Division of Renal Diseases and Hypertension, University of Colorado at Denver and Health Sciences Center, Aurora, 80262, USA.
Am J Physiol Renal Physiol. 2011 May;300(5):F1235-43. doi: 10.1152/ajprenal.00348.2010. Epub 2011 Jan 26.
Cyst expansion in polycystic kidney disease (PKD) results in localized hypoxia in the kidney that may activate hypoxia-inducible factor-1α (HIF-1α). HIF-1α and autophagy, a form of programmed cell repair, are induced by hypoxia. The purposes were to determine HIF-1α expression and autophagy in rat and mouse models of PKD. HIF-1α was detected by electrochemiluminescence. Autophagy was visualized by electron microscopy (EM). LC3 and beclin-1, markers of autophagy, were detected by immunoblotting. Eight-week-old male heterozygous (Cy/+) and 4-wk-old homozygous (Cy/Cy) Han:SPRD rats, 4-wk-old cpk mice, and 112-day-old Pkd2WS25/- mice with a mutation in the Pkd2 gene were studied. HIF-1α was significantly increased in massive Cy/Cy and cpk kidneys and not smaller Cy/+ and Pkd2WS25/- kidneys. On EM, features of autophagy were seen in wild-type (+/+), Cy/+, and cpk kidneys: autophagosomes, mitophagy, and autolysosomes. Specifically, autophagosomes were found on EM in the tubular cells lining the cysts in cpk mice. The increase in LC3-II, a marker of autophagosome production and beclin, a regulator of autophagy, in Cy/Cy and cpk kidneys, followed the same pattern of increase as HIF-1α. To determine the role of HIF-1α in cyst formation and/or growth, Cy/+ rats, Cy/Cy rats, and cpk mice were treated with the HIF-1α inhibitor 2-methoxyestradiol (2ME2). 2ME2 had no significant effect on kidney volume or cyst volume density. In summary, HIF-1α is highly expressed in the late stages of PKD and is associated with an increase in LC3-II and beclin-1. The first demonstration of autophagosomes in PKD kidneys is reported. Inhibition of HIF-1α did not have a therapeutic effect.
多囊肾病 (PKD) 中的囊肿扩张导致肾脏局部缺氧，这可能激活缺氧诱导因子-1α (HIF-1α)。缺氧会诱导 HIF-1α 和自噬，这是一种程序性细胞修复形式。本研究旨在确定 PKD 大鼠和小鼠模型中的 HIF-1α 表达和自噬。通过电化学发光检测 HIF-1α，通过电子显微镜 (EM) 观察自噬，通过免疫印迹检测自噬标志物 LC3 和 beclin-1。研究了 8 周龄雄性杂合子（Cy/+）和 4 周龄纯合子（Cy/Cy）Han:SPRD 大鼠、4 周龄 cpk 小鼠以及 112 天大的 Pkd2WS25/- 突变小鼠。在大量的 Cy/Cy 和 cpk 肾脏中，HIF-1α 显著增加，而在较小的 Cy/+和 Pkd2WS25/-肾脏中则没有增加。在野生型（+/+）、Cy/+和 cpk 肾脏的 EM 中观察到自噬的特征：自噬体、线粒体自噬和自噬溶酶体。特别是，在 cpk 小鼠的囊肿衬里的管状细胞中发现了自噬体。Cy/Cy 和 cpk 肾脏中 LC3-II（自噬体产生的标志物）和 beclin（自噬的调节剂）的增加与 HIF-1α 的增加模式相同。为了确定 HIF-1α 在囊肿形成和/或生长中的作用，用 HIF-1α 抑制剂 2-甲氧基雌二醇 (2ME2) 处理 Cy/+大鼠、Cy/Cy 大鼠和 cpk 小鼠。2ME2 对肾脏体积或囊肿体积密度没有显著影响。总之，HIF-1α 在 PKD 的晚期高度表达，与 LC3-II 和 beclin-1 的增加相关。首次报道了 PKD 肾脏中自噬体的存在。抑制 HIF-1α 没有治疗效果。
