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Perioperative Dynamics of TLR2, TLR4, and TREM-1 Expression in Monocyte Subpopulations in the Setting of On-Pump Coronary Artery Bypass Surgery. ISRN INFLAMMATION 2013; 2013:817901. [PMID: 24049665 PMCID: PMC3767242 DOI: 10.1155/2013/817901] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 02/19/2013] [Indexed: 01/04/2023]
Abstract
Hypercytokinemia plays a key role in the pathogenesis of systemic inflammatory response syndrome (SIRS). Monocytes are the main source of cytokines in the early inflammatory phase. Simultaneous stimulation of toll-like receptors (TLRs) and triggering receptor expressed on myeloid cells (TREM-1) activating receptor on monocytes results in the amplification of the inflammatory signal and multiple increase in proinflammatory cytokine production. The dynamics of those receptors expression on monocyte surface of patients with uncomplicated SIRS course followed coronary artery bypass surgery (CABG) was studied. The increase in TLR2 and TREM-1 expression on the first day after CABG induces proinflammatory and amplification potentials of monocytes in that period. The decrease in TLR2 surface expression on the seventh day compared to the preoperative values can be regarded as a mechanism limiting inflammatory response. The highest level of TLR2, TLR4, and TREM-1 surface expression was observed in CD14hiCD16+ monocyte subpopulation, confirming its proinflammatory profile.
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103
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Barreto G, Sillat T, Soininen A, Ylinen P, Salem A, Konttinen YT, Al-Samadi A, Nordström DCE. Do changing toll-like receptor profiles in different layers and grades of osteoarthritis cartilage reflect disease severity? J Rheumatol 2013; 40:695-702. [PMID: 23504385 DOI: 10.3899/jrheum.121159] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Cartilage degeneration in osteoarthritis (OA) leads to release of potential danger signals. The aim of our study was to profile OA cartilage for the Toll-like receptor (TLR) danger signal receptors. METHODS Osteochondral cylinders from total knee replacements were graded using OA Research Society International score and stained for proteoglycans, collagenase-cleaved type II collagen, and TLR 1-10, which were analyzed histomorphometrically. RESULTS Grade 1 OA lesions contained 22%-55% TLR 1-9-positive cells in the surface zone, depending on the TLR type. In Grade 2 TLR, immunoreactivity was 60%-100% (p < 0.01) and it was even higher in Grades 3 and 4 (p < 0.01 vs Grade 1). TLR-positive cells in Grade 1 middle zone were low, 0-19.9%, but were 5.1%-32.7% in Grade 2 (p < 0.01) and 34%-83% in Grades 3-4 samples (p < 0.001). TLR values in Grade 5 were low (14.3%-28.7%; p < 0.001). In Grades 3-4 OA, cartilage matrix stained strongly for TLR. In Grade 1, COL2-3/4M was restricted to chondrocytes, but was increasingly seen in matrix upon progress of OA to Grade 4, and then declined. CONCLUSION Cells in the gliding surface zone are fully equipped with TLR in mild OA. Their proportion increases and extends to the middle or even the deep zone, reflecting OA progression. COL2A-3/4M staining suggests Endo180-mediated intake for intralysosomal degradation by cathepsins in Grade 1, but in higher grades this chondrocyte-mediated clearance fails and the matrix demonstrates extensive collagenase-induced damage. Detached and/or partially degraded matrix components can then act as endogenous danger signals (damage-associated molecular patterns or DAMP) and stimulate increasingly TLR-equipped chondrocytes to inflammation. At the peak inflammatory response, soluble TLR may exert negative feedback, explaining in part the low TLR levels in Grade 5 OA.
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Affiliation(s)
- Gonçalo Barreto
- Department of Medicine, University of Helsinki/Helsinki University Central Hospital, Helsinki, Finland
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104
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Yan D, Chen D, Shen J, Xiao G, van Wijnen AJ, Im HJ. Bovine lactoferricin is anti-inflammatory and anti-catabolic in human articular cartilage and synovium. J Cell Physiol 2013; 228:447-56. [PMID: 22740381 DOI: 10.1002/jcp.24151] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Bovine lactoferricin (LfcinB) is a multi-functional peptide derived from proteolytic cleavage of bovine lactoferrin. LfcinB was found to antagonize the biological effects mediated by angiogenic growth factors such as vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF-2) in endothelial cells. However, the effect of LfcinB on human articular cartilage remained unknown. Here, our findings demonstrate that LfcinB restored the proteoglycan loss promoted by catabolic factors (interleukin-1β) IL-1β and FGF-2 in vitro and ex vivo. Mechanistically, LfcinB attenuated the effects of IL-1β and FGF-2 on the expression of cartilage-degrading enzymes (MMP-1, MMP-3, and MMP-13), destructive cytokines (IL-1β and IL-6), and inflammatory mediators (iNOS and TLR2). LfcinB induced protective cytokine expression (IL-4 and IL-10), and downregulated aggrecanase basal expression. LfcinB specifically activated ERK MAPK and Akt signaling pathways, which may account for its anti-inflammatory activity. We also revealed that LfcinB exerted similar protective effects on human synovial fibroblasts challenged by IL-1β, with minimal cytotoxicity. Collectively, our results suggest that LfcinB possesses potent anti-catabolic and anti-inflammatory bioactivities in human articular tissues, and may be utilized for the prevention and/or treatment of OA in the future.
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Affiliation(s)
- Dongyao Yan
- Department of Biochemistry, Rush University Medical Center, Chicago, Illinois 60612, USA
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105
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Haseeb A, Haqqi TM. Immunopathogenesis of osteoarthritis. Clin Immunol 2013; 146:185-96. [PMID: 23360836 DOI: 10.1016/j.clim.2012.12.011] [Citation(s) in RCA: 282] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 12/17/2012] [Accepted: 12/19/2012] [Indexed: 12/25/2022]
Abstract
Even though osteoarthritis (OA) is mainly considered as a degradative condition of the articular cartilage, there is increasing body of data demonstrating the involvement of all branches of the immune system. Genetic, metabolic or mechanical factors cause an initial injury to the cartilage resulting in release of several cartilage specific auto-antigens, which trigger the activation of immune response. Immune cells including T cells, B cells and macrophages infiltrate the joint tissues, cytokines and chemokines are released from different kinds of cells present in the joint, complement system is activated, and cartilage degrading factors such as matrix metalloproteinases (MMPs) and prostaglandin E2 (PGE2) are released, resulting in further damage to the articular cartilage. There is considerable success in the treatment of rheumatoid arthritis using anti-cytokine therapies. In OA, however, these therapies did not show much effect, highlighting more complex nature of pathogenesis of OA. This needs the development of more novel approaches to treat OA, which may include therapies that act on multiple targets. Plant natural products have this kind of property and may be considered for future drug development efforts. Here we reviewed the studies implicating different components of the immune system in the pathogenesis of OA.
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Affiliation(s)
- Abdul Haseeb
- Department of Anatomy & Neurobiology, Northeast Ohio Medical University, Rootstown, OH 44272, USA
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106
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Gout as autoinflammatory disease: New mechanisms for more appropriated treatment targets. Autoimmun Rev 2012; 12:66-71. [DOI: 10.1016/j.autrev.2012.07.024] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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107
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Effects of Vitamin D Supplementation during the Induction and Progression of Osteoarthritis in a Rat Model. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2012; 2012:156563. [PMID: 23118784 PMCID: PMC3479853 DOI: 10.1155/2012/156563] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 09/04/2012] [Accepted: 09/05/2012] [Indexed: 12/04/2022]
Abstract
Epidemiological studies correlate low levels of vitamin D with the osteoarthritis (OA) progression. Cytokines and metalloproteases play a major role in OA promoting the inflammation and degradation of the cartilage and can be induced through the Toll-like receptor (TLR) pathway. The aim of this study was to evaluate the protective effect of vitamin D supplementation on the development of osteoarthritis (OA) through examining the genetic regulation of TLRs, cytokines, and metalloproteases in chondrocytes as well as the wideness of cartilage in rats with OA. Our results demonstrate that the signaling through TLR-4 is a proinflammatory mechanism in osteoarthritis that drives the upregulation of MMP-3, IL-1β, and TNF-α gene expression, leading to cartilage degradation and inflammation. Vitamin D supplementation had a protective effect during the onset but not during the chronic stage of OA in the rat model.
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108
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Usprech J, Chu G, Giardini-Rosa R, Martin K, Waldman SD. The Therapeutic Potential of Exogenous Adenosine Triphosphate (ATP) for Cartilage Tissue Engineering. Cartilage 2012; 3:364-73. [PMID: 26069646 PMCID: PMC4297147 DOI: 10.1177/1947603512444723] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE While mechanical stimuli can be used to enhance the properties of engineered cartilage, a promising alternative may be to directly harness the underlying mechanotransduction pathways responsible. Our initial studies on the adenosine triphosphate (ATP)-purinergic receptor pathway demonstrated that stimulation by exogenous ATP improved tissue growth and properties but elicited matrix turnover under high doses (250 µM) potentially due to the accumulation of extracellular inorganic pyrophosphate (ePPi). Therefore, the purpose of this study was to identify the mechanism of ATP-mediated catabolism and determine a therapeutic dose to maximize the anabolic effect. DESIGN Isolated bovine articular chondrocytes were seeded in high-density, 3-dimensional culture supplemented with varying doses of ATP for 4 weeks. The effects on biosynthesis, matrix metalloproteinase 13 (MMP-13) protein activity, and PPi accumulation were determined. Separate monolayer experiments were conducted to determine the effect of ePPi on MMP-13 activity. RESULTS High doses of ATP resulted in an increase in ePPi accumulation (by 54%) and MMP-13 activity (by 39%). Monolayer experiments confirmed a link between increased ePPi accumulation and MMP-13 activity, which appeared to require calcium and was inhibited by the MEK1/2 inhibitor U0126. Cultures supplemented with 62.5 to 125 µM ATP favored an anabolic response, which represented the therapeutic dose range. CONCLUSIONS A therapeutic dose range of exogenous ATP to improve the properties of engineered cartilage has been identified, and a possible catabolic mechanism involving excess PPi was determined. Future research into PPi signal transduction and pathological crystal formation is necessary to maximize the beneficial effect of exogenous ATP on chondrocyte cultures.
