Characterization and environmental stress-induced expression profiling of transient receptor potential vanilloid (TRPV) channels in the Pacific oyster (Magallana gigas) following short-heatwave and silver exposure

Abstract

Marine ecosystems are increasingly threatened by the rising frequency of thermal anomalies, such as marine heatwaves (HW), and by the presence of emerging contaminants, including silver nanoparticles (Ag NPs) and its dissociated form into silver ions (Ag⁺). In this context, the present study provides an integrative analysis of the molecular basis of Transient Receptor Potential Vanilloid (TRPV), a family of sensitive channels, under environmentally realistic conditions in the gonad of the Pacific oyster (Magallana gigas). In this study, environmentally relevant concentrations of silver (0.25 μg/L) and a temperature increase of up to 6 °C above natural temperature (16.30 ± 0.82 °C) were applied for 7 days to simulate a realistic short-HW scenario. Four TRPV sequences were identified and, based on phylogenetic analyses, reclassified as TRPVA, TRPVB, and two TRPVC/D paralogs. Among these, TRPVB emerged as the most stress-responsive isoform in the gonad, displaying contrasting expression profiles under HW conditions, with Ag NPs upregulating TRPVB expression whereas Ag⁺ caused its downregulation. Although preliminary, these results suggest that Ag NPs and Ag⁺ activate different signalling pathways, which may be differentially expressed under thermal stress, highlighting the complexity of combined contaminants and climate-related pressures in the Pacific oyster. These findings provide basic knowledge and novel insights into environmental stress responses in marine invertebrates.