1.
von Beek, Christopher, et al.
(författare)
A two-step activation mechanism enables mast cells to differentiate their response between extracellular and invasive enterobacterial infection
2024
Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 15:1
Tidskriftsartikel (refereegranskat) abstract
Mast cells localize to mucosal tissues and contribute to innate immune defense against infection. How mast cells sense, differentiate between, and respond to bacterial pathogens remains a topic of ongoing debate. Using the prototype enteropathogen Salmonella Typhimurium (S.Tm) and other related enterobacteria, here we show that mast cells can regulate their cytokine secretion response to distinguish between extracellular and invasive bacterial infection. Tissue-invasive S.Tm and mast cells colocalize in the mouse gut during acute Salmonella infection. Toll-like Receptor 4 (TLR4) sensing of extracellular S.Tm, or pure lipopolysaccharide, causes a modest induction of cytokine transcripts and proteins, including IL-6, IL-13, and TNF. By contrast, type-III-secretion-system-1 (TTSS-1)-dependent S.Tm invasion of both mouse and human mast cells triggers rapid and potent inflammatory gene expression and >100-fold elevated cytokine secretion. The S.Tm TTSS-1 effectors SopB, SopE, and SopE2 here elicit a second activation signal, including Akt phosphorylation downstream of effector translocation, which combines with TLR activation to drive the full-blown mast cell response. Supernatants from S.Tm-infected mast cells boost macrophage survival and maturation from bone-marrow progenitors. Taken together, this study shows that mast cells can differentiate between extracellular and host-cell invasive enterobacteria via a two-step activation mechanism and tune their inflammatory output accordingly.
2.
Põlajeva, Jelena, et al.
(författare)
Glioma-derived macrophage migration inhibitory factor (MIF) promotes mast cell recruitment in a STAT5-dependent manner
2014
Ingår i: Molecular Oncology. - : Wiley. - 1574-7891 .- 1878-0261. ; 8:1, s. 50-58
Tidskriftsartikel (refereegranskat) abstract
Recently, glioma research has increased its focus on the diverse types of cells present in brain tumors. We observed previously that gliomas are associated with a profound accumulation of mast cells (MCs) and here we investigate the underlying mechanism. Gliomas express a plethora of chemoattractants. First, we demonstrated pronounced migration of human MCs toward conditioned medium from cultures of glioma cell lines. Subsequent cytokine array analyses of media from cells, cultured in either serum-containing or -free conditions, revealed a number of candidates which were secreted in high amounts in both cell lines. Among these, we then focused on macrophage migration inhibitory factor (MIF), which has been reported to be pro-inflammatory and -tumorigenic. Infiltration of MCs was attenuated by antibodies that neutralized MIF. Moreover, a positive correlation between the number of MCs and the level of MIF in a large cohort of human glioma tissue samples was observed. Further, both glioma-conditioned media and purified MIF promoted differential phosphorylation of a number of signaling molecules, including signal transducer and activator of transcription 5 (STAT5), in MCs. Inhibition of pSTAT5 signaling significantly attenuated the migration of MCs toward glioma cell-conditioned medium shown to contain MIF. In addition, analysis of tissue microarrays (TMAs) of high-grade gliomas revealed a direct correlation between the level of pSTAT5 in MCs and the level of MIF in the medium. In conclusion, these findings indicate the important influence of signaling cascades involving MIF and STAT5 on the recruitment of MCs to gliomas.
3.
