2C). Their lean mass was also similar (Fig. Navitoclax mouse 2D). There was also no difference in the adiposity

index in HSD-fed or HFD-fed Pnpla3+/+ and Pnpla3−/− mice (data not shown). In addition, we detected no difference in the weights of gonadal, subcutaneous, or brown adipose depots in Pnpla3+/+ and Pnpla3−/− mice (data not shown). Experiments on the in vitro differentiation of stromal vascular cells isolated from Pnpla3+/+ and Pnpla3−/− mice revealed no difference in the efficiency of adipocyte differentiation or TG accumulation between the two genotypes (Supporting Fig. 1A,B), which agrees with the fact that the adipose depot mass was similar in these mice. Furthermore, the basal and β-adrenergic agonist–stimulated lipolysis in fully differentiated stromal vascular cells in vitro (Supporting Fig. 1C,D) as well as in mice in vivo (Supporting Fig. 1E,F) was similar between wild-type and Pnpla3−/− cells or mice, indicating that, unlike

ATGL and hormone-sensitive Ivacaftor order lipase, Pnpla3 does not contribute significantly to basal or β-adrenergic agonist–stimulated lipolysis. The nonsynonymous rs738409 SNP in PNPLA3 was predicted to cause the loss of PNPLA3 enzymatic activity, a consequence functionally similar to the targeted inactivation of Pnpla3 in our mouse model.3-6 Microscopic examination of Pnpla3−/− mouse liver sections revealed normal histology (data not shown). We analyzed liver TG content in wild-type and Pnpla3−/− mice fed regular chow, and after they had been placed on three different fatty liver–inducing diets. As shown in Table 1, mice in C57BL/6 background

fed the different fatty liver–inducing diets (including HSD, HFD, and MCD diets) displayed varying degrees of increased liver TG content compared with mice fed CHD. However, there was no significant difference in the degree of hepatic TG accumulation between wild-type and Pnpla3−/− mice under each type of diet, indicating that loss of Pnpla3 had no direct impact on liver TG accumulation. Genetic variations at PNPLA3 have been reported to be associated with increased serum levels of liver enzymes in human populations.3, 5 We found that serum ALT and AST levels varied with the diet conditions (Table 1), being highest in mice fed an MCD diet, which Glycogen branching enzyme may be related to the significant liver damage and inflammation induced by this diet. However, no difference in ALT or AST level was observed between the two genotypes, suggesting that lack of Pnpla3 in mice does not cause an elevated aminotransferase response in liver either under CHD or after the mice were fed the different fatty liver–inducing diets. To further analyze whether loss of Pnpla3 affects fatty liver development associated with a genetic form of obesity, we intercrossed the Lepob/+ mice with Pnpla3−/− mice to produce Lepob/ob/Pnpla3+/+ and Lepob/ob/Pnpla3−/− mice. The obesity phenotype was unchanged in these mice.