Silver nanoparticles (AgNPs) have been reported as stressors for the bivalves' immune system at different regulatory levels, impacting the detection step and receptors, and other mediators, as well as effector molecules. However, studies on how AgNPs impact the transmission of signals from receptors and whether they have an effect on mediators and transcription factors are still scarce. This study aims to investigate the effect of 12 hours of in vivo exposure to 100 µg/L of AgNPs on the gene expression of the cytosolic adaptor Myeloid, the differentiation protein 88 (MgMyD88-b), and the interferon regulatory factor (Me4-IRF) in the gills and digestive gland of Mytilus galloprovincialis, before and after blocking two major uptake pathways of nanoparticles (clathrin- and caveolae-mediated endocytosis). The results illustrate a tissue-specific gene expression of the MgMyD88-b and the Me4-IRF in the gills and digestive gland of M. galloprovincialis. In the gills, AgNPs did not significantly impact the expression of the two genes. However, blocking the caveolae-mediated endocytosis decreased the expression of Me4-IRF. However, inhibition of clathrin-mediated endocytosis in the digestive gland recorded a significant decrease in the expression of MgMyD88-b. Overall, the inhibition of the AgNPs' uptake routes have highlighted their potential interference with the immune response through the studied mediators' genes, which need to be studied further in future investigations.
Keywords: Endocytosis; digestive gland; gills; immune response; mussels; signaling pathways.