Differential regulation of proinflammatory mediators following LPS- and ATP-induced activation of monocytes from patients with antiphospholipid syndrome.
15 Feb 2015-BioMed Research International (Hindawi Publishing Corporation)-Vol. 2015, pp 292851-292851
TL;DR: Increased sensitivity of APS cells to LPS that may contribute to thrombus formation and enhance development or progression of autoimmune processes is indicated.
Abstract: Antiphospholipid syndrome (APS) is an acquired autoimmune disorder characterized by recurrent thrombosis and pregnancy morbidity in association with the presence of antiphospholipid antibodies. Growing evidence supports the involvement of monocytes in APS pathogenesis. Inflammatory activation of monocytes promotes thrombus formation and other APS complications. However, mechanisms underlying their activation are poorly investigated. We aimed to determine transcriptional activity of monocytes after exposing them to low concentrations of lipopolysaccharide (LPS) and LPS + adenosine triphosphate (ATP) using comparative qRT-PCR. The results showed that LPS significantly increased transcriptional levels of TLR2, IL-23, CCL2, CXCL10, IL-1β, and IL-6 in APS cells, while, in cells from healthy donors, LPS resulted in IL-6 and STAT3 elevated mRNAs. Double stimulation of the cells resulted in decreased mRNA levels of NLRP3 in monocytes isolated from healthy donors and CCL2, IL-1β in APS cells. By contrast, TLR2 mRNAs were elevated in both investigated groups after culture of the cells with LPS + ATP. Thus, the findings indicate increased sensitivity of APS cells to LPS that may contribute to thrombus formation and enhance development or progression of autoimmune processes. Low concentrations of ATP diminish LPS-induced inflammatory state of APS monocytes which might be a potential mechanism which regulates inflammatory state of the cells.
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TL;DR: A plea is made for future extensive immune cell profiling by a systems medicine approach in order to better unravel the pathogenesis of APS to gain more insight in the role of the immune system in APS as well as having the potential to reveal biomarkers or novel therapeutic targets.
Abstract: The antiphospholipid syndrome (APS) is a systemic autoimmune disease that is characterized serologically by the presence of antiphospholipid antibodies (aPL) and clinically by vascular thrombosis and obstetric complications. The protein β2 glycoprotein I (β2GPI) is identified as the most important autoantigen in this syndrome. Activation of endothelial cells, thrombocytes and placental tissue by anti-β2GPI antibodies relates to the clinical manifestations of APS. This review describes genetic and environmental factors in relation to APS and summarizes the current knowledge on abnormalities in components of both the innate and adaptive immune system in APS. The role of dendritic cells, T-cells, B-cells, monocytes, neutrophils and NK-cells as well as the complement system in APS are discussed. Several gaps in our knowledge on the pathophysiology of APS are identified and a plea is made for future extensive immune cell profiling by a systems medicine approach in order to better unravel the pathogenesis of APS, to gain more insight in the role of the immune system in APS as well as having the potential to reveal biomarkers or novel therapeutic targets.
53 citations
TL;DR: This review summarizes and critically assess the pathogenic and non-pathogenic formation of aPLs and its contribution to the development of APS.
Abstract: Antiphospholipid antibodies (aPLs) comprise a diverse family of autoantibodies targeted against proteins with the affinity toward negatively charged phospholipids or protein-phospholipid complexes. Their clinical significance, including prothrombotic potential of anti-cardiolipin antibodies (aCLs), anti-β2-glycoprotein I antibodies (aβ2-GPIs), and lupus anti-coagulant (LA), is well-established. However, the ontogeny of these pathogenic aPLs remains less clear. While transient appearance of aPLs could be induced by various environmental factors, in genetically predisposed individuals these factors may eventually lead to the development of the antiphospholipid syndrome (APS). Since the first description of APS, it has been found that a wide variety of microbial and viral agents influence aPLs production and contribute to clinical manifestations of APS. Many theories attempted to explain the pathogenic potential of different environmental factors as well as a phenomenon termed molecular mimicry between β2-GPI molecule and infection-relevant structures. In this review, we summarize and critically assess the pathogenic and non-pathogenic formation of aPLs and its contribution to the development of APS.
38 citations
Cites background from "Differential regulation of proinfla..."
...It is a widely accepted view that pathogenesis of many autoimmune diseases is largely driven by inappropriate or inadequate immune responses toward bacterial agents (50, 51)....
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TL;DR: LDL(−) promotes release of biologically active IL-1β in monocytes and MDM by induction of the two steps involved: priming and NLRP3 inflammasome activation.
