Analysis of Sub-Lethal Toxicity of Perfluorooctane Sulfonate (PFOS) to Daphnia magna Using 1H Nuclear Magnetic Resonance-Based Metabolomics

Abstract

1H nuclear magnetic resonance (NMR)-based metabolomics was used to characterize the response of Daphnia magna after sub-lethal exposure to perfluorooctane sulfonate (PFOS), a commonly found environmental pollutant in freshwater ecosystems. Principal component analysis (PCA) scores plots showed significant separation in the exposed samples relative to the controls. Partial least squares (PLS) regression analysis revealed a strong linear correlation between the overall metabolic response and PFOS exposure concentration. More detailed analysis showed that the toxic mode of action is metabolite-specific with some metabolites exhibiting a non-monotonic response with higher PFOS exposure concentrations. Our study indicates that PFOS exposure disrupts various energy metabolism pathways and also enhances protein degradation. Overall, we identified several metabolites that are sensitive to PFOS exposure and may be used as bioindicators of D. magna health. In addition, this study also highlights the important utility of environmental metabolomic methods when attempting to elucidate acute and sub-lethal pollutant stressors on keystone organisms such as D. magna.

Perfluorinated Chemicals as Emerging Environmental Threats to Kidney Health

“…We identified ten studies (n=10) profiling numerous nascent metabolic changes related to PFAS exposure (71)(72)(73)(74)(75)(76)(77)(78)(79)(80). Animal studies demonstrated that PFAS exposure led to derangements in lipid metabolism (73,74,78,80), glucose and mitochondrial energy metabolism (71)(72)(73)(74)78,79), fatty acid metabolism and antioxidation (75,80), sex hormone homeostasis, and amino acid metabolism (71,72,76,(78)(79)(80). In the only human study, metabolomic profiling on 181 Chinese men demonstrated lipid and amino acid metabolism, xenobiotic detoxifying, and metabolic pathways directly linked to CKD pathogenesis, including glutathione metabolism and nitric oxide generation, were disrupted by PFAS exposure (77).…”

Focusing on “the important” through targeted NMR experiments: an example of selective13C–12C bond detection in complex mixtures

“…Daphnia are found in almost every fresh water body worldwide, and are the food source for many other aquatic species. 48,59,60 Therefore, the use of lipids is not only key to Daphnia survival, but also has many potential negative consequences to higher trophic levels (i.e. fish and higher predators) based on available food sources.…”

Investigation of Daphnia magna Sub-Lethal Exposure to Organophosphate Esters in the Presence of Dissolved Organic Matter Using 1H NMR-Based Metabolomics

“…Analysis of the 1 H NMR spectra was done in the proton chemical shift region of 0.5 to 10 ppm and the spectral region between 4.70 to 4.90 ppm was excluded due to the small residual H 2 O/HOD signals. The 1 H NMR spectra were divided into 0.02 ppm buckets giving 475 buckets in total and the integration mode was set to the sum of intensities with the spectra scaled to total intensity [ 45 , 46 , 47 ]. The 1 H NMR spectra were inputted into a PCA model.…”

“…The resulting PCA scores belonging to each treatment group were imported into Microsoft Excel (v. 14. Microsoft Corporation, Redmond, WA, USA) and were averaged per group and replotted with their associated standard errors to make the PCA scores plots [ 45 , 46 , 47 ]. The statistical significance ( p < 0.05) between the PCA score values of each treatment group were determined by a t -test.…”