scholarly journals Klf4 Alleviates Lipopolysaccharide-Induced Inflammation by Inducing Expression of MCP-1 Induced Protein 1 to Deubiquitinate TRAF6

2018 ◽  
Vol 47 (6) ◽  
pp. 2278-2290 ◽  
Author(s):  
Zhenzhen Li ◽  
Yanhui Jia ◽  
Shichao Han ◽  
Xingqin Wang ◽  
Fu Han ◽  
...  

Background/Aims: Inflammation is an essential component of innate immunity against pathogens, but is tightly regulated, such as by Krüppel-like factor 4 (Klf4), to prevent injury. Klf4 also regulates macrophage polarization, although the mechanisms underlying both functions are poorly understood. The aim of this study was to investigate whether and how Klf4 prevents unregulated inflammation. Methods: The bone marrow-derived macrophages and RAW264.7 cell line were used. Quantitative real-time PCR was used to determine inflammatory cytokines (IL-1β, TNF-α, IL-6 and MCP-1), Klf4 and MCPIP1 transcript levels. Extraction of nuclear and cytoplasmic proteins and Immunoblotting were used to determine Klf4, MCPIP1, relative kinases from NF-κB pathway and K63-linked polyubiquitins expression in nucleus and cytoplasm separately. Dual luciferase reporter assay was used to analyze whether Klf4 mediate MCPIP1 transcription. Immunoprecipitation was used to determine the protein interaction among Klf4, MCPIP1, TRAF6 and K63-linked polyubiquitins. Secretion of IL-1β and TNF-α into sera in mice was measured by Enzyme-linked immunosorbent assay. Results: We found that exposure to lipopolysaccharides suppresses Klf4 expression, even as it induces release of pro-inflammatory cytokines. Strikingly, Klf4 overexpression significantly lowered cytokine secretion and NF-κB signaling in the cytoplasm following exposure to lipopolysaccharide, even though Klf4 was exclusively nuclear. The cytoplasmic effects are likely mediated by MCP-1 induced protein 1 (MCPIP1), a deubiquitinase and a key modulator of inflammation that accumulates both in the nucleus and cytoplasm in response to Klf4. Indeed, binding between MCPIP1 and K63 polyubiquitins is attenuated in macrophages overexpressing Klf4, suggesting that MCPIP1 is an intermediator induced by Klf4 in the nucleus to remove K63 polyubiquitins from TRAF6 in the cytoplasm, and thereby impede NF-κB and inflammatory signaling. Importantly, Klf4 overexpression in mice alleviated sepsis symptoms following exposure to lipopolysaccharides. Conclusion: The data highlight Klf4 as an essential MCPIP1-dependent modulator of innate immunity that protects against excessive and self-destructive inflammation.

2021 ◽  
pp. 1-11
Author(s):  
Jun Dong ◽  
Tingkai Fu ◽  
Yunxue Yang ◽  
Zhenxin Mu ◽  
Xingang Li

<b><i>Introduction:</i></b> Long noncoding RNA small nuclear host gene 1 (SNHG1) was involved in neuroinflammation in microglial BV-2 cells; however, its interaction with microRNA (miR)-181b in lipopolysaccharide (LPS)-induced BV-2 cells remained poor. <b><i>Methods:</i></b> BV-2 cells were treated with LPS and then were subjected to observation on morphology and immunofluorescence staining. After transfection, levels of inflammatory cytokines interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) were determined with enzyme-linked immunosorbent assay (ELISA). The potential binding sites between SNHG1 and miR-181b were confirmed using dual-luciferase reporter assay. Quantitative real-time polymerase chain reaction and Western blot were applied for detecting the mRNA and protein expressions of proinflammatory cytokines, ionized calcium-binding adapter molecule 1 (Iba1), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). <b><i>Results:</i></b> LPS led to the morphological changes and activation of BV-2 cells. The transfection of SNHG1 overexpression vector further promoted LPS-induced SNHG1 upregulation, inflammatory cytokines (IL-1β, IL-6, and TNF-α) generation and Iba-1, COX-2, and iNOS expressions, whereas silencing SNHG1 did the opposite. miR-181b functions as a downstream miRNA of SNHG1. In LPS-treated cells, the inhibition of miR-181b induced by SNHG1 promoted inflammation response and the expressions of Iba-1, COX-2, and iNOS. <b><i>Conclusion:</i></b> SNHG1 was involved in LPS-induced microglial activation and inflammation response via targeting miR-181b, providing another evidence of the roles of SNHG1 implicated in neuroinflammation of microglia.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shengchao Zhang ◽  
Jiankai Fang ◽  
Zhanhong Liu ◽  
Pengbo Hou ◽  
Lijuan Cao ◽  
...  

