Mishra Jaya, Ma Qing, Prada Anne, Mitsnefes Mark, Zahedi Kamyar, Yang Jun, Barasch Jonathan, Devarajan Prasad
Nephrology & Hypertension, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA.
J Am Soc Nephrol. 2003 Oct;14(10):2534-43. doi: 10.1097/01.asn.0000088027.54400.c6.
Acute renal failure (ARF) secondary to ischemic injury remains a common and potentially devastating problem. A transcriptome-wide interrogation strategy was used to identify renal genes that are induced very early after renal ischemia, whose protein products might serve as novel biomarkers for ARF. Seven genes that are upregulated >10-fold were identified, one of which (Cyr61) has recently been reported to be induced after renal ischemia. Unexpectedly, the induction of the other six transcripts was novel to the ARF field. In this study, one of these previously unrecognized genes was further characterized, namely neutrophil gelatinase-associated lipocalin (NGAL), because it is a small secreted polypeptide that is protease resistant and consequently might be readily detected in the urine. The marked upregulation of NGAL mRNA and protein levels in the early postischemic mouse kidney was confirmed. NGAL protein expression was detected predominantly in proliferating cell nuclear antigen-positive proximal tubule cells, in a punctate cytoplasmic distribution that co-localized with markers of late endosomes. NGAL was easily detected in the urine in the very first urine output after ischemia in both mouse and rat models of ARF. The appearance of NGAL in the urine was related to the dose and duration of renal ischemia and preceded the appearance of other urinary markers such as N-acetyl-beta-D-glucosaminidase and beta2-microglobulin. The origin of NGAL from tubule cells was confirmed in cultured human proximal tubule cells subjected to in vitro ischemic injury, where NGAL mRNA was rapidly induced in the cells and NGAL protein was readily detectable in the culture medium within 1 h of mild ATP depletion. NGAL was also easily detectable in the urine of mice with cisplatin-induced nephrotoxicity, again preceding the appearance of N-acetyl-beta-D-glucosaminidase and beta2-microglobulin. The results indicate that NGAL may represent an early, sensitive, noninvasive urinary biomarker for ischemic and nephrotoxic renal injury.
缺血性损伤继发的急性肾衰竭（ARF）仍然是一个常见且可能具有毁灭性的问题。我们采用了一种全转录组 interrogation 策略来鉴定肾缺血后早期被诱导的肾基因，其蛋白质产物可能作为 ARF 的新型生物标志物。我们鉴定出了 7 个上调超过 10 倍的基因，其中一个（Cyr61）最近已被报道在肾缺血后被诱导。出乎意料的是，其他 6 个转录本的诱导在 ARF 领域是新发现的。在本研究中，对这些先前未被识别的基因之一进行了进一步表征，即中性粒细胞明胶酶相关脂质运载蛋白（NGAL），因为它是一种小的分泌型多肽，具有蛋白酶抗性，因此可能很容易在尿液中检测到。我们证实了缺血后早期小鼠肾脏中 NGAL mRNA 和蛋白质水平的显著上调。NGAL 蛋白表达主要在增殖细胞核抗原阳性的近端小管细胞中检测到，呈点状细胞质分布，与晚期内体标记物共定位。在 ARF 的小鼠和大鼠模型中，缺血后首次排尿时尿液中很容易检测到 NGAL。尿液中 NGAL 的出现与肾缺血的剂量和持续时间有关，并且在其他尿液标志物如 N - 乙酰 - β - D - 氨基葡萄糖苷酶和β2 - 微球蛋白出现之前。在体外缺血损伤的培养人近端小管细胞中证实了 NGAL 来自小管细胞，在轻度 ATP 耗竭 1 小时内，细胞中 NGAL mRNA 迅速诱导，培养基中很容易检测到 NGAL 蛋白。在顺铂诱导的肾毒性小鼠的尿液中也很容易检测到 NGAL，同样在 N - 乙酰 - β - D - 氨基葡萄糖苷酶和β2 - 微球蛋白出现之前。结果表明，NGAL 可能代表缺血性和肾毒性肾损伤的一种早期、敏感、非侵入性的尿液生物标志物。
