The increased marginal zone B cells attenuates early inflammatory responses during sepsis in Gpr174 deficient mice

GPR174 plays a crucial role in immune responses, but the role of GPR174 in the pathological progress of sepsis remains incompletely understood. In this study, we generated a sepsis model by cecal ligation and puncture (CLP) to investigate the role of GPR174 in regulating functions and underlying mechanism of marginal zone B (MZ B) cells in sepsis. We found that in Gpr174 deficient mice, the number of splenic MZ B cells was increased. Moreover, Gpr174^−/− MZ B cells exhibited an enhanced response to LPS stimulation in vitro. By using the CLP-induced sepsis model, we demonstrated that the increased MZ B cells attenuated early inflammatory responses during sepsis. RNA sequencing results revealed that the expression of c-fos in splenic B lymphocytes was upregulated in Gpr174 deficient mice. However, the protective role of increased MZ B cells in Gpr174 deficient mice was weakened by a c-fos-specific inhibitor. Collectively, these findings suggested that GPR174 plays an immunomodulatory role in early immune responses during sepsis through the regulation of MZ B cells.     

The epigenetic face of lupus: Focus on antigen-presenting cells

In recent years, epigenetic mechanisms became widely known due to their ability to regulate and maintain physiological processes such as cell growth, development, differentiation and genomic stability. When dysregulated, epigenetic mechanisms, may introduce gene expression changes and disturbance in immune homeostasis leading to autoimmune diseases. Systemic lupus erythematosus (SLE), the most extensively studied autoimmune disorder, has already been correlated with epigenetic modifications, especially in T cells. Since these cell rely on antigen presentation, it may be assumed that erroneous activity of antigen-presenting cells (APCs), culminates in T cell abnormalities. In this review we summarize and discuss the epigenetic modifications in SLE affected APCs, with the focus on dendritic cells (DCs), B cells and monocytes. Unravelling this aspect of SLE pathogenesis, might result in identification of new disease biomarkers and putative therapeutic approaches.     

Recent insights of the role and signalling pathways of interleukin-34 in liver diseases

Liver disease is a global health problem and is a primary cause of mortality and morbidity worldwide. Specifically, it accounts for approximately two million deaths per year worldwide. The common causes of mortality are the complications of liver cirrhosis, viral hepatitis and hepatocellular carcinoma (HCC). The mechanism of immune response and infiltration of cellular immunity is essential for promoting hepatic inflammatory, especially when the liver is abundant with lymphocytes and phagocytic cells. The injured and immunity cells secret different types of interleukins (cytokines), which can directly or indirectly amplify or inhibit liver inflammation. Many types of cells can produce interleukin-34 (IL-34) that induces the release of multiple inflammatory factors in patients via interaction with various cytokines. This phenomenon leads to the enlargement of the inflammatory response to liver diseases and induces liver fibrosis. This review highlights the proposed roles of IL-34 in liver diseases and discusses the recent findings of IL-34 that support its emerging role in HCC. Specifically, the facilitating effects of these new insights on the rational development of IL-34 for targeted therapies in the future are explored.     

Radiation of the urinary bladder attenuates the development of lipopolysaccharide-induced cystitis

In the present study we assessed how ionizing radiation affects TLR4-stimulated immune activation in lipopolysaccharide (LPS)-induced cystitis. LPS or saline was administered intravesically to female rats followed by urinary bladder irradiation (20 Gy) 24 h later or sham treatment. Presence in the urinary bladder of inflammatory cells (mast cells, CD3+, ionized calcium-binding adapter molecule 1 (Iba-1)+, CD68+, CD40+, CD80+, CD11c + and CD206 + cells) and expression of oxidative stress (8-OHdG), hypoxia (HIF1α) and anti-oxidative responses (NRF2, HO-1, SOD1, SOD2, catalase) were assessed 14 days later with western blot, qPCR and/or immunohistochemistry. LPS stimulation resulted in a decrease of Iba-1 + cells in the urothelium, an increase in mast cells in the submucosa and a decrease in the bladder protein expression of HO-1, while no changes in the bladder expression of 8-OHdG, NRF2, SOD1, SOD2, catalase and HIF1α were observed. Bladder irradiation inhibited the LPS-driven increase in mast cells and the decrease in Iba1 + cells. Combining LPS and radiation increased the expression of 8-OHdG and number of CD3-positive cells in the urothelium and led to a decrease in NRF2α gene expression in the urinary bladder. In conclusion, irradiation may attenuate LPS-induced immune responses in the urinary bladder but potentiates LPS-induced oxidative stress, which as a consequence may have an impact on the urinary bladder immune sensing of pathogens and danger signals.     