Abstract Background Muscle stem cells (MuSCs) are absolutely required for the formation, repair, and regeneration of skeletal muscle tissue. Increasing evidence demonstrated that tissue stem cells, especially mesenchymal stem cells (MSCs), can exert therapeutic effects on various degenerative and inflammatory disorders based on their immunoregulatory properties. Human mesenchymal stem cells (hMSCs) treated with interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) were reported to possess anti-inflammatory functions by producing TNF-stimulated gene 6 (TSG-6). However, whether human muscle stem cells (hMuSCs) also possess TSG-6 mediated anti-inflammatory functions has not been explored. Methods The ulcerative colitis mouse model was established by subjecting mice to dextran sulfate sodium (DSS) in drinking water for 7 days. hMuSCs were pretreated with IFN-γ and TNF-α for 48 h and were then transplanted intravenously at day 2 of DSS administration. Body weights were monitored daily. Indoleamine 2,3-dioxygenase (IDO) and TSG-6 in hMuSCs were knocked down with short hairpin RNA (shRNA) and small interfering RNA (siRNA), respectively. Colon tissues were collected for length measurement and histopathological examination. The serum level of IL-6 in mice was measured by enzyme-linked immunosorbent assay (ELISA). Real-time PCR and Western blot analysis were performed to evaluate gene expression. Results hMuSCs treated with inflammatory factors significantly ameliorated inflammatory bowel disease (IBD) symptoms. IDO and TSG-6 were greatly upregulated and required for the beneficial effects of hMuSCs on IBD. Mechanistically, the tryptophan metabolites, kynurenine (KYN) or kynurenic acid (KYNA) produced by IDO, augmented the expression of TSG-6 through activating their common receptor aryl hydrocarbon receptor (AHR). Conclusion Inflammatory cytokines-treated hMuSCs can alleviate DSS-induced colitis through IDO-mediated TSG-6 production.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yang Chen ◽  
Zhengyang Huang ◽  
Bin Wang ◽  
Qinming Yu ◽  
Ran Liu ◽  
...  

Retinoic acid-inducible gene I- (RIG-I-) like receptors (RLRs) have recently been identified as cytoplasmic sensors for viral RNA. RIG-I, a member of RLRs family, plays an important role in innate immunity. Although previous investigations have proved that RIG-I is absent in chickens, it remains largely unknown whether the chicken can respond to RIG-I ligand. In this study, the eukaryotic expression vectors encoding duRIG-I full length (duck RIG-I, containing all domains), duRIG-I N-terminal (containing the two caspase activation and recruitment domain, CARDs), and duRIG-I C-terminal (containing helicase and regulatory domains) labeled with 6*His tags were constructed successfully and detected by western blotting. Luciferase reporter assay and enzyme-linked immunosorbent assay (ELISA) detected the duRIG-I significantly activated NF-κB and induced the expression of IFN-βwhen polyinosinic-polycytidylic acid (poly[I:C], synthetic double-stranded RNA) challenges chicken embryonic fibroblasts cells (DF1 cells), while the duRIG-I was inactive in the absence of poly[I:C]. Further analysis revealed that the CARDs (duRIG-I-N) induced IFN-βproduction regardless of the presence of poly[I:C], while the CARD-lacking duRIG-I (duRIG-I-C) was not capable of activating downstream signals. These results indicate that duRIG-I CARD domain plays an important role in the induction of IFN-βand provide a basis for further studying the function of RIG-I in avian innate immunity.


