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Objectives: To examine changes in serum levels of the bone remodelling molecules dickkopf-1 (Dkk-1), sclerostin, wingless-type protein-3a (Wnt-3a), and bone morphogenetic protein-7 (BMP-7) during 6 months of anti-tumour necrosis factor (anti-TNF) treatment in ankylosing spondylitis (AS) patients with high disease activity. Method: We included 40 patients with axial AS: 20 patients with high disease activity were assigned to treatment with TNF inhibitor and 20 with low disease activity were assigned to non-steroidal anti-inflammatory drug (NSAID) treatment. Markers of bone remodelling and inflammation were assessed at baseline and after 6 months. Results: In the TNF inhibitor-treated group Dkk-1 decreased significantly from 196.8 pg/mL [95% confidence interval (CI) 94.1-399.0] to 116.3 pg/mL (95% CI 38.0-301.6) and BMP-7 increased significantly from 1.4 pg/mL (95% CI 0-23.0) to 20.3 pg/mL (95% CI 4.9-41.3). There was a significant negative correlation between Dkk-1 and BMP-7 at 6 months (r = -0.64, p = 0.004) in this group. Non-parametric regression analysis adjusted for disease duration, age, sex, baseline modified Stoke's Ankylosing Spondylitis Spine Score (mSASSS), and baseline C-reactive protein (CRP) confirmed a statistically significant effect of treatment on time-related changes of Dkk-1 and BMP-7. Erythrocyte sedimentation rate (ESR), CRP, and also the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score decreased significantly in the anti-TNF-treated group. Conclusions: Among the potential biomarkers of bone remodelling in AS, Dkk-1 and BMP-7 displayed significant time alterations and correlative interactions during anti-TNF treatment. [ABSTRACT FROM AUTHOR]

Studying viral infections necessitates well-designed cell culture models to deepen our understanding of diseases and develop effective treatments. In this study, we present a readily available ex vivo 3D co-culture model replicating the human intestinal mucosa. The model combines fully differentiated human intestinal epithelium (HIE) with human monocyte-derived macrophages (hMDMs) and faithfully mirrors the in vivo structural and organizational properties of intestinal mucosal tissues. Specifically, it mimics the lamina propria, basement membrane, and the air-exposed epithelial layer, enabling the pioneering observation of macrophage migration through the tissue to the site of viral infection. In this study, we applied the HIE-hMDMs model for the first time in viral infection studies, infecting the model with two globally significant viruses: severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and human norovirus GII.4. The results demonstrate the model's capability to support the replication of both viruses and show the antiviral role of macrophages, determined by their migration to the infection site and subsequent direct contact with infected epithelial cells. In addition, we evaluated the production of cytokines and chemokines in the intestinal niche, observing an increased interleukin-8 production during infection. A parallel comparison using a classical in vitro cell line model comprising Caco-2 and THP-1 cells for SARS-CoV-2 experiments confirmed the utility of the HIE-hMDMs model in viral infection studies. Our data show that the ex vivo tissue models hold important implications for advances in virology research.IMPORTANCEThe fabrication of intricate ex vivo tissue models holds important implications for advances in virology research. The co-culture model presented here provides distinct spatial and functional attributes not found in simplified models, enabling the evaluation of macrophage dynamics under severe acute respiratory syndrome coronavirus 2 and human norovirus (HuNoV) infections in the intestine. Moreover, these models, comprised solely of primary cells, facilitate the study of difficult-to-replicate viruses such as HuNoV, which cannot be studied in cell line models, and offer the opportunity for personalized treatment evaluations using patient cells. Similar co-cultures have been established for the study of bacterial infections and different characteristics of the intestinal tissue. However, to the best of our knowledge, a similar intestinal model for the study of viral infections has not been published before., Competing Interests: The authors declare no conflict of interest.

