Role Of IL-1β Research Articles

Expression and regulation of toll-like receptors (TLRs) in human intervertebral disc cells.

Although inflammatory processes play an essential role in painful intervertebral disc (IVD) degeneration, the underlying regulatory mechanisms are not well understood. This study was designed to investigate the expression, regulation and importance of specific toll-like receptors (TLRs)--which have been shown to play an essential role e.g. in osteoarthritis--during degenerative disc disease. The expression of TLRs in human IVDs was measured in isolated cells as well as in normal or degenerated IVD tissue. The role of IL-1β or TNF-α in regulating TLRs (expression/activation) as well as in regulating activity of down-stream pathways (NF-κB) and expression of inflammation-related genes (IL-6, IL-8, HSP60, HSP70, HMGB1) was analyzed. Expression of TLR1/2/3/4/5/6/9/10 was detected in isolated human IVD cells, with TLR1/2/4/6 being dependent on the degree of IVD degeneration. Stimulation with IL-1β or TNF-α moderately increased TLR1/TLR4 mRNA expression (TNF-α only), and strongly increased TLR2 mRNA expression (IL-1β/TNF-α), with the latter being confirmed on the protein level. Stimulation with IL-1β, TNF-α or Pam3CSK4 (a TLR2-ligand) stimulated IL-6 and IL-8, which was inhibited by a TLR2 neutralizing antibody for Pam3CSK4; IL-1β and TNF-α caused NF-κB activation. HSP60, HSP70 and HMGB1 did not increase IL-6 or IL-8 and were not regulated by IL-1β/TNF-α. We provide evidence that several TLRs are expressed in human IVD cells, with TLR2 possibly playing the most crucial role. As TLRs mediate catabolic and inflammatory processes, increased levels of TLRs may lead to aggravated disc degeneration, chronic inflammation and pain development. Especially with the identification of more endogenous TLR ligands, targeting these receptors may hold therapeutic promise.

Differences in PGE2 production between primary human monocytes and differentiated macrophages: role of IL-1β and TRIF/IRF3.

Prostaglandin E2 (PGE2) is induced in vivo by bacterial products including TLR agonists. To determine whether PGE2 is induced directly or via IL-1β, human monocytes and macrophages were cultured with LPS or with Pam3CSK4 in presence of caspase-1 inhibitor, ZVAD, or IL-1R antagonist, Kineret. TLR agonists induced PGE2 in macrophages exclusively via IL-1β-independent mechanisms. In contrast, ZVAD and Kineret reduced PGE2 production in LPS-treated (but not in Pam3CSK4-treated) monocytes, by 30–60%. Recombinant human IL-1β augmented COX-2 and mPGES-1 mRNA and PGE2 production in LPS-pretreated monocytes but not in un-primed or Pam3CSK4-primed monocytes. This difference was explained by the finding that LPS but not Pam3CSK4 induced phosphorylation of IRF3 in monocytes suggesting activation of the TRIF signaling pathway. Knocking down TRIF, TRAM, or IRF3 genes by siRNA inhibited IL-1β-induced COX-2 and mPGES-1 mRNA. Blocking of TLR4 endocytosis during LPS priming prevented the increase in PGE2 production by exogenous IL-1β. Our data showed that TLR2 agonists induce PGE2 in monocytes independently from IL-1β. In the case of TLR4, IL-1β augments PGE2 production in LPS-primed monocytes (but not in macrophages) through a mechanism that requires TLR4 internalization and activation of the TRIF/IRF3 pathway. These findings suggest a key role for blood monocytes in the rapid onset of fever in animals and humans exposed to bacterial products and some novel adjuvants.

