Mechanism of interferon-gamma production by monocytes stimulated with myeloperoxidase and neutrophil extracellular traps

A retrospective analysis of the clinicopathological features and prognostic value of MAPK12 protein expression in diffuse large B-cell lymphoma

PURPOSE

Mitogen-activated protein kinase 12 (MAPK12), also known as p38γ, is a member of the p38 MAPK family and plays a crucial role in tumor occurrence and invasion. However, there is still uncertainty regarding MAPK12 involvement in diffuse large B-cell lymphoma (DLBCL).

METHODS

Our study investigated the expression of MAPK12 mRNA in various types of cancer using bioinformatic analysis. Furthermore, we performed immunohistochemistry (IHC) to detect the expression of MAPK12 in patients with DLBCL and compared clinical indicators and survival rates.

RESULTS

We found that the high expression rate of MAPK12 was 43.1% in DLBCL patients. Several clinical indicators, including IPI scores, Hans classifications, LDH levels, and Ki-67 expression were closely associated with MAPK12 expression. Survival analysis revealed that higher expression of MAPK12 was significantly correlated with shorter progression-free survival (PFS) and overall survival (OS) in DLBCL patients. In addition, both univariate and multivariate analyses revealed IPI score, MAPK12 expression, and rituximab use as the independent OS risk factors (P < 0.05). To explore the functional role of MAPK12 in DLBCL, weighted gene co-expression network analysis (WGCNA) and gene ontology (GO) were used to confirm the involvement of MAPK12 in the regulation of type II interferon production, positive regulation of lymphocyte proliferation, and other related biological processes.

CONCLUSION

DLBCL patients have poor prognoses when MAPK12 levels are high, which is expected to be a therapeutic target and prognostic factor.

Neutrophil extracellular traps in intracerebral hemorrhage: implications for pathogenesis and therapeutic targets

Intracerebral hemorrhage is a common neurological disease, and its pathological mechanism is complex. As the first recruited leukocyte subtype after intracerebral hemorrhage, neutrophils play an important role in tissue damage. In the past, it was considered that neutrophils performed their functions through phagocytosis, chemotaxis, and degranulation. In recent years, studies have found that neutrophils also have the function of secreting extracellular traps. Extracellular traps are fibrous structure composed of chromatin and granular proteins, which plays an important role in innate immunity. Studies have shown a large number of neutrophil extracellular traps in hematoma samples, plasma samples, and drainage samples after intracerebral hemorrhage. In this paper, we summarized the related mechanisms of neutrophil external traps and injury after intracerebral hemorrhage. Neutrophil extracellular traps are involved in the process of brain injury after intracerebral hemorrhage. The application of related inhibitors to inhibit the formation of neutrophil external traps or promote their dissolution can effectively alleviate the pathological damage caused by intracerebral hemorrhage.

P38 kinase in gastrointestinal cancers

Gastrointestinal cancers are a leading cause of cancer morbidity and mortality worldwide with 4.2 million new cases and 3.2 million deaths estimated in 2020. Despite the advances in primary and adjuvant therapies, patients still develop distant metastases and require novel therapies. Mitogen‑activated protein kinase (MAPK) cascades are crucial signaling pathways that regulate many cellular processes, including proliferation, differentiation, apoptosis, stress responses and cancer development. p38 Mitogen Activated Protein Kinases (p38 MAPKs) includes four isoforms: p38α (MAPK14), p38β (MAPK11), p38γ (MAPK12), and p38δ (MAPK13). p38 MAPK was first identified as a stress response protein kinase that phosphorylates different transcriptional factors. Dysregulation of p38 pathways, in particular p38γ, are associated with cancer development, metastasis, autophagy and tumor microenvironment. In this article, we provide an overview of p38 and p38γ with respect to gastrointestinal cancers. Furthermore, targeting p38γ is also discussed as a potential therapy for gastrointestinal cancers.

Phorbol-12-myristate-13-acetate is a potent enhancer of B cells with a granzyme B+ regulatory phenotype

Introduction

The infusion of ex-vivo-generated regulatory B cells may represent a promising novel therapeutic approach for a variety of autoimmune and hyperinflammatory conditions including graft-versus-host disease.

