GM-CSF mRNA Levels Research Articles

Lipopolysaccharide regulation of antiinflammatory tristetraprolin family and proinflammatory gene expression in mouse macrophages

ObjectiveTristetraprolin (TTP/ZFP36) family proteins exhibit antiinflammatory effects by destabilizing proinflammatory mRNAs. Previous studies showed that bacterial endotoxin lipopolysaccharides (LPS) stimulated TTP and tumor necrosis factor (TNF) gene expression, but less was known about LPS effects on TTP homologues and other proinflammatory gene expression in macrophages. The objective was to investigate LPS regulation of TTP family gene and TTP-targeted gene expression in mouse RAW264.7 macrophages using much higher concentrations of LPS and much longer treatment time than previous studies.ResultsMTT assay showed that LPS was not toxic to the cells under LPS treatment up to 1000 ng/mL for 2–24 h. LPS mildly affected the soluble protein content in the cells. qPCR assay showed that LPS stimulated TTP mRNA rapidly but not sustainably with 40, 10, and 3 fold of the DMSO control after 2, 8 and 24 h treatment, respectively. Immunoblotting confirmed qPCR results on LPS stimulation of TTP gene expression in the mouse macrophages. LPS exhibited minimal effects on ZFP36L1, ZFP36L2 and ZFP36L3 mRNA levels. LPS increased mRNA levels of TNF, COX2, GM-CSF, INFγ and IL12b up to 311, 418, 11, 9 and 4 fold, respectively. This study demonstrated that LPS did not affect macrophage viability, dramatically increased antiinflammatory TTP gene expression as well as proinflammatory TNF and COX2 gene expression but had only mild effects on TTP homologues and other proinflammatory cytokine gene expression in the mouse macrophages.

MiR-193b-3p Regulates TLR4 Expression to Inhibit Inflammation by Targeting ETS1 in Allergic Rhinitis

Introduction: Allergic rhinitis (AR) is identified as a multifactorial disease caused by the interaction of genes and surroundings, which is difficult to cure. MicroRNAs were reported to be engaged in AR development. Here, we aimed to seek the anti-inflammatory effects and regulatory mechanism of miR-193b-3p in AR. Methods: Mucosal tissues from AR patients and healthy volunteers were collected, and human nasal epithelial cells (HNECs) were treated with IL-13 to establish a cell model of AR. The gene expression of miR-193b-3p, ETS1, TLR4, GM-CSF, eotaxin, and MUC5AC was determined by RT-qPCR. The protein levels of ETS1 and TLR4 were examined using Western blot. Enzyme-linked immunosorbent assay was performed to measure protein concentration of GM-CSF, eotaxin, and MUC5AC in cell supernatant. Dual luciferase assay was applied to verify the interaction among miR-193b-3p, ETS1, and TLR4. Results: The expression of miR-193b-3p was declined in clinical samples from AR patients and in IL-13-induced HNECs, while the mRNA and protein levels of ETS1 and TLR4 were elevated. MiR-193b-3p overexpression or ETS1 silencing notably decreased the mRNA and protein levels of GM-CSF, eotaxin, and MUC5AC in IL-13-treated HNECs. Mechanistically, miR-193b-3p directly combined with ETS1 to silence ETS1 expression. ETS1 promoted the transcriptional activity of TLR4 through interacting with TLR4 promoter. Furthermore, rescue experiments revealed that ETS1 overexpression abolished miR-193b-3p sufficiency-mediated suppression of the mRNA and protein levels of GM-CSF, eotaxin, and MUC5AC in IL-13-treated HNECs. Similarly, TLR4 overexpression compromised the inhibitory impacts of ETS1 downregulation on the mRNA and protein levels of GM-CSF, eotaxin, and MUC5AC in IL-13-induced HNECs. Discussion: MiR-193b-3p repressed IL-13-induced inflammatory response in HNECs by suppressing ETS1/TLR4 axis, which indicated that miR-193b-3p might be a therapeutic target for AR treatment.

