Activation of Disulfide Redox Switch in REDD1 Promotes Oxidative Stress Under Hyperglycemic Conditions.
Activation of Disulfide Redox Switch in REDD1 Promotes Oxidative Stress Under Hyperglycemic Conditions.
复制标题
作者：
在发育和DNA损伤反应1（REDD 1）中调节的应激反应蛋白与糖尿病患者的视觉缺陷有关。本文的目的是研究糖尿病患者视网膜REDD 1蛋白含量增加的机制。我们发现，在REDD 1 mRNA丰度或核糖体关联没有变化的情况下，链脲佐菌素诱导的糖尿病小鼠视网膜中REDD 1蛋白表达增加。口服抗氧化剂补充剂降低了糖尿病小鼠视网膜的氧化应激，抑制了REDD 1蛋白的表达。在人视网膜Müller细胞培养中，高血糖条件增加氧化应激，增强REDD 1表达，并独立于蛋白酶体抑制REDD 1降解。高血糖条件促进了REDD 1中C150/C157处的氧化还原敏感性交叉链二硫键，这是减少REDD 1降解所必需的。REDD 1结构的离散分子动力学模拟揭示了二硫键形成后降解决定子的变构调节，该二硫键破坏了REDD 1的溶酶体蛋白水解。K129处的REDD 1乙酰化是REDD 1被胞质伴侣HSC 70识别和被伴侣介导的自噬降解所必需的。在C150/C157二硫键形成时破坏REDD 1变构，可防止高血糖条件对REDD 1降解的抑制作用，并降低暴露于高血糖条件的细胞中的氧化应激。结果揭示了REDD 1的氧化还原调节，并证明了REDD 1二硫键开关在氧化应激发展中的作用。
The stress response protein regulated in development and DNA damage response 1 (REDD1) has been implicated in visual deficits in patients with diabetes. The aim here was to investigate the mechanism responsible for the increase in retinal REDD1 protein content that is observed with diabetes. We found that REDD1 protein expression was increased in the retina of streptozotocin-induced diabetic mice in the absence of a change in REDD1 mRNA abundance or ribosome association. Oral antioxidant supplementation reduced retinal oxidative stress and suppressed REDD1 protein expression in the retina of diabetic mice. In human retinal Müller cell cultures, hyperglycemic conditions increased oxidative stress, enhanced REDD1 expression, and inhibited REDD1 degradation independently of the proteasome. Hyperglycemic conditions promoted a redox-sensitive cross-strand disulfide bond in REDD1 at C150/C157 that was required for reduced REDD1 degradation. Discrete molecular dynamics simulations of REDD1 structure revealed allosteric regulation of a degron upon formation of the disulfide bond that disrupted lysosomal proteolysis of REDD1. REDD1 acetylation at K129 was required for REDD1 recognition by the cytosolic chaperone HSC70 and degradation by chaperone-mediated autophagy. Disruption of REDD1 allostery upon C150/C157 disulfide bond formation prevented the suppressive effect of hyperglycemic conditions on REDD1 degradation and reduced oxidative stress in cells exposed to hyperglycemic conditions. The results reveal redox regulation of REDD1 and demonstrate the role of a REDD1 disulfide switch in development of oxidative stress.