Search Results (30)

Background: The STING (Stimulator of Interferon Genes) pathway plays a vital role in the body’s innate immune defense system, primarily involved in DNA sensing and type I interferon production. While STING is well-established in various immune cells, its role in natural killer (NK) cells, particularly within the context of liver fibrosis, remains inadequately explored. Aim: The current study investigates the relationship between STING expression, NK cell activity, and insulin receptor (IR) signaling in patients with metabolic dysfunction-associated steatohepatitis (MASH). Methods: Peripheral NK cells were isolated from healthy controls and MASH patients with varying stages of liver fibrosis (early: F1/F2; advanced: F3/F4). The expressions of STING, IR, NK cell activation markers (CD107a, NKp46), and NK cell inhibitory markers (LAIR-1, Siglec-7) were assessed using flow cytometry. NK cell cytotoxicity against primary hepatic stellate cells (pHSCs) was evaluated through apoptosis assays. STING agonists (2′3′-cGAMP and DMXAA) were used to stimulate NK cells, and their effects on STING expression, NK cell activation, and cytotoxicity were measured. Additionally, the impact of insulin signaling on STING expression and NK cell function was examined. Results: Our results demonstrate that STING expression in NK cells correlates with disease severity in liver fibrosis. NK cells from MASH patients with advanced fibrosis (F3/F4) showed inhibited STING protein levels that were statistically comparable to healthy NK cells and accompanied by impaired cytotoxicity and decreased IFN-γ production. In contrast, NK cells from early fibrosis (F1/F2) exhibited higher STING expression and better functional activity. STING agonist treatment (2′3′-cGAMP) restored STING expression and enhanced NK cell activity across all fibrosis stages. Furthermore, insulin treatment and combined insulin and 2′3′-cGAMP treatment synergistically upregulated both IR and STING expressions, leading to improved NK cell function and increased cytotoxicity, particularly in advanced fibrosis. Conclusion: Our results highlight the potential of targeting STING and insulin signaling pathways as a therapeutic approach in restoring NK cell function and enhance immune surveillance in liver fibrosis. Full article

Background/Objectives: Metabolic dysfunction-associated steatohepatitis (MASH), characterized by liver inflammation, fibrosis, and fat accumulation, can develop into cirrhosis and liver cancer. Despite its increasing prevalence worldwide, there are few established therapies for advanced MASH. We previously demonstrated that stem cells from human exfoliated deciduous teeth-conditioned media (SHED-CM) exerted therapeutic effects in a MASH mouse model. The gut–liver axis is thought to be associated with liver disease progression, and soluble Siglec-9 (sSiglec-9), an immunoinhibitory receptor, is a key protein in SHED-CM that induces anti-inflammatory macrophages and has intestinal epithelial protective effects. Therefore, we evaluated sSiglec-9’s role in intestinal barrier protection in MASH mice. Methods: We evaluated sSiglec-9 effects on intestinal barrier function using in vitro Caco-2 cell monolayers injured by TNF-α and IFN-γ. For the MASH mouse model, male C57BL/6J mice were given a Western diet and high-sugar solution orally; to induce liver injury, CCl4 was intraperitoneally administered for 12 weeks. Mice were treated weekly with 10 ng/g sSiglec-9 or vehicle. Intestinal permeability was assessed by blood 4 kDa FITC-dextran concentration, and intestinal transcriptomes and liver histology were analyzed. Results: sSiglec-9 decreased intestinal permeability and liver inflammation in MASH mice. sSiglec-9 and SHED-CM reduced 4 kDa FITC-dextran permeability in injured Caco-2 cells, and sSiglec-9 significantly reduced intestinal permeability and modulated expression of 34 intestinal genes. The NAFLD Activity Score indicated significantly reduced inflammation following sSiglec-9 treatment. Conclusions: sSiglec-9 may protect intestinal barrier function by mitigating mucosal inflammation. sSiglec-9 treatment may represent a novel therapeutic approach for MASH via gut–liver axis modulation. Full article