Pharmacological approaches to mitigate neuroinflammation in Alzheimer’s disease

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases characterized by the formation of extracellular amyloid beta (Aβ) plaques and intracellular neurofibrillary tangles (NFTs). Growing evidence suggested that there is an association between neuronal dysfunction and neuroinflammation (NI) in AD, coordinated by the chronic activation of astrocytes and microglial cells along with the subsequent excessive generation of the proinflammatory molecule. Therefore, a better understanding of the relationship between the nervous and immune systems is important in order to delay or avert the neurodegenerative events of AD. The inflammatory/immune pathways and the mechanisms to control these pathways may provide a novel arena to develop new drugs in order to target NI in AD. In this review, we represent the influence of cellular mediators which are involved in the NI process, with regards to the progression of AD. We also discuss the processes and the current status of multiple anti-inflammatory agents which are used in AD and have gone through or going through clinical trials. Moreover, new prospects for targeting NI in the development of AD drugs have also been highlighted.     

Alterations in peripheral blood B cells in systemic lupus erythematosus patients with renal insufficiency

ObjectiveSystemic lupus erythematosus (SLE) is one of the autoimmune diseases, believed to be closely related to hyperactivity of B cells, overproduction of autoantibodies and immune complex formation and deposition in affected tissue. The autoreactive inflammation leads to multiorgan damage with kidney dysfunction in the forefront. Studies on lupus nephritis (LN), affecting the majority of SLE patients, are mainly focused on cells causing local inflammation. The aim of our work was to detect alterations in more accessible peripheral blood B cells in the course of SLE focusing on the influence of renal insufficiency (RI) on those parameters.MethodsWe performed a comprehensive flow cytometry analysis of B cell subpopulations, analyzed gene expression patterns with qPCR, and examined serum cytokine levels with multiplex cytokine/chemokine assay.ResultsWe discovered distribution of specific B cell subsets, especially CD38⁺ cells, plasmablasts, associated with the presence and severity of the disease. Changes in expression of MBD2, DNMT1 and APRIL genes were not only associated with activity of SLE but also were significantly changed in patients with RI.ConclusionsAll these results shed new light on the role of circulating B cells, their subpopulations, function, and activity in the SLE with kidney manifestation.     

Current approaches used in treating COVID-19 from a molecular mechanisms and immune response perspective

Coronavirus disease 2019 (COVID-19), which is caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was declared by the World Health Organization (WHO) as a global pandemic on March 11, 2020. SARS-CoV-2 targets the respiratory system, resulting in symptoms such as fever, headache, dry cough, dyspnea, and dizziness. These symptoms vary from person to person, ranging from mild to hypoxia with acute respiratory distress syndrome (ARDS) and sometimes death. Although not confirmed, phylogenetic analysis suggests that SARS-CoV-2 may have originated from bats; the intermediary facilitating its transfer from bats to humans is unknown. Owing to the rapid spread of infection and high number of deaths caused by SARS-CoV-2, most countries have enacted strict curfews and the practice of social distancing while awaiting the availability of effective U.S. Food and Drug Administration (FDA)-approved medications and/or vaccines. This review offers an overview of the various types of coronaviruses (CoVs), their targeted hosts and cellular receptors, a timeline of their emergence, and the roles of key elements of the immune system in fighting pathogen attacks, while focusing on SARS-CoV-2 and its genomic structure and pathogenesis. Furthermore, we review drugs targeting COVID-19 that are under investigation and in clinical trials, in addition to progress using mesenchymal stem cells to treat COVID-19. We conclude by reviewing the latest updates on COVID-19 vaccine development. Understanding the molecular mechanisms of how SARS-CoV-2 interacts with host cells and stimulates the immune response is extremely important, especially as scientists look for new strategies to guide their development of specific COVID-19 therapies and vaccines.     

