Bone morphogenic protein-4-induced oxidant signaling via protein carbonylation for endothelial dysfunction.

The increased expression of bone morphogenic protein-4 (BMP-4) under hyperglycemic and diabetic conditions mediates the overgeneration of reactive oxygen species to cause endothelial cell dysfunction and apoptosis. Protein carbonylation plays an important role in oxidant signaling through ligand-receptor interactions in vascular smooth muscle cells, cardiac cells, and bronchial smooth muscle cells to trigger different diseases. However, the role of oxidant signaling via protein carbonylation in endothelial dysfunction is unclear. The level of protein carbonylation was higher in renal arteries from diabetic patients than those from nondiabetic subjects. BMP-4 promoted protein carbonylation, which was followed by decarbonylation or degradation in primary rat aortic endothelial cells. Organ culture of normal C57BL/6J mouse aortas treated with either hydralazine or deferoxamine inhibited the effect of BMP-4 on impairment of acetylcholine-induced endothelium-dependent relaxation (EDR). In isolated diabetic db/db mouse aortas, treatment with hydralazine improved the impaired EDR while deferoxamine had no effect. BMP-4-induced carbonylated proteins in aortic endothelial cells were successfully identified by a proteomic approach. These proteins have important cellular functions and include glyceraldehyde-3-phosphate dehydrogenase, triosephosphate isomerase, alpha-enolase, protein disulfide-isomerase A3, annexin II, 26S protease regulatory subunit, integrin-linked protein kinase, and vimentin. Protein carbonylation induced by BMP-4 was inhibited by BMP-4 antagonist while protein decarbonylation induced by BMP-4 was thiol dependent. The carbonyl signals did not involve 4-hydrononenal and malondialdehyde. The present results suggest that BMP-4- or diabetes-mediated endothelial dysfunction is partly triggered through protein carbonylation and blockade of this metal-catalyzed protein oxidation can be considered as an alternative therapeutic strategy to alleviate diabetic vasculopathy.

Wong CM ，Zhang Y ，Huang Y 《-》

Inhibition of bone morphogenic protein 4 restores endothelial function in db/db diabetic mice.

Zhang Y ，Liu J ，Tian XY ，Wong WT ，Chen Y ，Wang L ，Luo J ，Cheang WS ，Lau CW ，Kwan KM ，Wang N ，Yao X ，Huang Y ... -  《-》

Bone Morphogenic Protein 4-Smad-Induced Upregulation of Platelet-Derived Growth Factor AA Impairs Endothelial Function.

Bone morphogenic protein 4 (BMP4) is an important mediator of endothelial dysfunction in cardio-metabolic diseases, whereas platelet-derived growth factors (PDGFs) are major angiogenic and proinflammatory mediator, although the functional link between these 2 factors is unknown. The present study investigated whether PDGF mediates BMP4-induced endothelial dysfunction in diabetes mellitus. We generated Ad-Bmp4 to overexpress Bmp4 and Ad-Pdgfa-shRNA to knockdown Pdgfa in mice through tail intravenous injection. SMAD4-shRNA lentivirus, SMAD1-shRNA, and SMAD5 shRNA adenovirus were used for knockdown in human and mouse endothelial cells. We found that PDGF-AA impaired endothelium-dependent vasodilation in aortas and mesenteric resistance arteries. BMP4 upregulated PDGF-AA in human and mouse endothelial cells, which was abolished by BMP4 antagonist noggin or knockdown of SMAD1/5 or SMAD4. BMP4-impared relaxation in mouse aorta was also ameliorated by PDGF-AA neutralizing antibody. Tail injection of Ad-Pdgfa-shRNA ameliorates endothelial dysfunction induced by Bmp4 overexpression (Ad-Bmp4) in vivo. Serum PDGF-AA was elevated in both diabetic patients and diabetic db/db mice compared with nondiabetic controls. Pdgfa-shRNA or Bmp4-shRNA adenovirus reduced serum PDGF-AA concentration in db/db mice. PDGF-AA neutralizing antibody or tail injection with Pdgfa-shRNA adenovirus improved endothelial function in aortas and mesenteric resistance arteries from db/db mice. The effect of PDGF-AA on endothelial function in mouse aorta was also inhibited by Ad-Pdgfra-shRNA to inhibit PDGFRα. The present study provides novel evidences to show that PDGF-AA impairs endothelium-dependent vasodilation and PDGF-AA mediates BMP4-induced adverse effect on endothelial cell function through SMAD1/5- and SMAD4-dependent mechanisms. Inhibition of PGDF-AA ameliorates vascular dysfunction in diabetic mice.

Hu W ，Zhang Y ，Wang L ，Lau CW ，Xu J ，Luo JY ，Gou L ，Yao X ，Chen ZY ，Ma RC ，Tian XY ，Huang Y ... -  《-》

Bone morphogenic protein-4 impairs endothelial function through oxidative stress-dependent cyclooxygenase-2 upregulation: implications on hypertension.

Wong WT ，Tian XY ，Chen Y ，Leung FP ，Liu L ，Lee HK ，Ng CF ，Xu A ，Yao X ，Vanhoutte PM ，Tipoe GL ，Huang Y ... -  《-》

Multidrug resistance associated protein-1 (MRP1) deficiency attenuates endothelial dysfunction in diabetes.

The multidrug resistance associated protein-1 (MRP1) is the main transporter of oxidized glutathione in endothelial cells, and blockade of MRP1 improves endothelial cell dysfunction induced by reactive oxygen species. We therefore investigated the role of MRP1 in hyperglycemia-induced endothelial dysfunction and ROS production. Diabetes was induced in 12 week old male MRP1(-/-)- or corresponding FVB wild-type (wt) mice by injection of streptozotocin (50mg/kg for 5 days). Eight weeks thereafter acetylcholine-induced endothelium-dependent vasorelaxation was blunted in aortic rings from diabetic wt mice (blood glucose levels >250 mg/dl) compared with nondiabetic animals (Rmax 74 ± 2% vs. 94 ± 2%, p<0.001). However in aortae from diabetic mice lacking MRP1, endothelium-dependent vasorelaxation was only mildly impaired (Rmax 87 ± 3%, p<0.001 vs. wt). Endothelium-independent relaxation induced by DEA-NONOate was not different among the groups. Streptozotocin-induced diabetes significantly increased aortic superoxide anion and hydrogen peroxide production in wild-type but not in MRP1(-/-) mice. Aortic levels of glutathione were significantly diminished in STZ-treated FVB mice, while preserved in MRP1(-/-) mice. Further, in cultured human aortic endothelial cells, high glucose levels (30 mmol/l) over 5 days significantly increased superoxide production which was inhibited by downregulation of MRP1 via siRNA. These data indicate that MRP1 plays an important role for endothelial dysfunction and reactive oxygen species production in diabetes and under conditions of hyperglycemia. MRP1 therefore may represent a therapeutic target in treatment of diabetes induced vascular dysfunction.

Neuser J ，Fraccarollo D ，Wick M ，Bauersachs J ，Widder JD ... -  《-》