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Affiliation(s)
- Jenna Usprech
- Department of Mechanical and Materials Engineering, Queen’s University, Kingston, ON, Canada,Human Mobility Research Centre, Kingston General Hospital, Kingston, ON, Canada
| | - Gavin Chu
- Department of Chemical Engineering, Queen’s University, Kingston, ON, Canada
| | | | - Kathleen Martin
- Human Mobility Research Centre, Kingston General Hospital, Kingston, ON, Canada
| | - Stephen D. Waldman
- Department of Mechanical and Materials Engineering, Queen’s University, Kingston, ON, Canada,Human Mobility Research Centre, Kingston General Hospital, Kingston, ON, Canada,Department of Chemical Engineering, Queen’s University, Kingston, ON, Canada
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109
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Abstract
Uric acid is a waste product of purine catabolism. This molecule comes to clinical attention when it nucleates to form crystals of monosodium urate (MSU) in joints or other tissues, and thereby causes the inflammatory disease of gout. Patients with gout frequently suffer from a number of comorbid conditions including hypertension, diabetes mellitus and cardiovascular disease. Why MSU crystals trigger inflammation and are associated with comorbidities of gout has been unclear, but recent studies provide new insights into these issues. Rather than simply being a waste product, uric acid could serve a pathophysiological role as a local alarm signal that alerts the immune system to cell injury and helps to trigger both innate and adaptive immune responses. The inflammatory component of these immune responses is caused when urate crystals trigger both inflammasome-dependent and independent pathways to generate the proinflammatory cytokine IL-1. The resulting bioactive IL-1 stimulates the inflammation of gout and might contribute to the development of other comorbidities. Surprisingly, the same mechanisms underlie the inflammatory response to a number of irritant particles, many of which also cause disease. These new insights help to explain the pathogenesis of gout and point to potential new therapeutic targets for this and other sterile inflammatory diseases.
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110
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Ellman MB, Kim JS, An HS, Chen D, KC R, An J, Dittakavi T, van Wijnen AJ, Cs-Szabo G, Li X, Xiao G, An S, Kim SG, Im HJ. Toll-like receptor adaptor signaling molecule MyD88 on intervertebral disk homeostasis: in vitro, ex vivo studies. Gene 2012; 505:283-90. [PMID: 22692007 DOI: 10.1016/j.gene.2012.06.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 06/04/2012] [Indexed: 12/30/2022]
Abstract
MyD88 is an adapter protein that links toll-like receptors (TLRs) and Interleukin-1 receptors (IL-1Rs) with downstream signaling molecules. The MyD88 has been found to be an essential mediator in the development of osteoarthritis in articular cartilage. However, the role of the MyD88 pathway has yet to be elucidated in the intervertebral disk (IVD). Using in vitro techniques, we analyzed the effect of MyD88 pathway-specific inhibition on the potent inflammatory and catabolic mediator LPS and IL-1 in bovine and human nucleus pulposus (NP) cells by assessing matrix-degrading enzyme expression, including matrix metalloproteases (MMPs) and a disintegrin-like and metalloprotease with thrombospondin motifs (ADAMTS family). We also analyzed inhibition of MyD88 in the regulation of inducible nitric oxide synthase and TLR-2. Finally, we used an ex vivo organ culture model to assess the effects of MyD88 inhibitor (MyD88i) on catabolic factor-induced disk degeneration in mice lumbar disks. In bovine NP cells, MyD88i potently antagonizes LPS- or IL-1-mediated induction of cartilage-degrading enzyme production, including MMP-1, MMP-13, ADAMTS-4, and ADAMTS-5. MyD88i also attenuates the LPS- or IL-1-mediated induction of iNOS and TLR-2 gene expression. Our ex vivo findings reveal inhibition of MyD88 via counteraction of IL-1-mediated proteoglycan depletion. The findings from this study demonstrate the potent anti-inflammatory and anti-catabolic effects of inhibition of MyD88 pathway inhibition on IVD homeostasis, suggesting a potential therapeutic benefit of a MyD88i in degenerative disk disease in the future.
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Affiliation(s)
- Michael B Ellman
- Department of Biochemistry, Rush University Medical Center, Chicago, IL 606124, USA
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111
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Migita K, Koga T, Satomura K, Izumi M, Torigoshi T, Maeda Y, Izumi Y, Jiuchi Y, Miyashita T, Yamasaki S, Aiba Y, Komori A, Nakamura M, Motokawa S, Kawakami A, Nakamura T, Ishibashi H. Serum amyloid A triggers the mosodium urate -mediated mature interleukin-1β production from human synovial fibroblasts. Arthritis Res Ther 2012; 14:R119. [PMID: 22608202 PMCID: PMC3446500 DOI: 10.1186/ar3849] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 04/04/2012] [Accepted: 05/18/2012] [Indexed: 11/23/2022] Open
Abstract
Background Monosodium urate (MSU) has been shown to promote inflammasome activation and interleukin-1β (IL-1β) secretion in monocyte/macrophages, but the cellular pathway and nod-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation in synovial tissues, remain elusive. In this study, we investigated the effects of MSU on synovial fibroblasts to elucidate the process of MSU-mediated synovial inflammation. Methods Human synovial fibroblasts were stimulated with MSU in the presence or absence of serum amyloid A (SAA). The cellular supernatants were analyzed by immunoblotting using anti-IL-1β or anti-caspase-1 antibodies. IL-1β or NLRP3 mRNA expressions were analyzed by real-time PCR or reverse transcription-PCR (RT-PCR) method. Results Neither SAA nor MSU stimulation resulted in IL-1β or interleukin-1α (IL-1α) secretions and pro-IL-1β processing in synovial fibroblasts. However, in SAA-primed synovial fibroblasts, MSU stimulation resulted in the activation of caspase-1 and production of active IL-1β and IL-1α. The effect of SAA on IL-1β induction was impaired in cells by silencing NLRP3 using siRNA or treating with caspase-1 inhibitor. In addition, SAA induced the secretion of cathepsin B and NLRP3 mRNA expression in synovial fibroblasts. Conclusions Our data demonstrate that exposure of human synovial fibroblasts to SAA promotes MSU-mediated caspase-1 activation and IL-1β secretion in the absence of microbial stimulation. These findings provide insight into the molecular processes underlying the synovial inflammatory condition of gout.
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Affiliation(s)
- Kiyoshi Migita
- Department of Rheumatology, Nagasaki Medical Center, Kubara 2-1001-1, Omura, Nagasaki 856-8562, Japan.
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112
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Joo WC, Lee SW, Yang DH, Han JY, Kim MJ. A case of biopsy-proven chronic kidney disease on progression from acute phosphate nephropathy. Kidney Res Clin Pract 2012; 31:124-7. [PMID: 26889420 PMCID: PMC4715133 DOI: 10.1016/j.krcp.2012.04.320] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 01/16/2012] [Accepted: 02/15/2012] [Indexed: 02/06/2023] Open
Abstract
Acute phosphate nephropathy (APhN) following oral sodium phosphate solution (OSP) ingestion as a bowel purgative has been frequently reported. It was recently suggested that APhN could progress to chronic kidney disease (CKD) and a history of APhN might be considered as one of the causes of CKD. However, there are few reports proving APhN as a cause of CKD. Here, we report a case of APhN that progressed to CKD, as proven by renal biopsy.
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Affiliation(s)
- Woo Chul Joo
- Department of Internal Medicine, Nephrology and Hypertension Division, Inha University School of Medicine, Incheon, Korea
| | - Seoung Woo Lee
- Department of Internal Medicine, Nephrology and Hypertension Division, Inha University School of Medicine, Incheon, Korea
| | - Dong Hyuk Yang
- Department of Internal Medicine, Nephrology and Hypertension Division, Inha University School of Medicine, Incheon, Korea
| | - Jee Young Han
- Department of Pathology, Inha University School of Medicine, Incheon, Korea
| | - Moon-Jae Kim
- Department of Internal Medicine, Nephrology and Hypertension Division, Inha University School of Medicine, Incheon, Korea
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113
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Ma Y, Zhou LL, Yan HY, Liu M. Effects of Extracts from Paederia scandens (LOUR.) MERRILL (Rubiaceae) on MSU Crystal-Induced Rats Gouty Arthritis. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2012; 37:669-83. [DOI: 10.1142/s0192415x09007156] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The effects of extract of Paederia scandens (LOUR.) MERRILL (Rubiaceae) (EPS), a Chinese traditional herbal medicine, on inflammatory and immune responses and their mechanisms in MSU crystals-induced (GA) rats were studied. GA rats were established. Ankle joint volume of rats was measured by volume meter; the level of TNF-α and IL-1β was determined by radioimmunoassay. mRNA expressions of TNF-α and IL-1β in synovial tissue of GA rats were analyzed by RT-PCR, and the expression of NF-κB was detected by immunohistochemistry. The administration of EPS (2.25, 4.5 g/kg, ig 9 days) inhibited the inflammatory response in GA rats. The mRNA expressions of TNF-α and IL-1β were also significantly suppressed in synovial tissue. In addition, EPS (2.25, 4.5 g/kg, ig 9 days) inhibited the expression of TNF-α and IL-1β and the biological activity of NF-κB. These results suggested that EPS possesses antiinflammatory effects by modulating pro-inflammatory mediators' production in synovial tissue and inactivating NF-κB pathway transmembrane signal transduction which plays a crucial role in the pathogenesis of this disease.
