytes in the absence or presence of 15 minute pre-treatment with 1nM Insulin