Synergistic anti-cancer and attenuation effects of thymosin on chemotherapeutic drug vinorelbine in tumor-bearing zebrafish

Vinorelbine, the standard chemotherapy drug on advanced lung cancer, causes adverse events such as immunosuppression and bone marrow suppression. Thus, it is necessary to find drugs that could improve immune function and synergistically enhance the anti-tumor effect of vinorelbine. Thymosin is reported to inhibit tumor growth as an immunomodulator. Herein, to study the synergistic anti-cancer and attenuation effects of thymosin on vinorelbine, human lung cancer A549 cells that were labeled with CM-DiI were transplanted into zebrafish to establish the lung cancer xenotransplanted model. After treatment of vinorelbine and different concentrations of thymosin, the fluorescence intensity of CM-DiI-labeled A549 cells and the number of apoptotic muscle cells in the tumor-bearing zebrafish were detected. Besides, effects of thymosin on vinorelbine-reduced macrophages and T cells were identified in the transgenic zebrafish (Tg:zlyz-EGFP and Tg:rag2-DsRed). Then, the qRT-PCR was used to determine the alterations of the immune-related factors at the transcription level. Thymosin showed a marked synergistic anti-cancer effect with vinorelbine for the xenograft human lung cancer A549 cells, and the synergistic effect enhanced in a dose-dependent manner. Moreover, thymosin alleviated vinorelbine-induced muscle cell apoptosis, macrophage reduction, and T cell suppression. Compared with the vinorelbine group, co-administration with thymosin raised the mRNA levels of TNF-α, TNF-β, INF-γ, and GM-CSF. Thus, thymosin possesses synergistic anti-cancer effect on vinorelbine, and has protective effect on vinorelbine-induced immunosuppression. Thymosin, as an adjuvant immunomodulatory therapy, has great potential in enhancing the clinical application of vinorelbine.

Plant Polyphenol Gossypol Induced Cell Death and Its Association with Gene Expression in Mouse Macrophages

Gossypol is a complex plant polyphenol reported to be cytotoxic and anti-inflammatory, but little is known about its effect on gene expression in macrophages. The objective of this study was to explore gossypol's toxicity and its effect on gene expression involved in the inflammatory response, glucose transport and insulin signaling pathways in mouse macrophages. Mouse RAW264.7 macrophages were treated with multiple concentrations of gossypol for 2-24 h. Gossypol toxicity was estimated by MTT assay and soluble protein content. qPCR analyzed the expression of anti-inflammatory tristetraprolin family (TTP/ZFP36), proinflammatory cytokine, glucose transporter (GLUT) and insulin signaling genes. Cell viability was greatly reduced by gossypol, accompanied with a dramatic reduction in soluble protein content in the cells. Gossypol treatment resulted in an increase in TTP mRNA level by 6-20-fold and increased ZFP36L1, ZFP36L2 and ZFP36L3 mRNA levels by 26-69-fold. Gossypol increased proinflammatory cytokine TNF, COX2, GM-CSF, INFγ and IL12b mRNA levels up to 39-458-fold. Gossypol treatment upregulated mRNA levels of GLUT1, GLUT3 and GLUT4 genes as well as INSR, AKT1, PIK3R1 and LEPR, but not APP genes. This study demonstrated that gossypol induced macrophage death and reduced soluble protein content, which was accompanied with the massive stimulation of anti-inflammatory TTP family and proinflammatory cytokine gene expression, as well as the elevation of gene expression involved in glucose transport and the insulin signaling pathway in mouse macrophages.

Mitogen-activated protein kinase inhibitor PD98059 improves neuroimmune dysfunction in experimental autoimmune encephalomyelitis in SJL/J mice through the inhibition of nuclear factor-kappa B signaling in B cells

Multiple sclerosis (MS) is a severe autoimmune disease leading to demyelination, followed by consequent axonal degeneration, causing sensory, motor, cognitive, and visual symptoms. Experimental autoimmune encephalomyelitis (EAE) is the most well-studied animal model of MS. Most current MS treatments are not completely effective, and severe side effects remain a great challenge. In this study, we report the therapeutic efficacy of PD98059, a potent mitogen-activated protein kinase inhibitor, on proteolipid protein (PLP)139–151-induced EAE in SJL/J mice. Following the induction of EAE, mice were intraperitoneally treated with PD98059 (5 mg/kg for 14 days) daily from day 14 to day 28. This study investigated the effects of PD98059 on C-C motif chemokine receptor 6 (CCR6), CD14, NF-κB p65, IκBα, GM-CSF, iNOS, IL-6, TNF-α in CD45R+ B lymphocytes using flow cytometry. Furthermore, we analyzed the effect of PD98059 on CCR6, CD14, NF-κB p65, GM-CSF, iNOS, IL-6, and TNF-α mRNA and protein expression levels using qRT-PCR analysis in brain tissues. Mechanistic investigations revealed that PD98059-treated in mice with EAE had reduced CD45R+CCR6+, CD45R+CD14+, CD45R+NF-κB p65+, CD45R+GM-CSF+, CD45R+iNOS+, CD45R+IL-6+, and CD45R+TNF-α+ cells and increased CD45R+IκBα+ cells compared with vehicle-treated control mice in the spleen. Moreover, downregulation of CCR6, CD14, NF-κB p65, GM-CSF, iNOS, IL-6, and TNF-α mRNA expression level was observed in PD98059-treated mice with EAE compared with vehicle-treated control mice in the brain tissue. The results of this study demonstrate that PD98059 modulates inflammatory mediators through multiple cellular mechanisms. The results of this study suggest that PD98059 may be pursued as a therapeutic agent for the treatment of MS.

