Inhibition of Bone Morphogenic Protein 4 Restores Endothelial Function in db/db Diabetic Mice

Objective-Bone morphogenic protein 4 (BMP4) is involved in the development of endothelial dysfunction in hypertension. This study investigated whether the inhibition of BMP4 signaling improves endothelial function in db/db diabetic mice. Approach and Results-Male db/db mice were treated with noggin via osmotic pump infusion (1 mu g/[h.kg(-1)]) for 2 weeks. Adenovirus BMP4-short hairpin RNA was introduced via tail vein injection at a dosage of 10(9) pfu/mouse and its effects were examined 7 days after. Vasoreactivity was studied on wire and pressure myograph. Both noggin treatment and adenovirus BMP4-short hairpin RNA transduction improved endothelium-dependent relaxations in aortae and flow-mediated dilatation in mesenteric arteries of db/db mice. Ex vivo treatment with BMP4 inhibitors and adenovirus BMP4-short hairpin RNA rescued the impaired endothelium-dependent relaxations in db/db mouse aortae and reduced reactive oxygen species overproduction determined by dihydroethidium staining, CM-H(2)DCFDA fluorescence imaging, and chemiluminescence assay in db/db mouse aortae, and also in ex vivo cultured C57BL/6 mouse aortae or primary mouse aortic endothelial cells treated with high glucose. Likewise, activin receptor-like kinase 3 silencing by short hairpin RNA lentivirus improved endothelium-dependent relaxations in db/db mouse aortae accompanied by reactive oxygen species inhibition in endothelial cells. In addition, noggin reduced BMP4 upregulation in high-glucose-treated endothelial cells and in C57BL/6 mouse aortae and in aortae from db/db mice. Conclusions-Inhibition of BMP4/activin receptor-like kinase 3/reactive oxygen species signaling improved endothelial function in diabetic mice through limiting oxidative stress in endothelium. Inhibiting BMP4 cascade can become another potential therapeutic strategy against diabetic vascular dysfunction.