Methods

Previously, we developed a protocol for the generation of a novel population of regulatory B cells, which are characterized by secretion of enzymatically active granzyme B (GraB cells). This protocol uses recombinant interleukin 21 (IL-21) and goat-derived F(ab)'2 fragments against the human B cell receptor (anti-BCR). Generally, the use of xenogeneic material for the manufacturing of advanced therapy medicinal products should be avoided to prevent adverse immune reactions as well as potential transmission of so far unknown diseases.

Results

In the present work we demonstrated that phorbol-12-myristate-13-acetate (PMA/TPA), a phorbol ester with a particular analogy to the second messenger diacylglycerol (DAG), is a potent enhancer of IL-21-induced differentiation of pre-activated B cells into GraB cells. The percentage of GraB cells after stimulation of pre-activated B cells with IL-21 and PMA/TPA was not significantly lower compared to stimulation with IL-21 and anti-BCR.

Discussion

Given that PMA/TPA has already undergone encouraging clinical testing in patients with certain haematological diseases, our results suggest that PMA/TPA may be a safe and feasible alternative for ex-vivo manufacturing of GraB cells.

The Role of p38γ in Cancer: From review to outlook

p38γ is a member of the p38 Mitogen Activated Protein Kinases (p38 MAPKs). It contains four subtypes in mammalian cells encoded by different genes including p38α (MAPK14), p38β (MAPK11), p38γ (MAPK12), and p38δ (MAPK13). Recent studies revealed that p38γ may exhibit a crucial role in tumorigenesis and cancer aggressiveness. Despite the large number of published literatures, further researches are demanded to clarify its role in cancer development, the tissue-specific function and associated novel treatment strategies. In this article, we provide the latest view on the connection between p38γ and malignant tumors, highlighting the function of p38γ. The clinical value of p38γ is also discussed, helping the translation into the remarkable therapeutic strategy in tumor diseases.

Role of neutrophils in acute viral infection

Neutrophils play multiple roles in acute viral infections. They restrict viral replication and diffusion through phagocytosis, degranulation, respiratory burst, secretion of cytokines, and the release of neutrophil extracellular traps, as well as, activate the adaptive immune response. However, the overactivation of neutrophils may cause tissue damage and lead to poor outcomes. Additionally, some characteristics and functions of neutrophils, such as cell number, lifespan, and antiviral capability, can be influenced while eliminating viruses. This review provides a general description of the protective and pathological roles of neutrophils in acute viral infection.

Vertically transferred maternal immune cells promote neonatal immunity against early life infections

During mammalian pregnancy, immune cells are vertically transferred from mother to fetus. The functional role of these maternal microchimeric cells (MMc) in the offspring is mostly unknown. Here we show a mouse model in which MMc numbers are either normal or low, which enables functional assessment of MMc. We report a functional role of MMc in promoting fetal immune development. MMc induces preferential differentiation of hematopoietic stem cells in fetal bone marrow towards monocytes within the myeloid compartment. Neonatal mice with higher numbers of MMc and monocytes show enhanced resilience against cytomegalovirus infection. Similarly, higher numbers of MMc in human cord blood are linked to a lower number of respiratory infections during the first year of life. Our data highlight the importance of MMc in promoting fetal immune development, potentially averting the threats caused by early life exposure to pathogens.

Maternal immune cells seed into the foetus during mammalian pregnancy, yet the functional role of these cells is unclear. Here the authors show that maternal immune cells in foetal bone marrow stimulate immune development, subsequently reducing the risk or severity of infections in newborns.

Clinical findings of Talaromyces marneffei infection among patients with anti-interferon-γ immunodeficiency: a prospective cohort study

Background

Talaromyces marneffei (T. marneffei) infection has been associated with adult-onset immunodeficiency due to anti-IFN-γ autoantibodies. We aimed to investigate the clinical features of non-HIV-infected patients with T. marneffei infection in southern China.

