Extracellular Vesicles and Immunity: At the Crossroads of Cell Communication.

Extracellular vesicles (EVs), comprising exosomes and microvesicles, are small membranous structures secreted by nearly all cell types. They have emerged as crucial mediators in intercellular communication, playing pivotal roles in diverse physiological and pathological processes, notably within the realm of immunity. These roles go beyond mere cellular interactions, as extracellular vesicles stand as versatile and dynamic components of immune regulation, impacting both innate and adaptive immunity. Their multifaceted involvement includes immune cell activation, antigen presentation, and immunomodulation, emphasising their significance in maintaining immune homeostasis and contributing to the pathogenesis of immune-related disorders. Extracellular vesicles participate in immunomodulation by delivering a wide array of bioactive molecules, including proteins, lipids, and nucleic acids, thereby influencing gene expression in target cells. This manuscript presents a comprehensive review that encompasses in vitro and in vivo studies aimed at elucidating the mechanisms through which EVs modulate human immunity. Understanding the intricate interplay between extracellular vesicles and immunity is imperative for unveiling novel therapeutic targets and diagnostic tools applicable to various immunological disorders, including autoimmune diseases, infectious diseases, and cancer. Furthermore, recognising the potential of EVs as versatile drug delivery vehicles holds significant promise for the future of immunotherapies.

Chemical Characterization, Free Radical Scavenging, and Cellular Antioxidant Properties of the Egadi Island Endemic Brassica macrocarpa Guss Leaf Extract.

The genus Brassica is an important source of food in the Mediterranean diet with documented nutritional and medicinal properties. However, few studies have investigated the phytochemical composition and the biological activity of wild Sicilian taxa. Thus, we aimed to study the chemical profile and the antioxidant potential, in vitro and in LPS-stimulated RAW 264.7 cells, of a methanolic extract of leaves of wild Brassica macrocarpa Guss (B. macrocarpa) (Egadi Islands; Sicily-Italy). B. macrocarpa methanolic extract showed a large amount of glucosinolates and different phenolic compounds. It exhibited antioxidant activity in the DPPH assay and in LPS-stimulated RAW 264.7 cells, being able to reduce NO and ROS levels and NOS2 mRNA expression. Our study demonstrated that Sicilian B. macrocarpa methanolic extract, in LPS-stimulated macrophages, efficiently counteracts oxidative stress and displays radical scavenging activity. Future studies are required to identify the contribution of the single phytocomponents, to characterize the action mechanism, and to reveal possible applications in human health.

Extracellular vesicles from PBDE-47 treated M(LPS) THP-1 macrophages modulate the expression of markers of epithelial integrity, EMT, inflammation and muco-secretion in ALI culture of airway epithelium.

AIMS: The lung epithelial cells form a physical barrier to the external environment acting as the first line of defence against potentially harmful environmental stimuli. These cells interact with several other cellular components, of which macrophages are some of the most relevant. We analysed the effects of the PBDE-47 on the microRNA cargo of THP-1 macrophage like derived small Extracellular Vesicles (sEVs) and the effects on A549 lung epithelial cells. MAIN METHODS: sEVs from M(LPS) THP-1 macrophage-like cells after PBDE-47 treatment (sEVsPBDE+LPS) were characterized by nanoparticle tracking analysis and their microRNA cargo studied by qPCR. Confocal microscopy was applied to study sEVs cellular uptake by A549 cells. The expression of tight junctions (TJs), adhesion molecules, inflammation markers and mucus production in A549 cultured in air liquid interface (ALI) conditions were studied by Real Time PCR and confocal microscopy. KEY FINDINGS: sEVsPBDE+LPS microRNA cargo analysis showed that the PBDE-47 modulated the expression of the miR-15a-5p, miR29a-3p, miR-143-3p and miR-122-5p. Furthermore, ALI cultured A549 cells incubated with sEVsPBDE+LPS showed that zonula occludens-1 (p ≤ 0.04), claudin (p ≤ 0.02), E-cadherin (p ≤ 0.006) and Vimentin (p ≤ 0.0008) mRNAs were increased in A549 cells after sEVsPBDE+LPS treatment. Indeed, Interleukin (IL)-8 (p ≤ 0.008) and mucin (MUC5AC and MUC5B) (p ≤ 0.03 and p ≤ 0.0001) mRNA expression were up- and down-regulated, respectively. SIGNIFICANCE: PBDE-47 treated macrophages secrete sEVs with altered microRNA cargo that affect the mRNA expression of TJs, adhesion molecules, cytokines and EMT markers damaging the normal function of the lung epithelium, potentially contributing to the development of lung diseases.

