Different responses of rodent mast cells to lysophosphatidylserine

The lysophosphatidylserine-induced activation of mast cells has been studied in preparations obtained from different rodents. In mouse and gerbil peritoneal mast cells lysophosphatidylserine behaves as an agonist, inducing noncytotoxic histamine release at 0.2–8 M. In rat peritoneal and pleural mast cells lysophosphatidylserine is ineffective, but the histamine-releasing activity becomes manifest upon the addition of suboptimal concentrations of other mast cell activators. The common structure-activity relationship shows the link between these effects of lysophosphatidylserine but the calcium requirement indicates differences in the mechanism of action. Histamine release in mouse mast cells is independent of external calcium. Thus, lysophosphatidylserine induces mobilization of endogenous calcium stores in these cells. By contrast, histamine release in gerbil and rat mast cells is dependent on the addition of external calcium indicating that the phospholipid promotes calcium influx. While in gerbil mast cells calcium influx is promoted by lysophosphatidylserine alone, in rat it requires the combined action of the phospholipid and other mast cell agonists. Differently from lysophosphatidylserine, compound 48/80 elicits histamine release in rat and gerbil mast cells. Mouse mast cells are unaffected. Thus, gerbil mast cells are the only preparation in which the action of these two agonists can be observed simultaneously.     

Anti-allergic effect of lambertianic acid from Thuja orientalis in mouse bone marrow-derived mast cells

Lambertianic acid is a bioactive diterpene found in the leaves of Thuja orientalis. Its effect on the bone marrow-derived mast cell (BMMC) mediated allergy and inflammation mechanism remains unknown. In this study, lambertianic acid was evaluated for its effect on the allergic mediators, including prostaglandin D(2) (PGD(2)), leukotriene C(4) (LTC(4)), β-hexosaminidase (β-Hex) and cyclooxygenase-2 (COX-2) protein, in phorbol 12-myristate 13-acetate (PMA) plus calcimycin-stimulated BMMCs. The results revealed that lambertianic acid inhibited the production of interleukin-6 (IL-6), PGD(2) and LTC(4), the expression of COX-2 and the degranulation of β-hexosaminidase in the PMA plus calcimycin-induced BMMCs. Taken together, these findings implied that lambertianic acid may possess the potential in the treatment of allergy.     

Prostaglandin D2 generation in mouse bone marrow-derived mast cells exposed to dexamethasone is associated with endogenous peroxidase activity

The appearance of fixative-sensitive peroxidase activity in the nuclear envelope and endoplasmic reticulum of bone marrow-derived mast cells (BMMC) cultured in the presence of 1 microM dexamethasone (DM) for up to 14 days and its relationship with immunologic release of prostaglandin D2 (PGD2) by these cells were studied. Endogenous peroxidase activity, previously shown as a marker of arachidonic acid metabolism in various cell types, was visualized by cell incubation in 3,3' diaminobenzidine-containing solution before glutaraldehyde fixation. PGD2 release was induced by passive sensitization of BMMC with an optimal dose of monoclonal IgE and subsequent challenge with specific a antigen. We found that 4-week-old BMMC, used as the starting population of the present study, exhibited immature morphologic features, did not present peroxidase activity when cytochemically processed, and released minute amounts of PGD2 in response to IgE-dependent stimulation. When such BMMC were exposed to DM during 24 hours, they showed aldehyde-inhibited peroxidase activity in the perinuclear envelope and a few endoplasmic reticulum segments. As compared with untreated cells, 24-hour DM-exposed BMMC released higher amounts of PGD2 upon immunologic stimulation. After an additional 14-day period of DM exposure, an intense peroxidase activity was detected in the perinuclear envelope and the endoplasmic reticulum of BMMC, which, under immunologic stimulation, released as much as 42.4 +/- 14.7 ng of PGD2/1 x 10(6) cells. Aminotriazole (20 and 50 mM) extinguished both peroxidase activity and PGD2 release from BMMC whereas indomethacin (1 microM) suppressed PGD2 production, but did not alter endogenous peroxidase activity. Previous cell fixation with glutaraldehyde totally inhibited endogenous peroxidase reaction in DM-exposed BMMC. Moreover, 14-day DM-exposed BMMC exhibited morphologic characteristics of mature mast cells and possessed alcian blue+/safranin+ granules. Therefore, the present data suggest that appearance of peroxidase activity in the nuclear envelope and the endoplasmic reticulum of DM-exposed BMMC is associated with the ability of the cells to synthetize PGD2 and appears as a cytochemical marker of the in vitro maturation of mouse bone marrow-derived mast cells.     

