NOD1 and NOD2 Interact with the Phagosome Cargo in Mast Cells: A Detailed Morphological Evidence.

Mast cells (MC) play a key role in triggering the inflammatory process and share some functions with professional phagocytes. It is not clear whether or not the phagocytic process in MC follows the same route and has the same meaning of that of professional phagocytes. Herein we analyze in detail the structure of the phagosome in rat peritoneal mast cells (RPMC).

Mast cells kill Candida albicans in the extracellular environment but spare ingested fungi from death.

Mast cells (MCs) reside in tissues that are common targets of Candida spp. infections, and can exert bactericidal activity, but little is known about their fungicidal activity. MCs purified from rat peritoneum (RPMC) and a clinical isolate of C.

Munc18-2 and syntaxin 3 control distinct essential steps in mast cell degranulation.

Mast cell degranulation requires N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) and mammalian uncoordinated18 (Munc18) fusion accessory proteins for membrane fusion. However, it is still unknown how their interaction supports fusion. In this study, we found that small interfering RNA-mediated silencing of the isoform Munc18-2 in mast cells inhibits cytoplasmic secretory granule (SG) release but not CCL2 chemokine secretion.

The crocidolite fibres interaction with human mesothelial cells as investigated by combining electron microscopy, atomic force and scanning near-field optical microscopy.

In this study, we have performed a morphological analysis of crocidolite fibres interaction with mesothelial cells (MET5A) by combining conventional electron microscopy with atomic force (AFM) and scanning near-field optical microscopy (SNOM). After 6-h exposure at a crocidolite dose of 5 μg cm(-2), 90% of MET5A cells interact with fibres that under these conditions have a low cytotoxic effect. SEM images point out that fibres can be either engulfed by the cells that lose their typical morphology or they can accumulate over or partially inside the cells, which preserve their typical spread morphology.

Influence of FAS on murine mast cell maturation.

Background: FAS has been shown to be involved in the regulation of many immune processes by induction of cellular apoptosis. However, accumulated evidence shows that FAS signaling also exhibits nonapoptotic functions, such as induction of cell proliferation and differentiation. FAS is the only death receptor known to be expressed on murine mast cells (MCs).

BCG prophylaxis in bladder cancer produces activation of recruited neutrophils.

Introduction: Bacillus Calmette-Guerin (BCG) is used to treat high risk superficial bladder cancer, but its anti-tumor effect remains incompletely defined. Recently a role for polymophonuclear (PMN) neutrophils has been suggested. To investigate the role of granulocytes, we monitored the activation state of these cells in the urine of BCG-treated patients.

Ultrastructural evidence for human mast cell-eosinophil interactions in vitro.

We have hypothesized that mast cells (MC) and eosinophils (Eos), the main effectors of allergy, can form an effector unit. These cells co-exist in the inflamed tissues during the late and chronic stages of allergy and have been shown to be capable of influencing each other's survival and activity via soluble mediators. We have recently described couples of receptor-ligands that are expressed on either/both of these cells and that imply a physical interaction.

Mast cell adhesion induces cytoskeletal modifications and programmed cell death in oligodendrocytes.

In this paper we show that rat peritoneal mast cells (RPMC) adhere to rat oligodendrocytes (ODC) in culture and switch on a bi-directional signal affecting both adhering cell and its target. Following heterotypic interaction, RPMC release granule content and ODC show morphological changes and enter the apoptotic programme. Altogether, these findings indicate that the interaction of MC with ODC could play a role in the mechanism of CNS damage induced by the inflammatory reaction.

Mast cell activation by myelin through scavenger receptor.

A role for mast cells (MC) in the pathogenesis of multiple sclerosis (MS) has been suggested, based on the analysis of human lesions and on an animal model of the disease (EAE). What role MC play in the development of MS is not well understood. We hypothesized that the link connecting MC with demyelinating diseases may be represented by their interaction with myelin.

Involvement of Munc18 isoforms in the regulation of granule exocytosis in neutrophils.

