| 11. |
- Deshmukh, Megshree, et al.
(författare)
-
Gene expression of S100a8/a9 predicts Staphylococcus aureus-induced septic arthritis in mice.
- 2023
-
Ingår i: Frontiers in microbiology. - 1664-302X. ; 14
-
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.
|
|
| 12. |
- Elmwall, Jonas, et al.
(författare)
-
Galectin-3 Is a Target for Proteases Involved in the Virulence of Staphylococcus aureus
- 2017
-
Ingår i: Infection and Immunity. - : American Society for Microbiology. - 0019-9567 .- 1098-5522. ; 85:7
-
Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus aureus is a major cause of skin and soft tissue infection. The bacterium expresses four major proteases that are emerging as virulence factors: aureolysin (Aur), V8 protease (SspA), staphopain A (ScpA), and staphopain B (SspB). We hypothesized that human galectin-3, a beta-galactoside-binding lectin involved in immune regulation and antimicrobial defense, is a target for these proteases and that proteolysis of galectin-3 is a novel immune evasion mechanism. Indeed, supernatants from laboratory strains and clinical isolates of S. aureus caused galectin-3 degradation. Similar proteolytic capacities were found in Staphylococcus epidermidis isolates but not in Staphylococcus saprophyticus. Galectin-3-induced activation of the neutrophil NADPH oxidase was abrogated by bacterium-derived proteolysis of galectin-3, and SspB was identified as the major protease responsible. The impact of galectin-3 and protease expression on S. aureus virulence was studied in a murine skin infection model. In galectin-3 (+)/(+) mice, SspB-expressing S. aureus caused larger lesions and resulted in higher bacterial loads than protease-lacking bacteria. No such difference in bacterial load or lesion size was detected in galectin-3 (+)/(+) mice, which overall showed smaller lesion sizes than the galectin-3 (+)/(+) animals. In conclusion, the staphylococcal protease SspB inactivates galectin-3, abrogating its stimulation of oxygen radical production in human neutrophils and increasing tissue damage during skin infection.
|
|
| 13. |
- Fatima, Farah, et al.
(författare)
-
Radiological features of experimental staphylococcal septic arthritis by micro computed tomography scan.
- 2017
-
Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 12:2
-
Tidskriftsartikel (refereegranskat)abstract
- Permanent joint dysfunction due to bone destruction occurs in up to 50% of patients with septic arthritis. Recently, imaging technologies such as micro computed tomography (μCT) scan have been widely used for preclinical models of autoimmune joint disorders. However, the radiological features of septic arthritis in mice are still largely unknown.NMRI mice were intravenously or intra-articularly inoculated with S. aureus Newman or LS-1 strain. The radiological and clinical signs of septic arthritis were followed for 10 days using μCT. We assessed the correlations between joint radiological changes and clinical signs, histological changes, and serum levels of cytokines.On days 5-7 after intravenous infection, bone destruction verified by μCT became evident in most of the infected joints. Radiological signs of bone destruction were dependent on the bacterial dose. The site most commonly affected by septic arthritis was the distal femur in knees. The bone destruction detected by μCT was positively correlated with histological changes in both local and hematogenous septic arthritis. The serum levels of IL-6 were significantly correlated with the severity of joint destruction.μCT is a sensitive method for monitoring disease progression and determining the severity of bone destruction in a mouse model of septic arthritis. IL-6 may be used as a biomarker for bone destruction in septic arthritis.
|
|
| 14. |
- Fei, Ying, et al.
(författare)
-
Commensal Bacteria Augment Staphylococcus aureus septic Arthritis in a Dose-Dependent Manner.
- 2022
-
Ingår i: Frontiers in cellular and infection microbiology. - : Frontiers Media SA. - 2235-2988. ; 12
-
Tidskriftsartikel (refereegranskat)abstract
- Septic arthritis is considered one of the most dangerous joints diseases and is mainly caused by the Gram-positive bacterium Staphylococcus aureus (S. aureus). Human skin commensals are known to augment S. aureus infections. The aim of this study was to investigate if human commensals could augment S. aureus-induced septic arthritis.NMRI mice were inoculated with S. aureus alone or with a mixture of S. aureus together with either of the human commensal Staphylococcus epidermidis (S. epidermidis) or Streptococcus mitis (S. mitis). The clinical, radiological and histopathological changes due to septic arthritis were observed. Furthermore, the serum levels of chemokines and cytokines were assessed.Mice inoculated with a mixture of S. aureus and S. epidermidis or S. mitis developed more severe and frequent clinical arthritis compared to mice inoculated with S. aureus alone. This finding was verified pathologically and radiologically. Furthermore, the ability of mice to clear invading bacteria in the joints but not in kidneys was hampered by the bacterial mixture compared to S. aureus alone. Serum levels of monocyte chemoattractant protein 1 were elevated at the early phase of disease in the mice infected with bacterial mixture compared with ones infected with S. aureus alone. Finally, the augmentation effect in septic arthritis development by S. epidermidis was bacterial dose-dependent.The commensal bacteria dose-dependently augment S. aureus-induced septic arthritis in a mouse model of septic arthritis.
|
|
| 15. |
- Fei, Ying, et al.
