Microcystin-LR-regulated transcriptome dynamics in ZFL cells

Aquat Toxicol. 2019 Jul;212:222-232. doi: 10.1016/j.aquatox.2019.04.018. Epub 2019 May 25.

Abstract

Microcystin-LR (MC-LR) is a highly toxic hepatotoxin that poses great hazards to aquatic organisms and even human health. The zebrafish liver cell line (ZFL) is a valuable model for investigating toxicity and metabolism of toxicants. However, the toxicity of MC-LR and its effects on gene transcription of ZFL cells remains to be characterized. In this study, we determined the toxicity of MC-LR for ZFL cells and investigated the effects of MC-LR on cellular transcriptome dynamics. The EC50 of MC-LR for ZFL cells was 80.123 μg/mL. The ZFL cells were exposed to 10 μg/mL MC-LR for 0, 1, 3, 6, 12 or 24 h, and RNA-sequencing was performed to analyze gene transcription. A total of 10,209 genes were found to be regulated by MC-LR. The numbers of up- and down-regulated genes at different time points ranged from 2179 to 3202 and from 1501 to 2597, respectively. Furthermore, 1543 genes underwent differential splicing (AS) upon MC-LR exposure, of which 620 were not identified as differentially expressed gene (DEG). The effects of MC-LR on cellular functions were highly time-dependent. MAPK (mitogen-activated protein kinase) and FoxO (forkhead box O) signaling pathways were the most prominent pathways activated by MC-LR. Steroid biosynthesis and terpenoid backbone biosynthesis were the most enriched for the down-regulated genes. A gene regulatory network was constructed from the expression profile datasets and the candidate master transcription factors were identified. Our results shed light on the molecular mechanisms of MC-LR cellular toxicity and the transcriptome landscapes of ZFL cells upon MC-LR toxicity.

Keywords: Gene transcription; Microcystin; Signaling pathway; Transcriptome; ZFL cell line.

MeSH terms

  • Animals
  • Cell Line
  • Down-Regulation / drug effects
  • Hepatocytes / drug effects
  • Humans
  • Inhibitory Concentration 50
  • Liver / cytology
  • Liver / drug effects
  • Marine Toxins
  • Microcystins / toxicity*
  • Mitogen-Activated Protein Kinases / metabolism
  • Signal Transduction / drug effects*
  • Transcriptome / drug effects*
  • Water Pollutants, Chemical / toxicity
  • Zebrafish / physiology

Substances

  • Marine Toxins
  • Microcystins
  • Water Pollutants, Chemical
  • Mitogen-Activated Protein Kinases
  • cyanoginosin LR