Methods

Between January 2018 and September 2020, we enrolled patients with T. marneffei infection who were HIV-negative (group TM, n = 42), including anti-IFN-γ autoantibody-positive (group TMP, n = 22) and anti-IFN-γ autoantibody-negative (group TMN, n = 20) patients and healthy controls (group HC, n = 40). Anti-IFN-γ autoantibodies were detected by ELISA. Clinical characteristics and clinical laboratory parameters were recorded.

Results

Compared with anti-IFN-γ autoantibody-negative patients with T. marneffei infection, anti-IFN-γ autoantibody-positive patients did not have underlying respiratory disease; more frequently exhibited dissemination of systemic infections with severe pleural effusion; had higher WBC counts, C-reactive protein levels, erythrocyte sedimentation rates, and neutrophil and CD8⁺ T cell counts; had lower hemoglobin levels; and were more likely to have other intracellular pathogen infections. Most of these patients had poor outcomes despite standardized antimicrobial therapy.

Conclusion

T. marneffei-infected patients with higher anti-IFN-γ autoantibody titers have more severe disease and complex clinical conditions.

Flipside of the Coin: Iron Deficiency and Colorectal Cancer

Iron deficiency, with or without anemia, is the most frequent hematological manifestation in individuals with cancer, and is especially common in patients with colorectal cancer. Iron is a vital micronutrient that plays an essential role in many biological functions, in the context of which it has been found to be intimately linked to cancer biology. To date, however, whereas a large number of studies have comprehensively investigated and reviewed the effects of excess iron on cancer initiation and progression, potential interrelations of iron deficiency with cancer have been largely neglected and are not well-defined. Emerging evidence indicates that reduced iron intake and low systemic iron levels are associated with the pathogenesis of colorectal cancer, suggesting that optimal iron intake must be carefully balanced to avoid both iron deficiency and iron excess. Since iron is vital in the maintenance of immunological functions, insufficient iron availability may enhance oncogenicity by impairing immunosurveillance for neoplastic changes and potentially altering the tumor immune microenvironment. Data from clinical studies support these concepts, showing that iron deficiency is associated with inferior outcomes and reduced response to therapy in patients with colorectal cancer. Here, we elucidate cancer-related effects of iron deficiency, examine preclinical and clinical evidence of its role in tumorigenesis, cancer progression and treatment response. and highlight the importance of adequate iron supplementation to limit these outcomes.

Novel CD11b+Gr-1+Sca-1+ myeloid cells drive mortality in bacterial infection

Extreme pathophysiological stressors induce expansion of otherwise infrequent leukocyte populations. Here, we found a previously unidentified CD11b⁺Gr-1⁺ myeloid cell population that expresses stem cell antigen-1 (Sca-1) induced upon experimental infection with Staphylococcus aureus. Although CD11b⁺Gr-1⁺Sca-1⁺ cells have impaired migratory capacity and superoxide anion-producing activity, they secrete increased levels of several cytokines and chemokines compared to Sca-1^- counterparts. The generation of CD11b⁺Gr-1⁺Sca-1⁺ cells is dependent on IFN-γ in vivo, and in vitro stimulation of bone marrow cells or granulocyte-macrophage progenitors with IFN-γ generated CD11b⁺Gr-1⁺Sca-1⁺ cells. Depletion of CD11b⁺Gr-1⁺Sca-1⁺ cells by administrating anti-Sca-1 antibody strongly increased survival rates in an S. aureus infection model by reducing organ damage and inflammatory cytokines. However, adoptive transfer of CD11b⁺Gr-1⁺Sca-1⁺ cells decreased survival rates by worsening the pathogenesis of S. aureus infection. Together, we found a previously unidentified pathogenic CD11b⁺Gr-1⁺Sca-1⁺ population that plays an essential role in mortality during bacterial infection.

