Induction of histamine release from rat mast cells by bradykinin analogues

Independently of their agonistic or antagonistic activity on different isolated tissue preparations, the kinin analogues investigated induce histamine release on rat peritoneal mast cells. The effectivity of most compounds is 10 to 100 times higher than that of bradykinin. Beside the positively charged amino acids, the elongation at the N-terminus with hydrophobic amino acids and the replacement of amino acids in the bradykinin sequence (especially at position 7) with aromatic residues is important for a high histamine-releasing activity.     

实电解质钙可诱发人肥大细胞组胺和类胰蛋白酶分泌

目的: 利用人大肠组织的肥大细胞和肥大细胞激活的体外研究系统,评价实电解质钙(calcium ionophore A23187, CI)诱导肥大细胞释放类胰蛋白酶和组胺的能力和机制.方法: 经酶悬浮的人大肠肥大细胞与CI共同培养后收集上清液,并用酶联免疫吸附试验(ELISA)的方法检测类胰蛋白酶分泌量,用以玻璃纤维为基础的荧光比色法检测组胺释放量.结果: 经过15 min的培养,CI可引起浓度相关性的组胺和类胰蛋白酶释放.其中组胺的最大分泌量比基础分泌量超出了5.3倍以上,而类胰蛋白酶的最大分泌量则比基础分泌量超出了2.8倍以上.CI在浓度高于1.0 μmol/L时引起的组胺释放量明显多于类胰蛋白酶释放量.时间关系曲线显示,CI的作用从加样后10 s开始,6 min后达高峰并至少持续15 min.百日咳毒素和代谢抑制剂均能抑制CI引起的组胺和类胰蛋白酶释放.结论: 人大肠肥大细胞在受到CI刺激时具有释放类胰蛋白酶和组胺的能力,这个过程与肥大细胞膜G蛋白偶联受体的激活有关,并消耗能量.     

Strain differences in histamine release from mouse peritoneal mast cells induced by compound 48/80 or A23187

Strain differences among BALB/c, BDF1, CDF1, C3 H/He, C57 BL/6, DBA/2, ddy and ICR mice were investigated with respect to the ratios of histamine release from mouse peritoneal mast cells induced by compound 48/80, a Ca2+ dependent histamine releaser, and the Ca2+ ionophore A23187. The ratios of histamine release from mouse peritoneal mast cells induced by compound 48/80 were found to be high in BALB/c, ddY and ICR mice, but low in BDF1, CDF1, C3 H/He, C57 BL/6 and DBA/2 mice. Those induced by Ca2+ ionophore A23187 were high in BALB/c, BDF1, CDF1, C3 H/He, DBA2, ddy and ICR mice but low in C57 BL/6 mice. These results indicate that differences in histamine release from mouse peritoneal mast cells are strain dependent.     

Effect of calcium on histamine release from pleural and peritoneal mast cells induced by catechol

Histamine release from rat pleural and peritoneal mast cells induced by catechol (1, 10, 50, 250 microM and 1 mM) has been studied. The dose-response induced by catechol is non-cytotoxic, is not modified by purification of mast cells and is calcium independent. The sensitivity and maximum response to catechol is the same irrespective of the presence or absence of Ca++, except on purified pleural mast cells, that showed a plateau response at 250 microM catechol in the absence of Ca++, and on unpurified peritoneal mast cells which exhibited a lower maximum response equally in the absence of Ca++. The release is induced by catechol at concentrations as low as 50 microM in all cases, and the maximum response is reached at 1 mM.     

Trichinella spiralis: histamine secretion induced by TSL-1 antigens from unsensitized mast cells

Mast cells' hyperplasia and activation are prominent features in Trichinella spiralis infection. Recently, it was shown that TSL-1 antigens from T. spiralis muscle larvae induce IL-4 and TNF release by unsensitized, normal mast cells (MC) involving an Ig-independent mechanism. In this study, we characterized histamine secretion induced by TSL-1 antigens from normal, unsensitized rat peritoneal MC. Maximum histamine secretion (30+/-5.3% SEM, n=13) was achieved with 30 ng/mL TSL-1 antigens. However, TSL-1 did not induce an increase in beta-hexosaminidase release or NADPH oxidase activity by MC. Interestingly, histamine secretion by TSL-1 was completed at 10s, and was inhibited by both Bordetella pertussis toxin and neuraminidase V, characteristics similar to those involved in substance P-induced histamine secretion. However, in contrast to substance P, TSL-1 induced histamine secretion in the absence of detectable changes in intracellular Ca(2+). We are investigating the molecular pathways involved in MC activation by TSL-1.     