The etiology of multisystem inflammatory syndrome in children (MIS-C), frequently observed following COVID-19 infection, remains elusive. This study unveils insights derived from cytokine analysis in the sera of MIS-C patients, both before and after the administration of intravenous immunoglobulin (IVIG) and glucocorticosteroids (GCS). In this study, we employed a comprehensive 45-cytokine profile encompassing a spectrum of widely recognized proinflammatory and antiinflammatory cytokines, as well as growth factors, along with other soluble mediators. The analysis delineates three principal cytokine-concentration patterns evident in the patients' sera. Pattern no.1 predominantly features proinflammatory cytokines (IL-6, IL-15, IL-1ra, granulocyte-macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor α (TNFα), C-X-C motif chemokine ligand 10 (CXCL10/ IP-10), and IL-10) exhibiting elevated concentrations upon admission, swiftly normalizing post-hospital treatment. Pattern no. 2 includes cytokines (IL-17 A, IL-33, IFNγ, vascular endothelial growth factor (VEGF), and programmed death ligand (PD-L1)) with moderately elevated levels at admission, persisting over 7-10 days of hospitalization despite the treatment. Pattern no. 3 comprises cytokines which concentrations escalated after 7-10 days of hospitalization and therapy, including IL-1α, IL-1β, IL-2, IL-13, platelet-derived growth factor AA/BB (PDGF AA/BB). The observed in cytokine profile of MIS-C patients showed a transition from acute inflammation to sustaining inflammation which turned into induction of humoral memory mechanisms and various defense mechanisms, contributing to recovery., (© 2024. The Author(s).)

We present new small-molecular probes targeting the human PD-L1 protein. The molecules were designed by incorporating a newly discovered N-methylmorpholine substituent into a known biphenyl-based structure. Four prototype derivatives of 4-methyl-3,4-dihydro-2H-benzo[b][1,4]oxazine-7-carbonitrile (STD4), comprising a morpholine substituent fused with a biphenyl core at different orientations were first verified for their potential binding to PD-L1 using the molecular docking method. A more favorable 7-phenyl derivative of STD4 was then equipped with an amide bond, pyridine, and either a tris(hydroxymethyl)aminomethane or serinol tail leading to two final molecules. Among them, compound 1c showed activity in three bioassays, i.e., the homogenous time-resolved fluorescence (HTRF) assay, immune checkpoint blockade (ICB) assay, and T-cell activation (TCA) assay. Our work shows that morpholine can substitute for dioxane and becomes a promising component in PD-L1-targeting molecules. This finding unlocks new avenues for optimizing PD-L1-targeting compounds, presenting exciting prospects for future developments in this field., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Urszula Tyrcha is the Chemical Synthesis Specialist at the company RECEPTON Sp. z o.o., Aleksandra Hec-Gałązka is the Chemical Synthesis Specialist at the company RECEPTON Sp. z o.o., Prof. Dr Tad Holak is the CSO of the company RECEPTON Sp. z o.o., Head of Drug Discovery Laboratory Dr Tomasz Sitar is the CEO of the company RECEPTON Sp. z o.o., Head of Protein Engineering Laboratory., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Natural killer (NK) cells play a crucial role in controlling viral infections. The ability to kill infected cells without prior immunization, yet being tolerant to self, healthy cells, depends on the balance of germ-line encoded surface receptors. NK-cell receptors are divided into either activating, leading to activation of NK cell and its cytotoxic and pro-inflammatory activity, or inhibitory, providing tolerance for a target cell. The signals from inhibitory receptors dominate and NK-cell activation requires stimulation of activating receptors. In viral infections, NK-cell interaction with infected cells can result in activation, memory-like NK-cell differentiation, or NK-cell exhaustion, which constitutes one of the viral immune evasion mechanisms. All of these states are associated with the modulation of NK-cell receptor expression. In this review, we summarize the current knowledge of NK-cell receptors and their role in viral infection control, as well as the alterations of their expression observed in acute or chronic infections. We present recently discovered SARS-CoV-2-mediated modulation of NK-cell receptor expression and compare them with other human viral infections. Finally, since modulation of NK-cell receptor activation gives a promising addition to currently used antiviral therapies, we briefly discuss the clinical significance and future perspective of the application of agonists or antagonists of activating and inhibitory receptors, respectively. In sum, our review shows that although much is known about NK-cell receptor biology, a deeper understanding of NK-cell receptors role in viral infections is still needed., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Immunology.)

