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S J Galli

Publications and source records attributed to S J Galli.

At least 73 records · Page 4Linked to original sources
PubMed1996

Salivary EGF regulates eosinophil-derived TGF-alpha expression in hamster oral wounds.

Using hamster as an oral wound healing model, we examined eosinophils and their expression of transforming growth factor-alpha (TGF-alpha) and transforming growth factor-beta 1 (TGF-beta 1). Oral wounds healed approximately two times faster than their cutaneous counterparts. Eosinophils infiltrated prominently into oral wounds; however, unlike the dual expression of TGF-alpha and TGF-beta 1 in skin wounds, oral wound-associated eosinophils expressed TGF-beta 1, but not TGF-alpha. Because saliva is present in oral environments and contains epidermal growth factor (EGF) and TGF-alpha, sialoadenectomy was performed in this model to determine whether the lack of TGF-alpha expression by eosinophils in oral wounds is due to the presence of salivary EGF and/or TGF-alpha. We found that eosinophils in sialoadenectomized hamsters did express TGF-alpha during oral wound healing but that such expression was suppressed when EGF was added to their drinking water. Taken together, our findings suggest that eosinophil-derived TGF-alpha and salivary TGF-alpha/ EGF may have complementary roles in contributing to TGF-alpha in oral wound healing.

Animals↗
PubMed1996

Tumor necrosis factor alpha immunoreactivity of rat peritoneal mast cell granules decreases during early secretion induced by compound 48/80: an ultrastructural immunogold morphometric analysis.

We used fast (seconds) and ultrafast (milliseconds) microwave energy-assisted chemical fixation protocols, postembedding immunogold staining, and a morphometric analysis to investigate the early morphological changes and the TNF-alpha immunoreactivity in the cytoplasmic granules of rat peritoneal mast cells that had been stimulated to secrete by exposure to compound 48/80. Exposure to compound 48/80 induced the development of increased numbers of cytoplasmic granules that exhibited decreased electron density; these granules often also appeared swollen. These granule alterations were accompanied by a significantly decreased proportion of granules that were positive for TNF-alpha immunoreactivity. We also calculated the density of TNF-alpha labeling/mu 2 in both dense (unaltered) and altered granules in specimens. TNF-alpha immunoreactivity was present in dense granules (regardless of whether or not the specimens had been stimulated with compound 48/80) and in cells that were fixed with either fast or ultrafast microwave energy. However, altered granules exhibited a decreased density of TNF-alpha label. These findings show that changes in the immunolocalization and/or density of TNF-alpha immunoreactivity occur very rapidly upon stimulation of rat peritoneal mast cells with compound 48/80.

Animals↗
PubMed1996

TNF alpha is important in human lung allergic reactions.

Tumor necrosis factor alpha (TNF alpha) is a potentially important cytokine in allergic respiratory reactions since it is released by mast cells and eosinophils, and it can promote mediator and cytokine release, adhesion molecule expression, and granulocyte migration. Therefore, we induced an IgE-mediated response in human lung samples and studied: (1) whether TNF alpha was produced in sufficient quantities to promote granulocyte migration; and (2) which cells expressed mRNA for TNF alpha using in situ hybridization. Lung fragments (from thoracotomy) were treated for 30 min with either anti-IgE, 1:100 dilution, or buffer (control). Anti-IgE treatment of 16 lungs resulted in greater than 4-fold increase in histamine release and the significant production of chemotactic activity. The chemotactic activity generated induced dose-responsive neutrophil and eosinophil migration through naked filters and endothelial and pulmonary epithelial monolayers. Fourteen of 16 samples had a significant increase in TNF alpha subsequent to anti-IgE treatment (P < 0.05). Anti-TNF alpha antibody (4 micrograms/ml) inhibited about 25% of the neutrophil chemotactic activity in supernatants from anti-IgE treated lungs. TNF alpha at a concentration measured after anti-IgE treatment of lung samples (50 pg/ml) induced neutrophil transendothelial migration. Finally, we found that anti-IgE treatment led to an increase in TNF alpha mRNA-positive cells by in situ hybridization (1.6/ mm2 experimental versus 0.5/mm2 control), some of which were eosinophils. Thus, human lung IgE-mediated responses in vitro results in: (1) release of TNF alpha in amounts sufficient to effect a biologic response, granulocyte chemotaxis: and (2) upregulation of mRNA for TNF alpha in eosinophils and other cells. These findings suggest that TNF alpha is an important effector molecule in the pathogenesis of allergic respiratory reactions.

