Department of Internal Medicine II, University of Regensburg, Regensburg, Germany.
Nephron Physiol. 2010;116(1):p1-8. doi: 10.1159/000315658. Epub 2010 Jun 8.
Recent evidence obtained in rodents indicates that gap junctions in the juxtaglomerular apparatus play an important role in the control of renin-producing cells and in tubuloglomerular signaling. These gap junctions are formed by cell-specific expression patterns of the vascular connexins Cx37, Cx40, Cx43 and Cx45. In order to obtain a first indication if gap junctions might play a similar important functional role in the juxtaglomerular apparatus of human kidneys, this study aimed to characterize the juxtaglomerular localization of Cx40, Cx37, Cx43 and Cx45 in human kidney specimens. We found Cx37, Cx40 and Cx43, but not Cx45 expression in high density in the extraglomerular mesangium. Renin-producing cells displayed strong immunoreactivity for Cx40 and Cx37. Cx37, Cx40 and Cx43 were also seen in the endothelium of arteries/arterioles outside of the glomeruli, whereas Cx45 was located in vascular smooth muscle cells. All four connexins were also expressed within the glomeruli. These findings indicate that the expression pattern of vascular connexins in the human kidney cortex is very similar to that previously found for mouse and rat kidneys, suggesting that the intrarenal expression pattern of vascular connexins is conserved among the mammalian species. Because of this similarity, and in particular in view of the strong expression of Cx37 and Cx40 in the juxtaglomerular area, we infer that those functions of connexins that have already been demonstrated for rodent kidneys, such as a central role of Cx40 for the development and function of renin-producing cells and for tubuloglomerular signal transmission, might hold for human kidneys as well.
最近在啮齿动物中获得的证据表明，血管连接蛋白 Cx37、Cx40、Cx43 和 Cx45 的血管特异性表达模式在球旁器中形成的缝隙连接在控制肾素产生细胞和管球信号传递方面发挥着重要作用。为了初步确定缝隙连接是否在人类肾脏的球旁器中发挥类似的重要功能作用，本研究旨在研究血管连接蛋白 Cx40、Cx37、Cx43 和 Cx45 在人类肾脏标本中的球旁器定位。我们发现 Cx37、Cx40 和 Cx43 在肾小球外系膜中高度表达，但 Cx45 没有表达。肾素产生细胞对 Cx40 和 Cx37 表现出强烈的免疫反应性。Cx37、Cx40 和 Cx43 也见于肾小球外的动脉/小动脉内皮，而 Cx45 位于血管平滑肌细胞中。所有四种连接蛋白也在肾小球内表达。这些发现表明，血管连接蛋白在人类肾脏皮质中的表达模式与先前在小鼠和大鼠肾脏中发现的非常相似，这表明血管连接蛋白在哺乳动物中的肾内表达模式是保守的。由于这种相似性，特别是鉴于 Cx37 和 Cx40 在球旁器区域的强烈表达，我们推断，已经在啮齿动物肾脏中证明的连接蛋白的那些功能，如 Cx40 在肾素产生细胞的发育和功能以及管球信号传递中的核心作用，也可能适用于人类肾脏。
