A novel chemical uncoupler ameliorates obesity and related phenotypes in mice with diet-induced obesity by modulating energy expenditure and food intake.

AIMS/HYPOTHESIS: Decreasing mitochondrial coupling efficiency has been shown to be an effective therapy for obesity and related metabolic symptoms. Here we identified a novel mitochondrial uncoupler that promoted uncoupled respiration in a cell type-specific manner and investigated its effects on modulation of energy metabolism in vivo and in vitro.

METHODS

We screened a collection of mitochondrial membrane potential depolarising compounds for a novel chemical uncoupler on isolated skeletal muscle mitochondria using a channel oxygen system. The effect on respiration of metabolic cells (L6 myotubes, 3T3-L1 adipocytes and rat primary hepatocytes) was examined and metabolic pathways sensitive to cellular ATP content were also evaluated. The chronic metabolic effects were investigated in high-fat diet-induced obese mice and standard diet-fed (SD) lean mice.

RESULTS

The novel uncoupler, CZ5, promoted uncoupled respiration in a cell type-specific manner. It stimulated fuel oxidation in L6 myotubes and reduced lipid accumulation in 3T3-L1 adipocytes but did not affect gluconeogenesis or the triacylglycerol content in hepatocytes. The administration of CZ5 to SD mice increased energy expenditure (EE) but did not affect body weight or adiposity. Chronic studies in mice on high-fat diet showed that CZ5 reduced body weight and improved glucose and lipid metabolism via both increased EE and suppressed energy intake. The reduced adiposity was associated with the restoration of expression of key metabolic genes in visceral adipose tissue.

CONCLUSIONS/INTERPRETATION: This work demonstrates that a cell type-specific mitochondrial chemical uncoupler may have therapeutic potential for treating high-fat diet-induced metabolic diseases.