(författare)
-
The combination of a tumor necrosis factor inhibitor and antibiotic alleviates staphylococcal arthritis and sepsis in mice.
- 2011
-
Ingår i: The Journal of infectious diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 204:3, s. 348-57
-
Tidskriftsartikel (refereegranskat)abstract
- (See the editorial commentary by Chow, on pages 332-4) Background.Despite advances in medical practices, in recent decades permanent reductions in joint function have not been achieved, and the high mortality rate of patients with staphylococcal septic arthritis has not substantially improved. Methods.We evaluated the effects of a combined tumor necrosis factor (TNF) inhibitor and antibiotic therapy on the course of Staphylococcus aureus arthritis and sepsis in mice. Results.Treatment with the combination of a TNF inhibitor and an antibiotic resulted in a quicker relief of clinical arthritis in mice with septic arthritis, compared with an antibiotic monotherapy. Both histopathologically verified synovitis and the extent of joint destruction were reduced by this combined treatment. Importantly, anti-TNF treatment significantly improved the survival rate of mice with S. aureus sepsis and staphylococcal enterotoxin shock syndrome; this effect might be the result of a partial restoration of the hemostatic balance between coagulation and fibrinolysis. Finally, we demonstrated that anti-TNF treatment downregulates high-mobility group protein B1 in staphylococcal enterotoxin shock syndrome. Conclusions.Thus, simultaneous systemic TNF inhibition and antibiotic therapy has beneficial effects on the outcome of S. aureus arthritis and sepsis in a mouse model, suggesting that the combination of a TNF inhibitor and antibiotics represents a novel therapeutic strategy for the treatment of staphylococcal infections.
|
|
| 16. |
- Gillett, Alan, et al.
(författare)
-
TNF production in macrophages is genetically determined and regulates inflammatory disease in rats.
- 2010
-
Ingår i: Journal of immunology (Baltimore, Md. : 1950). - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 185:1, s. 442-50
-
Tidskriftsartikel (refereegranskat)abstract
- Dysregulation of TNF is an important pathophysiological phenotype for many diseases. Recently, certain genetically regulated loci have been identified to regulate several inflammatory diseases. We hypothesized that a region on rat chromosome 4 known to regulate experimental autoimmune encephalomyelitis, experimental arthritis and experimental autoimmune neuritis harbors a gene regulating central inflammatory molecules, such as TNF. We therefore mapped TNF production using linkage analysis in the 12th generation of an advanced intercross line between DA and PVG.AV1 rats, which differ in susceptibility to several inflammatory conditions. A single TNF-regulating quantitative trait locus with a logarithm of odds score of 6.2 was identified and its biological effect was confirmed in a congenic rat strain. The profound TNF regulation mapped in congenic strains to the macrophage population. Several TLR signaling cascades led to the same reduced proinflammatory phenotype in congenic macrophages, indicating control of a convergence point for innate inflammatory activity. The decreased TNF potential and reduced proinflammatory macrophage phenotype in congenic rats was also associated with reduced clinical severity in experimental autoimmune encephalomyelitis, pristane-induced arthritis and sepsis experimental models. Determination of genes and mechanisms involved in this genetically determined TNF regulation will be valuable in understanding disease pathogenesis and aid treatment development.
|
|
| 17. |
- Gupta, Priti, et al.
(författare)
-
Local Immune Activation and Age Impact on Humoral Immunity in Mice, with a Focus on IgG Sialylation.
- 2024
-
Ingår i: Vaccines. - 2076-393X. ; 12:5
-
Tidskriftsartikel (refereegranskat)abstract
- Age alters the host's susceptibility to immune induction. Humoral immunity with circulating antibodies, particularly immunoglobulin G (IgG), plays an essential role in immune response. IgG glycosylation in the fragment crystallizable (Fc) region, including sialylation, is important in regulating the effector function by interacting with Fc gamma receptors (FcγRs). Glycosylation is fundamentally changed with age and inflammatory responses. We aimed to explore the regulation of humoral immunity by comparing responses to antigen-induced immune challenges in young and adult mice using a local antigen-induced arthritis mouse model. This study examines the differences in immune response between healthy and immune-challenged states across these groups. Our initial assessment of the arthritis model indicated that adult mice presented more severe knee swelling than their younger counterparts. In contrast, we found that neither histological assessment, bone mineral density, nor the number of osteoclasts differs. Our data revealed an age-associated but not immune challenge increase in total IgG; the only subtype affected by immune challenge was IgG1 and partially IgG3. Interestingly, the sialylation of IgG2b and IgG3 is affected by age and immune challenges but not stimulated further by immune challenges in adult mice. This suggests a shift in IgG towards a pro-inflammatory and potentially pathogenic state with age and inflammation.
|
|
| 18. |
- Gupta, Priti, et al.
