scholarly journals The role of mast cells in bone marrow diseases

2004 ◽  
Vol 57 (1) ◽  
pp. 108-a-109 ◽  
Author(s):  
O Ozdemir
Keyword(s):  
Bone Marrow ◽  
Mast Cells ◽  
Bone Marrow Diseases

Role of common cytokine receptor γ chain (γc)– and Jak3-dependent signaling in the proliferation and survival of murine mast cells

Blood ◽  
2000 ◽  
Vol 96 (6) ◽  
pp. 2172-2180 ◽  
Author(s):  
Kotaro Suzuki ◽  
Hiroshi Nakajima ◽  
Norihiko Watanabe ◽  
Shin-ichiro Kagami ◽  
Akira Suto ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mast Cells ◽  
Cytokine Receptor ◽  
Type I ◽  
Dependent Manner ◽  
Type Ii ◽  
Wild Type ◽  
Peritoneal Mast Cells ◽  
The Common

Abstract The regulatory roles of the common cytokine receptor γ chain (γc)– and Jak3-dependent signaling in the proliferation and survival of mast cells were determined using γc-deficient (γc−) and Jak3-deficient (Jak3−) mice. Although the mast cells in γc− and Jak3− mice were morphologically indistinguishable from those in wild-type mice, the number of peritoneal mast cells was decreased in γc− and Jak3− mice as compared with that in wild-type mice. Among γc-related cytokines, interleukin (IL)-4 and IL-9, but not IL-2, IL-7, or IL-15, enhanced the proliferation and survival of bone marrow–derived mast cells (BMMCs) from wild-type mice. However, the effects of IL-4 and IL-9 were absent in BMMCs from γc− and Jak3−mice. In addition, IL-4Rα, γc, and Jak3, but not IL-2Rβ or IL-7Rα, were expressed in BMMCs. In contrast, IL-13 did not significantly induce the proliferation and survival of BMMCs even from wild-type mice, and IL-13Rα1 was not expressed in BMMCs. Furthermore, IL-4 phosphorylated the 65-kd isoform of Stat6 in BMMCs from wild-type mice but not from γc− and Jak3− mice. These results indicate that γc- and Jak3-dependent signaling is essential for IL-4– and IL-9–induced proliferation and survival of murine mast cells, that the effects of IL-4 are mediated by type I IL-4R and that type II IL-4R is absent on mast cells, and that IL-4 phosphorylates the 65-kd isoform of Stat6 in mast cells in a γc- and Jak3-dependent manner.

scholarly journals The Four Distal Tyrosines Are Required for LAT-dependent Signaling in FcεRI-mediated Mast Cell Activation

2003 ◽  
Vol 198 (5) ◽  
pp. 831-843 ◽  
Author(s):  
Shin-ichiroh Saitoh ◽  
Sandra Odom ◽  
Gregorio Gomez ◽  
Connie L. Sommers ◽  
Howard A. Young ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mast Cell ◽  
Mast Cells ◽  
Phospholipase C ◽  
Cell Activation ◽  
Genetically Modified ◽  
Adaptor Protein ◽  
Retroviral Vectors ◽  
Mast Cell Activation

The linker for activation of T cells (LAT) is an adaptor protein critical for FcεRI-mediated mast cell activation. LAT is a substrate of the tyrosine kinases activated after TCR and FcεRI engagement. After phosphorylation of the cytosolic domain of LAT, multiple signaling molecules such as phospholipase C–γ1, Grb2, and Gads associate with phosphorylated LAT via their SH2 domains. The essential role of the four distal tyrosines in TCR-mediated signaling and T cell development has been demonstrated by experiments using LAT-deficient cell lines and genetically modified mice. To investigate the role of these four tyrosines of LAT in FcεRI-mediated mast cell activation, bone marrow–derived mast cells from LAT-deficient mice were infected with retroviral vectors designed to express wild-type or mutant LAT. Examination of bone marrow–derived mast cells expressing various tyrosine to phenylalanine mutants in LAT demonstrates a differential requirement for these different binding sites. In these studies, assays of biochemical pathways, degranulation, and cytokine and chemokine release were performed. Finally, the role of these tyrosines was also evaluated in vivo using genetically modified animals. Deletion of all four distal tyrosines, and in particular, loss of the primary phospholipase C–γ-binding tyrosine had a significant effect on antigen-induced histamine release.