Effect of intracellular histamine on the gene expression profile in mouse bone marrow-derived mast cells

Inflammation Research -     

Specific antigen targeting to surface IgE and IgG on mouse bone marrow-derived mast cells enhances efficiency of antigen presentation.

The discovery that bone marrow-derived mast cells can express major histocompatibility complex class II molecules and act as antigen-presenting cells prompted us to evaluate this function when antigen is internalized through fluid-phase endocytosis or via specific uptake by using IgG and IgE antibodies. This study was performed using a specific T-cell hybridoma developed against Lol p 1, the major allergen of grass pollen Lolium perenne. Expression of Fc gamma R and Fc epsilon RI by mast cells led us to investigate the influence of IgG- and IgE-targeted antigen on the antigen-presenting function of mast cells. Internalization of Lol p 1 through different specific IgG monoclonal antibodies (mAb) resulted in the activation of Lol p 1-specific T-cell hybridoma at concentrations about 100-fold less than that required for T-cell stimulation by uncomplexed antigen. IgE-complexed Lol p 1, which facilitates trapping of antigen by mast cells, induced an accelerated and more efficient antigen-presenting capacity of mast cells than that obtained with uncomplexed antigen. However, aggregation of anti-dinitrophenyl (DNP) IgE mAb by the irrelevant antigen DNP-human serum albumin did not substantially increase the capacity of mast cells to present Lol p 1 to T cells. This suggests that the mere aggregation of Fc epsilon RI is not sufficient for enhanced antigen presentation mediated by IgE. Tissue distribution and strategic location of mast cells at the mucosal barriers and their capacity to process the antigen through efficient fluid-phase pinocytosis as well as IgG- and IgE-dependent targeting of antigens provide mast cells with a prominent role in immune surveillance.     

Gomisin N has anti-allergic effect and inhibits inflammatory cytokine expression in mouse bone marrow-derived mast cells

Gomisin N is a bioactive compound and a prominent anti-allergic agent found in the fruits of tree Schizandra chinensis. However, its effects on the bone marrow-derived mast cell (BMMC)-mediated allergy and inflammation mechanism remain unknown. In this study, the biological effects of gomisin were evaluated while focusing on its effects on the allergic mediator in PMA + A23187-stimulated BMMCs. The anti-allergic effect of gomisin has shown that inhibited PMA + A23187-induced interleukin-6 (IL-6) production. An investigation was also conducted to determine its effects on the production of several allergic mediators including prostaglandin D(2) (PGD(2)), leukotriene C(4) (LTC(4)), β-hexosaminidase (β-Hex), and cyclooxygenase-2 (COX-2) protein. The results revealed that gomisin inhibited the PMA + A23187-induced production of IL-6, PGD(2), LTC(4), β-Hex, and COX-2 protein. Taken together, these findings indicate that gomisin N has the potential for use in the treatment of allergy.     

