PPARD and diabetic cardiomyopathy: Given the critical role of cardiac PPARα, PPARβ, and PPARγ1 in diabetic cardiomyopathy [31], we next challenged MuRF3−/− mice to a high fat diet (60 % fat, 20 % protein, and 20 % carbohydrates) for 26 weeks (Fig. 1b) as previously described [15].