NLRP3 inflammasome activation in Alzheimer's disease (INC9P.446)

Abstract Neuroinflammation is now recognized as a fundamental response in Alzheimer’s pathology. Prominent activation of inflammatory responses has been observed in the brains of patients with Alzheimer’s disease, as well as in mouse models, however the role of neuroinflammation in Alzheimer’s disease pathogenesis is still not clear. We have reported that the fibrillar form of beta amyloid is capable of stimulating the production of the inflammatory cytokine IL-1β from microglia cells through the activation of the NLRP3 inflammasome. NLRP3 mediated IL-1β production, in turn, induced neurotoxic factors from microglia cells and resulted in neuronal cell death. More importantly, we have recently bred the APP/PS1 mouse into the NLRP3 knock out mice and showed that NLRP3 deficient APP/PS1 mice were completely protected from learning and memory deficits and had decreased Amyloid beta plaques. NLRP3 activation induces both IL-1β and IL18 production. However the role of IL-1β or IL-18, both downstream of NLRP3 inflammasomes, in neuronal cell death are not clear. We used microglia cells and mouse neuronal cell line co-culture system to show the increased neuronal cell death was dependent on the activation of caspase-1 when stimulating microglia cells with Amyloid beta. In addition, IL-1β or IL-18 have synergistic effect in inducing neuronal cell death.

IL-1β-stimulated urokinase plasminogen activator expression through NF-κB in gastric cancer after HGF treatment

The potential of hepatocyte growth factor (HGF) to regulate the expression of urokinase plasminogen activator (uPA) in a gastric cancer cell is not widely acknowledged. To identify the genes associated with the plasminogen activator proteolytic axis by HGF, we used cDNA microarray technology and selected genes upregulated or downregulated in two gastric cell lines (NUGC-3 and MKN-28). First, IL-1β RNA and protein were confirmed to be upregulated. Then, we investigated the effect of IL-1β induced by HGF on the uPA system, facilitating the migration and invasion of cancer cells in the metastatic process. The role for IL-1β in HGF-induced upregulation of uPA was determined by knockdown of IL-1β with IL-1β shRNA and a chromatin immune precipitation assay. The levels of IL-1β and uPA were upregulated in cells treated with HGF in a dose-dependent manner. HGF-induced upregulation of uPA was suppressed by IL-1β knockdown. HGF enhanced the binding activity of NF-κB to the uPA promoter in control cells, but not in the IL-1β shRNA cells. We confirmed the functional role of HGF inactivation of the uPA promoter by a reporter gene assay. Downregulation of IL-1β using IL-1β shRNA also decreased cell proliferation and in vitro cell invasion. IL-1β stimulated uPA expression through ERK and NF-κB in gastric cancer, which may therefore be promising targets for gastric cancer therapy.

Interleukin-1β Attenuates Myofibroblast Formation and Extracellular Matrix Production in Dermal and Lung Fibroblasts Exposed to Transforming Growth Factor-β1

One of the most potent pro-fibrotic cytokines is transforming growth factor (TGFβ). TGFβ is involved in the activation of fibroblasts into myofibroblasts, resulting in the hallmark of fibrosis: the pathological accumulation of collagen. Interleukin-1β (IL1β) can influence the severity of fibrosis, however much less is known about the direct effects on fibroblasts. Using lung and dermal fibroblasts, we have investigated the effects of IL1β, TGFβ1, and IL1β in combination with TGFβ1 on myofibroblast formation, collagen synthesis and collagen modification (including prolyl hydroxylase, lysyl hydroxylase and lysyl oxidase), and matrix metalloproteinases (MMPs). We found that IL1β alone has no obvious pro-fibrotic effect on fibroblasts. However, IL1β is able to inhibit the TGFβ1-induced myofibroblast formation as well as collagen synthesis. Glioma-associated oncogene homolog 1 (GLI1), the Hedgehog transcription factor that is involved in the transformation of fibroblasts into myofibroblasts is upregulated by TGFβ1. The addition of IL1β reduced the expression of GLI1 and thereby also indirectly inhibits myofibroblast formation. Other potentially anti-fibrotic effects of IL1β that were observed are the increased levels of MMP1, −2, −9 and −14 produced by fibroblasts exposed to TGFβ1/IL1β in comparison with fibroblasts exposed to TGFβ1 alone. In addition, IL1β decreased the TGFβ1-induced upregulation of lysyl oxidase, an enzyme involved in collagen cross-linking. Furthermore, we found that lung and dermal fibroblasts do not always behave identically towards IL1β. Suppression of COL1A1 by IL1β in the presence of TGFβ1 is more pronounced in lung fibroblasts compared to dermal fibroblasts, whereas a higher upregulation of MMP1 is seen in dermal fibroblasts. The role of IL1β in fibrosis should be reconsidered, and the differences in phenotypical properties of fibroblasts derived from different organs should be taken into account in future anti-fibrotic treatment regimes.