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 926.3-926
Author(s):  
R. Dhahri ◽  
A. Dghaies ◽  
M. Slouma ◽  
L. Metoui ◽  
I. Gharsallah ◽  
...  

Background:Common low back pain (LBP) is a common health problem affecting 50 to 80% of working age adults. It is one of the common and costly health problems in Tunisia. Actually, the role of the immune response and inflammatory cytokines in the pathogenesis of chronic pain has been of growing interest.Objectives:The aim of this study was to assess whether pro and anti-inflammatory cytokines could be detected in serum in patients with LBP compared with healthy subjects and whether they could be related to pain severity and to clinical findings.Methods:It was a an analytical cross-sectional study including 50 patients with at least three months of LBP, in the department of rheumatology, orthopedics and immunology at the Military Hospital of Tunis between January 1st and March 31, 2020. All patients had a standardized clinical assessment.Levels of serum cytokines IL-6, IL-8, IL-1β and TNF- α, were measured using the chimiluminescence technique. Serum concentration of IL-10 was assayed by the enzyme-linked immunosorbent assay technique (ELISA). The normal levels of cytokines were determined in 50 healthy controls.Results:The mean age of the patients was 41.9 ± 8.4 years and the sex ratio was 4.5. LBP duration was 66.4 months. The mean lumbar visual analog scale (VAS) was 4.5 ± 1.9, and the root VAS was 2.6 ± 2.5. Neuropathic pain was found in 26% of patients. The average BMI was 27 ± 3.7 kg/m2. Only serum level of IL-8 was significantly higher in subjects with LBP compared to healthy controls (p <10-3). IL-1β was indetectable in both patients and controls. Positive correlations were found between IL-8 levels and anxiety/functional scores (r = 0.3; p = 0.02/ r = 0.3; p = 0.04). IL-6 was positively correlated with BMI, and negatively correlated with the Schober test. No correlations were found between serum levels of IL-6, IL-8, IL-10, TNF-α and pain intensity (VAS), neuropathic pain (DN4), fibromyalgia (FIRST), depression (HAD) and various radiological data.Conclusion:Interleukin-8 is a biomarker of common low back pain and correlate with anxiety and functional disability. These results suggest that IL-8 may be a therapeutic target to reduce chronic back pain and reduce the social and profession impact.Disclosure of Interests:None declared


2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Hector A Cabrera-Fuentes ◽  
Klaus T Preissner ◽  
William A Boisvert

As an important component of atherosclerosis, monocytes/macrophages respond to external stimuli with rapid changes in their expression of many inflammation-related genes to undergo polarization towards the M1 (pro-inflammatory) or M2 (anti-inflammatory) phenotype. Although sialoadhesin (Sn), also known as SIGLEC-1 or CD169, is a transmembrane protein receptor expressed on monocytes and macrophages whether it has a role in macrophage polarization and ultimately, macrophage-driven atherogenesis, has not been investigated. We have previously shown that, independently of Toll-like receptor signaling, extracellular RNA (eRNA) could exert pro-thrombotic and pro-inflammatory properties in the cardiovascular system by inducing cytokine mobilization. In the current study, recombinant mouse macrophage CSF[[Unable to Display Character: &#8211;]]driven bone marrow-derived macrophage (BMDM) differentiation was found to be skewed towards the M1 phenotype by exposure of cells to eRNA. This resulted in up-regulation of inflammatory markers, whereas anti-inflammatory genes were significantly down-regulated by eRNA. Interestingly, eRNA was released from BMDM under hypoxia and induced TNF-α liberation by activating TNF-α converting enzyme (TACE) to provoke inflammation. Conversely, TNF-α promoted eRNA release, especially under hypoxia, feeding a vicious cycle of cell damage. Administration of RNase1 or TAPI (a TACE-inhibitor) prevented the production of inflammatory mediators. Murine BMDM isolated from mice deficient in sialoadhesin had the opposite reaction to eRNA treatment with a prominent down-regulation of pro-inflammatory cytokines/M1 phenotype markers, while anti-inflammatory cytokines/M2 phenotype markers were significantly raised. In keeping with the proposed role of eRNA as a pro-inflammatory “alarm signal”, these data further shed light on the role of eRNA in macrophage function in the context of chronic inflammatory diseases such as atherosclerosis. The identification of sialoadhesin as putative eRNA recognition site on macrophages may allow further investigation of the underlying mechanisms of eRNA-macrophage interaction and related signal transduction pathways. Siglec-1 thereby may provides a new target to treat eRNA-mediated vascular diseases.