Genetic Variants in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: A Bayesian Approach and Systematic Review

A number of genome-wide association studies (GWASs) and meta-analyses of genetic variants have been performed in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. We reinterpreted previous studies using false-positive report probability (FPRP) and Bayesian false discovery probability (BFDP). This study searched publications in PubMed and Excerpta Medica Database (EMBASE) up to February 2018. Identification of noteworthy associations were analyzed using FPRP and BFDP, and data (i.e., odds ratio (OR), 95% confidence interval (CI), p-value) related to significant associations were separately extracted. Using filtered gene variants, gene ontology (GO) enrichment analysis and protein⁻protein interaction (PPI) networks were performed. Overall, 241 articles were identified, and 7 were selected for analysis. Single nucleotide polymorphisms (SNPs) discovered by GWASs were shown to be noteworthy, whereas only 27% of significant results from meta-analyses of observational studies were noteworthy. Eighty-five percent of SNPs with borderline p-values (5.0 × 10-8 < p < 0.05) in GWASs were found to be noteworthy. No overlapping SNPs were found between PR3-ANCA and MPO-ANCA vasculitis. GO analysis revealed immune-related GO terms, including "antigen processing and presentation of peptide or polysaccharide antigen via major histocompatibility complex (MHC) class II", "interferon-gamma-mediated (IFN-γ) signaling pathway". By using FPRP and BFDP, network analysis of noteworthy genetic variants discovered genetic risk factors associated with the IFN-γ pathway as novel mechanisms potentially implicated in the complex pathogenesis of ANCA-associated vasculitis.

Biological and Immunological Aspects of Iron Deficiency Anemia in Cancer Development: A Narrative Review

Iron Deficiency Anemia (IDA) is a universal health problem and a risk factor for the development of cancer. IDA changes the microenvironment of the human body by affecting both the biological and immunological systems. It increases DNA damage and genomic instability by different mechanisms. IDA is one of the leading causes of the imbalance between different antioxidant enzymes as well as enzymes involved in DNA damage and DNA repair systems of the body. It can affect the biogenesis/expression of microRNAs. IDA interrupts the oxidative phosphorylation energy metabolism and intestinal Cytochrome-P450 systems. It also disturbs multicellular signaling pathways involved in cell survival and helps in tumor angiogenesis. Moreover, IDA is also responsible for the functional deterioration of innate and adaptive immune systems that lead to immunological dysfunctions against invading pathogens. Genomic instability and immunological dysfunctions are the hallmarks of cancer development. In this review, we will review the evidence linking IDA to increased cancer risk.

Myeloperoxidase as an Active Disease Biomarker: Recent Biochemical and Pathological Perspectives

Myeloperoxidase (MPO) belongs to the family of heme-containing peroxidases, produced mostly from polymorphonuclear neutrophils. The active enzyme (150 kDa) is the product of the MPO gene located on long arm of chromosome 17. The primary gene product undergoes several modifications, such as the removal of introns and signal peptides, and leads to the formation of enzymatically inactive glycosylated apoproMPO which complexes with chaperons, producing inactive proMPO by the insertion of a heme moiety. The active enzyme is a homodimer of heavy and light chain protomers. This enzyme is released into the extracellular fluid after oxidative stress and different inflammatory responses. Myeloperoxidase is the only type of peroxidase that uses H₂O₂ to oxidize several halides and pseudohalides to form different hypohalous acids. So, the antibacterial activities of MPO involve the production of reactive oxygen and reactive nitrogen species. Controlled MPO release at the site of infection is of prime importance for its efficient activities. Any uncontrolled degranulation exaggerates the inflammation and can also lead to tissue damage even in absence of inflammation. Several types of tissue injuries and the pathogenesis of several other major chronic diseases such as rheumatoid arthritis, cardiovascular diseases, liver diseases, diabetes, and cancer have been reported to be linked with MPO-derived oxidants. Thus, the enhanced level of MPO activity is one of the best diagnostic tools of inflammatory and oxidative stress biomarkers among these commonly-occurring diseases.

