| 1. |
- Ali, Abukar, 1988, et al.
(författare)
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Antibiotic-killed Staphylococcus aureus induces destructive arthritis in mice.
- 2015
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Ingår i: Arthritis & rheumatology (Hoboken, N.J.). - : Wiley. - 2326-5205 .- 2326-5191. ; 67:1, s. 107-116
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Permanent reduction in joint function is a severe post-infectious complication in patients with Staphylococcus aureus septic arthritis. This reduction in joint function might be caused by persistent joint inflammation after the adequate eradication of bacteria by antibiotics. Methods: We studied whether antibiotic-killed S. aureus induced joint inflammation in mice and elucidated the molecular and cellular mechanism of this type of arthritis. Results: The intraarticular injection of antibiotic-killed S. aureus induced mild to moderate synovitis and bone erosions that lasted for a minimum of 14 days. The frequency and severity of synovitis were significantly reduced in tumor necrosis factor receptor 1 (TNFR1), receptor for Advanced Glycation End Products (RAGE), and toll like receptor 2 (TLR2) knockout mice compared with wild-type animals. The combined depletion of monocytes and neutrophils resulted in a significantly lower frequency of synovitis. Among bacterial factors, insoluble cell debris played a more important role than bacterial DNA or soluble components in inducing joint inflammation. Importantly, anti-TNF therapy abrogated the joint inflammation induced by antibiotic-killed S. aureus. Conclusion: Antibiotic-killed S. aureus induced and maintained the joint inflammation that is mediated through TLR2, TNFR1, and RAGE receptor. The cross-talk between neutrophils and monocytes is responsible for this type of arthritis. Anti-TNF therapy might be used as a novel therapeutic strategy, in combination with antibiotics, to treat staphylococcal septic arthritis. © 2014 American College of Rheumatology.
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| 2. |
- Ali, Abukar, 1988, et al.
(författare)
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CTLA4-Ig but not anti-TNF therapy promotes staphylococcal septic arthritis in mice.
- 2015
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Ingår i: The Journal of infectious diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 212:8, s. 1308-1316
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Tidskriftsartikel (refereegranskat)abstract
- The development of biologics has greatly increased the quality of life as well as the life expectancy of many RA patients. However, a large number of these patients are at an increased risk of developing serious infections. The aim of this study was to examine differential effects of anti-TNF versus CTLA4-Ig treatment on both immunological response and host defense in a murine model of septic arthritis.
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| 3. |
- Ali, Abukar, 1988, et al.
(författare)
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IL-1 Receptor Antagonist Treatment Aggravates Staphylococcal Septic Arthritis and Sepsis in Mice.
- 2015
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- Interleukin-1 receptor antagonist (IL-1Ra) is the primary therapy against autoinflammatory syndromes with robust efficacy in reducing systemic inflammation and associated organ injury. However, patients receiving IL-1Ra might be at increased risk of acquiring serious infections.
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| 4. |
- Ammanath, Aparna Viswanathan, et al.
(författare)
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From an Hsp90 - binding protein to a peptide drug.
- 2022
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Ingår i: microLife. - : Oxford University Press (OUP). - 2633-6693. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- The Lpl proteins represent a class of lipoproteins that was first described in the opportunistic bacterial pathogen Staphylococcus aureus, where they contribute to pathogenicity by enhancing F-actin levels of host epithelial cells and thereby increasing S. aureus internalization. The model Lpl protein, Lpl1 was shown to interact with the human heat shock proteins Hsp90α and Hsp90ß, suggesting that this interaction may trigger all observed activities. Here we synthesized Lpl1-derived peptides of different lengths and identified two overlapping peptides, namely, L13 and L15, which interacted with Hsp90α. Unlike Lpl1, the two peptides not only decreased F-actin levels and S. aureus internalization in epithelial cells but they also decreased phagocytosis by human CD14+ monocytes. The well-known Hsp90 inhibitor, geldanamycin, showed a similar effect. The peptides not only interacted directly with Hsp90α, but also with the mother protein Lpl1. While L15 and L13 significantly decreased lethality of S. aureus bacteremia in an insect model, geldanamycin did not. In a mouse bacteremia model L15 was found to significantly decreased weight loss and lethality. Although the molecular bases of the L15 effect is still elusive, in vitro data indicate that simultaneous treatment of host immune cells with L15 or L13 and S. aureus significantly increase IL-6 production. L15 and L13 represent not antibiotics but they cause a significant reduction in virulence of multidrug-resistant S. aureus strains in in vivo models. In this capacity, they can be an important drug alone or additive with other agents.
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| 5. |
- Baranwal, Gaurav, et al.
(författare)
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Impact of cell wall peptidoglycan O-acetylation on the pathogenesis of Staphylococcus aureus in septic arthritis.