The role of nuclear factors as “Find-Me”/alarmin signals and immunostimulation in defective efferocytosis and related disorders

Efferocytosis as an apoptotic cell (AC) clearance mechanism facilitates the removal of dangerous and damaged cells, an important process in regulating normal homeostasis. Failure to correctly execute apoptosis and efferocytosis is associated with atherosclerosis, as well as chronic inflammatory and autoimmune disorders such as systemic lupus erythematosus (SLE). Effective and timely efferocytosis involves various molecules that act as “Find-Me” signals or as alarmins to quickly allow identification by phagocytic cells. In recent years, most of these molecules have been investigated, but less attention has been paid to the nuclear molecules associated with efferocytosis of ACs and necrotic cells (NCs). These molecules have several functions including acting as alarmin signals for faster recognition of ACs, facilitating the cleanup of ACs and for maintaining self-tolerance. The same group of molecules is also implicated in several inflammatory and autoimmune diseases. Previous studies have shown that these molecules also serve as targets for pharmacological agents such as necrostatins, recombinant Fcnb, anti-histone, neutralizing antibodies, calbiochem, aminophylline, activated protein C, CD24IgG recombinant fission protein, and recombinant thrombomodulin. Thus, greater understanding of these molecules/pathways will enable developments in the treatment and/or prevention of various disorders, especially autoimmune diseases. Here, we review current knowledge about the mechanisms by which nucleic acids, histones, nucleosomes and monosodium urate microcrystals (MSU) can act as alarmins/“Find-Me” signals, how they might be stimulated in defective efferocytosis and their function and importance as biomarkers for prognosis and treatment of atherosclerosis, inflammatory disorders and autoimmune diseases.     

Hydroxychloroquine is a novel therapeutic approach for rosacea

Rosacea is a chronic inflammatory disease in face. Hydroxychloroquine (HCQ), an anti-malaria drug, was reported to have anti-inflammation activities. However, the role of HCQ on rosacea remains unclear. In this study, we revealed the potential molecular mechanism by which HCQ improved rosacea in rosacea-like mice and mast cells (MCs). Moreover, the effects of HCQ treatment for rosacea patients were investigated. In this study, we found HCQ ameliorated the rosacea-like phenotype and MCs infiltration. The elevated pro-inflammatory factors and mast cell protease were significantly inhibited by HCQ treatment in rosacea-like mice. In vitro, HCQ suppresses LL37-induced MCs activation in vitro, including the release of inflammatory factors, chemotaxis, degranulation and calcium influx. Moreover, HCQ attenuated LL37-mediated MCs activation partly via inhibiting KCa3.1-mediated calcium signaling. Thus, these evidences suggest HCQ ameliorated rosacea-like dermatitis may be by regulating immune response of MCs. Finally, the 8-week HCQ treatment exerted satisfactory therapeutic effects on erythema and inflammatory lesions of rosacea patients, indicating that it is a promising drug for rosacea in clinical treatment.     

LncRNA AK085865 depletion ameliorates asthmatic airway inflammation by modulating macrophage polarization

Accumulating evidence indicates that regulators of macrophages polarization may play a key role in the development of allergic asthma (AA). However, the exact role of long non-coding RNAs (lncRNAs) in regulating in macrophages polarization in the pathogenesis of dermatophagoides farinae protein 1(Der f1)-induced AA is not fully understood. The purpose of this study was to determine the function of lncRNA AK085865 in regulating macrophages in AA. Here we report that lncRNA AK085865 served as a critical regulator of macrophages polarization and reduced the pathological progress of asthmatic airway inflammation. In response to the challenge of Der f1, AK085865^−/− mice displayed attenuated allergic airway inflammation, including decreased eosinophil in BALF and reduced production of IgE, which were associated with decreased mucous glands and goblet cell hyperplasia. In addition, Der f1-treated AK085865^−/− mice show fewer M2 macrophages when compared with WT asthmatic mice. After adopting bone marrow-derived macrophages (BMDM, M0) from WT mice, Der f1-treated AK085865^−/− mice also revealed a light inflammatory reactions. We further observed that the percentage of type II innate immune lymphoid cells (ILC2s) decreased in AK085865^−/− asthmatic mice. Moreover, M2 macrophages helped promote the differentiation of ILC2s, probably through the exosomal pathway secreted by M2 macrophages. Taken together, these findings reveal that AK085865 depletion can ameliorate asthmatic airway inflammation by modulating macrophage polarization and M2 macrophages can promote the differentiation of innate lymphoid cells progenitor (ILCP) into ILC2s.     