CCR1 antagonist J-113863 corrects the imbalance of pro- and anti-inflammatory cytokines in a SJL/J mouse model of relapsing-remitting multiple sclerosis

Multiple sclerosis (MS), an immune-mediated and neurodegenerative disorder of the central nervous system (CNS), is characterized by infiltrating myelin-reactive T lymphocytes and demyelinating lesions. Experimental autoimmune encephalomyelitis (EAE) is a well-established animal model used to study MS. To explore the impact of chemokine receptor CCR1 blockade in EAE and the underlying mechanisms, we used CCR1 antagonist J-113863 in PLP139-151-induced EAE in SJL/J mice. Following EAE induction, mice were treated with J-113863 (10 mg/kg) daily from day 14 until day 25. We investigated the effect of J-113863 on expression levels of GM-CSF, IL-6, IL-10, IL-27 in CD4+ spleen cells, using flow cytometry. We also analyzed the effect of J-113863 on GM-CSF, IL-6, IL-10, IL-27 mRNA and protein expression levels using RT-PCR and Western blot analysis in brain tissues. J-113863 treatment decreased the populations of CD4+GM-CSF+ and CD4+IL-6+ cells and increased CD4+IL-27+ and CD4+IL-10+ cells in the spleen. J-113863 had a suppressive effect on the mRNA and protein expression levels of GM-CSF, and IL-6 in the brain tissue. On the other hand, J-113863 treatment increased the mRNA and protein expression of IL-10 and IL-27 in the brain tissue. Our results highlighted J-113863′s potential role in suppressing pro-inflammatory expression and up-regulating anti-inflammatory mediators, which could represent a beneficial alternative approach to MS treatment.

Methylmercury chloride exposure aggravates proinflammatory mediators and Notch-1 signaling in CD14+ and CD40+ cells and is associated with imbalance of neuroimmune function in BTBR T+ Itpr3tf/J mice

Autism spectrum disorder (ASD) is a severe neurodevelopmental disorder characterized by deficits in social interaction, communication, and repetitive behaviors. A key role for immune dysfunction has been suggested in ASD. Recent studies have indicated that inflammatory mediators and Notch-1 signaling may contribute to the development of ASD. Methylmercury chloride (MeHgCl) is an environmental pollutant that primarily affects the central nervous system, causing neurological alterations. Its effects on immunological responses have not been fully investigated in ASD. In this study, we examined the influence of MeHgCl exposure on inflammatory mediators and Notch-1 signaling in BTBR T+ Itpr3tf/J (BTBR) mice, a model of ASD. We examined the effects of MeHgCl on the IL-6-, GM-CSF-, NF-κB p65-, Notch-1-, and IL-27-producing CD14+ and CD40+ cells in the spleen. We assessed the effect of MeHgCl on IL-6, GM-CSF, NF-κB p65, Notch-1, and IL-27 mRNA levels in brain tissue. We also measured IL-6, GM-CSF, and NF-κB p65 protein expression levels in brain tissue. MeHgCl exposure of BTBR mice significantly increased IL-6-, GM-CSF-, NF-κB p65-, and Notch-1-, and decreased IL-27-producing CD14+, and CD40+ cells in the spleen. MeHgCl exposure of BTBR mice upregulated IL-6, GM-CSF, NF-κB p65, and Notch-1, and decreased IL-27 mRNA expression levels in brain tissue. Moreover, MeHgCl resulted in elevated expression of the IL-6, GM-CSF, and NF-κB p65 proteins in brain tissue. Taken together, these results indicate that MeHgCl exposure aggravates proinflammatory mediators and Notch-1 signaling which are associated with imbalance of neuroimmune function in BTBR mice.

