Department of Rheumatology and Immunology, Affiliated Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China.
Department of Clinical Laboratory, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu, China.
Front Immunol. 2023 Feb 9;14:1077645. doi: 10.3389/fimmu.2023.1077645. eCollection 2023.
Lupus nephritis (LN) is one of the most severe organ manifestations of systemic lupus erythematosus (SLE). Early identification of renal disease in SLE is important. Renal biopsy is currently recognized as the gold standard for diagnosing LN, however, it is invasive and inconvenient for dynamic monitoring. Urine has been considered more promising and valuable than blood in identifying inflamed kidney tissue. Here, we determine whether the signatures of tRNA-derived small noncoding RNA (tsRNA) in urinary exosomes can serve as novel biomarkers for the diagnosis of LN.
tsRNA sequencing was performed in exosome extracted from pooled urine of 20 LN patients and 20 SLE without LN, and the top 10 upregulated tsRNAs were screened as candidate markers of LN. The candidate urinary exosomal tsRNAs were primarily elected by TaqMan probe-based quantitative reverse transcription-PCR (RT-PCR) in 40 samples (20 LN and 20 SLE without LN) in the training phase. In the validation phase, selected tsRNAs from the training phase were further confirmed in a larger cohort (54 LN patients and 39 SLE without LN). Receiver operating characteristic curve (ROC) analysis was conducted to evaluate the diagnostic efficacy.
Upregulated levels of tRF3-Ile-AAT-1 and tiRNA5-Lys-CTT-1 in the urinary exosomes were observed in LN compared with SLE without LN ( < 0.0001 and < 0.001) and healthy controls ( < 0.01 and < 0.01), with the area under the curve (AUC) of 0.777 (95% CI: 0.681-0.874, sensitivity 79.63%, specificity 66.69%) and 0.715 (95% CI: 0.610-0.820, sensitivity 66.96%, specificity 76.92%) for discriminating LN from SLE without LN patients. SLE patients with mild activity and moderate to severe activity had higher levels of urinary exosome derived tRF3-Ile AAT-1 ( = 0.035 and < 0.001) and tiRNA5-Lys-CTT-1 ( = 0.021 and < 0.001) compared with patients with no activity. Moreover, bioinformatics analysis revealed that both of the tsRNAs regulate the immune process by modulating metabolism and signal pathway.
In this study, we demonstrated that urinary exosome tsRNAs can be served as noninvasive biomarkers for the efficient diagnosis and prediction of nephritis in SLE.
狼疮肾炎（LN）是系统性红斑狼疮（SLE）最严重的器官表现之一。早期识别 SLE 中的肾脏疾病很重要。肾活检目前被认为是诊断 LN 的金标准，但它具有侵入性且不方便进行动态监测。尿液在识别炎症性肾组织方面比血液更有前景和更有价值。在这里，我们确定尿外泌体中 tRNA 衍生的小非编码 RNA（tsRNA）的特征是否可以作为 LN 诊断的新型生物标志物。
对 20 例 LN 患者和 20 例无 LN 的 SLE 患者尿液中外泌体中的 tsRNA 进行测序，筛选出前 10 个上调的 tsRNA 作为 LN 的候选标志物。在训练阶段，通过 TaqMan 探针定量逆转录 PCR（RT-PCR）对 40 例样本（20 例 LN 和 20 例无 LN 的 SLE）中的候选尿外泌体 tsRNA 进行初步筛选。在验证阶段，在更大的队列（54 例 LN 患者和 39 例无 LN 的 SLE）中进一步证实了训练阶段中选定的 tsRNAs。进行接收者操作特征曲线（ROC）分析以评估诊断效果。
与无 LN 的 SLE 患者（<0.0001 和<0.001）和健康对照（<0.01 和<0.01）相比，LN 患者尿液外泌体中 tRF3-Ile-AAT-1 和 tiRNA5-Lys-CTT-1 的水平升高，曲线下面积（AUC）分别为 0.777（95%CI：0.681-0.874，敏感性 79.63%，特异性 66.69%）和 0.715（95%CI：0.610-0.820，敏感性 66.96%，特异性 76.92%），用于区分 LN 与无 LN 的 SLE 患者。轻度活动和中重度活动的 SLE 患者尿液外泌体衍生的 tRF3-Ile AAT-1（=0.035 和<0.001）和 tiRNA5-Lys-CTT-1（=0.021 和<0.001）水平较高与无活动的患者相比。此外，生物信息学分析表明，这两种 tsRNA 都通过调节代谢和信号通路来调节免疫过程。
在这项研究中，我们证明了尿外泌体 tsRNA 可以作为 SLE 肾炎有效诊断和预测的非侵入性生物标志物。