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Affiliation(s)
- Ying Ma
- Department of Pharmacology, Anhui Medical University, Hefei 230032, China
| | - Lan-Lan Zhou
- Department of Pharmacology, Anhui Medical University, Hefei 230032, China
| | - Hai-Yan Yan
- Department of Pharmacology, Anhui Medical University, Hefei 230032, China
| | - Mei Liu
- Department of Pharmacology, Anhui Medical University, Hefei 230032, China
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114
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Loeser RF, Goldring SR, Scanzello CR, Goldring MB. Osteoarthritis: a disease of the joint as an organ. ACTA ACUST UNITED AC 2012; 64:1697-707. [PMID: 22392533 DOI: 10.1002/art.34453] [Citation(s) in RCA: 1877] [Impact Index Per Article: 156.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Richard F Loeser
- Wake Forest University School of Medicine, Winston-Salem, NC, USA.
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115
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McQueen FM, Chhana A, Dalbeth N. Mechanisms of joint damage in gout: evidence from cellular and imaging studies. Nat Rev Rheumatol 2012; 8:173-81. [DOI: 10.1038/nrrheum.2011.207] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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116
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Guo F, Zhou Z, Dou Y, Tang J, Gao C, Huan J. GEF-H1/RhoA signalling pathway mediates lipopolysaccharide-induced intercellular adhesion molecular-1 expression in endothelial cells via activation of p38 and NF-κB. Cytokine 2012; 57:417-28. [PMID: 22226621 DOI: 10.1016/j.cyto.2011.12.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 11/22/2011] [Accepted: 12/14/2011] [Indexed: 12/14/2022]
Abstract
The purpose of study is to investigate the effects of GEF-H1/RhoA pathway in regulating intercellular adhesion molecule-1 (ICAM-1) expression in lipopolysaccharide (LPS)-activated endothelial cells. Exposure of human umbilical vein endothelial cells (HUVECs) to LPS induced GEF-H1 and ICAM-1 expression in dose- and time-dependent up-regulating manners. Pretreatment with Clostridium difficile toxin B-10463 (TcdB-10463), an inhibitor of Rho activity, reduced LPS-related phosphorylation of p65 at Ser 536 in a dose-dependent manner. Inhibition of TLR4 expression significantly blocked LPS-induced RhoA activity, NF-κB transactivation, GEF-H1 and ICAM-1 expression. Coimmunoprecipitation assay indicated that LPS-activated TLR4 and GEF-H1 formed a signalling complex, suggesting that LPS, acting through TLR4, stimulates GEF-H1 expression and RhoA activity, and thereby induces NF-κB transactivation and ICAM-1 gene expression. However, GEF-H1/RhoA regulates LPS-induced NF-κB transactivation and ICAM-1 expression in a MyD88-independent pathway because inhibition of MyD88 expression could not block LPS-induced RhoA activity. Furthermore, pretreatment with Y-27632, an inhibitor of ROCK, significantly reduced LPS-induced p38, ERK1/2 and p65 phosphorylation, indicating that ROCK acts as an upstream effector of p38 and ERK1/2 to promote LPS-induced NF-κB transactivation and ICAM-1 expression. What is more, the p38 inhibitor (SB203580) but not ERK1/2 inhibitor (PD98059) blocked LPS-induce NF-κB transactivation and ICAM-1 expression, which demonstrates that RhoA mediates LPS-induced NF-κB transactivation and ICAM-1 expression dominantly through p38 but not ERK1/2 activation. In summary, our data suggest that LPS-induced ICAM-1 synthesis in HUVECs is regulated by GEF-H1/RhoA-dependent signaling pathway via activation of p38 and NF-κB.
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Affiliation(s)
- Feng Guo
- Department of Burn and Plastic Surgery, Shanghai Jiao Tong University, School of Medicine, Rui Jin Hospital, Shanghai 230022, China
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117
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GEF-H1-RhoA signaling pathway mediates LPS-induced NF-κB transactivation and IL-8 synthesis in endothelial cells. Mol Immunol 2012; 50:98-107. [PMID: 22226472 DOI: 10.1016/j.molimm.2011.12.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2011] [Revised: 12/21/2011] [Accepted: 12/21/2011] [Indexed: 12/13/2022]
Abstract
Secretion of proinflammatory cytokines by LPS activated endothelial cells contributes substantially to the pathogenesis of sepsis. However, the mechanism involved in this process is not well understood. In the present study, we determined the roles of GEF-H1 (guanine-nucleotide exchange factor-H1)-RhoA signaling in LPS-induced interleukin-8 (IL-8, CXCL8) production in endothelial cells. First, we observed that GEF-H1 expression was upregulated in a dose- and time-dependent manner as consistent with TLR4 (Toll-like receptor 4) expression after LPS stimulation. Afterwards, Clostridium difficile toxin B-10463 (TcdB-10463), an inhibitor of Rho activities, reduced LPS-induced NF-κB phosphorylation. Inhibition of GEF-H1 and RhoA expression reduced LPS-induced NF-κB and p38 phosphorylation. TLR4 knockout blocked LPS-induced activity of RhoA, however, MyD88 knockout did not impair the LPS-induced activity of RhoA. Nevertheless, TLR4 and MyD88 knockout both significantly inhibited transactivation of NF-κB. GEF-H1-RhoA and MyD88 both induced significant changes in NF-κB transactivation and IL-8 synthesis. Co-inhibition of GEF-H1-RhoA and p38 expression produced similar inhibitory effects on LPS-induced NF-κB transactivation and IL-8 synthesis as inhibition of p38 expression alone, thus confirming that activation of p38 was essential for the GEF-H1-RhoA signaling pathway to induce NF-κB transactivation and IL-8 synthesis. Taken together, these results demonstrate that LPS-induced NF-κB activation and IL-8 synthesis in endothelial cells are regulated by the MyD88 pathway and GEF-H1-RhoA pathway.
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118
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Malemud CJ, Sun Y, Pearlman E, Ginley NM, Awadallah A, Wisler BA, Dennis JE. Monosodium Urate and Tumor Necrosis Factor-α Increase Apoptosis in Human Chondrocyte Cultures. ACTA ACUST UNITED AC 2012; 2:113. [PMID: 24660115 PMCID: PMC3959644 DOI: 10.4172/2161-1149.1000113] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Monosodium urate and tumor necrosis factor-α, are two potent mediators of separate inflammatory response pathways in arthritic joints where inflammation may be accompanied by the loss of chondrocyte vitality via apoptosis. To address this possibility in vitro, chondrocyte cultures were employed to determine the extent to which monosodium urate and recombinant TNF-α altered the frequency of apoptotic chondrocytes. Apoptosis as a function of the activation of p38 kinase, C-Jun-terminal kinase, signal transducer and activator of transcription-3 and/or the activity of xanthine oxidase was also studied. Using normal human chondrocytes, monosodium urate or recombinant tumor necrosis factor-α increased the frequency of apoptosis and activity of xanthine oxidase. However, the xanthine oxidase-specific inhibitor, febuxostat, failed to blunt this response. Monosodium urate, tumor necrosis factor-α or the Janus kinase inhibitor, AG-490, increased the frequency of apoptotic nuclei in macroaggregate pellet cultures initiated from juvenile human chondrocytes, but not in pellet cultures derived from mesenchymal stem cells. In OA chondrocytes, activation of p38, C-Jun-NH2-kinase and signal transducer and activator of transcription-3 preceded apoptosis. Activation of signal transducer and activator of transcription-3 also was seen in pellet cultures initiated from juvenile chondrocytes and MSCs incubated with MSU, recombinant tumor necrosis factor-α or febuxostat, but apoptosis was increased only in the pellet cultures derived from juvenile chondrocytes. Although AG-490 or the combination of AG-490 and febuxostat inhibited signal transducer and activator of transcription-3 activation, apoptosis was unaffected. These results showed that recombinant tumor necrosis factor-α, monosodium urate and AG-490 increased apoptosis in normal human chondrocytes, OA chondrocytes and human juvenile chondrocyte pellet cultures, but not in chondrocyte pellet cultures initiated from MSCs. The increased frequency of apoptotic chondrocytes in response to recombinant tumor necrosis factor-α or monosodium urate was not dependent on either activation of STAT3 or the activity of XO.
