SMURF2-mediated ubiquitin signaling plays an essential role in the regulation of PARP1 PARylating activity, molecular interactions, and functions in mammalian cells.

Poly(ADP-ribose) polymerase 1 (PARP1) is a key molecular stress sensor and response mediator implicated in multiple cellular functions in health and diseases. Despite its importance and intrinsic involvement in pivotal molecular and cellular processes, including DNA repair, transcription regulation, chromatin organization, and cell death, the regulatory mechanisms of PARP1 are poorly understood. In this study, we show that SMURF2, a HECT-type E3 ubiquitin ligase and suggested tumor suppressor, physically interacts with PARP1 in different cellular settings, directly ubiquitinates it in vitro and stimulates its PARylation activity in cells, the phenomenon that required SMURF2 E3 ubiquitin ligase function. Intriguingly, in the cellular environment SMURF2 was found to regulate the dynamic exchange of ubiquitin moieties on PARP1, mostly decreasing its monoubiquitination. Through the set of systematic mass spectrometry analyses conducted on SMURF2-modified cells, we identified on PARP1 18 lysine residues (out of 126 present in PARP1) as sites which ubiquitination was considerably affected by SMURF2. Subsequent site-directed mutagenesis coupled with in cellula ubiquitination and PARylation assays unveiled K222 as a critical site enabling a cross talk between SMURF2-modulated monoubiquitination of PARP1 and its activity, and pointed to K498, S507, and a KTR triad (K498/K521/K524) as the main auto-PARylation sites affected by SMURF2. The results also uncovered that SMURF2 controls PARP1 interactome, influencing its functions and expression in a context-dependent manner. Taken together, these findings suggest that SMURF2-mediated ubiquitin signaling plays an essential role in PARP1 regulation, beyond the regulation of its protein expression.

Trichinella spiralis excretory-secretory products downregulate MMP-9 in Dark Agouti rats affected by experimental autoimmune encephalomyelitis.

Matrix metalloproteinases (MMPs), are implicated in the pathogenesis of multiple sclerosis (MS) and in its animal model, experimental autoimmune encephalomyelitis (EAE). Our aim was to investigate whether amelioration of EAE in Dark Agouti (DA) rats, induced by Trichinella spiralis muscle larvae excretory-secretory products (ES L1), could be related to the level and activity of gelatinases, MMP-9 and MMP-2. Serum levels of MMP-9, MMP-2, NGAL/MMP-9, TIMP-1, and cytokines, evaluated by gel-zymography or ELISA, as well as gelatinases and TIMP-1 expression in the spinal cord (SC), were determined in: i) EAE induced, ii) ES L1-treated EAE induced animals. Milder clinical signs in ES L1-treated EAE induced DA rats were accompanied with lower serum levels of MMP-9 and NGAL/MMP-9 complex. However, the correlation between the severity of EAE and the level of serum MMP-9 was found only in the peak of the disease, with MMP-9/TIMP-1 ratio higher in EAE animals without ES L1 treatment. Lower expression of MMP-9 in SC of ES L1-treated, EAE induced rats, correlated with the reduced number of SC infiltrating cells. In SC infiltrates, in the effector and the recovery phase, production of anti-inflammatory cytokines IL-4 and IL-10 was higher in animals treated with ES L1 prior to EAE induction, compared to untreated EAE animals. Reduced expression of MMP-9 in SC tissue, which correlated with the reduced number of infiltrating cells, might be ascribed to regulatory mechanisms, among which is IL-10.

Erector spinae plane block reduces pain after laparoscopic cholecystectomy.

