| 1. |
- Dondalska, Aleksandra, et al.
(författare)
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Amelioration of Compound 48/80-Mediated Itch and LL-37-Induced Inflammation by a Single-Stranded Oligonucleotide
- 2020
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Ingår i: Frontiers in Immunology. - : FRONTIERS MEDIA SA. - 1664-3224. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Numerous inflammatory skin disorders display a high prevalence of itch. The Mas-related G protein coupled receptor X2 (MRGPRX2) has been shown to modulate itch by inducing non-IgE-mediated mast cell degranulation and the release of endogenous inducers of pruritus. Various substances collectively known as basic secretagogues, which include inflammatory peptides and certain drugs, can trigger MRGPRX2 and thereby induce pseudo-allergic reactions characterized by histamine and protease release as well as inflammation. Here, we investigated the capacity of an immunomodulatory single-stranded oligonucleotide (ssON) to modulate IgE-independent mast cell degranulation and, more specifically, its ability to inhibit the basic secretagogues compound 48/80 (C48/80)-and LL-37in vitroandin vivo. We examined the effect of ssON on MRGPRX2 activationin vitroby measuring degranulation in a human mast cell line (LAD2) and calcium influx in MRGPRX2-transfected HEK293 cells. To determine the effect of ssON on itch, we performed behavioral studies in established mouse models and collected skin biopsies for histological analysis. Additionally, with the use of a rosacea mouse model and RT-qPCR, we investigated the effect on ssON on LL-37-induced inflammation. We reveal that both mast cell degranulation and calcium influx in MRGPRX2 transfected HEK293 cells, induced by the antimicrobial peptide LL-37 and the basic secretagogue C48/80, are effectively inhibited by ssON in a dose-dependent manner. Further, ssON demonstrates a capability to inhibit LL-37 and C48/80 activationin vivoin two mouse models. We show that intradermal injection of ssON in mice is able to block itch induced via C48/80 in a dose-dependent manner. Histological staining revealed that ssON inhibits acute mast cell degranulation in murine skin treated with C48/80. Lastly, we show that ssON treatment ameliorates LL-37-induced inflammation in a rosacea mouse model. Since there is a need for new therapeutics targeting non-IgE-mediated activation of mast cells, ssON could be used as a prospective drug candidate to resolve itch and inflammation in certain dermatoses.
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| 2. |
- Johnsson, Anna-Karin, et al.
(författare)
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Selective inhibition of prostaglandin D-2 biosynthesis in human mast cells to overcome need for multiple receptor antagonists : Biochemical consequences
- 2021
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Ingår i: Clinical and Experimental Allergy. - : John Wiley & Sons. - 0954-7894 .- 1365-2222. ; 51:4, s. 594-603
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Tidskriftsartikel (refereegranskat)abstract
- Background The major mast cell prostanoid PGD(2) is targeted for therapy of asthma and other diseases, because the biological actions include bronchoconstriction, vasodilation and regulation of immune cells mediated by three different receptors. It is not known if the alternative to selectively inhibit the biosynthesis of PGD(2) affects release of other prostanoids in human mast cells. Objectives To determine the biochemical consequences of inhibition of the hematopoietic prostaglandin D synthase (hPGDS) PGD(2) in human mast cells. Methods Four human mast cell models, LAD2, cord blood derived mast cells (CBMC), peripheral blood derived mast cells (PBMC) and human lung mast cells (HLMC), were activated by anti-IgE or ionophore A23187. Prostanoids were measured by UPLC-MS/MS. Results All mast cells almost exclusively released PGD(2) when activated by anti-IgE or A23187. The biosynthesis was in all four cell types entirely initiated by COX-1. When pharmacologic inhibition of hPGDS abolished formation of PGD(2), PGE(2) was detected and release of TXA(2) increased. Conversely, when the thromboxane synthase was inhibited, levels of PGD(2) increased. Adding exogenous PGH(2) confirmed predominant conversion to PGD(2) under control conditions, and increased levels of TXB2 and PGE(2) when hPGDS was inhibited. However, PGE(2) was formed by non-enzymatic degradation. Conclusions Inhibition of hPGDS effectively blocks mast cell dependent PGD(2) formation. The inhibition was associated with redirected use of the intermediate PGH(2) and shunting into biosynthesis of TXA(2). However, the levels of TXA(2) did not reach those of PGD(2) in naive cells. It remains to determine if this diversion occurs in vivo and has clinical relevance.
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| 3. |
- Ronnberg, Elin, et al.
