SARS-CoV-2 awakens ancient retroviral genes and the expression of proinflammatory HERV-W envelope protein in COVID-19 patients.

Patients with COVID-19 may develop abnormal inflammatory response, followed in some cases by severe disease and long-lasting syndromes. We show here that in vitro exposure to SARS-CoV-2 activates the expression of the human endogenous retrovirus (HERV) HERV-W proinflammatory envelope protein (ENV) in peripheral blood mononuclear cells from a subset of healthy donors, in ACE2 receptor and infection-independent manner. Plasma and/or sera of 221 COVID-19 patients from different cohorts, infected with successive SARS-CoV-2 variants including the Omicron, had detectable HERV-W ENV, which correlated with ENV expression in T lymphocytes and peaked with the disease severity. HERV-W ENV was also found in postmortem tissues of lungs, heart, gastrointestinal tract, brain olfactory bulb, and nasal mucosa from COVID-19 patients. Altogether, these results demonstrate that SARS-CoV-2 could induce HERV-W envelope protein expression and suggest its involvement in the immunopathogenesis of certain COVID-19-associated syndromes and thereby its relevance in the development of personalized treatment of patients.

Integrated analysis of circulating immune cellular and soluble mediators reveals specific COVID19 signatures at hospital admission with utility for prediction of clinical outcomes.

Coronavirus disease 2019 (COVID19), caused by SARS-CoV-2, is a complex disease, with a variety of clinical manifestations ranging from asymptomatic infection or mild cold-like symptoms to more severe cases requiring hospitalization and critical care. The most severe presentations seem to be related with a delayed, deregulated immune response leading to exacerbated inflammation and organ damage with close similarities to sepsis. Methods: In order to improve the understanding on the relation between host immune response and disease course, we have studied the differences in the cellular (monocytes, CD8+ T and NK cells) and soluble (cytokines, chemokines and immunoregulatory ligands) immune response in blood between Healthy Donors (HD), COVID19 and a group of patients with non-COVID19 respiratory tract infections (NON-COV-RTI). In addition, the immune response profile has been analyzed in COVID19 patients according to disease severity. Results: In comparison to HDs and patients with NON-COV-RTI, COVID19 patients show a heterogeneous immune response with the presence of both activated and exhausted CD8+ T and NK cells characterised by the expression of the immune checkpoint LAG3 and the presence of the adaptive NK cell subset. An increased frequency of adaptive NK cells and a reduction of NK cells expressing the activating receptors NKp30 and NKp46 correlated with disease severity. Although both activated and exhausted NK cells expressing LAG3 were increased in moderate/severe cases, unsupervised cell clustering analyses revealed a more complex scenario with single NK cells expressing more than one immune checkpoint (PD1, TIM3 and/or LAG3). A general increased level of inflammatory cytokines and chemokines was found in COVID19 patients, some of which like IL18, IL1RA, IL36B and IL31, IL2, IFNα and TNFα, CXCL10, CCL2 and CCL8 were able to differentiate between COVID19 and NON-COV-RTI and correlated with bad prognosis (IL2, TNFα, IL1RA, CCL2, CXCL10 and CXCL9). Notably, we found that soluble NKG2D ligands from the MIC and ULBPs families were increased in COVID19 compared to NON-COV-RTI and correlated with disease severity. Conclusions: Our results provide a detailed comprehensive analysis of the presence of activated and exhausted CD8+T, NK and monocyte cell subsets as well as extracellular inflammatory factors beyond cytokines/chemokines, specifically associated to COVID19. Importantly, multivariate analysis including clinical, demographical and immunological experimental variables have allowed us to reveal specific immune signatures to i) differentiate COVID19 from other infections and ii) predict disease severity and the risk of death.

Efficient encapsulation of theranostic nanoparticles in cell-derived exosomes: leveraging the exosomal biogenesis pathway to obtain hollow gold nanoparticle-hybrids.