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Affiliation(s)
- Charles J Malemud
- Department of Medicine/Division of Rheumatic Diseases, Case Western Reserve University School of Medicine, University Hospitals Case Medical Center, Cleveland, Ohio, USA 44106-5076 ; Department of Anatomy, Case Western Reserve University School of Medicine, University Hospitals Case Medical Center, Cleveland, Ohio, USA 44106-5076
| | - Yan Sun
- Department of Ophthalmology and the Visual Sciences Research Center, Case Western Reserve University School of Medicine, University Hospitals Case Medical Center, Cleveland, Ohio, USA 44106
| | - Eric Pearlman
- Department of Ophthalmology and the Visual Sciences Research Center, Case Western Reserve University School of Medicine, University Hospitals Case Medical Center, Cleveland, Ohio, USA 44106
| | - Nell M Ginley
- Department of Orthopaedics, Case Western Reserve University School of Medicine, University Hospitals Case Medical Center, Cleveland, Ohio, USA 44106
| | - Amad Awadallah
- Department of Orthopaedics, Case Western Reserve University School of Medicine, University Hospitals Case Medical Center, Cleveland, Ohio, USA 44106
| | - Bradley A Wisler
- Department of Medicine/Division of Rheumatic Diseases, Case Western Reserve University School of Medicine, University Hospitals Case Medical Center, Cleveland, Ohio, USA 44106-5076
| | - James E Dennis
- Department of Orthopaedics, Case Western Reserve University School of Medicine, University Hospitals Case Medical Center, Cleveland, Ohio, USA 44106 ; Benaroya Research Institute at Virginia Mason, Seattle, WA, USA 98101-2795
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119
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Abstract
The immune system plays an essential role in protecting the host against infections and to accomplish this task has evolved mechanisms to recognize microbes and destroy them. In addition, it monitors the health of cells and responds to ones that have been injured and killed, even if this occurs under sterile conditions. This process is initiated when dying cells expose intracellular molecules that can be recognized by cells of the innate immune system. As a consequence of this recognition, dendritic cells are activated in ways that help to promote T-cell responses to antigens associated with the dying cells. In addition, macrophages are stimulated to produce the cytokine interleukin-1 that then acts on radioresistant parenchymal cells in the host in ways that drive a robust inflammatory response. In addition to dead cells, a number of other sterile particles and altered physiological states can similarly stimulate an inflammatory response and do so through common pathways involving the inflammasome and interleukin-1. These pathways underlie the pathogenesis of a number of diseases.
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Affiliation(s)
- Kenneth L Rock
- Department of Pathology, UMass Medical School, Worcester, MA 01655, USA.
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121
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Goh FG, Midwood KS. Intrinsic danger: activation of Toll-like receptors in rheumatoid arthritis. Rheumatology (Oxford) 2011; 51:7-23. [PMID: 21984766 DOI: 10.1093/rheumatology/ker257] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
RA is a debilitating disorder that manifests as chronic localized synovial and systemic inflammation leading to progressive joint destruction. Recent advances in the molecular basis of RA highlight the role of both the innate and adaptive immune system in disease pathogenesis. Specifically, data obtained from in vivo animal models and ex vivo human tissue explants models has confirmed the central role of Toll-like receptors (TLRs) in RA. TLRs are pattern recognition receptors (PRRs) that constitute one of the primary host defence mechanisms against infectious and non-infectious insult. This receptor family is activated by pathogen-associated molecular patterns (PAMPs) and by damage-associated molecular patterns (DAMPs). DAMPs are host-encoded proteins released during tissue injury and cell death that activate TLRs during sterile inflammation. DAMPs are also proposed to drive aberrant stimulation of TLRs in the RA joint resulting in increased expression of cytokines, chemokines and proteases, perpetuating a vicious inflammatory cycle that constitutes the hallmark chronic inflammation of RA. In this review, we discuss the signalling mechanisms of TLRs, the central function of TLRs in the pathogenesis of RA, the role of endogenous danger signals in driving TLR activation within the context of RA and the current preclinical and clinical strategies available to date in therapeutic targeting of TLRs in RA.
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Affiliation(s)
- Fui G Goh
- Kennedy Institute of Rheumatology Division, Matrix Biology Department, Faculty of Medicine, Imperial College of Science, Technology and Medicine, 65 Aspenlea Road, Hammersmith, London W6 8LH, UK
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122
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Ghaemi-Oskouie F, Shi Y. The role of uric acid as an endogenous danger signal in immunity and inflammation. Curr Rheumatol Rep 2011; 13:160-6. [PMID: 21234729 DOI: 10.1007/s11926-011-0162-1] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Gout is an ancient disease that still plagues us. Its pathogenic culprit, uric acid crystal deposition in tissues, is a strong inflammatory stimulant. In recent years, the mechanisms through which uric acid crystals promote inflammation have been a subject of increasing interest among rheumatologists and immunologists. Uric acid has been identified as an endogenous adjuvant that drives immune responses in the absence of microbial stimulation. Because uric acid is a ubiquitous metabolite that is produced in high quantities upon cellular injury, the ramifications of its effects may be considerable in health and in disease. Uric acid crystals also have been shown to trigger interleukin-1β-mediated inflammation via activation of the NOD-like receptor protein (NLRP)3 inflammasome, a multimolecular complex whose activation appears to be central to many pathological inflammatory conditions. In this article, we review the possible mechanisms of uric acid-mediated inflammation and offer some historical perspectives on what has been learned about the complex effects of a relatively simple substance.
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Affiliation(s)
- Faranak Ghaemi-Oskouie
- Department of Microbiology and Infectious Disease and Immunology Research Group, University of Calgary, 4A18 HRIC, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
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123
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Batsford S, Dunn J, Mihatsch M. Induction of Experimental Arthritis by Borrelial Lipoprotein and CpG Motifs: Are Toll-Like Receptors 2, 4, 9 or CD-14 Involved? Open Rheumatol J 2011; 5:18-23. [PMID: 21804904 PMCID: PMC3141342 DOI: 10.2174/1874312901105010018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 05/02/2011] [Accepted: 05/13/2011] [Indexed: 12/22/2022] Open
Abstract
Bacterial lipoproteins and CpG-DNA are ligands for Toll-Like-Receptors (TLR) 2 and 9 respectively. Both classes of molecules were reported to induce experimental arthritis in rodents following direct intra-articular injection. Here we studied: 1) whether arthritis induction by Outer surface (Lipo)protein A (OspA) (B.burgdorferi) involved the TLR-2 as well as the TLR-4 or the CD-14 receptors in addition, and 2) re-examined the arthritogenic potential of CpG-DNA motifs in mice. Following intra-articular injection of the test substances [20µg recombinant, lipidated OspA; 1nM(6µg) to 10nM(60µg) synthetic CpG-DNA], inflammation was monitored by 99Tc scintigraphy (ratio left/right knee joint uptake > 1.1 indicates inflammation) and by histology. Lipoprotein OspA induced severe, acute arthritis in TLR-2+/+ w.t. but not in TLR-2-/- mice (p<0.01). There were no significant differences in the severity of arthritis induced in TLR-4+/+ w.t. and TLR-4-/- mutant mice, or between CD14+/+ w.t. and CD14-/- mice. CpG-DNA (1or 10 nM) did not cause notable inflammation in C57BL/6 mice; 99Tc ratios were < 1.0 and histology showed only minimal changes. Induction of arthritis by the OspA lipoprotein of B.burgdorferi involves the TLR-2 receptor, no evidence for additional participation of TLR-4 or CD14 receptors was found. Intra-articular injection of CpG-DNA did not produce manifest joint injury in mice, at variance with previous reports.
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Affiliation(s)
- Stephen Batsford
- Department of Immunology, Institute of Medical Microbiology and Hygiene, Albert Ludwigs University Freiburg, D-79104 Germany
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124
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Abstract
PURPOSE OF REVIEW Calcium pyrophosphate dihydrate (CPPD) and basic calcium phosphate (BCP) crystals are common components of osteoarthritic joint fluids and tissues. Why these crystals form and how they contribute to joint damage in osteoarthritis remain unclear. With renewed interest in inflammation as a key component of osteoarthritis the role of calcium-containing crystals in this common disease warrants re-examination. RECENT FINDINGS There is ample evidence supporting a pathogenic role for inflammation in osteoarthritis, and the innate immune system likely participates in this inflammatory process. Recent work reinforces the almost universal existence of calcium-containing crystals in tissues from patients with end-stage osteoarthritis. Calcium-containing crystals may contribute to inflammation in osteoarthritis tissues through their direct interactions with components of the innate immune system, as well as by inducing or amplifying other inflammatory signals. SUMMARY There is increasing evidence that calcium-containing crystals contribute to osteoarthritis and their inflammatory properties may mediate detrimental effects through innate immunity signals. Calcium-containing crystals may thus represent important therapeutic targets in osteoarthritis.
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125
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Abstract
Toll-like receptors (TLRs), a family of pattern recognition receptors, recognize and respond to conserved components of microbes and play a crucial role in both innate and adaptive immunity. In addition to binding exogenous ligands derived from pathogens, TLRs interact with endogenous molecules released from damaged tissues or dead cells and regulate many sterile inflammation processes. Putative endogenous TLR ligands include proteins and peptides, polysaccharides and proteoglycan, nucleic acids and phospholipids, which are cellular components, particularly extracellular matrix degradation products. Accumulating evidence demonstrates that endogenous ligand-mediated TLR signalling is involved in pathological conditions such as tissue injury, repair and regeneration; autoimmune diseases and tumorigenesis. The ability of TLRs to recognize endogenous stimulators appears to be essential to their function in regulating non-infectious inflammation. In this review, we summarize current knowledge of endogenous TLR ligands and discuss the biological significance of TLR signalling triggered by endogenous ligands in several sterile inflammation conditions.