Alternative splicing implicated in immunity and prognosis of colon adenocarcinoma

Dysregulation of immune system is the hallmark of colon adenocarcinoma (COAD) patients. Aberrant alternative splicing (AS) is closely related to progression and immunotherapy of COAD. However, the intrinsic correlation of immune system with AS have not been elucidated. Here we identified 640 AS events related to immunescore by multi-omics data analysis. 7 key AS events were screened out and used to develop a riskscore model, the area under the ROC curve of riskscore model predicting 3-, 5-year survival probability was 0.750, 0.768. Also, the riskscore based on 7 key AS events is an independent prognostic factor. The AUC of the nomogram composed of riskscore and TMN grade reached to 0.872(3-year) and 0.841(5-year). Moreover, 11 AS events were identified to be associated with the infiltration of 8 types of immune cells. Interestingly, M1 macrophages and memory B cells had a higher infiltration in high-riskscore patients, and higher infiltration of M1 macrophages and memory B cells were significantly associated with worse prognosis. In conclusion, AS are closely related to immunescore, immunity stage and infiltrating immune cells. The riskscore is an effective diagnostic and prognostic indicator better than TMN grade, and AS events related to the immune system may be potential therapeutic targets for COAD.     

Lymphocyte expression of EZH2 is associated with mortality and secondary infectious complications in sepsis

Recent studies have shown that epigenetic factors may affect immune responses. We previously reported that histone methyltransferase enhancer of zeste homolog 2 (EZH2) was involved in the innate inflammatory responses both in animal model of sepsis and in septic patients. In this study, we prospectively evaluated EZH2 expression kinetics in peripheral CD4+ and CD8+ T cells and HLA-DR expression in CD14+ cells from 48 patients with sepsis and 48 healthy controls. Results showed higher level of EZH2 in CD4+ T cells and CD8+ T cells in sepsis patients than in controls. Meanwhile, EZH2 expression was correlated with CD27 status on T cells. Mean fluorescence intensity (MFI) of EZH2 in CD8+ T cells on day 1 independently predicted death in septic patients. Also, the combination of CD8+ T cell EZH2 expression with APACHEII and SOFA score could enhance the prognostic predictive ability. Moreover, multivariate logistic regression analysis showed that increased expression (proportion and MFI) of EZH2 in CD4+ and CD8+ lymphocytes on day 3 were independently associated with nosocomial infection in septic patients. Additionally, spearman correlation analysis indicated that the levels of EZH2 in CD4+ T cells and CD8+ T cells correlated to CD14+ cells-expressing HLA-DR in patients with sepsis at each time point. Overall, these findings suggest that EZH2 in CD4+ T cells or/and CD8+ T cells may be a novel biomarker for predicting adverse outcomes (mortality and secondary infectious complications) in patients with sepsis.     

Roles of TGF-β signaling pathway in tumor microenvirionment and cancer therapy

Transforming growth factor β (TGF- β) signaling pathway has pleiotropic effects on cell proliferation, differentiation, adhesion, senescence, and apoptosis. TGF-β can be widely produced by various immune or non-immune cells and regulate cell behaviors through autocrine and paracrine. It plays essential roles in biological processes including embryological development, immune response, and tumor progression. Few cell signalings can contribute to so many pleiotropic functions as the TGF- β signaling pathway in mammals. The significant function of TGF-β signaling in tumor progression and evasion leading it to draw great attention in scientific and clinical research. Understanding the mechanism of TGF- β signaling provides us with chances to potentiate the effectiveness and selectivity of this therapeutic method. Herein, we review the molecular and cellular mechanisms of TGF-β signaling in carcinomas and tumor microenvironment. Then, we enumerate main achievements of TGF-β blockades used or being evaluated in cancer therapy, providing us opportunities to improve therapeutical approaches in the tumor which thrive in a TGF-β-rich environment.     