Abstract: Background: Electronegative LDL (LDL(−)), a modified LDL fraction found in blood, induces the release of inflammatory mediators in endothelial cells and leukocytes However, the inflammatory pathways activated by LDL(−) have not been fully defined We aim to study whether LDL(−) induced release of the first-wave proinflammatory IL-1β in monocytes and monocyte-derived macrophages (MDM) and the mechanisms involved Methods: LDL(−) was isolated from total LDL by anion exchange chromatography Monocytes and MDM were isolated from healthy donors and stimulated with LDL(+) and LDL(−) (100 mg apoB/L) Results: In monocytes, LDL(−) promoted IL-1β release in a time-dependent manner, obtaining at 20 h-incubation the double of IL-1β release induced by LDL(−) than by native LDL LDL(−)-induced IL-1β release involved activation of the CD14-TLR4 receptor complex LDL(−) induced priming, the first step of IL-1β release, since it increased the transcription of pro-IL-1β (8-fold) and NLRP3 (3-fold) compared to native LDL Several findings show that LDL(−) induced inflammasome activation, the second step necessary for IL-1β release Preincubation of monocytes with K+ channel inhibitors decreased LDL(−)-induced IL-1β release LDL(−) induced formation of the NLRP3-ASC complex LDL(−) triggered 2-fold caspase-1 activation compared to native LDL and IL-1β release was strongly diminished in the presence of the caspase-1 inhibitor Z-YVAD In MDM, LDL(−) promoted IL-1β release, which was also associated with caspase-1 activation Conclusions: LDL(−) promotes release of biologically active IL-1β in monocytes and MDM by induction of the two steps involved: priming and NLRP3 inflammasome activation Significance: By IL-1β release, LDL(−) could regulate inflammation in atherosclerosis
37 citations
TL;DR: The results suggest that arterial hypertension and monocyte counts may be independent factors for thrombosis recurrence in APS, and may support the evaluation of therapeutic measures to a rigid control of blood pressures and modulation of inflammatory response in APs, as additional prophylaxis against the recurrence of vascular events.
Abstract: Introduction Antiphospholipid syndrome (APS) is a pro-thrombotic autoimmune disease that affects different vascular beds, with potential risk for recurrence. Systemic lupus erythematosus (SLE), specific autoantibodies profile and atherogenic disorders have been described as risk factors for the occurrence of first thrombosis in patients with antiphospholipid antibodies (aPL). However, factors associated with recurrent thrombosis have not yet been completely elucidated in APS. The aim of this study was to evaluate the association of recurrent thrombosis with markers of inflammation, autoimmunity and the presence of atherogenic disorders in APS patients. Materials and methods We performed a retrospective evaluation of a cohort of APS patients in order to determine if markers of inflammation, autoimmunity and cardiovascular risk were associated with recurrence of thrombosis. Results One hundred fifteen patients with APS were included, 60% had primary APS. History of recurrent thrombosis was positive in 38.3% of patients, and 40% of them were on oral anticoagulants at the time of recurrence. Independent risk factors associated with recurrent thrombosis were arterial hypertension (OR = 3.7, 95% CI = 1.6–8.5, P = 0.002) and monocytosis above 500 u/mm 3 (OR = 2.4, 95% CI = 1.2–5.3, P = 0.02). These factors were particularly relevant in cases of venous index event. Conclusion The results suggest that arterial hypertension and monocyte counts may be independent factors for thrombosis recurrence in APS. Given the morbidity of recurrent cases, the results may support the evaluation of therapeutic measures to a rigid control of blood pressures and modulation of inflammatory response in APS, as additional prophylaxis against the recurrence of vascular events.
25 citations
Cites background from "Differential regulation of proinfla..."
...Monocytes have been recognized as key cells for the pathogenesis of APS [11] and previous “in vitro” and clinical studies have demonstrated an increased activation of monocytes in patients with APS [27,28]....
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...For the pathogenesis of thrombotic APS, the immune-complex formed by aCL or aβ2GP1 and their antigens, in particular LDL oxidized, would activatemonocytes to express tissue factor, to secrete inflammatory cytokines [11,27] and possibly contribute to the formation of atherosclerotic plaques on the vascular wall [30]....
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TL;DR: Levels of sTREM-1 might serve as a biomarker for thrombosis in patients with primary antiphospholipid syndrome as well as other predictors (thrombotic PAPS-ever, age, and sex).
