| 1. |
- Barrett, Aidan, et al.
(author)
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Role of estrogen signaling in fibroblastic reticular cells for innate and adaptive immune responses in antigen-induced arthritis
- 2024
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In: IMMUNOLOGY AND CELL BIOLOGY. - 0818-9641 .- 1440-1711.
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Journal article (peer-reviewed)abstract
- Women are more prone to develop rheumatoid arthritis, with peak incidence occurring around menopause. Estrogen has major effects on the immune system and is protective against arthritis. We have previously shown that treatment with estrogen inhibits inflammation and joint destruction in murine models of arthritis, although the mechanisms involved remain unclear. Fibroblastic reticular cells (FRCs) are specialized stromal cells that generate the three-dimensional structure of lymph nodes (LNs). FRCs are vital for coordinating immune responses from within LNs and are characterized by the expression of the chemokine CCL19, which attracts immune cells. The aim of this study was to determine whether the influence of estrogen on innate and adaptive immune cells in arthritis is mediated by estrogen signaling in FRCs. Conditional knockout mice lacking estrogen receptor alpha (ER alpha) in CCL19-expressing cells (Ccl19-CreER alpha fl/fl) were generated and tested. Ccl19-CreER alpha fl/fl mice and littermate controls were ovariectomized, treated with vehicle or estradiol and subjected to the 28-day-long antigen-induced arthritis model to enable analyses of differentiated T- and B-cell populations and innate cells in LNs by flow cytometry. The results reveal that while the response to estradiol treatment in numbers of FRCs per LN is significantly reduced in mice lacking ER alpha in FRCs, estrogen does not inhibit joint inflammation or markedly affect immune responses in this arthritis model. Thus, this study validates the Ccl19-CreER alpha fl/fl strain for studying estrogen signaling in FRCs within inflammatory diseases, although the chosen arthritis model is deemed unsuitable for addressing this question. This study investigated the influence of signaling through estrogen receptor alpha (ER alpha) in fibroblastic reticular cells (FRCs) on innate and adaptive immune responses using a mouse model where ER alpha was conditionally deleted in CCL19-expressing cells. The results reveal that the deletion of ER alpha in FRCs does not affect the FRC phenotype or LN architecture at steady state while the response of FRCs to estrogen treatment during experimental arthritis is significantly reduced in the conditional knock-out mice. However, ER alpha signaling via FRCs does not inhibit joint inflammation or markedly affect immune responses in the antigen-induced arthritis model. image
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| 2. |
- Drevinge, Christina, 1983, et al.
(author)
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Treatment with a tissue-selective oestrogen complex does not affect disease pathology but reduces pre-BI cells in lupus-prone mice.
- 2024
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In: Scandinavian journal of rheumatology. - 1502-7732. ; 53:1, s. 49-58
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Journal article (peer-reviewed)abstract
- Systemic lupus erythematosus (SLE or lupus) is an autoimmune disease characterized by B-cell dysfunction, production of autoantibodies, and immune complex formation. Lupus is overrepresented in females, indicating that sex hormones play a role in the pathophysiology. Treatment with a tissue-selective oestrogen complex (TSEC) containing conjugated oestrogens and the selective oestrogen receptor modulator bazedoxifene (BZA) protects against postmenopausal vasomotor symptoms and osteoporosis, but its impact on organ damage in lupus is not fully understood.We used ovariectomized MRL/lpr mice, treated with two different physiological doses of 17β-oestradiol-3-benzoate (E2), BZA, or TSEC (E2 plus BZA), to assess early and late B-cell development and to determine histological disease manifestations in the kidneys and salivary glands.TSEC treatment reduced the frequency of the pre-BI population in bone marrow to levels equivalent to treatment with physiological doses of E2 alone but did not affect any of the other examined B-cell populations. Our earlier studies indicated that TSEC treatment did not aggravate disease development in ovariectomized MRL/lpr mice, while protecting against trabecular bone loss. Here, we follow up on our previous study and show that neither ovariectomy alone nor TSEC treatment of ovariectomized MRL/lpr mice influenced perivascular lymphocyte infiltration to the kidneys or salivary glands.TSEC does not aggravate a mouse model of lupus, when given in doses that protect against postmenopausal lupus-associated bone loss. This indicates that further investigations into TSEC as a treatment for osteoporosis or vasomotor symptoms in postmenopausal women with SLE are warranted.
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| 3. |
- Lawenius, Lina, et al.
(author)
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Transplantation of gut microbiota from old mice into young healthy mice reduces lean mass but not bone mass
- 2023
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In: Gut Microbes. - 1949-0976. ; 15:1
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Journal article (peer-reviewed)abstract
- Aging is associated with low bone and lean mass as well as alterations in the gut microbiota (GM). In this study, we determined whether the reduced bone mass and relative lean mass observed in old mice could be transferred to healthy young mice by GM transplantation (GMT). GM from old (21-month-old) and young adult (5-month-old) donors was used to colonize germ-free (GF) mice in three separate studies involving still growing 5- or 11-week-old recipients and 17-week-old recipients with minimal bone growth. The GM of the recipient mice was similar to that of the donors, demonstrating successful GMT. GM from old mice did not have statistically significant effects on bone mass or bone strength, but significantly reduced the lean mass percentage of still growing recipient mice when compared with recipients of GM from young adult mice. The levels of propionate in the cecum of mice receiving old donor GM were significantly lower than those in mice receiving young adult donor GM. Bacteroides ovatus was enriched in the microbiota of recipient mice harboring GM from young adult donors. The presence of B. ovatus was not only significantly associated with high lean mass percentage in mice, but also with lean mass adjusted for fat mass in the large human HUNT cohort. In conclusion, GM from old mice reduces lean mass percentage but not bone mass in young, healthy, still growing recipient mice. Future studies are warranted to determine whether GM from young mice improves the musculoskeletal phenotype of frail elderly recipient mice.
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| 4. |
- Sanchez Klose, Felix, 1989, et al.
(author)
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The Pseudomonas aeruginosa lectin LecB modulates intracellular reactive oxygen species production in human neutrophils
- 2024
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In: European Journal of Immunology. - 0014-2980 .- 1521-4141. ; 54:2
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Journal article (peer-reviewed)abstract
- Pseudomonas aeruginosa is a Gram-negative bacterium and an opportunistic pathogen ubiquitously present throughout nature. LecB, a fucose-, and mannose-binding lectin, is a prominent virulence factor of P. aeruginosa, which can be expressed on the bacterial surface but also be secreted. However, the LecB interaction with human immune cells remains to be characterized. Neutrophils comprise the first line of defense against infections and their production of reactive oxygen species (ROS) and release of extracellular traps (NETs) are critical antimicrobial mechanisms. When profiling the neutrophil glycome we found several glycoconjugates on granule and plasma membranes that could potentially act as LecB receptors. In line with this, we here show that soluble LecB can activate primed neutrophils to produce high levels of intracellular ROS (icROS), an effect that was inhibited by methyl fucoside. On the other hand, soluble LecB inhibits P. aeruginosa-induced icROS production. In support of that, during phagocytosis of wild-type and LecB-deficient P. aeruginosa, bacteria with LecB induced less icROS production as compared with bacteria lacking the lectin. Hence, LecB can either induce or inhibit icROS production in neutrophils depending on the circumstances, demonstrating a novel and potential role for LecB as an immunomodulator of neutrophil functional responses.
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