(författare)
-
The impact of TLR2 and aging on the humoral immune response to Staphylococcus aureus bacteremia in mice.
- 2023
-
Ingår i: Scientific reports. - 2045-2322. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- Aging alters immunoglobulin production, affecting the humoral immune response. Toll-like receptor 2 (TLR2) recognizes Staphylococcus aureus (S. aureus) which causes bacteremia with high mortality in the elderly. To understand how TLR2 and aging affect the humoral immune response in bacteremia, four groups of mice (wild type-young, wild type-old, TLR2-/--young, and TLR2-/--old) were used to analyze immunoglobulin levels in healthy conditions as well as 10days after intravenous injection with S. aureus. We found that aging increased the levels of both IgM and IgG. Increased IgG in aged mice was controlled by TLR2. In bacteremia infection, aged mice failed to mount proper IgM response in both wild-type (WT) and TLR2-/- mice, whereas IgG response was impaired in both aged and TLR2-/- mice. Aged mice displayed reduced IgG1 and IgG2a response irrespective of TLR2 expression. However, impaired IgG2b response was only found in agedWT mice and not in TLR2-/- mice. Both aging and TLR2-/- increased the levels of anti-staphylococcal IgM in bacteremia. Aging increased sialylated IgG in WT mice but not in TLR2-/- mice. IgG sialylation was not affected by the infection in neither of the mice. In summary, aging increases all immunoglobulins except IgG1. However, aged mice fail to mount a proper antibody response to S. aureus bacteremia. TLR2 plays the regulatory role in IgG but not IgM response to infection.
|
|
| 19. |
- Hanna, Balsam, et al.
(författare)
-
Osteopenia/osteoporosis develops in the early phase of disease in patients with idiopathic inflammatory myopathies
- 2021
-
Ingår i: Scandinavian Journal of Rheumatology. - : Informa UK Limited. - 0300-9742 .- 1502-7732. ; 50:5, s. 398-401
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To study the relationship between different disease-related variables and bone mineral density (BMD) in patients with idiopathic inflammatory myopathies (IIMs). Method: Demographic and clinical data were retrospectively collected from the medical records of all patients diagnosed with IIMs during 2003-2018 in the Rheumatology Department, Sahlgrenska University Hospital, Gothenburg, Sweden. BMD measurements by dual-energy X-ray absorptiometry (DXA) were compared among three patient groups categorized according to the time when DXA was performed in relation to the diagnosis: during the first month, 2-6 months, and 7-24 months after diagnosis. Results: In total, 48 patients were included in the study. BMD correlated positively with body mass index and the presence of myositis-specific autoantibodies. As expected, age and diseases duration had negative associations with BMD. Importantly, osteopenia and osteoporosis were significantly more common in patients who underwent DXA at later time-points of the disease than in those who underwent DXA during the first month after diagnosis. Conclusions: Reduced BMD is common in patients with IIMs. The development of osteopenia/osteoporosis starts in the early phase of myositis (within 6 months), and immediate osteoporosis prophylaxis at diagnosis is necessary.
|
|
| 20. |
- Hu, Zhicheng, et al.
(författare)
-
Phenol-soluble modulin α and β display divergent roles in mice with staphylococcal septic arthritis.
- 2022
-
Ingår i: Communications biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 5:1
-
Tidskriftsartikel (refereegranskat)abstract
- Phenol-soluble modulin α (PSMα) is identified as potent virulence factors in Staphylococcus aureus (S. aureus) infections. Very little is known about the role of PSMβ which belongs to the same toxin family. Here we compared the role of PSMs in S. aureus-induced septic arthritis in a murine model using three isogenic S. aureus strains differing in the expression of PSMs (Newman, Δpsmα, and Δpsmβ). The effects of PSMs on neutrophil NADPH-oxidase activity were determined in vitro. We show that the PSMα activates neutrophils via the formyl peptide receptor (FPR) 2 and reduces their NADPH-oxidase activity in response to the phorbol ester PMA. Despite being a poor neutrophil activator, PSMβ has the ability to reduce the neutrophil activating effect of PSMα and to partly reverse the effect of PSMα on the neutrophil response to PMA. Mice infected with S. aureus lacking PSMα had better weight development and lower bacterial burden in the kidneys compared to mice infected with the parental strain, whereas mice infected with bacteria lacking PSMβ strain developed more severe septic arthritis accompanied with higher IL-6 and KC. We conclude that PSMα and PSMβ play distinct roles in septic arthritis: PSMα aggravates systemic infection, whereas PSMβ protects arthritis development.
|
|
