| 1. |
- Alanazi, Sultan, et al.
(author)
-
Mast Cell β-Tryptase Is Enzymatically Stabilized by DNA
- 2020
-
In: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 21:14
-
Journal article (peer-reviewed)abstract
- Tryptase is a tetrameric serine protease located within the secretory granules of mast cells. In the secretory granules, tryptase is stored in complex with negatively charged heparin proteoglycans and it is known that heparin is essential for stabilizing the enzymatic activity of tryptase. However, recent findings suggest that enzymatically active tryptase also can be found in the nucleus of murine mast cells, but it is not known how the enzmatic activity of tryptase is maintained in the nuclear milieu. Here we hypothesized that tryptase, as well as being stabilized by heparin, can be stabilized by DNA, the rationale being that the anionic charge of DNA could potentially substitute for that of heparin to execute this function. Indeed, we showed that double-stranded DNA preserved the enzymatic activity of human β-tryptase with a similar efficiency as heparin. In contrast, single-stranded DNA did not have this capacity. We also demonstrated that DNA fragments down to 400 base pairs have tryptase-stabilizing effects equal to that of intact DNA. Further, we showed that DNA-stabilized tryptase was more efficient in degrading nuclear core histones than heparin-stabilized enzyme. Finally, we demonstrated that tryptase, similar to its nuclear localization in murine mast cells, is found within the nucleus of primary human skin mast cells. Altogether, these finding reveal a hitherto unknown mechanism for the stabilization of mast cell tryptase, and these findings can have an important impact on our understanding of how tryptase regulates nuclear events.
|
|
| 2. |
- Alim, Abdul, 1983-, et al.
(author)
-
Glutamate triggers the expression of functional ionotropic and metabotropic glutamate receptors in mast cells
- 2021
-
In: Cellular & Molecular Immunology. - : Springer Nature. - 1672-7681 .- 2042-0226. ; 18:10, s. 2383-2392
-
Journal article (peer-reviewed)abstract
- Mast cells are emerging as players in the communication between peripheral nerve endings and cells of the immune system. However, it is not clear the mechanism by which mast cells communicate with peripheral nerves. We previously found that mast cells located within healing tendons can express glutamate receptors, raising the possibility that mast cells may be sensitive to glutamate signaling. To evaluate this hypothesis, we stimulated primary mast cells with glutamate and showed that glutamate induced the profound upregulation of a panel of glutamate receptors of both the ionotropic type (NMDAR1, NMDAR2A, and NMDAR2B) and the metabotropic type (mGluR2 and mGluR7) at both the mRNA and protein levels. The binding of glutamate to glutamate receptors on the mast cell surface was confirmed. Further, glutamate had extensive effects on gene expression in the mast cells, including the upregulation of pro-inflammatory components such as IL-6 and CCL2. Glutamate also induced the upregulation of transcription factors, including Egr2, Egr3 and, in particular, FosB. The extensive induction of FosB was confirmed by immunofluorescence assessment. Glutamate receptor antagonists abrogated the responses of the mast cells to glutamate, supporting the supposition of a functional glutamate-glutamate receptor axis in mast cells. Finally, we provide in vivo evidence supporting a functional glutamate-glutamate receptor axis in the mast cells of injured tendons. Together, these findings establish glutamate as an effector of mast cell function, thereby introducing a novel principle for how cells in the immune system can communicate with nerve cells.
|
|
| 3. |
- Braga, Tiago, et al.
(author)
-
Serglycin proteoglycan is required for secretory granule integrity in mucosal mast cells
- 2007
-
In: Biochemical Journal. - 0264-6021 .- 1470-8728. ; 403:1, s. 49-57
-
Journal article (peer-reviewed)abstract
- SG (serglycin) PGs (proteoglycans) are strongly implicated in the assembly of MC (mast cell) granules. However, this notion has mainly been on the basis of studies of MCs of the connective tissue subtype, whereas the role of SG PG in mucosal MCs has not been explored. In the present study, we have addressed the latter issue by using mice with an inactivated SG gene. Bone marrow cells were differentiated in vitro into the mucosal MC phenotype, expressing the markers mMCP (mouse MC protease) -1 and -2. Biosynthetic labelling experiments performed on these cells revealed an ~80% reduction of 35SO42− incorporation into PGs recovered from SG−/− cells as compared with SG+/+ counterparts, indicating that SG is the dominating cell-associated PG of mucosal MCs. Moreover, the absence of SG led to defective metachromatic staining of mucosal MCs, both in vivo and in the in vitro-derived mucosal MCs. Ultrastructural analysis showed that granules were present in similar numbers in SG+/+ and SG−/− cells, but that their morphology was markedly affected by the absence of SG, e.g. with electron-dense core formation only seen in SG+/+ granules. Analysis of the MC-specific proteases showed that mMCP-1 and mMCP-7 were completely independent of SG for storage, whereas mMCP-2 showed a partial dependence. In contrast, mMCP-4 and -6, and carboxypeptidase A were strongly dependent on SG for storage. Together, our data indicate that SG PG is of crucial importance for assembly of mature mucosal MC granules, but that the specific dependence on SG for storage varies between individual granule constituents.
|
|
| 4. |
- Doncheva, Atanaska, I, et al.