Gomisin N has anti-allergic effect and inhibits inflammatory cytokine expression in mouse bone marrow-derived mast cells

Gomisin N is a bioactive compound and a prominent anti-allergic agent found in the fruits of tree Schizandra chinensis. However, its effects on the bone marrow-derived mast cell (BMMC)-mediated allergy and inflammation mechanism remain unknown. In this study, the biological effects of gomisin were evaluated while focusing on its effects on the allergic mediator in PMA + A23187-stimulated BMMCs. The anti-allergic effect of gomisin has shown that inhibited PMA + A23187-induced interleukin-6 (IL-6) production. An investigation was also conducted to determine its effects on the production of several allergic mediators including prostaglandin D₂ (PGD₂), leukotriene C₄ (LTC₄), β-hexosaminidase (β-Hex), and cyclooxygenase-2 (COX-2) protein. The results revealed that gomisin inhibited the PMA + A23187-induced production of IL-6, PGD₂, LTC₄, β-Hex, and COX-2 protein. Taken together, these findings indicate that gomisin N has the potential for use in the treatment of allergy.     

Cultured human bone marrow-derived mast cells, their similarities to cultured murine E-mast cells

Homogeneous populations of human mast cells were differentiated and grown by culturing bone marrow cells in the presence of conditioned medium derived from lectin-stimulated human peripheral blood mononuclear cells. The cells obtained were similar in ultrastructure, proteoglycan type and lipid products generated upon calcium ionophore A23187, and immunological activation to the murine E-mast cells (E-MC) differentiated in culture containing IL-3. Fluorescence analysis revealed that the human E-MC expressed IgE-Fc receptors which retained bound IgE through several washes. These cells did not express cell-surface lymphoid determinants (T11, T4, T8 and B4) and myeloid determinants 'My'. However, 40% of these cells expressed monocytic surface determinants, such as M-1. The amount of histamine that was found per 10(6) cells was 525 +/- 106 ng (mean +/- SE, n = 4). These cultured mast cells possessed granular chondroitin sulphate E proteoglycan of about 180,000 MW. Following activation with either calcium ionophore A23187 or anti-hIgE challenge, these mast cells released their preformed mediators and generated mainly leukotriene C4 leukotriene B4, and platelet-activating factor. In conclusion, according to all of these criteria, these human cultured mast cells show many similarities to the murine cultured E-mast cells, and therefore could be considered as the culture analogue of the human intestinal E-mast cells identified recently.     

Microenvironmental regulation of inducible nitric oxide synthase expression and nitric oxide production in mouse bone marrow-derived mast cells

In addition to its well-known role in relaxation of vascular smooth muscle, NO modulates immune responses in a concentration- and location-specific manner. For MC, it is well accepted that exogenous NO regulates their function. However, there are inconsistencies in the literature of whether MC express NOS and make NO. MC progenitors mature in peripheral tissues, but the factors that influence MC maturation and their specific phenotype, such as whether they express NOS, are not well understood. To study microenvironmental conditions that could be "permissive" for NOS expression, we cultured BMMC in various conditions--BMMC(IL-3), BMMC(SCF/IL-3), or BMMC(SCF/IL-4)-for >3 weeks and examined NOS expression. We detected Nos2 mRNA in BMMC(SCF/IL-4) but not BMMC(IL-3) or BMMC(SCF/IL-3). After stimulation with IFN-γ and/or LPS, NOS2 expression and NO production were detected in BMMC(SCF/IL-4) but rarely detected in BMMC cultured with other conditions. Confocal microscopic analysis showed that NOS2 expression induced by IFN-γ colocalized in CD117(+) BMMC. NO production, after activation with IFN-γ and LPS in BMMC(SCF/IL-4), was abrogated by pretreatment with the NOS2-specific inhibitor. In addition to NOS2 expression, BMMC(SCF/IL-4) were distinguished from BMMC(IL-3) in heparin and MMCP expression. Thus, MC progenitors that develop in SCF + IL-4 can be induced to express NOS2 after receiving appropriate signals, such as IFN-γ, and subsequently produce NO. Microenvironmental conditions during their development can influence whether MC are capable of NOS expression and of NO production.     

Heterogeneity of murine bone marrow-derived mast cells: analysis of their proteinase content.