PURPOSE: After laparoscopic cholecystectomy patients have moderate pain in the early postoperative period. According to several studies an erector spinae plane (ESP) block can be a valuable part of multimodal analgesia. Our intention was to evaluate how ESP block influences postoperative pain scores and opioid consumption after laparoscopic cholecystectomy. METHODS: This single-blinded, prospective, randomized study included 60 patients undergoing laparoscopic cholecystectomy to receive either bilateral ESP block at the Th 7 level (n = 30) with 20 ml of 0.25% levobupivacaine plus dexamethasone 2 mg per side, or standard multimodal analgesia (n = 30). Patients from the standard multimodal analgesia group received tramadol 100 mg at the end of the procedure. Postoperative analgesia for both groups was acetaminophen 1 g/8 h i.v. and ketorolac 30 mg/8 h. Tramadol 1 mg/kg was a rescue treatment for pain breakthrough (numeric rating scale/NRS ≥ 6) in both groups. Pain at rest was recorded at 10 min, 30 min, 2 h, 4 h, 8 h, 12 h and 24 h after surgery using NRS (0-10). RESULTS: An ESP block significantly reduced postoperative pain scores compared to standard multimodal analgesia after 10 min (p = 0.011), 30 min (p = 0.004), 2 h (p = 0.011), 4 h (p = 0.003), 8 h (p = 0.013), 12 h (p = 0.004) and 24 h (p = 0.005). Tramadol consumption was significantly lower in the ESP group 25.02 ± 56.8g than in the standard analgesia group 208.3 ± 88.1g (p < 0.001). CONCLUSION: An ESP block can provide superior postoperative analgesia and reduction in opioid requirement after laparoscopic cholecystectomy.

Trichinella spiralis muscle larvae release extracellular vesicles with immunomodulatory properties.

AIMS: Extracellular vesicles (EVs) represent a newly discovered but universal communication tool between cells or organisms. However, few data exist on nematode EVs and none for Trichinella spiralis. Here, we aimed to investigate whether T spiralis muscle larvae produce EVs, whether they carry immunomodulatory proteins and whether they have a role in immunomodulation as a component of excretory-secretory muscle larvae products (ES L1). METHODS AND RESULTS: EVs were enriched from conditioned medium of T spiralis muscle larvae. Transmission electron microscopy images showed T spiralis EVs to be 30-80 nm in size, and Western blot confirmed the presence of two out of three glycoproteins with the immunodominant epitope characteristic for muscle larvae of the genus Trichinella. Using a peripheral blood mononuclear cell (PBMC) stimulation assay, it was shown that these EVs elevated production of IL10 and IL6. CONCLUSION: T spiralis muscle larvae produce EVs. Those EVs carry immunomodulatory proteins and have the capacity independently to induce regulatory responses in the same way as the T spiralis excretory-secretory muscle larvae products from which they were isolated.

Synthesis, antitumor activity and DNA binding features of benzothiazolyl and benzimidazolyl substituted isoindolines.

In this paper novel isoindolines substituted with cyano and amidino benzimidazoles and benzothiazoles were synthesized as new potential anti-cancer agents. The new structures were evaluated for antiproliferative activity, cell cycle changes, cell death, as well as DNA binding and topoisomerase inhibition properties on selected compounds. Results showed that all tested compounds exerted antitumor activity, especially amidinobenzothiazole and amidinobenzimidazole substituted isoindolin-1-ones and benzimidazole substituted 1-iminoisoindoline that showed antiproliferative effect in the submicromolar range. Moreover, the DNA-binding properties of selected compounds were evaluated by biophysical and biochemical approaches including thermal denaturation studies, circular dichroism spectra analyses and topoisomerase I/II inhibition assays and results identified some of them as strong DNA ligands, harboring or not additional topoisomerase II inhibition and able to locate in the nucleus as determined by fluorescence microscopy. In conclusion, we evidenced novel cyano- and amidino-substituted isoindolines coupled with benzimidazoles and benzothiazoles as topoisomerase inhibitors and/or DNA binding compounds with potent antitumor activities.

Generation of SMURF2 knockout human cells using the CRISPR/Cas9 system.

