| 1. |
- Carroll, R. K., et al.
(author)
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Identification of an intracellular M17 family leucine aminopeptidase that is required for virulence in Staphylococcus aureus
- 2012
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In: Microbes and Infection. - : Elsevier BV. - 1286-4579. ; 14:11, s. 989-999
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Journal article (peer-reviewed)abstract
- Staphylococcus aureus is a highly virulent bacterial pathogen capable of causing a variety of ailments throughout the human body. It is a major public health concern due to the continued emergence of highly pathogenic methicillin resistant strains (MRSA) both within hospitals and in the community. Virulence in S. aureus is mediated by an array of secreted and cell wall associated virulence factors, including toxins, hemolysins and proteases. In this work we identify a (l) under bar eucine (a) under bar mino (p) under bar eptidase (LAP, pepZ) that strongly impacts the pathogenic abilities of S. aureus. Disruption of the pepZ gene in either Newman or USA300 resulted in a dramatic attenuation of virulence in both localized and systemic models of infection. LAP is required for survival inside human macrophages and gene expression analysis shows that pepZ expression is highest in the intracellular environment. We examine the cellular location of LAP and demonstrate that it is localized to the bacterial cytosol. These results identify for the first time an intracellular leucine aminopeptidase that influences disease causation in a Gram-positive bacterium. (C) 2012 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.
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| 2. |
- Tarkowski, E, et al.
(author)
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Cerebral pattern of pro- and anti-inflammatory cytokines in dementias
- 2003
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In: Brain Research Bulletin. - 0361-9230. ; 61:3, s. 255-260
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Journal article (peer-reviewed)abstract
- The knowledge regarding putative inflammatory component(s) participating in Alzheimer's disease (AD) and vascular dementia (VAD) is scarce. Recently, we have demonstrated the presence of certain inflammatory cytokines in the cerebrospinal fluid (CSF) of demented patients. Although the initial event(s) triggering the neurodegenerative processes in AD versus VAD may be different and lead to different neuropathological changes, it may initiate a similar cascade of cytokine production in response to neuronal injury. The cytokines released in the central nervous system (CNS) may, in turn, act in a similar manner in both diseases, amplifying some pathological changes such as amyloidogenesis and white matter lesions or on the contrary acting as neuroprotective molecules. This review will focus on the intracerebral production of the pro- and anti-inflammatory cytokines interleukin IL-1beta, IL-1 receptor antagonist (IL-1ra), IL-6 and TNF-alpha in dementia, and their relation to gene polymorphism, to cerebral neuronal damage, apoptosis, and to clinical variables of dementia. Our results, which show for the first time strikingly increased CSF levels of TNF-alpha but not of TNF-beta, IL-1beta or IL-6 in AD and VAD, may form a conceptual framework for further studies of neuroprotective mechanisms in dementias. (C) 2003 Elsevier Science Inc. All rights reserved.
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| 3. |
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| 4. |
- Baran, M, et al.
(author)
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SURVIVIN IS AN ESSENTIAL MEDIATOR OF ARTHRITIS INTERACTING WITH UROKINASE SIGNALLING.
- 2009
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In: Journal of cellular and molecular medicine. - : Wiley. - 1582-4934 .- 1582-1838. ; 13:9B, s. 3797-3808
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Journal article (peer-reviewed)abstract
- ABSTRACT Proto-oncogene survivin has recently been identified as a prognostic marker distinguishing patients with destructive rheumatoid arthritis (RA). In the present material of 132 RA patients and 82 controls the levels of survivin correlated to urokinase (uPA) (r=0.46), a plasminogen activator over expressed in inflamed joints and known to exhibit potent arthritogenic properties. Here we evaluate the functional relationship between these proteins using primary synovial fibroblasts and leukocytes of RA patients, human monocytic (THP-1) and fibroblast (MRC-5) cell lines. Using inhibitors of intracellular signalling we show that uPA and survivin share common transduction pathways being in synovial fibroblasts dependent on the activity of tyrosine kinases, PI3-kinase and MEK. Moreover, uPA production is significantly reduced in fibroblasts if survivin synthesis has been silenced by siRNA. Importantly, silencing of survivin in fibroblasts prevented their invasive growth in knee joints of SCID mice. Interaction of uPA with receptor up regulates survivin expression in leukocytes. In turn, survivin is required for the upregulation of uPA receptor on cell surface. These findings indicate that survivin is an essential mediator of arthritogenic properties of uPA regulating its synthesis in synovial fibroblasts and uPAR expression in leukocytes. Close correlation between survivin and uPA levels in patients with RA supports the importance of this connection for the pathogenesis of arthritis.
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| 5. |
- Bergquist, Jonas, et al.
