Induced IL-6 Production Research Articles

CCN1 Promotes Inflammation by Inducing IL-6 Production via α6β1/PI3K/Akt/NF-κB Pathway in Autoimmune Hepatitis.

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease with unknown etiology. CCN1, an extracellular matrix-associated protein, is associated with carcinoma, inflammation, liver fibrosis, and even autoimmune diseases. However, the role that CCN1 plays in AIH has remained undetermined. In this study, expression of CCN1 in liver was detected by real-time PCR, western blot and immunohistochemistry (IHC). CCN1 level in serum was detected by ELISA. Diagnostic value of CCN1 was determined by receiver operating characteristic (ROC) curve analysis. CCN1 conditional knockout (CCN1 fl/fl Cre+) mice were generated by mating CCN1 fl/fl C57BL/6J and CAG-Cre-ERT C57BL/6J mice. Autoimmune hepatitis mice model was induced by concanavalin A (ConA). IKKα/β, IκBα, NF-κB p65 and Akt phosphorylation were determined by western blot. NF-κB p65 nuclear translocation was examined by immunofluorescence. Here, we found that CCN1 was over-expressed in hepatocytes of AIH patients. CCN1 level also increased in serum of AIH patients compared to healthy controls (HC). ROC curve analysis results showed that serum CCN1 was able to distinguish AIH patients from HD. In ConA induced hepatitis mice model, CCN1 conditional knockout (CCN1 fl/fl Cre+) attenuated inflammation by reducing ALT/AST level and IL-6 expression. In vitro, CCN1 treatment dramatically induced IL-6 production in LO2 cells. Moreover, the production of IL-6 was attenuated by CCN1 knockdown. Furthermore, we showed that CCN1 could activate IL-6 production via the PI3K/Akt/NF-κB signaling pathway by binding to α6β1 receptor. In summary, our results reveal a novel role of CCN1 in promoting inflammation by upregulation of IL-6 production in AIH. Our study also suggests that targeting of CCN1 may represent a novel strategy in AIH treatment.

TLT-1 Promotes Platelet-Monocyte Aggregate Formation to Induce IL-10-Producing B Cells in Tuberculosis.

The immunoregulation of platelets and platelet-monocyte aggregates (PMAs) is increasingly recognized, but it roles in tuberculosis (TB) remain to be elucidated. In this study, we found that CD14+CD41+ PMAs were increased in peripheral blood of patients with active TB. CD14+CD41+ PMAs highly expressed triggering receptors expressed on myeloid cells (TREMs)-like transcript-1 (TLT-1), P-selectin (CD62P), and CD40L. Our in vitro study found that platelets from patients with active TB aggregate with monocytes to induce IL-1β and IL-6 production by monocytes. Importantly, we identified that TLT-1 was required for formation of PMAs. The potential TLT-1 ligand was expressed and increased on CD14+ monocytes of patients with TB determined by using TLT-1 fusion protein (TLT-1 Fc). Blocking of ligand-TLT-1 interaction with TLT-1 Fc reduced PMA formation and IL-1β and IL-6 production by monocytes. Further results demonstrated that PMAs induced IL-10 production by B cells (B10) dependent on IL-1β, IL-6, and CD40L signals in a coculture system. Moreover, TLT-1 Fc treatment suppressed B10 polarization via blocking PMA formation. Taking all of these data together, we elucidated that TLT-1 promoted PMA-mediated B10 polarization through enhancing IL-1β, IL-6, and CD40L origin from PMAs, which may provide potential targeting strategies for TB disease treatment.

Soluble C-Type Lectin-Receptor Ligands Stimulate ROS Production in Dendritic Cells and Potentiate Killing of MRSA as Well as the MRSA Induced IL-12 Production.

