期刊
DIABETES
卷 61, 期 7, 页码 1860-1868出版社
AMER DIABETES ASSOC
DOI: 10.2337/db11-1658
关键词
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资金
- American Diabetes Association [JFA-07-39, 1-12-BS-119]
- National Institutes of Health [HL-74180, HL-080118]
Activity of the vascular large conductance Ca2+-activated K (BK) channel is tightly regulated by its accessory beta(1) subunit (BK-beta(1)). Downregulation of BK-beta(1) expression in diabetic vessels is associated with upregulation of the forkhead box O subfamily transcription factor-3a (FOXO-3a) dependent F-box only protein (FBXO) expression. However, the upstream signaling regulating this process is unclear. Overproduction of reactive oxygen species (ROS) is a common finding in diabetic vasculopathy. We hypothesized that ROS signaling cascade facilitates the FOXO-3a/FBXO-mediated BK-beta(1) degradation and leads to diabetic BK channel dysfunction. Using cellular biology, patch clamp, and videomicroscopy techniques, we found that reduced BK-beta(1) expression in streptozotocin (STZ)-induced diabetic mouse arteries and in human coronary smooth muscle cells (SMCs) cultured with high glucose was attributable to an increase in protein kinase C (PKC)-beta and NADPH oxidase expressions and accompanied by attenuation of Akt phosphorylation and augmentation of atrogin-1 expression. Treatment with ruboxistaurin (a PKC beta inhibitor) or with GW501516 (a peroxisome proliferator activated receptor 8 activator) reduced atrogin-1 expression and restored BK channel-mediated coronary vasodilation in diabetic mice. Our results suggested that oxidative stress inhibited Akt signaling and facilitated the FOXO-3a/FBXO-dependent BK-beta(1) degradation in diabetic vessels. Suppression of the FOXO-3a/FBXO pathway prevented vascular BK-beta(1) degradation and protected coronary function in diabetes. Diabetes 61:1860-1868, 2012
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