The expression of granule proteinases by murine bone marrow-derived mast cells (BMMC) grown in vitro was compared with that of serosal mast cells (SMC) from the peritoneal cavity. The granules in a proportion of BMMC (0.4-13%) and in all SMC were labelled with fluorescent antibodies against rat mast cell protease I (RMCP I). The granules of 1-47% of BMMC and 100% of SMC were labelled with antibodies against a 30,000 molecular weight (MW) murine intestinal mast cell proteinase (MIMCP). Four antigens from BMMC, ranging in MW from 28,000 to 32,000 and a single 28,000 antigen from SMC were detected on Western blot using anti-MIMCP antibodies. Only the 28,000 MW antigens from BMMC and SMC were visualized in blots probed with anti-RMCP I. BMMC grown in the presence of conditioned medium from activated splenocytes or from the WEHI-3B myelomonocytic cell line contained 52-118 ng and 3-25 ng MIMCP/10(6) cells respectively, whereas SMC lacked detectable MIMCP. The selective labelling of the 28,000 MW antigens in BMMC and SMC with anti-RMCP I and the variable expression of this antigen in BMMC as detected by immunofluorescence indicates that BMMC are not a homogeneous population of cells.     

Thrombin-induced degranulation of cultured bone marrow-derived mast cells: effect on calcium uptake.

The role of calcium in the mechanism of thrombin activation of bone marrow-derived mast cells (BMMC) was explored by measuring the changes in the uptake of 45Ca2+ into quiescent BMMC and into cells stimulated by thrombin or by IgE-antigen. The results indicate that activation of BMMC by either thrombin or IgE-antigen is Ca2+-dependent. One million BMMC, activated by 0.05-5 U thrombin, accumulated 45Ca2+ in a concentration-dependent manner, which levelled off at around 1 U thrombin. Extracellular 45Ca2+ uptake of thrombin-stimulated cells is saturable within 90 seconds and corresponds to the kinetics of histamine release, whereas that of IgE-antigen exposed cells continues unabated for over 5 min. The pattern of 45Ca2+ uptake of IgE-sensitized BMMC exposed to thrombin suggests that the pro-stimulatory locus of thrombin action on the surface membrane is distinct from that of IgE.     

Rat mucosal mast cells: the cultured bone marrow-derived mast cell is biochemically and functionally analogous to its counterpart in vivo.

Mast cells (MC) are biochemically and functionally heterogeneous and the mixture of MC phenotypes varies according to anatomical location. Intestinal mucosal MC (IMMC) have been used to study the mucosal MC subset in the rat, but they are difficult to isolate in sufficient numbers and with consistent purity and viability. Bone marrow-derived MC (BMMC), with an apparent mucosal MC phenotype, can be cultured in large numbers and with high purity from normal rat bone marrow using supernatants from mesenteric lymph node cells of rats infected with the nematode, Nippostrongylus brasiliensis. We have compared serine proteinase content, tumour necrosis factor-alpha (TNF-alpha) storage and secretion, and TNF-alpha-dependent cytotoxicity of IMMC and BMMC to assess the appropriateness of BMMC as in vitro models of mucosal MC. Two-dimensional gel electrophoretic analysis revealed that the overall protein constituents of BMMC and IMMC were highly homologous. Immunoblotting confirmed that both MC types expressed the MMC-associated enzyme, rat mast cell proteinase-2 (RMCP-2), but not RMCP-1, mast cell proteinase-5 (MCP-5) or carboxypeptidase A (CPA), which characterize the connective tissue MC in the rat and which were detected in a representative of this subset, namely, the periotoneal MC (PMC). BMMC demonstrated levels of TNF-alpha-dependent cytotoxicity that were equivalent to those of IMMC. Like IMMC, BMMC contained little stored TNF-alpha, in comparison with PMC, but both MC types generated substantial amounts of TNF-alpha 6 hr following IgE-mediated activation. Pretreatment of PMC with recombinant rat interferon-gamma (IFN-gamma) for 20 hr inhibited anti-immunoglobulin E (anti-IgE)-mediated release of the granule-associated enzyme, beta-hexosaminidase, whereas identically treated BMMC were unresponsive to this cytokine. Similar results have previously been reported for IMMC. Rat BMMC, unlike their more immature and less phenotypically committed counterparts in the mouse, appear therefore to be more appropriate models for studies on the mucosal MC.     

