Oncostatin M induces dendritic cell maturation and Th1 polarization

Myeloid Cells in Abdominal Aortic Aneurysm

PURPOSE OF REVIEW

Abdominal aortic aneurysm (AAA) is a life-threatening vascular disorder with high mortality upon rupture, yet effective pharmacotherapy remains lacking. This review synthesizes the pivotal roles of myeloid cells-key mediators of aortic inflammation and remodeling-in AAA pathogenesis, highlighting their therapeutic targeting potential.

RECENT FINDINGS

Single-cell RNA sequencing has revealed myeloid diversity in AAA. Among these myeloid populations, macrophages (including interferon-responsive monocytes, pro- and anti-inflammatory subsets, and reparative populations) emerge as central regulators of AAA pathogenesis, influencing disease initiation, progression, and tissue repair processes. Neutrophils promote vascular injury via neutrophil extracellular traps, while dendritic cells bridge innate-adaptive immunity. Eosinophils and myeloid-derived suppressor cells exhibited protective effects by immunoregulation. Mechanistic studies identified transcriptional, metabolic, and epigenetic regulators of myeloid plasticity. Clonal hematopoiesis and trained immunity may serve as potential novel mechanisms of myeloid cells involved in AAA. These mechanistic insights have inspired therapeutic innovation, with nanoparticle-targeted myeloid cell therapies showing promising immunomodulatory effects in mitigating AAA progression. Myeloid cells play a pivotal role in AAA pathogenesis by driving inflammatory responses, extracellular matrix degradation, and maladaptive vascular remodeling. Their functional heterogeneity, encompassing both destructive and protective subsets, highlights the need for precisely targeted therapeutic approaches. While single-cell technologies have significantly advanced our understanding of myeloid diversity, clinical translation remains challenged by microenvironmental crosstalk and potential off-target effects. Future research should prioritize: (1) spatial multi-omics characterization of myeloid-vascular interactions, (2) development of precision therapies targeting clonal hematopoiesis-driven subpopulations, and (3) combinatorial strategies to reprogram pathogenic myeloid phenotypes. Addressing these critical gaps may lead to transformative therapies for aneurysm stabilization, ultimately fulfilling the urgent unmet needs in AAA clinical management.

Single-Cell RNA Sequencing Deconstructs the Distribution of Immune Cells Within Abdominal Aortic Aneurysms in Mice

BACKGROUND

Inflammation is a key component in the development of abdominal aortic aneurysm (AAA), yet insights into the roles of immune cells and their interactions in this process are limited.

METHODS

Using single-cell RNA transcriptomic analysis, we deconstructed the CD45+ cell population in elastase-induced murine AAA at the single-cell level. We isolated each group of immune cells from murine AAA tissue at different time points and divided them into several subtypes, listed the remarkable differentially expressed genes, explored the developmental trajectories of immune cells, and demonstrated the interactions among them.

RESULTS

Our findings reveal significant differences in several immune cell subsets, including macrophages, dendritic cells, and T cells, within the AAA microenvironment compared with the normal aorta. Especially, conventional dendritic cell type 1 exclusively existed in the AAA tissue rather than the normal aortas. Via CellChat analysis, we identified several intercellular communication pathways like visfatin, which targets monocyte differentiation and neutrophil extracellular trap-mediated interaction between neutrophils and dendritic cells, which might contribute to AAA development. Some of these pathways were validated in human AAA.

CONCLUSIONS

Despite the absence of external pathogenic stimuli, AAA tissues develop a complex inflammatory microenvironment involving numerous immune cells. In-depth studies of the inflammatory network shall provide new strategies for patients with AAA.

The role of interleukin-6 in the development of cardiovascular diseases: A review

Currently, the search and study of new biological markers that can provide early diagnosis of cardiovascular diseases, serve as a laboratory tool for assessing the effectiveness of treatment, or be used as prognostic markers and risk stratification criteria is ongoing. Our literature review indicates the potentially important diagnostic and prognostic value of assessing members of the interleukin-6 family. It is expected that further scientific and clinical studies will demonstrate the possibility of using members of the interleukin-6 family as an additional laboratory tool for the diagnosis, risk stratification and prediction of cardiovascular events in cardiac patients. It is necessary to evaluate in detail the possibilities of blockade of these interleukin-6 molecules in patients with cardiovascular diseases in vitro and in vivo.