Methicillin resistant Staphylococcus aureus (MRSA) has developed resistance to most β-lactam antibiotics leaving few treatment options against infections with MRSA. Through mannose receptors, mannan potentiates IL-12 production induced by Gram-positive bacteria, a cytokine crucial in the clearance of S. aureus infection. We investigated the IL-12 potentiating effect of mannan pre-treatment of bone marrow-derived dendritic cells prior to stimulation with clinical MRSA strains. Mannan almost doubled IL-12 as well as IFN-β production in response to USA300, also when USA300 was treated with the β-lactam cefoxitin. The MRSA-induced IL-12 production was dependent on bacterial uptake and reactive oxygen species (ROS). Mannan alone induced ROS production, and in combination with USA300, the ROS produced corresponded to the sum induced by mannan and USA300. Addition of a monoclonal antibody against the mannose receptor likewise enhanced USA300-induced IL-12 and induced ROS production. Mannan addition further increased the endocytosis as well as the rate of endosomal killing of bacteria. Pre-treatment with soluble β-glucans also induced ROS and potentiated the USA300-induced IL-12 indicating that other C-type receptors may play a similar role. In the presence of the pro-inflammatory mediators, GM-CSF or IFN-γ, the mannan-enhanced IL-12 production increased further. The USA300-induced and the mannan-facilitated enhanced IFN-β and IL-12 showed same dependency on MAPK c-Jun N-terminal kinase signaling, suggesting that mannan enhances the signals already induced by the bacteria, rather than changing them. We suggest that the C-type lectin-induced ROS production is a key factor in the IFN-β and IL-12 potentiation.

Inflammasome NLRP3 activation induced by Convulxin, a C-type lectin-like isolated from Crotalus durissus terrificus snake venom

Convulxin (CVX), a C-type lectin-like protein isolated from the venom of the snake species, Crotalus durissus terrificus, stimulates platelet aggregation by acting as a collagen receptor agonist for glycoprotein VI found in the platelets. The effect of CVX on platelets has been studied, but its effect on human peripheral blood mononuclear cells (PBMCs) remains unclear. Given the significance of PBMCs in inflammation, this study explored the effect of CVX on PBMCs, specifically regarding NLRP3 inflammasome activation by assessing cell viability, ability to induce cell proliferation, reactive oxygen species (ROS) and nitric oxide production, interleukin (IL)-2 and IL-10 secretion, NLRP3 complex activation, and the role of C-type lectin-like receptors (CTLRs) in these. CVX was not toxic to PBMCs at the investigated concentrations and did not increase PBMC growth or IL-2 release; however, CVX induced IL-10 release and ROS generation via monocyte activation. It also activated the NLRP3 complex, resulting in IL-1β induction. Furthermore, the interaction between CVX and Dectin-2, a CTLR, induced IL-10 production. CVX interaction with CTLR has been demonstrated by laminarin therapy. Because of the involvement of residues near the Dectin-2 carbohydrate-recognition site, the generation of ROS resulted in inflammasome activation and IL-1β secretion. Overall, this work helps elucidate the function of CVX in immune system cells.

Glutamate in the medium of Lactiplantibacillus plantarum FL-664 affects the production of IL-12(p40) on murine spleen cells.

Lactic acid bacteria (LAB) have been attracting attention for their effects on innate immunity, and therefore, it is required to develop an efficient culturing method while maintaining their functionality. In this study, first, we compared the growth and functionality of LAB cultured on food grade (FG) medium with those on standard LAB medium and found that LAB cultured in the FG medium were smaller in cell size with high yield and had a higher ability to induce IL-12(p40) production by murine spleen cells in vitro. Moreover, the higher the glutamate concentration in the medium, the smaller the cell size, and the higher the yield and the higher the ability to induce IL-12 production. Addition of glutamate to the culture medium changes the size of LAB and affects their ability to induce IL-12(p40) production. In conclusion, regulating the concentration of glutamate would be important in the efficient culturing of functional LAB.

In-vitro and in-vivo anti-allergic effects of magnolol on allergic rhinitis via inhibition of ORAI1 and ANO1 channels