The HECT domain E3 ubiquitin ligase SMURF2 regulates stability of several key protein targets involved in tumorigenesis, cell proliferation, migration, differentiation, and senescence. While altered levels and aberrant cellular distribution of SMURF2 were reported in different types of cancer, its role in tumorigenesis is far from understood. To elucidate the role of SMURF2 in cancer, appropriate human cancer cell models are needed. Here, we describe approaches that can be used to generate human normal and cancer cell strains knocked-out for SMURF2 using the clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) gene-editing technology.

Challenges for Super-Resolution Localization Microscopy and Biomolecular Fluorescent Nano-Probing in Cancer Research.

Understanding molecular interactions and regulatory mechanisms in tumor initiation, progression, and treatment response are key requirements towards advanced cancer diagnosis and novel treatment procedures in personalized medicine. Beyond decoding the gene expression, malfunctioning and cancer-related epigenetic pathways, investigations of the spatial receptor arrangements in membranes and genome organization in cell nuclei, on the nano-scale, contribute to elucidating complex molecular mechanisms in cells and tissues. By these means, the correlation between cell function and spatial organization of molecules or molecular complexes can be studied, with respect to carcinogenesis, tumor sensitivity or tumor resistance to anticancer therapies, like radiation or antibody treatment. Here, we present several new applications for bio-molecular nano-probes and super-resolution, laser fluorescence localization microscopy and their potential in life sciences, especially in biomedical and cancer research. By means of a tool-box of fluorescent antibodies, green fluorescent protein (GFP) tagging, or specific oligonucleotides, we present tumor relevant re-arrangements of Erb-receptors in membranes, spatial organization of Smad specific ubiquitin protein ligase 2 (Smurf2) in the cytosol, tumor cell characteristic heterochromatin organization, and molecular re-arrangements induced by radiation or antibody treatment. The main purpose of this article is to demonstrate how nano-scaled distance measurements between bio-molecules, tagged by appropriate nano-probes, can be applied to elucidate structures and conformations of molecular complexes which are characteristic of tumorigenesis and treatment responses. These applications open new avenues towards a better interpretation of the spatial organization and treatment responses of functionally relevant molecules, at the single cell level, in normal and cancer cells, offering new potentials for individualized medicine.

Fast dendritic cells matured with Poly (I:C) may acquire tolerogenic properties.

BACKGROUND AIMS: Because of the labor-intensive and time-consuming conventional protocols for the generation of dendritic cells (DCs) as the most promising tools for anti-cancer therapy that enable the induction of a T-helper (Th)1-mediated anti-tumor immune response, the use of short-term protocols has been proposed. However, data on the applicability of such protocols in cancer immunotherapy are quite limited. METHODS: We compared the phenotypic and functional capability of fast DCs (fDCs) differentiated for 24 h and then matured for 48 h with Poly (I:C), a strong Th1-promoting agent, with donor-matched conventional DCs (cDCs) differentiated for 5 days and matured likewise. RESULTS: Of 12 donors tested, we identified seven whose monocytes failed to develop into immunogenic DCs through the use of fDC protocol, on the basis of incomplete downregulation of CD14, low expression of CD1a and macrophage-like morphology. Such fDCs have significantly lower expression of CD83, CD86, CCR7 and CD40, weaker allo-stimulatory Th1- and Th17-polarizing capacity caused by poor production of interleukin (IL)-12p70 and IL-23 and high production of IL-10, and prominent Th2-polarizing capacity, compared with donor-matched cDCs. Furthermore, such fDCs had tolerogenic properties as judged by higher expression of indolamine dioxigenase-3, IDO-1 and IL-1ß and induction of a higher percentage of CD4(+)CD25(+)FoxP3(+) T cells. These findings correlated with increased transforming growth factor (TGF)-ß production by fDC-primed CD3(+)T cells and their stronger anti-proliferative capacity. CONCLUSIONS: We emphasize that although fDCs could probably be applied as an alternative to cDCs for cancer therapy, the fDC protocol should not be applied to donors whose DCs acquire tolerogenic capabilities.

Necrosis and apoptosis in Trichinella spiralis-mediated tumour reduction.

