| 1. |
- Hannan, T. J., et al.
(författare)
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Inhibition of cyclooxygenase-2 prevents chronic and recurrent cystitis
- 2014
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Ingår i: EBioMedicine. - : Elsevier. - 2352-3964. ; 1:1, s. 46-57
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Tidskriftsartikel (refereegranskat)abstract
- The spread of multidrug-resistant microorganisms globally has created an urgent need for novel therapeuticstrategies to combat urinary tract infections (UTIs). Immunomodulatory therapy may provide benefit, as treatmentof mice with dexamethasone during acute UTI improved outcome by reducing the development of chroniccystitis, which predisposes to recurrent infection. Herewe discovered soluble biomarkers engaged inmyeloid celldevelopment and chemotaxis that were predictive of future UTI recurrence when elevated in the sera of youngwomen with UTI. Translation of these findings revealed that temperance of the neutrophil response early duringUTI, and specifically disruption of bladder epithelial transmigration of neutrophils by inhibition ofcyclooxygenase-2, protected mice against chronic and recurrent cystitis. Further, proteomics identified bladderepithelial remodeling consequent to chronic infection that enhances sensitivity to neutrophil damage. Thus, cyclooxygenase-2 expression during acute UTI is a critical molecular trigger determining disease outcome anddrugs targeting cyclooxygenase-2 could prevent recurrent UTI.
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| 2. |
- Hickey, C. A., et al.
(författare)
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Colitogenic Bacteroides thetaiotaomicron Antigens Access Host Immune Cells in a Sulfatase-Dependent Manner via Outer Membrane Vesicles
- 2015
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Ingår i: Cell Host & Microbe. - : Elsevier BV. - 1931-3128. ; 17:5, s. 672-680
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Tidskriftsartikel (refereegranskat)abstract
- Microbes interact with the host immune system via several potential mechanisms. One essential step for each mechanismis themethod by which intestinal microbes or their antigens access specific host immune cells. Using genetically susceptible mice (dnKO) that develop spontaneous, fulminant colitis, triggered by Bacteroides thetaiotaomicron (B. theta), we investigated the mechanism of intestinal microbial access under conditions that stimulate colonic inflammation. B. theta antigens localized to host immune cells through outer membrane vesicles (OMVs) that harbor bacterial sulfatase activity. We deleted the anaerobic sulfatase maturating enzyme (anSME) from B. theta, which is required for post-translational activation of all B. theta sulfatase enzymes. This bacterial mutant strain did not stimulate colitis in dnKO mice. Lastly, access of B. theta OMVs to host immune cells was sulfatase dependent. These data demonstrate that bacterial OMVs and associated enzymes promote inflammatoryimmune stimulation in genetically susceptible hosts.
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| 3. |
- Hsieh, Samantha, et al.
(författare)
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Polysaccharide Capsules Equip the Human Symbiont Bacteroides thetaiotaomicron to Modulate Immune Responses to a Dominant Antigen in the Intestine
- 2020
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 204:4, s. 1035-1046
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Tidskriftsartikel (refereegranskat)abstract
- Bacteria express multiple diverse capsular polysaccharides (CPSs) for protection against environmental and host factors, including the host immune system. Using a mouse TCR transgenic CD4+ T cell, BθOM, that is specific for B. thetaiotaomicron and a complete set of single CPS-expressing B. thetaiotaomicron strains, we ask whether CPSs can modify the immune responses to specific bacterial Ags. Acapsular B. thetaiotaomicron, which lacks all B. thetaiotaomicron CPSs, stimulated BθOM T cells more strongly than wild-type B. thetaiotaomicron Despite similar levels of BθOM Ag expression, many single CPS-expressing B. thetaiotaomicron strains were antistimulatory and weakly activated BθOM T cells, but a few strains were prostimulatory and strongly activated BθOM T cells just as well or better than an acapsular strain. B. thetaiotaomicron strains that expressed an antistimulatory CPS blocked Ag delivery to the immune system, which could be rescued by Fc receptor-dependent Ab opsonization. All single CPS-expressing B. thetaiotaomicron strains stimulated the innate immune system to skew toward M1 macrophages and release inflammatory cytokines in an MyD88-dependent manner, with antistimulatory CPS activating the innate immune system in a weaker manner than prostimulatory CPS. The expression of antistimulatory versus prostimulatory CPSs on outer membrane vesicles also regulated immune responses. Moreover, antistimulatory and prostimulatory single CPS-expressing B. thetaiotaomicron strains regulated the activation of Ag-specific and polyclonal T cells as well as clearance of dominant Ag in vivo. These studies establish that the immune responses to specific bacterial Ags can be modulated by a diverse set of CPSs.
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