Cell Line↗
PubMed1995

Stem cell factor contributes to intestinal mucosal mast cell hyperplasia in rats infected with Nippostrongylus brasiliensis or Trichinella spiralis, but anti-stem cell factor treatment decreases parasite egg production during N brasiliensis infection.

We assessed the effects of the c-kit ligand, stem cell factor (SCF), in the jejunal mucosal mast cell hyperplasia that occurs during infection with the intestinal nematodes, Nippostrongylus brasiliensis or Trichinella spiralis in rats. Compared with vehicle-treated rats, rats treated with SCF (25 micrograms/kg/d, intravenous [i.v.] for 14 days) during N brasiliensis infection exhibited significantly higher levels of the rat mucosal mast cell (MMC)-associated protease, rat mast cell protease II (RMCP II) in the jejunum and serum on day 8 of infection, but not on days 10 or 15 of infection. By contrast, in comparison to rats treated with normal sheep IgG, rats treated with a polyclonal sheep antirat SCF antibody exhibited markedly decreased numbers of jejunal MMCs, levels of jejunal RMCP II, and serum concentrations of RMCP II during infection with either nematode, particularly at the earlier intervals of infection (< or = day 10). Taken together, these findings indicate that SCF importantly contributes to MMC hyperplasia and/or survival during N brasiliensis or T spiralis infection in rats, but that levels of endogenous SCF are adequate to sustain near maximal MMC hyperplasia during infection with these nematodes. Notably, treatment of rats with SCF somewhat increased, and treatment with anti-SCF significantly decreased, parasite egg production during N brasiliensis infection. This finding raises the interesting possibility that certain activities of intestinal MMCs may contribute to parasite fecundity during infection with this nematode.

Analysis of Variance↗
PubMed1995

Dexamethasone or cyclosporin A suppress mast cell-leukocyte cytokine cascades. Multiple mechanisms of inhibition of IgE- and mast cell-dependent cutaneous inflammation in the mouse.

In allergic diseases, exposure of sensitized subjects to allergen induces the activation of tissue mast cells that results in an immediate-type hypersensitivity response and, in some individuals, a a late phase response. We previously have reported that the neutrophil infiltration associated with IgE-dependent cutaneous inflammation in mice is mast cell-dependent and that TNF-alpha contributes significantly to this response. We report here that either dexamethasone or cyclosporin A can inhibit mouse mast cell TNF-alpha production in vitro, and that these agents also can significantly suppress the tissue swelling and leukocyte infiltration associated with two forms of TNF-alpha-associated inflammation in vivo: the entirely IgE- and mast cell-dependent inflammation at sites of passive cutaneous anaphylaxis reactions and the entirely TNF-alpha-dependent inflammation that is elicited by the direct intradermal injection of recombinant mouse TNF-alpha. Taken together, our in vitro and in vivo findings in mice indicate that dexamethasone or cyclosporin A can have at least three actions that interfere with the pathogenesis of IgE, mast cell, and cytokine-dependent inflammatory reactions:suppression of the IgE-dependent increase in TNF-alpha mRNA by mast cells, inhibition of the IgE-dependent production of TNF-alpha protein by mast cells, and diminution of the responsiveness of target cells to TNF-alpha. Our findings in mice raise the possibility that similar actions of these agents in humans may account for some of the clinical efficacy of corticosteroids and cyclosporin A in allergic diseases.

Animals↗
PubMed1995

Ultrastructural immunogold localization of subcellular sites of TNF-alpha in colonic Crohn's disease.

