Rat Peritoneal Mast Cells (rat + peritoneal_mast_cell)

Distribution by Scientific Domains


Selected Abstracts


Antiallergic Activities of Pigmented Rice Bran Extracts in Cell Assays

JOURNAL OF FOOD SCIENCE, Issue 9 2007
Sun Phil Choi
ABSTRACT:, Using a panel of chemical, biochemical, and cell assays, we determined inhibitory effects of extracts of the pigmented black rice brans on in vitro allergic reactions. Ethanol-water (70% v/v) extracts from 5 pigmented brans were found to be more effective than an extract from a nonpigmented rice cultivar in suppressing the release of histamine and ,-hexosaminidase from basophilic RBL-2H3 cells stimulated with both Ionophore A23187 and immunoglobulin E (IgE)-antigen complexes. Suppression was also obtained with A23187-stimulated rat peritoneal mast cells. The extent of inhibition of these 2 markers of the immune response was accompanied by an influx of calcium ions. The inhibition of the immune process by the pigmented brans was confirmed by the observed modulation of the proinflammatory cytokine gene expressions and cytokine release, as indicated by the reduction in tumor necrosis factor (TNF)-,, interleukin (IL)-1,, IL-4, and IL-6 mRNA expressions determined with the reverse transcription-polymerase chain reaction (RT-PCR). Reduction of TNF-,, IL-1,, and IL-6 protein release from both the cultured cell line and peritoneal cells was further confirmed by enzyme-linked immunoadsorbent assays. Rice bran from the LK1-3-6-12-1-1 cultivar was the most effective inhibitor in all assays. This particular rice variety merits further evaluation as part of a human diet to ascertain its potential to protect against allergic diseases such as hay fever and asthma. [source]


Studies on the cellular uptake of substance P and lysine-rich, KLA-derived model peptides,

JOURNAL OF MOLECULAR RECOGNITION, Issue 1 2005
Johannes Oehlke
Abstract In the last decade many peptides have been shown to be internalized into various cell types by different, poorly characterized mechanisms. This review focuses on uptake studies with substance P (SP) aimed at unravelling the mechanism of peptide-induced mast cell degranulation, and on the characterization of the cellular uptake of designed KLA-derived model peptides. Studies on structure,activity relationships and receptor autoradiography failed to detect specific peptide receptors for the undecapeptide SP on mast cells. In view of these findings, a direct interaction of cationic peptides with heterotrimeric G proteins without the participation of a receptor has been proposed. Such a process would require insertion into and translocation of peptides across the plasma membrane. In order to clarify whether a transport of cationic peptides into rat peritoneal mast cells is possible, transport studies were performed by confocal laser scanning microscopy (CLSM) using fluorescence-labeled Arg3,Orn7 -SP and its D -amino acid analog, all- D -Arg3,Orn7 -SP, as well as by electron microscopic autoradiography using 3H-labelled SP and 125I-labelled all- D -SP. The results obtained by CLSM directly showed translocation of SP peptides into pertussis toxin-treated cells. Kinetic experiments indicated that the translocation process was rapid, occurring within a few seconds. Mast cell degranulation induced by analog of magainin 2 amide, neuropeptide Y and the model peptide acetyl-KLALKLALKALKAALKLA-amide was also found to be very fast, pointing to an extensive translocation of the peptides. In order to learn more about structural requirements for the cellular uptake of peptides, the translocation behavior of a set of systematically modified KLA-based model peptides has been studied in detail. By two different protocols for determining the amount of internalized peptide, evidence was found that the structure of the peptides only marginally affects their uptake, whereas the efflux of cationic, amphipathic peptides is strikingly diminished, thus allowing their enrichment within the cells. Although the mechanism of cellular uptake, consisting of energy-dependent and -independent contributions, is not well understood, KLA-derived peptides have been shown to deliver various cargos (PNAs, peptides) into cells. The results obtained with SP- and KLA-derived peptides are discussed in the context of the current literature. Copyright © 2004 John Wiley & Sons, Ltd. [source]


Phlomis umbrosa root inhibits mast cell-dependent allergic reactions and inflammatory cytokine secretion

PHYTOTHERAPY RESEARCH, Issue 2 2008
Tae-Yong Shin
Abstract The effect of an aqueous extract of Phlomis umbrosa Turcz. (Labiatae) root (PUAE) on mast cell-dependent allergic reactions and inflammatory cytokine secretion were investigated. PUAE (0.01,1 g/kg) inhibited compound 48/80-induced systemic allergic reaction. When PUAE was employed in a systemic allergic reaction test, the plasma histamine levels were reduced in a dose-dependent manner. PUAE (0.1 and 1 g/kg) also significantly inhibited the local allergic reaction activated by anti-dinitrophenyl (DNP) IgE. PUAE (0.001,1 mg/mL) dose-dependently inhibited the histamine release from rat peritoneal mast cells activated by compound 48/80 or anti-DNP IgE. PUAE (0.01,1 mg/mL) inhibited the secretion of interleukin (IL)-1, in phorbol 12-myristate 13-acetate plus calcium ionophore A23187-stimulated human mast cell line (HMC-1) cells. PUAE (1 mg/mL) inhibited the gene expression and production of the main inflammatory cytokine, TNF- ,, in HMC-1 cells. These results provide evidence that PUAE may be beneficial in the treatment of allergic diseases. Copyright © 2007 John Wiley & Sons, Ltd. [source]