Alim, Abdul, 1983-
(författare)
Mechanisms in Tendon Healing : Pain, Biomarkers and the Role of Mast Cells
2019
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Tendon injuries and tendinopathy are common disorders, but the underlying mechanisms are not well understood. The overall aim of this thesis was to better understand the mechanisms underlying tendon healing, pain, and inflammation.The aim of the first study was to assess biomarkers of tendon healing, including procollagen type I (PINP) and type III (PIIINP) in relation to patient outcome in 65 patients with Achilles tendon rupture (ATR). At two weeks post-ATR, PINP and PIIINP-levels were quantified using microdialysis followed by ELISA. At one-year post-ATR patient outcome was assessed using the validated Achilles tendon Total Rupture Score. We found that higher ratio of PINP and PIIINP to total protein were significantly associated with less pain but more fatigue in the affected limb.In the second study, we applied Intermittent Pneumatic Compression (IPC) therapy for two weeks to stimulate tendon healing. The patients received either adjuvant IPC treatment or treatment-as-usual in a plaster cast without IPC. We observed that IPC therapy significantly increased PINP levels in the injured tendon, suggesting enhanced healing response.In our third study, we investigated healing response and the role of mast cells (MCs) in-vivo using an ATR rat model. Three weeks postoperatively, we demonstrated an increased number of MCs and a higher proportion of degranulated MCs in the injured tendon compared to the control. We further established that MCs in the injured tendon were positive for the glutamate receptor NMDAR1.In our final study, we assessed the effect of glutamate stimulation on in-vitro-derived mouse bone marrow MCs. Mast cell degranulation was quantified through β-hexosaminidase release, immunofluorescence was used to quantify NMDARs at the protein level, and RT-qPCR/microarray was used to study the expression of NMDARs and associated genes. Glutamate induced a robust upregulation of glutamate receptors of both ionotropic and metabotropic type, both at the mRNA and at protein level. NMDAR1 co-localized with glutamate in the membrane of MCs, thereby confirming an interaction between glutamate and its receptor. Glutamate also induced expression of pro-inflammatory compounds such as IL-6 and CCL2 and transcription factors such as Egr2, Egr3 and FosB. Moreover, the NMDA-channel blocker MK-801 completely abrogated the response of MCs to glutamate, supporting a functional glutamate–glutamate receptor axis in MCs.Together, findings presented in this dissertation reveal possible mechanisms of tendon healing in relation to pain and function, and establish a novel principle for how immune cells can communicate with nerve cells after ATR.
4.
Magnúsdóttir, Elín Ingibjörg, et al.
(författare)
Mouse mast cells and mast cell proteases do not play a significant role in acute tissue injury pain induced by formalin
2018
Ingår i: Molecular Pain. - : SAGE Publications. - 1744-8069. ; 14
Tidskriftsartikel (refereegranskat) 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.
5.
Frisk, Jun Mei Hu, et al.
(författare)
Mitogen-Activated Protein Kinase Signaling Regulates Proteoglycan Composition of Mast Cell Secretory Granules
2018
Ingår i: Frontiers in Immunology. - : FRONTIERS MEDIA SA. - 1664-3224. ; 9
Tidskriftsartikel (refereegranskat) abstract
Mast cells (MCs) are characterized by an abundance of lysosome-like secretory granules filled with immunomodulatory compounds including histamine, cytokines, lysosomal hydrolases, MC-restricted proteases, and serglycin proteoglycans. The latter are essential for promoting the storage of other granule compounds and are built up of the serglycin core protein to which highly sulfated and thereby negatively charged glycosaminoglycan (GAG) side chains of heparin or chondroitin sulfate type are attached. In the search for mechanisms operating in regulating MC granule homeostasis, we here investigated the role of mitogen-activated protein kinase (MAPK) signaling. We show that inhibition of MEK1/2 (a MAPK kinase) leads to increased metachromatic staining of MC granules, indicative of increased proteoglycan content. Indeed, MEK1/2 inhibition caused a profound increase in the expression of the gene coding for the serglycin core protein and of genes coding for various enzymes involved in the biosynthesis/sulfation of the GAGs attached to the serglycin core protein. This was accompanied by corresponding increases in the levels of the respective GAGs. Deletion of the serglycin core protein abrogated the induction of enzymes operative in proteoglycan synthesis, indicating that availability of the serglycin proteoglycan core protein has a regulatory function impacting on the expression of the various serglycin-modifying enzymes. MEK1/2 inhibition also caused a substantial increase in the expression of granule-localized, proteoglycan-binding proteases. Altogether, this study identifies a novel role for MAPK signaling in regulating the content of secretory granules in MCs.
6.
Garcia-Vilas, Javier A., et al.