Biochemical analysis of glucocorticoid-induced inhibition of IgE-mediated histamine release from mouse mast cells

Pretreatment of mouse mast cells with 10(-7) to 10(-6) M dexamethasone (DM) during overnight sensitization with mouse IgE antibody resulted in inhibition of antigen-induced histamine release and degranulation. The inhibition of both degranulation and histamine release increased linearly with the duration of the treatment; maximal inhibition was obtained after approximately 16 hr with DM. The addition of DM to sensitized mast cells immediately before antigen challenge did not affect the antigen-induced histamine release. DM interacted directly with mast cells by binding to DM-specific cytoplasmic receptors. The treatment of mast cells with DM did not affect the binding of IgE to mast cells or intracellular cAMP levels. Bridging of cell-bound IgE anti-DNP antibody on mouse mast cells either by multivalent DNP-HSA or by anti-IgE induced phospholipid methylation at the plasma membrane and Ca++ influx into the cells. Pretreatment of mast cells with DM inhibited the antigen-induced phospholipid methylation and Ca++ uptake but failed to affect histamine release by Ca++ ionophore A23187. The results suggest that DM treatment inhibits histamine release by the inhibition of the early stage of biochemical processes leading to opening Ca++ channels but does not affect the process distal to Ca++ influx or the binding of IgE molecules to IgE receptors.     

Platelet factor 4 fragment induces histamine release from rat peritoneal mast cells

Platelet factor 4 (PF-4) belongs to a superfamily of low-molecular weight proteins known as chemokines. However, its function has not been fully evaluated. In the present study, we investigated the effect of PF-4 on histamine release from rat peritoneal mast cells by employing its biologically-active carboxyl-terminal fragment, PF-4 (58-70). PF-4 (58-70) stimulated histamine release from mast cells in a dose-dependent manner (10(-8) to 10(-5)M). Histamine release induced by PF-4 (58-70) occurred rapidly (<30s) and was inhibited by extracellular Ca(2+). These results suggest that PF-4 might play a crucial role at the site of inflammation and/or immune response.     

Inhibition of compound 48--80 induced histamine liberation from mast cells by triton X-100]

Triton X-100 at concentrations preceding those which liberated histamine, produced dose-dependent inhibition of compound 48/80-induced histamine release from rat mast cells. Triton X-100 (0.00002 1/1) depleted ATP content in the mast cells and blocked compound 48/80-induced histamine release. The inhibition of compound 48/80-induced histamine release and depletion of the ATP content in the mast cells was reversed by glucose (10 mmole). It is concluded that inhibition by Triton X-100 of histamine release induced by compound 48/80 is dependent on inhibition of energy production.     

IgE-mediated release of histamine from human cutaneous mast cells

We investigated the ability of antigen-IgE interactions to stimulate histamine release from human infant cutaneous mast cells. Skin obtained at circumcision contained numerous perivascular mast cells, as assessed by light and electron microscopy. The histamine content of this tissue averaged 17.7 ng (+/- 1.5 SEM)/mg wet weight. Challenge of 200-microns thick sections of unsensitized skin with varying concentrations of monoclonal murine antibodies to human IgE caused no net release of histamine. After skin sections were incubated in the presence of 5 micrograms/ml of human myeloma IgE (S) for 120 min at 37 degrees C, monoclonal anti-IgE challenge resulted in 40.1% (+/- 6.0 SEM) histamine release. Similar passive sensitization with 1/20 dilutions of serum from humans expressing IgE to purified Juniperus sabinoides (JS) antigen rendered the tissue responsive to specific antigen challenge. Dose-related histamine release occurred over 30 min with optimal release of 12.6% (+/- 2.4 SEM) after stimulation with 100 ng/ml of JS antigen. This reaction required sensitization with serum containing IgE to JS and was antigen-specific. Optimal reactions to antigen occurred at 3 mM added Ca++, 34 degrees C to 37 degrees C, pH 7.2. Antigen-induced release was markedly influenced by the added Ca++ concentration; no release occurred in the absence of Ca++, 54% of the optimal response was observed at 2 mM Ca++, and 28% of the optimal response occurred at 4 mM Ca++. The addition of Mg++ did not influence antigen-induced release. The results of this study provide functional evidence that 1) human infant cutaneous mast cells express Fc-epsilon receptors; 2) these receptors are largely unoccupied in vivo; and 3) stimulation of passively sensitized infant mast cells with anti-IgE or specific antigen leads to immediate histamine release. This new system should permit detailed in vitro studies of immediate hypersensitivity reactions in human skin.     

