Pyo Min Cheol, Choi In-Geol, Lee Kwang-Won
Department of Biotechnology, College of Life Science & Biotechnology, Korea University, Seoul 02841, Korea.
Toxins (Basel). 2021 Mar 6;13(3):190. doi: 10.3390/toxins13030190.
Ochratoxin A (OTA) is a mycotoxin occurring in foods consumed by humans. Recently, there has been growing global concern regarding OTA toxicity. The main target organ of OTA is the kidney, but the mechanism underlying renal toxicity is not well known. In this study, human-derived proximal tubular epithelial cells, HK-2 cells, were used for RNA-sequencing (RNA-seq) and transcriptome analysis. In total, 3193 differentially expressed genes were identified upon treatment with 200 nM OTA in HK-2 cells; of these, 2224 were upregulated and 969 were downregulated. Transcriptome analysis revealed that OTA significantly affects hypoxia, epithelial-mesenchymal transition (EMT), apoptosis, and xenobiotic metabolism pathways in kidney cells. Quantitative real-time PCR analysis showed gene expression patterns similar to RNA-seq analysis. Expression of EMT markers (E-cadherin and fibronectin), apoptosis markers (caspase-3 and Bax), and kidney injury molecule-1 (KIM-1) was suppressed by inhibiting AhR expression using siRNA, and the related transcription factors, Smad2/3, and HIF-1α were downregulated. Smad2/3 suppression with siRNA could inhibit fibronetcin, caspase-3, Bax, and KIM-1 expression. Fibronetcin, caspase-3, Bax, and KIM-1 expression could be increased with HIF-1α suppression with siRNA. Taken together, these findings suggest that OTA-mediated kidney toxicity via the AhR-Smad2/3-HIF-1α signaling pathways leads to induction of EMT, apoptosis, and kidney injury.
赭曲霉毒素A（OTA）是一种存在于人类食用食物中的霉菌毒素。最近，全球对OTA毒性的关注日益增加。OTA的主要靶器官是肾脏，但其肾毒性的潜在机制尚不清楚。在本研究中，使用人源近端肾小管上皮细胞HK-2细胞进行RNA测序（RNA-seq）和转录组分析。在用200 nM OTA处理HK-2细胞后，共鉴定出3193个差异表达基因；其中，2224个上调，969个下调。转录组分析表明，OTA显著影响肾细胞中的缺氧、上皮-间质转化（EMT）、细胞凋亡和外源性物质代谢途径。定量实时PCR分析显示基因表达模式与RNA-seq分析相似。使用siRNA抑制芳烃受体（AhR）表达可抑制EMT标志物（E-钙黏蛋白和纤连蛋白）、细胞凋亡标志物（半胱天冬酶-3和Bax）以及肾损伤分子-1（KIM-1）的表达，相关转录因子Smad2/3和缺氧诱导因子-1α（HIF-1α）下调。用siRNA抑制Smad2/3可抑制纤连蛋白、半胱天冬酶-3、Bax和KIM-1的表达。用siRNA抑制HIF-1α可增加纤连蛋白、半胱天冬酶-3、Bax和KIM-1的表达。综上所述，这些发现表明OTA通过AhR-Smad2/3-HIF-1α信号通路介导的肾毒性导致EMT、细胞凋亡和肾损伤的诱导。
