Adipose tissue Mest and Sfrp5 are concomitant with variations of adiposity among inbred mouse strains fed a non-obesogenic diet.

The expression of a subset of genes including mesoderm specific transcript (Mest), secreted frizzled-related protein 5 (Sfrp5) and bone morphogenetic protein 3 (Bmp3) in adipose tissue biopsies of C57BL/6J mice before exposure to an obesogenic diet were shown to be predictive for the development of obesity in mice after feeding a high fat diet for 8 weeks. This observation led to the supposition that adipose tissue expression of this subset of genes within inbred strains of mice could be associated with their susceptibility in the development of adiposity when fed a low fat diet. The analyses of male mice from 5 inbred strains showed average bodyweights ranging from 25.82 to 36.58 g at 16 weeks of age. Bodyweight was highest for AKR/J and adiposity correlated highly with bodyweight for all strains. Analyses of epididymal fat gene expression showed Mest, Sfrp5 and Bmp3 to be highly concomitant with adiposity across all strains of mice. Naked 1 (Nkd1), a gene previously shown to be associated with variations of adiposity in mice fed a high fat diet, but not predictive for the development of adiposity, showed no correlation with adiposity. In addition, the expression of Mest and Sfrp5 were tightly associated across the 5 mouse strains with the highest and lowest expression occurring in DBA/2J and C57BL/6J (B6) respectively suggesting a common mechanism for their regulation. Surprisingly, when independent cohorts for these 2 strains were fed high fat diet for 8 weeks, DBA/2J showed no further increase in Sfrp5 expression whereas expression levels for B6 mice were induced almost 20-fold. Analyses of (B6 x DBA2/J) F1 mice fed a low fat diet for 8 weeks showed intermediate levels of adiposity and gene expression for Sfrp5 and Mest suggesting a strong genetic basis for these differences.