ROCKI Regulates Growth, Maturation and Migration of Mast Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2191-2191
Author(s):  
Veerendra Munugalavadla ◽  
Emily Sims ◽  
Jianjian Shi ◽  
Lei Wei ◽  
Reuben Kapur
Keyword(s):  
Bone Marrow ◽  
Mast Cell ◽  
Mast Cells ◽  
Cell Growth ◽  
Cell Activation ◽  
Critical Role ◽  
Hematopoietic Cells ◽  
Mast Cell Activation ◽  
Tyrosine Kinase Receptor

Abstract Mast cell activation plays a critical pathophysiologic role in asthma and allergy. A role for mast cell activation has also been described in multiple sclerosis, rheumatoid arthritis and coronary artery disease. In addition, these cells also play a prominent role in early phases of innate immunity to pathogenic bacteria. While several cytokines influence the growth, survival and maturation of mast cells; stem cell factor (SCF) and its interaction via the tyrosine kinase receptor, KIT is essential for normal mast cell development and function. However the intracellular signals that control mast cell growth, migration and maturation are not completely understood. In non-hematopoietic cells, Rho family GTPases are key regulators of many different biological processes including cell motility, growth, and differentiation. Cdc42, Rac and Rho are the most extensively studied members of this family. Although the role of Rac GTPases is becoming increasingly clear in mast cells and in hematopoietic cells in general, virtually nothing is known about the role of downstream effectors of Rho GTPases in these cells. RhoA and RhoC activate the serine/threonine protein kinases ROCKI and ROCKII. We show that both ROCKI and ROCKII are expressed in hematopoietic cells, including in bone marrow cells, splenocytes as well as in thymocytes. To determine the role of ROCK kinases in mast cells, we generated mice deficient in the expression of ROCKI. Here, we demonstrate that Rho-kinase ROCKI plays an essential role in regulating mast cell growth and maturation. We show that deficiency of ROCKI results in impaired maturation of bone marrow derived mast cells in response to IL-3 stimulation. Furthermore, the reduced maturation of ROCKI−/− mast cells is associated with reduced expression of KIT as well as reduced expression of the high affinity receptor for IgE at different stages of maturation (13% vs 7% at week1, 80% vs 52% at week2, and 93% vs 67% KIT/IgE receptor double positive cells at week3, n=3). KIT induced proliferation in response to SCF was also significantly reduced in ROCKI deficient mast cells, which was associated with reduced activation of MAPKinase Erk1 and Erk2. To test if the decreased growth in response to SCF was simply due to reduced KIT expression or due to cell intrinsic defects in ROCKI signaling, we isolated KIT positive WT and ROCKI−/− mast cells and measured growth in response to SCF and/or IL-3 stimulation by thymidine incorporation over a period of 24 and 48 hours. KIT positive ROCKI−/− mast cells showed reduced growth in response to SCF as well as in response to a combination of SCF and IL-3, suggesting a critical role of ROCKI in normal growth and maturation of mast cells. Since ROCK kinases also regulate migration in non-hematopoietic cells, we next examined the role of ROCKI in integrin (haptotactic) as well as in cytokine induced (chemotaxis) migration of mast cells. Mast cells deficient in ROCKI showed a 68% reduction in directional migration on fibronectin alone (64±7 [WT] vs 20±4, p<0.05) and a 31% reduction in the presence of SCF and fibronectin (181±16 [WT] vs 124±11 [ROCK1−/−], p<0.05), although no defects in SCF induced chemotaxis were observed. Taken together, our results identify ROCKI as a novel molecule that regulates growth, maturation and integrin-directed (haptotactic) migration of mast cells. Our results suggest that commercially available ROCK kinase inhibitors could prove to be useful small molecule inhibitors for treating diseases involving mast cells such as chronic inflammation and allergy.

scholarly journals Changes in Activated Bone Marrow Macrophages and Mast Cells in Patients with Myelofibrosis Following Ruxolitinib Therapy

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3184-3184 ◽  
Author(s):  
Hans Michael Kvasnicka ◽  
Juergen Thiele ◽  
Carlos E. Bueso-Ramos ◽  
Shilpa Kamalanabhaiah ◽  
Jorge E. Cortes ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mast Cells ◽  
Research Funding ◽  
Statistical Significance ◽  
Tnf Alpha ◽  
Spleen Size ◽  
Who Grade ◽  
Expression Levels ◽  
Anti Inflammatory

