Functional role of ADAMTS5 in adiposity and metabolic health.

Previous studies with gene-deficient mice (ADAMTS5-P) revealed that ADAMTS5 (A Disintegrin And Metalloproteinase with Thrombospondin type 1 motifs, member 5) plays a functional role in adiposity and metabolic health. To confirm these observations, we have performed similar studies with an independently generated strain of ADAMTS5 deficient mice (ADAMTS5-J). Upon cold exposure as well as after high-fat diet feeding (diet-induced obesity or DIO model), these knockout (KO) mice developed less subcutaneous and gonadal white adipose tissue (WAT) as compared to their wild-type (WT) littermates (reduction was more pronounced in ADAMTS5-P mice). Enhanced browning of WAT, as monitored by expression of UCP-1 was seen in the ADAMTS5-J KO mice upon cold exposure but not in the DIO model (seen in both conditions with the ADAMTS5-P mice). Brown adipose tissue (BAT) mass was not different between KO and WT ADAMTS5-J mice, either upon cold exposure or in the DIO model (in contrast to the enhanced BAT mass with the ADAMTS5-P mice). Energy expenditure and thermogenesis were not significantly different between KO and WT ADAMTS5-J mice (in contrast to somewhat enhanced levels in ADAMTS5-P mice). Insulin sensitivity was improved in the ADAMTS5-J KO mice, and they were protected against non-alcoholic steatohepatitis in the DIO model (as the ADAMTS5-P mice). These data are thus similar for both strains of KO mice, confirming specificity of the phenotype, but some quantitative and qualitative differences are also observed.