Immunosafe(r)-by-design nanoparticles: Molecular targets and cell signaling pathways in a next-generation model proxy for humans.

Nanotechnology research covers a wide field of studies pointing to design and shape complex matter in a scale between 1 and 100nm, with unique size-depending properties and applications. The value and potential of engineered nanoparticles in human diagnostics and therapies essentially relay on their safety and biocompatibility. Entering a cell, in fact, these particles take complex interactions with the surrounding biological environment, dramatically changing their own identity. The formation of a custom-made protein corona is the first signal of their interplay with the cell defensive mechanisms, and a major issue in their application in medicine. Preliminary in-depth studies in model organisms have been developed to assess immunological safety and competence in facing the host immune system and its defensive response. New affordable animal models are emerging in pilot nano-response and safety studies. Sea urchins, benthic marine Echinoderms, have a wide and very efficient immune system working with innate defense mechanisms and are widely used in immune studies. Nano-safety studies have been showing that the sea urchin Paracentrotus lividus displays an excellent sensing system and high defensive capability, joined to the availability of easily accessible immune cells. As in mammals, nanoparticle recognition and interaction activate specific signaling pathways, metabolic rewiring and homeostasis maintenance. In this chapter, we point to the value of planning new research and developing nano-immune studies using an easy nonmammalian next-generation model, able to unravel new specific response mechanisms to nanoparticles.

Interaction of an opportunistic fungus Purpureocillium lilacinum with human macrophages and dendritic cells

Introduction Purpureocillium lilacinum is emerging as a causal agent of hyalohyphomycosis that is refractory to antifungal drugs; however, the pathogenic mechanisms underlying P. lilacinum infection are not understood. In this study, we investigated the interaction of P. lilacinum conidia with human macrophages and dendritic cells in vitro. Methods Spores of a P. lilacinum clinical isolate were obtained by chill-heat shock. Mononuclear cells were isolated from eight healthy individuals. Monocytes were separated by cold aggregation and differentiated into macrophages by incubation for 7 to 10 days at 37°C or into dendritic cells by the addition of the cytokines human granulocyte-macrophage colony stimulating factor and interleukin-4. Conidial suspension was added to the human cells at 1:1, 2:1, and 5:1 (conidia:cells) ratios for 1h, 6h, and 24h, and the infection was evaluated by Giemsa staining and light microscopy. Results After 1h interaction, P. lilacinum conidia were internalized by human cells and after 6h contact, some conidia became inflated. After 24h interaction, the conidia produced germ tubes and hyphae, leading to the disruption of macrophage and dendritic cell membranes. The infection rate analyzed after 6h incubation of P. lilacinum conidia with cells at 2:1 and 1:1 ratios was 76.5% and 25.5%, respectively, for macrophages and 54.3% and 19.5%, respectively, for cultured dendritic cells. Conclusions P. lilacinum conidia are capable of infecting and destroying both macrophages and dendritic cells, clearly demonstrating the ability of this pathogenic fungus to invade human phagocytic cells. .