- 2017
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Ingår i: International journal of medical microbiology : IJMM. - : Elsevier BV. - 1618-0607 .- 1438-4221. ; 307:7, s. 388-397
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus aureus (S. aureus) is one of the most common pathogen causing septic arthritis. To colonize the joints and establish septic arthritis this bacterium needs to resist the host innate immune responses. Lysozyme secreted by neutrophils and macrophages is an important defense protein present in the joint synovial fluids. S. aureus is known to be resistant to lysozyme due to its peptidoglycan modification by O-acetylation of N-acetyl muramic acid. In this study we have investigated the role of O-acetylated peptidoglycan in septic arthritis. Using mouse models for both local and hematogenous S. aureus arthritis we compared the onset and progress of the disease induced by O-acetyl transferase mutant and the parenteral wild type SA113 strain. The disease progression was assessed by observing the clinical parameters including body weight, arthritis, and functionality of the affected limbs. Further X-ray and histopathological examinations were performed to monitor the synovitis and bone damage. In local S. aureus arthritis model, mice inoculated with the ΔoatA strain developed milder disease (in terms of knee swelling, motor and movement functionality) compared to mice inoculated with the wild type SA113 strain. X-ray and histopathological data revealed that ΔoatA infected mice knee joints had significantly lesser joint destruction, which was accompanied by reduced bacterial load in knee joints. Similarly, in hematogenous S. aureus arthritis model, ΔoatA mutant strain induced significantly less severe clinical septic arthritis compared to its parental strain, which is in accordance with radiological findings. Our data indicate that peptidoglycan O-acetylation plays an important role in S. aureus mediated septic arthritis.
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| 6. |
- Bergmann, Berglind, et al.
(författare)
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Pre-treatment with IL2 gene therapy alleviates Staphylococcus aureus arthritis in mice.
- 2020
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Ingår i: BMC infectious diseases. - : Springer Science and Business Media LLC. - 1471-2334. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus aureus (S. aureus) arthritis is one of the most detrimental joint diseases known and leads to severe joint destruction within days. We hypothesized that the provision of auxiliary immunoregulation via an expanded compartment of T regulatory cells (Tregs) could dampen detrimental aspects of the host immune response whilst preserving its protective nature. Administration of low-dose interleukin 2 (IL2) preferentially expands Tregs, and is being studied as a treatment choice in several autoimmune conditions. We aimed to evaluate the role of IL2 and Tregs in septic arthritis using a well-established mouse model of haematogenously spred S. aureus arthritis.C57BL/6 or NMRI mice we intravenously (iv) injected with a defined dose of S. aureus LS-1 or Newman and the role of IL2 and Tregs were assessed by the following approaches: IL2 was endogenously delivered by intraperitoneal injection of a recombinant adeno-associated virus vector (rAAV) before iv S. aureus inoculation; Tregs were depleted before and during S. aureus arthritis using antiCD25 antibodies; Tregs were adoptively transferred before induction of S. aureus arthritis and finally, recombinant IL2 was used as a treatment starting day 3 after S. aureus injection. Studied outcomes included survival, weight change, bacterial clearance, and joint damage.Expansion of Tregs induced by IL2 gene therapy prior to disease onset does not compromise host resistance to S. aureus infection, as the increased proportions of Tregs reduced the arthritis severity as well as the systemic inflammatory response, while simultaneously preserving the host's ability to clear the infection.Pre-treatment with IL2 gene therapy dampens detrimental immune responses but preserves appropriate host defense, which alleviates S. aureus septic arthritis in a mouse model.
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| 7. |
- Bokarewa, Maria, 1963, et al.
(författare)
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Intraarticular release and accumulation of defensins and bactericidal/permeability-increasing protein in patients with rheumatoid arthritis.
- 2003
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Ingår i: The Journal of rheumatology. - 0315-162X. ; 30:8, s. 1719-24
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Defensins and bactericidal/permeability-increasing protein (BPI) are the components of the azurophilic granules of polymorphonuclear cells (PMNC) maintaining antimicrobial protection. Both these substances have been suggested to interact with the host immune system rather than merely kill invading pathogens. We assessed concentrations of BPI and a-defensins in synovial fluid (SF) and matching blood samples of patients with rheumatoid arthritis (RA). METHODS: Matching samples of SF and blood were collected from 67 patients with RA (aged 21-73 yrs) with acute joint effusion. Blood samples from 22 healthy individuals made up a control group. Concentrations of BPI and human neutrophil peptides (HNP 1-3) were measured by ELISA. The results were related to radiological signs of destructive arthritis, duration of the disease, and laboratory markers of inflammation. RESULTS: BPI and HNP concentrations in SF were 10-60 times higher than in matching blood samples (p < 0.0001). Strong correlations between BPI and HNP concentrations were found in both blood and SF. In SF, BPI and HNP concentrations correlated to white blood cell (WBC) count (p < 0.001), and were associated with erosive joint disease (p < 0.05). In contrast, WBC count, serum C-reactive protein, or rheumatoid factor were not significantly correlated to the BPI or HNP concentrations. Serum BPI concentrations were moderately but significantly increased in RA patients compared in blood to controls (p < 0.05). CONCLUSION: BPI and HNP are accumulated in the synovial cavity of patients with RA. Significant correlation between joint erosion and local occurrence of BPI and HNP suggests participation of these molecules in regulation of the destructive course of RA.