The impact of Interleukin-1β on the structure of human umbilical vein endothelial cells and aquaporin-1 expression

Objective To explore the role of IL-1β in capillary leak syndrome by observing the alterations of AQP-1 expression,apoptosis,and ultrastructural of vascular endothelial cells under the action of IL-1β.Methods Umbilical vein endothelial cells (UVEC) in vitro were randomly allocated into 3 groups:time,concentration,and control.In the time group,UVECs were treated with culture medium containing 20 μg/L IL-1β for3 h(T1),8 h(T2),12 h(T3) and 24 h(T4).In the concentration group,UVECs were treated with culture medium containing 0.2 μg/L(C1),2 μg/L(C2) and 20 μg/L(C3) IL-1β for 24 h.In the control group,UVECs were treated with culture medium without IL-1β for 24 h.The changes of AQP-1 mRNA and protein expression were detected by real-time PCR and Western blot.Apoptosis was detected by flow cytometry,and cell ultrastructural changes were observed by electron microscopy.Results AQP-1 mRNA and protein expression of T1-T4 in the time group and C1-C3 in the concentration group were lower than those of the control group (P ＜ 0.05).The apoptotic rate was increased,and mitochondrial swelling,vacuolar degeneration,karyolysis and necrosis were observed under electron microscopy.These were more pronounced with time or concentration increases.Conclusions IL-1β can cause a decrease of AQP-1 mRNA and protein expression,increase in apoptotic rate and increase in damage to the cells'ultrastructure.This is an important reason for damage to the vascular endothelial barrier and may be associated with capillary leak syndrome. Key words: Capillary leak syndrome; Vascular endothelial barrier; Interleukin-1β ; Aquaporin-1 ; Apoptosis

Rheumatoid arthritis and genetic variations in cytokine genes: a population-based study in Kashmir Valley

Objective: The aim of our study was to determine the genetic associations between polymorphisms of the IL1β gene (−511C/T and +3953C/T) and IL6 gene (−174G/C) with disease susceptibility and severity in patients with rheumatoid arthritis (RA) in ethnic Kashmiri population.Methods: Allele and genotype frequencies of IL1β −511 C/T, IL1β +3953 C/T and IL6 −174 G/C polymorphisms were compared between 150 RA patients and 200 healthy controls by using PCR-RFLP method.Results: We did not find any significant association between IL1b +3953 C/T and IL6 −174 G/C polymorphism and Rheumatoid Arthritis risk (p > 0.05), but IL1β +3953 CT genotype was associated significantly with increased SJC and ESR and IL6 −174 GG genotype was associated significantly with increased ESR. However IL1b −511C/T polymorphism was significantly associated with rheumatoid arthritis risk and the carriers of IL1β −511 ‘C’ allele (CC and TC genotypes) appeared to have lower risk for RA development.Conclusion: Our findings suggest that the IL1b −511 ‘C’ allele has a protective role from disease development. Furthermore our results suggest a possible role of IL1b +3953 CT and IL6 −174 GG genotypes as disease activity markers of rheumatoid arthritis.

Interleukin-1β promotes hypoxia-induced apoptosis of glioblastoma cells by inhibiting hypoxia-inducible factor-1 mediated adrenomedullin production