Abstract Background: Macrophages (MAC) are key regulators of malignant progression in solid tumors by promoting tumor cell invasion, migration and angiogenesis. Only few studies have investigated the role of activated MAC phenotypes, such as M1 and M2, in the bone marrow (BM) microenvironment of myelofibrosis (MF). MAC are generally increased in the BM of patients (pts) with MF and recent studies have also identified mast cells (MC) as playing an important role in regulating the underlying inflammatory process in MF. With regard to the substantial improvement in the mostly cytokine-driven constitutional symptoms following JAK inhibition therapy, we have investigated the effect of ruxolitinib (RUX) on BM MAC subtypes and MC and their association with BM fibrosis. Methods: A total of 63 pts with high-risk MF were included in this analysis. All pts had both baseline (BL) and sequential BM trephine biopsy at 24 months (mo) following RUX therapy. Using specific immunohistochemical stains, we analyzed assorted MAC markers, including CD68 and CD163. CD68 is a pan-MAC marker that recognizes both M1 and anti-inflammatory M2 subtypes. CD163 is a scavenger receptor upregulated by MAC within an anti-inflammatory environment and regarded as a highly specific monocyte/macrophage marker for the M2 subtype. Anti-Mast Cell Tryptase was applied as specific antibody to identify BM MC. All sections were stained following routine procedures and quantification of positivity was performed for each marker by consensus after independent review by 3 pathologists. Cytokine expression levels (TNF-alpha, MIP-1-alpha, IgE) at week 4 and 24 mo following RUX therapy were available for a subset of 23 and 16 pts. Individual changes were categorized as increase, stable, or decrease and correlated to the degree of WHO BM fibrosis grade and hematological features. Results: At BL, 81.0% of MF pts presented with an advanced fibrotic stage of disease (WHO grade 2 or 3). Grade of BM fibrosis significantly correlated with the frequency of CD68+ and CD168+ MAC. Furthermore, advanced fibrosis was associated with a higher frequency of BM MC. Following RUX treatment, 14.3% of cases showed an improvement in BM fibrosis, while 58.7% showed stabilization. RUX induced in 48.3% of cases a significant decrease in the overall amount of BM CD68+ MAC, whereas a further increase was observed in only 6.9%. Similar results were obtained for the specific CD163+ anti-inflammatory M2 subtype. Post-RUX a significant reduction of this cell lineage was seen in 47.6%, while 12.7% of cases revealed a further increase. Improvement in BM fibrosis was highly correlated with an overall reduction of CD68+ MAC, and in particular with modulation of the CD163+ M2 subtype. RUX therapy induced a profound reduction in the expression of associated cytokines such as TNF-alpha and MIP-1-alpha, both at 4 weeks and 24 mo. Frequency of BM MC was reduced in 26.3% of pts during therapy, however, in 49.1% therapy showed no change. Pts with improvement in BM fibrosis revealed in most cases lower frequencies of MC, but this association did not reach statistical significance. In contrast, expression levels of IgE were strongly reduced in almost all pts at week 4 and 24 mo. The amount of MAC or MC did not correlate with BL hematological or clinical parameters such as BL spleen size, anemia or platelet counts. Following RUX, decreases in M1 and M2 MAC were associated with changes in hemoglobin levels and spleen size reduction. Conclusions: Our results significantly extend previous observations on the role of the BM microenvironment in MF. RUX treatment meaningfully and directionally impacts the amount of activated anti-inflammatory MAC in BM of MF patients. Overall, our data advocate the strong disease modulation capacity of anti-JAK therapy. Disclosures Kvasnicka: Novartis: Consultancy, Honoraria, Research Funding; Incyte Corporation: Consultancy, Honoraria. Thiele:Novartis: Consultancy, Honoraria; Incyte Corporation: Consultancy, Honoraria. Kantarjian:Novartis: Research Funding. Verstovsek:NS Pharma, Inc: Research Funding.

Mast Cells Are Integral Components of the Tumor Microenvironment That Are Required for Plexiform Neurofibroma Progression.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 677-677
Author(s):  
Fengchun Yang ◽  
David A. Ingram ◽  
Shi Chen ◽  
Jin Yuan ◽  
Xiaohong Li ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mast Cell ◽  
Mast Cells ◽  
Tumor Microenvironment ◽  
Tumor Progression ◽  
Schwann Cells ◽  
Plexiform Neurofibroma ◽  
Hematopoietic System ◽  
Plexiform Neurofibromas