(author)
-
Serglycin Is Involved in Adipose Tissue Inflammation in Obesity
- 2022
-
In: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 208:1, s. 121-132
-
Journal article (peer-reviewed)abstract
- Chronic local inflammation of adipose tissue is an important feature of obesity. Serglycin is a proteoglycan highly expressed by various immune cell types known to infiltrate adipose tissue under obese conditions. To investigate if serglycin expression has an impact on diet-induced adipose tissue inflammation, we subjected Srgn(+/+) and Srgn(-/-) mice (C57BL/6J genetic background) to an 8-wk high-fat and high-sucrose diet. The total body weight was the same in Srgn(+/+) and Srgn(-/-) mice after diet treatment. Expression of white adipose tissue genes linked to inflammatory pathways were lower in Srgn(-/)- mice. We also noted reduced total macrophage abundance, a reduced proportion of proinflammatory M1 macrophages, and reduced formation of crown-like structures in adipose tissue of Srgn(-/-) compared with Srgn(+/+) mice. Further, Srgn(-/-) mice had more medium-sized adipocytes and fewer large adipocytes. Differentiation of preadipocytes into adipocytes (3T3-L1) was accompanied by reduced Srgn mRNA expression. In line with this, analysis of single-cell RNA sequencing data from mouse and human adipose tissue supports that Srgn mRNA is predominantly expressed by various immune cells, with low expression in adipocytes. Srgn mRNA expression was higher in obese compared with lean humans and mice, accompanied by an increased expression of immune cell gene markers. SRGN and inflammatory marker mRNA expression was reduced upon substantial weight loss in patients after bariatric surgery. Taken together, this study introduces a role for serglycin in the regulation of obesity-induced adipose inflammation.
|
|
| 5. |
|
|
| 6. |
- Faroldi, Gianni, et al.
(author)
-
Active Caspase-3 Is Stored within Secretory Compartments of Viable Mast Cells
- 2013
-
In: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 191, s. 1445-1452
-
Journal article (peer-reviewed)abstract
- Caspase-3 is a main executioner of apoptotic cell death. The general notion is that, in viable cells, caspase-3 is found as a cytosolic inactive proenzyme and that caspase-3 activation is largely confined to processes associated with cell death. In this study, we challenge this notion by showing that enzymatically active caspase-3 is stored in viable mast cells. The enzymatically active caspase-3 was undetectable in the cytosol of viable cells, but was recovered in subcellular fractions containing secretory granule-localized proteases. Moreover, active caspase-3 was rapidly released into the cytosolic compartment after permeabilization of the secretory granules. Using a cell-permeable substrate for caspase-3, the presence of active caspase-3-like activity in granule-like compartments close to the plasma membrane was demonstrated. Moreover, it was shown that mast cell activation caused release of the caspase-3 to the cell exterior. During the course of mast cell differentiation from bone marrow cells, procaspase-3 was present in cells of all stages of maturation. In contrast, active caspase-3 was undetectable in bone marrow precursor cells, but increased progressively during the process of mast cell maturation, its accumulation coinciding with that of a mast cell-specific secretory granule marker, mouse mast cell protease 6. Together, the current study suggests that active caspase-3 can be stored within secretory compartments of viable mast cells.
|
|
| 7. |
- Garcia-Faroldi, Gianni, et al.
(author)
-
Inhibition of the BET family of epigenetic reader proteins : A novel principle for modulating gene expression in IgE-activated mast cells
- 2017
-
In: Immunity, Inflammation and Disease. - : Wiley. - 2050-4527. ; 5:2, s. 141-150
-
Journal article (peer-reviewed)abstract
- Introduction: The BET family of bromodomain-containing proteins constitute epigenetic readers that bind to acetylated lysine residues of core histones, thereby translating epigenetic histone marks to effects on gene expression. BET inhibitors are currently emerging as promising therapeutic agents for treatment of various pathological conditions. Here, we explored the potential of using BET inhibition to modulate IgE-mediated responses in mast cells.Methods: We assessed the effects of BET inhibitors PFI-1, I-BET151, and I-BET762 on responses downstream of mast cell activation through IgE receptor cross-linking.Results: BET inhibitors were neither toxic for mast cells (at doses up to 20M), nor did they prevent IgE-mediated mast cell degranulation. However, we found that BET inhibition, in particular by I-BET151, suppressed IL-6 gene expression and IL-6 protein release in response to IgE-mediated mast cell activation. This was observed in both bone marrow-derived mast cells (BMMCs) and in mature peritoneal-cell derived mast cells. Further analysis showed that BET inhibition also suppressed the expression of a number of additional genes of those that were upregulated by IgE receptor cross-linking, including IL-3, IL-7R, CCR1, and ADAMTS9. However, BET inhibition was selective, i.e., several genes that were upregulated by IgE receptor cross-linking were not affected by BET inhibitors.Conclusions: These findings suggest that BET inhibition can interfere with the upregulated expression of selected genes in mast cells activated by IgE receptor cross-linking. Further, our findings introduce the concept of utilizing epigenetic mechanisms for modulating mast cell function in the context of IgE-driven disease.
|
|
| 8. |
- Grujic, Mirjana, et al.