Glioblastoma is the most common brain tumor in adults. Advanced glioblastomas normally contain hypoxic areas. The primary cellular responses to hypoxia are generally mediated by the transcription factor hypoxia-inducible factor 1 (HIF-1). Interleukin-1β (IL-1β) is a cytokine that is often present in the glioblastoma microenvironment and is known to be a modulator of glioblastoma progression. However, the role of IL-1β in regulating glioblastoma progression is still controversial. In this study, we found that in the human glioblastoma cell lines U87MG and U138MG, IL-1β inhibits the transactivation activity of HIF-1 by promoting the ubiquitin-independent proteasomal degradation of the oxygen-labile α-subunit of HIF-1 and downregulates the expression of the HIF-1 target gene adrenomedullin (AM). Apoptosis and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assays showed that AM protects glioblastoma cells against hypoxia-induced apoptosis in a dose-dependent manner. Thus, in the presence of IL-1β more glioblastoma cells undergo hypoxia-induced cell death. Our findings suggest that when estimating the influence of IL-1β on the prognosis of glioblastoma patients, factors such as the degree of hypoxia, the expression levels of HIF-1 and AM should be taken into consideration. For the AM-producing glioblastoma cells, IL-1β represents a potent apoptosis inducer.

Role of Interleukin-1β in Radiation-Enhancement of MDA-MB-231 Breast Cancer Cell Invasion

The ability of radiation to increase the invasiveness of cancer cells is associated with the inflammatory response, which is induced in almost all irradiated patients. For breast cancer patients, elevated plasma levels of the inflammatory cytokine interleukin-1β (IL1β) persisted for a few weeks after completion of radiotherapy. The aim of this study was to determine whether IL1β is involved in the enhancement of breast cancer cell invasion induced by radiation. The role of IL1β was assessed with invasion chambers where irradiated fibroblasts were used as chemoattractant for the MDA-MB-231 breast cancer cells plated in the upper compartment. The ability of IL1β to stimulate the expression of cyclooxygenase-2 (COX-2) and biosynthesis of the prostaglandin E2 (PGE2) in MDA-MB-231 cells were also determined. Our results show that radiation-enhancement of MDA-MB-231 cell invasion was prevented with an anti-IL1β antibody. The production of IL1β was increased in irradiated fibroblasts, while the invasiveness of the MDA-MB-231 cells not exposed to irradiated fibroblasts was favored by adding this cytokine. Furthermore, addition of the COX-2 inhibitor NS-398 prevented the stimulation of cancer cell invasion induced either by irradiated fibroblasts or IL1β. We propose that the effect of IL1β on the invasiveness of the MDA-MB-231 cells involves elevation of matrix metalloproteinase-9 (MMP-9) production, induction of COX-2 expression and PGE2 biosynthesis. In conclusion, this study supports the involvement of IL1β in the radiation-enhancement of breast cancer cell invasion.

How should we approach classification of autoinflammatory diseases?

The notion of 'autoinflammatory' disease was introduced at the end of the 1990s, and, since then, this concept has rapidly evolved. As a result, multiple definitions of autoinflammatory disease, and classifications of conditions encompassed by these definitions, have been proposed; this succession highlights advances that have been made in understanding of the innate immune system, and especially the roles of IL-1β and the inflammasome in autoinflammtory conditions. However, the definitions and classifications that have been suggested to date face a number of structure and content issues. We therefore propose another, more clinically-oriented, definition: autoinflammatory diseases are diseases with clinical signs of inflammation, associated with elevated levels of acute-phase reactants, which are attributable to dysfunction of the innate immune system, genetically-determined or triggered by an endogenous factor. From this foundation, we propose a clinically-based classification of autoinflammatory diseases, and go on to discuss how immunological diseases as a whole, including autoimmune diseases, can be appropriately located within a continuum only if the classification process is multidimensional. For this purpose, we appeal to the philosophical concepts of family resemblance and signature.

Neutralization of interleukin-1 beta attenuates silica-induced lung inflammation and fibrosis in C57BL/6 mice

