Pediatric Nephrology Fellowship Program, Nationwide Children's Hospital, The Ohio State University, Columbus, Ohio, USA.
Kidney Int. 2011 Jul;80(2):174-80. doi: 10.1038/ki.2011.109. Epub 2011 Apr 27.
Although the urinary tract is constantly challenged by microbial invasion, it remains free from colonization. Although little is known about how the urinary tract maintains sterility, the presence of antimicrobial peptides (AMPs) in the urine suggests that they may play a role in its protection from infection. Ribonuclease 7 (RNase 7) is a potent AMP that was first identified in the skin. Here, we characterize the expression and relevance of RNase 7 in the human kidney and urinary tract. Using RNA isolated from healthy human tissue, we performed quantitative real-time PCR and found basal RNASE7 expression in kidney and bladder tissue. Immunohistochemical and immunofluorescent analysis localized RNase 7 to the urothelium of the bladder, ureter, and the intercalated cells of the collecting tubules. In control urine samples from healthy individuals, the concentration of RNase 7 was found to be in the low micromolar range; very abundant for an AMP. Antibacterial neutralization assays showed that urinary RNase 7 has potent antimicrobial properties against Gram-negative and Gram-positive uropathogenic bacteria. Thus, RNase 7 is expressed in the human kidney and urinary tract and it may have an important antimicrobial role in maintaining tract sterility.
尽管尿路不断受到微生物入侵的挑战，但它仍然保持无菌状态。尽管人们对尿路如何保持无菌状态知之甚少，但尿液中存在抗菌肽（AMPs）表明它们可能在保护尿路免受感染方面发挥作用。核糖核酸酶 7（RNase 7）是一种在皮肤中首次被发现的强效 AMP。在这里，我们描述了 RNase 7 在人肾脏和泌尿道中的表达和相关性。使用从健康人组织中分离的 RNA，我们进行了定量实时 PCR，发现肾脏和膀胱组织中存在基础 RNASE7 表达。免疫组织化学和免疫荧光分析将 RNase 7 定位于膀胱、输尿管的尿路上皮和集合管的闰细胞。在来自健康个体的对照尿样中，发现 RNase 7 的浓度处于低微摩尔范围内；对于 AMP 来说非常丰富。抗菌中和测定表明，尿 RNase 7 对革兰氏阴性和革兰氏阳性尿路致病菌具有强大的抗菌特性。因此，RNase 7 在人肾脏和泌尿道中表达，它可能在维持泌尿道无菌状态方面具有重要的抗菌作用。