Background: The C1858T PTPN22 variant is strongly associated with type 1 diabetes and autoimmune thyroid disease. Current treatment is substitutive hormonal administration, which does not target the disease pathogenetic mechanism. We previously implemented a novel immunotherapy, employing siRNA directed against the C1858T variant of PTPN22 delivered via functionalized lipoplexes, in order to halt autoimmune disease progression. Objectives: The objective of this study was to optimize lipoplex formulations functionalized with F9-PEG (a Siglec-10’s ligand) to facilitate targeted delivery by investigating their physical and chemical properties to warrant the best performance in in vivo studies. Methods: The effectiveness of siRNA liposome binding was evaluated by varying the relative lipid/siRNA charge ratio and analyzing the stability of the different formulations with respect to the methods of F9-PEG addition and ATTO740 fluorescent labeling by electrophoresis, dynamic and dielectrophoretic light scattering (DLS and DELS), and high-performance liquid chromatography (HPLC). Results: The optimal charge ratio of +2/−1 (lipid/siRNA) ensured a greater stability of lipoplexes and complete complexation of siRNA. Stability was improved by selecting a protocol of preparation that envisages functionalization with F9-PEG and the addition of ATTO740 lipid in the lipid film preparation step. HPLC confirmed the integrity of siRNA after preparation. Conclusions: The results of this study lead to formulations of F9-PEG lipoplexes with optimal properties that could be used for biodistribution and safety/efficacy studies in mice. Lipoplexes functionalized with F9-PEG could therefore represent a promising personalized nanotherapeutic platform for targeted siRNA delivery in endocrine C1858T patients. Full article

Immune checkpoint inhibitors like programmed cell death 1 (PD-1) antibodies have revolutionized cancer treatment, but patient response rates remain limited. Sialic acid-binding Ig-like lectin 15 (Siglec-15) has emerged as a promising new immune checkpoint target. Through phage display technology using a Bactrian camel immunized with recombinant human Siglec-15, we generated six anti-Siglec-15 camelid nanobodies and constructed chimeric heavy-chain antibodies by fusing the VHH domains with human IgG-Fc. Following expression in HEK293-F cells and purification, three antibodies (S1, S5, S6) demonstrated specific binding to both human and murine Siglec-15 in ELISA and biolayer interferometry assays. In a xenograft model established by subcutaneous inoculation of NCI-H157-S15 cells into BALB/c nude mice, these antibodies showed distinct tumor targeting and significant blockade of Siglec-15 interactions with CD44, MAG, sialyl-Tn, and LRR4C ligands. All three antibodies exhibited anti-tumor effects, with S1 showing the most potent activity. S1-treated mice had significantly smaller tumor volumes and weights compared to controls. The S1, S5, and S6 treatment groups showed enhanced anti-tumor immunity, with reduced TGF-β, IL-6, and IL-10 levels. Notably, S1 treatment significantly increased tumor-associated macrophages in tumor tissues (p < 0.05). In conclusion, S1 exhibits remarkable anti-tumor activity and has the potential to be developed as a cancer immunotherapy targeting Siglec-15. Full article

Neutrophil extracellular traps (NETs) play a key role in the development of bronchopulmonary dysplasia (BPD), yet their molecular mechanisms in contributing to BPD remain unexplored. Using the GSE32472 dataset, which includes 100 blood samples from postnatal day 28, we conducted comprehensive bioinformatics analyses to identify differentially expressed genes (DEGs) and construct gene modules. We identified 86 DEGs, which were enriched in immune and inflammatory pathways, including NET formation. Weighted gene co-expression network analysis (WGCNA) revealed a key gene module associated with BPD. By intersecting 69 NET-related genes (NRGs), 149 module genes, and 86 DEGs, we identified 12 differentially expressed NET-related genes (DENRGs). Immune infiltration analysis revealed an increase in neutrophils, dendritic cells, and macrophages in BPD patients. Machine learning models (LASSO, SVM-RFE, and RF) identified 5 upregulated biomarkers—MMP9, Siglec-5, DYSF, MGAM, and S100A12—showing potential as diagnostic biomarkers for BPD. Validation using nomogram, ROC curves, and qRT-PCR confirmed the diagnostic accuracy of these biomarkers. Clinical data analysis showed that Siglec-5 was most strongly correlated with BPD severity, while DYSF correlated with the grade of retinopathy of prematurity (ROP) and its laser treatment. Clustering analysis revealed two distinct BPD subtypes with different immune microenvironment profiles. Drug–gene interaction analysis identified potential inhibitors targeting MGAM and MMP9. In conclusion, the study identifies five NET-related biomarkers as reliable diagnostic tools for BPD, with their upregulation and association with disease severity and complications, such as ROP, highlighting their clinical relevance and potential for advancing BPD diagnostics and treatment. Full article