(author)
-
Delayed contraction of the CD8+ T cell response toward lymphocytic choriomeningitis virus infection in mice lacking serglycin
- 2008
-
In: Journal of Immunology. - 0022-1767 .- 1550-6606. ; 181:2, s. 1043-1051
-
Journal article (peer-reviewed)abstract
- We previously reported that the lack of serglycin proteoglycan affects secretory granule morphology and granzyme B (GrB) storage in in vitro generated CTLs. In this study, the role of serglycin during viral infection was studied by infecting wild-type (wt) mice and serglycin-deficient (SG(-/-)) mice with lymphocytic choriomeningitis virus (LCMV). Wt and SG(-/-) mice cleared 10(3) PFU of highly invasive LCMV with the same kinetics, and the CD8(+) T lymphocytes from wt and SG(-/-) animals did not differ in GrB, perforin, IFN-gamma, or TNF-alpha content. However, when a less invasive LCMV strain was used, SG(-/-) GrB(+) CD8(+) T cells contained approximately 30% less GrB than wt GrB(+) CD8(+) T cells. Interestingly, the contraction of the antiviral CD8(+) T cell response to highly invasive LCMV was markedly delayed in SG(-/-) mice, and a delayed contraction of the virus-specific CD8(+) T cell response was also seen after infection with vesicular stomatitis virus. BrdU labeling of cells in vivo revealed that the delayed contraction was associated with sustained proliferation of Ag-specific CD8(+) T cells in SG(-/-) mice. Moreover, wt LCMV-specific CD8(+) T cells from TCR318 transgenic mice expanded much more extensively in virus-infected SG(-/-) mice than in matched wt mice, indicating that the delayed contraction represents a T cell extrinsic phenomenon. In summary, the present report points to a novel, previously unrecognized role for serglycin proteoglycan in regulating the kinetics of antiviral CD8(+) T cell responses.
|
|
| 9. |
- Grujic, Mirjana, et al.
(author)
-
Distorted Secretory Granule Composition in Mast Cells with Multiple Protease Deficiency
- 2013
-
In: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 191:7, s. 3931-3938
-
Journal article (peer-reviewed)abstract
- Mast cells are characterized by an abundance of secretory granules densely packed with inflammatory mediators such as bioactive amines, cytokines, serglycin proteoglycans with negatively charged glycosaminoglycan side chains of either heparin or chondroitin sulfate type, and large amounts of positively charged proteases. Despite the large biological impact of mast cell granules and their contents on various pathologies, the mechanisms that regulate granule composition are incompletely understood. In this study, we hypothesized that granule composition is dependent on a dynamic electrostatic interrelationship between different granule compounds. As a tool to evaluate this possibility, we generated mice in which mast cells are multideficient in a panel of positively charged proteases: the chymase mouse mast cell protease-4, the tryptase mouse mast cell protease-6, and carboxypeptidase A3. Through a posttranslational effect, mast cells from these mice additionally lack mouse mast cell protease-5 protein. Mast cells from mice deficient in individual proteases showed normal morphology. In contrast, mast cells with combined protease deficiency displayed a profound distortion of granule integrity, as seen both by conventional morphological criteria and by transmission electron microscopy. An assessment of granule content revealed that the distorted granule integrity in multiprotease-deficient mast cells was associated with a profound reduction of highly negatively charged heparin, whereas no reduction in chondroitin sulfate storage was observed. Taken together with previous findings showing that the storage of basic proteases conversely is regulated by anionic proteoglycans, these data suggest that secretory granule composition in mast cells is dependent on a dynamic interrelationship between granule compounds of opposite electrical charge.
|
|
| 10. |
- Grujic, Mirjana, et al.