The inflammation and fibrosis induced by silica dust are considered to be substantial responses in silicosis progression. Interleukin-1 beta (IL-1β) plays an important role in silica-induced lung inflammation, but the mechanisms that underlie the influence of IL-1β on the progression of silicosis remain unclear. In this study, the role of IL-1β in silica-induced inflammation and fibrosis was evaluated by administering a suspension of 2.5-mg silica dust, either with or without 40 μg anti-mouse IL-1β monoclonal antibody (mAb), to the lungs of male C57BL/6 mice. Silica + anti-IL-1β mAb-treated mice showed the depletion of IL-1β as well as the attenuation of inflammation, as evaluated in the bronchoalveolar lavage fluid (BALF) and histological sections from 1 to 84 days after silica exposure. Further study of the BALF indicated that inhibition of IL-1β could reduce the contents of tumor necrosis factor-alpha and monocyte chemoattractant protein-1. The real-time PCR and pathology results showed that the neutralization of IL-1β attenuated silica-induced fibrosis by inhibiting the gene expression of transforming growth factor-beta 1, collagen I and fibronectin. The examination of Th1-cytokine and Th2-cytokine suggested that depletion of IL-1β decelerated the Th1/Th2 balance toward a Th2-dominant response. In conclusion, the present study suggests that the neutralization of IL-1β attenuates silica-induced inflammation and fibrosis by inhibiting other inflammatory and fibrogenic mediators and modulating the Th1/Th2 balance.

The Role of IL-1β in the Early Tumor Cell–Induced Angiogenic Response

In this study, we assessed the involvement of IL-1β in early angiogenic responses induced by malignant cells using Matrigel plugs supplemented with B16 melanoma cells. We found that during the angiogenic response, IL-1β and vascular endothelial growth factor (VEGF) interact in a newly described autoinduction circuit, in which each of these cytokines induces the other. The IL-1β and VEGF circuit acts through interactions between bone marrow-derived VEGF receptor 1(+)/IL-1R1(+) immature myeloid cells and tissue endothelial cells. Myeloid cells produce IL-1β and additional proinflammatory cytokines, which subsequently activate endothelial cells to produce VEGF and other proangiogenic factors and provide the inflammatory microenvironment for angiogenesis and tumor progression. These mechanisms were also observed in a nontumor early angiogenic response elicited in Matrigel plugs by either rIL-1β or recombinant VEGF. We have shown that IL-1β inhibition stably reduces tumor growth by limiting inflammation and inducing the maturation of immature myeloid cells into M1 macrophages. In sharp contrast, only transient inhibition of tumor growth was observed after VEGF neutralization, followed by tumor recurrence mediated by rebound angiogenesis. This occurs via the reprogramming of VEGF receptor 1(+)/IL-1R1(+) cells to express hypoxia inducible factor-1α, VEGF, and other angiogenic factors, thereby directly supporting proliferation of endothelial cells and blood vessel formation in a paracrine manner. We suggest using IL-1β inhibition as an effective antitumor therapy and are currently optimizing the conditions for its application in the clinic.

Highway Proximity Associations with Blood Markers of Inflammation: Evidence for a Role for IL-1β

Cardiovascular disease is known to be associated with proximity to major roadways and highways. Thus, blood samples from 20 near highway and 20 urban background residents were analyzed for presence of cytokines and other biomarkers. Near-highway participants displayed significantly lower socioeconomic status (SES) and significantly higher occupational vehicle exhaust exposure and higher low-density lipoprotein (LDL) levels. Controlling for exposure to vehicle exhaust on the job, interleukin-6 (IL-6) was numerically higher in near highway participants. Using logistic regression analyses, IL-1β was significantly elevated near highway. It is interesting that elevations were found in IL-1β, a key cytokine linked to inflammation from particulate matter (PM). More studies are needed with larger sample sizes to assess the possible role of IL-1β.

Interleukin-1 β gene polymorphisms in Egyptian patients with rheumatoid arthritis

The present study aimed at evaluating the role of IL-1β −511 promoter and IL-1β +3953 exon 5 gene polymorphisms in the risk of developing rheumatoid arthritis (RA) and its correlation to disease activity in Egyptian patients. Thirty-two patients having RA as defined by American College of Rheumatology and 20 healthy control subjects were included. All were subjected to DNA analysis for IL-1β −511and IL-1β +3953 gene polymorphisms using PCR-RFLP technique with restriction enzymes AvaI and TaqI, respectively. No special pattern of association could be detected either between IL-1β −511 and +3953 gene polymorphisms and disease susceptibility or between the polymorphisms and the disease activity parameters represented by disease activity score 28 (DAS 28), ESR, and number of swollen and tender joints. Allele distribution failed as well to detect any association with either disease susceptibility or activity; however, a trend towards positive association involving IL-1β −511 C allele was observed (P = 0.054). Our results suggest that IL-1β −511 and IL-1β +3953 gene polymorphisms do not influence the susceptibility to acquire RA in our population with no relation to disease activity. The complex role of the genetic factors in RA and the magnitude of the effects will require further thorough confirmations in other populations and on larger samples to acknowledge this issue.

