| 1. |
- 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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| 2. |
- Hu, Zhicheng, et al.
(författare)
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Phenol-soluble modulin α and β display divergent roles in mice with staphylococcal septic arthritis.
- 2022
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Ingår i: Communications biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 5:1
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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.
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| 3. |
- Krzyzowska, Malgorzata, et al.
(författare)
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Tofacitinib treatment in primary herpes simplex encephalitis interferes with anti-viral response.
- 2022
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Ingår i: The Journal of infectious diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 225:9, s. 1545-1553
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Tidskriftsartikel (refereegranskat)abstract
- Tofacitinib, a Janus kinase inhibitor, is a novel immunosuppressive drug for treatment of rheumatoid arthritis (RA). Herpes simplex virus type 1 (HSV-1) may cause encephalitis during primary infection or following reactivation from a latent state. Long-term tofacitinib treatment may increase the risk of this life-threatening condition. The aim of this study was to investigate the effect of tofacitinib on HSV-1 primary infection using a mouse model. Mice pre-treated with tofacitinib were intranasally infected with a clinical strain of HSV-1 and monitored for infection severity and anti-viral response. Tofacitinib treatment of HSV-1 primary infection resulted in increased viral loads and worsened clinical outcome. Furthermore, tofacitinib promoted M2 anti-inflammatory phenotype of microglia and infiltrating monocytes as well as inhibited production of inflammatory and antiviral cytokines by macrophages in vitro. Our findings show that treatment with tofacitinib increases severity of HSE in mice, by impairing anti-viral response induced by monocytes and microglia.
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| 4. |
- Schultz, Michelle, et al.
(författare)
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Lipoproteins Cause Bone Resorption in a Mouse Model of Staphylococcus aureus Septic Arthritis
- 2022
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Septic arthritis, most often caused by Staphylococcus aureus, is a rapidly progressive and destructive joint disease with substantial mortality and morbidity. Staphylococcus aureus lipoproteins (Lpps) are known to induce arthritis and bone destruction. Here, we aimed to investigate the bone resorptive effect of S. aureus Lpps in a murine arthritis model by intra-articular injection of purified S. aureus Lpps, synthetic lipopeptides, and live S. aureus strains. Analyses of the bone mineral density (BMD) of the distal femur bone were performed. Intra-articular injection of both live S. aureus and purified S. aureus Lpps were shown to significantly decrease total- and trabecular BMD. Liquid chromatography-mass spectrometry analyses revealed that the Lpps expressed by S. aureus SA113 strain contain both diacyl and triacyl lipid moieties. Interestingly, synthetic diacylated lipopeptide, Pam(2)CSK(4), was more potent in inducing bone resorption than synthetic triacylated lipopeptide, Pam(3)CSK(4). Modified lipoproteins lacking the lipid moiety were deprived of their bone resorptive abilities. Monocyte depletion by clodronate liposomes fully abrogated the bone resorptive capacity of S. aureus lipoproteins. Our data suggest that S. aureus Lpps induce bone resorption in locally-induced murine arthritis, an effect mediated by their lipid-moiety through monocytes/macrophages.
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