The Role of Interleukin-6 Family Members in Cardiovascular Diseases

Cardiovascular disease is one of the main causes of human mortality. Cytokines play crucial roles in the development of cardiovascular disease. Interleukin (IL)-6 family members are a series of cytokines, including IL-6, IL-11, IL-30, IL-31, OSM, LIF, CNTF, CT-1, CT-2, and CLC, that regulate multiple biological effects. Experimental and clinical evidence shows that IL-6 family members are closely related to cardiovascular diseases such as atherosclerosis, hypertension, aortic dissection, cardiac fibrosis, and cardiomyopathy. This review mainly discusses the role of IL-6 family members in cardiovascular disease for the sake of identifying possible intervention targets for cardiovascular disease prevention and treatment.

Microplastic consumption induces inflammatory signatures in the colon and prolongs a viral arthritis

Global microplastic (MP) contamination and the effects on the environment are well described. However, the potential for MP consumption to affect human health remains controversial. Mice consuming ≈80 μg/kg/day of 1 μm polystyrene MPs via their drinking water showed no weight loss, nor were MPs detected in internal organs. The microbiome was also not significantly changed. MP consumption did lead to small transcriptional changes in the colon suggesting plasma membrane perturbations and mild inflammation. Mice were challenged with the arthritogenic chikungunya virus, with MP consumption leading to a significantly prolonged arthritic foot swelling that was associated with elevated Th1, NK cell and neutrophil signatures. Immunohistochemistry also showed a significant increase in the ratio of neutrophils to monocyte/macrophages. The picture that emerges is reminiscent of enteropathic arthritis, whereby perturbations in the colon are thought to activate innate lymphoid cells that can inter alia migrate to joint tissues to promote inflammation.

Rheumatoid arthritis synovial microenvironment induces metabolic and functional adaptations in dendritic cells

Rheumatoid arthritis (RA) is a chronic autoimmune disease which causes degradation of cartilage and bone. It is well appreciated that the pathogenic hallmark of RA is the mass influx of inflammatory cells into the joint. However, the role that dendritic cells (DC) may play in this inflammatory milieu is still relatively unexplored. Moreover, the contribution this unique synovial microenvironment has on DC maturation is still unknown. Using monocyte-derived DC (MoDC), we established an in-vitro model to recapitulate the synovial microenvironment to explore DC maturation. MoDC treated with conditioned media from ex-vivo synovial tissue biopsy cultures [explant-conditioned media (ECM)] have increased expression of proinflammatory cytokines, chemokines and adhesion molecules. ECM DC have increased expression of CD83 and CC-chemokine receptor (CCR)7 and decreased expression of CCR5 and phagocytic capacity, suggestive of heightened DC maturation. ECM-induced maturation is concomitant with altered cellular bioenergetics, whereby increased expression of glycolytic genes and increased glucose uptake are observed in ECM DC. Collectively, this results in a metabolic shift in DC metabolism in favour of glycolysis. These adaptations are in-part mediated via signal transducer and activator of transcription-3 (STAT-3), as demonstrated by decreased expression of proinflammatory cytokines and glycolytic genes in ECM DC in response to STAT-3 inhibition. Finally, to translate these data to a more in-vivo clinically relevant setting, RNA-seq was performed on RA synovial fluid and peripheral blood. We identified enhanced expression of a number of glycolytic genes in synovial CD1c+ DC compared to CD1c+ DC in circulation. Collectively, our data suggest that the synovial microenvironment in RA contributes to DC maturation and metabolic reprogramming.

Mechanism of prostaglandin E2-induced transcriptional up-regulation of Oncostatin-M by CREB and Sp1