Abstract Interactions between tumorigenic cells and the microenvironment are increasingly recognized as integral to tumor progression in a range of human malignancies. However, the specific cellular mechanisms that are required to initiate these multistage processes are incompletely understood. Mutations in the NF1 tumor suppressor gene cause neurofibromatosis type 1, a pandemic autosomal dominant genetic disorder of the nervous system characterized by the development of neurofibromas. Neurofibromas are complex tumors composed of Schwann cells, fibroblasts, endothelial cells, and high concentrations of degranulating mast cells. Though neurofibromas are generally benign, plexiform neurofibromas can progress to malignancy. Genetic studies in cre/lox mice indicate that nullizygous loss of Nf1 in the tumorigenic Schwann cells (Krox20; Nf1flox/flox) is necessary, but not sufficient for neurofibroma formation when the microenvironment is wildtype. However, neurofibromas form with 100% penetrance in Krox20; Nf1flox/− mice that are heterozygous at Nf1 in all lineages of the tumor microenvironment (Science, 2002). Here, we addressed the role of the hematopoietic system in the tumor microenvironment by using adoptive transfer. Syngeneic Nf1+/− or wildtype (WT) bone marrow was transplanted into lethally irradiated Krox20;Nf1flox/flox mice. Krox20; Nf1flox/flox recipients transplanted with WT bone marrow (n=25) did not develop plexiform neurofibromas and had a normal lifespan. In contrast, Krox20; Nf1flox/flox mice transplanted with Nf1+/− bone marrow (n=25) consistently developed neurofibromas infiltrated with Nf1+/− mast cells. These mice had a 90% mortality at 14 months following transplantation. In complementary experiments, WT bone marrow was transplanted into irradiated Krox20; Nf1flox/− mice. Despite the remainder of the tumor microenvironment being heterozygous, WT bone marrow was sufficient to prevent tumor progression in Krox20; Nf1flox/− mice. To specifically assess the role of the mast cell compartment in tumor progression, Nf1+/− mice were intercrossed with two strains of naturally occurring W mutant mice that have variably diminished c-kit activity and mast cell function. Mice homozygous at the Wv locus have a greater than 90% reduction in c-kit activity, while W41/W41 mutants have approximately a 65–75% reduction in c-kit activity. Importantly, while Krox20;Nf1flox/flox mice transplanted with Nf1+/− bone marrow consistently develop plexiform neurofibromas, adoptive transfer of Nf1+/−; Wv/Wv or Nf1+/−; W41/W41 bone marrow cells into Krox20; Nf1flox/flox mice was sufficient to prevent neurofibroma formation. Collectively, these studies provide genetic evidence that the hematopoietic system and specifically mast cells are integral to plexiform neurofibroma formation in genetically engineered mice. These studies have therapeutic implications for NF1 since molecular therapies directed at the haploinsufficient hematopoietic cells, particularly the c-kit receptor tyrosine kinase, may have an important role in treating or preventing plexiform neurofibromas.

Identification of Oncostatin M as a Novel KIT D816V-Dependent Cytokine in Neoplastic Human Mast Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 213-213
Author(s):  
Gregor Hoermann ◽  
Sabine Cerny-Reiterer ◽  
Andrea Perne ◽  
Miriam Klauser ◽  
Leonhard Muellauer ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mast Cell ◽  
Mast Cells ◽  
Dominant Negative ◽  
Oncostatin M ◽  
Mitogen Activated Protein Kinase ◽  
Affect Expression ◽  
Mitogen Activated Protein ◽  
Kit D816v