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Affiliation(s)
- Li Yu
- Department of Pathology, the First Affiliated Hospital, Sun Yat-sen (Zhongshan) University, Guangzhou, P.R. China
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126
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Inhaled therapies for tuberculosis and the relevance of activation of lung macrophages by particulate drug-delivery systems. Ther Deliv 2011; 2:753-68. [DOI: 10.4155/tde.11.34] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Pathogenic strains of Mycobacterium tuberculosis (Mtb) induce ‘alternative activation’ of lung macrophages that they colonize, in order to create conditions that promote the establishment and progression of infection. There is some evidence to indicate that such macrophages may be rescued from alternative activation by inhalable microparticles containing a variety of drugs. This review summarizes the experience of various groups of researchers, relating to observations of induction of a number of classical macrophage activation pathways. Restoration of a ‘respiratory burst’ and upregulation of reactive oxygen species and nitrogen intermediates through the phagocyte oxidase and nitric oxide synthetase enzyme systems; induction of proinflammatory macrophage cytokines; and finally induction of apoptosis rather than necrosis of the infected macrophage are discussed. It is suggested that there is scope to co-opt host responses in the management of tuberculosis, through the route of pulmonary drug delivery.
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127
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Santegoets KCM, van Bon L, van den Berg WB, Wenink MH, Radstake TRDJ. Toll-like receptors in rheumatic diseases: are we paying a high price for our defense against bugs? FEBS Lett 2011; 585:3660-6. [PMID: 21513712 DOI: 10.1016/j.febslet.2011.04.028] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 04/11/2011] [Accepted: 04/12/2011] [Indexed: 12/31/2022]
Abstract
In the last decade Toll-like receptor (TLR) research has led to new insights in the pathogenesis of many rheumatic diseases. In autoimmune diseases like systemic lupus erythematosus, rheumatoid arthritis and systemic sclerosis TLR signaling is likely to be involved in tolerance breakthrough and chronic inflammation via combined Fc gamma receptors and TLR recognition of immune complexes. Furthermore, inflammatory diseases like psoriatic arthritis and gout also show more and more evidence for TLR involvement. In this review we will discuss the involvement of TLR signaling in several rheumatic diseases and stress their similarities and differences based on recent findings.
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Affiliation(s)
- K C M Santegoets
- Department of Rheumatology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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128
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Khoshniat S, Bourgine A, Julien M, Petit M, Pilet P, Rouillon T, Masson M, Gatius M, Weiss P, Guicheux J, Beck L. Phosphate-dependent stimulation of MGP and OPN expression in osteoblasts via the ERK1/2 pathway is modulated by calcium. Bone 2011; 48:894-902. [PMID: 21147284 DOI: 10.1016/j.bone.2010.12.002] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 12/01/2010] [Accepted: 12/02/2010] [Indexed: 12/31/2022]
Abstract
Inorganic phosphate (Pi) acts as a signaling molecule in bone-forming cells, affecting cell functions and gene expression. Particularly, Pi stimulates the expression of mineralization-associated genes such as matrix gla protein (MGP) and osteopontin (OPN) through the ERK1/2 pathway. With respect to the presence of elevated extracellular calcium and Pi levels during bone remodeling, we questioned whether calcium might play a role in the Pi-dependent effects in osteoblasts. We first showed by Western blot and real-time PCR that the concomitant presence of 10 mM Pi and 1.8 mM calcium is required to stimulate ERK1/2 phosphorylation and MGP/OPN genes expression. The mechanisms involved in the cellular effects of calcium in the presence of Pi were subsequently examined. Firstly, the use of the calcium-sensing receptor (CaSR) agonist gadolinium and the G-protein inhibitor pertussis toxin enabled us to determine that a CaSR mechanism is not involved in the Pi and calcium mediated cellular effects. By transmission electron microscopy, we next demonstrated that adding 10mM Pi to the culture medium containing 1.8mM calcium led to the formation calcium phosphate precipitates (CaPp). Moreover, treatment of osteoblasts with exogenous pre-synthesized CaPp stimulated ERK1/2 phosphorylation and MGP/OPN genes expression. In spite of high extracellular calcium and Pi concentrations, this stimulation was blunted in the presence of phosphocitrate, an inhibitor of crystal formation. Finally, we showed that despite that CaPp are not endocytosed, their effect on ERK1/2 phosphorylation and MGP/OPN genes expression were dependent on lipid rafts integrity. In summary, we showed that calcium is required for Pi-dependent ERK1/2 phosphorylation and regulation of mineralization-associated genes in osteoblasts and that its effect could originate from extracellular-related effects of CaPp that are dependent on the integrity of lipid rafts.
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Affiliation(s)
- S Khoshniat
- Group STEP Skeletal Tissue Engineering and Physiopathology, Centre for Osteoarticular and Dental Tissue Engineering (LIOAD), INSERM, U791, Nantes, F-44042, France
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129
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Di Paola R, Mazzon E, Galuppo M, Esposito E, Bramanti P, Fink MP, Cuzzocrea S. Ethyl pyruvate therapy attenuates experimental severe arthritis caused by type II collagen (CII) in the mouse (CIA). Int J Immunopathol Pharmacol 2011; 23:1087-98. [PMID: 21244758 DOI: 10.1177/039463201002300413] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This study tested the hypothesis that ethyl pyruvate (EP), a simple aliphatic ester with anti-inflammatory effects, can reduce type II collagen-induced mouse arthritis (CIA). DBA/1J mice were used for the study, developing erosive hind paw arthritis when immunized with CII in an emulsion in complete Freund?s adjuvant (CFA). The incidence of CIA was 100 percent by day 28 in the CII-challenged mice, and the severity of CIA progressed over a 35-day period with radiographic evaluation revealing focal resorption of bone. The histopathology of CIA included erosion of the cartilage at the joint margins. EP-treatment (40 mg/kg/day i.p.) starting at the onset of arthritis (day 25) ameliorated the clinical signs at days 26-35 and improved histological status in the joint and paw. Immunohistochemical analysis for nitrotyrosine, poly (ADP-ribose) (PAR), inducible nitric oxide synthase (iNOS) revealed a positive staining in inflamed joints from mice subjected to CIA, while no staining was observed for HO-1 and Nrf-2 in the same group. The degree of staining for nitrotyrosine, PAR, iNOS, was significantly reduced in CII-challenged mice treated with the EP. Immuno-positive-staining for HO-1 and Nrf-2 was observed instead, in joints obtained from the EP-treated group. Plasma levels of TNF-α, IL-6 and the joint tissue levels of macrophage inflammatory protein (MIP)-1α and MIP-2 were also significantly reduced by EP treatment. Thirty-five days after immunization, EP-treatment significantly increased plasma levels of IL-10. These data demonstrate that EP treatment exerts an anti-inflammatory effect during chronic inflammation and is able to ameliorate the tissue damage associated with CIA.
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Affiliation(s)
- R Di Paola
- IRCCS Centro Neurolesi Bonino-Pulejo, Messina, Italy
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130
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Bourgine A, Beck L, Khoshniat S, Wauquier F, Oliver L, Hue E, Alliot-Licht B, Weiss P, Guicheux J, Wittrant Y. Inorganic phosphate stimulates apoptosis in murine MO6-G3 odontoblast-like cells. Arch Oral Biol 2011; 56:977-83. [PMID: 21435634 DOI: 10.1016/j.archoralbio.2011.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 02/11/2011] [Accepted: 03/01/2011] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Dental pathologies such as caries are the most prevalent disease worldwide with infectious and social complications. During the process of caries formation, the tooth is degraded and demineralization of enamel and dentine leads to the release of large amounts of inorganic phosphate (Pi) within dental tubuli. As Pi has been shown to induce apoptosis in skeletal cells, including osteoblasts and chondrocytes, we questioned whether high concentrations of Pi could affect odontoblast viability, proliferation and apoptosis. DESIGN Using the odontoblast-like MO6-G3 cell line as a model, we used cell counting and MTS-based colorimetric assays to measure cell viability and proliferation. Apoptosis was assessed using Hoechst nuclei staining and detection of the early apoptotic markers annexin V and Apo2.7. RESULTS We show for the first time that a high Pi concentration (7 mM) induced a decrease in odontoblast viability and proliferation together with a large increase in apoptosis. These effects were blunted in calcium-free medium, possibly due to the formation of calcium-phosphate crystals in the presence of high Pi concentrations. CONCLUSION This study contributes to clarifying the effect of Pi on odontoblast viability and apoptosis, which may improve our understanding of the role of Pi during caries formation.
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Affiliation(s)
- A Bourgine
- INSERM, U791, Centre for Osteoarticular and Dental Tissue Engineering (LIOAD), Group STEP Skeletal Tissue Engineering and Physiopathology, Nantes F-44042, France
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131
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Papathanasiou I, Malizos KN, Poultsides L, Karachalios T, Oikonomou P, Tsezou A. The catabolic role of toll-like receptor 2 (TLR-2) mediated by the NF-κB pathway in septic arthritis. J Orthop Res 2011; 29:247-51. [PMID: 20740673 DOI: 10.1002/jor.21239] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 07/09/2010] [Indexed: 02/04/2023]
Abstract
Toll-like receptors (TLRs) are involved in mediating cell activation on stimulation with microbial components. Our objective was to investigate the role of TLR-2 mediated by the NF-κB pathway in septic arthritic chondrocytes. TLR-1, -2, and -6 mRNA expression levels were investigated in septic and normal chondrocytes using real-time reverse transcription-PCR. TLR-2 and MMP-13 mRNA and protein levels were measured using real-time PCR and Western blot analysis, respectively. Blocking TLR-2 mRNA expression was performed using small interfering RNA (siRNA) against TLR-2 and subsequently MMP-3, MMP-13, IL-1β, and IL-6 mRNA levels, as well as p65 NF-κB, IkBα, and MMP-13 protein levels were evaluated using real-time PCR and Western blot analysis. IL-6 protein levels were measured using ELISA assay. We observed that TLR-1, -2, and -6 mRNA expression levels were significantly higher in septic compared to normal chondrocytes. MMP-13 mRNA and protein expressions were also significantly upregulated in septic arthritic cartilage. Blocking TLR-2 mRNA expression in septic chondrocytes resulted in significant increase of inactivated nonphosphorylated p65 NF-κB and IkBα protein levels and reduction in MMP-13, IL-1β, and IL-6 expression. Our findings suggest the pro-inflammatory and catabolic role of TLR-2 mediated by the NF-κB pathway in septic arthritis. Modulation of TLR-mediated signaling may be a potential therapeutic strategy for the prevention of postinfectious cartilage degradation in articular joints.
