Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey, United States of America.
PLoS One. 2011 Jan 21;6(1):e14568. doi: 10.1371/journal.pone.0014568.
Osteopontin (OPN) is a pleiotropic protein implicated in various inflammatory responses including ischemia-reperfusion (I-R) injury. Two distinct forms of the protein have been identified: an extensively studied secreted form (sOPN) and a less-well-known intracellular form (iOPN). Studies have shown that increased OPN expression parallels the time course of macrophage infiltration into injured tissue, a late event in the development of cerebral infarcts. sOPN has been suggested to promote remodeling of the extracellular matrix in the brain; the function of iOPN may be to facilitate certain signal transduction processes. Here, we studied OPN expression in adult male Sprague-Dawley rats subjected to global forebrain I-R injury. We found iOPN in the cytoplasm of both cortices and the hippocampus, but unexpectedly only the right cortex exhibited a marked increase in the iOPN level after 45 min of reperfusion. Acetaminophen, a drug recently shown to decrease apoptotic incidence, caspase-9 activation, and mitochondrial dysfunction during global I-R, significantly inhibited the increase in iOPN protein in the right cortex, suggesting a role for iOPN in the response to I-R injury in the right cortex.
骨桥蛋白 (OPN) 是一种多功能蛋白，参与多种炎症反应，包括缺血再灌注 (I-R) 损伤。该蛋白有两种不同的形式：一种是广泛研究的分泌型（sOPN），另一种是不太知名的胞内型（iOPN）。研究表明，OPN 表达的增加与巨噬细胞浸润损伤组织的时间进程相平行，这是脑梗死发展的晚期事件。sOPN 被认为可促进大脑细胞外基质的重塑；iOPN 的功能可能是促进某些信号转导过程。在这里，我们研究了成年雄性 Sprague-Dawley 大鼠在全脑 I-R 损伤后 OPN 的表达。我们发现，iOPN 存在于皮质和海马体的细胞质中，但令人意外的是，只有右侧皮质在再灌注 45 分钟后 iOPN 水平显著增加。醋氨酚是一种最近被发现可在全脑 I-R 期间降低细胞凋亡发生率、半胱天冬酶-9 激活和线粒体功能障碍的药物，它显著抑制了右侧皮质中 iOPN 蛋白的增加，这表明 iOPN 在右侧皮质对 I-R 损伤的反应中起作用。