Abstract Abstract 213 Systemic mastocytosis (SM) is a neoplastic disease of mast cells (MC) and their bone marrow-derived progenitors. The clinical picture in SM is variable ranging from an indolent course to highly aggressive variants with short survival time. The pathologic hallmark in SM is the multifocal dense infiltrate of MC in the bone marrow. Other typical features of SM include alterations of the bone marrow microenvironment such as increased angiogenesis and fibrosis. In a majority of patients, MC display the KIT mutation D816V which affects the activation loop at the entrance to the enzymatic pocket of the KIT kinase. As a consequence, KIT D816V exhibits constitutive tyrosine kinase activity and promotes cytokine-independent differentiation of MC. However, so far, little is known about KIT D816V-dependent expression of pathogenetically relevant molecules in neoplastic MC. Oncostatin M (OSM) is a pleiotropic cytokine of the interleukin-6 family which is produced mainly by activated T cells and monocytes. OSM has been shown to inhibit cell growth in cell lines derived from solid tumors but to stimulate proliferation of fibroblasts and endothelial cells. Recently, it has been reported that OSM produced by activated MC promotes growth of human dermal fibroblasts. Moreover, it has been suggested that OSM stimulates growth of murine bone marrow-derived mast cells in a mast cell/fibroblast coculture. However, expression of OSM in neoplastic MC or a potential pathogenetic role of OSM in SM have not been examined so far. The aim of the present study was to analyze expression of OSM in neoplastic human MC and to determine the role of KIT D816V in OSM expression. As assessed by immunohistochemistry performed on bone marrow sections of patients with SM, typical spindle-shaped neoplastic MC were found to express OSM. Serial section-staining confirmed that tryptase-positive MC co-express OSM. Expression of OSM was found in neoplastic MC in all patients investigated (n=15) and in all variants of SM (indolent SM as well as aggressive variants) with comparable staining intensities. Preincubation of anti-OSM antibody with a specific blocking peptide resulted in a negative stain. In Ba/F3 cells, doxycycline-inducible expression of KIT D816V led to a substantial upregulation of OSM mRNA and OSM protein, whereas expression of wild type KIT did not affect expression of OSM. In addition, the KIT D816V-positive HMC-1.2 mast cell line was found to express OSM at high levels, whereas the KIT D816V-negative HMC-1.1 subclone expressed only baseline levels of OSM. Correspondingly, the KIT D816V-targeting drug midostaurine (PKC412) decreased the expression of OSM in HMC-1.2 cells as well as in KIT D816V-expressing Ba/F3 cells in a dose-dependent manner. To investigate signaling pathways involved in KIT D816V-dependent expression of OSM, we applied pharmacologic inhibitors and dominant negative-acting signaling molecules. We found that KIT D816V-dependent expression of OSM is inhibited by the mitogen-activated protein-kinase/extracellular signal-regulated kinase (MEK) inhibitor, PD98059, but not by the phosphoinositide 3-kinase inhibitor, LY294002. Expression of dominant negative mutants of signal transducer and activator of transcription 5 (STAT5) did not affect expression of OSM in KIT D816V-expressing cells. In summary, our data identify OSM as a novel cytokine expressed in neoplastic MC in patients with SM and show that KIT D816V directly promotes expression of OSM through activation of the mitogen-activated protein-kinase pathway. OSM may be an important KIT D816V-dependent effector promoting angiogenesis and fibrogenesis/sclerosis in patients with SM. Disclosures: No relevant conflicts of interest to declare.

Role of common cytokine receptor γ chain (γc)– and Jak3-dependent signaling in the proliferation and survival of murine mast cells

Blood ◽  
2000 ◽  
Vol 96 (6) ◽  
pp. 2172-2180
Author(s):  
Kotaro Suzuki ◽  
Hiroshi Nakajima ◽  
Norihiko Watanabe ◽  
Shin-ichiro Kagami ◽  
Akira Suto ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Mast Cells ◽  
Cytokine Receptor ◽  
Type I ◽  
Dependent Manner ◽  
Type Ii ◽  
Wild Type ◽  
Peritoneal Mast Cells ◽  
The Common

The regulatory roles of the common cytokine receptor γ chain (γc)– and Jak3-dependent signaling in the proliferation and survival of mast cells were determined using γc-deficient (γc−) and Jak3-deficient (Jak3−) mice. Although the mast cells in γc− and Jak3− mice were morphologically indistinguishable from those in wild-type mice, the number of peritoneal mast cells was decreased in γc− and Jak3− mice as compared with that in wild-type mice. Among γc-related cytokines, interleukin (IL)-4 and IL-9, but not IL-2, IL-7, or IL-15, enhanced the proliferation and survival of bone marrow–derived mast cells (BMMCs) from wild-type mice. However, the effects of IL-4 and IL-9 were absent in BMMCs from γc− and Jak3−mice. In addition, IL-4Rα, γc, and Jak3, but not IL-2Rβ or IL-7Rα, were expressed in BMMCs. In contrast, IL-13 did not significantly induce the proliferation and survival of BMMCs even from wild-type mice, and IL-13Rα1 was not expressed in BMMCs. Furthermore, IL-4 phosphorylated the 65-kd isoform of Stat6 in BMMCs from wild-type mice but not from γc− and Jak3− mice. These results indicate that γc- and Jak3-dependent signaling is essential for IL-4– and IL-9–induced proliferation and survival of murine mast cells, that the effects of IL-4 are mediated by type I IL-4R and that type II IL-4R is absent on mast cells, and that IL-4 phosphorylates the 65-kd isoform of Stat6 in mast cells in a γc- and Jak3-dependent manner.

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