Chironomus riparius Proteome Responses to Spinosad Exposure.

Hugo R Monteiro,João L T Pestana,Marco F L Lemos,Amadeu M V M Soares,Bart Devreese

doi:10.3390/toxics8040117

Hugo R Monteiro, João L T Pestana + Show 3 more

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https://doi.org/10.3390/toxics8040117

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Abstract

The potential of proteome responses as early-warning indicators of insecticide exposure was evaluated using the non-biting midge Chironomus riparius (Meigen) as the model organism. Chironomus riparius larvae were exposed to environmentally relevant concentrations of the neurotoxic pesticide spinosad to uncover molecular events that may provide insights on the long-term individual and population level consequences. The iTRAQ labeling method was performed to quantify protein abundance changes between exposed and non-exposed organisms. Data analysis revealed a general dose-dependent decrease in the abundance of globin proteins as a result of spinosad exposure. Additionally, the downregulation of actin and a larval cuticle protein was also observed after spinosad exposure, which may be related to previously determined C. riparius life-history traits impairment and biochemical responses. Present results suggest that protein profile changes can be used as early warning biomarkers of pesticide exposure and may provide a better mechanistic interpretation of the toxic response of organisms, aiding in the assessment of the ecological effects of environmental contamination. This work also contributes to the understanding of the sublethal effects of insecticides in invertebrates and their molecular targets.

Highlights

The study of the impact of stressors on ecological entities is crucial for risk assessment [1].Most often, toxicity testing is based on organism-level responses [2]
Fifteen proteins identified in both iTRAQ runs were considered for quantification analysis, and eight proteins (22.2%) were found to be differentially expressed (Table 2, Figure 1): four proteins belonging to the globin family, one cuticle protein, one actin, one arginine kinase, and one elongation factor
While most ecotoxicoproteomic studies to this date focus on one single concentration of a stressor, the responses observed support the need of using techniques that allow the simultaneous analysis of several samples—especially in an era of increased awareness about non-monotonic dose–responses and its relevance when considering toxicological studies

Summary

Introduction

The study of the impact of stressors on ecological entities is crucial for risk assessment [1].Most often, toxicity testing is based on organism-level responses (e.g., mortality, growth, and behavior) [2]. Xenobiotic concentrations commonly found in the environment may not be sufficient to cause an immediate visible individual-level response [3], and when a response occurs, it may be too late to set off successful environmental management actions. In this sense, there is a need to develop new and sensitive tools that can help determine molecular initiating events that lead to adverse outcomes and be used as early-warning tools to predict ecological adverse effects of stressors. The application of proteomics in ecotoxicology has been expanding in recent years, and while initially most aquatic toxicity studies focused on fish species [6], recent research has Toxics 2020, 8, 117; doi:10.3390/toxics8040117 www.mdpi.com/journal/toxics

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