Tumor necrosis factor-alpha, a proinflammatory cytokine, might have an important role(s) in initiating, modifying, and/or sustaining chronic inflammatory processes such as those that characterize Crohn's disease, an inflammatory bowel disease of unknown etiology. We used an immunogold ultrastructural morphometric approach to localize tumor necrosis factor-alpha in colonic Crohn's disease biopsies. Tumor necrosis factor-alpha was present in seven cell types (fibroblasts, eosinophils, mast cells, macrophages, colonic epithelial absorptive cells, Paneth cells, neutrophils). Tumor necrosis factor-alpha-containing subcellular organelles included lipid bodies (fibroblasts, eosinophils, macrophages, mast cells, colonic epithelial cells, neutrophils), secretory granules (eosinophils, Paneth cells), phagolysosomes (macrophages, colonic epithelial cells), and Golgi structures and vesicle membranes (neutrophils). A gradient of extracellular tumor necrosis factor-alpha immunoreactivity surrounded eosinophils, mast cells, and macrophages. P values of gold counts/microns2 were significant for all cells, organelles, and extracellular spaces measured, and all positive structures significantly exceeded the background labeling density/microns2. Specificity controls (normal rabbit serum, tumor necrosis factor-alpha-absorbed primary antibody) either failed to label these sites or gave markedly reduced specific tumor necrosis factor-alpha labeling, respectively. These findings represent the first ultrastructural localization of the subcellular sites of TNF-alpha in vivo in seven cell lineages in human colonic tissues.

Adult↗
PubMed1995

Mouse mast cell cytokine production: rôle in cutaneous inflammatory and immunological responses.

The rôle of mast cells in cutaneous physiology and pathology has long been a subject of intense speculation and great clinical interest. In this brief review, which is focused primarily on murine systems, we outline certain important aspects of the biology of the mast cell, including their ability to produce a variety of cytokines, describe the development of a model system (the "mast cell knock-in mouse") for studying the roles of cutaneous mast cells in biological responses in vivo, and illustrate a few examples of how this approach has been used to investigate the contributions of mast cells and their cytokines to cutaneous inflammatory or immune responses.

Animals↗
PubMed1995

Substance P induces ion secretion in mouse small intestine through effects on enteric nerves and mast cells.

We used genetically mast cell-deficient WBB6F1 W/Wv (W/Wv) mice and congenic WBB6F1 +/+ normal (+/+) mice to examine the role of mast cells in substance P-induced intestinal ion secretion. Isolated sheets prepared from segments of the midportion of the small intestine were studied in Ussing chambers. Substance P caused a dose-dependent increase in short-circuit current (Isc) that was approximately 50% less in intestine from W/Wv than from +/+ mice. Similar results were obtained for substance P-(4-11) (the COOH terminus) and substance P methyl ester [a selective neurokinin (NK)-1 agonist]. Histamine H1 or H2 antagonists reduced the Isc responses to substance P in intestine from +/+ mice but had no effect in intestine from W/Wv mice. In addition, reconstitution of intestinal mast cells in W/Wv mice by intravenous injection of +/+ bone marrow cells normalized the tissues' secretory responses to substance P or substance P methyl ester. However, in W/Wv and +/+ mice, the selective NK1 antagonist CP-96345 virtually abolished intestinal responses to substance P, and the responses were also markedly inhibited by neural blockade with tetrodotoxin. In contrast, in tetrodotoxin-pretreated intestine, histamine antagonism caused a further reduction in the responses to substance P only in +/+ mouse tissues. Taken together, our results suggest that the effects of substance P on intestinal Isc KN1 receptors but that the neuropeptide acts via effects on enteric nerves and mast cells. The data thus support the concept that mast cells and enteric nerves participate in the regulation of substance P-induced intestinal ion secretion.

Animals↗
PubMed1995

Detection of mouse mast cell-associated protease mRNA. Heparinase treatment greatly improves RT-PCR of tissues containing mast cell heparin.

