Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
Am J Physiol Gastrointest Liver Physiol. 2011 Jul;301(1):G32-8. doi: 10.1152/ajpgi.00064.2011. Epub 2011 Apr 14.
Glutathione peroxidase-3 (Gpx3), the extracellular glutathione peroxidase synthesized largely in the kidney, binds to basement membranes of renal cortical epithelial cells. The present study assessed extrarenal expression of Gpx3 using RT-PCR and presence of Gpx3 protein using immunocytochemistry. Gpx3 expression was higher in kidney and epididymis than in other tissues. Gpx3 bound to basement membranes of epithelial cells in the gastrointestinal tract, the efferent ducts connecting the seminiferous tubules with the epididymis, the bronchi, and type II pneumocytes. It was not detected on the basement membrane of type I pneumocytes. Gpx3 was also present in the lumen of the epididymis. Transplantation of Gpx3(+/+) kidneys into Gpx3(-/-) mice led to Gpx3 binding to the same basement membranes to which it bound in Gpx3(+/+) mice but not to its presence in the epididymal lumen. These results show that Gpx3 from the blood binds to basement membranes of specific epithelial cells and indicate that the cells modify their basement membranes to cause the binding. They further indicate that at least two Gpx3 compartments exist in the organism. In one compartment, kidney supplies Gpx3 through the blood to specific basement membranes in a number of tissues. In the other compartment, the epididymis provides Gpx3 to its own lumen. Tissues other than kidney and epididymis express Gpx3 at lower levels and may supply Gpx3 to other compartments.
谷胱甘肽过氧化物酶 3（Gpx3）是一种主要在肾脏中合成的细胞外谷胱甘肽过氧化物酶，它与肾皮质上皮细胞的基底膜结合。本研究通过 RT-PCR 评估了 Gpx3 的肾脏外表达，并通过免疫细胞化学检测了 Gpx3 蛋白的存在。Gpx3 在肾脏和附睾中的表达高于其他组织。Gpx3 与胃肠道上皮细胞、连接精曲小管和附睾的输出小管、支气管和 II 型肺泡细胞的基底膜结合。在 I 型肺泡细胞的基底膜上未检测到 Gpx3。Gpx3 也存在于附睾管腔中。将 Gpx3(+/+)肾脏移植到 Gpx3(-/-)小鼠体内，导致 Gpx3 与 Gpx3(+/+)小鼠中相同的基底膜结合，但不与附睾管腔中的 Gpx3 结合。这些结果表明，血液中的 Gpx3 结合到特定上皮细胞的基底膜上，表明细胞修饰其基底膜以引起结合。它们进一步表明，至少存在两个 Gpx3 隔室在体内。在一个隔室中，肾脏通过血液将 Gpx3 供应到许多组织的特定基底膜上。在另一个隔室中，附睾将 Gpx3 供应到自己的管腔中。除肾脏和附睾外的组织以较低水平表达 Gpx3，并且可能将 Gpx3 供应到其他隔室。
