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Bron, C.

Publications and source records attributed to Bron, C..

2 recordsLinked to original sources

Reducing the CAV1-dependent trafficking of G6PC1 in the liver protects against the development of type 2 diabetes

Targeting hepatic gluconeogenesis is an efficient strategy to counteract the development of type 2 diabetes. Hepatic glucose production into the bloodstream is controlled by the GLUT2 transporter and a vesicular pathway dependent on Caveolin-1 (CAV1) involving G6PC1 location at the plasma membrane. We hypothesized that decreasing hepatic gluconeogenesis by targeting CAV1 specifically in the liver (L.Cav1-/- mice) improves energy and glucose metabolism in diabetic mice. Here we show that the absence of hepatic CAV1 increases insulin sensitivity, glucose tolerance and decreases fasting hyperglycemia and hyperinsulinemia in mice feeding a high fat high sucrose diet (HFHS diet). The decrease in insulin sensitivity takes place also in L.Cav1-/- mice feeding a standard diet (STD diet). Moreover, we demonstrated an improvement of glycemic control when hepatic Cav1 is deleted in previously prediabetic mice. In parallel, the absence of CAV1 in the liver reduces body weight gain and lipid intestinal absorption. Together these findings highlight that the vesicular pathway of glucose production represents a promising therapeutic target in the prevention of type 2 diabetes.

physiology↗

Intestinal Gluconeogenesis Regulates Brown and White Adipose Tissues Functions in mice

ObjectiveIntestinal gluconeogenesis, via the initiation of a gut-brain nervous circuit, accounts for the metabolic benefits linked to dietary proteins or fermentable fibre in rodents and has been positively correlated with the rapid amelioration of body weight after gastric bypass surgery in obese humans. In particular, the activation of intestinal gluconeogenesis moderates the development of hepatic steatosis accompanying obesity. In this study, we investigated the specific effects of intestinal gluconeogenesis on adipose tissue metabolism, independently of its induction by nutritional manipulation. MethodsWe used two transgenic mouse models of suppression or overexpression of G6PC, the catalytic subunit of glucose-6 phosphatase, the key enzyme of endogenous glucose production, specifically in the intestine. ResultsUnder a hypercaloric diet, mice with a genetic overexpression of intestinal gluconeogenesis showed a lower adiposity and higher thermogenic capacities than wild-type mice, featuring marked browning of white adipose tissue and prevention of the whitening of brown adipose tissue. Suppression of sympathetic nervous signalling in brown adipose tissue impairs the activation of thermogenesis. Conversely, mice with genetic suppression of intestinal gluconeogenesis exhibit an increase in adiposity under standard diet, associated with a decreased expression of markers of thermogenesis in both the brown and white adipose tissues. ConclusionIntestinal gluconeogenesis is sufficient in itself to activate the sympathetic nervous system and prevent the expansion and the metabolic alterations of brown and white adipose tissues metabolism under high calorie diet, thus preventing the development of obesity. These data increase knowledge of the mechanisms of weight reduction in gastric bypass surgery and pave the way of new approaches to prevent or cure obesity.

physiology↗