Kaempferol and Chrysin Synergies to Improve Septic Mice Survival

Previously, we reported the role of synergy between two flavonoids—namely, chrysin and kaempferol—in inhibiting the secretion of a few major proinflammatory mediators such as tumor necrosis factor-alpha (TNF-α), prostaglandin E₂ (PGE₂), and nitric oxide (NO) from lipopolysaccharide (LPS)-induced RAW 264.7 cells. The present study aims to evaluate the effects of this combination on a murine model of polymicrobial sepsis induced by cecal ligation and puncture (CLP). Severe sepsis was induced in male ICR mice (n = 7) via the CLP procedure. The effects of chrysin and kaempferol combination treatment on septic mice were investigated using a 7-day survival study. The levels of key proinflammatory mediators and markers—such as aspartate aminotransferase (AST), TNF-α, and NO—in the sera samples of the septic mice were determined via ELISA and fluorescence determination at different time point intervals post-CLP challenge. Liver tissue samples from septic mice were harvested to measure myeloperoxidase (MPO) levels using a spectrophotometer. Moreover, intraperitoneal fluid (IPF) bacterial clearance and total leukocyte count were also assessed to detect any antibacterial effects exerted by chrysin and kaempferol, individually and in combination. Kaempferol treatment improved the survival rate of CLP-challenged mice by up to 16%. During this treatment, kaempferol expressed antibacterial, antiapoptotic and antioxidant activities through the attenuation of bacterial forming units, AST and NO levels, and increased polymorphonuclear leukocyte (PMN) count in the IPF. On the other hand, the chrysin treatment significantly reduced serum TNF-α levels. However, it failed to significantly improve the survival rate of the CLP-challenged mice. Subsequently, the kaempferol/chrysin combination treatment significantly improved the overall 7-day survival rate by 2-fold—up to 29%. Kaempferol and chrysin revealed some synergistic effects by acting individually upon multiple pathophysiological factors involved during sepsis. Although the kaempferol/chrysin combination did not exhibit significant antibacterial effects, it did exhibit anti-inflammatory and antioxidant activities, which translate to significant improvement in the survival rate of septic animals. These findings suggest the potential application of this combination treatment as a beneficial adjuvant supplement strategy in sepsis control.

Understanding the molecular mechanisms of NETs and their role in antiviral innate immunity

Polymorphonuclear neutrophils (PMNs) are the most abundant cells in the context of innate immunity; they are one of the first cells to arrive at the site of viral infection constituting the first line of defense in response to invading pathogens. Indeed, neutrophils are provided with several defense mechanisms including release of cytokines, cytotoxic granules and the last recently described neutrophil extracellular traps (NETs). The main components of NETs are DNA, granular antimicrobial peptides, and nuclear and cytoplasmic proteins, that together play an important role in the innate immune response. While NETs were first described as a mechanism against bacteria and fungi, recently, several studies are beginning to elucidate how NETs are involved in the host antiviral response and the prominent characteristics of this new mechanism are discussed in the present review.

Roles of myeloperoxidase and GAPDH in interferon-gamma production of GM-CSF-dependent macrophages

Interferon (IFN)-gamma is highly expressed in atherosclerotic lesions and may have an important role in atherogenesis. Myeloperoxidase (MPO), the most abundant protein in neutrophils, is a marker of plaque vulnerability and a possible bridge between inflammation and cardiovascular disease. Granulocyte-macrophage colony-stimulating factor (GM-CSF) has also been implicated in the pathogenesis of atherosclerosis. The present study investigated the role of neutrophil activation in atherosclerosis. Adherent macrophages were obtained from primary cultures of human mononuclear cells. Expression of IFN-gamma protein by GM-CSF-dependent-macrophages was investigated by enzyme-linked immunosorbent assay after stimulation with MPO. GM-CSF enhanced macrophage expression of the mannose receptor (CD206), which is involved in MPO uptake. MPO increased IFN-gamma production by GM-CSF-dependent macrophages in a concentration-dependent manner. Pretreatment of macrophages with small interfering RNA (siRNA) for CD206 or extracellular signal-regulated kinase (ERK)-2 attenuated IFN-gamma production, while siRNA for ERK-1 did not. GAPDH is known to bind to adenylate/uridylate (AU)-rich elements of RNA and may influence IFN-gamma protein expression by binding to the AU-rich element of IFN-gamma mRNA. Interestingly, pretreatment with siRNA for GAPDH significantly reduced IFN-gamma production by macrophages, while it did not affect TF protein expression. In conclusion, MPO upregulates IFN-gamma production by GM-CSF-dependent-macrophages via the CD206/ERK-2 signaling pathway, while silencing GAPDH reduces IFN-gamma production.