Exposure to low environmental concentrations of manganese, lead, and cadmium alters the serotonin system of blue mussels

Abstract

Serotonin plays a crucial role in mussel survival and reproduction. Although the serotonin system can be affected by metals, the effects of environmental concentrations of metals such as manganese (Mn), lead (Pd), and cadmium (Cd) have never been studied in blue mussels. The present study aimed to determine the effects of exposure to Mn, Pb, or Cd on serotonin levels, monoamine oxidase (MAO) activity, and serotonin transporter (SERT) levels in the blue mussel Mytilus edulis. Mussels were exposed in vivo to increasing and environmentally relevant doses of Mn (10-1000 nM; 0.5-50 mg/L), Pb (0.01-10 nM; 0.002-2 mg/L), or Cd (0.01-10 nM; 0.001-1 mg/L) for 28 d. Serotonin levels, MAO activity, and SERT expression were analyzed in the mussel mantle. Expression of SERT protein was significantly decreased, by up to 81%, following Mn, Pb, or Cd exposure. The activity of MAO in females was almost 2-fold higher, versus males, in nonexposed control mussels. In mussels exposed to 0.1 nM of Pb (0.02 mg/L), MAO activity was increased in males and decreased in females. In Cd-exposed mussels, a sex-dependent, inverted nonmonotonic pattern of MAO activity was observed. These results clearly indicate that low environmental concentrations of Mn, Pb, and Cd affect the serotonin system in blue mussels. Environ Toxicol Chem 2018;37:192-200. C 2017 SETAC

Extracellular Vesicles and Post-Translational Protein Deimination Signatures in Mollusca—The Blue Mussel (Mytilus edulis), Soft Shell Clam (Mya arenaria), Eastern Oyster (Crassostrea virginica) and Atlantic Jacknife Clam (Ensis leei)

“…Invertebrates have naturally occurring heavy metal binding proteins, protecting the animals from excess uptake of metals and associated intoxication [101]. Indeed, even relatively low, but environmentally relevant, doses of metals such as manganese, lead, and cadmium can affect serotonin levels in mussels [102]. Furthermore, increase in toxic metal accumulation, including cadmium, caused by ocean acidification poses as a threat to a number of bivalve species [103].…”

Trends and potential human health risk of trace elements accumulated in transplanted blue mussels during restoration activities of Flekkefjord fjord (Southern Norway)

“…Also an excessive exposure to Mn was demonstrated to be detrimental for organisms, arresting cell growth and division (Kaur et al, 2014 ; Waters et al, 2011 ), reducing iron transport, and causing neurodegenerative disorders in humans (Kaur et al, 2017 ). A recent experimental study showed that chronic exposures to low, environmentally relevant concentrations of Mn can disrupt the serotonin system in the blue mussel by reducing the expression of the serotonin transporter (SERT) in the mantle, limiting serotonin cellular transport (Fraser et al, 2018 ). The expression of SERT is regulated by intracellular concentrations of calcium (Ca 2+ ; Seimandi et al, 2013 ), which can be perturbed by the interaction with Mn and other TEs (Tchounwou et al, 2012 ).…”

Understanding the influence of multiple pollutant stressors on the decline of freshwater mussels in a biodiversity hotspot

“…Similarly, Rogers et al (2018) found that mussels caged in Clinch River sediment (at the same sites that we studied) had reduced growth and survival over a 1-year deployment period in the ZOD and that their reduced growth and survival were correlated with water concentrations of total and dissolved Mn. Although the toxicity of Mn to unionid mussels has not been widely investigated, several studies with marine and neotropical freshwater mussels have indicated acute lethality to larvae at 30 mg Mn/L (Morgan et al, 1986) and sublethal adverse effects on the serotonin system (involved in reproduction and metabolism, and gill, cilia, siphon, and adductor muscle movement) at 0.5 to 50 μg Mn/L and the metabolic suppression of gills at 0.5 mg Mn/ L (Fraser et al, 2018;Oliveira et al, 2018Oliveira et al, , 2019. Additional studies are needed to examine the mechanistic relationships of Mn exposure to mussel health.…”

“…We found little relation between metal concentrations in the environment and in mussel tissue or between site-specific mussel densities and mussel tissue metals. Because metal contaminants alone seem not to explain the decline of mussels in the Clinch River ZOD, contaminant mixtures (e.g., metals, PAHs, and major ions) may be important contributing pollutant stressors to mussels and other sensitive aquatic species (Gillis, 2012;Pandolfo et al, 2012;Gautier et al, 2014;Fraser et al, 2018;Oliveira et al, 2018Oliveira et al, , 2019Prosser et al, 2017). Several previous studies have demonstrated elevated major ion concentrations (e.g., sulfate) in the Clinch River, and especially within the ZOD, and have been related to freshwater mussel declines and coal-related influences (Johnson et al, 2014).…”