Deficiency of bone morphogenetic protein-3b induces metabolic syndrome and increases adipogenesis

Abstract

Bone morphogenetic protein (BMP) receptor signaling is critical for the regulation of the endocrine system and cardiovascular structure and function. The objective of this study was to investigate whether Bmp3b, a glycoprotein synthetized and secreted by adipose tissue, is necessary to regulate glucose and lipid metabolism, adipogenesis, and cardiovascular remodeling. Over the course of 4 mo, <i>Bmp3b</i>-knockout (<i>Bmp3b^-/-</i>) mice gained more weight than wild-type (WT) mice. The plasma levels of cholesterol and triglycerides were higher in <i>Bmp3b^-/-</i> mice than in WT mice. <i>Bmp3b^-/-</i> mice developed insulin resistance and glucose intolerance. The basal heart rate was higher in <i>Bmp3b^-/-</i> mice than in WT mice, and echocardiography revealed eccentric remodeling in <i>Bmp3b^-/-</i> mice. The expression of adipogenesis-related genes in white adipose tissue was higher in <i>Bmp3b^-/-</i> mice than in WT control mice. In vitro studies showed that Bmp3b modulates the activity of the <i>C/ebpα</i> promoter, an effect mediated by Smad2/3. The results of this study suggest that Bmp3b is necessary for the maintenance of homeostasis in terms of age-related weight gain, glucose metabolism, and left ventricular (LV) remodeling and function. Interventions that increase the level or function of BMP3b may decrease cardiovascular risk and pathological cardiac remodeling.