Globally, an increasing prevalence of colorectal cancer (CRC) prompts a need for the development of new methods for early tumor detection. MicroRNAs (also referred to as miRNAs) are short non-coding RNA molecules that play a pivotal role in the regulation of gene expression. MiRNAs are effectively transferred to extracellular vesicle (EVs) membrane sacs commonly released by cells. Our study aimed to examine the expression of miRNAs in four CRC cell lines and EVs derived from them (tumor EVs) in comparison to the normal colon epithelium cell line and its EVs. EVs were isolated by ultracentrifugation from the culture supernatant of SW480, SW620, SW1116, HCT116 and normal CCD841CoN cell lines and characterized according to the MISEV2023 guidelines. MiRNAs were analyzed by small RNA sequencing and validated by quantitative PCR. The performed analysis revealed 22 common miRNAs highly expressed in CRC cell lines and effectively transferred to tumor EVs, including miR-9-5p, miR-182-5p, miR-196b-5p, miR-200b-5p, miR-200c-3p, miR-425-5p and miR-429, which are associated with development, proliferation, invasion and migration of colorectal cancer cells, as well as in vesicle maturation and transport-associated pathways. In parallel, normal cells expressed miRNAs, such as miR-369 and miR-143, which play a role in proinflammatory response and tumor suppression. The analysis of selected miRNAs in plasma-derived EVs and tumor samples from CRC patients showed the similarity of miRNA expression profile between the patients' samples and CRC cell lines. Moreover, miR-182-5p, miR-196-5p, miR-425-5p and miR-429 were detected in several EV samples isolated from patients' plasma. Our results suggest that miR-182-5p, miR-196b-5p and miR-429 are differentially expressed between EVs from CRC patients and healthy donors, which might have clinical implications.

Chemokines are vital in post-cerebral ischemia inflammatory reactions. We investigate the possible relationship between plasma chemokines and short-term and long-term outcomes after stroke. This study included 235 patients (median age, 72 years; 49.8% female) suffering from ischemic stroke, or transient ischemic attack admitted to the hospital within 24 h of onset. We evaluated chemokines CCL2, CCL5, CXCL8, CXCL9, and CXCL10 in plasma samples collected upon admission. Further, we assessed functional outcomes at 3- and 12-months, all-cause fatality over 5 years, and episodes of delirium within the first 7 days of admission. Multivariate analysis revealed an association between higher CXCL10 levels and an increased risk of poor functional outcomes at 3 months (OR: 3.02, 95%CI: 1.22-7.46, p = 0.016) and 12 months (OR: 2.32, 95%CI: 1.03-5.26, p = 0.043), as well as an increased death risk (HR: 1.79, 95%CI: 1.04-3.07, p = 0.036). High CXCL8 levels independently predicted poor functional outcomes at 12 months (OR: 2.69, 95%CI: 1.39-6.31, p = 0.005) and a higher 5-year case fatality rate (HR: 1.90, 95%CI: 1.23-2.93, p = 0.004). Elevated CXCL9 levels also predicted unfavourable functional outcomes at 12 months (OR: 2.45, 95%CI: 1.07-5.61, p = 0.034). In univariate analysis, increased levels of CXCL8, CXCL9, and CXCL10 showed an association with delirium, although this link was not evident in the multivariate analysis. Plasma CXCL8 and CXCL10 show potential as prognostic biomarkers for stroke outcomes and as therapeutic targets suitable for reverse translation., (© 2024. The Author(s).)

