High throughput metabolomic studies of developmental toxicity in Japanese medaka

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1 High throughput metabolomic studies of developmental toxicity in Japanese medaka SETAC 4 th World Congress 18 th November 2004 Mark Viant University of Birmingham, UK & Jake Bundy, Chris Pincetich, Ron Tjeerdema University of California, Davis

2 Overview Rationale for study. Study 1: Metabolomics-based dose-response relationship. Study 2: Developmental metabolic trajectories including novel metabolomics methods. Conclusions and Future recommendation

Rationale for study Build omics methods upon existing Embryo Toxicity Assays with the goals to provide more sensitive and specific biological endpoints.

3 Rationale for study Build omics methods upon existing Embryo Toxicity Assays with the goals to provide more sensitive and specific biological endpoints. Develop tools for screening changes in functional molecular phenotype in response to developmental toxicants. Model organism: Japanese medaka Developmental toxicant: trichloroethylene (TCE)

4 Experimental design for Study 1 TCE dose-response Expose developing medaka embryos to five concentrations of TCE (N=4, 25 C). Preserve replicates of 100 eggs on day 7. Exposure period (TCE = 0,9,22,44,88,175 ppm) Day 1 Day 8 Metabolomics

5 Freeze groups of 100 eggs Overview of metabolomics approach Extract whole egg using: 1. acetonitrile:h 2 O 2. perchloric acid Measure metabolite profile by 1 H NMR spectroscopy Raw data Spectral processing and multivariate analysis

6 1 H NMR spectrum of medaka embryo extract Nucleotides, e.g. ATP Carbohydrates, e.g. ribosyl moiety Organic acids, e.g. succinate Amino acids, e.g. tyrosine chemical shift (ppm)

7 PCA scores plot TCE induced dose-dependent metabolic toxicity 1.0 PC 2 scores Control 9 mg/l 22 mg/l mg/l 88 mg/l 175 mg/l PC 1 scores

8 PCA loads plot Metabolic biomarker profile for TCE toxicity Lactate Glucose Hydrophobic amino acids TCE toxicity 0.0 ATP Phosphocreatine Glutamate controls Chemical shift (ppm) PC1 - PC2 loadings

9 Comparison of dose response profiles for traditional and metabolomic endpoints % eggs dead or failed to hatch Metabolomic response Failure to hatch Death PC1 PC2 score TCE concentration (log scale)

10 Experimental design for Study 2 Developmental metabolic trajectories Expose developing medaka embryos to two concentrations of TCE at which no developmental abnormalities were induced. Preserve replicates of 100 eggs on each day. Exposure period (TCE = 0, 800 ppb, 8 ppm) Day 1 Day 8 Metabolomics

11 NMR spectra of medaka Reduced peak congestion using 2-D NMR STANDARD 1-D 1 H NMR spectrum (7 min) NEW Projection of 2-D J-resolved spectrum (20 min) Viant, Biochem. Biophys. Res. Comm. 310, (2003).

12 NMR spectra of medaka Glog transformation to increase weighting of low concentration metabolites No transformation After glog transformation Purohit, Rocke, Viant, Woodruff, OMICS 8, (2004).

13 PCA scores plot Changes in metabolome during embryogenesis 8 6 Developmental metabolic trajectory 4 Day 5 Scores on PC 2 (10.16%) Day 3 Day 4 Day 6 Day 7-6 Day 2 Controls Day 8-8 Day Scores on PC 1 (75.18%)

14 PCA scores plot Effects of TCE on developmental trajectory Scores on PC 2 (10.16%) Day Controls 800 ppb TCE 8 ppm TCE Scores on PC 1 (75.18%)

15 PCA loads plot Metabolic biomarker profile 2-D NMR spectra yield a considerably simplified PCA loads plot, significantly aiding interpretation of metabolic changes. But what about peak assignments and mechanism?

16 Conclusions and Future recommendation Demonstrated unbiased metabolomics approach for characterizing toxicant-induced phenotypic changes. Approach is extremely reproducible, inexpensive and rapid. Identified need to improve peak quantification and identification. Applied 2-D NMR and Glog transformation to improve peak resolution. Propose to construct a community-based public database containing NMR spectra of pure metabolites.

17 Acknowledgements Medaka studies Chris Pincetich (UCD) Ron Tjeerdema (UCD) Jake Bundy (Cambridge) Bioinformatics David Rocke (UCD) David Woodruff (UCD) Parul Purohit (UCD) NMR Jeff de Ropp (UCD) Funding UK Natural Environment Research Council Funding USA UC Toxic Substances Research and Teaching Program

Characterizing Dispersant/Dispersed Oil Effects. Topics

Characterizing Dispersant/Dispersed Oil Effects Ronald S. Tjeerdema Department of Environmental Toxicology University of California, Davis Topics The Responder s Toolbox Conclusions Bioassays WAF vs CEWAF