Aguirre Enara, Cadenas Susana
Department of Regenerative Cardiology, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Melchor Fernández Almagro 3, 28029 Madrid, Spain.
Biochim Biophys Acta. 2010 Oct;1797(10):1716-26. doi: 10.1016/j.bbabio.2010.06.009. Epub 2010 Jun 26.
The lipid peroxidation product 4-hydroxynonenal (HNE) increases the proton conductance of the inner mitochondrial membrane through effects on uncoupling proteins (UCPs) and the adenine nucleotide translocase (ANT); however, the relative contribution of the two carriers to these effects is unclear. To clarify this we isolated mitochondria from skeletal muscle and heart of wild-type and Ucp3 knockout (Ucp3KO) mice. To increase UCP3 expression, some mice were i.p. injected with LPS (12mg/kg body weight). In spite of the increased UCP3 expression levels, basal proton conductance did not change. HNE increased the proton conductance of skeletal muscle and heart mitochondria. In skeletal muscle, this increase was lower in Ucp3KO mice and higher in LPS-treated wild-type mice, and was partially abolished by GDP (UCPs inhibitor) and completely abolished by carboxyatractylate (ANT inhibitor) or addition of both inhibitors. GDP had no effect on HNE-induced conductance in heart mitochondria, but carboxyatractylate or administration of both inhibitors had a partial effect. GDP-mediated inhibition of HNE-activated proton conductance in skeletal muscle mitochondria was not observed in Ucp3KO mice, indicating that GDP is specific for UCP3, at least in muscle. Carboxyatractylate was able to inhibit UCP3, probably through an indirect mechanism. Our results are consistent with the conclusion that, in skeletal muscle, HNE-induced increase in proton conductance is mediated by UCP3 (30%) and ANT, whereas in the heart the increase is mediated by ANT and other carriers, possibly including UCP3.
脂质过氧化产物4-羟基壬烯醛（HNE）通过影响解偶联蛋白（UCPs）和腺嘌呤核苷酸转位酶（ANT）来增加线粒体内膜的质子传导；然而，这两种载体对这些效应的相对贡献尚不清楚。为了阐明这一点，我们从野生型和Ucp3基因敲除（Ucp3KO）小鼠的骨骼肌和心脏中分离出线粒体。为了增加UCP3的表达，一些小鼠腹腔注射脂多糖（12mg/kg体重）。尽管UCP3表达水平有所增加，但基础质子传导并未改变。HNE增加了骨骼肌和心脏线粒体的质子传导。在骨骼肌中，Ucp3KO小鼠的这种增加较低，而脂多糖处理的野生型小鼠的增加较高，并且被GDP（UCPs抑制剂）部分消除，被羧基苍术苷（ANT抑制剂）或同时添加两种抑制剂完全消除。GDP对心脏线粒体中HNE诱导的传导没有影响，但羧基苍术苷或同时使用两种抑制剂有部分作用。在Ucp3KO小鼠中未观察到GDP介导的对骨骼肌线粒体中HNE激活的质子传导的抑制作用，这表明GDP至少在肌肉中对UCP3具有特异性。羧基苍术苷能够抑制UCP3，可能是通过间接机制。我们的结果与以下结论一致：在骨骼肌中，HNE诱导的质子传导增加由UCP3（30%）和ANT介导，而在心脏中，增加由ANT和其他载体介导，可能包括UCP3。