Myocarditis is characterized by an influx of inflammatory cells, predominantly of myeloid lineage. The progression of myocarditis to a dilated cardiomyopathy is markedly influenced by TGF-β signalling. Here, we investigate the role of TGF-β signalling in inflammatory cardiac macrophages in the development of myocarditis and post-inflammatory fibrosis. Experimental autoimmune myocarditis (EAM) was induced in the LysM-Cre × R26-stop-EYFP × Tgfbr2-fl/fl transgenic mice showing impaired TGF-β signalling in the myeloid lineage and the LysM-Cre × R26-stop-EYFP control mice. In EAM, immunization led to acute myocarditis on day 21, followed by cardiac fibrosis on day 40. Both strains showed a similar severity of myocarditis and the extent of cardiac fibrosis. On day 21 of EAM, an increase in cardiac inflammatory macrophages was observed in both strains. These cells were sorted and analysed for differential gene expression using whole-genome transcriptomics. The analysis revealed activation and regulation of the inflammatory response, particularly the production of both pro-inflammatory and anti-inflammatory cytokines and cytokine receptors as TGF-β-dependent processes. The analysis of selected cytokines produced by bone marrow-derived macrophages confirmed their suppressed secretion. In conclusion, our findings highlight the regulatory role of TGF-β signalling in cytokine production within inflammatory cardiac macrophages during myocarditis.

Selective IgA deficiency (sIgAD), common variable immunodeficiency (CVID), and transient hypogammaglobulinemia of infancy (THI) are the most frequent forms of primary antibody deficiencies. Difficulties in initial diagnosis, especially in the early childhood, the familiar occurrence of these diseases, as well as the possibility of progression to each other suggest common cellular and molecular patomechanism and a similar genetic background. In this review, we discuss both similarities and differences of these three humoral immunodeficiencies, focusing on current and novel therapeutic approaches. We summarize immunoglobulin substitution, antibiotic prophylaxis, treatment of autoimmune diseases, and other common complications, i.e. cytopenias, gastrointestinal complications, and granulomatous disease. We discuss novel therapeutic approaches such as allogenic stem cell transplantation and therapies targeting-specific proteins, dependent on the patient's genetic defect. The diversity of possible therapeutics models results from a great heterogeneity of the disease variants, implying the need of personalized medicine approach as a future of primary humoral immunodeficiencies treatment., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Immunology.)

Selective IgA deficiency (SIgAD) is the most common form and common variable immunodeficiency (CVID) is the most symptomatic form of predominant antibody deficiency. Despite differences in the clinical picture, a similar genetic background is suggested. A common feature of both disorders is the occurrence of autoimmune conditions. Regulatory T cells (T regs ) are the major immune cell type that maintains autoimmune tolerance. As the different types of abnormalities of T reg cells have been associated with autoimmune disorders in primary immunodeficiency (PID) patients, in our study we aimed to analyze the gene expression profiles of T reg cells in CVID and SIgAD patients compared to age-matched healthy controls. The transcriptome-wide gene profiling was performed by microarray technology. As a result, we analyzed and visualized gene expression patterns of isolated population of T reg cells. We showed the differences at the gene level between patients with and without autoimmunizations. Our findings suggest that the gene signatures of T reg cells isolated from SIgAD and CVID patients differ from age-matched healthy controls and from each other, presenting transcriptional profiles enriched in innate immune or Th response, respectively. The occurrence of autoimmunity in both types of PID is associated with down-regulation of class I IFNs signaling pathways. In summary, our findings improve our understanding of T reg dysfunctions in patients with common PIDs and associated autoimmunity.

