We report that the immunogenicity of colloidal gold nanoparticles coated with polyvinylpyrrolidone (PVP-AuNPs) in a model organism, the sea urchin Paracentrotus lividus, can function as a proxy for humans for in vitro immunological studies. To profile the immune recognition and interaction from exposure to PVP-AuNPs (1 and 10 μg mL-1), we applied an extensive nano-scale approach, including particle physicochemical characterisation involving immunology, cellular biology, and metabolomics. The interaction between PVP-AuNPs and soluble proteins of the sea urchin physiological coelomic fluid (blood equivalent) results in the formation of a protein "corona" surrounding the NPs from three major proteins that influence the hydrodynamic size and colloidal stability of the particle. At the lower concentration of PVP-AuNPs, the P. lividus phagocytes show a broad metabolic plasticity based on the biosynthesis of metabolites mediating inflammation and phagocytosis. At the higher concentration of PVP-AuNPs, phagocytes activate an immunological response involving Toll-like receptor 4 (TLR4) signalling pathway at 24 hours of exposure. These results emphasise that exposure to PVP-AuNPs drives inflammatory signalling by the phagocytes and the resolution at both the low and high concentrations of the PVP-AuNPs and provides more details regarding the immunogenicity of these NPs.

• Keywords
• Immune metabolic rewiring, Immunoreactivity, Innate defence response, Nano-recognition, Sea urchin immune cells,
• MeSH
• Phagocytes MeSH
• Metal Nanoparticles * toxicity   MeSH
• Humans MeSH
• Paracentrotus * MeSH
• Povidone MeSH
• Gold MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Povidone MeSH
• Gold MeSH

Titanium dioxide nanoparticles (TiO2NPs) are revolutionizing biomedicine due to their potential application as diagnostic and therapeutic agents. However, the TiO2NP immune-compatibility remains an open issue, even for ethical reasons. In this work, we investigated the immunomodulatory effects of TiO2NPs in an emergent proxy to human non-mammalian model for in vitro basic and translational immunology: the sea urchin Paracentrotus lividus. To highlight on the new insights into the evolutionarily conserved intracellular signaling and metabolism pathways involved in immune-TiO2NP recognition/interaction we applied a wide-ranging approach, including electron microscopy, biochemistry, transcriptomics and metabolomics. Findings highlight that TiO2NPs interact with immune cells suppressing the expression of genes encoding for proteins involved in immune response and apoptosis (e.g. NF-κB, FGFR2, JUN, MAPK14, FAS, VEGFR, Casp8), and boosting the immune cell antioxidant metabolic activity (e.g. pentose phosphate, cysteine-methionine, glycine-serine metabolism pathways). TiO2NP uptake was circumscribed to phagosomes/phagolysosomes, depicting harmless vesicular internalization. Our findings underlined that under TiO2NP-exposure sea urchin innate immune system is able to control inflammatory signaling, excite antioxidant metabolic activity and acquire immunological tolerance, providing a new level of understanding of the TiO2NP immune-compatibility that could be useful for the development in Nano medicines.

• Keywords
• Homeostasis restoring, Human gene networks, Innate immunity, Metabolic rewiring, TiO(2)NP-responsive genes,
• MeSH
• Antioxidants metabolism   MeSH
• Water Pollutants, Chemical toxicity   MeSH
• Phagocytosis drug effects   MeSH
• Transcription, Genetic drug effects   MeSH
• Cells, Cultured MeSH
• Nanoparticles toxicity   MeSH
• Paracentrotus cytology   drug effects   immunology   metabolism   MeSH
• Immunity, Innate drug effects   genetics   MeSH
• Titanium toxicity   MeSH
• Cell Survival drug effects   immunology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Antioxidants MeSH
• Water Pollutants, Chemical MeSH
• Titanium MeSH
• titanium dioxide MeSH Browser

Extensive exploitation of titanium dioxide nanoparticles (TiO2NPs) augments rapid release into the marine environment. When in contact with the body fluids of marine invertebrates, TiO2NPs undergo a transformation and adhere various organic molecules that shape a complex protein corona prior to contacting cells and tissues. To elucidate the potential extracellular signals that may be involved in the particle recognition by immune cells of the sea urchin Paracentrotus lividus, we investigated the behavior of TiO2NPs in contact with extracellular proteins in vitro. Our findings indicate that TiO2NPs are able to interact with sea urchin proteins in both cell-free and cell-conditioned media. The two-dimensional proteome analysis of the protein corona bound to TiO2NP revealed that negatively charged proteins bound preferentially to the particles. The main constituents shaping the sea urchin cell-conditioned TiO2NP protein corona were proteins involved in cellular adhesion (Pl-toposome, Pl-galectin-8, Pl-nectin) and cytoskeletal organization (actin and tubulin). Immune cells (phagocytes) aggregated TiO2NPs on the outer cell surface and within well-organized vesicles without eliciting harmful effects on the biological activities of the cells. Cells showed an active metabolism, no oxidative stress or caspase activation. These results provide a new level of understanding of the extracellular proteins involved in the immune-TiO2NP recognition and interaction in vitro, confirming that primary immune cell cultures from P. lividus can be an optional model for swift and efficient immune-toxicological investigations.

• Keywords
• biocorona, echinoderm, extracellular signaling, immune-adhesome, in vitro-ex vivo model, proxy to human,
• MeSH
• Cell Adhesion immunology   MeSH
• Phagocytes immunology   MeSH
• Galectins immunology   MeSH
• Glycoproteins immunology   MeSH
• Sea Urchins immunology   MeSH
• Nanoparticles administration & dosage   MeSH
• Nectins immunology   MeSH
• Paracentrotus immunology   MeSH
• Protein Corona immunology   MeSH
• Proteome immunology   MeSH
• Titanium immunology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Galectins MeSH
• Glycoproteins MeSH
• Nectins MeSH
• Protein Corona MeSH
• Proteome MeSH
• Titanium MeSH
• titanium dioxide MeSH Browser
• toposome glycoprotein complex MeSH Browser

Specimens of Syndesmis aethopharynx Westervelt & Kozloff, 1990 (Umagillidae, Rhabdocoela, Platyhelminthes) were collected from the intestine of several specimens of the sea urchin Paracentrotus lividus (Lamarck, 1816) [2], Hansson, 2001 at the Greek coast. This represents the first report of a species of Syndesmis from Greece. Our study has revealed several previously-unreported morphological details and intraspecific variation, which are added to the species description. The position of S. aethopharynx within Umagillidae is confirmed for the first time through molecular data (based on nuclear 18S rDNA), using both Bayesian and maximum likelihood analyses.

• Keywords
• Echinoidea, Marine microturbellarians, Phylogeny, Taxonomy,
• MeSH
• DNA, Helminth genetics   MeSH
• Phylogeny MeSH
• Host-Parasite Interactions * MeSH
• Paracentrotus parasitology   MeSH
• RNA, Ribosomal, 18S genetics   MeSH
• Animal Distribution * MeSH
• Turbellaria anatomy & histology   genetics   physiology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Greece MeSH
• Mediterranean Sea MeSH
• Names of Substances
• DNA, Helminth MeSH
• RNA, Ribosomal, 18S MeSH