Cytokine Gene Polymorphisms and Severe Acute Graft-Versus-Host Disease (grade ≥II) After Allogeneic Hematopoietic Stem Cell Transplantation From HLA Identical Siblings

AbstractAbstract 4180Graft-versus-host disease (GvHD) is one of the most important complications after allogeneic hematopoietic stem cell transplantation (HSCT) and influences morbidity and mortality, even when the donor is a human leucocyte antigen (HLA)-matched sibling. Polymorphisms at genes coding for several proinflammatorycytokines and for their related receptors or receptor inhibitors are involved in this complication.To assess the role of cytokine gene polymorphisms on acute GvHD (aGVHD), we analysed 189 pairs of donor and recipients transplanted from HLA identical sibling for malignant hematological diseases between 2000 and 2007, using a non T depleted graft after a myeloablativeor a reduced intensity conditioning regimen. Material and methods:The median age of the recipients at transplantation was 43.4 years (1–68). Two third of the patients received bone marrow before myelo-ablative conditioning regimen and the median delay between diagnosis and transplantation was 9 months (1–76).Five different polymorphisms from 3 cytokine genes were analyzed: IL-10 –592C/A, -819C/T and -1082G/A, IL-1b -511A/G and TGFb1 –509C/T.All the pairs were studied for each gene polymorphism using the Taqman technology as previously described (Malkki2007). Each kit contains several primers pairs for amplification and two allele-specific probes, each of them conjugated with a different fluorescent marker. After amplification, analysis was driven on a Roche LC480 platform. The interpretation of the final results was performed using allelic discrimination specific software.In our study, the frequencies of the TGFb1, IL1b, and IL-10 genotypes in recipients and donors were almost equal, and were consistent with previously reported results for the Caucasoid population and with the NCBI SNP databases. Results:Univariate analysis found a significant negative impact of donor genotypes carrying IL1b A allele (p=0,02) or IL10–592 A allele (p=0,03) on aGvHD.We did not find any effect associated with IL10–819 and -1082 polymorphisms, but as previously described (Lin 2003), the presence of IL10 A-T-A haplotype in the donor, significantly increased the risk of aGVHD (p=0.043). We performed a multivariate analysis on aGVHD incidence taking into account TGFb1–509, IL-10–592 and IL1bpolymorphisms, together with other known risk factors.A higher incidence of aGVHD was found in pairs where donor has an IL1b A allele (HR 4,16 - p=0,0031) and increased when the donor is A/A (HR>15 – p=0,0091). For IL10–592, the impact of the A allele was found different when carried by the donor (higher risk of aGVHD, HR 3,52 – p=0,00083) or the recipient (lower risk of aGVHD, HR 0,48 – p=0,024), but this effect seems only significant in pairs where donor did not carry any A allele (rec AC × don CC – HR 0.2 – p=0.05). Donor with TGFb1–509 T allele was found to have a significant lower risk of aGVHD (HR 0,42 – p=0,02). (table 1).The role of the cytokine cascade in the physiopathology of GVHD is well established. Our study documents the possible role of IL-1b, TGFb1and IL10 gene polymorphisms in this setting.A proven association of cytokine gene polymorphisms with acute GVHD would enable the clinician to modify the therapeutic strategy and enhance the outcomes.Table 1CytokineAllele recHRpAllele donHRpRecx donReferenceHRpIL1bA2.130.036AG × AGGG × GG4.160.0031GG × AGGG × GG4.350.028AA × AAGG × GG>150.0091TGFbT0.420.02CC × CTCC × CC0.250.012CT × CTCC × CC0.140.0013IL10-592A0.480.024A3.520.00083AC × ACCC × CC2.460.038CC × ACCC × CC4.930.013ACx CCCC × CC0.20.05 Disclosures:Nicolini:Novartis, Bristol Myers-Squibb, Pfizer, ARIAD, and Teva: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Cytokines Induced Neutrophil Extracellular Traps Formation: Implication for the Inflammatory Disease Condition

