Nucleus Of Mast Cells Research Articles

A Critical Role for Na+/H+ Exchanger Regulatory Factor 1 in Modulating FcεRI-Mediated Mast Cell Activation.

Mast cells are tissue-resident immune cells that play pivotal roles in initiating and amplifying allergic/anaphylactic reactions in humans. Their activation occurs via multiple mechanisms, which include cross-linking of the IgE-bound, high-affinity IgE receptors (FcεRI) by allergens or Ags and the binding of anaphylatoxins such as C3a to its receptor, C3aR. We have previously demonstrated that the Na+/H+ exchanger regulatory factor 1 (NHERF1) promotes C3aR functions in human mast cells. In the current study, we show that NHERF1 regulates mast cell response following FcεRI stimulation. Specifically, intracellular Ca2+ mobilization, activation of the MAPKs (ERK1/2 and P38), and production of cytokines (IL-13 and IL-6) following exposure to IgE/Ag were significantly reduced in mast cells from NHERF1+/‒ mice. In agreement with our in vitro data, mast cell-mediated passive cutaneous anaphylaxis and passive systemic anaphylaxis were reduced in NHERF1+/‒ mice and mast cell-deficient KitW-sh/W-sh mice engrafted with NHERF1+/‒ mast cells. Mechanistically, the levels of microRNAs (miRNAs) that regulate mast cell responses, miRNA 155-3p and miRNA 155-5p, were altered in mast cells from NHERF1+/‒ mice. Moreover, NHERF1 rapidly localized to the nucleus of mast cells following FcεRI stimulation. In summary, our results suggest that the NHERF1 acts as an adapter molecule and promotes IgE/Ag-induced mast cell activation. Further elucidating the mechanisms through which NHERF1 modulates mast cell responses will lend insights into the development of new therapeutic strategies to target mast cells during anaphylaxis or other allergic diseases.

Estrogen is involved in hemangioma regression associated with mast cells

BackgroundEstrogen plays a role in infantile hemangioma (IH) development, but the underlying mechanism remains unclear. This study aimed to assess estrogen and estrogen receptor (ER) localization and expression levels in IH. In addition, the unexpected relationship between mast cells (MCs) and estrogen in human IH was discussed.MethodsIH (n = 29), vascular malformation (VMs, n = 33) and normal skin (n = 15) specimens were assessed. IH was classified into proliferative (n = 9; age, 3.56 ± 1.01 months), early involuting (n = 10; age, 8.90 ± 2.69 months) and late involuting (n = 10; age, 20.10 ± 4.93 months) groups. Estradiol (E2), ER-a, ER-β, and tryptase (MC marker) levels were determined immunohistochemically and/or by double immunofluorescence staining. Quantification and localization of tryptase, ER-a, and E2 were assessed for each specimen.ResultsER-a, E2, and tryptase were expressed in the cytoplasm and nucleus of MCs in IH. The IH specimens showed significantly more tryptase, ER-a, and E2 positive MCs (30.6 ± 12.7, 9.7 ± 5.6, and 19.8 ± 8.7 cells/high-power field [HPF], respectively) compared with VM specimens (9.0 ± 9.8, 1.5 ± 2.4, and 2.5 ± 4.1 cells/HPF, respectively) and normal skin (6.1 ± 8.5, 0.5 ± 1.2, and 1.9 ± 3.4 cells/HPF, respectively). Proliferating IH displayed fewer E2 positive MCs (14.0 6.3 cells/HPF) compared with early (22.3 ± 10.2 cells/HPF, P = 0.023) and late (22.4 ± 6.8 cells/HPF, P = 0.006) involuting specimens. In addition, proliferating IH showed fewer tryptase positive MCs (24.7 ± 10.8 cells/HPF) compared with early involuting specimens (35.7 ± 15.3 cells/HPF, P = 0.043). All IH specimens were ER-a positive and ER-β negative.ConclusionsE2 and ER-a are expressed on MCs and not on IH endothelial cells. Furthermore, activated MCs may be involved in IH regression.

The Immuno-Endocrine System: Hormones, Receptors and Endocrine Function of Immune Cells. The Packed-Transport Theory

Immune cells (lymphocytes, monocytes and macrophages, granulocytes and mast cells) produce numerous hormones, store and secrete them. In addition these cells have receptors for hormones and signal transduction pathways. These functions are under the control of the central nervous system (neuro-immune regulation), and there is a dynamic multi-directional interaction within the neuroimmune circuitry. Considering the high amount of immune cells, their hormone production can rival to that of the classical endocrine glands. However, in contrast to the endocrine glands, which are in general mono-producers, 1.) the immune cells are poly-producers, the same cell can produce different hormones at the same time and also poly-receivers, having receptors for different hormones, 2.) immune cells are mobile and can transport the hormones in a packaged form, even though they are able to synthesize and secrete the hormones locally. 3.) immune cells have the capacity to recognize the site where their hormones are needed. It is proposed that under the control of the nervous system immune cells produce hormones for general regulation, for intrasystem regulation and for remote, local regulation. Hormone production is gender dependent. Receptors are affected by hormonal imprinting during the critical developmental periods of target cells and the imprinting influences also the hormone synthesis of immune cells for life. Some hormones can be demonstrated in the nucleus of mast cells, however their function is not known. The knock-out of one hormone's gene disturbs hormone balance in immune cells. The importance of the packed-transport hypothesis is discussed.