It is known that infection with different pathogens, including helminths, can alter the progression of malignant or other diseases. We studied the effect of chronic Trichinella spiralis infection or muscle larvae excretory-secretory (ES L1) antigens on the malignant tumour growth in the mouse melanoma model system in vivo and in vitro. Our results confirmed that chronic infection with T. spiralis possesses the capacity to slow down the progression of tumour growth, resulting in an impressive reduction in tumour size. We found that the phenomenon could, at least partially, be related to a lower level of tumour necrosis compared to necrosis present in control animals with progressive malignancy course. An increased apoptotic potential among the low percentage of cells within the total tumour cell number in vivo was also observed. ES L1 antigen, as a parasitic product that is released during the chronic phase of infection, reduced the survival and slightly, but significantly increased the apoptosis level of melanoma cells in vitro. Our results imply that powerful Trichinella anti-malignance capacity does not rely only on necrosis and apoptosis but other mechanisms through which infection or parasite products manipulate the tumor establishment and expansion should be considered.

Running for time: circadian rhythms and melanoma.

Circadian timing system includes an input pathway transmitting environmental signals to a core oscillator that generates circadian signals responsible for the peripheral physiological or behavioural events. Circadian 24-h rhythms regulate diverse physiologic processes. Deregulation of these rhythms is associated with a number of pathogenic conditions including depression, diabetes, metabolic syndrome and cancer. Melanoma is a less common type of skin cancer yet more aggressive often with a lethal ending. However, little is known about circadian control in melanoma and exact functional associations between core clock genes and development of melanoma skin cancer. This paper, therefore, comprehensively analyses current literature data on the involvement of circadian clock components in melanoma development. In particular, the role of circadian rhythm deregulation is discussed in the context of DNA repair mechanisms and influence of UV radiation and artificial light exposure on cancer development. The role of arylalkylamine N-acetyltransferase (AANAT) enzyme and impact of melatonin, as a major output factor of circadian rhythm, and its protective role in melanoma are discussed in details. We hypothesise that further understanding of clock genes' involvement and circadian regulation might foster discoveries in the field of melanoma diagnostics and treatment.

Synthesis and in vitro antiproliferative evaluation of novel N-alkylated 6-isobutyl- and propyl pyrimidine derivatives.

A series of novel N-alkylated C-6-isobutyl- or -propyl pyrimidine derivatives were synthesized and their antiproliferative effect was evaluated on a panel of tumor cell lines including leukemia cell line K562 and normal diploid human fibroblasts. N-methoxymethylated 5-methylpyrimidin-2,4-dione with di(benzyloxy)isobutyl at C-6 (14b) showed the strongest effect on the cell growth at micromolar concentrations. Mechanisms of action for the lipophilic compound 14b predicted in silico, pointed to its anticancer and antimetastatic potential exerted through inhibition of DNA or RNA polymerases and adhesion molecules. The latter mechanism has been supported in vitro for adherent tumor cell lines.

Eco-Friendly Extraction: A green approach to maximizing bioactive extraction from pumpkin (Curcubita moschata L.).

The research focused on optimizing the accelerated solvent extraction (ASE) of carotenoids and polyphenols from pumpkin powder. The study optimized accelerated solvent extraction (ASE) of carotenoids and polyphenols from pumpkin powder. Using a mix of standard score (SS) and artificial neural network (ANN) methods, the extraction process was fine-tuned. The ANN model assessed extraction parameters' significance, achieving high predictability for total carotenoid content (TCC), total phenolic content (TPC), and free radical scavenging capacity (DPPH and ABTS methods). The analysis highlighted the most effective extraction at 50 % concentration, 120 °C temperature, 5 min duration, and 2 cycles, yielding high carotenoid and phenolic content (TCC 571.49 µg/g, TPC 7.85 mg GAE/g). HPLC-DAD profiles of the optimized ASE extract confirmed major carotenoids and phenolic compounds. Strong correlations were found between bioactive compounds and antioxidant activity, emphasizing potential health benefits.