Oncostatin-M (OSM) is a pleotropic cytokine belonging to the interleukin-6 family. Differential expression of OSM in response to varying stimuli and exhibiting repertoire of functions in different cells renders it challenging to study the mechanism of its expression. Prostaglandin E₂ (PGE₂) transcriptionally increased osm levels. In silico studies of ∼1 kb upstream of osm promoter region yielded the presence of CRE (cyclic AMP response element)-like sites at the distal end (CRE_osm). Deletion and point mutation of CRE_osm clearly indicated that this region imparted an important role in PGE₂-mediated transcription. Nuclear protein(s) from PGE₂-treated U937 cells, bound to this region, was identified as CRE-binding protein (CREB). CREB was phosphorylated on treatment and was found to be directly associated with CRE_osm The presence of cofactors p300 and CREB-binding protein in the complex was confirmed. A marked decrease in CREB phosphorylation, binding and transcriptional inhibition on treatment with PKA (protein kinase A) inhibitor, H89 (N-[2-[[3-(4-bromophenyl)-2-propenyl]amino]ethyl]-5-soquinolinesulfonamide), revealed the role of phosphorylated CREB in osm transcription. Additionally, other nuclear protein(s) were specifically associated with the proximal GC region (GC_osm) post PGE₂ treatment, later confirmed to be specificity protein 1 (Sp1). Interestingly, Sp1 bound to the proximal osm promoter was found to be associated with phospho-CREB-p300 complex bound to the distal osm promoter. Knockdown of Sp1 abrogated the expression and functionality of OSM. Thus, the present study conclusively proves that these transcription factors, bound at the distal and proximal promoter elements are found to associate with each other in a DNA-dependent manner and both are responsible for the PGE₂-mediated transcriptional up-regulation of Oncostatin-M.

The barrier hypothesis and Oncostatin M: Restoration of epithelial barrier function as a novel therapeutic strategy for the treatment of type 2 inflammatory disease

Mucosal epithelium maintains tissue homeostasis through many processes, including epithelial barrier function, which separates the environment from the tissue. The barrier hypothesis of type 2 inflammatory disease postulates that epithelial and epidermal barrier dysfunction, which cause inappropriate exposure to the environment, can result in allergic sensitization and development of type 2 inflammatory disease. The restoration of barrier dysfunction once it's lost, or the prevention of barrier dysfunction, have the potential to be exciting new therapeutic strategies for the treatment of type 2 inflammatory disease. Neutrophil-derived Oncostatin M has been shown to be a potent disrupter of epithelial barrier function through the induction of epithelial-mesenchymal transition (EMT). This review will discuss these events and outline several points along this axis at which therapeutic intervention could be beneficial for the treatment of type 2 inflammatory diseases.

A Poly(Lactic-co-Glycolic) Acid Nanovaccine Based on Chimeric Peptides from Different Leishmania infantum Proteins Induces Dendritic Cells Maturation and Promotes Peptide-Specific IFNγ-Producing CD8+ T Cells Essential for the Protection against Experimental Visceral Leishmaniasis

Visceral leishmaniasis, caused by Leishmania (L.) donovani and L. infantum protozoan parasites, can provoke overwhelming and protracted epidemics, with high case-fatality rates. An effective vaccine against the disease must rely on the generation of a strong and long-lasting T cell immunity, mediated by CD4⁺ T_H1 and CD8⁺ T cells. Multi-epitope peptide-based vaccine development is manifesting as the new era of vaccination strategies against Leishmania infection. In this study, we designed chimeric peptides containing HLA-restricted epitopes from three immunogenic L. infantum proteins (cysteine peptidase A, histone H1, and kinetoplastid membrane protein 11), in order to be encapsulated in poly(lactic-co-glycolic) acid nanoparticles with or without the adjuvant monophosphoryl lipid A (MPLA) or surface modification with an octapeptide targeting the tumor necrosis factor receptor II. We aimed to construct differentially functionalized peptide-based nanovaccine candidates and investigate their capacity to stimulate the immunomodulatory properties of dendritic cells (DCs), which are critical regulators of adaptive immunity generated upon vaccination. According to our results, DCs stimulation with the peptide-based nanovaccine candidates with MPLA incorporation or surface modification induced an enhanced maturation profile with prominent IL-12 production, promoting allogeneic T cell proliferation and intracellular production of IFNγ by CD4⁺ and CD8⁺ T cell subsets. In addition, DCs stimulated with the peptide-based nanovaccine candidate with MPLA incorporation exhibited a robust transcriptional activation, characterized by upregulated genes indicative of vaccine-driven DCs differentiation toward type 1 phenotype. Immunization of HLA A2.1 transgenic mice with this peptide-based nanovaccine candidate induced peptide-specific IFNγ-producing CD8⁺ T cells and conferred significant protection against L. infantum infection. Concluding, our findings supported that encapsulation of more than one chimeric multi-epitope peptides from different immunogenic L. infantum proteins in a proper biocompatible delivery system with the right adjuvant is considered as an improved promising approach for the development of a vaccine against VL.