Hormones in the Nucleus of Mast Cells: Confocal Microscopic Immunocytochemical Observations

In earlier experiments, the presence of histamine and serotonin in the nucleus of mast cells was demonstrated. At present we studied the presence or absence of four hormones: adrenocorticotropine (ACTH), growth hormone (GH), triiodothyronine (T(3)), and progesterone. Cells of the (adult female) rat peritoneal fluid were fixed by EDAC and studied by laser-scanning confocal microscope, after treatment with primary antibodies and FITC-labeled secondary antibody. Strong ACTH and growth hormone fluorescence can be seen in the nucleus. ACTH fluorescence is present also in the granules. The cytoplasm of lymphocytes contains both ACTH and GH. T(3) shows very pale fluorescence, and progesterone is negative. The conclusion is that the nucleus of mast cells contains two polypeptide hormones studied. This was demonstrated by using EDAC fixation as this is a cross-linking agent and does not allow the escape of the minute amounts of hormones from the nucleus. Earlier observations on peptide hormones' nuclear presence and their importance are discussed.

Serotonin content is elevated in the immune cells of histidine decarboxylase gene knock-out (HDCKO) mice. Focus on mast cells

Biogenic amines, histamine and serotonin are present in the granules and nucleus of mast cells. We wanted to study the presence, amount and localization of serotonin in mast cells and other cells of the immune system, under conditions of histamine deficiency caused by knock out of histamine decarboxylase gene (HDCKO). Wild type and histamine deficient HDCKO mice were studied for serotonin content of the immune cells (lymphocytes as well as the monocyte-granulocyte-mast cell group) using flow cytometry and confocal microscopy. Groups of mice were kept either on complete rodent chow or on a histamine-free diet for a month before the experiments. The amount of serotonin was significantly higher in the KO animals, irrespective of the diet. Confocal microscopy demonstrated the presence of serotonin in the nucleus of mast cells in the wild type animals, while it was not present in the KO mice. Furthermore, in the cytoplasm (granules) of KO mast cells a bright fluorescence was observed in contrast to the pale fluorescence of wild animals. It seems likely that serotonin replaces the deficient histamine in the heparin-biogenic amine complex in the mast cell granules.

Hormones in the nucleus. Immunologically demonstrable biogenic amines (serotonin, histamine) in the nucleus of rat peritoneal mast cells

Using 1-ethyl-3(3-dimethyl-aminopropyl)-carbodiimide (EDAC) fixation and immunocytochemical confocal microscopic study, bright serotonin and histamine fluorescence appeared in the nucleus of rat peritoneal mast cells. In case of paraformaldehyde fixation, this was not observed. The phenomenon can be explained by the cross-linking effect of EDAC, which did not allow the efflux of biogenic amines from the nucleus. This means that biogenic amines are present in the nucleus of mast cells, and this is supported by the flow cytometric measurement data of the whole cell. Other hormones studied (triiodothyronine, insulin, and endorphin) were not present in the nucleus. Four pharmaca with biogenic amine-influencing character in the central nervous system were used for studying the relation between the external (surrounding and cytoplasmic) and nuclear biogenic amine content of mast cells. Fluoxetine, a serotonin reuptake inhibitor depleted nuclear as well as cytoplasmic serotonin content. Clorgyline, a MAO-A inhibitor, decreased cytoplasmic serotonin content and weakened nuclear serotonin fluorescence. The tryptophan hydroxylase inhibitor, para-chlorophenylalanine (PCPA), and the mast cell degranulator, Compound 48/80, reduced cytoplasmic serotonin content without influencing nuclear content. Histamine fluorescence was influenced solely by fluoxetine. The results show that nuclear 5-HT content is dependent firstly of serotonin uptake and reuptake. To our knowledge, this is the first exact report on the presence of non-steroid-type-receptor-transported hormones inside the nucleus of a cell.