Exosomes can be considered natural targeted delivery systems able to carry exogenous payloads, drugs or theranostic nanoparticles (NPs). This work aims to combine the therapeutic capabilities of hollow gold nanoparticles (HGNs) with the unique tumor targeting properties provided by exosomes. Here, we tested different methods to encapsulate HGNs (capable of absorbing light in the NIR region for selective thermal ablation) into murine melanoma cells derived exosomes (B16-F10-exos), including electroporation, passive loading by diffusion, thermal shock, sonication and saponin-assisted loading. These methods gave less than satisfactory results: although internalization of relatively large NPs into B16-F10-exos was achieved by almost all the physicochemical methods tested, only about 15% of the exosomes were loaded with NPs and several of those processes had a negative effect regarding the morphology and integrity of the loaded exosomes. In a different approach, B16-F10 cells were pre-incubated with PEGylated HGNs (PEG-HGNs) in an attempt to incorporate the NPs into the exosomal biogenesis pathway. The results were highly successful: exosomes recovered from the supernatant of the cell culture showed up to 50% of HGNs internalization. The obtained hybrid HGN-exosome vectors were characterized with a battery of techniques to make sure that internalization of HGNs did not affect exosome characteristics compared with other strategies. PEG-HGNs were released through the endosomal-exosome biogenesis pathway confirming that the isolated vesicles were exosomes.

Preparation and Identification of Optimal Synthesis Conditions for a Novel Alkaline Anion-Exchange Membrane.

The physicochemical and mechanical properties of new alkaline anion-exchange membranes (AAEMs) based on chitosan (CS) and poly(vinyl alcohol) (PVA) polymers doped with unsupported copper nanoparticles (NPs) and copper exchanged over different porous materials were investigated regarding ion-exchange capacity (IEC), OH- conductivity, water uptake (WU), water vapor permeability (WVP), and thermal and mechanical resistance. The influence of the type of filler included in different morphologies and filler loading has been explored using copper exchanged materials such as the layered porous titanosilicate AM-4, layered stannosilicate UZAR-S3, and zeolites Y, MOR, and BEA. Compared to commercially available anion-exchange membranes, the best performing membranes in terms of WU, IEC, OH- conductivity and WVP in this study were those containing 10 wt % of Cu-AM-4 and Cu-UZAR-S3, although 10 wt % Cu-MOR provided better mechanical strength at close values of WVP and anion conductivity. It was also observed that when Cu was exchanged in a porous silicate matrix, its oxidation state was lower than when embedded as unsupported metal NPs. In addition, the statistical analysis of variance determined that the electrochemical properties of the membranes were noticeably affected by both the type and filler loading, and influenced also by the copper oxidation state and content in the membrane, but their hydrophilic properties were more affected by the polymers. The largest significant effects were noticed on the water sorption and transport properties, which gives scope for the design of AAEMs for electrochemical and water treatment applications.

The effect of PEGylated hollow gold nanoparticles on stem cell migration: potential application in tissue regeneration.

Mesenchymal stem cells (MSCs) not only can be differentiated into different cell types but also have tropism towards injured or inflamed tissues serving as repair cells. Here we have demonstrated that MSCs containing gold nanoparticles (GNPs) whose surface has been functionalized with PEG show accelerated cell migration, successful scaffold colonization and regeneration. We report the impact of GNPs on the migration (by the wound healing assay), and proliferation (by flow cytometry analysis and by the detection of metabolic mitochondrial activity) on the behaviour of different cell lines including MSCs, HeLa cells, and human dermal fibroblasts. We conclude that GNPs are easily internalized by MSCs causing an increase in their migration rate, mediated by actin and tubulin with a 4-fold increased expression level of those proteins. We also demonstrate that MSCs containing GNPs are able to successfully colonize fibrin and PCL-based scaffolds and that an enhanced osteoblastic differentiation is reached when using the nanoparticle-laden cells compared to untreated cells used as a control. These results highlight the potential use of MSCs as therapeutic nanoparticle-carriers in regenerative medicine.