Abstract: Soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) is an innate-immune receptor found in blood. Its presence reflects innate immune cell activation. We sought to investigate plasma sTREM-1 levels in patients with primary antiphospholipid syndrome (PAPS). A cross-sectional, case-control design was used. Plasma sTREM-1 levels were analyzed by enzyme-linked immunosorbent assay (ELISA) in consecutive patients diagnosed with PAPS or asymptomatic antiphospholipid antibody (APLA) carriers and controls. The study cohort included 33 patients with PAPS, 10 asymptomatic APLA carriers, and 73 controls. Mean plasma sTREM-1 levels were significantly higher in patients with PAPS (299.2 ± 146.7 pg/ml) and thrombotic PAPS-ever (current and past thrombotic event) (327.2 ± 151.3 pg/ml) compared with controls (230.2 ± 85.5 pg/ml; p = 0.006 and p = 0.003, respectively), patients with thrombotic PAPS compared with patients with past obstetric APS (195.12 ± 58.52 pg/ml, p = 0.01) and APLA carriers (215.8 ± 51.6 pg/ml, p = 0.02), patients with current thrombotic PAPS (429.5 ± 227.5 pg/ml) compared with patients with past thrombotic PAPS (289.5 ± 94.65 pg/ml, p = 0.01), and patients with PAPS who had ever had a stroke or venous thromboembolic event compared with patients who had not (p = 0.007 and p = 0.02, respectively). On receiver operator characteristic curve analysis, plasma sTREM-1 levels differentiated patients with current thrombotic PAPS from asymptomatic APLA carriers and controls, with an area under the curve of 0.7292 (p = 0.0014) and 0.88 (p < 0.0001), respectively. Multivariate regression analysis to identify sTREM-1 predictors (thrombotic PAPS-ever, age, and sex) yielded an independent association of sTREM-1 levels with thrombotic PAPS (p < 0.0001). Plasma sTREM-1 levels are significantly elevated in patients with thrombotic PAPS. Levels of sTREM-1 might serve as a biomarker for thrombosis in patients with PAPS.
10 citations
References
More filters
TL;DR: Microbial recognition by Toll-like receptors helps to direct adaptive immune responses to antigens derived from microbial pathogens to distinguish infectious nonself from noninfectious self.
Abstract: ▪ Abstract The innate immune system is a universal and ancient form of host defense against infection. Innate immune recognition relies on a limited number of germline-encoded receptors. These receptors evolved to recognize conserved products of microbial metabolism produced by microbial pathogens, but not by the host. Recognition of these molecular structures allows the immune system to distinguish infectious nonself from noninfectious self. Toll-like receptors play a major role in pathogen recognition and initiation of inflammatory and immune responses. Stimulation of Toll-like receptors by microbial products leads to the activation of signaling pathways that result in the induction of antimicrobial genes and inflammatory cytokines. In addition, stimulation of Toll-like receptors triggers dendritic cell maturation and results in the induction of costimulatory molecules and increased antigen-presenting capacity. Thus, microbial recognition by Toll-like receptors helps to direct adaptive immune responses ...
8,041 citations
"Differential regulation of proinfla..." refers background in this paper
...Toll-like receptors (TLRs) are membrane receptors responsible for the self- and nonself-recognition of evolutionarily conserved structures on pathogens, termed pathogen-associated molecular patterns (PAMPs) such as lipopolysaccharide (LPS) [16, 17]....
[...]
TL;DR: The role of PRRs, their signaling pathways, and how they control inflammatory responses are discussed.
Abstract: Infection of cells by microorganisms activates the inflammatory response. The initial sensing of infection is mediated by innate pattern recognition receptors (PRRs), which include Toll-like receptors, RIG-I-like receptors, NOD-like receptors, and C-type lectin receptors. The intracellular signaling cascades triggered by these PRRs lead to transcriptional expression of inflammatory mediators that coordinate the elimination of pathogens and infected cells. However, aberrant activation of this system leads to immunodeficiency, septic shock, or induction of autoimmunity. In this Review, we discuss the role of PRRs, their signaling pathways, and how they control inflammatory responses.
6,987 citations
"Differential regulation of proinfla..." refers background in this paper
...Toll-like receptors (TLRs) are membrane receptors responsible for the self- and nonself-recognition of evolutionarily conserved structures on pathogens, termed pathogen-associated molecular patterns (PAMPs) such as lipopolysaccharide (LPS) [16, 17]....
[...]