Trichinella spiralis shares epitopes with human autoantigens.

Like other helminths, Trichinella spiralis has evolved strategies to allow it to survive in the host organism, including the expression of epitopes similar to those present in either expressed or hidden host antigens. To identify T. spiralis-derived antigens that are evolutionarily conserved in the parasite and its host and that could be responsible for its evasion of the host immune response, we examined the reactivity of six different types of autoantibodies to T. spiralis larvae from muscle. T. spiralis antigens that share epitopes with human autoantigens were identified by assessing the cross-reactivity of autoantibody-containing serum samples with T. spiralis antigens in the absence of specific anti-parasite antibodies. Of the 55 autoantibody-containing human serum samples that we analysed by immunohistological screening, 24 (43.6%) recognised T. spiralis muscle larvae structures such as the subcuticular region, the genital primordium or the midgut. Using Western blots, we demonstrated that the same sera reacted with 24 protein components of T. spiralis muscle larvae excretory-secretory L1 antigens. We found that the human autoantibodies predominantly bound antigens belonging to the TSL1 group; more specifically, the autoantibody-containing sera reacted most frequently with the 53-kDa component. Thus, this protein is a good candidate for further studies of the mechanisms of T. spiralis-mediated immunomodulation.

Trichinellosis in Serbia has become a rare event - one outbreak with pulmonary complications.

An outbreak of trichinellosis occurred in Stari Banovci, a settlement in the municipality of Stara Pazova, Srem, Republic of Serbia, in March-April 2019. A total of 28 persons were exposed and trichinellosis was confirmed in 24 of them. This outbreak involved members of eight families, their relatives and friends. The infection, due to Trichinella spiralis (Owen, 1835), was associated with consumption of pork sausages procured in a local butcher's shop. The trace-back study revealed that the meat originated from swine that was raised on a small farm belonging to the owner of the shop, who did not have permission from the Veterinary Directorate for slaughtering animals and who put on the market sausages prepared from uninspected meat. Trichinellosis was accompanied by typical clinical symptoms. However, the unusual occurrence of high percentage of pulmonary complications was noticed. The description of this outbreak indicates that medical practitioners should initiate treatment immediately in cases of high suspicion of trichinellosis, even if the serology is negative, to prevent the complications of the disease. In spite of significant achievements in the control of Trichinella infection among domestic pigs and humans in the last 10 years, it is obvious that such cases of breeding animals under inappropriate conditions, slaughtering them without approval and placing uninspected pork on the market represent a source of sporadic outbreaks in Serbia.

Immunomodulatory components of Trichinella spiralis excretory-secretory products with lactose-binding specificity.

The immunomodulatory potential of Trichinella spiralis muscle larvae excretory-secretory products (ES L1) has been well documented in vitro on dendritic cells (DCs) and in animal models of autoimmune diseases. ES L1 products possess the potential to induce tolerogenic DCs and consequently trigger regulatory mechanisms that maintain immune homeostasis. The use of ES L1 as a potential treatment for various inflammatory disorders proved to be beneficial in animal models, although the precise immunomodulatory factors have not yet been identified. This study aimed at the isolation and characterization of ES L1 components that possess galectin family member properties. Galectin-1-like proteins (TsGal-1-like) were isolated from ES L1 based on the assumption of the existence of a lactose-specific carbohydrate-recognition domain and were recognized by anti-galectin-1 antibodies in Western blot. This TsGal-1-like isolate, similar to galectin-1, induced DCs with tolerogenic properties and hence, the capacity to polarize T cell response towards a regulatory type. This was reflected by a significantly increased percentage of CD4+CD25+Foxp3+ regulatory T cells and significantly increased expression of IL-10 and TGF-ß within this cell population. Proteomic analysis of TsGal-1-like isolate by mass spectrometry identified nineteen proteins, seven with annotated function after blast analysis against a database for T. spiralis and the UniProt database. To our surprise, none of the identified proteins possesses homology with known galectin family members. Nevertheless, the isolated components of ES L1 possess certain galectin-1 properties, such as specific lactose binding and the potential to elicit a regulatory immune response, so it would be worth further investigating the structure of sugar binding within isolated proteins and its biological significance.

