Urine Podocyte mRNAs Mark Progression of Renal Disease
Urine Podocyte mRNAs Mark Progression of Renal Disease
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DOI：
10.1681/asn.2007121328
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发表时间：
2009-05-01
影响因子：
13.6
通讯作者：
Wiggins, Roger C.
中科院分区：
文献类型：
--
作者：
Sato, Yuji;Wharram, Bryan L.;Wiggins, Roger C.
由于足细胞的丢失与肾小球硬化有关，因此通过测量尿液中的足细胞产物来监测足细胞的丢失可能在临床上有用。为了确定单次足细胞损伤是否会导致持续性足细胞损失，我们使用白喉毒素受体（hDTR）转基因大鼠诱导有限的足细胞耗竭。我们通过定量逆转录酶 PCR 检测尿液颗粒中的去氧肾上腺素和足细胞蛋白 mRNA 来监测足细胞损失。水通道蛋白 2 mRNA 用作肾脏参考基因，以解释肾脏对 RNA 数量和质量的不同贡献。我们发现，单次注射白喉毒素会导致蛋白尿和足细胞 mRNA（podocin 和 nephrin）出现初始峰值，8 天后出现第二个蛋白尿和足细胞 mRNA 峰值，podocin 阳性但 nephrin 阴性。持续数月的蛋白尿与尿液中 podocin 阳性、nephrin 阴性 mRNA 相关。尿液中持续存在足细胞 mRNA 的动物进展为终末期肾病 (ESRD)，伴有足细胞整体耗竭和间质疤痕。扩张小管中的足细胞表达足萼蛋白和足蛋白，但不表达去氧肾上腺素，这与具有改变表型的分离足细胞相一致。平行人体研究表明，经活检证实的肾小球损伤与尿液中 podocin：水通道蛋白 2 和去氧肾上腺素：水通道蛋白 2 摩尔比增加相关。我们的结论是，单次足细胞损伤可引发肾小球不稳定，导致足细胞持续丢失以及从尿液中回收的足细胞表型改变。尿液中的足细胞 mRNA 可能是诊断和监测肾小球疾病的有用临床工具。
Because loss of podocytes associates with glomerulosclerosis, monitoring podocyte loss by measuring podocyte products in urine may be clinically useful. To determine whether a single episode of podocyte injury would cause persistent podocyte loss, we induced limited podocyte depletion using a diphtheria toxin receptor (hDTR) transgenic rat. We monitored podocyte loss by detecting nephrin and podocin mRNA in urine particulates with quantitative reverse transcriptase-PCR. Aquaporin 2 mRNA served as a kidney reference gene to account for variable kidney contribution to RNA amount and quality. We found that a single injection of diphtheria toxin resulted in an initial peak of proteinuria and podocyte mRNAs (podocin and nephrin) followed 8 d later by a second peak of proteinuria and podocyte mRNAs that were podocin positive but nephrin negative. Proteinuria that persisted for months correlated with podocin-positive, nephrin-negative mRNAs in urine. Animals with persistent podocyte mRNA in urine progressed to ESRD with global podocyte depletion and interstitial scarring. Podocytes in ectatic tubules expressed podocalyxin and podocin proteins but not nephrin, compatible with detached podocytes' having an altered phenotype. Parallel human studies showed that biopsy-proven glomerular injury associated with increased urinary podocin:aquaporin 2 and nephrin:aquaporin 2 molar ratios. We conclude that a single episode of podocyte injury can trigger glomerular destabilization, resulting in persistent podocyte loss and an altered phenotype of podocytes recovered from urine. Podocyte mRNAs in urine may be a useful clinical tool for the diagnosis and monitoring of glomerular diseases.