Neutrophils (PMNs) and cytokines have a critical role to play in host defense and systemic inflammatory response syndrome (SIRS). Neutrophil extracellular traps (NETs) have been shown to extracellularly kill pathogens, and inflammatory potential of NETs has been shown. Microbial killing inside the phagosomes or by NETs is mediated by reactive oxygen and nitrogen species (ROS/RNS). The present study was undertaken to assess circulating NETs contents and frequency of NETs generation by isolated PMNs from SIRS patients. These patients displayed significant augmentation in the circulating myeloperoxidase (MPO) activity and DNA content, while PMA stimulated PMNs from these patients, generated more free radicals and NETs. Plasma obtained from SIRS patients, if added to the PMNs isolated from healthy subjects, enhanced NETs release and free radical formation. Expressions of inflammatory cytokines (IL-1β, TNFα and IL-8) in the PMNs as well as their circulating levels were significantly augmented in SIRS subjects. Treatment of neutrophils from healthy subjects with TNFα, IL-1β, or IL-8 enhanced free radicals generation and NETs formation, which was mediated through the activation of NADPH oxidase and MPO. Pre-incubation of plasma from SIRS with TNFα, IL-1β, or IL-8 antibodies reduced the NETs release. Role of IL-1β, TNFα and IL-8 thus seems to be involved in the enhanced release of NETs in SIRS subjects.

Contractile, but not endothelial, dysfunction in early inflammatory arthritis: a possible role for matrix metalloproteinase‐9

BACKGROUND AND PURPOSEExcess morbidity/mortality in rheumatoid arthritis (RA) is associated with increased incidence of cardiovascular disease. In this ‘proof-of-concept’ study, vascular function was characterized in the murine collagen-induced arthritis (mCIA) model, the benchmark choice for evaluation of the pathological processes and assessment of new therapies.EXPERIMENTAL APPROACHMice in the very early stages of arthritis development [and appropriate naïve (non-immunized) age-matched controls] were used in the study. Blood pressure was measured using tail cuff plethysmography. Vascular function in rings of isolated aorta was studied with isometric tension myography. Levels of NO metabolites (NOx), MMP-9 protein and IL-1β in plasma and MMP-9 protein in aortic homogenates were quantified.KEY RESULTSImpaired vascular contractile responses in arthritis were unaffected by ex vivo inhibition of NOS (endothelial/neuronal and inducible) or COX activities. Endothelium-dependent and -independent relaxation, plasma NOx and blood pressure were unaffected by arthritis. Plasma and aortic homogenate MMP-9 protein levels were increased significantly in arthritis. Incubation of aortic tissues from naïve control animals with exogenous MMP-9 impaired subsequent contractile responses, mirroring that observed in arthritis. A role for IL-1β in perpetuating contractile dysfunction and increasing aortic MMP-9 was excluded.CONCLUSIONS AND IMPLICATIONSThese data identify for the first time a relationship between early arthritis and contractile dysfunction and a possible role for MMP-9 therein, in the absence of overt endothelial dysfunction or increased NO production. As such, MMP-9 may constitute a significant target for early intervention in RA patients with a view to decreasing risk of cardiovascular disease.

IL-1β enhances cell adhesion to degraded fibronectin.

IL-1β is a prominent proinflammatory cytokine that mediates degradation of extracellular matrix proteins through increased expression of matrix metalloproteinases, which involves a signaling pathway in adherent cells that is restricted by focal adhesions. Currently, the mechanism by which IL-1β affects cell adhesion to matrix proteins is not defined, and it is not known whether degraded matrix proteins affect IL-1β signaling. We examined adhesion-related IL-1β signaling in fibroblasts attaching to native or MMP3-degraded fibronectin. IL-1β increased cell attachment, resistance to shear force and the numbers of focal adhesions containing activated β(1) integrins. IL-1β-enhanced attachment required FAK, kindlins 1/2, and talin. MMP3-degraded fibronectin-inhibited IL-1β-enhanced cell adhesion and promoted spontaneous ERK activation that was independent of IL-1β treatment. We conclude that IL-1β enhances the adhesion of anchorage-dependent cells to MMP3-degraded fibronectin, which, in turn, is associated with deregulated cellular responses to IL-1β. These data point to a novel role of IL-1β as a proadhesive signaling molecule in inflammation that employs kindlins and talin to regulate adhesion.

