Related Experiment Video
Updated: Jun 15, 2026
Natural Product Discovery with LC-MS/MS Diagnostic Fragmentation Filtering: Application for Microcystin Analysis
Published on: May 31, 2019
Mitochondrial toxicity of microcystin-LR on cultured cells: application to the analysis of contaminated water samples
Grzegorz Jasionek1, Alexander Zhdanov, John Davenport
1Biochemistry Department, University College Cork, College Road, Cork, Ireland.
Abstract:
Microcystins (MC) are potent hepatic toxins delivered into the cells by organic anion transporting peptides (OATP) where they target protein phosphatases and mitochondria. We analyzed the effects of MC-LR on primary hepatocytes, HepG2, and Jurkat T cells, and isolated rat liver mitochondria by measuring changes in O(2) consumption by optical oxygen sensing technique. Respiration of fresh primary hepatocytes was inhibited by MC-LR with EC50 = 2.74 +/- 0.65 nM, whereas an uncoupling effect on mitochondrial state 2 and state 3 respiration was observed with glutamate/malate as a substrate. HepG2 and Jurkat T cells lacking OATP showed no sensitivity to MC-LR; however, facilitated delivery of MC-LR resulted in a marked enhancement of HepG2 O(2) consumption and inhibition of Jurkat O(2) consumption at >or=0.1 nM. The respiratory response did not coincide with changes in viability, total cellular ATP, extracellular acidification, ROS formation, or protein phosphorylation, which were detectable at higher MC-LR doses. Such prominent effect on cellular respiration was therefore used for the detection of MC-LR in environmental samples. A simple and sensitive screening assay for MC-LR toxicity was developed, which uses Jurkat cells, facilitated delivery of the toxin(s) and measurement on a fluorescent reader. The assay was applied to a panel of environmental samples suspected to contain MC and benchmarked against the ELISA test. It allowed identification of toxic samples and quantification of both nonspecific and MC-LR type of toxicity.
Insights
Microcystin-LR (MC-LR) toxins disrupt cellular respiration, particularly in cells with organic anion transporting peptides (OATP). A new assay using Jurkat cells detects MC-LR toxicity in environmental samples.
Area of Science:
- Environmental toxicology
- Cellular respiration
- Biochemical assays
Background:
- Microcystins (MC) are potent toxins targeting liver cells via OATP transporters.
- MC-LR affects mitochondrial function and protein phosphatases.
- Cellular respiration is a sensitive indicator of MC-LR toxicity.
Purpose of the Study:
- To analyze the effects of MC-LR on cellular respiration in different cell types.
- To develop a sensitive screening assay for MC-LR detection in environmental samples.
- To compare the developed assay with ELISA for MC detection.
Main Methods:
- Measuring O(2) consumption in primary hepatocytes, HepG2, and Jurkat T cells using optical oxygen sensing.
- Analyzing mitochondrial respiration with glutamate/malate substrate.
- Developing a fluorescence-based assay using Jurkat cells for MC-LR detection.
- Benchmarking the assay against ELISA for environmental sample analysis.
Main Results:
- MC-LR inhibited primary hepatocyte respiration (EC50 = 2.74 nM) and caused uncoupling in isolated mitochondria.
- HepG2 and Jurkat T cells lacking OATP were insensitive, but facilitated MC-LR delivery altered O(2) consumption.
- The respiratory response was independent of viability, ATP, or ROS at lower MC-LR doses.
- The developed assay identified toxic samples and quantified MC-LR toxicity in environmental samples.
Conclusions:
- Cellular respiration is a sensitive biomarker for MC-LR toxicity.
- A novel, sensitive assay for MC-LR detection in environmental samples was successfully developed.
- The assay provides a valuable tool for monitoring microcystin contamination.