Aims: Tumour necrosis factor α (TNF-α) represents a classical pro-inflammatory cytokine, and its increased levels positively correlate with the severity of many cardiovascular diseases. Surprisingly, some heart failure patients receiving high doses of anti-TNF-α antibodies showed serious health worsening. This work aimed to examine the role of TNF-α signalling on the development and progression of myocarditis and heart-specific autoimmunity., Methods and Results: Mice with genetic deletion of TNF-α (Tnf+/- and Tnf-/-) and littermate controls (Tnf+/+) were used to study myocarditis in the inducible and the transgenic T cell receptor (TCRM) models. Tnf+/- and Tnf-/- mice immunized with α-myosin heavy chain peptide (αMyHC) showed reduced myocarditis incidence, but the susceptible animals developed extensive inflammation in the heart. In the TCRM model, defective TNF-α production was associated with increased mortality at a young age due to cardiomyopathy and cardiac fibrosis. We could confirm that TNF-α as well as the secretome of antigen-activated heart-reactive effector CD4+ T (Teff) cells effectively activated the adhesive properties of cardiac microvascular endothelial cells (cMVECs). Our data suggested that TNF-α produced by endothelial in addition to Teff cells promoted leucocyte adhesion to activated cMVECs. Analysis of CD4+ T lymphocytes from both models of myocarditis showed a strongly increased fraction of Teff cells in hearts, spleens, and in the blood of Tnf+/- and Tnf-/- mice. Indeed, antigen-activated Tnf-/- Teff cells showed prolonged long-term survival and TNF-α cytokine-induced cell death of heart-reactive Teff., Conclusion: TNF-α signalling promotes myocarditis development by activating cardiac endothelial cells. However, in the case of established disease, TNF-α protects from exacerbating cardiac inflammation by inducing activation-induced cell death of heart-reactive Teff. These data might explain the lack of success of standard anti-TNF-α therapy in heart failure patients and open perspectives for T cell-targeted approaches., Competing Interests: Conflict of interest: This manuscript was handled by Consulting Editor Federica Marelli-Berg., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively induces apoptosis of sensitive cancer cells, including colorectal cancer (CRC). Due to its short biological half-life after intravenous administration and related clinical ineffectiveness, novel formulations of TRAIL need to be developed. Here we propose Lactococcus lactis bacteria as a vehicle for local delivery of human soluble TRAIL (hsTRAIL) in CRC. The use of common probiotics targeting guts as carriers for TRAIL could ensure its sustained release at the tumor site and extend the duration of its activity. We have already engineered hsTRAIL-secreting L.lactis bacteria and showed their effectiveness in elimination of human CRC cells in vitro and in vivo in a mouse subcutaneous model. Here, L.lactis (hsTRAIL+) were administered by gastric gavage to SCID mice with orthotopically developed HCT116 tumor in cecum, in monotherapy or in combination with metformin (MetF), already shown to enhance the hsTRAIL anti-tumor activity in subcutaneous CRC model. Oral administration of L.lactis (hsTRAIL+) resulted in significant progression of HCT116 tumors and shortening of the colon crypts. Secretion of hsTRAIL in the colon was accompanied by infiltration of the primary tumor with M2-macrophages, while MetF promoted transient colonization of the gut by L.lactis . Our study indicates that L.lactis bacteria after oral administration enable delivery of biologically active hsTRAIL to colon, however its potential therapeutic effect in CRC treatment is abolished by its pro-tumorigenic signalling, leading to the recruitment of M2-macrophages and tumor growth promotion., (© 2023 Katarzyna Kaczmarek et al., published by Sciendo.)

Transient hypogammaglobulinemia of infancy (THI) is one of the most common forms of hypogammaglobulinemia in the early childhood. THI is usually associated with chronic, recurrent bacterial and viral infections, life-threatening in some cases, yet its pathogenesis is still largely unknown. As our previous findings indicated the possible role of Treg cells in the pathomechanism of THI, the aim of the current study was to investigate gene expression profile of Treg cells isolated from THI patients. The transcriptome-wide gene profiling was performed using microarray technology on THI patients in two time-points: during (THI-1), and in resolution phase (THI-2) of hypogammaglobulinemia. As a result, a total of 1086 genes were differentially expressed in THI-1 patients, when compared to THI-2 as well as control group. Among them, 931 were up- and 155 downregulated, and part of them encodes genes important for Treg lymphocyte biology and function, i.e. transcription factors/cofactors that regulate FOXP3 expression. Thus, we postulate that Treg cells isolated from THI patients during hypogammaglobulinemia display enhanced suppressor transcriptome signature. Treg expression profile of THI children after normalization of Ig levels largely resembles the results obtained in healthy control group, suggesting THI Treg transcriptome seems to return to that observed in healthy children. Taken together, we suggest that THI pathomechanism is associated not only with transiently elevated Treg cell numbers, but also with their enhanced regulatory/inhibitory functions. These findings expand our knowledge of human Treg cells and may be useful for the future diagnosis or management of THI., (© The Author(s) 2023. Published by Oxford University Press on behalf of the British Society for Immunology.)