(author)
-
Phenotypic Switch and Growth of Melanoma Spheroids in the Presence of Mast Cells : Potential Impact of Nutrient-starvation Effects
- 2023
-
In: Anticancer Research. - : International Institute of Anticancer Research. - 0250-7005 .- 1791-7530. ; 43:4, s. 1415-1426
-
Journal article (peer-reviewed)abstract
- Background/Aim: Mast cells are abundant in melanoma tumors, and studies suggest that they can be either detrimental or protective for melanoma growth. However, the underlying mechanisms are not fully understood.Materials and Methods: Here, we adopted an established hanging-drop spheroid system to investigate how mast cells influence melanoma growth and phenotype in a 3-D context. To address the underlying mechanism, we conducted transcriptomic and pathway analyses.Results: In the presence of mast cells or mast cell-conditioned medium, growth of melanoma spheroids was profoundly reduced. Transcriptomic analysis revealed that mast cell-conditioned medium had extensive effects on the gene-expression patterns of melanoma. Pathway analyses revealed profound effects on the expression of genes related to amino acid and protein metabolism. The conditioned medium also induced up-regulation of cancer-related genes, including adhesion molecules implicated in metastatic spreading. In line with this, after transfer to a Matrigel extracellular matrix milieu, spheroids that had been developed in the presence of mast cell-conditioned medium displayed enhanced growth and adhesive properties. However, when assessing the possible impact of nutrient starvation, i.e., reduced nutrient content in mast cell-conditioned medium, we found that the observed effects on growth of melanoma spheroids could potentially be explained by such a scenario.Conclusion: Our findings suggest that the phenotypic alterations of melanoma spheroids grown in the presence of mast cells or mast cell-conditioned media are, at least partly, due to nutrient starvation rather than to the action of factors secreted by mast cells. Our findings may provide insight into the effects on gene-expression events that occur in melanoma tumors under nutrient stress.
|
|
| 11. |
- Grujic, Mirjana, et al.
(author)
-
Protective role of mouse mast cell tryptase Mcpt6 in melanoma.
- 2020
-
In: Pigment Cell & Melanoma Research. - : Wiley. - 1755-1471 .- 1755-148X. ; 33:4, s. 579-590
-
Journal article (peer-reviewed)abstract
- Tryptase-positive mast cells populate melanomas, but it is not known whether tryptase impacts on melanoma progression. Here we addressed this and show that melanoma growth is significantly higher in tryptase-deficient (Mcpt6-/- ) versus wild-type mice. Histochemical analysis showed that mast cells were frequent in the tumor stroma of both wild-type and Mcpt6-/- mice, and also revealed their presence within the tumor parenchyma. Confocal microscopy analysis revealed that tryptase was taken up by the tumor cells. Further, tryptase-positive granules were released from mast cells and were widely distributed within the tumor tissue, suggesting that tryptase could impact on the tumor microenvironment. Indeed, gene expression analysis showed that the absence of Mcpt6 caused decreased expression of numerous genes, including Cxcl9, Tgtp2, and Gbp10, while the expression of 5p-miR3098 was enhanced. The levels of CXCL9 were lower in serum from Mcpt6-/- versus wild-type mice. In further support of a functional impact of tryptase on melanoma, recombinant tryptase (Mcpt6) was taken up by cultured melanoma cells and caused reduced proliferation. Altogether, our results indicate a protective role of mast cell tryptase in melanoma growth.
|
|
| 12. |
- Grujic, Mirjana, et al.
(author)
-
The combined action of mast cell chymase, tryptase and carboxypeptidase A3 protects against melanoma colonization of the lung
- 2017
-
In: Oncotarget. - : IMPACT JOURNALS LLC. - 1949-2553. ; 8:15, s. 25066-25079
-
Journal article (peer-reviewed)abstract
- Mast cell secretory granules are densely packed with various bioactive mediators including proteases of chymase, tryptase and CPA3 type. Previous studies have indicated that mast cells can affect the outcome of melanoma but the contribution of the mast cell granule proteases to such effects has not been clear. Here we addressed this issue by assessing mice lacking either the chymase Mcpt4, the tryptase Mcpt6 or carboxypeptidase A3 (Cpa3), as well as mice simultaneously lacking all three proteases, in a model of melanoma dissemination from blood to the lung. Although mice with individual deficiency in the respective proteases did not differ significantly from wildtype mice in the extent of melanoma colonization, mice with multiple protease deficiency (Mcpt4/Mcpt6/Cpa3-deficient) exhibited a higher extent of melanoma colonization in lungs as compared to wildtype animals. This was supported by higher expression of melanoma-specific genes in lungs of Mcpt4/Mcpt6/CPA3-deficient vs. wildtype mice. Cytokine profiling showed that the levels of CXCL16, a chemokine with effects on T cell populations and NKT cells, were significantly lower in lungs of Mcpt4/Mcpt6/Cpa3-deficient animals vs. controls, suggesting that multiple mast cell protease deficiency might affect T cell or NKT cell populations. In line with this, we found that the Mcpt4/Mcpt6/Cpa3-deficiency was associated with a reduction in cells expressing CD1d, a MHC class 1-like molecule that is crucial for presenting antigen to invariant NKT (iNKT) cells. Together, these findings indicate a protective role of mast cell-specific proteases in melanoma dissemination, and suggest that this effect involves a CXCL16/CD1d/NKT cell axis.
|
|
| 13. |
- Hellberg, Åsa, et al.