(author)
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Measurements of catecholamine-mediated apoptosis of immunocompetent cells by capillary electrophoresis.
- 1997
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In: Electrophoresis. - : Wiley. - 0173-0835 .- 1522-2683. ; 18:10, s. 1760-6
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Journal article (peer-reviewed)abstract
- Single cell analysis with capillary electrophoresis, a technique capable of detecting zeptomole quantities (10(-21) mole) of neurochemical species, has been used to demonstrate that lymphocytes are capable of active synthesis of dopamine and norepinephrine. Exposure of lymphocytes to catecholamines at concentrations as low as 10 nM leads to decreased proliferation and differentiation, e.g. interferon-gamma (IFN-gamma), interleukin-4 (IL-4) and immunoglobulin (Ig). In addition, both inhibition of dopamine uptake with nomifensine and inhibition of packing of catecholamines into vesicles with tetrabenazine, results in significantly lower levels of dopamine and norepinephrine (p < 0.01 and p < 0.05, respectively). The catecholamine-dependent inhibition of T- and B-lymphocyte activity is mediated via an induction of a Bcl-2/Bax and Fas/FasL involved apoptosis. These findings indicate a novel mechanism for regulation of lymphocyte activity in the central nervous system, whereby elevated regional levels of catecholamines might lead to the immunoprivilege of the brain.
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| 6. |
- Bjersing, Jan, 1966, et al.
(author)
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Impact of site-specific nucleobase deletions on the arthritogenicity of DNA
- 2004
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In: Inflammation. - 0360-3997. ; 28:3, s. 159-68
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Journal article (peer-reviewed)abstract
- Oligodeoxynucleotides (ODN) containing unmethylated CpG motifs (CpG ODN) potently stimulate the innate and acquired immune system. We have compared the in vivo and in vitro inflammatogenic properties of CpG ODNs containing a specific nucleobase deletion either 5'-upstream (ODN-2) or 3'-downstream (ODN-3) of the CpG motif, comparing with a prototype CpG ODN (ODN-1). The frequency of arthritis was similar after intra-articular (i.a.) injections of ODN-1 or ODN-3, but was significantly lower (p < 0.02) after i.a. injections of ODN-2. In vitro production of the pro-inflammatory cytokine TNF-alpha was higher in mouse spleen cell cultures exposed to ODN-2 in comparison to ODN-1. In addition, the level of IL-10 induced by ODN-2 was higher than that induced by ODN-1. On the other hand, TNF-alpha, IL-10, and MCP-1 levels, as well as splenocyte proliferative responses were all significantly lower for ODN-3 than for ODN-1. These results suggest that a 5'-upstream nucleobase deletion reduces arthritogenicity, while maintaining or increasing the production of pro- and anti-inflammatory factors. In contrast, a 3'-downstream nucleobase deletion has no effect on arthritogenicity, despite significantly lower levels of proliferation and pro- and anti-inflammatory cytokines, compared with ODN-1. This study indicates that specific structural elements within the ODN sequence but outside the CpG motif, modulate the immunostimulatory properties of CpG ODNs.
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| 7. |
- Brittberg, Mats, 1953, et al.
(author)
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Clonal growth of human articular cartilage and the functional role of the periosteum in chondrogenesis.
- 2005
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In: Osteoarthritis and cartilage / OARS, Osteoarthritis Research Society. - : Elsevier BV. - 1063-4584. ; 13:2, s. 146-53
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Journal article (peer-reviewed)abstract
- OBJECTIVE: Clinical cartilage repair with transplantation of cultured chondrocytes, the first described technique introduced in 1994, includes a periosteal membrane but today cells are also implanted without the periosteal combination. The aim of this study was to see if the periosteum had more than a biomechanical function and if the periosteum had a biological effect on the seeded cells tested in an agarose system in which the clonal growth in agarose and the external growth stimulation could be analysed. METHODS: Four different experiments were used to study the growth of human chondrocytes in agarose and the periosteal influence. Human chondrocytes were isolated and transferred to either primary or secondary agarose culture. After 4 weeks, the total number of clones >50 microm was counted. Cocultures of chondrocytes and periosteal tissue, cultures of chondrocytes with conditioned medium from chondrocytes, periosteal cells and fibroblast were used to study a potential stimulatory effect on growth and different cytokines and growth factors were analysed. RESULTS: It was found that the human chondrocytes had different growth properties in agarose with the formation of four different types of clones: a homogenous clone without matrix production, a homogenous clone with matrix production, a differentiated clone with matrix production and finally a differentiated clone without matrix production. The periosteum exerted a paracrine effect on cultured chondrocytes in agarose resulting in a higher degree of cloning. The chondrocytes produced significant amounts of interleukin (IL)-6, IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF) and transforming growth factor (TGF)-beta. The periosteum produced significant amounts of IL-6, IL-8 and TGF-beta. Cocultures of chondrocytes and periosteum demonstrated a potentiation of IL-6 and IL-8 release but not of TGF-beta and GM-CSF. CONCLUSION: Articular chondrocytes are able to form clones of different properties in agarose and the periosteum has a capacity of stimulating chondrocyte clonal growth and differentiation and secretes significant amounts of IL-6, IL-8, GM-CSF and TGF-beta. It may be that the repair of cartilage defects with seeded chondrocytes could benefit from the combination with a periosteal graft. The production of TGF-beta by implanted chondrocytes could influence the chondrogenic cells in the periosteum to start a periosteal chondrogenesis and together with the matrix from implanted chondrocyte production, a repair of cartilaginous appearance may develop; a dual chondrogenic response is possible.