(författare)
Damnacanthal inhibits IgE receptor-mediated activation of mast cells
2015
Ingår i: Molecular Immunology. - : Elsevier BV. - 0161-5890 .- 1872-9142. ; 65:1, s. 86-93
Tidskriftsartikel (refereegranskat) abstract
Damnacanthal, an anthraquinone obtained from the noni fruit (Morinda citrifolia L), has been described to possess anti-cancer and anti-inflammatory properties. Since mast cells are key players in various inflammatory conditions as well as in cancer, we considered the possibility that the biological actions of damnacanthal, at least partly, could be due to effects on mast cells. Many of the biological activities of mast cells are mediated by IgE receptor cross-linking, which results in degranulation with release of preformed granule mediators, as well as de nova synthesis and release of additional compounds. Here we show that damnacanthal has profound inhibitory activity on mast cell activation through this pathway. The release of the granule compounds beta-hexosaminidase and tryptase release was completely abrogated by damnacanthal at doses that were non-toxic to mast cells. In addition, damnacanthal inhibited activation-dependent pro-inflammatory gene induction, as well as cytokine/chemokine release in response to mast cell stimulation. The mechanism underlying damnacanthal inhibition was linked to impaired phosphorylation of Syk and Akt. Furthermore, damnacanthal inhibited mast cell activation in response to calcium ionophore A23187. Altogether, the data presented here demonstrate that damnacanthal inhibits mast cell activation induced by different stimuli and open a new window for the use of this compound as a mast cell stabilizer.
7.
Pejler, Gunnar
(författare)
The emerging role of mast cell proteases in asthma
2019
Ingår i: European Respiratory Journal. - 0903-1936 .- 1399-3003. ; 54
Tidskriftsartikel (refereegranskat) abstract
It is now well established that mast cells play a crucial role in asthma. This is supported by multiple lines of evidence, including both clinical studies and studies on mast cell-deficient mice. However, there is still only limited knowledge of the exact effector mechanism(s) by which mast cells influence asthma pathology. Mast cells contain large amounts of secretory granules, which are filled with a variety of bioactive compounds including histamine, cytokines, lysosomal hydrolases, serglycin proteoglycans and a number of mast cell-restricted proteases. When mast cells are activated, e.g. in response to IgE receptor crosslinking, the contents of their granules are released to the exterior and can cause a massive inflammatory reaction. The mast cell-restricted proteases include tryptases, chymases and carboxypeptidase A3, and these are expressed and stored at remarkably high levels. There is now emerging evidence supporting a prominent role of these enzymes in the pathology of asthma. Interestingly though, the role of the mast cell-restricted proteases is multifaceted, encompassing both protective and detrimental activities. Here, I review the current knowledge of how the mast cell-restricted proteases impact on asthma.
8.
Paivandy, Aida, et al.
(författare)
Induction of Human Lung Mast Cell Apoptosis by Granule Permeabilization : A Novel Approach for Targeting Mast Cells
2017
Ingår i: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 8
Tidskriftsartikel (refereegranskat) abstract
Mast cells are implicated as detrimental players in inflammatory lung diseases, particularly asthma. Mast cells respond to activating stimuli by releasing a wide panel of pro-inflammatory compounds that can contribute profoundly to the pathology, and there is currently an unmet need for strategies that efficiently ameliorate harmful effects of mast cells under such conditions. Here, we sought to evaluate a novel concept for targeting human lung mast cells, by assessing the possibility of selectively depleting the lung mast cells by induction of apoptosis. For this purpose, we used lysosomotropic agents, i.e., compounds that are known to permeabilize the secretory granules of mast cells, thereby releasing the contents of the granules into the cytosol. Either intact human lung tissue, purified human lung mast cells or mixed populations of human lung cells were incubated with the lysosomotropic agents mefloquine or siramesine, followed by measurement of apoptosis, reactive oxygen species (ROS) production, and release of cytokines. We show that human lung mast cells were highly susceptible to apoptosis induced by this strategy, whereas other cell populations of the lung were largely refractory. Moreover, we demonstrate that apoptosis induced by this mode is dependent on the production of ROS and that the treatment of lung tissue with lysosomotropic agents causes a decrease in the release of pathogenic cytokines. We conclude that selective apoptosis of human lung mast cells can be accomplished by administration of lysosomotropic agents, thus introducing the possibility of using such drugs as novel therapeutics in the treatment of inflammatory lung disorders such as asthma.