(author)
-
A novel nonsense variant in RHAG underlies a Nordic Rhnull phenotype
- 2023
-
In: Vox Sanguinis. - : John Wiley & Sons. - 0042-9007 .- 1423-0410. ; 118:8, s. 690-694
-
Journal article (peer-reviewed)abstract
- Background and ObjectivesThe extremely rare Rhnull phenotype is characterized by the absence of all Rh antigens on erythrocytes. It is divided into the regulator and amorph types based on the underlying genetic background. The more common regulator type depends on critical variants silencing RHAG, which encodes RhAG glycoprotein, necessary for RhD/RhCE expression. Rhnull cells have altered expression of glycophorin B and LW glycoprotein.Materials and MethodsFour unrelated Rhnull individuals were investigated. Serological testing was performed according to standard blood bank practice. RHD/RHCE and S/s allele-specific Polymerase chain reaction (PCR) genotyping was done on genomic DNA using in-house PCR assays. RHAG, and in some cases also RHD/RHCE, were sequenced. Initial s phenotyping results triggered additional serological investigation.ResultsAnti-Rh29 was identified in all four individuals. Extended typing with anti-S and anti-s showed that the three samples predicted to type as s+ failed to react with 2 of 5 anti-s. Sequence analysis of all 10 RHAG exons and the immediate intron/exon boundaries revealed a single nucleotide variant in the 3′-end of intron 6, c.946 −2a>g in all samples. RHD/RHCE showed no alterations.ConclusionA novel Nordic Rhnull allele was identified. In addition, it was shown that s+ Rhnull red blood cells are not only U− but also have qualitative changes in their s antigen expression.
|
|
| 14. |
|
|
| 15. |
- Magnúsdóttir, Elín Ingibjörg, et al.
(author)
-
Mouse connective tissue mast cell proteases tryptase and carboxypeptidase A3 play protective roles in itch induced by endothelin-1
- 2020
-
In: Journal of Neuroinflammation. - : BMC. - 1742-2094. ; 17
-
Journal article (peer-reviewed)abstract
- Background: Itch is an unpleasant sensation that can be debilitating, especially if it is chronic and of non-histaminergic origin, as treatment options are limited. Endothelin-1 (ET-1) is a potent endogenous vasoconstrictor that also has the ability to induce a burning, non-histaminergic pruritus when exogenously administered, by activating the endothelin A receptor (ETAR) on primary afferents. ET-1 is released endogenously by several cell-types found in the skin, including macrophages and keratinocytes. Mast cells express ET(A)Rs and can thereby be degranulated by ET-1, and mast cell proteases chymase and carboxypeptidase A3 (CPA3) are known to either generate or degrade ET-1, respectively, suggesting a role for mast cell proteases in the regulation of ET-1-induced itch. The mouse mast cell proteases (mMCPs) mMCP4 (chymase), mMCP6 (tryptase), and CPA3 are found in connective tissue type mast cells and are the closest functional homologs to human mast cell proteases, but little is known about their role in endothelin-induced itch.Methods: In this study, we evaluated the effects of mast cell protease deficiency on scratching behavior induced by ET-1. To investigate this, mMCP knock-out and transgenic mice were injected intradermally with ET-1 and their scratching behavior was recorded and analyzed.Results: CPA3-deficient mice and mice lacking all three proteases demonstrated highly elevated levels of scratching behavior compared with wild-type controls. A modest increase in the number of scratching bouts was also seen in mMCP6-deficient mice, while mMCP4-deficiency did not have any effect.Conclusion: Altogether, these findings identify a prominent role for the mast cell proteases, in particular CPA3, in the protection against itch induced by ET-1.
|
|
| 16. |
|
|
| 17. |
- Magnúsdóttir, Elín Ingibjörg, et al.
(author)
-
Mouse mast cells and mast cell proteases do not play a significant role in acute tissue injury pain induced by formalin
- 2018
-
In: Molecular Pain. - : SAGE Publications. - 1744-8069. ; 14
-
Journal article (peer-reviewed)abstract
- Subcutaneous formalin injections are used as a model for tissue injury-induced pain where formalin induces pain and inflammation indirectly by crosslinking proteins and directly through activation of the transient receptor potential A1 receptor on primary afferents. Activation of primary afferents leads to both central and peripheral release of neurotransmitters. Mast cells are found in close proximity to peripheral sensory nerve endings and express receptors for neurotransmitters released by the primary afferents, contributing to the neuro/immune interface. Mast cell proteases are found in large quantities within mast cell granules and are released continuously in small amounts and upon mast cell activation. They have a wide repertoire of proposed substrates, including Substance P and calcitonin gene-related peptide, but knowledge of their in vivo function is limited. We evaluated the role of mouse mast cell proteases (mMCPs) in tissue injury pain responses induced by formalin, using transgenic mice lacking either mMCP4, mMCP6, or carboxypeptidase A3 (CPA3), or mast cells in their entirety. Further, we investigated the role of mast cells in heat hypersensitivity following a nerve growth factor injection. No statistical difference was observed between the respective mast cell protease knockout lines and wild-type controls in the formalin test. Mast cell deficiency did not have an effect on formalin-induced nociceptive responses nor nerve growth factor-induced heat hypersensitivity. Our data thus show that mMCP4, mMCP6, and CPA3 as well as mast cells as a whole, do not play a significant role in the pain responses associated with acute tissue injury and inflammation in the formalin test. Our data also indicate that mast cells are not essential to heat hypersensitivity induced by nerve growth factor.
|
|
| 18. |
|
|
| 19. |
- Melo, Fabio rabelo, et al.