Characterization of the ultrastructure of gingival mast cells in alloxan‐induced diabetic rats

The morphological changes of gingival mast cells of alloxan-induced diabetic rats were studied by electron microscopy. The following observations were made. The cell nucleus and cytoplasm degenerated. The electron density of the granules in the cell cytoplasm clearly decreased. Some granules had dense irregular threads and the granules were surrounded by a thin vacuole. A ghost vacuole formed in some mast cells and disorganized materials accumulated in the cytoplasm. The mast cell nuclei were generally irregular and degenerating mast cells had pyknotic nuclei. General destruction of the cell membrane and granule shedding in some samples was noted and mitochondria with atypical cristae in the cytoplasm of the mast cells were seen. We conclude that the characteristics of the ultrastructure of gingival mast cells in diabetics are distinctive and should be used as criteria for pathogenesis of gingival inflammation.

Development of markers for human basophils and mast cells

Development of markers for human basophils and mast cells

Reactivation of rat peritoneal leukocyte and mast cell nuclei in heterokaryons with actively growing mouse cells

Leukocytes and mast cells of rat peritoneal exudate (PE) were fused in vitro with actively growing mouse cells. Segmented ring-shaped nuclei of granulocytes undergo drastic changes which result in dispersion of tightly condensed chromatin and gradual disappearance of the opening in the centre of the nucleus. These changes are paralleled by a resumption of RNA and DNA synthesis, as shown by autoradiography with [ 3H]uridine and [ 3H]thymidine. Solid inactive nuclei of mast cells, lymphocytes, monocytes and macrophages also resume DNA replication and high level of RNA synthesis. Fusion of thymidine kinase-deficient 3T3–4E cells with PE cells results in the incorporation of [ 3H]thymidine into the nuclei of heterokaryons. This may be considered evidence of the phenotypic expression of rat thymidine kinase gene in heterokaryons. A similar way in which segmented and non-segmented dormant nuclei undergo reactivation suggests that the reversibility of nuclear inactivation is a common feature of differentiated somatic cells.

DNA distribution of mast cell populations in growing rats.

The proliferation of rat peritoneal mast cells was examined under normal conditions in vivo. DNA content of individual mast cells was measured by cytofluorometry after staining with the bibenzimidazole dye Hoechst 33258. Diploid non mast cells from each rat were used as a biological standard, which resulted in small long-term variations in the method. The proportion of mast cells in the S + G2 region of the DNA distribution was about 4% for young rats (24 days old, body-weights about 60 g). It decreased in relation to body-weight, and was less than 1% for 105-day-old rats weighing 400 g. During the same growth period the total number of mast cells in the peritoneal cavity increased about 8-fold. The total number of proliferating cells, about 30,000, remained constant throughout the observation period. No evidence of polyploidization or accumulation in G2 of mast cell nuclei was found. It is concluded that peritoneal mast cells increase in number by mitotic proliferation of differentiated cells.

Unique deposits in mast cells fixed with pyroantimonate osmium tetroxide

Evidence for a unique cation distribution in mast cells in a variety of tissues was obtained by fixation with a modification of the potassium pyroantimonate-osmium tetroxide procedure of Komnick. Fine antimonate deposits with a heterochromatin distribution were abundant in nuclei of other cell types but were diminished to absent in mast cell nuclei. Nuclei of mast cells usually contained large coarse precipitates which measured 100–150 nm in diameter and were distributed peripherally, as well as less coarse deposits, which measured about 50 nm, and were distributed throughout the nucleus. Cytoplasmic deposits distributed in Golgi vesicles, between granules and at the plasmalemma were observed in some cells. It is suggested that these unusual deposits result from precipitation of antimonate by histamine or by cations whose distribution is affected by the highly ionic materials present in mast cells. Mast cells of man differed from those of rodents in containing cytoplasmic lipid droplets with peripheral antimonate deposits.

Early Mast Cell Responses in Mouse Popliteal Lymph Nodes to Localized Primary Antigenic Stimuli

Abstract Mast cell responses were quantitated in the regional draining lymph nodes of mice during the first 24 hr after primary footpad stimulation with three concentrations each of three soluble protein antigens. The time and intensity of response varied with the type and dosage of antigen. Immunization with 50 µg of bovine serum albumin (BSA) and ferritin induced the highest mast cell responses, with peak counts five times the normal mean at 5 and 3 hr, respectively. A low antigenic dose (10 µg) of BSA or ferritin stimulated peak responses at 16 hr, and the greatest response to 7.5 µg of sulfanilazo porcine γ globulin was observed at 3 hr. At doses of 100 to 150 µg, the three antigens yielded variable results and established no definite response patterns. During peak responses the mast cells accumulated in large clusters in the interfollicular cortex and medullary regions of the nodes. No degranulation or disruption of mast cells was observed, indicating the absence of “cytophilic antibodies” on the cell surfaces. Autoradiography was employed to study the incorporation of tritiated thymidine by responding mast cells at hourly intervals through the first 24 hr after immunization. No tritium was observed in mast cell nuclei, suggesting that the mast cell responses were not due to rapid cell proliferation.