Gastric cancer (GC) ranks as the fifth most prevalent malignant neoplasm globally, with an increased death rate despite recent advancements in research and therapeutic options. Different molecular subtypes of GC have distinct interactions with the immune system, impacting the tumor microenvironment (TME), prognosis, and reaction to immunotherapy. Tumor-infiltrating lymphocytes (TILs) in the TME are crucial for preventing tumor growth and metastasis, as evidenced by research showing that patients with GC who have a significant density of TILs have better survival rates. But cancer cells have evolved a variety of mechanisms to evade immune surveillance, both sialic acid-binding immunoglobulin-like lectin 15 (Siglec-15) and Programmed Death-Ligand 1 (PD-L1) playing a pivotal role in the development of an immunosuppressive TME. They prevent T cell activation and proliferation resulting in a decrease in the immune system’s capacity to recognize and eliminate malignant cells. These immune checkpoint molecules function via different but complementary mechanisms, the expression of Siglec-15 being mutually exclusive with PD-L1 and, therefore, providing a different therapeutic approach. The review explores how TILs affect tumor growth and patient outcomes in GC, with particular emphasis on their interactions within the TME and potential targeting of the PD-L1 and Siglec-15 pathways for immunotherapy. Full article

Background/Objectives: The global SARS-CoV-2 outbreak has escalated into a critical public health emergency, with the spike glycoprotein S1 subunit of SARS-CoV-2 (spike-S1) linked to inflammation in lung tissue and immune cells. Luteolin, a flavone with anti-inflammatory properties, shows promise, but research on its effectiveness against long-COVID-related inflammation and spike protein-induced responses remains limited. This study aims to elucidate the underlying mechanisms of inflammation in THP-1 cells induced by the spike-S1. Additionally, it seeks to assess the potential of luteolin in mitigating inflammatory responses induced by the spike-S1 in a THP-1 macrophage model. Methods: The gene expression profiles of spike-S1 in THP-1 cells were analyzed by transcriptome sequencing. The inhibitory effect of luteolin on ER stress and inflammation in spike-S1-induced THP-1 cells was investigated using Western blotting, RT-PCR, and ELISA. Results: The candidate genes (CAMK2A, SIGLEC7, PPARGC1B, SEC22B, USP28, IER2, and TIRAP) were upregulated in the spike-S1-induced THP-1 group compared to the control group. Among these, calcium/calmodulin-dependent protein kinase II alpha (CAMK2A) was identified as the most promising molecule in spike-S1-induced THP-1 cells. Our results indicate that the spike S1 significantly increased the expression of ER-stress markers at both gene and protein levels. Luteolin significantly reduced ER stress by decreasing the expression of ER-stress marker genes and ER-stress marker proteins (p < 0.01). Additionally, luteolin exhibited anti-inflammatory properties upon spike S1-induction in THP-1 cells by significantly suppressing IL-6, IL-8, and IL-1β cytokine secretion in a dose-dependent manner (p < 0.05). Furthermore, our results revealed that luteolin exhibited the downregulation of the MAPK pathway, as evidenced by modulating the phosphorylation of p-ERK1/2, p-JNK and p-p38 proteins (p < 0.05). Conclusions: The results from this study elucidate the mechanisms by which the spike S1 induces inflammation in THP-1 cells and supports the use of naturally occurring bioactive compounds, like luteolin, against inflammation-related SARS-CoV-2 infection. Full article

A murine colorectal carcinoma (CRC) model was established. CT26 colon carcinoma cells were injected into BALB/c mice’s spleen to study the primary tumor and the mechanisms of cell spread of colon cancer to the liver. The CRC was verified by the immunohistochemistry of Pan Cytokeratin and Vimentin expression. Immunophenotyping of leukocytes isolated from CRC-bearing BALB/c mice or healthy controls, such as CD19+ B cells, CD11+ myeloid cells, and CD3+ T cells, was carried out using fluorochrome-labeled lectins. The binding of six lectins to white blood cells, such as galectin-1 (Gal1), siglec-1 (Sig1), Sambucus nigra lectin (SNA), Aleuria aurantia lectin (AAL), Phytolacca americana lectin (PWM), and galectin-3 (Gal3), was assayed. Flow cytometric analysis of the splenocytes revealed the increased binding of SNA, and AAL to CD3 + T cells and CD11b myeloid cells; and increased siglec-1 and AAL binding to CD19 B cells of the tumor-bearing mice. The whole proteomic analysis of the established CRC-bearing liver and spleen versus healthy tissues identified differentially expressed proteins, characteristic of the primary or secondary CRC tissues. KEGG Gene Ontology bioinformatic analysis delineated the established murine CRC characteristic protein interaction networks, biological pathways, and cellular processes involved in CRC. Galectin-1 and S100A4 were identified as upregulated proteins in the primary and secondary CT26 tumor tissues, and these were previously reported to contribute to the poor prognosis of CRC patients. Modelling the development of liver colonization of CRC by the injection of CT26 cells into the spleen may facilitate the understanding of carcinogenesis in human CRC and contribute to the development of novel therapeutic strategies. Full article

