SGLT2 Inhibitor Canagliflozin Triggers Hepatic Transcriptional Reprogramming and Impacts Systemic Metabolism in Mice with Diet-Induced Obesity

To determine the impact of SGLT2 inhibition and reduction in plasma glucose on transcriptional and metabolic responses, we fed normoglycemic C57BL/6J mice a 60% HFD for 4 weeks prior to assignment to one of 3 groups (n=12/group): (1) HFD ad libitum (HFD), (2) HFD ad libitum with canagliflozin (CANA, 30mg/kg/day), and (3) HFD weight-matched to CANA-treated mice via caloric restriction (CR). Fasting plasma glucose was reduced by 68 mg/dl (p<0.001) and body weight reduced by 5 g (p<0.001) in CANA vs. HFD. Fat mass was reduced in CANA vs. HFD (Δ-2 g by DEXA, p=0.03). Mice were sacrificed after an overnight fast after 4 weeks. Severe hepatic steatosis was reduced in CANA vs. HFD (Grade 3, >66% of parenchyma, X2 p=0.056) but no change in triglyceride content (4.3 ± 1.7 vs. 3.7 ± 1.2 mg/g tissue, p=0.85). To evaluate transcriptional responses to resolution of glucotoxicity, RNA was extracted from liver and processed for microarray analysis (Mouse Gene 2.0 ST). 2048 genes were differentially expressed between CANA and HFD (p<0.05). Pathway analysis revealed downregulation of de novo lipogenesis, glycolysis and steroid biosynthesis, and upregulation of TCA cycle and electron transport chain (p<0.05). Parallel targeted metabolite profiling (LC/MS) revealed significant changes in 31 metabolites and 59 lipid species (p<0.05). Among these, deoxycholic acid, C3 malonyl-canitine, malonic acid, and the ketones acetoacetate and β-hydroxybutyrate were significantly higher in CANA. Moreover there were significant increases in polyunsaturated fatty acids within triglyceride fractions. Collectively, these data indicate that SGLT2 inhibition and sustained reduction in plasma glucose trigger altered hepatic transcriptional programs, inducing not only ketogenesis and oxidative catabolism but also reduced de novo lipogenesis, potentially via reduced activation of key lipid and carbohydrate regulatory transcription factors SREBP2 and ChREBP.