Involvement of CD45 cells in the development of autism spectrum disorder through dysregulation of granulocyte-macrophage colony-stimulating factor, key inflammatory cytokines, and transcription factors

Autismspectrum disorder (ASD) is a complex and multifactorial heterogeneous disorder. Previous investigations have revealed the association between the immune system and ASD, which is characterized by impaired communication skills. Inflammatory response through CD45 cells plays a key role in the pathogenesis of several autoimmune disorders; however, the molecular mechanism of CD45 cells in ASD is not clearly defined.In this study, we investigated the role of CD45 signaling in children with ASD. In this study, we aimed to investigate the possible involvement of CD45 cells expressing granulocyte-macrophage colony-stimulating factor and inflammatory transcription factors in ASD. Flow cytometric analysis, using peripheral blood mononuclear cells (PBMC), revealed the numbers of GM-CSF-, IFN-γ-, IL-6-, IL-9-, IL-22-, T-bet-, pStat3-, Helios-, and Stat6-producing CD45+ cells in children with ASD and children in the control group. We further evaluated the mRNA and protein expression levels of GM-CSF in PBMC by RT-PCR and western blotting analysis. Our results revealed that the children with ASD exhibited significantly higher numbers of CD45+GM-CSF+, CD45+IFN-γ+, CD45+IL-6+, CD45+IL-9+, CD45+IL-22+, CD45+T-bet+, and CD45+pStat3+ cells compared with the control group. We also found that the children with ASD showed a lower number of CD45+Helios+ and CD45+Stat6+ cells compared with the control group. Furthermore, the children with ASD showed higher GM-CSF mRNA and protein expression levels compared with the control group. These results indicated that CD45 could play an essential role in the immune abnormalities of ASD. Further investigation of the role of CD45 in neurodevelopment in ASD is warranted.

IRF8 represses GM-CSF expression in tumor cells to mediate myeloid-derived suppressor cell differentiation.

Abstract Myeloid-derived suppressive cells (MDSCs) are immature myeloid cells that are induced by inflammatory mediators. Massive accumulation of MDSCs is a hallmark of cancer in mice and human patients. Proinflammatory factors are believed to induce MDSC differentiation. In an early study, we showed that T cell-produced GM-CSF, a proinflammatory cytokine, induces MDSC accumulation under physiological conditions. We further determined that IRF8 represses MDSC accumulation in vivo. Tumor cells are known to produce abundant GM-CSF; we therefore sought to test the hypothesis that IRF8 regulates GM-CSF expression to mediate MDSC accumulation in the tumor-bearing host. We observed that mouse sarcoma cells rapidly induce MDSC accumulation, which is positively correlated with tumor growth kinetics. Analysis of purified MDSCs from tumor-bearing mice indicated that GM-CSF mRNA levels increase and IRF8 expression decreases as tumor sizes increase. GM-CSF and IRF8 expression kinetics are therefore inversely correlated in MDSCs in vivo. Analysis of the csf2 gene promoter DNA sequence identified an IRF8-binding consensus element, and ChIP analysis determined that IRF8 binds to this DNA element in the csf2 promoter. Analysis of human sarcoma specimens revealed that the IRF8 promoter DNA is hypermethylated. Silencing IRF8 expression using IRF8-specific shRNA increased GM-CSF expression. In summary, we determine that tumor cells use GM-CSF to induce MDSC differentiation, and IRF8 functions as a transcriptional repressor of GM-CSF expression to suppress MDSC accumulation. Human sarcoma cells may use DNA methylation to silence IRF8 and increase GM-CSF expression to promote MDSC accumulation, thereby suppressing the anti-tumor immune response.

Abstract A151: Radiation-induced TGFβ regulates the myeloid compartment to suppress antitumor immunity