9.
Pejler, Gunnar
(författare)
Mast cells protect from post-traumatic spinal cord damage in mice by degrading inflammation-associated cytokines via mouse mast cell protease 4
2014
Ingår i: Neurobiology of Disease. - : Elsevier BV. - 0969-9961 .- 1095-953X. ; 62, s. 260-272
Tidskriftsartikel (refereegranskat) abstract
Mast cells (MCs) are found abundantly in the central nervous system and play a complex role in neuroinflammatory diseases such as multiple sclerosis and stroke. In the present study, we show that MC-deficient Kit(W-sh/W-sh) mice display significantly increased astrogliosis and T cell infiltration as well as significantly reduced functional recovery after spinal cord injury compared to wildtype mice. In addition, MC-deficient mice show significantly increased levels of MCP-1, TNF-alpha, IL-10 and IL-13 protein levels in the spinal cord. Mice deficient in mouse mast cell protease 4 (mMCP4), an MC-specific chymase, also showed increased MCP-1, IL-6 and IL-13 protein levels in spinal cord samples and a decreased functional outcome after spinal cord injury. A degradation assay using supernatant from MCs derived from either mMCP4(-/-) mice or controls revealed that mMCP4 cleaves MCP-1, IL-6, and IL-13 suggesting a protective role for MC proteases in neuroinflammation. These data show for the first time that MCs may be protective after spinal cord injury and that they may reduce CNS damage by degrading inflammation-associated cytoldnes via the MC-specific chymase mMCP4. (C) 2013 The Authors. Published by Elsevier Inc All rights reserved.
10.
Akula, Srinivas, et al.
(författare)
Quantitative In-Depth Analysis of the Mouse Mast Cell Transcriptome Reveals Organ-Specific Mast Cell Heterogeneity
2020
Ingår i: CELLS. - : MDPI. - 2073-4409. ; 9:1
Tidskriftsartikel (refereegranskat) abstract
Mast cells (MCs) are primarily resident hematopoietic tissue cells that are localized at external and internal surfaces of the body where they act in the first line of defense. MCs are found in all studied vertebrates and have also been identified in tunicates, an early chordate. To obtain a detailed insight into the biology of MCs, here we analyzed the transcriptome of MCs from different mouse organs by RNA-seq and PCR-based transcriptomics. We show that MCs at different tissue locations differ substantially in their levels of transcripts coding for the most abundant MC granule proteins, even within the connective tissue type, or mucosal MC niches. We also demonstrate that transcript levels for the major granule proteins, including the various MC-restricted proteases and the heparin core protein, can be several orders of magnitude higher than those coding for various surface receptors and enzymes involved in protease activation, as well as enzymes involved in the synthesis of heparin, histamine, leukotrienes, and prostaglandins. Interestingly, our analyses revealed an almost complete absence in MCs of transcripts coding for cytokines at baseline conditions, indicating that cytokines are primarily produced by activated MCs. Bone marrow-derived MCs (BMMCs) are often used as equivalents of tissue MCs. Here, we show that these cells differ substantially from tissue MCs with regard to their transcriptome. Notably, they showed a transcriptome indicative of relatively immature cells, both with respect to the expression of granule proteases and of various enzymes involved in the processing/synthesis of granule compounds, indicating that care should be taken when extrapolating findings from BMMCs to the in vivo function of tissue-resident MCs. Furthermore, the latter finding indicates that the development of fully mature tissue-resident MCs requires a cytokine milieu beyond what is needed for in vitro differentiation of BMMCs. Altogether, this study provides a comprehensive quantitative view of the transcriptome profile of MCs resident at different tissue locations that builds nicely on previous studies of both the mouse and human transcriptome, and form a solid base for future evolutionary studies of the role of MCs in vertebrate immunity.
