Expression of BMP4 in myocardium and vascular tissue of obese mice

BACKGROUND: Obesity is regarded as a risk factor for cardiovascular disease. Bone morphogenetic protein 4 (BMP4) is a proinflammatory and profibrotic factor, and the reduced expression of this molecule in obese mice seems to be inconsistent with the known proinflammatory effects of obesity. Therefore, we studied BMP4 expression and inflammation in the myocardial tissue and aortas of obese mice. METHODS AND RESULTS: Four-week-old ob/ob mice were used as the experimental group, and C57BL/6 mice comprised the control group. Animals were sacrificed after a 12-week full diet, and then the blood, heart, abdominal aorta, and inguinal adipose tissue were collected. The expression of BMP4 mRNA and protein in the heart and aorta was significantly higher in the experimental group than in the control group, but expression was lower in adipose tissue. Inflammation measured by the expression of IL-1β and IL-9 mRNA and protein and Smad1 and phosphorylated Smad1/5/8 protein in the heart and aorta was higher in the experimental group than in the control group. In addition, the expression of BMP4 in the serum was significantly higher in the experimental group than in the control group. CONCLUSION: BMP4 is significantly overexpressed in the myocardial tissue and aortas of obese mice, and mediates local inflammatory responses.