Siglecs play a key role in mediating cell–cell interactions via the recognition of different sialylated glycoconjugates, including tumor-associated MUC1, which can lead to the activation or inhibition of the immune response. The activation occurs through the signaling of Siglecs with the cytoplasmic immunoreceptor tyrosine-based activation motif (ITAM)-containing proteins, while the inhibition signal is a result of the interaction of intracellular immunoreceptor tyrosine-based inhibition motif (ITIM)-bearing receptors. The interaction of tumor-associated MUC1 sialylated glycans with Siglecs via ITIM motifs decreases antitumor immunity. Consequently, these interactions are expected to play a key role in tumor evasion. Efforts to modulate the response of immune cells by blocking the immune-suppressive effects of inhibitory Siglecs, driving immune-activating Siglecs, and/or altering the synthesis and expression of the sialic acid glycocalyx are new therapeutic strategies deserving further investigation. We will highlight the role of Siglec’s family receptors in immune evasion through interactions with glycan ligands in their natural context, presented on the protein such as MUC1, factors affecting their fine binding specificities, such as the role of multivalency either at the ligand or receptor side, their spatial organization, and finally the current and future therapeutic interventions targeting the Siglec–sialylated MUC1 immune axis in cancer. Full article

Immunotherapy is one of the leading systemic therapies in non-small cell cancer (NSCLC) patients, but it is not effective in an important proportion of them due to primary or secondary resistance mechanisms. Clinicians do not have the tools to predict immunotherapy resistance, and thus, many patients still fail initial treatment. One of the scientific concepts to avoid resistance and/or offer the patient effective salvage second-line treatment is the dual immunologic checkpoint blockade. We aimed to review published and available data on combination immunotherapy in terms of mechanisms, efficacy, and safety data on many different dual blockades. We discussed the potential of combined CTLA-4 (Cytotoxic T Lymphocyte Antigen 4), PD-1 (Programmed Death 1) or PD-L1, TIGIT, LAG-3, TIM-3, macrophage leukocyte immunoglobulin-like receptor B2 (LILRB2/ILT4), S15-mediated immune suppression (SIGLEC-15), CD137, ICOS, and OX40 inhibitors in NSCLC treatment. Full article

Since the role of sialome–Siglec axis has been described as a regulatory checkpoint of immune homeostasis, the promotion of stimulatory or inhibitory Siglec-related mechanisms is crucial in cancer progression and therapy. Here, we investigated the effect of tamoxifen on the sialic acid–Siglec interplay and its significance in immune conversion in breast cancer. To mimic the tumour microenvironment, we used oestrogen-dependent or oestrogen-independent breast cancer cells/THP-1 monocytes transwell co-cultures exposed to tamoxifen and/or β-estradiol. We found changes in the cytokine profiles accompanied by immune phenotype switching, as measured by the expression of arginase-1. The immunomodulatory effects of tamoxifen in THP-1 cells occurred with the altered SIGLEC5 and SIGLEC14 genes and the expression of their products, as confirmed by RT-PCR and flow cytometry. Additionally, exposure to tamoxifen increased the binding of Siglec-5 and Siglec-14 fusion proteins to breast cancer cells; however, these effects appeared to be unassociated with oestrogen dependency. Our results suggest that tamoxifen-induced alterations in the immune activity of breast cancer reflect a crosstalk between the Siglec-expressing cells and the tumour’s sialome. Given the distribution of Siglec-5/14, the expression profile of inhibitory and activatory Siglecs in breast cancer patients may be useful in the verification of therapeutic strategies and predicting the tumour’s behaviour and the patient’s overall survival. Full article