Abstract One mechanism tumors use to evade immune responses is to regulate the abundance of myeloid-derived suppressor cells (MDSC), mainly through secreted factors (Gabrilovich and Nagaraj, 2009; Gabrilovich et al., 2012; Nagaraj and Gabrilovich, 2010). Here we examined whether this is affected by radiation therapy, which recent studies suggest can effectively prime anti-tumor immunity (Formenti and Demaria, 2012; Golden et al., 2012). In contrast, we have shown that radiation very efficiently activates TGFβ which is a suppressor of the adaptive immune response, particularly inhibiting T-cell activity and inducing T-regulatory cells. TGFβ also regulates innate immune response, particularly MDSC, which are a subset of immature myeloid precursors that are potent inhibitors of anti-tumor immunity. Here, we irradiated human breast cancer cell lines that were co-cultured with human monocytic precursors derived from circulating peripheral blood mononuclear cells (PBMC) isolated from healthy blood donors. CD14+ immature myeloid cells (IMC) stimulated with GM-CSF and IL-6 generated CD33+/CD11b+ MDSC with high efficiency (up to 90%). Consistent with the literature, TGFβ significantly promotes the accumulation of MDSC. IMC treated with TGFβ generated twice as many MDSC compared to the positive control of monocytes treated with alone (Mean = 18,509 -/+ 1523 cells (GM-CSF + IL-6 +TGFβ) vs 9010 -/+803.8 cells (GM-CSF + IL-6); N = 11 independent donors). Accordingly, small molecule TβRI inhibitor (LY 2109761) blocked this effect and further reduced by 50% the generation of MDSC compared to the GM-CSF and IL-6 positive control (Mean = 5371 -/+796.8 cells (GM-CSF + IL-6 + LY2109761 vs 9010 -/+803.8 cells (GM-CSF + IL-6); N = 11 independent donors). As reported (Lechner et al., 2010), tumor cell lines varied in their capacity to elicit MDSC from co-cultured IMC; being MCF7 less efficient than BT549, which are less efficient than MDA-MB-231. MDA-MB-231, which expresses higher levels of GM-CSF and IL-6 mRNA than the other cell lines, was used to test the effect of radiation. IMC were added to MDA-MB-231 monolayers irradiated with 5 Gy and co-cultured for 5 days in complete media (RPMI + 10% FBS). Tumor cell irradiation did not affect MDSC numbers but increased MDSC immunosuppressive capacity, as shown by a significant reduction in autologous CD8+ T-cell proliferation. This effect was TGFβ-dependent, as the immunosuppressive potential of MDSC was significantly reduced when they were generated in a context of TGFβ pathway inhibition. These results suggest that the combination of radiation therapy and inhibition of the TGFβ pathway may have a great therapeutic potential by releasing the suppressive action of MDSC on the anti-tumor immune responses. * This project has been funded through the Lilly Research Award Program (LRAP) Citation Format: Alba Gonzalez Junca, Ilenia Pellicciotta, Kyla Driscoll Carroll, David Schaer, Mary Helen Barcellos-Hoff. Radiation-induced TGFβ regulates the myeloid compartment to suppress antitumor immunity. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr A151.

98: TNF-induced pain requires local colony-stimulating factor (CSF)-1 signalling and systemic neutrophil infiltration

Pain is multifaceted. TNF has been implicated in the pathogenesis of arthritic pain but the relationship between TNF and other cell types during inflammatory pain is unknown. In the present study, we sought to determine the requirement for local colony-stimulating factor (CSF)-1 signalling, and local and/or systemic neutrophil involvement in TNF-driven pain development. Inflammatory pain was elicited by intraplantar injection of TNF- α into the left hindpaw and assessed for weight distribution change by incapacitance metre over a 24 h as an indication of pain. Local neutrophil depletion was performed by giving an intraplantar injection of anti-Ly6G mAb at the same time as TNF, while systemic neutrophil depletion was performed by giving an intraperitoneal injection of anti-Ly6G mAb two days prior to local injection of TNF. CSF-1 signalling was also blocked locally by giving an intraplantar injection of anti-CSF-1R mAb at the same time as TNF. For RT-PCR analysis, mice were sacrificed at 4hr and plantar skin tissue was collected for RNA extraction: MPO, TNF, IL-1 β and GM-CSF mRNA levels were measured. TNF-driven pain was transient, with maximal pain observed at 4 h. Anti-Ly6G mAb had no effect on TNF-evoked pain when it was co-injected with TNF, but systemic depletion of neutrophils using anti-Ly6G mAb abolished pain development, indicating the involvement of systemic neutrophil infiltration during TNF-induced pain. RT-PCR analysis revealed TNF-induced MPO, GM-CSF and IL-1 β mRNA gene expression were significantly reduced in mice pretreated with anti-Ly6G mAb. Intraplantar co-administration of the CSF-1R mAb with TNF also prevented pain development. Collectively this data shows that CSF-1 signalling in resident macrophages is required for TNF-induced pain development and systemic neutrophil infiltration is also required for TNF-induced pain development.

Autocrine GM-CSF transcription in the leukemic progenitor cell line KG1a is mediated by the transcription factor ETS1 and is negatively regulated through SECTM1 mediated ligation of CD7