TL;DR: The investigation of the differentiation, effector function, and regulation of Th17 cells has opened up a new framework for understanding T cell differentiation and now appreciate the importance of Th 17 cells in clearing pathogens during host defense reactions and in inducing tissue inflammation in autoimmune disease.
Abstract: CD4+ T cells, upon activation and expansion, develop into different T helper cell subsets with different cytokine profiles and distinct effector functions. Until recently, T cells were divided into Th1 or Th2 cells, depending on the cytokines they produce. A third subset of IL-17-producing effector T helper cells, called Th17 cells, has now been discovered and characterized. Here, we summarize the current information on the differentiation and effector functions of the Th17 lineage. Th17 cells produce IL-17, IL-17F, and IL-22, thereby inducing a massive tissue reaction owing to the broad distribution of the IL-17 and IL-22 receptors. Th17 cells also secrete IL-21 to communicate with the cells of the immune system. The differentiation factors (TGF-β plus IL-6 or IL-21), the growth and stabilization factor (IL-23), and the transcription factors (STAT3, RORγt, and RORα) involved in the development of Th17 cells have just been identified. The participation of TGF-β in the differentiation of Th17 cells places ...
4,548 citations
TL;DR: It is shown that cryopyrin-deficient macrophages cannot activate caspase-1 in response to Toll-like receptor agonists plus ATP, the latter activating the P2X7 receptor to decrease intracellular K+ levels.
Abstract: A crucial part of the innate immune response is the assembly of the inflammasome, a cytosolic complex of proteins that activates caspase-1 to process the proinflammatory cytokines interleukin (IL)-1beta and IL-18. The adaptor protein ASC is essential for inflammasome function, binding directly to caspase-1 (refs 3, 4), but the triggers of this interaction are less clear. ASC also interacts with the adaptor cryopyrin (also known as NALP3 or CIAS1). Activating mutations in cryopyrin are associated with familial cold autoinflammatory syndrome, Muckle-Wells syndrome and neonatal onset multisystem inflammatory disease, diseases that are characterized by excessive production of IL-1beta. Here we show that cryopyrin-deficient macrophages cannot activate caspase-1 in response to Toll-like receptor agonists plus ATP, the latter activating the P2X7 receptor to decrease intracellular K+ levels. The release of IL-1beta in response to nigericin, a potassium ionophore, and maitotoxin, a potent marine toxin, was also found to be dependent on cryopyrin. In contrast to Asc-/- macrophages, cells deficient in the gene encoding cryopyrin (Cias1-/-) activated caspase-1 and secreted normal levels of IL-1beta and IL-18 when infected with Gram-negative Salmonella typhimurium or Francisella tularensis. Macrophages exposed to Gram-positive Staphylococcus aureus or Listeria monocytogenes, however, required both ASC and cryopyrin to activate caspase-1 and secrete IL-1beta. Therefore, cryopyrin is essential for inflammasome activation in response to signalling pathways triggered specifically by ATP, nigericin, maitotoxin, S. aureus or L. monocytogenes.
2,789 citations
"Differential regulation of proinfla..." refers background in this paper
...In recent years, it has been recognized that extracellular ATP, released from intracellular stores in response to cellular stress or inflammation, may function as a “danger” signal which modulates response of the innate immune system [40, 41]....
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TL;DR: The role of NLRs, and in particular the inflammasomes, in the recognition of microbial and danger components and the role they play in health and disease are discussed.
Abstract: The innate immune system relies on its capacity to rapidly detect invading pathogenic microbes as foreign and to eliminate them. The discovery of Toll-like receptors (TLRs) provided a class of membrane receptors that sense extracellular microbes and trigger antipathogen signaling cascades. More recently, intracellular microbial sensors have been identified, including NOD-like receptors (NLRs). Some of the NLRs also sense nonmicrobial danger signals and form large cytoplasmic complexes called inflammasomes that link the sensing of microbial products and metabolic stress to the proteolytic activation of the proinflammatory cytokines IL-1β and IL-18. The NALP3 inflammasome has been associated with several autoinflammatory conditions including gout. Likewise, the NALP3 inflammasome is a crucial element in the adjuvant effect of aluminum and can direct a humoral adaptive immune response. In this review, we discuss the role of NLRs, and in particular the inflammasomes, in the recognition of microbial and danger components and the role they play in health and disease.
2,217 citations
"Differential regulation of proinfla..." refers background in this paper
...The most studied one is the NLRP3 (NOD-like receptor family, pyrin domain containing 3) inflammasome which may be triggered by diverse stimuli, including PAMPs, toxins, or damage-associated molecular patterns (DAMPs) [23]....
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