Xiang Fangfang, Cao Xuesen, Shen Bo, Chen Xiaohong, Guo Man, Ding Xiaoqiang, Zou Jianzhou
Department of Nephrology, Zhongshan Hospital, Fudan University, Shanghai, China.
Shanghai Key Laboratory of Kidney and Blood Purification, Shanghai, China.
Front Med (Lausanne). 2020 May 6;7:178. doi: 10.3389/fmed.2020.00178. eCollection 2020.
Chronic inflammation and immune system dysfunction have been evaluated as major factors in the pathogenesis of chronic kidney disease (CKD), contributing to the high mortality rates observed in these populations. Uremic toxins seem to be the potential "missing link." Indoxyl sulfate (IS) is one of the protein-bound renal toxins. It participates in multiple pathologies of CKD complications, yet its effect on immune cell has not been studied. This study aimed to explore the genome-wide expression profile in human peripheral blood T cells under stimulation by IS. In this study, we employed RNA-sequencing transcriptome profiling to identify differentially expressed genes (DEGs) responding to IS stimulation in human peripheral T cells . Flow cytometry and western blot were used to verify the discovery in RNA-sequencing analysis. Our results yielded a total of 5129 DEGs that were at least twofold up-regulated or down-regulated significantly by IS stimulation and half of them were concentration-specific. Analysis of T cell functional markers revealed a quite different transcription profile under various IS concentration. Transcription factors analysis showed the similar pattern. Aryl hydrocarbon receptor (AhR) target genes CYP1A1, CYP1B1, NQO1, and AhRR were up-regulated by IS stimulation. Pro-inflammatory genes TNF-α and IFN-γ were up-regulated as verified by flow cytometry analysis. DNA damage was induced by IS stimulation as confirmed by elevated protein level of p-ATM, p-ATR, p-BRCA1, and p-p53 in T cells. The toxicity of IS to T cells could be an important source of chronic inflammation in CKD patients. As an endogenous ligand of AhR, IS may influence multiple biological functions of T cells including inflammatory response and cell cycle regulation. Further researches are required to promulgate the underling mechanism and explore effective method of reserving T cell function in CKD.
慢性炎症和免疫系统功能障碍已被视为慢性肾脏病（CKD）发病机制中的主要因素，这导致了这些人群的高死亡率。尿毒症毒素似乎是潜在的“缺失环节”。硫酸吲哚酚（IS）是一种与蛋白质结合的肾脏毒素。它参与CKD并发症的多种病理过程，但其对免疫细胞的影响尚未得到研究。本研究旨在探讨IS刺激下人外周血T细胞的全基因组表达谱。在本研究中，我们采用RNA测序转录组分析来鉴定人外周T细胞中对IS刺激有反应的差异表达基因（DEG）。流式细胞术和蛋白质印迹法用于验证RNA测序分析中的发现。我们的结果共产生了5129个DEG，它们在IS刺激下至少有两倍的显著上调或下调，其中一半是浓度特异性的。T细胞功能标志物分析显示在不同IS浓度下转录谱有很大差异。转录因子分析显示了类似的模式。芳烃受体（AhR）靶基因CYP1A1、CYP1B1、NQO1和AhRR在IS刺激下上调。促炎基因TNF-α和IFN-γ经流式细胞术分析验证上调。T细胞中p-ATM、p-ATR、p-BRCA1和p-p53蛋白水平升高证实IS刺激诱导了DNA损伤。IS对T细胞的毒性可能是CKD患者慢性炎症的重要来源。作为AhR的内源性配体，IS可能影响T细胞的多种生物学功能，包括炎症反应和细胞周期调控。需要进一步研究以揭示潜在机制并探索在CKD中保留T细胞功能的有效方法。