Action of,,Rubus coreanus extract on systemic and local anaphylaxis

PHYTOTHERAPY RESEARCH, Issue 6 2002
Tae-Yong Shin
Abstract The effect was investigated of the aqueous extract of Rubus coreanus Miq. (Rosaceae) fruits (RCAE) on systemic and local anaphylaxis. RCAE (0.01,1,g/kg) dose-dependently inhibited systemic anaphylaxis induced by compound 48/80 in mice. RCAE (1,g/kg) also significantly inhibited local anaphylaxis activated by anti-DNP IgE. Pretreatment with RCAE at the same concentration before systemic anaphylaxis reduced the plasma histamine levels in a dose-dependent manner. RCAE (0.001,1,mg/mL) dose-dependently inhibited the histamine release from rat peritoneal mast cells (RPMC) activated by compound 48/80 or anti-DNP IgE. The level of cAMP in RPMC, when RCAE was added, significantly increased, compared with that of the normal control. Moreover, RCAE,(0.01,1,mg/mL) had a significant inhibitory effect on anti-DNP IgE-induced tumour necrosis factor-, production from RPMC. These results indicate that RCAE may possess antianaphylactic action. Copyright © 2002 John Wiley & Sons, Ltd. [source]


Melectin: A Novel Antimicrobial Peptide from the Venom of the Cleptoparasitic Bee Melecta albifrons

CHEMBIOCHEM, Issue 17 2008
Václav, ovský Dr.
Abstract A novel antimicrobial peptide designated melectin was isolated from the venom of the cleptoparasitic bee Melecta albifrons. Its primary sequence was established as H-Gly-Phe-Leu-Ser-Ile-Leu-Lys-Lys-Val-Leu-Pro-Lys-Val-Met-Ala-His-Met-Lys-NH2 by Edman degradation and ESI-QTOF mass spectrometry. Synthetic melectin exhibited antimicrobial activity against both Gram-positive and -negative bacteria and it degranulated rat peritoneal mast cells, but its hemolytic activity was low. The CD spectra of melectin measured in the presence of trifluoroethanol and sodium dodecyl sulfate showed a high content ,-helices, which indicates that melectin can adopt an amphipathic ,-helical secondary structure in an anisotropic environment such as the bacterial cell membrane. To envisage the role of the proline residue located in the middle of the peptide chain on biological activity and secondary structure, we prepared several melectin analogues in which the Pro11 residue was either replaced by other amino acid residues or was omitted. The results of biological testing suggest that a Pro kink in the ,-helical structure of melectin plays an important role in selectivity for bacterial cells. In addition, a series of N- and C-terminal-shortened analogues was synthesized to examine which region of the peptide is related to antimicrobial activity. [source]


Blockade of superoxide generation prevents high-affinity immunoglobulin E receptor-mediated release of allergic mediators by rat mast cell line and human basophils

CLINICAL & EXPERIMENTAL ALLERGY, Issue 4 2002
T. Yoshimaru
Summary Background Previous studies have shown that rat peritoneal mast cells and mast cell model rat basophilic leukaemia (RBL-2H3) cells generate intracellular reactive oxygen species (ROS) in response to antigen challenge. However, the physiological significance of the burst of ROS is poorly understood. Objective The present study was undertaken to investigate the role of superoxide anion in mediator release in rat and human cell systems. Methods RBL-2H3 cells were directly stimulated with anti-rat Fc,RI ,-subunit monoclonal antibody (mAb). For the analysis of human cell system, leucocytes were isolated by dextran sedimentation from healthy volunteers or from patients, and challenged either with anti-human Fc,RI mAb or with the relevant antigens. Superoxide generation was determined by chemiluminescence-based methods. The releases of histamine and leukotrienes (LT)s were determined by enzyme-linked immunosorben assay (ELISA). Results Cross-linking of Fc,RI on RBL-2H3 cells or on human leucocytes from healthy donors by the anti-Fc,RI mAb resulted in a rapid generation of superoxide anion, as determined by chemiluminescence using superoxide-specific probes. Similarly, leucocytes from patients generated superoxide anion in response to the challenge with the relevant allergen but not with the irrelevant allergen. Furthermore, diphenyleneiodonium (DPI), a well-known inhibitor of flavoenzymes suppressed the superoxide generation and the release of histamine and LTC4 induced by the anti-Fc,RI mAb or by allergen in parallel. Conclusion These results indicate that both RBL-2H3 cells and human basophils generate superoxide anion upon Fc,RI cross-linking either by antibody or by allergen challenge and that blockade of the generation prevents the release of allergic mediators. The findings strongly support the role of superoxide generation in the activation of mast cells and basophils under both physiological and pathological conditions. The findings suggest that drugs regulating the superoxide generation have potential therapeutic use for allergic disorders. [source]