BackgroundCD7 expression is found on ~30% of acute myeloblastic leukemias (AML). The leukemic progenitor cell line KG1a (CD7+) constitutively expresses GM-CSF while the parental KG1 (CD7-) cell line does not. This study focuses on the molecular basis of CD7 mediated GM-CSF regulation. MethodsKG1a cells were treated with recombinant SECTM1-Fc protein, the PI3K kinase inhibitors wortmannin, LY292004, or PI4K activator spermine. Stable KG1-CD7+, KG1a-shCD7, KG1a-shETS1 as well as KG1a-GFP, KG1a-PKCβII-GFP cell lines were generated and the levels of CD7, GM-CSF and ETS-1 mRNA and protein were compared by real-time-PCR, western blotting, flow cytometry and ELISA. ResultsSECTM1 is expressed in Human Bone Marrow Endothelial Cells (HBMEC) and its expression can be upregulated by both IFN-γ. KG1a cells demonstrated high expression levels of CD7 and ETS-1 allowing a constitutative signaling through the PI3K/Atk pathway to promote GM-CSF expression, while KG1 cells with low expression of CD7 and ETS-1 showed low GM-CSF expression. On KG1a cells GM-CSF expression could be negatively regulated by PI3K inhibitors or by recombinant SECTM1-Fc. Overexpression of CD7 in KG1 cells was insufficient to promote GM-CSF expression, while silencing of CD7 or ETS-1 resulted in reduced GM-CSF expression levels. Differentiation capable KG1a cells overexpressing PKCβII illustrated complete loss of CD7, but maintained normal levels of both ETS-1 and GM-CSF expression. ConclusionThese findings add an additional layer to the previously described autocrine/paracrine signaling between leukemic progenitor cells and the bone marrow microenvironment and highlight a role for SECTM1 in both normal and malignant hematopoiesis. General SignificanceThis work shows that SECTM1 secreted from bone marrow stromal cells may interact with CD7 to influence GM-CSF expression in leukemic cells.

Th17 cell LFA-1 engagement-mediated IL-17A and GM-CSF mRNA stabilization is HuR-dependent (54.14)

Abstract Recent studies demonstrate that the β2 integrin LFA-1 is required for entry of encephalitogenic Th17 cells into the brain parenchyma during murine experimental autoimmune encephalomyelitis (EAE). We previously showed that LFA-1 engagement by its ligand, intracellular adhesion molecule-1 (ICAM-1), in human T cells results in translocation of the RNA-binding protein HuR and stabilization of TNFα and IFNγ mRNAs. The role of HuR in the regulation of Th17 cell-mediated inflammation is unknown. We hypothesize that LFA-1 engagement in Th17 cells leads to increased neuropathology-relevant cytokine expression at inflammatory sites through HuR-mediated mRNA stabilization. LFA-1 engagement led to HuR nuclear-to-cytoplasmic translocation and stabilization of both IL-17A and GM-CSF transcripts in mouse EL4 T cells, in vitro differentiated mouse Th17 cells and human primary T cells. EL4 and human primary T cell adhesion to ICAM-1 led to increased levels of IL-17A and GM-CSF mRNA in HuR immunoprecipitates. LFA-1 engagement-stimulated IL-17A and GM-CSF mRNA stabilization was lost in HuR-deficient Th17 cells generated from RORcγt-Cre/HuRflox/flox mice. We conclude that LFA-1 engagement induces HuR-dependent stabilization of the otherwise labile GM-CSF and IL-17A transcripts in Th17 cells, and that this may be highly relevant in Th17 cell-induced CNS pathology. Future experiments will focus on the role of Th17 cell HuR in the EAE model.

Arsenic trioxide affects bone remodeling by effects on osteoblast differentiation and function

Arsenic trioxide (ATO) is widely used in tumor treatment, but excessive arsenic exposure can have adverse health effects. This study was to examine the association between ATO treatment and bone remodeling. The effects of ATO on osteoblast function were investigated in primary cell cultures and in an in vivo study in rats. Sprague–Dawley rats (n=30) were randomly assigned to 3 groups which were injected intraperitoneally with saline or 5 or 10mg/kg of ATO for 4weeks. In cell culture, ATO decreased osteoblast mineralization by decreasing alkaline phosphatase (ALP) expression and this effect was prevented by co-addition of inorganic phosphate (Pi). Moreover, levels of mRNAs for the transcription factors runt-related transcription factor 2 (Runx2) and osterix, the osteoblast osteogenic gene osteocalcin, and the adherence molecule vascular cell adhesion molecule-1 (VCAM-1) were decreased by ATO. Levels of mRNAs for the cytokine IL-6 were also decreased, whereas GM-CSF mRNA levels were increased. Similar effects of ATO on osteoblasts were seen in in vivo experiments in the rat. Moreover, decreases of bone turnover markers of osteocalcin, Procollagen type I N-terminal propeptide (PINP), and C-terminal cross-linked telopeptide (CTX) as well as bone mineral density (BMD) and trabecular bone volume of femur were observed in ATO-treated rats. These results suggest that ATO interferes with bone remodeling mostly through changes in osteoblast differentiation and function.