Ethnopharmacological relevanceFlos Magnoliae (the dried flower buds of Magnolia biondii Pamp, FM) is a known herbal traditional medicine used for the symptomatic relief of nasal congestion and rhinorrhea caused by rhinitis and sinusitis. Magnolol, a neolignan from the magnolia family, is a secondary metabolite known to have anti-allergic and anti-inflammatory effects. However, the underlying mechanisms and therapeutic effect of magnolol in the treatment of allergic rhinitis (AR) remain elusive. Aims of the studyAnoctamin 1 (ANO1), a calcium-activated anion channel, mediates mucus and electrolyte secretion in nasal airway epithelial cells, whereas calcium release-activated calcium channel protein 1 (ORAI1) participates in the activation of T-lymphocytes and mast cells. The aim of our study is to understand the mechanisms of action of magnolol against AR, i.e., whether it acts through the modulation of ANO1 and ORAI1 channels that are expressed in nasal epithelial cells and T-lymphocytes, respectively. Materials and methodsWhole-cell patch clamp was used to record the activity of ORAI1 and ANO1 ion channels in ORAI1 or ANO1 overexpressed HEK293T cells, while the Ussing chamber apparatus was used to measure electrolyte transport via the epithelium, in Calu-3 cells cultured in an air-liquid interface. Additionally, calcium imaging of Jurkat T-lymphocytes was used to assess changes in the intracellular calcium concentration. Magnolol toxicity was assessed using the CCK-8 assay, and its effect on T-lymphocyte proliferation was measured by labeling human primary T-lymphocytes with carboxyfluorescein succinimidyl ester. Finally, OVA-induced Balb/c mice were employed to evaluate the effect of magnolol on nasal symptoms, as well as cytokine and eosinophil infiltration in AR. ResultsMagnolol inhibits ORAI1 and ANO1 channels in a concentration-dependent manner. Magnolol (30 μM) inhibits anti-CD3 induced cellular proliferation and production of IL-2 via ORAI1 channels in T-lymphocytes. Further, ATP-induced electrolyte transport mediated by ANO1 channels is significantly inhibited by magnolol in IL-4 sensitized Calu-3 cells. Notably, 300 μM magnolol significantly attenuates cytokine and eosinophil infiltration, thus alleviating AR symptoms in mice OVA-induced AR. ConclusionMagnolol may be a promising therapeutic agent for the treatment and prevention of AR.

Coagulation factor-XII induces interleukin-6 by primary lung fibroblasts: a role in idiopathic pulmonary fibrosis?

The mechanisms driving idiopathic pulmonary fibrosis (IPF) remain undefined, however it is postulated that coagulation imbalances may play a role. The impact of blood-derived clotting factors, including factor XII (FXII) has not been investigated in the context of IPF. Plasma levels of FXII were measured by ELISA in patients with IPF and in age-matched healthy donors. Expression of FXII in human lung tissue was quantified using multiplex immunohistochemistry and Western blotting. Mechanistic investigation of FXII activity was assessed in vitro on primary lung fibroblasts using qPCR and specific receptor/FXII inhibition. The functional outcome of FXII on fibroblast migration was examined by high-content image analysis. Compared with 35 healthy donors, plasma levels of FXII were not higher in patients with IPF (n = 27, P > 0.05). Tissue FXII was elevated in IPF (n = 11) and increased numbers of FXII+ cells were found in IPF (n = 8) lung tissue compared with nondiseased controls (n = 6, P < 0.0001). Activated FXII induced IL6 mRNA and IL-6 protein in fibroblasts that was blocked by anti-FXII antibody, CSL312. FXII induced IL-6 production via PAR-1 and NF-κB. FXII induced migration of fibroblasts in a concentration-dependent manner. FXII is normally confined to the circulation but it leaks from damaged vessels into the lung interstitium in IPF where it 1) induces IL-6 production and 2) enhances migration of resident fibroblasts, critical events that drive chronic inflammation and therefore, contribute to fibrotic disease progression. Targeting FXII-induced fibroblastic processes in IPF may ameliorate pulmonary fibrosis.

The effect of carvacrol on respiratory syncytial virus infection in mice model: caution in the use of herbal medicines

Background and Objectives:Respiratory syncytial virus (RSV) is one of the most common viruses associated with acute lower respiratory tract infections in infants, young children, and the elderly. Due to a lack of effective anti-viral drugs or vaccines, using an immunomodulatory strategy is probably the best option to decrease the burden of RSV disease. Here, we studied carvacrol as a known immunomodulator on RSV infection outcome in a mice model.Materials and Methods:Balb/c mice were infected by intranasal inoculation of RSV-A2, and treatment started daily 24 h after infection. Mice were sacrificed on day five after infection and experimental analyses were performed to study airway immune cell influx, CD4 and CD8 subtypes, cytokine/chemokine secretion, lung histopathology, and viral load.Results:Results showed that using carvacrol enhanced immune cell influx, cytokine/chemokine production, and virus titer, and aggravated lung pathology. Our result showed that carvacrol administration increased viral titer compared to the RSVPBS group. Also, carvacrol significantly induced IFN-γ production and did not induce IL-10 production. Besides, carvacrol non-significantly increased lymphocytes and monocytes count but did not affect the neutrophil count.Conclusion:Carvacrol at the concentration of 80 (mg/kg) did not show immunomodulatory activity to alleviate the RSV infection outcome. Further research is needed to uncover the effects of the carvacrol intervention on virus replication and immune responses following RSV infection. Many herbal remedies in use contain carvacrol. However, the use of herbal remedies to treat viral respiratory infections such as RSV has to be performed with caution.

