Uremic Toxin Indoxyl Sulfate Impairs Hydrogen Sulfide Formation in Renal Tubular Cells

Chien Lin Lu, Chun Hou Liao, Wen Bin Wu, Cai Mei Zheng, Kuo Cheng Lu, Ming Chieh Ma

研究成果: 雜誌貢獻文章同行評審

摘要

Hydrogen sulfide (H2S) was the third gasotransmitter to be recognized as a cytoprotectant. A recent study demonstrated that exogenous supplementation of H2S ameliorates functional insufficiency in chronic kidney disease (CKD). However, how the H2S system is impaired by CKD has not been elucidated. The uremic toxin indoxyl sulfate (IS) is known to accumulate in CKD patients and harm the renal tubular cells. This study therefore treated the proximal tubular cells, LLC-PK1, with IS to see how IS affects H2S formation. Our results showed that H2S release from LLC-PK1 cells was markedly attenuated by IS when compared with control cells. The H2S donors NaHS and GYY-4137 significantly attenuated IS-induced tubular damage, indicating that IS impairs H2S formation. Interestingly, IS downregulated the H2S-producing enzymes cystathionine β-synthase (CBS), cysta-thionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MST), and these effects could be reversed by inhibition of the IS receptor, aryl hydrocarbon receptor (AhR). As transcription factor specificity protein 1 (Sp1) regulates the gene expression of H2S-producing enzymes, we further showed that IS significantly decreased the DNA binding activity of Sp1 but not its protein expres-sion. Blockade of AhR reversed low Sp1 activity caused by IS. Moreover, exogenous H2S supple-mentation attenuated IS-mediated superoxide formation and depletion of the cellular glutathione content. These results clearly indicate that IS activates AhR, which then attenuates Sp1 function through the regulation of H2S-producing enzyme expression. The attenuation of H2S formation contributes to the low antioxidant defense of glutathione in uremic toxin-mediated oxidative stress, causing tubular cell damage.
原文英語
文章編號361
期刊Antioxidants
11
發行號2
DOIs
出版狀態已發佈 - 2月 2022

ASJC Scopus subject areas

  • 生物化學
  • 生理學
  • 分子生物學
  • 臨床生物化學
  • 細胞生物學

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