Metabolomics reveals the perturbations in the metabolome of Caenorhabditis elegans exposed to titanium dioxide nanoparticles

Abstract

The increasing use of nanotechnology in our daily life can have many unintended effects and pose adverse impact on human health, environment and ecosystems. Wider application of engineered nanoparticles, especially TiO₂ nanoparticles (TiO₂ NP) necessitates the understanding of toxicity and mechanism of action. Metabolomics provides a unique opportunity to find out biomarkers of nanoparticles exposure, which leads to the identification of cellular pathways and their biological mechanisms. Gas chromatography mass spectrometry (GC–MS)-based metabolomics approach was used in the present study to understand the toxicity of sub-lethal concentrations (7.7 and 38.5 µg/ml) of TiO₂ NP (<25 nm) in well-known, soil nematode Caenorhabditis elegans (C. elegans). Multivariate pattern recognition analysis reflected the perturbations in the metabolism (amino acids, organic acids, sugars) of C. elegans on exposure to TiO₂ NP. The biological pathways affected due to the exposure of TiO₂ NP were identified, among them mainly affected pathways are tricarboxylic acid (TCA) cycle, arachidonic acid metabolism and glyoxalate dicarobxylate metabolism. The manifestation of differential metabolic profile in organism exposed to TiO₂ (NP or bulk particle) was witnessed as an effect on reproduction. The present study demonstrates that metabolomics can be employed as a tool to understand the potential toxicity of nanoparticles in terms of organism–environment interactions as well as in assessing the organism function at the molecular level.

• C. elegans
• GC-MS
• metabolomics
• nanoparticles toxicity
• TiO₂ nanoparticles

Acknowledgements

The authors are thankful to Dr K.C. Gupta, Ex-Director, CSIR-IITR and Dr. C.S. Nautiyal, Director, CSIR-IITR, for scientific discussions and providing the necessary infrastructural facilities to carry out this work. The authors are thankful to Dr. L.K.S. Chauhan and Dr. P.N. Saxena, CSIR-IITR for TEM and SEM-EDAX studies of nanoparticles. Ch R and MS are thankful to Council of Scientific and Industrial Research, New Delhi for providing the research fellowship at CSIR-IITR.

Declaration of interest

The authors declare no competing financial interest.

This work was funded by CSIR, New Delhi, through NanoSHE (BSC 0112 network programme) to AS and MKRM and SERB, New Delhi through a fast-track young scientist scheme to MKRM.

Supplementary material available online

Supplementary Figures S1-S5 and Table S1