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Affiliation(s)
- Ioanna Papathanasiou
- Medical School, Laboratory of Cytogenetics and Molecular Genetics, University of Thessaly, Larissa, Greece
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132
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Ea HK, Nguyen C, Bazin D, Bianchi A, Guicheux J, Reboul P, Daudon M, Lioté F. Articular cartilage calcification in osteoarthritis: insights into crystal-induced stress. ACTA ACUST UNITED AC 2011; 63:10-8. [PMID: 20862682 DOI: 10.1002/art.27761] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Hang-Korng Ea
- INSERM UMR-S 606, Hôpital Lariboisière, Assistance Publique-Hôpitaux de Paris, PRES Sorbonne Paris-Cité, and Université Paris Denis Diderot, Paris, France.
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133
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Abstract
Osteoarthritis (OA) is the most common cause of chronic disability in older adults. Although classically considered a "wear and tear" degenerative condition of articular joints, recent studies have demonstrated an inflammatory component to OA that includes increased activity of several cytokines and chemokines in joint tissues that drive production of matrix-degrading enzymes. Rather than directly causing OA, aging changes in the musculoskeletal system contribute to the development of OA by making the joint more susceptible to the effects of other OA risk factors that include abnormal biomechanics, joint injury, genetics, and obesity. Age-related sarcopenia and increased bone turnover may also contribute to the development of OA. Understanding the basic mechanisms by which aging affects joint tissues should provide new targets for slowing or preventing the development of OA.
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Affiliation(s)
- Richard F Loeser
- Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
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134
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Dubchak N, Falasca GF. New and improved strategies for the treatment of gout. Int J Nephrol Renovasc Dis 2010; 3:145-66. [PMID: 21694941 PMCID: PMC3108771 DOI: 10.2147/ijnrd.s6048] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Indexed: 12/16/2022] Open
Abstract
The Western world appears to be in the midst of the third great gout epidemic of all time. In this century, gout is increasing in prevalence despite an increased understanding of its risk factors and pathophysiology, and the availability of reasonably effective treatment. The main cultural factors responsible for this appear to be diet, obesity, ethanol use and medications. Excess fructose consumption is a newly recognized modifiable risk factor. The debate has been renewed concerning hyperuricemia as an independent risk factor for renal insufficiency and cardiovascular disease. Prevention is still rooted in lifestyle choices. Existing treatments have proven to be unsatisfactory in many patients with comorbidities. New treatments are available today and on the horizon for tomorrow, which offer a better quality of life for gout sufferers. These include febuxostat, a nonpurine inhibitor of xanthine oxidase with a potentially better combination of efficacy and safety than allopurinol, and investigational inhibitors of URAT-1, an anion exchanger in the proximal tubule that is critical for uric acid homeostasis. New abortive treatments include interleukin-1 antagonists that can cut short the acute attack in 1 to 2 days in persons who cannot take nonsteroidal anti-inflammatory drugs, colchicine or corticosteroids. Lastly, newer formulations of uricase have the ability to dissolve destructive tophi over weeks or months in patients who cannot use currently available hypouricemic agents. Diagnostically, ultrasound and magnetic resonance imaging offer advanced ways to diagnose gout noninvasively, and just as importantly, a way to follow the progress of tophus dissolution. The close association of hyperuricemia with metabolic syndrome, hypertension and renal insufficiency ensures that nephrologists will see increasing numbers of gout-afflicted patients.
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Affiliation(s)
- Natalie Dubchak
- Division of Rheumatology, Cooper University Hospital, UMDNJ – Robert Wood Johnson Medical School at Camden, Camden, NJ, USA
| | - Gerald F Falasca
- Division of Rheumatology, Cooper University Hospital, UMDNJ – Robert Wood Johnson Medical School at Camden, Camden, NJ, USA
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135
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Maruyama K, Selmani Z, Ishii H, Yamaguchi K. Innate immunity and cancer therapy. Int Immunopharmacol 2010; 11:350-7. [PMID: 20955832 DOI: 10.1016/j.intimp.2010.09.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 09/16/2010] [Accepted: 09/18/2010] [Indexed: 02/07/2023]
Abstract
Classical cancer immunotherapy utilizes the immune response against microbial components, and a sequence of immune responses produce antitumor effects. The identification of mammalian Toll-like receptors (TLRs), receptors for microbial components, has shed light on antigen recognition by the innate immune system and provided a molecular basis for our understanding of the relationship between innate immunity and antitumor activity. However, accumulating evidence has revealed another important role of TLRs in maintaining tissue homeostasis and has also shown that tumor cells utilize this function to create favorable conditions for growth and survival, suggesting that TLR signaling acts as a double-edged sword in cancer therapy. In this review, innate immunity-based cancer therapy will be discussed with special reference to TLR-targeting drugs.
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Affiliation(s)
- Kouji Maruyama
- Experimental Animal Facility, Shizuoka Cancer Center Research Institute, 1007 Shimonagakubo, Sunto-gun, Nagaizumi-cho, Shizuoka 411-8777, Japan.
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136
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Liu-Bryan R, Terkeltaub R. Chondrocyte innate immune myeloid differentiation factor 88-dependent signaling drives procatabolic effects of the endogenous Toll-like receptor 2/Toll-like receptor 4 ligands low molecular weight hyaluronan and high mobility group box chromosomal protein 1 in mice. ACTA ACUST UNITED AC 2010; 62:2004-12. [PMID: 20506365 DOI: 10.1002/art.27475] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Toll-like receptor 2 (TLR-2)/TLR-4-mediated innate immunity serves as a frontline antimicrobial host defense, but also modulates tissue remodeling and repair responses to endogenous ligands released during low-grade inflammation. We undertook the present study to assess whether the endogenous TLR-2/TLR-4 ligands low molecular weight hyaluronan (LMW-HA) and high mobility group box chromosomal protein 1 (HMGB-1), which are increased in osteoarthritic (OA) joints, drive procatabolic chondrocyte responses dependent on TLR-2 and TLR-4 signaling through the cytosolic adaptor myeloid differentiation factor 88 (MyD88). METHODS We studied mature femoral head cap cartilage explants and immature primary knee articular chondrocytes from TLR-2/TLR-4-double-knockout, MyD88-knockout, and congenic wild-type mice. Generation of nitric oxide (NO), degradation of hyaluronan, release of HMGB-1, matrix metalloproteinase 3 (MMP-3), and MMP-13, and protein expression of type X collagen were assessed by Griess reaction and Western blotting analyses. Expression of messenger RNA for type II and type X collagen, MMP-13, and RUNX-2 was examined by real-time quantitative reverse transcription-polymerase chain reaction. RESULTS Interleukin-1beta and TLR-2 and TLR-4 ligands induced both HMGB-1 release from chondrocytes and extracellular LMW-HA generation in normal chondrocytes. TLR-2/TLR-4(-/-) and MyD88(-/-) mouse cartilage explants and chondrocytes lost the capacity to mount procatabolic responses to both LMW-HA and HMGB-1, demonstrated by >95% suppression of NO production (P < 0.01), and attenuated induction of MMP-3 and MMP-13. Combined deficiency of TLR-2/TLR-4, or of MyD88 alone, also attenuated release of NO and blunted induction of MMP-3 and MMP-13 release. MyD88 was necessary for HMGB-1 and hyaluronidase 2 (which generates LMW-HA) to induce chondrocyte hypertrophy, which is implicated in OA progression. CONCLUSION MyD88-dependent TLR-2/TLR-4 signaling is essential for procatabolic responses to LMW-HA and HMGB-1, and MyD88 drives chondrocyte hypertrophy. Therefore, LMW-HA and HMGB-1 act as innate immune cytokine-like signals with the potential to modulate chondrocyte differentiation and function in OA progression.
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Affiliation(s)
- Ru Liu-Bryan
- VA Medical Center, San Diego, California 92161, USA.