Breast cancer cells promote CD169+ macrophage-associated immunosuppression through JAK2-mediated PD-L1 upregulation on macrophages

Macrophages are recognized as one of the major cell types in tumor microenvironment, and macrophage infiltration has been predominantly associated with poor prognosis among patients with breast cancer. Using the murine models of triple-negative breast cancer in CD169-DTR mice, we found that CD169⁺ macrophages support tumor growth and metastasis. CD169⁺ macrophage depletion resulted in increased accumulation of CD8⁺ T cells within tumor, and produced significant expansion of CD8⁺ T cells in circulation and spleen. In addition, we observed that CD169⁺ macrophage depletion alleviated tumor-induced splenomegaly in mice, but had no improvement in bone loss and repression of bone marrow erythropoiesis in tumor-bearing mice. Cancer cells and tumor associated macrophages exploit the upregulation of the immunosuppressive protein PD-L1 to subvert T cell-mediated immune surveillance. Within the tumor microenvironment, our understanding of the regulation of PD-L1 protein expression is limited. We showed that there was a 5-fold higher relative expression of PD-L1 on macrophages as compared with 4T1 tumor cells; coculture of macrophages with 4T1 cells augmented PD-L1 levels on macrophages, but did not upregulate the expression of PD-L1 on 4T1 cells. JAK2/STAT3 signaling pathway was activated in macrophages after coculture, and we further identified the JAK2 as a critical regulator of PD-L1 expression in macrophages during coculture with 4T1 cells. Collectively, our data reveal that breast cancer cells and CD169⁺ macrophages exhibit bidirectional interactions that play a critical role in tumor progression, and inhibition of JAK2 signaling pathway in CD169⁺ macrophages may be potential strategy to block tumor microenvironment-derived immune escape.     

Isolation and purification of immune cells from the liver

Isolating and purifying liver immune cells are crucial for observing the changes in intrahepatic immune responses during the development of liver diseases and exploring the potential immunological mechanisms. Therefore, the aim of this study was to provide an optimal protocol for isolating immune cells with a high yield and less damage. We compared mechanical dissection and collagenase digestion, and the results were represented by the proportion of lymphocytes, Kupffer cells and neutrophils. The apoptosis rates of liver immune cells resulted by different isolation protocols were compared by Annexin V-staining using flow cytometric analysis. Our data indicated that the enzymatic digestion in vitro was more efficient than the mechanical dissection in vitro with a suitable collagenase IV concentration of 0.01%, and the purification of liver immune cells by a one-step density gradient centrifugation in 33% Percoll had the definite advantage of a higher proportion of the target cells. We also provided evidence that enzymatic digestion in vitro method was superior to collagenase digestion in situ for liver T lymphocytes, NK cells and NKT cells isolation and purification. This protocol was also validated in human liver samples. In conclusion, we developed an optimal protocol for isolating and purifying immune cells from mouse and human liver samples in vitro by 0.01% collagenase IV and 33% Percoll density gradient centrifugation with the advantages of higher cell yields and viability. This method provides a basis for further studying liver immune cells and liver immunity with a wide range of applications.     

A guide to oral vaccination: Highlighting electrospraying as a promising manufacturing technique toward a successful oral vaccine development

Most vaccines approved by regulatory bodies are administered via intramuscular or subcutaneous injections and have shortcomings, such as the risk of needle-associated blood infections, pain and swelling at the injection site. Orally administered vaccines are of interest, as they elicit both systemic and mucosal immunities, in which mucosal immunity would neutralize the mucosa invading pathogen before the onset of an infection. Hence, oral vaccination can eliminate the injection associated adverse effects and enhance the person's compliance. Conventional approaches to manufacturing oral vaccines, such as coacervation, spray drying, and membrane emulsification, tend to alter the structural proteins in vaccines that result from high temperature, organic and toxic solvents during production. Electrohydrodynamic processes, specifically electrospraying, could solve these challenges, as it also modulates antigen release and has a high loading efficiency. This review will highlight the mucosal immunity and biological basis of the gastrointestinal immune system, different oral vaccine delivery approaches, and the application of electrospraying in vaccines development.