Rapid Vascular Responses to Anthrax Lethal Toxin in Mice Containing a Segment of Chromosome 11 from the CAST/Ei Strain on a C57BL/6 Genetic Background

Host allelic variation controls the response to B. anthracis and the disease course of anthrax. Mouse strains with macrophages that are responsive to anthrax lethal toxin (LT) show resistance to infection while mouse strains with LT non-responsive macrophages succumb more readily. B6.CAST.11M mice have a region of chromosome 11 from the CAST/Ei strain (a LT responsive strain) introgressed onto a LT non-responsive C57BL/6J genetic background. Previously, B6.CAST.11M mice were found to exhibit a rapid inflammatory reaction to LT termed the early response phenotype (ERP), and displayed greater resistance to B. anthracis infection compared to C57BL/6J mice. Several ERP features (e.g., bloat, hypothermia, labored breathing, dilated pinnae vessels) suggested vascular involvement. To test this, Evan’s blue was used to assess vessel leakage and intravital microscopy was used to monitor microvascular blood flow. Increased vascular leakage was observed in lungs of B6.CAST.11M mice compared to C57BL/6J mice 1 hour after systemic administration of LT. Capillary blood flow was reduced in the small intestine mesentery without concomitant leukocyte emigration following systemic or topical application of LT, the latter suggesting a localized tissue mechanism in this response. Since LT activates the Nlrp1b inflammasome in B6.CAST.11M mice, the roles of inflammasome products, IL-1β and IL-18, were examined. Topical application to the mesentery of IL-1β but not IL-18 revealed pronounced slowing of blood flow in B6.CAST.11M mice that was not present in C57BL/6J mice. A neutralizing anti-IL-1β antibody suppressed the slowing of blood flow induced by LT, indicating a role for IL-1β in the response. Besides allelic differences controlling Nlrp1b inflammasome activation by LT observed previously, evidence presented here suggests that an additional genetic determinant(s) could regulate the vascular response to IL-1β. These results demonstrate that vessel leakage and alterations to blood flow are part of the rapid response in mice resistant to B. anthracis infection.

The role of interleukin-1β in human trophoblast motility

The pleiotropic cytokine interleukin-1β (IL-1β) can promote physiological cell migration, as well as cancer cell invasion and metastasis. Its role in human trophoblast invasion, however, has not been satisfactorily answered since direct, indirect as well as no effects on trophoblast motility have been published. Therefore, the role of IL-1β has been re-evaluated by exclusively using human primary trophoblast model systems. Immunofluorescence of first trimester placentae indicated IL-1 receptor 1 (IL-1R1) protein expression in first trimester villous cytotrophoblasts (vCTB) and extravillous trophoblasts (EVT). The latter expressed higher mRNA levels of the receptor as shown by comparative gene chip data of vCTB and EVT. Similarly, Western blot analyses and immunofluorescence revealed a time- and differentiation-dependent increase of IL-1R1 in primary EVT seeded on fibronectin. IL-1β dose-dependently elevated migration of isolated first trimester EVT through fibronectin-coated transwells, which was inhibited in the presence of IL-1R antagonist (IL-1Ra), whereas proliferation of these cells was not affected. Similarly, the interleukin did not alter proliferation of vCTB and cell column trophoblasts in floating villi of early pregnancy, but promoted migration in villous explant cultures seeded on collagen I. Western blot analyses of supernatants of primary EVT and first trimester villous explant cultures revealed IL-1β induced secretion of urokinase plasminogen activator (uPA), plasminogen activator inhibitor (PAI)-1 and PAI-2, which was diminished upon combined IL-1β/IL-1Ra treatment. In conclusion, these data suggest that IL-1β directly promotes trophoblast motility of first trimester EVT involving the uPA/PAI system.