Cloned mouse mast cells derived from immunized lymph node cells and from foetal liver cells exhibit characteristics of bone marrow-derived mast cells containing chondroitin sulphate E proteoglycan

Cloned mouse mast cells which were T cell growth-dependent were derived both from immunized lymph node and from foetal liver, and were found to be morphologically and biochemically similar to mast cells previously differentiated in vitro from mouse bone marrow (BMMC). These two T cell growth-dependent mouse mast cell clones were identical to the BMMC in their preferential synthesis of chondroitin sulphate E proteoglycan rather than heparin proteoglycan. The hydrodynamic size of the cell-associated proteoglycan from each of the three mast cell sources was 150,000-250,000 mol. wt.; and that of the covalently bound glycosaminoglycans was 13,000-25,000 mol. wt. Chondroitinase ABC digestion of the [35S]proteoglycans from both cloned mast cells, as well as the BMMC, yielded only two disaccharides which comigrated on ascending thin layer chromatography with delta Di-4S and delta Di-diSE standards, respectively. Quantification of the radioactivity in the enzyme digests revealed that one-sixth to one-half of the resulting disaccharides were disulphated, similar to that found in BMMC containing chondroitin sulphate E. When sensitized with monoclonal IgE, washed, and subsequently challenged with specific antigen, each of the two cloned mast cells generated more than 100 ng of leukotriene C4 (LTC4)/10(6) cells, but only 3-12 ng leukotriene B4 (LTB4)/10(6) cells, characteristics also observed for the BMMC. Based upon these observations, it is concluded that the cloned mast cells from lymph node and liver and the bone marrow-derived mast cell belong to a distinct subclass of mast cells. These mast cells have been designated E-mast cells (E-MC) in order to distinguish them from heparin-containing mast cells (H-MC).     

Anti-allergic effects of sinomenine by inhibition of prostaglandin D2 and leukotriene C4 in mouse bone marrow-derived mast cells

Sinomenine is an alkaloid compound and a prominent anti-allergic agent found in the root of the climbing plant Sinomenium acutum. However, its effects on the bone marrow-derived mast cell (BMMC) mediated allergy and inflammation mechanism remain unknown. In this study, the biological effects of sinomenine were evaluated while focusing on its effects on the allergic mediator in PMA plus A23187-stimulated BMMCs. An investigation was also conducted to determine its effects on the production of several allergic mediators including interleukin-6 (IL-6), prostaglandin D₂ (PGD₂), leukotriene C₄ (LTC₄), β-Hexosaminidase (β-Hex), and cyclooxygenase-2 (COX-2) protein. The results revealed that sinomenine inhibited the PMA plus A23187-induced production of IL-6, PGD₂, LTC₄, β-Hex, and COX-2 protein. Taken together, these findings indicate that sinomenine has the potential for use in the treatment of allergy.     

The culture of mouse bone marrow-derived mast cells (BMMC) and the anaphylactic release of chemical mediators]