Serum-derived extracellular vesicles: Novel biomarkers reflecting the disease severity of COVID-19 patients.

COVID-19 is characterized by a wide spectrum of disease severity, whose indicators and underlying mechanisms need to be identified. The role of extracellular vesicles (EVs) in COVID-19 and their biomarker potential, however, remains largely unknown. Aiming to identify specific EV signatures of patients with mild compared to severe COVID-19, we characterized the EV composition of 20 mild and 26 severe COVID-19 patients along with 16 sex and age-matched healthy donors with a panel of eight different antibodies by imaging flow cytometry (IFCM). We correlated the obtained data with 37 clinical, prerecorded biochemical and immunological parameters. Severe patients' sera contained increased amounts of CD13+ and CD82+ EVs, which positively correlated with IL-6-producing and circulating myeloid-derived suppressor cells (MDSCs) and with the serum concentration of proinflammatory cytokines, respectively. Sera of mild COVID-19 patients contained more HLA-ABC+ EVs than sera of the healthy donors and more CD24+ EVs than severe COVID-19 patients. Their increased abundance negatively correlated with disease severity and accumulation of MDSCs, being considered as key drivers of immunopathogenesis in COVID-19. Altogether, our results support the potential of serum EVs as powerful biomarkers for COVID-19 severity and pave the way for future investigations aiming to unravel the role of EVs in COVID-19 progression.

Myeloid-derived suppressor cells prevent disruption of the gut barrier, preserve microbiota composition, and potentiate immunoregulatory pathways in a rat model of experimental autoimmune encephalomyelitis.

Over-activated myeloid cells and disturbance in gut microbiota composition are critical factors contributing to the pathogenesis of Multiple Sclerosis (MS). Myeloid-derived suppressor cells (MDSCs) emerged as promising regulators of chronic inflammatory diseases, including autoimmune diseases. However, it remained unclear whether MDSCs display any therapeutic potential in MS, and how this therapy modulates gut microbiota composition. Here, we assessed the potential of in vitro generated bone marrow-derived MDSCs to ameliorate experimental autoimmune encephalomyelitis (EAE) in Dark Agouti rats and investigated how their application associates with the changes in gut microbiota composition. MDSCs differentiated with prostaglandin (PG)E2 (MDSC-PGE2) and control MDSCs (differentiated without PGE2) displayed strong immunosuppressive properties in vitro, but only MDSC-PGE2 significantly ameliorated EAE symptoms. This effect correlated with a reduced infiltration of Th17 and IFN-γ-producing NK cells, and an increased proportion of regulatory T cells in the CNS and spleen. Importantly, both MDSCs and MDSC-PGE2 prevented EAE-induced reduction of gut microbiota diversity, but only MDSC-PGE2 prevented the extensive alterations in gut microbiota composition following their early migration into Payer's patches and mesenteric lymph nodes. This phenomenon was related to the significant enrichment of gut microbial taxa with potential immunoregulatory properties, as well as higher levels of butyrate, propionate, and putrescine in feces. This study provides new insights into the host-microbiota interactions in EAE, suggesting that activated MDSCs could be potentially used as an efficient therapy for acute phases of MS. Considering a significant association between the efficacy of MDSC-PGE2 and gut microbiota composition, our findings also provide a rationale for further exploring the specific microbial metabolites in MS therapy.

Harnessing immunomodulatory mechanisms of Trichinella spiralis to design novel nanomedical approaches for restoring self-tolerance in autoimmunity.

