PULMONARY ENDOTHELIAL TRANSPLASMA MEMBRANE ELECTRON TRANSPORT

肺内皮细胞质膜电子传输

• 批准号: 6118844
• 负责人: MARILYN P MERKER
• 金额: $ 0.13万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 2000-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6118844
• 关键词: bioengineering /biomedical engineering; biological products; biomedical resource; enzymes; respiratory system

The pulmonary endothelium carries out a variety of metabolic precesses that modulate the composition of venous blood before it enters the systemic arterial circulation. These include activation and inactivation of vasoactive substances and the oxidation and reduction of blood constituents. One mechanism by which the endothelium influences the redox status of blood constituents involves electron transport systems (reductases) within the pulmonary endothelial cell plasma membrane that transfer reducing equivalents from intracellular donors to extracellular electron acceptors. The hypothesis motivating the studies that are being carried out in the ESR Center is that trans-plasma membrane electron transport is involved in regeneration of antioxidant components of the blood and redox cycling of pulmonary toxins such as paraquat. One criterion for putative electron acceptors for the transplasma membrane electron transporters is that, after addition of the acceptor to a su spen sion of pulmonary endothelial cells, evidence of reduction of the acceptor can be found in the extracellular medium. Paraquat was chosen for our initial studies in collaboration with the ESR Center because ESR studies have previously been carried out using paraquat and endothelial cells. Paraquat was added to bovine pulmonary artery endothelial cells grown on microcarrier beads, and the mixture was incubated at 37 degrees. About 60 minutes after addition of paraquat and the free radical spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) to endothelial cells, the signal indicating the presence of a radical trapped by DMPO was observed in the cell supernatant. A substantially lower intensity signal was observed when the cells were incubated with DMPO alone, in the absence of paraquat. These data show that the paraquat was reduced to the paraquat radical by the cells and that the paraquat radical reacted with molecular oxygen. The resulting oxygen radical products were trapped by the DMPO, and the trapped radical was detected in the extracellular medium. Thus, these studies demonstrate the feasibility of using EPR to study the role of transplasma membrane electron transport in the redox cycling of paraquat by endothelial cells.

肺内皮细胞进行多种代谢活动 调节静脉血成分的过程 进入全身动脉循环。 这些包括激活 血管活性物质的失活以及氧化和 血液成分减少。 一种机制，通过该机制 内皮细胞影响血液成分的氧化还原状态包括 肺内的电子传输系统（还原酶） 转移还原当量的内皮细胞质膜 从细胞内供体到细胞外电子受体。 这 假设激发了正在进行的研究 ESR 中心是跨质膜电子传递 参与血液抗氧化成分的再生， 肺部毒素（如百草枯）的氧化还原循环。 一项标准 跨质膜电子的假定电子受体 转运蛋白是，在将受体添加到悬浮液中后 肺内皮细胞，受体减少的证据 可以在细胞外介质中找到。 我们选择百草枯作为 与 ESR 中心合作进行的初步研究，因为 ESR 此前曾使用百草枯和 内皮细胞。 将百草枯添加到牛肺动脉中 内皮细胞在微载体珠上生长，混合物 37度孵化。 添加百草枯后约60分钟 和自由基自旋陷阱 5,5-二甲基-1-吡咯啉-N-氧化物 (DMPO) 对于内皮细胞，信号表明自由基的存在 在细胞上清液中观察到被 DMPO 捕获。 实质上 当细胞与以下物质一起孵育时，观察到较低强度的信号 单独使用 DMPO，不含百草枯。 这些数据表明 百草枯被细胞还原为百草枯自由基，并且 百草枯自由基与分子氧发生反应。 产生的氧气 自由基产物被 DMPO 捕获，捕获的自由基为 在细胞外介质中检测到。 因此，这些研究表明 利用EPR研究跨质膜作用的可行性 内皮细胞百草枯氧化还原循环中的电子传递 细胞。