(author)
-
Serglycin Proteoglycan Promotes Apoptotic versus Necrotic Cell Death in Mast Cells
- 2012
-
In: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 287, s. 18142-18152
-
Journal article (peer-reviewed)abstract
- The mechanisms that govern whether a cell dies by apoptosis or necrosis are not fully understood. Here we show that serglycin, a secretory granule proteoglycan of hematopoietic cells, can have a major impact on this decision. Wild type and serglycin(-/-) mast cells were equally sensitive to a range of cell death-inducing regimens. However, whereas wild type mast cells underwent apoptotic cell death, serglycin(-/-) cells died predominantly by necrosis. Investigations of the underlying mechanism revealed that cell death was accompanied by leakage of secretory granule compounds into the cytosol and that the necrotic phenotype of serglycin(-/-) mast cells was linked to defective degradation of poly(ADP-ribose) polymerase-1. Cells lacking mouse mast cell protease 6, a major serglycin-associated protease, exhibited similar defects in apoptosis as observed in serglycin(-/-) cells, indicating that the pro-apoptotic function of serglycin is due to downstream effects of proteases that are complex-bound to serglycin. Together, these findings implicate serglycin in promoting apoptotic versus necrotic cell death.
|
|
| 20. |
|
|
| 21. |
- Pejler, Gunnar, et al.
(author)
-
Mast cell tryptase potentiates neutrophil extracellular trap formation
- 2022
-
In: Journal of Innate Immunity. - : S. Karger. - 1662-811X .- 1662-8128. ; 14:5, s. 433-446
-
Journal article (peer-reviewed)abstract
- Previous research has indicated an intimate functional communication between mast cells and neutrophils during inflammatory conditions, but the nature of such communication is not fully understood. Activated neutrophils are known to release DNA-containing extracellular traps (NETs) and, based on the known ability of tryptase to interact with negatively charged polymers, we here hypothesized that tryptase might interact with NET-contained DNA and thereby regulate NET formation. In support of this, we show that tryptase markedly enhances NET formation in phorbol myristate acetate (PMA)-activated human neutrophils. Moreover, tryptase was found to bind vividly to the NETs, to cause proteolysis of core histones and to cause a reduction in the levels of citrullinated histone-3. Secretome analysis revealed that tryptase caused increased release of numerous neutrophil granule compounds, including gelatinase, lactoferrin and myeloperoxidase. We also show that DNA can induce the tetrameric, active organization of tryptase, suggesting that NET-contained DNA can maintain tryptase activity in the extracellular milieu. In line with such a scenario, DNA-stabilized tryptase was shown to efficiently degrade numerous pro-inflammatory compounds. Finally, we show that tryptase is associated with NET formation in vivo in a melanoma setting, and that NET formation in vivo is attenuated in mice lacking tryptase expression. Altogether, these findings reveal that NET formation can be regulated by mast cell tryptase, thus introducing a novel mechanism of communication between mast cells and neutrophils.
|
|
| 22. |
- Rönnberg, Elin, et al.
(author)
-
Mast cells are activated by Staphylococcus aureus in vitro but do not influence the outcome of intraperitoneal S. aureus infection in vivo
- 2014
-
In: Immunology. - : Wiley. - 0019-2805 .- 1365-2567. ; 143:2, s. 155-163
-
Journal article (peer-reviewed)abstract
- Staphylococcus aureus is a major pathogen that can cause a broad spectrum of serious infections including skin infections, pneumonia and sepsis. Peritoneal mast cells have been implicated in the host response towards various bacterial insults and to provide mechanistic insight into the role of mast cells in intraperitoneal bacterial infection we here studied the global effects of S. aureus on mast cell gene expression. After co-culture of peritoneal mast cells with live S. aureus we found by gene array analysis that they up-regulate a number of genes. Many of these corresponded to pro-inflammatory cytokines, including interleukin-3, interleukin-13 and tumour necrosis factor-a. The cytokine induction in response to S. aureus was confirmed by ELISA. To study the role of peritoneal mast cells during in vivo infection with S. aureus we used newly developed Mcpt5-Cre(+) x R-DTA mice in which mast cell deficiency is independent of c-Kit. This is in contrast to previous studies in which an impact of mast cells on bacterial infection has been proposed based on the use of mice whose mast cell deficiency is a consequence of defective c-Kit signalling. Staphylococcus aureus was injected intraperitoneally into mast-cell-deficient Mcpt5-Cre(+) x R-DTA mice using littermate mast-cell-sufficient mice as controls. We did not observe any difference between mast-cell-deficient and control mice with regard to weight loss, bacterial clearance, inflammation or cytokine production. We conclude that, despite peritoneal mast cells being activated by S. aureus in vitro, they do not influence the in vivo manifestations of intraperitoneal S. aureus infection.
|
|
| 23. |
- Spirkovski, Jane, et al.