The rapid increase in the prevalence of autoimmune diseases in recent decades, especially in developed countries, coincided with improved living conditions and healthcare. Part of this increase could be ascribed to the lack of exposure to infectious agents like helminths that co-evolved with us and display potent immune regulatory actions. In this review we discussed many investigations, including our own, showing that Trichinella spiralis via its excretory-secretory products attenuate Th1/Th17 immunopathological response in autoimmunity and potentiate the protective Th2 and or regulatory T cell response, acting as an effective induction of tolerogenic dendritic cells (DCs), and probably mimicking the autoantigen in some diseases. A recent discovery of T. spiralis extracellular vesicles (TsEVs) suggested that inducing a complex regulation of the immune response requires simultaneous delivery of different signals in nano-sized packages. Indeed, different artificial nanomedical approaches discussed here suggested that co-delivery of multiple signals via nanoparticles is the most promising strategy for the treatment of autoimmune diseases. Although a long way is ahead of us before we could completely replicate natural nano-delivery systems which are both safe and potent in restoring self-tolerance, a clear path is being opened from a careful examination of parasite-host interactions.

Reduced Expression of Autophagy Markers and Expansion of Myeloid-Derived Suppressor Cells Correlate With Poor T Cell Response in Severe COVID-19 Patients.

Widespread coronavirus disease (COVID)-19 is causing pneumonia, respiratory and multiorgan failure in susceptible individuals. Dysregulated immune response marks severe COVID-19, but the immunological mechanisms driving COVID-19 pathogenesis are still largely unknown, which is hampering the development of efficient treatments. Here we analyzed ~140 parameters of cellular and humoral immune response in peripheral blood of 41 COVID-19 patients and 16 age/gender-matched healthy donors by flow-cytometry, quantitative PCR, western blot and ELISA, followed by integrated correlation analyses with ~30 common clinical and laboratory parameters. We found that lymphocytopenia in severe COVID-19 patients (n=20) strongly affects T, NK and NKT cells, but not B cells and antibody production. Unlike increased activation of ICOS-1+ CD4+ T cells in mild COVID-19 patients (n=21), T cells in severe patients showed impaired activation, low IFN-γ production and high functional exhaustion, which correlated with significantly down-regulated HLA-DR expression in monocytes, dendritic cells and B cells. The latter phenomenon was followed by lower interferon responsive factor (IRF)-8 and autophagy-related genes expressions, and the expansion of myeloid derived suppressor cells (MDSC). Intriguingly, PD-L1-, ILT-3-, and IDO-1-expressing monocytic MDSC were the dominant producers of IL-6 and IL-10, which correlated with the increased inflammation and accumulation of regulatory B and T cell subsets in severe COVID-19 patients. Overall, down-regulated IRF-8 and autophagy-related genes expression, and the expansion of MDSC subsets could play critical roles in dysregulating T cell response in COVID-19, which could have large implications in diagnostics and design of novel therapeutics for this disease.

DC-SIGN signalling induced by Trichinella spiralis products contributes to the tolerogenic signatures of human dendritic cells.

Tolerogenic dendritic cells (tolDCs) are central players in the maintenance of immune tolerance and thereby have been identified as the most favourable candidates for cell therapy of autoimmune diseases. We have recently shown that excretory-secretory products (ES L1) released by Trichinella spiralis larvae induce stable human tolDCs in vitro via Toll-like receptor 2 (TLR2) and TLR4. However, engagement of these receptors did not fully explain the tolerogenic profile of DCs. Here, we observed for the first time that dendritic cell-specific ICAM-3 grabbing non-integrin (DC-SIGN) interacts with highly glycosylated ES L1 and contributes to the generation of ES L1-induced tolDCs. Blocking DC-SIGN interfered with the ES L1-induced higher expression of CD40 and CCR7 and the production of IL-10 and TGF-ß by DCs. The cooperation of TLR2, TLR4 and DC-SIGN receptors is of importance for the capacity of DCs to prime T cell response toward Th2 and to induce expansion of CD4+CD25+Foxp3+ T cells, as well as for the production of IL-10 and TGF-ß by these cells. Overall, these results indicate that induction of tolDCs by ES L1 involves engagement of multiple pattern recognition receptors namely, TLR2, TLR4 and DC-SIGN.