Yoder Bradley K, Hou Xiaoying, Guay-Woodford Lisa M
Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0024, USA.
J Am Soc Nephrol. 2002 Oct;13(10):2508-16. doi: 10.1097/01.asn.0000029587.47950.25.
Recent evidence has suggested an association between structural and/or functional defects in the primary apical cilium of vertebrate epithelia and polycystic kidney disease (PKD). In Caenorhabditis elegans, the protein orthologues of the PKD-related proteins, polycystin-1 (LOV-1), polycystin-2 (PKD2), and polaris (OSM-5), co-localize in the cilia of male-specific sensory neurons, and defects in these proteins cause abnormalities of cilia structure and/or function. This study sought to determine whether the mammalian polycystins are expressed in primary cilia of renal epithelia and whether these proteins co-localize with polaris and cystin, the newly described, cilia-associated protein that is disrupted in the cpk mouse. To begin to address this issue, the expression of the protein products encoded by the PKD1, PKD2, Tg737, and cpk genes were examined in mouse cortical collecting duct (mCCD) cells using an immunofluorescence-based approach with a series of previously well-characterized antibodies. The mCCD cells were grown on cell culture inserts to optimize cell polarization and cilia formation. The data demonstrate co-localization in cilia of polycystin-1 and polycystin-2, which are the principal proteins involved in autosomal dominant polycystic kidney disease, with polaris and cystin, which are proteins that are disrupted in the Tg737(orpk)and cpk mouse models of autosomal recessive polycystic kidney disease, respectively. These data add to a growing body of evidence that suggests that primary cilium plays a key role in normal physiologic functions of renal epithelia and that defects in ciliary function contribute to the pathogenesis of PKD.
最近有证据表明，脊椎动物上皮细胞的初级纤毛的结构和/或功能缺陷与多囊肾病（PKD）之间存在关联。在秀丽隐杆线虫中，与PKD相关的蛋白质的直系同源蛋白，多囊蛋白-1（LOV-1）、多囊蛋白-2（PKD2）和极地蛋白（OSM-5），共同定位于雄性特异性感觉神经元的纤毛中，这些蛋白质的缺陷会导致纤毛结构和/或功能异常。本研究旨在确定哺乳动物多囊蛋白是否在肾上皮细胞的初级纤毛中表达，以及这些蛋白质是否与极地蛋白和胱氨酸共定位，胱氨酸是一种新描述的与纤毛相关的蛋白质，在cpk小鼠中被破坏。为了开始解决这个问题，使用基于免疫荧光的方法和一系列先前已充分表征的抗体，在小鼠皮质集合管（mCCD）细胞中检测了由PKD1、PKD2、Tg737和cpk基因编码的蛋白质产物的表达。mCCD细胞生长在细胞培养插入物上，以优化细胞极化和纤毛形成。数据表明，参与常染色体显性多囊肾病的主要蛋白质多囊蛋白-1和多囊蛋白-2，与分别在常染色体隐性多囊肾病的Tg737（orpk）和cpk小鼠模型中被破坏的蛋白质极地蛋白和胱氨酸，在纤毛中共定位。这些数据进一步证明了越来越多的证据表明，初级纤毛在肾上皮细胞的正常生理功能中起关键作用，并且纤毛功能缺陷有助于PKD的发病机制。