The reverse transcriptase polymerase chain reaction (RT-PCR) procedure is markedly inhibited in specimens of blood that contain commercial heparin as an anticoagulant or in cell preparations containing rat or mouse peritoneal mast cells. However, it was not known whether the levels of endogenous, mast cell-associated heparin that are present in some mammalian tissues are sufficient to interfere with the use of RT-PCR in these settings. We show that RT-PCR detects little or no mRNA transcripts for either mast cell-associated products, such as mouse mast cell-associated protease-2 or -4 (MMCP-2 or MMCP-4) or mast cell carboxypeptidase A, or for mast cell-nonspecific products, such as glyceraldehyde 3-phosphate dehydrogenase, in routinely prepared specimens of cells or tissues that include populations of heparin-containing mast cells. However, signals for mast cell-associated or mast cell-nonspecific transcripts can be readily detected in such specimens if they are treated with heparinase before RT-PCR. RT-PCR after heparinase treatment appears to represent an extremely sensitive method for detecting mast cell-associated transcripts in tissue specimens, permitting the identification of transcripts for mast cell-specific proteases in the skin of genetically mast cell-deficient WBB6F1-W/WV mice, a tissue that contains few or no mast cells according to histological analysis.

Animals↗
PubMed1995

Stem-cell factor, the kit ligand, induces direct degranulation of rat peritoneal mast cells in vitro and in vivo: dependence of the in vitro effect on period of culture and comparisons of stem-cell factor with other mast cell-activating agents.

We report that stem-cell factor (SCF), the ligand of the receptor encoded by the c-kit proto-oncogene, is a potent activator of degranulation of rat peritoneal mast cells in vitro and in vivo. Freshly isolated, purified mast cells were relatively unresponsive to SCF (4-500 ng/ml) but progressively acquired responsiveness to this agent, assessed as serotonin (5-HT) release, during 48 hr culture in vitro. The cells showed a similar kinetic pattern of acquisition of responsiveness to anti-IgE but responded fully to calcium ionophore A23187 or compound 48/80 regardless of time in culture. Acquisition of mast cell responsiveness to SCF or anti-IgE was not due to serum factors or to recovery from the Percoll purification procedure. During culture, mast cell expression of the SCF receptor (SCFR) increased, and this may explain in part the increased responsiveness to SCF. However, surface IgE expression remained constant, and the increased responses to anti-IgE therefore must reflect changes in components of the secretion-coupling pathway that are activated subsequent to IgE cross-linking. The unresponsiveness of freshly isolated peritoneal mast cells to SCF or anti-IgE does not reflect a state of in vivo unresponsiveness, as peritoneal mast cells degranulated in vivo in response to these agents. We conclude that in terms of their responsiveness to SCF or anti-IgE, cultured tissue mast cells may be more representative than freshly isolated mast cells of secretory function in vivo, and therefore may be more appropriate for physiological or pharmacological studies of SCF- or IgE-dependent secretory responses.

Animals↗
PubMed1994

Promotion of mouse fibroblast collagen gene expression by mast cells stimulated via the Fc epsilon RI. Role for mast cell-derived transforming growth factor beta and tumor necrosis factor alpha.