Oclacitinib, a Janus Kinase Inhibitor, Reduces the Frequency of IL-4- and IL-10-, but Not IFN-γ-, Producing Murine CD4+ and CD8+ T Cells and Counteracts the Induction of Type 1 Regulatory T Cells.

The purpose of the present study was to broaden the knowledge and understanding of the effects of oclacitinib (OCL), a Janus kinase inhibitor, on T cells in the context of both the immune mechanisms underlying anti-inflammatory and anti-allergic properties of the drug and its safety. The results indicate that beneficial effects of OCL in the treatment of skin allergic diseases may be partially mediated by the inhibition of IL-4 production in CD4+ and CD8+ T cells. To a certain extent, the antiproliferative effect of OCL on CD8+ T cells may also contribute to its therapeutic effect. The study found that OCL does not affect the proliferation of CD4+ T cells or the number of IFN-γ- and IL-17-producing CD4+ and CD8+ T cells. Moreover, OCL was found to counteract the induction of type 1 regulatory T (Tr1) cells and to act as a strong inhibitor of IL-10 production in both CD4+ and CD8+ T cells. Thus, these results indicate that beneficial effects of OCL in the treatment of skin allergic diseases are not mediated through: (a) the abolishment of IFN-γ and IL-17-production in CD4+ and CD8+ T cells; (b) generation of Tr1 cells; (c) inhibition of CD4+ T cell proliferation; (d) induction of IL-10 production in CD4+ T cells. The results of this study strongly suggest that, with respect to the evaluated parameters, OCL exerts a suppressive effect on Th2- but not Th1-mediated immunity.

TLR-9 Plays a Role in Mycobacterium leprae-Induced Innate Immune Activation of A549 Alveolar Epithelial Cells

The respiratory tract is considered the main port of entry of Mycobacterium leprae, the causative agent of leprosy. However, the great majority of individuals exposed to the leprosy bacillus will never manifest the disease due to their capacity to develop protective immunity. Besides acting as a physical barrier, airway epithelium cells are recognized as key players by initiating a local innate immune response that orchestrates subsequent adaptive immunity to control airborne infections. However, to date, studies exploring the interaction of M. leprae with the respiratory epithelium have been scarce. In this work, the capacity of M. leprae to immune activate human alveolar epithelial cells was investigated, demonstrating that M. leprae-infected A549 cells secrete significantly increased IL-8 that is dependent on NF-κB activation. M. leprae was also able to induce IL-8 production in human primary nasal epithelial cells. M. leprae-treated A549 cells also showed higher expression levels of human β-defensin-2 (hβD-2), MCP-1, MHC-II and the co-stimulatory molecule CD80. Furthermore, the TLR-9 antagonist inhibited both the secretion of IL-8 and NF-κB activation in response to M. leprae, indicating that bacterial DNA sensing by this Toll-like receptor constitutes an important innate immune pathway activated by the pathogen. Finally, evidence is presented suggesting that extracellular DNA molecules anchored to Hlp, a histone-like protein present on the M. leprae surface, constitute major TLR-9 ligands triggering this pathway. The ability of M. leprae to immune activate respiratory epithelial cells herein demonstrated may represent a very early event during infection that could possibly be essential to the generation of a protective response.

Effects of Kumaizasa (Sasa senanensis) Leaf Extract on Innate Immune Regulation in HEK293 Cells and Macrophages.

