Type 2 diabetes mellitus (T2DM) is associated with a high incidence of non-alcoholic fatty liver disease (NAFLD) related to obesity and insulin resistance. Currently, medical interventions for NAFLD have focused on diet control and exercise to reduce body weight, and there is a requirement for effective pharmacological therapies. Sodium-glucose cotransporter 2 (SGLT2) inhibitors are oral antidiabetic drugs that promote the urinary excretion of glucose by blocking its reabsorption in renal proximal tubules. SGLT2 inhibitors lower blood glucose independent of insulin action and are expected to reduce body weight because of urinary calorie loss. Here we show that an SGLT2 inhibitor ipragliflozin improves hepatic steatosis in high-fat diet-induced and leptin-deficient (ob/ob) obese mice irrespective of body weight reduction. In the obese mice, ipragliflozin-induced hyperphagia occurred to increase energy intake, attenuating body weight reduction with increased epididymal fat mass. There is an inverse correlation between weights of liver and epididymal fat in ipragliflozin-treated obese mice, suggesting that ipragliflozin treatment promotes normotopic fat accumulation in the epididymal fat and prevents ectopic fat accumulation in the liver. Despite increased adiposity, ipragliflozin ameliorates obesity-associated inflammation and insulin resistance in epididymal fat. Clinically, ipragliflozin improves liver dysfunction in patients with T2DM irrespective of body weight reduction. These findings provide new insight into the effects of SGLT2 inhibitors on energy homeostasis and fat accumulation and indicate their potential therapeutic efficacy in T2DM-associated hepatic steatosis.

By interacting with the collagen cargo receptor component cTAGE5, Sec12 concentrates at ER exit sites and generates the high levels of GTP-bound Sar1 necessary for export of collagen to the Golgi.

Sodium glucose cotransporter 2 (SGLT2) inhibitors, an antidiabetic drug, promotes urinary excretion of glucose by blocking its reabsorption in the renal proximal tubules. It is unclear whether SGLT2 inhibition could attenuate nonalcoholic steatohepatitis (NASH) and NASH-associated hepatocellular carcinoma. We examined the preventive effects of an SGLT2 inhibitor canagliflozin (CANA) in Western diet (WD)-fed melanocortin 4 receptor-deficient (MC4R-KO) mice, a mouse model of human NASH. An eight-week CANA treatment attenuated hepatic steatosis in WD-fed MC4R-KO mice, with increased epididymal fat mass without inflammatory changes. CANA treatment for 20 weeks inhibited the development of hepatic fibrosis in WD-fed MC4R-KO mice. After one year of CANA treatment, the number of liver tumors was significantly reduced in WD-fed MC4R-KO mice. In adipose tissue, CANA suppressed the ratio of oxidative to reduced forms of glutathiones (GSSG/GSH) in WD-fed MC4R-KO mice. Treatment with GSH significantly attenuated the H2O2-induced upregulation of genes related to NADPH oxidase in 3T3-L1 adipocytes, and that of Il6, Tgfb, and Pdgfb in RAW264.7 cells. This study provides evidence that SGLT2 inhibitors represent the unique class of drugs that can attenuate or delay the onset of NASH and eventually hepatocellular carcinoma, at least partly, through “healthy adipose expansion”.

Obesity promotes infiltration of inflammatory cells into various tissues, leading to parenchymal and stromal cell interaction and development of cellular and organ dysfunction. Liver sinusoidal endothelial cells (LSECs) are the first cells that contact portal blood cells and substances in the liver, but their functions in the development of obesity-associated glucose metabolism remain unclear. Here, we find that LSECs are involved in obesity-associated accumulation of myeloid cells via VLA-4-dependent cell-cell adhesion. VLA-4 blockade in mice fed a high-fat diet attenuated myeloid cell accumulation in the liver to improve hepatic inflammation and systemic glucose intolerance. Ex vivo studies further show that cell-cell contact between intrahepatic leukocytes and parenchymal hepatocytes induces gluconeogenesis via a Notch-dependent pathway. These findings suggest that cell-cell interaction between parenchymal and stromal cells regulates hepatic glucose metabolism and offers potential strategies for treatment or prevention of obesity-associated glucose intolerance.

Non-alcoholic steatohepatitis (NASH) is characterized by steatosis with lobular inflammation and hepatocyte injury. Pirfenidone (PFD) is an orally bioavailable pyridone derivative that has been clinically used for the treatment of idiopathic pulmonary fibrosis. However, it remains unknown whether PFD improves liver fibrosis in a mouse model with human NASH-like phenotypes. In this study, we employed melanocortin 4 receptor-deficient (MC4R-KO) mice as a mouse model with human NASH-like phenotypes to elucidate the effect and action mechanisms of PFD on the development of NASH. PFD markedly attenuated liver fibrosis in western diet (WD)-fed MC4R-KO mice without affecting metabolic profiles or steatosis. PFD prevented liver injury and fibrosis associated with decreased apoptosis of liver cells in WD-fed MC4R-KO mice. Pretreatment of PFD inhibited the tumor necrosis factor-α (TNF-α)-induced liver injury and fibrogenic responses associated with decreased apoptosis of liver cells in wild-type mice. PFD also prevented TNF-α-induced hepatocyte apoptosis in vitro with reduced activation of caspase-8 and -3. This study provides evidence for the antifibrotic effect of PFD in a mouse model of human NASH. The data of this study highlight hepatocyte apoptosis as a potential therapeutic target, and suggest that PFD can be repositioned as an antifibrotic drug for human NASH.