Psoriatic arthritis (PsA) is a chronic inflammatory disease, characterised by the pathological occurrence of two opposite phenomena-osteoresorption and osteogenesis. Dickkopf-related protein 1 (DKK1) which inhibits the Wingless protein (Wnt) signalling pathway has been shown to be a master regulator of bone remodeling in inflammatory rheumatic diseases. However, the exact relationship between DKK1 serum level and bone remodelling is not clear. The goal of this study is to review state-of-the-art knowledge on the association of serum DKK1 with a bone remodelling in PsA. The MEDLINE-PubMed, EMBASE, Scopus, Web of Science and DOAJ databases were searched for appropriate papers. The English terms: 'DKK1', 'Dickkopf-1' 'Dickkopf related protein 1', 'psoriatic arthritis' and 'PsA' were used for search purposes. Eight original articles and two reviews were identified up to August 2023. In four out of 8 discussed studies DKK1 serum level was higher in PsA patients than in healthy controls [Dalbeth, p < 0.01; Diani, p < 0.001; Chung, p < 0.01; Abd el Hamid, p < 0.001)], it was comparable in another (Daousiss, p = 0.430) and was lower in two (Fassio2017, p < 0.05; Fassio2019, p < 0.05). In one study, the comparative groups included patients with axial spondyloarthritis, where DKK1 serum levels were lower in PsA groups [Jadon, peripheral PsA, p = 0.01]. The true relative serum concentration of DKK1 in PsA, as well as its influence on osteogenesis and osteoresorption, is still equivocal. Further studies on this matter with consistent and stringent methodology are warranted., (© 2023. The Author(s).)

According to the World Health Organization (WHO), air pollution is one of the most serious threats for our planet. Despite a growing public awareness of the harmful effects of air pollution on human health, the specific influence of particulate matter (PM) on human immune cells remains poorly understood. In this study, we investigated the effect of PM on peripheral blood monocytes in vitro. Monocytes from healthy donors (HD) were exposed to two types of PM: NIST (SRM 1648a, standard urban particulate matter from the US National Institute for Standards and Technology) and LAP (SRM 1648a with the organic fraction removed). The exposure to PM-induced mitochondrial ROS production followed by the decrease of mitochondrial membrane potential and activation of apoptotic protease activating factor 1 (Apaf-1), Caspase-9, and Caspase-3, leading to the cleavage of Gasdermin E (GSDME), and initiation of pyroptosis. Further analysis showed a simultaneous PM-dependent activation of inflammasomes, including NLRP3 (nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3) and Caspase-1, followed by cleavage of Gasdermin D (GSDMD) and secretion of IL-1β. These observations suggest that PM-treated monocytes die by pyroptosis activated by two parallel signaling pathways, related to the inorganic and organic PM components. The release of IL-1β and expression of danger-associated molecular patterns (DAMPs) by pyroptotic cells further activated the remnant viable monocytes to produce inflammatory cytokines (TNF-α, IL-6, IL-8) and protected them from death induced by the second challenge with PM.In summary, our report shows that PM exposure significantly impacts monocyte function and induces their death by pyroptosis. Our observations indicate that the composition of PM plays a crucial role in this process-the inorganic fraction of PM is responsible for the induction of the Caspase-3-dependent pyroptotic pathway. At the same time, the canonical inflammasome path is activated by the organic components of PM, including LPS (Lipopolysaccharide/endotoxin). PM-induced pyroptosis of human monocytes. Particulate matter (PM) treatment affects monocytes viability already after 15 min of their exposure to NIST or LAP in vitro. The remnant viable monocytes in response to danger-associated molecular patterns (DAMPs) release pro-inflammatory cytokines and activate Th1 and Th17 cells. The mechanism of PM-induced cell death includes the increase of reactive oxygen species (ROS) production followed by collapse of mitochondrial membrane potential (ΔΨ m ), activation of Apaf-1, Caspase-9 and Caspase-3, leading to activation of Caspase-3-dependent pyroptotic pathway, where Caspase-3 cleaves Gasdermin E (GSDME) to produce a N-terminal fragment responsible for the switch from apoptosis to pyroptosis. At the same time, PM activates the canonical inflammasome pathway, where activated Caspase-1 cleaves the cytosolic Gasdermin D (GSDMD) to produce N-terminal domain allowing IL-1β secretion. As a result, PM-treated monocytes die by pyroptosis activated by two parallel pathways-Caspase-3-dependent pathway related to the inorganic fraction of PM and the canonical inflammasome pathway dependent on the organic components of PM., (© 2023. BioMed Central Ltd., part of Springer Nature.)