(författare)
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Analysis of human lung mast cells by single cell RNA sequencing
- 2023
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Ingår i: Frontiers in Immunology. - : Frontiers Media S.A.. - 1664-3224. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Mast cells are tissue-resident cells playing major roles in homeostasis and disease conditions. Lung mast cells are particularly important in airway inflammatory diseases such as asthma. Human mast cells are classically divided into the subsets MCT and MCTC, where MCT express the mast cell protease tryptase and MCTC in addition express chymase, carboxypeptidase A3 (CPA3) and cathepsin G. Apart from the disctintion of the MCT and MCTC subsets, little is known about the heterogeniety of human lung mast cells and a deep analysis of their heterogeniety has previously not been performed. We therefore performed single cell RNA sequencing on sorted human lung mast cells using SmartSeq2. The mast cells showed high expression of classical mast cell markers. The expression of several individual genes varied considerably among the cells, however, no subpopulations were detected by unbiased clustering. Variable genes included the protease-encoding transcripts CMA1 (chymase) and CTSG (cathepsin G). Human lung mast cells are predominantly of the MCT subset and consistent with this, the expression of CMA1 was only detectable in a small proportion of the cells, and correlated moderately to CTSG. However, in contrast to established data for the protein, CPA3 mRNA was high in all cells and the correlation of CPA3 to CMA1 was weak.
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| 4. |
- Ronnberg, Elin, et al.
(författare)
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Immunoprofiling Reveals Novel Mast Cell Receptors and the Continuous Nature of Human Lung Mast Cell Heterogeneity
- 2022
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Ingår i: Frontiers in Immunology. - : Frontiers Media S.A.. - 1664-3224. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Immunohistochemical analysis of granule-associated proteases has revealed that human lung mast cells constitute a heterogeneous population of cells, with distinct subpopulations identified. However, a systematic and comprehensive analysis of cell-surface markers to study human lung mast cell heterogeneity has yet to be performed.Methods: Human lung mast cells were obtained from lung lobectomies, and the expression of 332 cell-surface markers was analyzed using flow cytometry and the LEGENDScreen (TM) kit. Markers that exhibited high variance were selected for additional analyses to reveal whether they were correlated and whether discrete mast cell subpopulations were discernable.Results: We identified the expression of 102 surface markers on human lung mast cells, 23 previously not described on mast cells, of which several showed high continuous variation in their expression. Six of these markers were correlated: SUSD2, CD49a, CD326, CD34, CD66 and HLA-DR. The expression of these markers was also correlated with the size and granularity of mast cells. However, no marker produced an expression profile consistent with a bi- or multimodal distribution.Conclusions: LEGENDScreen analysis identified more than 100 cell-surface markers on mast cells, including 23 that, to the best of our knowledge, have not been previously described on human mast cells. The comprehensive expression profiling of the 332 surface markers did not identify distinct mast cell subpopulations. Instead, we demonstrate the continuous nature of human lung mast cell heterogeneity.
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| 5. |
- Tang, Xiao, et al.
(författare)
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Activation of succinate receptor 1 boosts human mast cell reactivity and allergic bronchoconstriction
- 2022
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Ingår i: Allergy. European Journal of Allergy and Clinical Immunology. - : John Wiley & Sons. - 0105-4538 .- 1398-9995. ; 77:9, s. 2677-2687
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Tidskriftsartikel (refereegranskat)abstract
- Background SUCNR1 is a sensor of extracellular succinate, a Krebs cycle intermediate generated in excess during oxidative stress and has been linked to metabolic regulation and inflammation. While mast cells express SUCNR1, its role in mast cell reactivity and allergic conditions such as asthma remains to be elucidated. Methods Cord blood-derived mast cells and human mast cell line LAD-2 challenged by SUCNR1 ligands were analyzed for the activation and mediator release. Effects on mast cell-dependent bronchoconstriction were assessed in guinea pig trachea and isolated human small bronchi challenged with antigen and anti-IgE, respectively. Results SUCNR1 is abundantly expressed on human mast cells. Challenge with succinate, or the synthetic non-metabolite agonist cis-epoxysuccinate, renders mast cells hypersensitive to IgE-dependent activation, resulting in augmented degranulation and histamine release, de novo biosynthesis of eicosanoids and cytokine secretion. The succinate-potentiated mast cell reactivity was attenuated by SUCNR1 knockdown and selective SUCNR1 antagonists and could be tuned by pharmacologically targeting protein kinase C and extracellular signal-regulated kinase. Both succinate and cis-epoxysuccinate dose-dependently potentiated antigen-induced contraction in a mast cell-dependent guinea pig airway model, associated with increased generation of cysteinyl-leukotrienes and histamine in trachea. Similarly, cis-epoxysuccinate aggravated IgE-receptor-induced contraction of human bronchi, which was blocked by SUCNR1 antagonism. Conclusion SUCNR1 amplifies IgE-receptor-induced mast cell activation and allergic bronchoconstriction, suggesting a role for this pathway in aggravation of allergic asthma, thus linking metabolic perturbations to mast cell-dependent inflammation.
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