The correct phagocytic activity of microglia is a prerequisite for maintaining homeostasis in the brain. In the analysis of mechanisms regulating microglial phagocytosis, we focused on the bromodomain and extraterminal domain (BET) proteins: Brd2, Brd3, and Brd4, the acetylation code readers that control gene expression in cooperation with transcription factors. We used pharmacological (JQ1) and genetic (siRNA) inhibition of BET proteins in murine microglial cell line BV2. Inhibition of BET proteins reduced the phagocytic activity of BV2, as determined by using a fluorescent microspheres-based assay and fluorescently labelled amyloid-beta peptides. Gene silencing experiments demonstrated that all brain-existing BET isoforms control phagocytosis in microglia. From a set of 84 phagocytosis-related genes, we have found the attenuation of the expression of 14: Siglec1, Sirpb1a, Cd36, Clec7a, Itgam, Tlr3, Fcgr1, Cd14, Marco, Pld1, Fcgr2b, Anxa1, Tnf, Nod1, upon BET inhibition. Further analysis of the mRNA level of other phagocytosis-related genes which were involved in the pathomechanism of Alzheimer’s disease demonstrated that JQ1 significantly reduced the expression of Cd33, Trem2, and Zyx. Our results indicate the important role of BET proteins in controlling microglial phagocytosis; therefore, targeting BET may be the efficient method of modulating microglial activity. Full article

Fulminant myocarditis (FM) is the severest type of myocarditis and requires timely diagnosis and treatment. However, effective biomarkers for early diagnosis of FM are limited. First, 12 common inflammatory cytokines levels in the plasma of patients with FM were measured using human cytokine 12-Plex assay. Then, enzyme-linked immunosorbent assay (ELISA) was used to detect the plasma levels of another eight cytokines that we previously reported on. Moreover, a Spearman correlation test was employed to investigate the correlations between the plasma cytokine levels and the clinical parameters of patients with FM. Finally, receiver operating characteristic (ROC) curve analyses were performed to assess the diagnostic performance of plasma cytokine levels for the detection of FM. Five of the twelve common inflammation cytokines were significantly altered in patients with FM, but none of them was correlated with the severity of FM. Six of the eight significantly changed cytokines that we previously reported on were validated by ELISA. Among these, sST2, Siglec-5, and CD163 were negatively correlated with ejection fraction values. Furthermore, plasma Siglec-5 and CD163 levels were found to be associated with the severity of FM. Finally, both plasma Siglec-5 and CD163 showed outstanding diagnostic performance for FM. The current study identified plasma Siglec-5 and CD163 as valuable novel biomarkers for the early diagnosis of FM. Full article

Genome-wide association studies showed the relationship of NIN, ABHD12B, WHAMM, AP3B2, and SIGLEC5 with chronic periodontitis. The study’s objective was to investigate different molecular patterns and evolutionary forces acting on the mentioned genes. The investigation of molecular patterns encompasses the study of compositional parameters, expression profile, physical properties of genes, codon preferences, degree of codon bias, determination of the most influential codons, and assessment of actions of evolutionary forces, such as mutations and natural selection. The overall compositional analysis revealed the dominance of A and G nucleotides compared to T and C. A relatively low codon usage bias is observed. The CTG codon is the most overused codon, followed by TCC. The genes, AP3B2 and SIGLEC5, preferred GC-ending codons, while NIN, ABHD12B, and WHAMM preferred AT-ending codons. The presence of directional mutational force and natural selection was found to operate codon usage in genes envisaged, and selective forces were dominant over mutational forces. Apart from mutation and selection forces, compositional constraints also played imperative roles. The study enriched our knowledge of specific molecular patterns associated with the set of genes significantly associated with chronic periodontitis. Further studies are warranted to identify more genetic signatures associated with the disease. Full article

The main features of a giant cell tumor of bone (GCTB) are frequent recurrence and aggressive osteolysis, which leads to a poor prognosis in patients. Although the treatment methods for a GCTB, such as scraping and resection, effectively inhibit the disease, the tendency toward malignant transformation remains. Therefore, it is important to identify new treatment methods for a GCTB. In this study, we first found high Siglec-15 expression in GCTB tissues, which was significantly associated with Campanacci staging and tumor recurrence. In Spearman’s analysis, Siglec-15 expression was significantly correlated with Ki-67 levels in tumor tissues. In vitro, the mRNA and protein levels of Siglec-15 were high in GCTB stromal cells (Hs737. T), and Siglec-15 knockdown inhibited the biological characteristics of GCTB stromal cells. The RNA sequencing results enabled a prediction of the downstream genes by using the Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and MCODE analyses, and the findings showed that CXCL8 was significantly regulated by Siglec-15 and might be a promising downstream target gene of Siglec-15. Therefore, Siglec-15 may be a potential immunotherapy target for a GCTB. Full article