Chronic allergic diseases and other disorders associated with mast cell activation can also be associated with tissue fibrosis, but a direct link between mast cell mediator release and fibroblast collagen gene expression has not been established. Using in situ hybridization, we show that the elicitation of an IgE-dependent passive cutaneous anaphylaxis (PCA) reaction in mice results in a transient, but marked augmentation of steady state levels of type alpha-1 (I) collagen mRNA in the dermis. While peak levels of collagen mRNA expression in the skin are observed 16-24 h after mast cell activation, substantial numbers of dermal cells are strongly positive for collagen mRNA at 1 and 2 h after antigen challenge, before circulating inflammatory cells are recruited into the tissues. Furthermore, experiments in mast cell-reconstituted or genetically mast cell-deficient WBB6F1-W/Wv mice demonstrate that the increased expression of collagen mRNA at sites of PCA reactions is entirely mast cell dependent. In vitro studies show that the supernatants of mouse serosal mast cells activated via the Fc epsilon RI markedly increase type alpha-1 (I) collagen mRNA levels in mouse embryonic skin fibroblasts, and also upregulate collagen secretion by these cells. The ability of mast cell supernatants to induce increased steady state levels of collagen mRNA in mouse skin fibroblasts is markedly diminished by absorption with antibodies specific for either of two mast cell-derived cytokines, transforming growth factor beta (TGF-beta 1) or tumor necrosis factor alpha (TNF-alpha), and is eliminated entirely by absorption with antibodies against both cytokines. Taken together, these findings demonstrate that IgE-dependent mouse mast cell activation can induce a transient and marked increase in steady state levels of type alpha-1 (I) collagen mRNA in dermal fibroblasts and that mast cell-derived TGF-beta 1 and TNF-alpha importantly contribute to this effect.

Animals↗
PubMed1994

Piecemeal degranulation of mast cells in the inflammatory eyelid lesions of interleukin-4 transgenic mice. Evidence of mast cell histamine release in vivo by diamine oxidase-gold enzyme-affinity ultrastructural cytochemistry.

We used light and electron microscopy to analyze the eyelid inflammation that develops in transgenic mice that overexpress interleukin-4 (IL-4; Tepper et al, Cell 62:457, 1990). Analysis of alkaline Giemsa-stained plastic sections examined by light microscopy (Dvorak et al, J Exp Med 132:558, 1970), as well as by routine transmission electron microscopy, indicated that the mast cells in the inflammatory eyelid lesions were undergoing piecemeal degranulation, a form of secretion in which the cells' cytoplasmic granules exhibit characteristic morphologic changes that are thought to be associated with the prolonged, vesicle-mediated release of the granules' constituents. Moreover, by using a newly reported enzyme affinity-gold method, which stains histamine based on binding to diamine oxidase-gold (Dvorak et al, J Histochem Cytochem 41:787, 1993), we show that these activated mast cells had released much of their histamine content. The eyelid lesions also exhibited increased numbers of mast cells; interstitial fibrosis, particularly around cutaneous nerves and blood vessels; activated fibroblasts; focal axonal damage; venules with endothelial cells containing numerous vesiculo-vacuolar organelles; and infiltrates of neutrophils and eosinophils. Our findings illustrate that overexpression of the IL-4 gene in vivo can result in eyelid lesions associated with piecemeal degranulation of mast cells, as well as tissue fibrosis and a variety of other pathologic changes. These results also represent the first direct morphologic evidence for histamine secretion by mast cells in vivo.

Amine Oxidase (Copper-Containing)↗
PubMed1994

Mast cells augment lesion size and persistence during experimental Leishmania major infection in the mouse.

Mast cells are a source of a variety of cytokines that may influence the host response to Leishmania major. To investigate the role of mast cells during L. major infection, we performed a morphometric analysis of mast cells at cutaneous sites in resistant C57BL/6 mice and susceptible BALB/c mice injected with L. major. Extensive dermal mast cell degranulation was found at sites of L. major infection in both strains of mice. We also examined the course of L. major infection in genetically mast cell-deficient WBB6F1-W/Wv or WCB6F1-Sl/Sld mice, their respective congenic normal (WBB6F1-(+/+) or WCB6F1-(+/+)) littermates, and WBB6F1-W/Wv mice that had been selectively and locally repaired of their cutaneous mast cell deficiency. We found that mast cells significantly augmented the intensity and maximal size of the cutaneous lesions at sites of L. major infection, and in some cases substantially prolonged the persistence of the reactions. However, the lesions ultimately resolved in both the mast cell-deficient and the congenic normal mice. In addition, the presence or absence of mast cells had little or no effect on the numbers of viable parasites recovered from the cutaneous lesions. Moreover, mast cell-deficient W/Wv mice and the congenic normal (+/+) mice produced similar levels of IFN-gamma mRNA in lymph nodes draining the cutaneous lesions whereas no IL-4 mRNA was detectable. Taken together, these data suggest that mast cells significantly augment the size of cutaneous lesions during L. major infection in mice. However, mast cells do not appear to influence significantly either the parasite burden or the ultimate resolution of the infection.