During tumor progression, monocytes circulating in the blood or infiltrating tissue may be exposed to tumor-derived extracellular vesicles (TEVs). The first stage of such interactions involves binding of TEVs to the surface of monocytes, followed by their internalization. The present study examines the role of CD44 molecules in the interactions between monocytes and EVs derived from colon cancer cell lines (HCT116 and SW1116). The efficiency of the attachment and engulfment of TEVs by monocytes is linked to the number of TEVs and time of exposure/interaction. The two investigated TEVs, TEVs HCT116 and TEVs SW1116 , originating from HCT116 and SW1116 cells, respectively, differ in hyaluronan (HA) cargo, which reflects HA secretion by parental cancer cells. HA-rich TEVs HCT116 are internalized more effectively in comparison with HA-low TEVs SW1116 . Blocking of CD44 molecules on monocytes by anti-CD44 monoclonal antibody significantly decreased the engulfment of TEVs HCT116 but not that of TEVs SW1116 after 30 min contact, suggesting the involvement of the HA-CD44 axis. The three subsets of monocytes, classical, intermediate and non-classical, characterized by gradual changes in the expression of CD14 and CD16 markers, also differ in the expression of CD44. The highest expression of CD44 molecules was observed in the intermediate monocyte subset. Blocking of CD44 molecules decreased the internalization of HA-rich TEVs in all three subsets, which is associated with CD44 expression level. It was hypothesized that HA carried by TEVs, potentially as a component of the 'corona' coating, may facilitate the interaction between subsets of monocytes and TEVs, which may influence the fate of TEVs (such as the rate of TEVs adhesion and engulfment) and change monocyte activity., Competing Interests: The authors declare that they have no competing interests., (Copyright: © Babula et al.)

Introduction: Natural killer (NK) cells plays a pivotal role in the control of viral infections, and their function depend on the balance between their activating and inhibitory receptors. The immune dysregulation observed in COVID-19 patients was previously associated with downregulation of NK cell numbers and function, yet the mechanism of inhibition of NK cell functions and the interplay between infected cells and NK cells remain largely unknown., Methods: In this study we show that SARS-CoV-2 infection of airway epithelial cells can directly influence NK cell phenotype and functions in the infection microenvironment. NK cells were co-cultured with SARS-CoV-2 infected epithelial cells, in a direct contact with A549 ACE2/TMPRSS2 cell line or in a microenvironment of the infection in a 3D ex vivo human airway epithelium (HAE) model and NK cell surface expression of a set of most important receptors (CD16, NKG2D, NKp46, DNAM-1, NKG2C, CD161, NKG2A, TIM-3, TIGIT, and PD-1) was analyzed., Results: We observed a selective, in both utilized experimental models, significant downregulation the proportion of CD161 (NKR-P1A or KLRB1) expressing NK cells, and its expression level, which was followed by a significant impairment of NK cells cytotoxicity level against K562 cells. What is more, we confirmed that SARS-CoV-2 infection upregulates the expression of the ligand for CD161 receptor, lectin-like transcript 1 (LLT1, CLEC2D or OCIL), on infected epithelial cells. LLT1 protein can be also detected not only in supernatants of SARS-CoV-2 infected A549 ACE2/TMPRSS2 cells and HAE basolateral medium, but also in serum of COVID-19 patients. Finally, we proved that soluble LLT1 protein treatment of NK cells significantly reduces i) the proportion of CD161+ NK cells, ii) the ability of NK cells to control SARS-CoV-2 infection in A549 ACE2/TMPRSS2 cells and iii) the production of granzyme B by NK cells and their cytotoxicity capacity, yet not degranulation level., Conclusion: We propose a novel mechanism of SARS-CoV-2 inhibition of NK cell functions via activation of the LLT1-CD161 axis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Lenart, Górecka, Bochenek, Barreto-Duran, Szczepański, Gałuszka-Bulaga, Mazur-Panasiuk, Węglarczyk, Siwiec-Koźlik, Korkosz, Łabaj, Baj-Krzyworzeka, Siedlar and Pyrc.)