We investigated the effect of Kumaizasa leaf extract (KLE) on innate immunity using the HEK293 and RAW 264.7 cell lines. KLE, lipopolysaccharides (LPS), or KLE with LPS were added to RAW 264.7 cells. The TNF-α and IL-1β mRNA expression was then quantified. The expression of MAPKs, NFĸB, TNF-α and IL-1β proteins was also quantified. In addition, KLE was added to HEK293 cells and the IL-8 concentration was measured. In RAW 264.7 cells, KLE increased the levels of TNF-α and IL-1β mRNA. By contrast, when KLE and LPS were added to RAW 264.7 cells, the increase in TNF-α and IL-1β mRNA was ameliorated. Similarly, the expression of JNK and ERK proteins was reduced. The addition of KLE to HEK293 cells induced IL-8 production. Based on these results, a KLE-mediated mechanism may regulate immunity by suppressing the expression of JNK and ERK, which are involved in inflammatory signal transduction.

α1-Acid Glycoprotein Enhances the Immunosuppressive and Protumor Functions of Tumor-Associated Macrophages

Blood levels of acute-phase protein α1-acid glycoprotein (AGP, orosmucoid) increase in patients with cancer. Although AGP is produced from hepatocytes following stimulation by immune cell-derived cytokines under conditions of inflammation and tumorigenesis, the functions of AGP in tumorigenesis and tumor progression remain unknown. In the present study, we revealed that AGP contributes directly to tumor development by induction of programmed death ligand 1 (PD-L1) expression and IL6 production in macrophages. Stimulation of AGP induced PD-L1 expression in both human monocyte-derived macrophages through STAT1 activation, whereas AGP had no direct effect on PD-L1 expression in tumor cells. AGP also induced IL6 production from macrophages, which stimulated proliferation in tumor cells by IL6R-mediated activation of STAT3. Furthermore, administration of AGP to AGP KO mice phenocopied effects of tumor-associated macrophages (TAM) on tumor progression. AGP decreased IFNγ secretion from T cells and enhanced STAT3 activation in subcutaneous tumor tissues. In addition, AGP regulated PD-L1 expression and IL6 production in macrophages by binding with CD14, a coreceptor for Toll-like receptor 4 (TLR4), and inducing TLR4 signaling. These results provide the first evidence that AGP is directly involved in tumorigenesis by interacting with TAMs and that AGP might be a target molecule for anticancer therapy. SIGNIFICANCE: AGP-mediated suppression of antitumor immunity contributes to tumor progression by inducing PD-L1 expression and IL6 production in TAMs.

No pain, no gain: Sensory neurons heal a sunburn

In a recent issue of Nature, Hoeffel etal. describe a novel pathway of sterile tissue repair utilizing a mouse model of sunburn. This wound healing pathway is coordinated by sensory neuron-derived TAFA4 that induces IL-10 production from Tim4+ dermal macrophages to prevent sustained inflammation and the emergence of tissue fibrosis.

Inducible MyD88/CD40 (iMC) Costimulation Enhances Polyclonal Epstein-Barr Virus-Specific Cytotoxic T Lymphocyte (EBV-CTL) Proliferation and Anti-Tumor Activity