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137
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Hoffman HM, Scott P, Mueller JL, Misaghi A, Stevens S, Yancopoulos GD, Murphy A, Valenzuela DM, Liu-Bryan R. Role of the leucine-rich repeat domain of cryopyrin/NALP3 in monosodium urate crystal-induced inflammation in mice. ACTA ACUST UNITED AC 2010; 62:2170-9. [PMID: 20506351 DOI: 10.1002/art.27456] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE The mechanism by which monosodium urate monohydrate (MSU) crystals intracellularly activate the cryopyrin inflammasome is unknown. The aim of this study was to use a mouse molecular genetics-based approach to test whether the leucine-rich repeat (LRR) domain of cryopyrin is required for MSU crystal-induced inflammation. METHODS Cryopyrin-knockout lacZ (Cryo(-Z/-Z)) mice and mice with the cryopyrin LRR domain deleted and fused to the lacZ reporter (Cryo(DeltaLRR Z/DeltaLRR Z)) were generated using bacterial artificial chromosome-based targeting vectors, which allow for large genomic deletions. Bone marrow-derived macrophages from Cryo(DeltaLRR Z/DeltaLRR Z) mice, Cryo(-Z/-Z) mice, and congenic wild-type (WT) mice were challenged with endotoxin-free MSU crystals under serum-free conditions. Phagocytosis and cytokine expression were assessed by flow cytometry and enzyme-linked immunosorbent assay. MSU crystals also were injected into mouse synovial-like subcutaneous air pouches. The in vivo inflammatory responses were examined. RESULTS Release of interleukin-1beta (IL-1beta), but not CXCL1 and tumor necrosis factor alpha, was impaired in Cryo(DeltaLRR Z/DeltaLRR Z) and Cryo(-Z/-Z) mouse bone marrow-derived macrophages compared with WT mouse bone marrow-derived macrophages in response to not only MSU crystals but also other known stimuli that activate the cryopyrin inflammasome. In addition, a comparable percentage of MSU crystals taken up by each type of bone marrow-derived macrophage was observed. Moreover, total leukocyte infiltration in the air pouch and IL-1beta production were attenuated in Cryo(-Z/-Z) and Cryo(DeltaLRR Z/DeltaLRR Z) mice at 6 hours postinjection of MSU crystals compared with WT mice. CONCLUSION MSU crystal-induced inflammatory responses were comparably attenuated both in vitro and in vivo in Cryo(DeltaLRR Z/DeltaLRR Z) and Cryo(-Z/-Z) mice. Hence, the LRR domain of cryopyrin plays a role in mediating MSU crystal-induced inflammation in this model.
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138
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Drexler SK, Sacre SM, Foxwell BM. Toll-like receptors: a new target in rheumatoid arthritis? Expert Rev Clin Immunol 2010; 2:585-99. [PMID: 20477615 DOI: 10.1586/1744666x.2.4.585] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Rheumatoid arthritis (RA) is one of the most prevalent autoimmune diseases. It is characterized by chronic inflammation of the joint leading to its destruction. Although the initiating cause remains elusive, environmental factors and genetic background are known to contribute to the etiology of RA. The role of Toll-like receptors (TLRs) in innate immunity and their ability to recognize microbial products has been well characterized. TLRs are able to recognize endogenous molecules released upon cell damage and necrosis, and are present in RA synovial fluid. Although it appears unlikely that a pathogen underlies the pathogenesis or progression of RA, the release of endogenous TLR ligands during inflammation may activate TLRs and perpetuate the disease. An increasing body of circumstantial evidence implicates TLR signaling in RA, although, at present, their involvement is not defined comprehensively. Targeting individual TLRs or their signaling transducers may provide a more specific therapy without global suppression of the immune system.
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Affiliation(s)
- Stefan K Drexler
- Imperial College of Science, Technology and Medicine, Kennedy Institute of Rheumatology Division, Faculty of Medicine, 1 Aspenlea Road, Hammersmith, London,W6 8LH, UK.
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139
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Abstract
Uric acid crystals [monosodium urate (MSU)] have emerged as an important factor for both gouty arthritis and immune regulation. This simple crystalline structure appears to activate innate host defense mechanisms in multiple ways and triggers robust inflammation and immune activation. The recognition mechanisms of MSU following its phase change from soluble uric acid are diverse, involving both protein receptors and non-specific plasma membrane attachment. Upon contact with host cells, MSU induces a set of membrane events that trigger Syk and PI3K activation, phagocytosis, and cytokine production. Having entered the cell, MSU further triggers NALP3 inflammasome activation and induces the production of IL-1 beta, likely inducing a full spectrum of inflammation. This review describes the recognition mechanisms and activation pathways involved in MSU-mediated inflammation and adjuvanticity and hypothesizes that direct membrane binding by solid surfaces, such as MSU, may function as a generic mechanism in tissue responses to particulate and crystalline structures.
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Affiliation(s)
- Yan Shi
- Department of Microbiology and Infectious Diseases, and Immunology Research Group, Faculty of Medicine, University of Calgary, Calgary, AB, Canada.
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140
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Whole-body MRI in the childhood form of hypophosphatasia. Rheumatol Int 2010; 31:1315-20. [PMID: 20383509 DOI: 10.1007/s00296-010-1493-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2010] [Accepted: 03/27/2010] [Indexed: 10/19/2022]
Abstract
Hypophosphatasia (HPP) is a rare inborn error of bone metabolism caused by various defects in the gene coding for the tissue-nonspecific alkaline phosphatase (TNSAP). It results in a reduced activity of the TNSAP and elevated concentrations of its substrates, including inorganic pyrophosphate. Clinical features of HPP include defective bone mineralisation with bone deformities, fractures and chronic non-bacterial osteomyelitis. Renal damage due to calcification, craniosynostosis and dental abnormalities with premature loss of dentition are further complications. Until now, detailed descriptions of whole-body magnetic resonance imaging (WB-MRI) in HPP do not exist. Here, we analysed WB-MRIs of 4 children with the childhood form of HPP. Deformities and defects of the long bones could be seen. All patients showed radiological lesions in the metaphyses of the long bones predominantly in the lower extremities being consistent with hyperaemia and oedema. Differential diagnosis includes an inflammatory process being active in these locations.
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141
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Affiliation(s)
- Oana Popa‐Nita
- Centre de Recherche en Rhumatologie et Immunologie du Centre de Recherche du CHUL‐CHUQ, Department of Microbiology and Immunology, Faculty of Medicine, Laval University Québec Canada
| | - Paul H Naccache
- Centre de Recherche en Rhumatologie et Immunologie du Centre de Recherche du CHUL‐CHUQ, Department of Microbiology and Immunology, Faculty of Medicine, Laval University Québec Canada
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142
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Liu YZ, Jackson AP, Cosgrove SD. Contribution of calcium-containing crystals to cartilage degradation and synovial inflammation in osteoarthritis. Osteoarthritis Cartilage 2009; 17:1333-40. [PMID: 19447216 DOI: 10.1016/j.joca.2009.04.022] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 04/09/2009] [Accepted: 04/28/2009] [Indexed: 02/02/2023]
Abstract
OBJECTIVES The role of calcium phosphate and pyrophosphate crystals in osteoarthritis (OA) is unclear: are they a symptom of the damage that occurs to the joint or a key intermediate in the progression of inflammation and joint damage that occurs in OA? The proinflammatory and catabolic response of synthetic calcium phosphate and pyrophosphate crystals and crystals extracted from human osteoarthritic knee cartilage has been investigated. The crystal forms eliciting a response have been characterised allowing a comparison of the biological effects of synthetic and native calcium crystals on human osteoarthritic chondrocytes and synoviocytes to be carried out. METHODS Calcium phosphate and pyrophosphate crystals were synthesised in vitro and their crystal forms characterised by X-ray powder diffraction (XRPD). The inorganic crystalline material present in human osteoarthritic cartilage was extracted and its structural composition elucidated by XRPD. These crystals were applied to human primary osteoarthritic chondrocytes and synoviocytes and the production of proinflammatory and catabolic mediators measured. RESULTS The crystals extracted from human osteoarthritic knee cartilage were identified as consisting of a mixture of monoclinic and triclinic calcium pyrophosphate dihydrate (m-CPPD and t-CPPD). These crystals elicited an inflammatory and catabolic response in human primary osteoarthritic chondrocytes and synoviocytes as measured by an increase in nitric oxide (NO), matrix metalloproteinase 13 (MMP-13) and prostaglandin E2 (PGE(2)) production. NO, MMP-13 and PGE(2) production was also increased when the synthetic calcium hydrogen phosphate dihydrate (DCPD) and calcium pyrophosphate hydrates were applied to the cells. CONCLUSIONS Crystals extracted from human osteoarthritic knee cartilage induce the production of proinflammatory and catabolic mediators (NO, MMP-13 and PGE(2)) in human primary chondrocytes and synoviocytes. Synthetic calcium phosphate and pyrophosphate crystals elicit a similar response in those cells. Our findings suggest that these crystals could contribute to cartilage degradation and synovitis in OA.
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Affiliation(s)
- Y Z Liu
- Department of Bioscience, AstraZeneca R&D Charnwood, Bakewell Road, Loughborough, UK.
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143
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Abstract
PURPOSE OF REVIEW Calcium pyrophosphate dihydrate and basic calcium phosphate crystals are the two most common calcium-containing crystals involved in rheumatic diseases. Recent literature concerning their role in the pathogenesis of osteoarthritis is reviewed. RECENT FINDINGS In some instances, these calcium crystals might worsen osteoarthritis cartilage destruction. Laboratory investigations have identified determinants of cartilage calcification, especially a better characterization of matrix vesicle content and a better understanding of the regulation of inorganic pyrophosphate and phosphate concentration. In-vitro studies have highlighted new pathogenic mechanisms of calcium crystal-induced cell activation. Several intracellular signalling pathways are activated by calcium crystals. Recent studies suggested the implication of the inflammasome complex and a pivotal role for IL-1 in pseudogout attacks and chondrocyte apoptosis in basic calcium phosphate crystal-related arthropathies. SUMMARY Animal models of osteoarthritis and in-vitro studies using calcium pyrophosphate dihydrate and basic calcium phosphate crystals will improve our knowledge of these common crystals and could suggest new targets for drugs, as these common diseases are 'orphan' with respect to therapy.