Spondyloarthropathies (SpA) are a family of rheumatic disorders that could be divided into axial (axSpA) and peripheral (perSpA) sub-forms depending on the disease clinical presentation. The chronic inflammation is believed to be driven by innate immune cells such as monocytes, rather than self-reactive cells of adaptive immune system. The aim of the study was to investigate the micro-RNA (miRNA) profiles in monocyte subpopulations (classical, intermediate and non-classical subpopulations) acquired from SpA patients or healthy individuals in search for prospective disease specific and/or disease subtype differentiating miRNA markers. Several SpA-specific and axSpA/perSpA differentiating miRNAs have been identified that appear to be characteristic for specific monocyte subpopulation. For classical monocytes, upregulation of miR-567 and miR-943 was found to be SpA-specific, whereas downregulation of miR-1262 could serve as axSpA-differentiating, and the expression pattern of miR-23a, miR-34c, mi-591 and miR-630 as perSpA-differentiating markers. For intermediate monocytes, expression levels of miR-103, miR-125b, miR-140, miR-374, miR-376c and miR-1249 could be used to distinguish SpA patients from healthy donors, whereas the expression pattern of miR-155 was identified as characteristic for perSpA. For non-classical monocytes, differential expression of miR-195 was recognized as general SpA indicator, while upregulation of miR-454 and miR-487b could serve as axSpA-differentiating, and miR-1291 as perSpA-differentiating markers. Our data indicate for the first time that in different SpA subtypes, monocyte subpopulations bear disease-specific miRNA signatures that could be relevant for SpA diagnosis/differentiation process and may help to understand SpA etiopathology in the context of already known functions of monocyte subpopulations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Stec, Czepiel, Lenart, Piestrzyńska-Kajtoch, Plewka, Bieniek, Węglarczyk, Szatanek, Rutkowska-Zapała, Guła, Kluczewska, Baran, Korkosz and Siedlar.)

Background: Metformin is an inhibitor of oxidative phosphorylation that displays an array of anticancer activities. The interference of metformin with the activity of multi-drug resistance systems in cancer cells has been reported. However, the consequences of the acquired chemoresistance for the adaptative responses of cancer cells to metformin-induced stress and for their phenotypic evolution remain unaddressed., Methods: Using a range of phenotypic and metabolic assays, we assessed the sensitivity of human prostate cancer PC-3 and DU145 cells, and their drug-resistant lineages (PC-3&#95;DCX20 and DU145&#95;DCX20), to combined docetaxel/metformin stress. Their adaptation responses have been assessed, in particular the shifts in their metabolic profile and invasiveness., Results: Metformin increased the sensitivity of PC-3 wild-type (WT) cells to docetaxel, as illustrated by the attenuation of their motility, proliferation, and viability after the combined drug application. These effects correlated with the accumulation of energy carriers (NAD(P)H and ATP) and with the inactivation of ABC drug transporters in docetaxel/metformin-treated PC-3 WT cells. Both PC-3 WT and PC-3&#95;DCX20 reacted to metformin with the Warburg effect; however, PC-3&#95;DCX20 cells were considerably less susceptible to the cytostatic/misbalancing effects of metformin. Concomitantly, an epithelial-mesenchymal transition and Cx43 upregulation was seen in these cells, but not in other more docetaxel/metformin-sensitive DU145&#95;DCX20 populations. Stronger cytostatic effects of the combined fenofibrate/docetaxel treatment confirmed that the fine-tuning of the balance between energy supply and expenditure determines cellular welfare under metabolic stress., Conclusions: Collectively, our data identify the mechanisms that underlie the limited potential of metformin for the chemotherapy of drug-resistant tumors. Metformin can enhance the sensitivity of cancer cells to chemotherapy by inducing their metabolic decoupling/imbalance. However, the acquired chemoresistance of cancer cells impairs this effect, facilitates cellular adaptation to metabolic stress, and prompts the invasive front formation., (© 2022. The Author(s).)