Synthesis and Characterization of a Biocompatible Nanoplatform Based on Silica-Embedded SPIONs Functionalized with Polydopamine.

Superparamagnetic iron oxide nanoparticles (SPIONs) have gained increasing interest in nanomedicine, but most of those that have entered the clinical trials have been withdrawn due to toxicity concerns. Therefore, there is an urgent need to design low-risk and biocompatible SPION formulations. In this work, we present an original safe-by-design nanoplatform made of silica nanoparticles loaded with SPIONs and decorated with polydopamine (SPIONs@SiO2-PDA) and the study of its biocompatibility performance by an ad hoc thorough in vitro to in vivo nanotoxicological methodology. The results indicate that the SPIONs@SiO2-PDA have excellent colloidal stability in serum-supplemented culture media, even after long-term (24 h) exposure, showing no cytotoxic or genotoxic effects in vitro and ex vivo. Physiological responses, evaluated in vivo using Caenorhabditis elegans as the animal model, showed no impact on fertility and embryonic viability, induction of an oxidative stress response, and a mild impact on animal locomotion. These tests indicate that the synergistic combination of the silica matrix and PDA coating we developed effectively protects the SPIONs, providing enhanced colloidal stability and excellent biocompatibility.

Impact of the flame retardant 2,2'4,4'-tetrabromodiphenyl ether (PBDE-47) in THP-1 macrophage-like cell function via small extracellular vesicles.

2,2'4,4'-tetrabromodiphenyl ether (PBDE-47) is one of the most widespread environmental brominated flame-retardant congeners which has also been detected in animal and human tissues. Several studies have reported the effects of PBDEs on different health issues, including neurobehavioral and developmental disorders, reproductive health, and alterations of thyroid function. Much less is known about its immunotoxicity. The aim of our study was to investigate the effects that treatment of THP-1 macrophage-like cells with PBDE-47 could have on the content of small extracellular vesicles' (sEVs) microRNA (miRNA) cargo and their downstream effects on bystander macrophages. To achieve this, we purified sEVs from PBDE-47 treated M(LPS) THP-1 macrophage-like cells (sEVsPBDE+LPS) by means of ultra-centrifugation and characterized their miRNA cargo by microarray analysis detecting the modulation of 18 miRNAs. Furthermore, resting THP-1 derived M(0) macrophage-like cells were cultured with sEVsPBDE+LPS, showing that the treatment reshaped the miRNA profiles of 12 intracellular miRNAs. This dataset was studied in silico, identifying the biological pathways affected by these target genes. This analysis identified 12 pathways all involved in the maturation and polarization of macrophages. Therefore, to evaluate whether sEVsPBDE+LPS can have some immunomodulatory activity, naïve M(0) THP-1 macrophage-like cells cultured with purified sEVsPBDE+LPS were studied for IL-6, TNF-α and TGF-ß mRNAs expression and immune stained with the HLA-DR, CD80, CCR7, CD38 and CD209 antigens and analyzed by flow cytometry. This analysis showed that the PBDE-47 treatment does not induce the expression of specific M1 and M2 cytokine markers of differentiation and may have impaired the ability to make immunological synapses and present antigens, down-regulating the expression of HLA-DR and CD209 antigens. Overall, our study supports the model that perturbation of miRNA cargo by PBDE-47 treatment contributes to the rewiring of cellular regulatory pathways capable of inducing perturbation of differentiation markers on naïve resting M(0) THP-1 macrophage-like cells.