| 1. |
- Sondergaard, E., et al.
(författare)
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ERG Controls B Cell Development by Promoting Igh V-to-DJ Recombination
- 2019
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 29:9
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Tidskriftsartikel (refereegranskat)abstract
- B cell development depends on the coordinated expression and cooperation of several transcription factors. Here we show that the transcription factor ETS-related gene (ERG) is crucial for normal B cell development and that its deletion results in a substantial loss of bone marrow B cell progenitors and peripheral B cells, as well as a skewing of splenic B cell populations. We find that ERG-deficient B lineage cells exhibit an early developmental block at the pre-B cell stage and proliferate less. The cells fail to express the immunoglobulin heavy chain due to inefficient V-to-DJ recombination, and cells that undergo recombination display a strong bias against incorporation of distal V gene segments. Furthermore, antisense transcription at PAX5-activated intergenic repeat (PAIR) elements, located in the distal region of the Igh locus, depends on ERG. These findings show that ERG serves as a critical regulator of B cell development by ensuring efficient and balanced V-to-DJ recombination.
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| 2. |
- Wilhelmson, Anna S K, et al.
(författare)
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Testosterone is an endogenous regulator of BAFF and splenic B cell number
- 2018
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Testosterone deficiency in men is associated with increased risk for autoimmunity and increased B cell numbers through unknown mechanisms. Here we show that testosterone regulates the cytokine BAFF, an essential survival factor for B cells. Male mice lacking the androgen receptor have increased splenic B cell numbers, serum BAFF levels and splenic Baff mRNA. Testosterone deficiency by castration causes expansion of BAFF-producing fibro-blastic reticular cells (FRCs) in spleen, which may be coupled to lower splenic noradrenaline levels in castrated males, as an alpha-adrenergic agonist decreases splenic FRC number in vitro. Antibody-mediated blockade of the BAFF receptor or treatment with the neurotoxin 6-hydroxydopamine revert the increased splenic B cell numbers induced by castration. Among healthy men, serum BAFF levels are higher in men with low testosterone. Our study uncovers a previously unrecognized regulation of BAFF by testosterone and raises important questions about BAFF in testosterone-mediated protection against autoimmunity.
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| 3. |
- Lee, Po-Shun, et al.
(författare)
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mTORC1-S6K activation by endotoxin contributes to cytokine up-regulation and early lethality in animals.
- 2010
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 5:12
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Tidskriftsartikel (refereegranskat)abstract
- mTORC1 (mammalian target of rapamycin complex 1) activation has been demonstrated in response to endotoxin challenge, but the mechanism and significance are unclear. We investigated the effect of mTORC1 suppression in an animal model of endotoxemia and in a cellular model of endotoxin signaling.Mice were treated with the mTORC1 inhibitor rapamycin or vehicle prior to lethal endotoxin challenge. Mortality and cytokine levels were assessed. Cultured macrophage-like cells were challenged with endotoxin with or without inhibitors of various pathways known to be upstream of mTORC1. Activated pathways, including downstream S6K pathway, were assessed by immunoblots. We found that mTORC1-S6K suppression by rapamycin delayed mortality of mice challenged with lethal endotoxin, and was associated with dampened circulating levels of VEGF, IL-1β, IFN-γ and IL-5. Furthermore, in vitro cellular studies demonstrated that LPS (lipopolysaccharide) activation of mTORC1-S6K still occurs in the presence of PI3K-Akt inhibition alone, but can be suppressed by concurrent inhibition of PI3K-Akt and MEK-ERK pathways.We conclude that cellular activation of mTORC1-S6K contributes to cytokine up-regulation and mortality in response to endotoxin, and may occur via multiple pathways.
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| 4. |
- Stubelius, Alexandra, 1983, et al.
(författare)
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Sexual dimorphisms in the immune system of catechol-O-methyltransferase knockout mice
- 2012
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Ingår i: Immunobiology. - : Elsevier BV. - 0171-2985. ; 217:8, s. 751-760
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Tidskriftsartikel (refereegranskat)abstract
- The enzyme catechol-O-methyltransferase (COMT) is part of the metabolic pathway of 17 beta-estradiol, converting 2-hydroxyestradiol to 2-methoxyestradiol. We recently showed that administration of the COMT product 2-methoxyestradiol has anti-inflammatory and anti-osteoporotic effects. We have now investigated whether COMT affects the immune system, by immunologically phenotyping COMT deficient (COMT-/-) mice. Immunoglobulin production, T lymphocyte proliferation, NK cell cytotoxicity and oxygen radical production were assessed. In male COMT-/--mice, the total number of T-, and B-lymphocytes from spleen increased but the T-cell proliferative response decreased. The NK cell population shifted toward less mature cells, leaving cytotoxic capacity unaffected. In COMT-/--females, a higher frequency of neutrophils was found but the oxygen radical production was unaltered. In conclusion, only minor changes of the immune system were seen in COMT deficient mice, and the changes were usually seen in males. This study provides clues into how COMT activity, and hence gender differences, affects the immune system. (c) 2012 Elsevier GmbH. All rights reserved.
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| 5. |
- Wilhelmson, Anna S K, et al.
(författare)
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Catechol-O-methyltransferase is dispensable for vascular protection by estradiol in mouse models of atherosclerosis and neointima formation.
- 2011
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Ingår i: Endocrinology. - : The Endocrine Society. - 1945-7170 .- 0013-7227. ; 152:12, s. 4683-90
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Tidskriftsartikel (refereegranskat)abstract
- Estradiol is converted to the biologically active metabolite 2-methoxyestradiol via the activity of the enzyme catechol-O-methyltransferase (COMT). Exogenous administration of both estradiol and 2-methoxyestradiol reduces experimental atherosclerosis and neointima formation, and COMT-dependent formation of 2-methoxyestradiol likely mediates the antimitogenic effect of estradiol on smooth muscle cells in vitro. This study evaluated whether 2-methoxyestradiol mediates the vasculoprotective actions of estradiol in vivo. Wild-type (WT) and COMT knockout (COMTKO) mice on an apolipoprotein E-deficient background were gonadectomized and treated with estradiol or placebo. Exogenous estradiol reduced atherosclerotic lesion formation in both females (WT, -78%; COMTKO, -82%) and males (WT, -48%; COMTKO, -53%) and was equally effective in both genotypes. We further evaluated how exogenous estradiol affected neointima formation after ligation of the carotid artery in ovariectomized female mice; estradiol reduced intimal hyperplasia to a similar extent in both WT (-80%) and COMTKO (-77%) mice. In ovarian-intact female COMTKO mice, atherosclerosis was decreased (-25%) compared with WT controls. In conclusion, the COMT enzyme is dispensable for vascular protection by exogenous estradiol in experimental atherosclerosis and neointima formation in vivo. Instead, COMT deficiency in virgin female mice with intact endogenous production of estradiol results in relative protection against atherosclerosis.
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