Immunomodulatory properties of the IL-6 cytokine family in multiple sclerosis

Multiple sclerosis (MS) is a chronic disabling autoimmune disease of the central nervous system. The interleukin (IL)-6 cytokine family plays a crucial role in regulating the immune response in MS. All members of the IL-6 family share the common signal-transducing receptor protein, glycoprotein 130. Although the intracellular signaling of these cytokines seems to be largely overlapping, they have diverse and contrasting effects on the immune response. This review focuses on the effects of the family members IL-6, leukemia inhibitory factor, oncostatin M, and IL-11 on immune cell subsets and how these effects relate to the pathogenesis of MS. Finally, we propose possible avenues to modulate these family members for future MS therapy.

Genes specifically modulated in sensitized skins allow the detection of sensitizers in a reconstructed human skin model. Development of the SENS-IS assay

Analysis of genes modulated during the sensitization process either on mice (LLNA) or human (blisters) combined with data mining has allowed the definition of a comprehensive panel of sensitization biomarkers. This set of genes includes already identified markers such as the ARE family and others not yet associated with the sensitization process (the so-called SENS-IS gene subset). The expression of this set of genes has been measured on reconstituted human epidermis models (Episkin) exposed to various sensitizers and non-sensitizers. Fine analysis of their expression pattern indicates that it is the number of modulated genes rather than the intensity of up-regulation that correlates best with the sensitization potential of a chemical. Moreover, sensitizers that are weak inductors of ARE genes tend to be relevant modulators of the SENS-IS subset. By combining the expression data obtained with both gene subsets, it is now possible to identify a wide variety of sensitizers on a test system (in vitro reconstructed human epidermis) that is very similar to the in vivo situation and compatible with a large variety of test substance characteristics.

Characterization of the CD40L/Oncostatin M/Oncostatin M receptor axis as an antiviral and immunostimulatory system disrupted in chronic HCV infection

BACKGROUND & AIMS

Oncostatin M (OSM) is an inflammatory cytokine which interacts with a heterodimeric receptor formed by gp130 and either OSMRβ or LIFR. Here we have analysed OSM and its receptors in livers with chronic hepatitis C (CHC) and studied the factors that regulate this system.

METHODS

OSM, OSM receptors and OSM-target molecules were studied by immunohistochemistry and/or qPCR analysis in livers from CHC patients and controls. We determined the production of OSM by CD40L-stimulated antigen presenting cells (APC) and its biological effects on HuH7 cells containing HCV replicon (HuH7 Core-3').

RESULTS

OSM was upregulated in livers with CHC and its production was mapped to CD11c+ cells. OSM levels correlated directly with inflammatory activity and CD40L expression. In vitro studies showed that OSM is released by APC upon interaction with activated CD4+ T cells in a CD40L-dependent manner. Culture of HuH7 Core-3' cells with supernatant from CD40L-stimulated APC repressed HCV replication and induced IL-7 and IL-15Rα. These effects were dampened by antibodies blocking OSM or gp130 and by silencing OSMRβ. In CHC livers OSMRβ and LIFR were significantly downregulated and their values correlated with those of OSM-induced molecules. Experiments in HuH7 cells showed that impaired STAT3 signaling and exposure to TGFβ1, two findings in CHC, are factors involved in repressing OSMRβ and LIFR, respectively.

CONCLUSIONS

OSM is a cytokine possessing vigorous antiviral and immunostimulatory properties which is released by APC upon interaction with CD40L present on activated CD4+ T cells. In livers with CHC, OSM is overexpressed but its biological activity appears to be hampered because of downregulation of its receptor subunits.