Introduction: Adoptive T cell transfer with antigen-specific cytotoxic T lymphocytes (CTLs) have shown promise for the treatment of cancer. Antitumor efficacy correlates with T cell expansion and persistence following infusion, suggesting that enhancing T cell proliferation and survival may increase the potency of T cell therapies. Here, we demonstrate that genetic modification of EBV-specific T cells with inducible MyD88/CD40 (iMC) provides user-controlled costimulation that amplifies IL-2 production, CTL proliferation and cytotoxicity against EBV-transformed B cells, suggesting that iMC may be used to augment EBV-CTL against EBV-associated malignancies.Methods: Peripheral blood mononuclear cells (PBMCs) from healthy donors were used to generate EBV lymphoblastoid cells (LCLs) by transforming B cells with B95-8 virus. EBV-CTL were subsequently generated by stimulating PBMCs with irradiated (40 Gy) autologous LCLs at a T cell to LCL ratio of 40:1 (day 0) and then subsequently expanded for an additional 2 weeks by restimulation (4:1 CTL:LCL ratio) in the presence of 50 U/ml IL-2. EBV-CTL were then transduced with bicistronic retroviral vectors encoding iMC and truncated CD19 (ΔCD19) (SFG-iMC-ΔCD19) or a control vector lacking the MC costimulatory domains (SFG-FKBP-ΔCD19). EBV specificity and transduction efficiency of EBV-CTL was assessed by EBV-specific dextramers and CD3+CD19+ expression by flow cytometry, respectively. In vitro antitumor activity and T cell proliferation was measured using a 7 day live cell imaging (IncuCyte) coculture assays with transduced EBV-CTL and autologous or HLA-disparate LCL with or without 1 nM rimiducid to activate the iMC costimulatory molecule at effector to target (E:T) ratios of 40:1, 20:1, and 10:1. Cytokine production was measured by ELISA.Results: EBV-CTL were successfully generated from EBV-seropositive donors and demonstrated specificity against EBV lytic antigens (EBNA3A; BZLF1) and showed specific recognition of autologous EBV-LCL, but not HLA-mismatched LCL. EBV-CTL were also efficiently transduced with iMC and control (FKBP) retroviral vectors (93% and 82%, respectively). Cytokine production (IL-2 and IL-6) by gene-modified EBV-CTL targeting autologous LCL was significantly enhanced by iMC activation with rimiducid (48-fold increase compared to FKBP-ΔCD19-transduced EBV-CTL and iMC-ΔCD19-transduced EBV-CTLs without rimiducid stimulation). In vitro live cell imaging demonstrated at high E:T ratios (40:1) that EBV-CTLs efficiently killed matched LCLs. However, at lower E:T ratios (20:1 and 10:1), only EBV-CTLs transduced with iMC-ΔCD19 and stimulated with rimiducid were able to control LCL outgrowth over 7 days, showing a 10-fold increase inhibition in tumor growth.Conclusion: iMC provides a flexible, costimulatory module that can be used to enhance EBV-specific CTL to increase anti-tumor activity. Activation of iMC with rimiducid, in combination with recognition of cognate EBV antigens, induces IL-2 production and promotes CTL proliferation and survival. These data suggest that genetic modification of EBV-CTL, or other virus or tumor-associate antigen-specific T cells, including tumor infiltrating lymphocytes (TILs), with iMC may provide necessary costimulation on demand to increase T cell proliferation and persistence leading to increased anti-tumor efficacy. DisclosuresKhalil:Bellicum Pharmaceuticals: Employment. Yvon:Bellicum Pharmaceuticals: Equity Ownership. Mahendravada:Bellicum Pharmaceuticals: Employment. Spencer:Bellicum Pharmaceuticals: Employment, Equity Ownership, Other: stockholders . Foster:Bellicum Pharmaceuticals: Employment, Other: stockholders .

Association between mucosal barrier disruption by Pseudomonas aeruginosa exoproteins and asthma in patients with chronic rhinosinusitis.

Chronic rhinosinusitis (CRS) is a common chronic respiratory condition, frequently associated with asthma and affecting the majority of cystic fibrosis (CF) patients. Pseudomonas aeruginosa infections and biofilms have been implicated in recalcitrant CRS. One of the mechanisms of action for bacteria in CRS and CF is mucosal barrier disruption by secreted products that contribute to the inflammation. However, the role of biofilm and planktonic forms of P. aeruginosa in this process is not known. The aim is to determine the effect of P. aeruginosa exoproteins isolated from CF and non-CF CRS patients on the mucosal barrier. Exoproteins from 40 P. aeruginosa isolates were collected in planktonic and biofilm forms and applied to air-liquid interface (ALI) cultures of primary human nasal epithelial cells (HNECs). Mucosal barrier integrity was evaluated by transepithelial electrical resistance (TEER), passage of FITC-dextrans and immunofluorescence of tight junction proteins. Cytotoxicity assays were performed to measure cell viability, and IL-6 ELISA was carried out to evaluate pro-inflammatory effects. Planktonic exoproteins from 20/40 (50%) clinical isolates had a significant detrimental effect on the barrier and significantly increased IL-6 production. Barrier disruption was characterized by a reduced TEER, increased permeability of FITC-dextrans and discontinuous immunolocalization of tight junction proteins and was significantly more prevalent in isolates harvested from patients with comorbid asthma (P<.05). Exoproteins from planktonic P. aeruginosa clinical isolates from asthmatic CRS patients have detrimental effects on the mucosal barrier and induce IL-6 production potentially contributing to the mucosal inflammation in CRS patients.