Magainin-2 releases histamine from rat mast cells.

The magainins are basic 23 amino acid peptides with a broad spectrum of antimicrobial activity. Their bactericidal effect has been attributed to their capacity to interact with lipid bilayer membranes. We observed histamine release by magainin-2 amide from rat peritoneal mast cells (ED50 = 13 micrograms/ml) but not from human basophils. This histamine-releasing reaction from peritoneal mast cells was due to a secretory rather than cytolytic effect, i.e., release occurred without concomitant liberation of lactic dehydrogenase. Furthermore, the pretreatment of mast cells with magainin-2 amide did not desensitize cells against subsequent challenge with other secretagogues. Maximum histamine release occurred in less than a minute at 25 and 37 degrees C. The addition of Ca2+ was not required for histamine release, although release was enhanced by the addition of 0.3-1 mM Ca2+. The addition of 3 mM Ca2+ or Mg2+ was markedly inhibitory. The presence of Na+ or Cl- ions in the medium was not required for release. Therefore, histamine release is not due to the formation of anion-selective channels in the membrane of mast cells. The results indicated that the characteristics of histamine secretion induced by magainin-2 amide were unlike IgE-mediated release but were similar to the mechanism of release attributed to some other basic peptides and to compound 48/80.     

Calcium requirement for the inhibition by theophylline of histamine release from mast cells

When added to Ca2+-free Hanks' solution, Ca2+ (0.1-2.5 mM) had no significant effect on antigen-induced histamine release from rat mast cells, but Sr2+ (1.0-3.0 mM) dose-dependently increased the release. Ba2+ (1.0 and 2.0 mM) also enhanced the release. Ca2+ and Ba2+ inhibited compound 40/80-induced histamine release, in a dose-dependent manner. In ordinary Hanks' medium, theophylline and 3-isobutyl-1-methylxanthine (IBMX) dose-dependently inhibited the antigen-induced histamine release but these drugs were ineffective in Ca2+-free medium. Theophylline (1.0 mM) also inhibited compound 48/80-induced histamine release in the presence but not absence of Ca2+. There was an optimal Ca2+ concentration for the theophylline effect. Sr2+ but not Ba2+ could substitute for Ca2+ in supporting the theophylline effect. Theophylline (1.0 mM) and IBMX (1.0 mM) increased mast cell cyclic AMP levels both in the presence and absence of Ca2+. These results suggest that Ca2+ is required in the interaction of theophylline and specific sites on mast cells or in the mast cell response to theophylline which probably does not involve the cyclic AMP increase and is linked to the inhibition of histamine release.     

Mechanisms in bradykinin stimulated arachidonate release and synthesis of prostaglandin and platelet activating factor

Regulatory mechanisms in bradykinin (BK) activated release of arachidonate (ARA) and synthesis of prostaglandin (PG) and platelet activating factor (PAF) were studied in bovine pulmonary artery endothelial cells (BPAEC). A role for GTP binding protein (G-protein) in the binding of BK to the cells was determined. Guanosine 5-O- (thiotriphosphate), (GTPtauS), lowered the binding affinity for BK and increased the Kd for the binding from 0.45 to 1.99 nM. The Bmax remained unaltered at 2.25 x 10(-11) mole. Exposure of the cells to aluminium fluoride also reduced the affinity for BK. Bradykinin-induced release of ARA proved pertussis toxin (PTX) sensitive, with a maximum sensitivity at 10 ug/ml PTX. GTPtauS at 100 muM increased the release of arachidonate. The effect of GTPtauS and BK was additive at suboptimal doses of BK up to 0.5 nM but never exceeded the levels of maximal BK stimulation at 50 nM. PTX also inhibited the release of ARA induced by the calcium ionophore, A23187. Phorbol 12-myristate 13-acetate or more commonly known as tetradecanoyl phorbol acetate (TPA) itself had little effect on release by the intact cells. However, at 100 nM it augmented the BK activated release. This was downregulated by overnight exposure to TPA and correlated with down-regulation of protein kinase C (PKC) activity. The down-regulation only affected the augmentation of ARA release by TPA but not the original BK activated release. TPA displayed a similar, but more potent amplification of PAF synthesis in response to both BK or the calcium ionophore A23187. These results taken together point to the participation of G-protein in the binding of BK to BPAEC and its activation of ARA release. Possibly two types of G-protein are involved, one associated with the receptor, the other activated by Ca(2+) and perhaps associated with phospholipase A(2) (PLA(2)). Our results further suggest that a separate route of activation, probably also PLA(2) related, takes place through a PKC catalysed phosphorylation.