Bone marrow cells from BALB/c, C3H/He and WBB6F1+/+ mice were cultured for 5 wks in the presence of the culture supernatant from prokoweed mitogen-stimulated spleen cells to assess and compare the degree of growth, proliferation and chemical mediator release of the mast cells (BMMC) derived from them. BMMC, which were positive to alcian blue staining, were found in the suspension cells on the culture of the bone marrow cells of either species of mice after 2 wk culture. The percentages of BMMC in the suspension cells were increased with time of culture, reaching more than 90% after 5 wks. No differences in the growth and proliferation rate among BMMC from these three species were observed. However, in regard to the amount of anaphylactic leukotriene (LT) and histamine release. BMMC from BALB/c mice were superior to those from other species. From the above results, subsequent experiments were executed with BMMC from BALB/c mice. There was no obvious difference in the releasability of anaphylactic mediators among BMMC obtained at any stages of the passage during 4-12 wk culture. On the other hand, although BMMC cultured for 4 and 5 wks well responded to Ca ionophore A23187 for these mediator release, those for 6 to 12 wks obviously deteriorated with prolongation of the culture. The time course of the anaphylactic release of immunoreactive (i-) LTB4, i-LTC4 and histamine from BMMC revealed that almost maximum release was reached at 10, 20 and 5 min, respectively, after antigen challenge. Several drugs including antiallergics and beta-stimulants had no effect on their release. From these results, it is suggested that present BMMC may be inadequate cells for evaluation of antiallergic drugs that can inhibit the anaphylactic mediator release, but may be useful for the research of the mechanism of the release because the cells likely release the mediators without occurrence of complicated subordinate reactions.     

P-selectin glycoprotein ligand-1 mediates rolling of mouse bone marrow-derived mast cells on P-selectin but not efficiently on E-selectin

It has been shown recently that mast cells play an essential role as a source of tumor necrosis factor-α production during neutrophil recruitment to sites of bacterial infection. Increased numbers of mast cells are indeed noted at sites of wound healing and inflammation. These cells are either recruited from the bone marrow or proliferate locally under cytokine stimulation. Little is known about how mast cell progenitors extravasate into tissue. Using antibody-like fusion proteins of mouse E-selectin and P-selectin, we have analyzed the ability of immature mouse bone marrow-derived mast cells (BMMC) to interact with the endothelial selectins. The P-selectin glycoprotein ligand-1 (PSGL-1) was affinity-isolated from detergent extracts of surface biotinylated BMMC with both selectin-IgG fusion proteins. However, only P-selectin-IgG, but not E-selectin-IgG showed significant interaction with intact BMMC as tested by flow cytometry and cell attachment assays with the immobilized fusion proteins under flow and non-flow conditions at physiological shear stress. Thus, in spite of carrying the necessary carbohydrate modifications which enable solubilized PSGL-1 to bind avidly to E-selectin, PSGL-1 on the surface of BMMC is presented in a way that prevents it from interacting efficiently with E-selectin. Affinity-purified rabbit antibodies against mouse PSGL-1 almost completely blocked the interaction of BMMC with P-selectin-IgG in flow cytometry as well as in cell adhesion assays under static and under flow conditions. Our data reveal that PSGL-1 is the major binding site for P-selectin on mouse BMMC progenitors, but does not support efficient interactions with E-selectin.     

小鼠骨髓来源内皮祖细胞体外诱导培养及分化特征

目的: 研究小鼠骨髓来源内皮祖细胞(EPCs)的体外培养方法及体外分化特征。方法: 采用梯度离心法分离小鼠骨髓单个核细胞并进行诱导培养,用流式细胞术和免疫细胞化学对细胞表型特征进行检测,分别采用MTT和Transwell方法对其增殖、迁移能力进行检测。结果: 体外培养4 d至14 d,CD133、SCA-1及CD117的表达率分别从11.05%、29.32%及16.45 %降至2.29%、7.82%及3.92%;而VEGFR-2、CD31、VE-cadherin、eNOS及vWF的表达率分别从12.21%、8.43%、18.27%、7.11%及32.61%增加至62.13%、32.96%、67.73%、27.89%及82.16%;吞噬acLDL和结合UEA-I的细胞从57.18%增加至86.70%。在0 μg/L至80 μg/L VEGF浓度梯度下,细胞增殖率和迁移率分别增加58.03%和33.83%。结论: EGM-2内皮培养基可稳定培养小鼠骨髓来源EPCs,培养过程中其干细胞标志物表达逐渐降低,而内皮细胞标志物表达及特性不断增加,VEGF可显著促进其增殖和迁移。