2006 ◽  
Vol 74 (9) ◽  
pp. 5211-5220 ◽  
Author(s):  
Kazuhisa Ouhara ◽  
Hitoshi Komatsuzawa ◽  
Hideki Shiba ◽  
Yushi Uchida ◽  
Toshihisa Kawai ◽  
...  

ABSTRACT Antimicrobial peptides, human β-defensin (hBD), and the 18-kDa cationic antimicrobial protein (CAP18) are components of innate immunity. These peptides have antimicrobial activity against bacteria, fungi, and viruses. Actinobacillus actinomycetemcomitans is a gram-negative facultative anaerobe implicated in the initiation of periodontitis. The innate immunity peptides have antibacterial activity against A. actinomycetemcomitans. We investigated the molecular mechanism of human gingival epithelial cells (HGEC) responding to exposure to A. actinomycetemcomitans. HGEC constitutively express hBD1 and inducibly express hBD2, hBD3, and CAP18 on exposure to A. actinomycetemcomitans. The level of expression varies among clinical isolates. In the signaling pathway for hBD2 induction by the bacterial contact, we demonstrate that the mitogen-activated protein (MAP) kinase and not the NF-κB transcription factor pathway is used. We found the outer membrane protein 100 (Omp100; identified by molecular mass) is the component inducing the hBD2 response. Omp100 binds to fibronectin, an extracellular matrix inducing hBD2 via the MAP kinase pathway. Anti-integrin α5β1, antifibronectin, genistein, and PP2 suppress the Omp100-induced expression of hBD2, suggesting that Src kinase is involved through integrin α5β1. The inflammatory cytokines, tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), IL-6 and IL-8, produced by HGEC on contact with A. actinomycetemcomitans also stimulate expression of hBD2. Further, neutralizing antibody against TNF-α or IL-8 partially inhibits the induction of hBD2 on bacterial contact. Therefore, we found that the induction of the antimicrobial peptides is mediated by a direct response principally through an Omp100-fibronectin interaction, and using secondary stimulation by inflammatory cytokines induced by the bacterial exposure.


2018 ◽  
Vol 105 (2) ◽  
pp. 116-126 ◽  
Author(s):  
M Rajabi ◽  
G Mohaddes ◽  
F Farajdokht ◽  
S Nayebi Rad ◽  
M Mesgari ◽  
...  

Behavioral disturbances are observed in most patients suffering from diabetes. According to some evidence, pro-inflammatory cytokines have a key role both in diabetes and behavioral disorders, such as anxiety and depression. In this study, the effect of chronic administration of loganin, as a bioflavonoid, was investigated on pro-inflammatory cytokines and depression- and anxiety-like behaviors in streptozotocin-induced diabetes in male Wistar rats. Blood levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were assessed by enzyme-linked immunosorbent assay method. Depression- and anxiety-like behaviors were evaluated by forced swimming test (FST), elevated plus maze (EPM), and open field test (OFT), respectively. Body weight was also measured before the interventions and after the experiments in all groups. Our findings show that loganin-treated animals had significantly lower serum concentrations of IL-6 and TNF-α compared with the diabetic group. In the EPM test, loganin treatment significantly increased the percentage of the open arm time and open arm entries. Moreover, loganin treatment significantly decreased the grooming time and restored distance traveled and center crossing in the OFT. However, it decreased immobility time in the FST. Loganin treatment also significantly restored body weight gain and attenuated blood glucose changes in the diabetic rats. These results indicate that loganin possibly alleviates depression- and anxiety-like behaviors associated with diabetes through lowering the blood glucose and pro-inflammatory cytokine levels. More research is required to show the exact mechanism of antidepressant and anxiolytic effects of loganin in diabetes.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1096-1096
Author(s):  
Wulin Aerbajinai ◽  
Kyung Chin ◽  
Jianqiong Zhu ◽  
Griffin P Rodgers