IgE-Binding Monocytes Have an Enhanced Ability to Produce IL-8 (CXCL8) in Animals with Naturally Occurring Allergy.

IL-8 is a potent chemokine that recruits neutrophils and basophils to promote inflammation in many species. IL-8 is produced by many cell types, including monocytes. In this study, we report a novel role for IgE-binding monocytes, a rare peripheral immune cell type, to promote allergic inflammation through IL-8 production in a horse model of natural IgE-mediated allergy. We developed a mAb with confirmed specificity for both recombinant and native equine IL-8 for flow cytometric analysis. Equine IL-8 was produced by CD14+/MHC class II+/CD16- monocytes, including a subpopulation of IgE-binding monocytes, following stimulation with LPS. In addition, IgE cross-linking induced IL-8 production by both peripheral blood basophils and IgE-binding monocytes. IL-8 production was compared between healthy horses and those with a naturally occurring IgE-mediated skin allergy, Culicoides hypersensitivity. Allergic horses had significantly higher percentages of IL-8+ IgE-binding monocytes after IgE cross-linking. In contrast, frequencies of IL-8+ basophils after IgE cross-linking were similar in all horses, regardless of allergic disease, highlighting IgE-binding monocytes as a novel source of IL-8 during allergy. We concluded that IgE-binding monocytes from allergic individuals have an increased capacity for IL-8 production and likely contribute to the recruitment of innate immune cells during IgE-mediated allergy and promotion of inflammation during repeated allergen contact.

Poly(I:C) enhances the efficacy of phagocytosis checkpoint blockade immunotherapy by inducing IL-6 production.

Macrophage phagocytosis plays essential roles in antitumor immunity. CD47/SIRPα phagocytosis checkpoint blockade has demonstrated therapeutic potential in several hematopoietic cancers, but recent clinical studies reported very limited efficacy against solid malignancies. Here, we show that polyinosinic-polycytidylic acid (Poly(I:C)), a synthetic analog of double-stranded RNA, enhances the antitumor activity of CD47 blockade in colorectal cancer in vitro and in vivo. Poly(I:C) activation leads to a potent immune response characterized by the production of proinflammatory cytokines, especially IL-6. Stimulation with IL-6 promotes the PI3K signaling and cytoskeletal reorganization required for macrophage phagocytosis mediated by CD47 blockade. Our findings demonstrate the potential of Poly(I:C) to synergize the efficacy of CD47 blockade therapy and a novel role for IL-6 in macrophage phagocytosis, which provide new strategy for combinational cancer immunotherapy.

Spike protein 1 of SARS‐CoV‐2 induces an immune and inflammatory response and increases expression of ACE2 in human endothelial cells