Animals↗
PubMed1994

Effects of stem cell factor (kit-ligand) and interleukin-3 on the growth and serine proteinase expression of rat bone-marrow-derived or serosal mast cells.

The effects of rat stem-cell factor (SCF) and interleukin-3 (IL-3), alone or in combination, on the in vitro growth and serine proteinase expression of rat serosal/connective-tissue mast cells (CTMC) or bone marrow-derived mast cells (BMMC) were examined. Rat SCF stimulated the growth of both CTMC and BMMC. IL-3 stimulated BMMC growth to a lesser extent than did SCF, whereas CTMC numbers did not increase in IL-3. However, SCF and IL-3 had synergistic effects on the growth of both BMMC and CTMC. SCF favoured the maintenance of rat mast cell proteinase-I (RMCP-I) in CTMC, but did not induce detectable production of RMCP-I in BMMC. In contrast, when IL-3 or lymph node-conditioned medium (LNCM) was added to SCF, a subpopulation of CTMC expressed and stored the soluble proteinase RMCP-II. In BMMC, the RMCP-II content of cells maintained in SCF was significantly less than that of cells maintained in IL-3 or LNCM. RMCP-II also appeared in the supernatants of BMMC, especially when BMMC numbers were increasing rapidly in SCF with or without IL-3 or LNCM. Thus, SCF and IL-3 can regulate the growth of rat BMMC and CTMC, as well as influence their production and release of proteinases.

Animals↗
PubMed1994

Cytoplasmic granule formation in mouse pancreatic acinar cells. Evidence for formation of immature granules (condensing vacuoles) by aggregation and fusion of progranules of unit size, and for reductions in membrane surface area and immature granule volume during granule maturation.

We used a computer-assisted morphometry approach to analyze quantitatively the process of cytoplasmic granule formation in mouse pancreatic acinar cells stimulated with pilocarpine to induce secretion. Our findings suggest that each condensing vacuole/immature granule of pancreatic acinar cells is formed by the progressive aggregation of 106 to 128 "unit progranules" of narrowly fixed volume, define a range of 7.7 to 9.2 for the factor of volume condensation between the largest immature granules and the mature unit granule, and predict that the formation of a single mature unit granule by the aggregation and fusion of unit progranules involves a net reduction of at least 95% in the amount of membrane surface area associated with these structures.

Animals↗
PubMed1994

Ultrastructural immunogold localization of tumor necrosis factor-alpha to the cytoplasmic granules of rat peritoneal mast cells with rapid microwave fixation.

Tumor necrosis factor-alpha (TNF-alpha) is a multifunctional, proinflammatory cytokine, which can be produced by mast cells and several other cell types. We used a newly developed microwave energy-assisted aldehyde fixation method to prepare purified rat peritoneal mast cells for the postembedding immunogold ultrastructural localization of TNF-alpha. These fixation methods were superior to chemical fixation alone in preserving both the ultrastructural morphology and immunoreactive TNF-alpha in rat mast cells. The percent of TNF-alpha-positive mast cells in samples prepared with microwave-assisted fixation in low (84%) and standard (81%) glutaraldehyde concentrations exceeded that for low (56%) and standard (15%) glutaraldehyde concentrations without the assistance of microwave energy. TNF-alpha was identified in the large storage granules of rat mast cells. The percent of positive granules in microwave-assisted standard (44%) and low (40%) glutaraldehyde samples was considerably higher than the percent of positive granules in standard (5%) and low (10%) glutaraldehyde-fixed samples without microwave assistance. This location of TNF-alpha in rat peritoneal mast cells suggests that this cytokine can use the regulated secretory route(s) for release from appropriately stimulated rat mast cells into the microenvironment.

Animals↗