Decreased Neutrophil Apoptosis in Quiescent ANCA-Associated Systemic Vasculitis

BackgroundANCA-Associated Systemic Vasculitis (AASV) is characterized by leukocytoclasis, accumulation of unscavenged apoptotic and necrotic neutrophils in perivascular tissues. Dysregulation of neutrophil cell death may contribute directly to the pathogenesis of AASV.MethodsNeutrophils from Healthy Blood Donors (HBD), patients with AASV most in complete remission, Polycythemia Vera (PV), Systemic Lupus Erythematosus (SLE), Rheumatoid Arthritis (RA) and renal transplant recipients (TP) were incubated in vitro, and the rate of spontaneous apoptosis was measured by FACS. Plasma levels of cytokines and sFAS were measured with cytometric bead array and ELISA. Expression of pro/anti-apoptotic factors, transcription factors C/EBP-α, C/EBP-β and PU.1 and inhibitors of survival/JAK2-pathway were measured by real-time-PCR.ResultsAASV, PV and RA neutrophils had a significantly lower rate of apoptosis compared to HBD neutrophils (AASV 50±14% vs. HBD 64±11%, p<0.0001). In RA but not in AASV and PV, low apoptosis rate correlated with increased plasma levels of GM-CSF and high mRNA levels of anti-apoptotic factors Bcl-2A1 and Mcl-1. AASV patients had normal levels of G-CSF, GM-CSF and IL-3. Both C/EBP-α, C/EBP-β were significantly higher in neutrophils from AASV patients than HBD. Levels of sFAS were significantly higher in AASV compared to HBD.ConclusionNeutrophil apoptosis rates in vitro are decreased in AASV, RA and PV but mechanisms seem to differ. Increased mRNA levels of granulopoiesis-associated transcription factors and increased levels of sFAS in plasma were observed in AASV. Additional studies are required to define the mechanisms behind the decreased apoptosis rates, and possible connections with accumulation of dying neutrophils in regions of vascular lesions in AASV patients.

The effects of dexamethasone on cigarette smoke induced gene expression changes in COPD macrophages

Chronic obstructive pulmonary disease (COPD) is a smoking related inflammatory airway disease in which macrophages play a key role. Previously we have shown that cigarette smoke extract (CSE) causes suppression of macrophage inflammatory mediators, with the exception of IL-8. We now investigate the effects of dexamethasone on these gene expression changes. Monocyte derived macrophages (MDMs) were cultured with CSE and dexamethasone. Microarray analysis was used to assess inflammatory mediator regulation, with qPCR and ELISA also performed for selected cytokines. The major effect of CSE was down-regulation of inflammatory genes (11 probe sets). For CSE regulated genes ( n = 13), the median fold change with CSE alone was − 2.84 and with dexamethasone alone was − 2.97. Both treatments combined caused the greatest suppression of gene expression; − 4.47. qPCR also showed that IL-1β, GM-CSF and IL-6 mRNA levels were significantly reduced by CSE and further suppressed by dexamethasone. qPCR and ELISA showed that IL-8 levels were increased by CSE, with suppression by dexamethasone. We show that CSE suppressed the expression of some inflammatory genes whilst up-regulating IL-8. Dexamethasone further suppressed gene expression when combined with CSE. The combined effect of GC and CSE causes suppression of the macrophage innate immune response.

Tumor necrosis factor-alpha deficiency retards early fatty-streak lesion by influencing the expression of inflammatory factors in apoE-null mice

Tumor necrosis factor-alpha (TNF-α), a key inflammatory cytokine, plays an important role in atherosclerosis. However, its precise characters in primary stage of the disease remain unclear. To assess the influence of TNF-α on inflammatory factors in aorta and liver in apoE and TNF-α double mutant (AT) mice, a comparative study on early fatty-streak lesion, the mRNA level of target gene in aorta and liver of adolescent AT and apoE-null (apoE−/−) mice were achieved. The characteristics of expression of inflammatory factors, and early fatty-streak lesion relevance were analyzed. The plasma cytokines in 6-week-old AT and apoE−/− mice were also measured. Lipid accumulation in the intima of the aorta existed as early as 3 weeks of age in apoE−/− mice. Fatty-streak lesion was mild in AT mice but prominent in apoE−/− mice, at age of 6 weeks. Furthermore, most interesting findings indicate that mRNA levels of pro-atherosclerotic factors, i.e. IL-1β, IFN-γ, ICAM-1, VCAM-1, MCP-1, GM-CSF and NF-κB (p65) were significantly downregulated in AT mice. Whereas IL-2 and IκB-α were upregulated in aorta of AT mice versus those in apoE−/− mice (p<0.01) and the transcript levels of pro-inflammatory cytokines, such as IL-1β, IFN-γ, ICAM-1, VCAM-1, MCP-1 and GM-CSF, increased with atherogenesis progression. On the other hand, the expression of these inflammatory factors in the liver displayed somewhat similar fashion to those in the aorta. Moreover, the plasma lipids profile in AT mice showed less pro-atherogenic than that of apoE−/− mice. Our data indicated that TNF-α deficiency surely, although not completely, retards fatty-streak lesion formation due to downregulated expression of the pro-atherosclerotic inflammatory factors in the present circumstance.