Introduction Interferon (IFN) alpha (IFNα) and lambda3 (IFNλ3) constitute the first line of immunity against viral infection by increasing expression of interferon-stimulated genes (ISGs). Both are produced in SARS-CoV-2 infection and have been considered therapeutically in COVID-19. In epithelial cells IFNs have been shown to influence the expression of angiotensin-converting enzyme 2 (ACE2), the receptor for S-protein (S1P) of SARS-CoV-2. ACE2 is part of the vascular renin angiotensin system and may be important in COVID-19-associated endotheliitis. Whether SP1 influences immune responses in endothelial cells unknown. We investigated effects of SP1 on ACE2 expression and immune responses in human endothelial cells. Methods Culturedhuman Microvascular, Lymphatic, Aortic and Pulmonary Endothelial Cells (MEC, LEC, AEC, and PEC respectively) were stimulated with SP1 of SARS-CoV-2 (1µg/106 cells), IFNα (100ng/mL) or IFNλ3 (100IU/mL). Because ACE2, metalloproteinase domain 17 (ADAM17) and type II transmembrane serine protease (TMPRSS2) are important for SARS-CoV-2 infection, cells were treated with inhibitors of ADAM17 (marimastat, 3.8nM and TAPI-1, 100nM), ACE2 (MLN4760, 440pM), and TMPRSS2 (camostat, 50µM). Expression of ISGs (ISG15, IFIT1, and MX1) was investigated by real-time PCR (5h), cytokine by ELISA and protein expression by immunoblotting (24h). Results AEC, LEC, MEC, and PEC stimulated with SP1 exhibited increased expression of ISGs: ISG15 (1.9-2.3-fold), IFIT1 (2.0-7.9-fold), MX1 (3.1-5.8-fold), indicating activation of the IFN pathway. MEC and LEC exhibited higher responses to IFNα activation. MEC (ISG15: 16-fold, IFIT1: 21-fold, MX1: 31-fold) and LEC (ISG15: 48-fold, IFIT1: 105-fold, MX1: 134-fold). Only MEC exhibited ISG expression induced by IFNλ3 (ISG15: 1.7-fold, IFIT1: 1.9-fold, MX1: 1.7-fold) (P<0.05). IL-6 production was increased in MEC stimulated with IFNα (1230pg/mL) and IFNλ3 (1124pg/mL) vs control (591pg/mL). Marimastat, but not camostat or MLN4760 inhibited SP1 effects. IFNα induced IL-6 production in AEC and PEC (178pg/mL vs control 109pg/mL). No changes in IL-6 were observed in LEC. IFNα increased expression of the short form of ACE2 (75kDa) (63%), ADAM17 (36%), and TMPRSS2 (65%) in MECs. This was associated with increased activation of pro-inflammatory pathways with increased phosphorylation of Stat1 (134%), Stat2 (102%), ERK1/2 (42%). IFNλ3 also increased phosphorylation of Stat2 (60%) and ERK1/2 (75%). In MEC, phosphorylation of the eNOS activation motif Ser1177 was reduced by IFNLα and (40%) and IFNλ3 (40%). Conclusions In human endothelial cells from multiple vascular beds, SP1, IFNα and IFNλ3 induced an immune response characterised by increased ISG expression and IL-6 production, processes that involve ADAM17. These effects were associated with increased expression of the short form of ACE2 and activation of pro-inflammatory pathways. Our novel findings demonstrate that SP-1 induces an endothelial immune and inflammatory response that may be important in endotheliitis associated with COVID-19.

Microneme Proteins 1 and 4 From Toxoplasma gondii Induce IL-10 Production by Macrophages Through TLR4 Endocytosis.

The protozoan parasite Toxoplasma gondii modulates host cell responses to favor its success in the early stage of infections by secreting proteins from its apical organelles. Some of these proteins, including microneme proteins (MICs) 1 and 4, trigger pro-inflammatory host cell responses. The lectins MIC1 and MIC4 interact with N-linked glycans on TLR2 and TLR4, activating NF-κB and producing IL-12, TNF-α, and IL-6. Interestingly, MIC1 and MIC4 also trigger secretion of the anti-inflammatory cytokine IL-10 through mechanisms as yet unknown. Herein, we show that the ability of these MICs to induce macrophages to produce IL-10 depends on TLR4 internalization from the cell surface. Macrophages subjected to blockade of endocytosis by Dynasore continued to release TNF-α, but failed to produce IL-10, in response to MIC1 or MIC4 exposure. Similarly, IL-10 was not produced by Dynasore-conditioned T. gondii-infected macrophages. Furthermore, MIC1- or MIC4-stimulated macrophages gained transient tolerance to LPS. We report a previously undiscovered mechanism by which well-defined T. gondii components inhibit a host inflammatory response.

Mutant glucocorticoid receptor binding elements on the interleukin-6 promoter regulate dexamethasone effects

BackgroundGlucocorticoids (GCs) have been extensively used as essential modulators in clinical infectious and inflammatory diseases. The GC receptor (GR) is a transcription factor belonging to the nuclear receptor family that regulates anti-inflammatory processes and releases pro-inflammatory cytokines, such as interleukin (IL)-6.ResultsFive putative GR binding sites and other transcriptional factor binding sites were identified on theIL-6 promoter, and dexamethasone (DEX) was noted to reduce the lipopolysaccharide (LPS)-induced IL-6 production. Among mutant transcriptional factor binding sites, nuclear factor-kappa B (NF-κB), activator protein (AP)-1, and specificity protein (Sp)1–2 sites reduced basal and LPS-induced IL-6 promoter activities through various responses. The second GR binding site (GR2) was noted to play a crucial role in both basal and inducible promoter activities in LPS-induced inflammation.ConclusionsWe concluded that selective GR2 modulator might exert agonistic and antagonistic effects and could activate crucial signaling pathways during the LPS-stimulated inflammatory process.