Abstract Abstract 1096 The macrophage-mediated inflammatory response plays a critical role in the development of obesity-related tissue inflammation and insulin resistance. Free-fatty acids (FFAs) are well-characterized factors causing production of inflammatory factors and insulin resistance. Glia maturation factor-gamma (GMFG), a member of the ADF/cofilin family of proteins that regulate actin cytoskeleton reorganization, is preferentially expressed in inflammatory cells, but its function in the macrophages immune response remains unclear. In this study, we investigated whether GMFG may affect FFAs-induced inflammatory reaction in macrophages. We show here that silencing of GMFG (80% inhibition of the endogenous expression levels) by transfected with GMFG siRNA significantly enhanced FFAs-induced production of proinflammatory cytokines and chemokines, including TNF-α, IL-6 and IL-8 compared to transfected non-targeting silencing siRNA in human peripheral blood monocytes-derived macrophage (1.2 × 104 ± 224.2 vs. 4.6 × 103 ± 98.4 molecules/ng, P < 0.001; 1.2 × 103 ± 56.1 vs. 2.3 × 102 ± 8.4 molecules/ng, P =0.001; 1.3 × 107 ± 5.8 × 105 vs. 4.9 × 106 ± 2.8 × 105 molecules/ng, P < 0.001) as determined by quantitative real time-PCR and confirmed by enzyme-linked immunosorbent assay (TNF-α: 9.4 × 102 ± 38.6 vs. 5.6 × 102 ± 31.1 ng/mL, P < 0.01; IL-6: 4.5 × 102 ± 31.3 vs. 2.2 × 102 ± 22.7 ng/mL, P < 0.01; IL-8: 2.2 × 103 ± 205.5 vs. 1.3 × 103 ± 113.9 ng/mL, P < 0.01). These increased inflammatory cytokines resulted from an increased activation of NF-κB and the ERK1/2 MAPK signaling pathway (based on increased NF-κB p65 phosphorylation, IκBα loss and enhanced phosphorylation of ERK1/2 in Western blot analysis) and a reduced phosphorylation of the PI3K/Akt/GSK3-β pathway following FFAs stimulation. Overexpression of GFP-GMFG in GMFG-silenced cells abrogated enhanced phosphorylation of NF-κB p65, ERK1/2 MAPK and reduced phosphorylation of Akt and GSK3-β. Furthermore, in cells in which GMFG was knockdown, FFAs induced an increase in the expression of SHIP1, a phosphatase that negatively regulates the PI3K signaling pathway, suggesting increased SHIP1 expression may be responsible for the augmentation of inflammatory cytokines following FFAs stimulation. We also show that silencing of GMFG enhances the oxidized low density lipoprotein (oxLDL) induced expression of TNF-α and IL-6 (2.9 × 104 ± 204.8 vs. 1.3 × 104 ± 153.9 molecules/ng, P < 0.01; 2.5 × 103 ± 31.3 vs. 9.2 × 102 ± 22.7 ng/mL, P < 0.01) in MDM. Taking together with the data that GMFG is constitutively expressed in macrophages and its expression is down-regulated by FFAs stimulation, GMFG might function as a novel negative regulator through participating in the PI3K/Akt signaling pathway, suggesting that macrophage-specific modulation of GMFG may be beneficial in the treatment of FFAs induced inflammation. Disclosures: No relevant conflicts of interest to declare.