(author)
-
M-OP-022 Mast cell apoptosis induced by siramesine, a sigma-2 receptor agonist
- 2012
-
Conference paper (other academic/artistic)abstract
- Mast cells (MCs) are well known for their detrimental effects in the context of allergic disorders. Strategies that limit MC function can therefore have a therapeutic value. Previous studies have shown that siramesine, a sigma-2 receptor agonist originally developed as an anti-depressant, can induce cell death in transformed cells through a mechanism involving lysosomal destabilization. Since MCs are remarkably rich in lysosome-like secretory granules we reasoned that MCs might be sensitive to siramesine. Here we show that murine and human MCs are highly sensitive to siramesine. Cell death was accompanied by secretory granule permeabilization, as shown by reduced acridine orange staining and leakage of granule proteases into the cytosol. Wild type siramesine-treated MCs underwent cell death with typical signs of apoptosis but MCs lacking serglycin, a proteoglycan crucial for promoting the storage of proteases within MC secretory granules, died predominantly by necrosis. A dissection of the underlying mechanism suggested that the necrotic phenotype of serglycin-/- cells was linked to defective Poly(ADP-ribose) polymerase-1 degradation. In vivo, siramesine treatment of mice caused a depletion of the MC populations of the peritoneum and skin. The present study shows for the first time that MCs are highly sensitive to apoptosis induced by siramesine and introduces the possibility of using siramesine as a therapeutic agent for treatment of MC-dependent disease.
|
|
| 24. |
- Tauber, Marie, et al.
(author)
-
Landscape of mast cell populations across organs in mice and humans
- 2023
-
In: Journal of Experimental Medicine. - : ROCKEFELLER UNIV PRESS. - 0022-1007 .- 1540-9538. ; 220:10
-
Journal article (peer-reviewed)abstract
- Mast cells (MCs) are tissue-resident immune cells that exhibit homeostatic and neuron-associated functions. Here, we combined whole-tissue imaging and single-cell RNA sequencing datasets to generate a pan-organ analysis of MCs in mice and humans at steady state. In mice, we identify two mutually exclusive MC populations, MrgprB2(+) connective tissue-type MCs and MrgprB2(neg) mucosal-type MCs, with specific transcriptomic core signatures. While MrgprB2(+) MCs develop in utero independently of the bone marrow, MrgprB2(neg) MCs develop after birth and are renewed by bone marrow progenitors. In humans, we unbiasedly identify seven MC subsets (MC1-7) distributed across 12 organs with different transcriptomic core signatures. MC1 are preferentially enriched in the bladder, MC2 in the lungs, and MC4, MC6, and MC7 in the skin. Conversely, MC3 and MC5 are shared by most organs but not skin. This comprehensive analysis offers valuable insights into the natural diversity of MC subtypes in both mice and humans. Combining whole-tissue imaging and single-cell RNA sequencing datasets, Tauber et al. present a pan-organ analysis of mast cells in mice and humans at steady state, revealing an unexpected heterogeneity of mast cell populations across tissues and species.
|
|
| 25. |
- von Beek, Christopher, et al.
(author)
-
Dynamin inhibition causes context-dependent cell death of leukemia and lymphoma cells
- 2021
-
In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 16:9
-
Journal article (peer-reviewed)abstract
- Current chemotherapy for treatment of pediatric acute leukemia, although generally successful, is still a matter of concern due to treatment resistance, relapses and life-long side effects for a subset of patients. Inhibition of dynamin, a GTPase involved in clathrin-mediated endocytosis and regulation of the cell cycle, has been proposed as a potential anti-cancer regimen, but the effects of dynamin inhibition on leukemia cells has not been extensively addressed. Here we adopted single cell and whole-population analysis by flow cytometry and live imaging, to assess the effect of dynamin inhibition (Dynasore, Dyngo-4a, MitMAB) on pediatric acute leukemia cell lines (CCRF-CEM and THP-1), human bone marrow biopsies from patients diagnosed with acute lymphoblastic leukemia (ALL), as well as in a model of lymphoma (EL4)-induced tumor growth in mice. All inhibitors suppressed proliferation and induced pronounced caspase-dependent apoptotic cell death in CCRF-CEM and THP-1 cell lines. However, the inhibitors showed no effect on bone marrow biopsies, and did not prevent EL4-induced tumor formation in mice. We conclude that dynamin inhibition affects highly proliferating human leukemia cells. These findings form a basis for evaluation of the potential, and constraints, of employing dynamin inhibition in treatment strategies against leukemia and other malignancies.
|
|
| 26. |
- Vraila, Marianthi, et al.