Human neutrophil granule exocytosis mobilizes a complex set of secretory granules. This involves different combinations of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins to facilitate membrane fusion. The control mechanisms governing the late fusion steps are still poorly understood.

VAMP-8 segregates mast cell-preformed mediator exocytosis from cytokine trafficking pathways.

Inflammatory responses by mast cells are characterized by massive exocytosis of prestored granular mediators followed by cytokine/chemokine release. The vesicular trafficking mechanisms involved remain poorly understood. Vesicular-associated membrane protein-8 (VAMP-8), a member of the soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor (SNARE) family of fusion proteins initially characterized in endosomal and endosomal-lysosomal fusion, may also function in regulated exocytosis.

BCG-induced rabbit alveolar macrophages are endowed with strengthened antioxidant metabolic pathways.

Following i.v. BCG infection, a new population of macrophages are recruited in the rabbit lung.

Oral administration of yessotoxin stabilizes E-cadherin in mouse colon.

YTX has been shown to disrupt the E-cadherin-catenin system in cultured epithelial cells, raising some concern that ingestion of seafood contaminated by YTX might favour tumour spreading and metastasis formation in vivo. In order to probe whether YTX might affect cadherin systems in vivo, we have set up a study involving repeated oral dosing of the toxin in mice (1mg/kg/day, for 7 days) and analysis of E-cadherin and N-cadherin in tissue extracts obtained at the end of the dosing scheme, as well as 1 and 3 months after YTX administration. We found that the E-cadherin pools obtained from lung and kidney were not altered by YTX in any of our experimental conditions.

Identification and subcellular localization of neuronal calcium sensor-1 (NCS-1) in human neutrophils and HL-60 cells.

Secretion in neutrophils is thought to be regulated in different ways for the different granule types. Specific granules are endowed with proteins which are related to docking and fusion events and are absent on azurophilic granules. Furthermore, even if secretion of content from all neutrophil granules is a Ca(2+)-dependent process, a higher concentration of cytosolic calcium is required for azurophilic than for specific granule secretion.

Dual Action of NAMI-A in inhibition of solid tumor metastasis: selective targeting of metastatic cells and binding to collagen.

NAMI-A is a ruthenium complex endowed with a selective effect on lung metastases of solid metastasizing tumors. The aim of this study is to provide evidence that NAMI-A's effect is based on the selective sensitivity of the metastasis cell, as compared with other tumor cells, and to show that lungs represent a privileged site for the antimetastatic effects. The transplantation of Lewis lung carcinoma cells, harvested from the primary tumor of mice treated with 35 mg/kg/day NAMI-A for six consecutive days, a dose active on metastases, shows no change in primary tumor take and growth but a significant reduction in formation of spontaneous lung metastases.

Human eosinophil peroxidase induces surface alteration, killing, and lysis of Mycobacterium tuberculosis.

The antimycobacterial role of eosinophil peroxidase (EPO), one of the most abundant granule proteins in human eosinophils, was investigated. Our data indicate that purified EPO shows significant inhibitory activity towards Mycobacterium tuberculosis H37Rv. On a molar basis, this activity was similar to that exhibited by neutrophil myeloperoxidase (MPO) and was both dose and time dependent.

Ultrastructure of the interaction between mycobacterium tuberculosis- H37Rv-containing phagosomes and the lysosomal compartment in human alveolar macrophages.

The ultrastructure of the interaction between the lysosomal compartment and the Mycobacterium tuberculosis-containing phagosomes in human resident alveolar macrophages has been analyzed in detail. Our findings confirm the widely accepted notion that the parasitophore vacuole is made nonfusogenic by the microorganism; however, the association between the lysosomal compartment and the phagosomes does not seem to be impaired as the organelles were shown to spread around the ingested pathogen. Furthermore, interruptions in the phagosome membrane that connect the bacterial surface with the cytosol were observed.

A new assay to monitor the degranulation process in phagocytizing human neutrophils.

oxidation, we set up a method for measuring MPO intraphagosomal release in human neutrophils. The method is based on the passive engulfment of DAB together with the phagocytosable particle. Inside the vacuole, this substrate is oxidized by MPO released from the azurophilic granules.