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144
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Borysiewicz E, Fil D, Konat GW. Rho proteins are negative regulators of TLR2, TLR3, and TLR4 signaling in astrocytes. J Neurosci Res 2009; 87:1565-72. [PMID: 19115402 DOI: 10.1002/jnr.21968] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The family of Toll-like receptors (TLRs) expressed by innate immune cells recognizes a spectrum of microbial components as well as molecules released from injured tissues. TLR ligation activates intracellular signaling cascades that culminate in the up-regulation of proinflammatory genes. We have recently demonstrated that the up-regulation of inflammatory cytokines mediated by TLR4 in astrocytes is negatively controlled by the monomeric GTPases of Rho subfamily. The present study was undertaken to examine further the involvement of Rho proteins in the inflammatory response of astrocytes elicited by the ligation of three TLRs that use divergent signaling pathways. Astrocyte cultures established from newborn rat brains were challenged with ligands of TLR2, TLR3, and TLR4. The expression of genes encoding interleukin (IL)-1beta, IL-6, tumor necrosis factor-alpha (TNFalpha), interferon-beta (IFNbeta), and inducible nitric oxide synthase (NOS2) was up-regulated 24 hr after the challenge as determined by real-time RT-PCR. Pretreatment of the cells with toxin B, which specifically inactivates Rho proteins, enhanced the up-regulation of gene expression. The extent of this enhancement was both receptor and gene dependent. The enhancing effect of Rho protein inactivation was also evident at the protein level of IL-6 and NOS2 as revealed by ELISA and immunoblot analyses, respectively. These results suggest that Rho proteins control TLR-mediated up-regulation of inflammatory genes in astrocytes by interfering with multiple events along the signaling pathways.
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Affiliation(s)
- Elizabeth Borysiewicz
- Department of Neurobiology and Anatomy, West Virginia University School of Medicine, Morgantown, West Virginia 26506, USA
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145
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Announ N, Palmer G, Guerne PA, Gabay C. Anakinra is a possible alternative in the treatment and prevention of acute attacks of pseudogout in end-stage renal failure. Joint Bone Spine 2009; 76:424-6. [PMID: 19289295 DOI: 10.1016/j.jbspin.2009.01.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Accepted: 01/07/2009] [Indexed: 12/31/2022]
Abstract
We describe the case of a 71-year-old man with recurrent pseudogout attacks affecting multiple joints. He had end-stage renal failure that contra-indicated the use of non-steroidal anti-inflammatory drugs and was resistant to therapy with glucocorticoids. Based on the recent findings that interleukin (IL)-1beta is involved in crystal-induced inflammation, the patient received anakinra, a specific IL-1 inhibitor, in order to treat an acute attack of pseudogout. In addition, anakinra was administered as preventive therapy 3days per week after each hemodialysis session. Under this treatment, he did not present any severe episode of arthritis after a follow-up of 8 months. This observation suggests that anakinra is efficacious and safe for the prevention of crystal-induced arthritis in patients with severe renal failure.
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Affiliation(s)
- Nadia Announ
- Division of Rheumatology, Department of Internal Medicine, University Hospitals of Geneva and University of Geneva School of Medicine, Geneva, Switzerland
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146
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Abstract
Toll-like receptors (TLRs) are a family of pattern recognition receptors that are best-known for their role in host defence from infection. Emerging evidence also suggests that TLRs have an important role in maintaining tissue homeostasis by regulating the inflammatory and tissue repair responses to injury. The development of cancer has been associated with microbial infection, injury, inflammation and tissue repair. Here we discuss how the function of TLRs may relate to these processes in the context of carcinogenesis.
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Affiliation(s)
- Seth Rakoff-Nahoum
- Howard Hughes Medical Institute and Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
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147
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Ng G, Sharma K, Ward SM, Desrosiers MD, Stephens LA, Schoel WM, Li T, Lowell CA, Ling CC, Amrein MW, Shi Y. Receptor-independent, direct membrane binding leads to cell-surface lipid sorting and Syk kinase activation in dendritic cells. Immunity 2008; 29:807-18. [PMID: 18993083 DOI: 10.1016/j.immuni.2008.09.013] [Citation(s) in RCA: 218] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2008] [Revised: 07/14/2008] [Accepted: 09/23/2008] [Indexed: 11/30/2022]
Abstract
Binding of particulate antigens by antigen-presenting cells is a critical step in immune activation. Previously, we demonstrated that uric acid crystals are potent adjuvants, initiating a robust adaptive immune response. However, the mechanisms of activation are unknown. By using atomic force microscopy as a tool for real-time single-cell activation analysis, we report that uric acid crystals could directly engage cellular membranes, particularly the cholesterol components, with a force substantially stronger than protein-based cellular contacts. Binding of particulate substances activated Syk kinase-dependent signaling in dendritic cells. These observations suggest a mechanism whereby immune cell activation can be triggered by solid structures via membrane lipid alteration without the requirement for specific cell-surface receptors, and a testable hypothesis for crystal-associated arthropathies, inflammation, and adjuvanticity.
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Affiliation(s)
- Gilbert Ng
- Department of Microbiology and Infectious Diseases, Immunology Research Group, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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148
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Rakoff-Nahoum S, Medzhitov R. Role of toll-like receptors in tissue repair and tumorigenesis. BIOCHEMISTRY (MOSCOW) 2008; 73:555-61. [PMID: 18605980 DOI: 10.1134/s0006297908050088] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Toll-like receptors (TLRs) play a critical role in host defense from microbial infection. TLRs recognize conserved molecular structures produced by microorganisms and induce activation of innate and adaptive immune responses. The inflammatory responses induced by TLRs play an important role TLRs not only in host defense from infection, but also in tissue repair and regeneration. This latter function of TLRs can also contribute to tumorigenesis. Here we review recent progress in understanding the role of TLRs in cancer development.
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Affiliation(s)
- S Rakoff-Nahoum
- Howard Hughes Memorial Institute and Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06510, USA
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149
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Pardo M, Budick-Harmelin N, Tirosh B, Tirosh O. Antioxidant defense in hepatic ischemia-reperfusion injury is regulated by damage-associated molecular pattern signal molecules. Free Radic Biol Med 2008; 45:1073-83. [PMID: 18675899 DOI: 10.1016/j.freeradbiomed.2008.06.029] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Revised: 06/12/2008] [Accepted: 06/25/2008] [Indexed: 12/22/2022]
Abstract
Hepatic ischemia-reperfusion (I/R) injury occurs in a variety of clinical settings and generates the release of endogenous noninfectious ligands called damage-associated molecular pattern (DAMP) signal molecules from damaged cells. This study investigates the effect of DAMP molecules released by Kupffer cells (KC) in I/R injury on the expression of liver manganese superoxide dismutase (MnSOD), a key mitochondrial antioxidant enzyme. We show that MnSOD expression levels are increased in rats and remain high for 24 h after 30 min of ischemia. KC were damaged and depleted after I/R, in association with MnSOD upregulation. Causality was established by treatment with gadolinium chloride, known to selectively destroy KC, which also increased MnSOD levels. Recovery from the early damage (6 h) to the liver tissue was evidenced after 24 h. A physiological protective role for MnSOD was also confirmed by the increased susceptibility of MnSOD-knockdown AML-12 hepatocyte cells to I/R-induced cell death. Inhibition of DAMP molecule high-mobility group box-1 activity by injection of neutralizing antibody partially abolished the increase in liver MnSOD after I/R. Direct injection of ATP, to animals or cells, stimulated MnSOD upregulation. Another DAMP molecule, monosodium urate, also induced MnSOD expression in hepatocyte AML-12 and FaO cell cultures. In conclusion, a connection between danger signals and upregulation of the antioxidant defense system is shown here for the first time in the context of I/R liver injury.
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Affiliation(s)
- Michal Pardo
- Institute of Biochemistry, Food Science, and Nutrition, Faculty of Agricultural, Food, and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
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150
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Beck C, Morbach H, Richl P, Stenzel M, Girschick HJ. How can calcium pyrophosphate crystals induce inflammation in hypophosphatasia or chronic inflammatory joint diseases? Rheumatol Int 2008; 29:229-38. [PMID: 18821074 DOI: 10.1007/s00296-008-0710-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 09/07/2008] [Indexed: 02/08/2023]
Abstract
Hypophosphatasia (HP) is a rare inborn error of bone and mineral metabolism characterized by a defect in the tissue non-specific alkaline phosphatase (TNSALP) gene. Calcium pyrophosphate dihydrate (CPPD) crystals are known to accumulate as substrates of TNSALP in tissues and joints of patients with HP. In CPPD-induced arthritis these crystals are known to induce an inflammatory response. HP patients do suffer from pain in their lower extremities. However, it is not clear whether CPPD crystals contribute to these musculoskeletal complaints in HP. As long as there is no curative treatment of HP, symptomatic treatment in order to improve clinical features, especially with regard to pain and physical activity, is of major interest to the patients. Knowledge of the mechanisms underlying crystal-induced cell activation, however, is limited. Here we describe recent advances in elucidating the signal transduction pathways activated by CPPD crystals as endogenous "danger signals". Recent investigations provided evidence that Toll/interleukin-1 receptor (TIR) domain containing receptors including Toll-like receptors (TLRs) and interleukin-1 receptor (IL-1R), as well as the triggering receptor expressed on myeloid cells 1 (TREM-1) and the NACHT-leucin rich repeat and pyrin-domain-containing protein (NALP3) containing inflammasome are essentially involved in acute CPPD crystal-induced inflammation. These receptors are considered in part as components of the innate immune system. Further studies are needed to improve our understanding of the pathophysiological mechanisms leading to inflammation and tissue destruction associated with deposition of microcrystals. They might support the development of new therapeutic strategies for crystal-induced inflammation. Eventually, patients with HP might as well profit from such strategies addressing these metabolic disorders secondary to the gene defect.
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Affiliation(s)
- C Beck
- Children's hospital, Section of Pediatric Rheumatology, Immunology and Infectious Diseases, University of Würzburg, Josef-Schneider-Str. 2, 97090, Würzburg, Germany.
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