Identification of Proteomic Signatures of Exposure to Marine Pollutants in Mussels (Mytilus edulis)

Jia Mi,Susana Cristobal,Itxaso Apraiz

doi:10.1074/mcp.m500333-mcp200

Abstract

Bivalves and especially mussels are very good indicators of marine and estuarine pollution, and so they have been widely used in biomonitoring programs all around the world. However, traditional single parameter biomarkers face the problem of high sensitivity to biotic and abiotic factors. In our study, digestive gland peroxisome-enriched fractions of Mytilus edulis (L., 1758) were analyzed by DIGE and MS. We identified several proteomic signatures associated with the exposure to several marine pollutants (diallyl phthalate, PBDE-47, and bisphenol-A). Animals collected from North Atlantic Sea were exposed to the contaminants independently under controlled laboratory conditions. One hundred and eleven spots showed a significant increase or decrease in protein abundance in the two-dimensional electrophoresis maps from the groups exposed to pollutants. We obtained a unique protein expression signature of exposure to each of those chemical compounds. Moreover a set of proteins composed a proteomic signature in common to the three independent exposures. It is remarkable that the principal component analysis of these spots showed a discernible separation between groups, and so did the hierarchical clustering into four classes. The 14 proteins identified by MS participate in alpha- and beta-oxidation pathways, xenobiotic and amino acid metabolism, cell signaling, oxyradical metabolism, peroxisomal assembly, respiration, and the cytoskeleton. Our results suggest that proteomic signatures could become a valuable tool to monitor the presence of pollutants in field experiments where a mixture of pollutants is often present. Further studies on the identified proteins could provide crucial information to understand possible mechanisms of toxicity of single xenobiotics or mixtures of them in marine ecosystems.

Highlights

Bivalves and especially mussels are very good indicators of marine and estuarine pollution, and so they have been widely used in biomonitoring programs all around the world
Group 2 was exposed to 38.3 ␮g/liter diallyl phthalate (DAP), group 3 was exposed to 0.23 ␮g/liter PBDE-47, and group 4 was exposed to 59.4 ␮g/liter bisphenol A (BPA)
The second group was exposed to 38.3 ␮g/liter DAP, the third group was exposed to 0.23 ␮g/liter PBDE-47, and the fourth group was exposed to 59.4 ␮g/liter BPA

Summary

Introduction

Bivalves and especially mussels are very good indicators of marine and estuarine pollution, and so they have been widely used in biomonitoring programs all around the world. Among the chemical compounds affecting the marine environment, it has been verified that some can induce morphological and functional changes in peroxisomes and peroxisome proliferation. Peroxisome proliferation has been assessed in aquatic sentinel species like mussels and applied as a biomarker of environmental pollution in biomonitoring programs [4]. The detection of peroxisome proliferation by proteomics has been proposed; this approach provides a more complex protein expression signature (PES) and can be applied to field experiments [8]. Proteomics has been well developed in model organisms creating extensive 2-DE databases of proteins [18, 19] and characterizing the response to peroxisome proliferators [20], its feasibility and utility for environmental pollution assessment based on non-model organisms like mussels has yet to be demonstrated

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