Molecular mechanisms of zinc toxicity in the potworm Enchytraeus crypticus, analysed by high-throughput gene expression profiling

• Published in: The Science of the total environment 2022-06, Vol.825, p.153975-153975, Article 153975
• Main Authors: Gomes, Susana I.L., de Boer, Tjalf E., van Gestel, Cornelis A.M., van Straalen, Nico M., Soares, Amadeu M.V.M., Roelofs, Dick, Amorim, Mónica J.B.
• Format: Article
• Language: English
• Subjects: Animals; AOP (adverse outcome pathway); avoidance behavior; Enchytraeus; environment; gene expression; Gene Expression Profiling; Male; males; microarray technology; Microarrays; nervous system; Oligochaeta - physiology; oocytes; oxidative stress; reactive oxygen species; Reproduction; Soil; Soil Pollutants - analysis; species; Time series; toxicity; zinc; Zinc - analysis
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.153975

Zinc (Zn) is known to be relatively toxic to some soil-living invertebrates including the ecologically important enchytraeid worms. To reveal the molecular mechanisms of zinc toxicity we assessed the gene expression profile of Enchytraeus crypticus (Enchytraeidae), exposed to the reproduction effect concentrations EC10 and EC50, over 4 consecutive days, using a high-throughput microarray (species customized). Three main mechanisms of toxicity to Zn were observed: 1) Zn trafficking (upregulation of zinc transporters, a defence response to regulate the cellular zinc level), 2) oxidative stress (variety of defence mechanisms, triggered by Reactive Oxygen Species (ROS)), and 3) effects on the nervous system (possibly the primary lesion explaining the avoidance behaviour and also why enchytraeids are relatively susceptible to Zn). The adverse outcome at the organism level (reproduction EC50) could be predicted based on gene expression (male gonad development, oocyte maturation), with Zn at the EC50 affecting processes related to higher stress levels. The gene expression response was time-dependent and reflected the cascade of events taking place over-time. The 1 to 4 days of exposure design was a good strategy as it captured the time for sequence of events towards zinc adverse outcomes in E. crypticus. [Display omitted] •The initial (1–4 days) transcriptional response towards zinc exposure was investigated.•A high-throughput (4x180K) microarray for E. crypticus was used.•Key mechanisms included neuronal impacts, Zn trafficking and oxidative stress.•Adverse outcome at organism level (EC50) could be predicted based on gene expression.•Gene expression response was time-dependent and reflected the cascade of events.