(author)
-
Monensin induces secretory granule-mediated cell death in eosinophils
- 2023
-
In: Journal of Allergy and Clinical Immunology. - : Elsevier. - 0091-6749 .- 1097-6825. ; 152:5
-
Journal article (peer-reviewed)abstract
- Background: Eosinophils contribute to the pathology of several types of disorders, in particular of allergic nature, and strategies to limit their actions are therefore warranted.Objective: We sought to evaluate the possibility of targeting the acidic, lysosome-like eosinophil granules as a potential means of inducing eosinophil cell death.Methods: To this end, we used monensin, an ionophoric drug that has previously been shown to permeabilize the secretory granules of mast cells, thereby inducing cell death.Results: Our findings reveal that monensin induces cell death in human eosinophils, whereas neutrophils were less affected. Blockade of granule acidification reduced the effect of monensin on the eosinophils, demonstrating that granule acidity is an important factor in the mechanism of cell death. Furthermore, monensin caused an elevation of the granule pH, which was accompanied by a decrease of the cytosolic pH, hence indicating that monensin caused leakage of acidic contents from the granules into the cytosol. In agreement with a granule-targeting mechanism, transmission electron microscopy analysis revealed that monensin caused extensive morphological alterations of the eosinophil granules, as manifested by a marked loss of electron density. Eosinophil cell death in response to monensin was caspase-independent, but dependent on granzyme B, a pro-apoptotic serine protease known to be expressed by eosinophils.Conclusions: We conclude that monensin causes cell death of human eosinophils through a granule-mediated mechanism dependent on granzyme B.
|
|
| 27. |
- Wensman, Helena, et al.
(author)
-
Tumor-mast cell interactions: Induction of pro-tumorigenic genes and anti-tumorigenic 4-1BB in MCs in response to Lewis Lung Carcinoma
- 2012
-
In: Molecular Immunology. - : Elsevier BV. - 0161-5890 .- 1872-9142. ; 50, s. 210-219
-
Journal article (peer-reviewed)abstract
- Mast cells (MCs) can have either detrimental or beneficial effects on malignant processes but the underlying mechanisms are poorly understood. Here we addressed this issue by examining the interaction between Lewis Lung Carcinoma (LLC) cells and MCs. In vivo, LLC tumors caused a profound accumulation of MCs, suggesting that LLC tumors have the capacity to attract MCs. Indeed, transwell migration assays showed that LLC-conditioned medium had chemotactic activity towards MCs, which was blocked by an antibody towards stem cell factor. In order to gain insight into the molecular mechanisms operative in tumor-MC interactions, the effect of LLC on the MC gene expression pattern was examined. As judged by gene array analysis, conditioned medium from LLC cells caused significant upregulation of numerous cell surface receptors and a pro-angiogenic Runx2/VEGF/Dusp5 axis in MCs, the latter in line with a role for MCs in promoting tumor angiogenesis. Among the genes showing the highest extent of upregulation was Tnfrsf9, encoding the anti-tumorigenic protein 4-1BB. suggesting that also anti-tumorigenic factors are induced. Quantitative RT-PCR analysis showed that 4-1BB was upregulated in a transient manner, and it was also shown that tumor cells induce 4-1BB in human MCs. Immunohistochemical analysis showed that LLC-conditioned medium induced 4-1BB also at the protein level. Together, this study provides novel insight into the molecular events associated with MC-tumor interactions and suggests that tumor cells induce both pro- and anti-tumorigenic responses in MCs. (C) 2012 Elsevier Ltd. All rights reserved.
|
|
| 28. |
- Öhrvik, Helena, et al.
(author)
-
Mast cells promote melanoma colonization of lungs
- 2016
-
In: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 7:42, s. 68990-69001
-
Journal article (peer-reviewed)abstract
- Mast cells have been implicated in malignant processes, mainly through clinical correlative studies and by experiments performed using animals lacking mast cells due to defective c-kit signaling. However, mast cell-deficient mouse models based on c-kit defects have recently been questioned for their relevance. Here we addressed the effect of mast cells in a tumor setting by using transgenic Mcpt5-Cre(+) R-DTA(+) mice, in which the deficiency of mast cells is independent of c-kit defects. Melanoma cells (B16.F10) were administered either subcutaneously or intravenously into Mcpt5-Cre(+) R-DTA(+) mice or Mcpt5-Cre(-) R-DTA(+) littermate controls, followed by the assessment of formed tumors. In the subcutaneous model, mast cells were abundant in the tumor stroma of control mice but were absent in Mcpt5-Cre(+) R-DTA(+) mice. However, the absence of mast cells did not affect tumor size. In contrast, after intravenous administration of B16.F10 cells, melanoma colonization of the lungs was markedly reduced in Mcpt5-Cre(+) R-DTA(+) vs. Mcpt5-Cre(-) R-DTA(+) animals. Decreased melanoma colonization of the lungs in Mcpt5-Cre(+) R-DTA(+) animals was accompanied by increased inflammatory cell recruitment into the bronchoalveolar lavage fluid, suggesting that mast cells suppress inflammation in this setting. Further, qPCR analysis revealed significant alterations in the expression of Twist and E-cadherin in lungs of Mcpt5-Cre(+) R-DTA(+) vs. control Mcpt5-Cre(-) R-DTA(+) animals, suggesting an impact of mast cells on epithelial-mesenchymal transition. In conclusion, this study reveals that mast cells promote melanoma colonization of the lung.
|
|
