H&E sections of 2-week-old wild-type and transgenic mice expressing miR-195 under control of the αMHC promoter. In transgenic as compared with wild-type mice, moderate levels of miR-195 expression (26-fold) cause cardiac hypertrophy, and higher levels of expression (29-fold) cause dilated cardiomyopathy with ventricular dilatation and wall thinning. Reproduced with permission from Proceedings of the National Academy of Sciences of the United States of America (8). Scale bar: 2 mm.