2020 ◽  
Author(s):  
Jin Xu ◽  
Xiaozhong Qian ◽  
Ren Ding

Abstract Background: Osteoarthritis (OA) is a chronic and degenerative joint disease prevalent in the elderly. MiR-24-3p has been reported to be involved in an OA-resembling environment. However, the functional role and underlying mechanism of miR-24-3p in chondrocyte injury associated with OA remains unknown. Methods: The expression of miR-24-3p was determined in OA cases and control patients, as well as IL-1β-stimulated chondrocyte cell line CHON-001 using reverse transcription quantitative PCR analysis. Cell viability was analyzed by CCK-8 assay. Apoptosis status was assessed by caspase-3 activity detection. The pro-inflammatory cytokines (TNF-α and IL-18) were determined using ELISA assay. The association between miR-24-3p and BCL2L12 was confirmed by luciferase reporter assay.Results: We first observed that miR-24-3p expression level was lower in the OA cases than in the control patients and IL-1β decreased the expression of miR-24-3p in the chondrocyte CHON-001. Functionally, overexpression of miR-24-3p significantly attenuated IL-1β-induced chondrocyte injury, as reflected by increased cell viability, decreased caspase-3 activity, pro-inflammatory cytokines (TNF-α and IL-18). Western blot analysis showed that overexpression of miR-24-3p weakened IL-1β-induced cartilage degradation, as reflected by reduction of MMP13 (Matrix Metalloproteinase-13) and ADAMTS5 (A Disintegrin And Metalloproteinase with Thrombospondin Motifs-5) protein expression, as well as markedly elevation of COL2A1 (collagen type II). Importantly, BCL2L12 was demonstrated to be a target of miR-24-3p. BCL2L12 knockdown imitated, while overexpression significantly abrogated the protective effects of miR-24-3p against IL-1β-induced chondrocyte injury.Conclusions: In conclusion, our work provides important insight into targeting miR-24-3p/BCL2L12 axis in OA therapy.


PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242152
Author(s):  
Sonia Hammami ◽  
Imen Ghzaiel ◽  
Souha Hammouda ◽  
Nabil Sakly ◽  
Mohamed Hammami ◽  
...  

The present study was undertaken to evaluate serum levels of pro-inflammatory cytokines in Tunisian older adults and to examine the relationships between inflammatory marker levels, geriatric, and biochemical parameters. A cross-sectional study was conducted in a population of Tunisian older adults (N = 141, aged 65 and over). Patients were recruited from the Department of Internal Medicine, Fattouma Bourguiba University Hospital (Monastir, Tunisia) and from a nursing home (Sousse, Tunisia). Comprehensive geriatric assessment, history taking and examination including functional and nutritional assessment were done for each participant. Enzyme-linked immunosorbent assay (ELISA) test was used to measure serum cytokine (TNF-α, IL-8, IL-6) levels. The modified Short Emergency Geriatric Assessment score (SEGAm) were used to classify patients as 51 very-frail, 40 frail, and 50 non-frail. The age of the participants (80 men, 61 women) ranged from 65 to 97 years. Serum levels of TNF-α, IL-8 and C-reactive protein (CRP) were significantly higher in very-frail participants compared to frail and non-frail ones. However, no significant differences in IL-6 levels were detected among frailty groups. After adjustment for age, CRP and IL-8 levels remained significantly associated with frailty. Analysis of the receiver operating characteristic (ROC) curve corresponding to IL-8 showed an area under the curve of 0.7 (p = 0.003; 95% CI [0.58–0.81]) and a predictive threshold of 5.27 pg/ml. Positive correlations were found between frailty score, IL-6, and IL-8 levels. In addition, a significant positive correlation was observed between IL-8 levels and Timed Up and Go test results. However, a negative correlation was observed between Mini Nutritional Assessment Short-Form score, IL-6 and CRP levels, as well as between Activities of Daily Living score and serum levels of TNF-α, IL-6, and CRP. In conclusion, the key findings of this study collectively support a role of pro-inflammatory cytokines, TNF-α, CRP, and especially IL-8 in the development of frailty in older adults.


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