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| 8. |
- Collins, Vincent, 1962, et al.
(author)
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Endogenously oxidized mitochondrial DNA induces in vivo and in vitro inflammatory responses
- 2004
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In: J Leukoc Biol. - : Oxford University Press (OUP). - 0741-5400. ; 75:6, s. 995-1000
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Journal article (peer-reviewed)abstract
- We report that mitochondrial DNA (mtDNA) is inflammatogenic in vitro and in vivo as a result of the presence of unmethylated CpG sequences and its oxidative status. Purified human and murine mtDNAs induced arthritis when injected intra-articularly (i.a.) in mice. Importantly, oligodeoxynucleotide that contained a single oxidatively damaged base also induced arthritis when injected i.a. in mice. In contrast, neither human nor murine nuclear DNA induced inflammation. mtDNA-induced arthritis was neither B cell- nor T cell-dependent but was mediated by monocytes/macrophages. mtDNA-induced nuclear factor-kappaB stimulation resulted in the production of tumor necrosis factor alpha, a potent, arthritogenic factor. Finally, extracellular mtDNA was detected in the synovial fluids of rheumatoid arthritis patients but not of control subjects. We conclude that endogenous mtDNA displays inflammatogenic properties as a result of its content of unmethylated CpG motifs and oxidatively damaged adducts.
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| 9. |
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| 10. |
- Dehlin, Mats, 1968, et al.
(author)
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Intra-articular fms-like tyrosine kinase 3 ligand expression is a driving force in induction and progression of arthritis.
- 2008
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:11
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Journal article (peer-reviewed)abstract
- BACKGROUND: One of the hallmarks of rheumatoid arthritis (RA) is hyperplasia and inflammation of the synovial tissue being characterized by in situ occurrence of highly differentiated leukocytes. Fms-like tyrosine kinase 3 (Flt3) has a crucial role in hematopoiesis, regulation of cell proliferation, differentiation and apoptosis. Typically, Flt3 is expressed on early myeloid and lymphoid progenitors and is activated by its soluble ligand (Flt3-L). The highly differentiated cellular pattern in the synovium of the RA patients made us hypothesize that Flt3-L, with its ability to induce proliferation and differentiation, could be of importance in induction and/or progression of arthritis. METHODOLOGY/PRINCIPAL FINDINGS: To investigate occurrence of Flt3-L in RA we have measured its levels in matched serum and synovial fluid samples from 130 patients and 107 controls. To analyse the pro-inflammatory role of Flt3-L, we continuously overexpressed this protein locally in healthy mouse joints using homologous B-cell line transfected with Flt3-L gene. Additionally, recombinant Flt3-L was instillated intra-articularly in combination with peptidoglycans, a Toll Like Receptor 2-ligand with stong arthritogenic properties. Our results show significantly higher levels of Flt3-L in the synovial fluid as compared to serum levels in RA subjects (p = 0.0001). In addition, RA synovial fluid levels of Flt-3-L were significantly higher than these obtained from synovial fluids originating from non-inflammatory joint diseases (p = 0.022). Intra-articular administration of B-cell line transfected with Flt3-L gene resulted in highly erosive arthritis while inoculation of the same B-cell line without hyperexpression of Flt3-L did not induce erosivity and only in a minority of cases caused synovial proliferation! Flt3-ligand potentiated peptidoglycan induced arthritis as compared to mice injected with peptidoglycan alone (p<0.05). CONCLUSIONS/SIGNIFICANCE: Our findings indicate that Flt3-L is strongly expressed at the site of inflammation in human RA. It exerts both pro-inflammatory and tissue destructive properties once in the joint cavity. Owing to these properties, treatment attempts to neutralize this molecule should be considered in RA.
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