Characterization of SLCO5A1/OATP5A1, a solute carrier transport protein with non-classical function

Organic anion transporting polypeptides (OATP/SLCO) have been identified to mediate the uptake of a broad range of mainly amphipathic molecules. Human OATP5A1 was found to be expressed in the epithelium of many cancerous and non-cancerous tissues throughout the body but protein characterization and functional analysis have not yet been performed. This study focused on the biochemical characterization of OATP5A1 using Xenopus laevis oocytes and Flp-In T-REx-HeLa cells providing evidence regarding a possible OATP5A1 function. SLCO5A1 is highly expressed in mature dendritic cells compared to immature dendritic cells (∼6.5-fold) and SLCO5A1 expression correlates with the differentiation status of primary blood cells. A core- and complex- N-glycosylated polypeptide monomer of ∼105 kDa and ∼130 kDa could be localized in intracellular membranes and on the plasma membrane, respectively. Inducible expression of SLCO5A1 in HeLa cells led to an inhibitory effect of ∼20% after 96 h on cell proliferation. Gene expression profiling with these cells identified immunologically relevant genes (e.g. CCL20) and genes implicated in developmental processes (e.g. TGM2). A single nucleotide polymorphism leading to the exchange of amino acid 33 (L→F) revealed no differences regarding protein expression and function. In conclusion, we provide evidence that OATP5A1 might be a non-classical OATP family member which is involved in biological processes that require the reorganization of the cell shape, such as differentiation and migration.

Pulmonary expression of oncostatin M (OSM) promotes inducible BALT formation independently of IL-6, despite a role for IL-6 in OSM-driven pulmonary inflammation

Inducible BALT (iBALT) is associated with immune responses to respiratory infections as well as with local pathology derived from chronic inflammatory lung diseases. In this study, we assessed the role of oncostatin M (OSM) in B cell activation and iBALT formation in mouse lungs. We found that C57BL/6 mice responded to an endotracheally administered adenovirus vector expressing mouse OSM, with marked iBALT formation, increased cytokine (IL-4, IL-5, IL-6, IL-10, TNF-α, and IL-12), and chemokine (CXCL13, CCL20, CCL21, eotaxin-2, KC, and MCP-1) production as well as inflammatory cell accumulation in the airways. B cells, T cells, and dendritic cells were also recruited to the lung, where many displayed an activated phenotype. Mice treated with control adenovirus vector (Addl70) were not affected. Interestingly, IL-6 was required for inflammatory responses in the airways and for the expression of most cytokines and chemokines. However, iBALT formation and lymphocyte recruitment to the lung tissue occurred independently of IL-6 and STAT6 as assessed in gene-deficient mice. Collectively, these results support the ability of OSM to induce B cell activation and iBALT formation independently of IL-6 and highlight a role for IL-6 downstream of OSM in the induction of pulmonary inflammation.

The Mycobacterium avium subsp. paratuberculosis fibronectin attachment protein, a toll-like receptor 4 agonist, enhances dendritic cell-based cancer vaccine potency

In this study, we showed the direct interaction between Mycobacterium avium subsp. paratuberculosis fibronectin attachment protein (FAP) and toll-like receptor4 (TLR4) via co-localization and binding by using confocal microscopy and co-immunoprecipitation assays. FAP triggered the expression of pro- and anti-inflammatory cytokines in a TLR4-dependent manner. In addition, FAP-induced cytokine expression in bone marrow-derived dendritic cells (BMDCs) was modulated in part by glycogen synthase kinase-3 (GSK-3). FAP-induced expression of CD80, CD86, major histocompatibility complex (MHC) class I, and MHC class II in TLR4^+/+ BMDCs was not observed in TLR4^-/- BMDCs. Furthermore, FAP induced DC-mediated CD8⁺ T cell proliferation and cytotoxic T lymphocyte (CTL) activity, and suppressed tumor growth with DC-based tumor vaccination in EG7 thymoma murine model. Taken together, these results indicate that the TLR4 agonist, FAP, a potential immunoadjuvant for DC-based cancer vaccination, improves the DC-based immune response via the TLR4 signaling pathway.

Functional properties of extracellular domains of transducer receptor gp130

Cytokine receptor molecules have been shown to have extracellular domains of complex structure and a multi-step activation system. Glycoprotein gp130 is a typical transducer of cytokine signal; it functions by forming multicomponent receptor complexes and transferring signals of tens of cytokines from the IL-6 family. Structural organization and basic functioning principles of gp130 are well known, as well as related signal pathways, which function during normal differentiation and are involved in pathogenesis of many tumors. The role of gp130 in IL-6-dependent tumors is best studied. In this review, based on extensive accumulated data, we examine the functional significance of certain parts of gp130 extracellular domains. Potentials of a recently developed method for estimation of receptor activation at the level of epitope structure are discussed.