Effects of a Combination of Thyme and Oregano Essential Oils on TNBS-Induced Colitis in Mice

We examined the anti-inflammatory effects of the combination of thyme and oregano essential oil dietary administered at three concentrations (0.4% thyme and 0.2% oregano oils; 0.2% thyme and 0.1% oregano oils; 0.1% thyme and 0.05% oregano oils) on mice with TNBS-induced colitis. Treatment of colitic animals with the essential oils decreased the mRNA levels of pro-inflammatory cytokines IL-1, IL-6, GM-CSF, and TNF, especially after application of the medium dose. The medium dose of the essential oils significantly lowered the amount of IL-1 and IL-6 proteins too. Moreover, administration of the medium dose decreased the mortality rate, accelerated the body weight gain recovery, and reduced the macroscopic damage of the colonic tissue. Our results indicate that combined treatment with appropriate concentrations of thyme and oregano essential oils can reduce the production of proinflammatory cytokines, and thereby attenuate TNBS-induced colitis in mice.

Adiponectin stimulates proliferation and cytokine secretion in colonic epithelial cells

Adiponectin is a recently described mediator secreted by adipose tissue. Here we report the growth promoting and pro-inflammatory actions of adiponectin on colonic epithelial cancer cells. Full-length and globular adiponectin produced an identical stimulation of HT-29 cell growth that was blocked by inhibition of adenylate cyclase and protein kinase A and partially inhibited by a pan-specific protein kinase C inhibitor, but was unaffected by specific inhibition of extracellular signal-related kinase (ERK) or p38 MAP kinase. Globular adiponectin but not full-length adiponectin significantly increased the secretion and mRNA levels of IL-8, GM-CSF and MCP-1. Globular adiponectin doubled IL-1β-stimulated IL-8 and GM-CSF secretion. Adiponectin-stimulated cytokine secretion was blocked by pharmacological inhibitors of NF-κB, ERK and p38 MAP kinase. Globular adiponectin increased phosphorylation of both ERK and p38 MAP kinase and increased the nuclear translocation of active NF-κB. Adiponectin has pro-proliferative and pro-inflammatory actions on colonic epithelial cells; these appear to be differentially activated by the adiponectin isoforms. Adiponectin may have a role in the regulation of gastrointestinal mucosal function, inflammation and colon carcinogenesis.

Enhanced IgE allergic response to Aspergillus fumigatus in CFTR−/− mice

To gain insight into aberrant cytokine regulation in cystic fibrosis (CF), we compared the phenotypic manifestations of allergen challenge in gut-corrected CFTR-deficient mice with background-matched C57Bl6 (B6) mice. Aspergillus fumigatus (Af) antigen was used to mimic allergic bronchopulmonary aspergillosis, a peculiar hyper-IgE syndrome with a high prevalence in CF patients. CFTR−/−, C57BL/6 and FVB/NJ mice were sensitized with Af antigen by serial intraperitoneal injections. Control mice were mock sensitized with PBS. Challenges were performed by inhalation of Af antigen aerosol. After Af antigen challenge, histologic analysis showed goblet cell hyperplasia and lymphocytic infiltration in both strains. However, total serum IgE levels were markedly elevated in CF mice. Sensitized CF mice showed a five-fold greater IgE response to sensitization as compared with B6- and FVB-sensitized controls. Additional littermate controls to fully normalize for B6-FVB admixture in the strain background confirmed the role of CFTR mutation in the hyper-IgE syndrome. Cytokine mRNA levels of IL-5 and GM-CSF in the bronchoalveolar lavage (BAL) fluid, and BAL cell differentials indicated that CFTR mutation caused a shift from an IL-5-predominant to an IL-4-predominant cytokine profile. This system models a very specific type of airway inflammation in CF and could provide insights into pathogenesis and treatment of the disease.