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| 8. |
- Bokarewa, Maria, 1963, et al.
(författare)
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Staphylococcus aureus: Staphylokinase
- 2006
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Ingår i: Int J Biochem Cell Biol. - 1357-2725. ; 38:4, s. 504-9
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Tidskriftsartikel (refereegranskat)abstract
- Staphylokinase is a 136 aa long bacteriophage encoded protein expressed by lysogenic strains of Staphylococcus aureus. Present understanding of the role of staphylokinase during bacterial infection is based on its interaction with the host proteins, alpha-defensins and plasminogen. alpha-Defensins are bactericidal peptides originating from human neutrophils. Binding of staphylokinase to alpha-defensins abolishes their bactericidal properties, which makes staphylokinase a vital tool for staphylococcal resistance to host innate immunity. Complex binding between staphylokinase and plasminogen results in the formation of active plasmin, a broad-spectrum proteolytic enzyme facilitating bacterial penetration into the surrounding tissues. We have recently shown high levels of staphylokinase expression in clinical isolates of skin and mucosal origin and relative low levels in isolates invading internal organs. These findings are supported by sepsis studies using isogenic S. aureus strains demonstrating increased bacterial load in the absence of staphylokinase production. Our observations indicate that staphylokinase favours symbiosis of staphylococci with the host that makes it an important colonization factor.
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| 9. |
- Boldock, Emma, et al.
(författare)
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Human skin commensals augment Staphylococcus aureus pathogenesis.
- 2018
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Ingår i: Nature microbiology. - : Springer Science and Business Media LLC. - 2058-5276. ; 3:8, s. 881-90
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Tidskriftsartikel (refereegranskat)abstract
- All bacterial infections occur within a polymicrobial environment, from which a pathogen population emerges to establish disease within a host. Emphasis has been placed on prevention of pathogen dominance by competing microflora acting as probiotics1. Here we show that the virulence of the human pathogen Staphylococcus aureus is augmented by native, polymicrobial, commensal skin flora and individual species acting as 'proinfectious agents'. The outcome is pathogen proliferation, but not commensal. Pathogenesis augmentation can be mediated by particulate cell wall peptidoglycan, reducing the S. aureus infectious dose by over 1,000-fold. This phenomenon occurs using a range of S. aureus strains and infection models and is not mediated by established receptor-mediated pathways including Nod1, Nod2, Myd88 and the NLPR3 inflammasome. During mouse sepsis, augmentation depends on liver-resident macrophages (Kupffer cells) that capture and internalize both the pathogen and the proinfectious agent, leading to reduced production of reactive oxygen species, pathogen survival and subsequent multiple liver abscess formation. The augmented infection model more closely resembles the natural situation and establishes the role of resident environmental microflora in the initiation of disease by an invading pathogen. As the human microflora is ubiquitous2, its role in increasing susceptibility to infection by S. aureus highlights potential strategies for disease prevention.
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| 10. |
- Deshmukh, Megshree, et al.
(författare)
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Gene expression of S100a8/a9 predicts Staphylococcus aureus-induced septic arthritis in mice.
- 2023
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Ingår i: Frontiers in microbiology. - 1664-302X. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Septic arthritis is the most aggressive joint disease associated with high morbidity and mortality. The interplay of the host immune system with the invading pathogens impacts the pathophysiology of septic arthritis. Early antibiotic treatment is crucial for a better prognosis to save the patients from severe bone damage and later joint dysfunction. To date, there are no specific predictive biomarkers for septic arthritis. Transcriptome sequencing analysis identified S100a8/a9 genes to be highly expressed in septic arthritis compared to non-septic arthritis at the early course of infection in an Staphylococcus aureus septic arthritis mouse model. Importantly, downregulation of S100a8/a9 mRNA expression at the early course of infection was noticed in mice infected with the S. aureus Sortase A/B mutant strain totally lacking arthritogenic capacity compared with the mice infected with parental S. aureus arthritogenic strain. The mice infected intra-articularly with the S. aureus arthritogenic strain significantly increased S100a8/a9 protein expression levels in joints over time. Intriguingly, the synthetic bacterial lipopeptide Pam2CSK4 was more potent than Pam3CSK4 in inducing S100a8/a9 release upon intra-articular injection of these lipopeptides into the mouse knee joints. Such an effect was dependent on the presence of monocytes/macrophages. In conclusion, S100a8/a9 gene expression may serve as a potential biomarker to predict septic arthritis, enabling the development of more effective treatment strategies.
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