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Biomedical subjects

S J Galli

Publications and source records attributed to S J Galli.

At least 91 records · Page 5Linked to original sources
PubMed1994

Expression of transforming growth factors-alpha and beta 1 messenger RNA and product by eosinophils in nasal polyps.

Nasal polyps are thought to develop as a manifestation of a chronic inflammatory process involving the upper airways. The eosinophil characteristically represents a prominent component of the inflammatory cell infiltrate of these lesions. However, the major clinical problem associated with nasal polyps, nasal obstruction, reflects the proliferation of the stromal and epithelial elements, which constitute the bulk of these lesions. We recently reported that blood eosinophils of patients with hypereosinophilia can produce the cytokines transforming growth factors-alpha (TGF-alpha) and beta 1 (TGF-beta 1). These cytokines have many biologic activities, which include the regulation of epithelial proliferation, the promotion of extracellular matrix formation, and the induction of angiogenesis. We therefore used in situ hybridization to determine whether the eosinophils that infiltrate nasal polyps express TGF-alpha and/or TGF-beta 1 messenger RNA and used immunohistochemistry to determine whether these eosinophils also express TGF-alpha and TGF-beta 1 proteins. We found that eosinophils represented a major source of both transforming growth factors in each case of nasal polyposis examined and that in most cases the majority of all eosinophils expressed both TGF-alpha and TGF-beta 1. These results suggest that production of TGF-alpha and TGF-beta 1 by the infiltrating eosinophils may contribute to some of the pathologic changes observed in nasal polyposis, such as thickening of the epithelial basement membrane, stromal fibrosis, angiogenesis, and epithelial and glandular hyperplasia.

Aniline Compounds↗
PubMed1994

Identification of IgE-bearing cells in the late-phase response to antigen in the lung as basophils.

We have carried out studies to ascertain whether the histamine-containing, IgE-bearing cells found in the bronchoalveolar lavage (BAL) fluid obtained during the late-phase response following subsegmental antigen challenge of human airways are predominantly basophils or mast cells. Four lines of evidence suggest that most are basophils: (1) The cells fulfill morphologic criteria for light microscopy. (2) Cell surface markers determined by immunofluorescence and flow cytometry revealed that the IgE-bearing cells express the leukocyte antigens Fc gamma RII and the beta 2 integrins, LFA-1 and Mac-1, but do not express the mast cell-associated c-kit receptor for stem cell factor. (3) The late-phase histamine-containing cells in late-phase BAL fluids have the functional characteristics of basophils in their secretory responses to anti-IgE, the f-met peptide, and phorbol ester TPA. (4) The cells have a functional histamine type 2 receptor, a characteristic of basophils, not mast cells. We conclude that basophils infiltrate the lower airways hours after antigen exposure. These cells may be responsible for the mediator release observed at that time.

Alcian Blue↗
PubMed1994

Effects of interleukin-3 with or without the c-kit ligand, stem cell factor, on the survival and cytoplasmic granule formation of mouse basophils and mast cells in vitro.

We assessed the ultrastructure and the cell-surface expression of receptors for immunoglobulin E (Fc epsilon R), and c-kit, the receptor for stem cell factor (SCF), in mouse basophils and mast cells present in short-term cultures of mouse bone marrow cells in interleukin-3 (IL-3) with or without SCF. Basophils did not develop increased numbers of cytoplasmic granules and underwent apoptosis in cultures containing IL-3 and SCF, whereas mast cells thrived and developed increased numbers of granules. Basophils were nearly all Fc epsilon R+ c-kit- when sorted after culture in IL-3 and SCF; most mast cells were Fc epsilon R+ c-kit+. However, a second population of Fc epsilon R+ c-kit- mast cells was present after culture in IL-3 and SCF. These c-kit receptor-negative mast cells were less mature than c-kit+ mast cells and contained significantly fewer cytoplasmic granules than the c-kit+ mast cells present in the same cultures (P < 0.001). Thus, mouse basophils express little or no c-kit receptor on their surface, nor can they survive for long periods in SCF-supplemented cultures. By contrast, mouse mast cells seem to express the Fc epsilon R early in their development, even before they express detectable c-kit receptors on their surface. IL-3 promotes cytoplasmic granule formation in immature mast cells, but even more granules are formed when c-kit receptor-positive immature mast cells are cultured in both SCF and IL-3.

Animals↗
PubMed1994

The c-kit ligand, stem cell factor, promotes mast cell survival by suppressing apoptosis.

Stem cell factor (SCF) and its receptor (SCFR), a member of the receptor tyrosine kinase III family that is encoded by the c-kit gene, critically regulate several complex biological programs including hematopoiesis, mast cell development, cutaneous pigmentation, and gametogenesis. We show herein that mouse mast cells die rapidly after the withdrawal of SCF in vivo or in vitro, and provide morphological evidence that such mast cells undergo programmed cell death or apoptosis. We also show that when in vitro-derived mouse mast cells maintained in SCF are removed from SCF-containing medium for only 5 or 6 hours, the cells' genomic DNA exhibits the ladder-like pattern of oligonucleosome-sized fragments typical of apoptosis. These findings demonstrate that SCF can regulate the survival of a cellular lineage which expresses the SCFR by suppressing apoptosis. They also identify a mechanism that can result in striking and rapid reductions in the size of tissue mast cell populations without histological evidence of the concomitant induction of a significant inflammatory response.

Animals↗
PubMed1994

Mast cell and basophil development.

Mast cells and basophils express certain remarkable similarities in mediator content, histochemical characteristics, and function. Yet a large body of evidence now indicates that the mast cell and basophil lineages are distinct. Stem cell factor, the ligand for the receptor encoded by c-kit, is a major growth factor for mast cells in both rodent and primate species, and can modulate mast cell secretory function. Moreover, abnormalities affecting the stem cell factor receptor or stem cell factor might contribute to some cases of mastocytosis or mast cell neoplasms. By contrast, basophils can develop independently of stem cell factor, and are not as sensitive as mast cells to the effects of stem cell factor on mediator secretion. In addition, the cytokine interleukin-3 greatly augments the production of human basophils, but has little or no growth promoting activity for human mast cells.

Animals↗
PubMed1993

Variants of vasoactive intestinal peptide in mouse mast cells and rat basophilic leukemia cells.

Radioimmunoassays for neuroendocrine vasoactive intestinal peptide (VIP1-28) detected 30-120 fmol of structurally related peptides in extracts of 10(7) mouse peritoneal mast cells, bone marrow-derived mast cells, cultured PT-18 and C1.MC/C57.1 lines of mast cells, and rat basophilic leukemia (RBL) cells. No VIP was found in peritoneal cells of mast cell-deficient WBB6F1-W/Wv mice, whereas the amounts extracted from peritoneal cells of the congenic normal (WBB6F1-+/+) mice were similar to those from cultured mouse mast cells. Sephadex G-25 gel filtration resolved two different-sized variants of VIP from mouse mast cells and RBL cells. Amino acid sequence analyses showed that the smaller variant is VIP10-28. The principal amino-terminally larger variant of VIP from C1.MC/C57.1 mouse mast cells and RBL cells exhibited amino acid sequence homology with VIP(-6)-28, and this sequence was established for the corresponding larger VIP from PT-18 mast cells. Polymerase chain reaction amplification of two different substituent sequences of prepro VIP in RBL cell RNA identified the VIP message. VIP10-28 was released from mouse mast cells concurrently with histamine by IgE-dependent stimulation. Rodent mast cell-derived VIP thus consists of both the truncated VIP10-28 and amino-terminally larger forms that appear to be generated by peptidolysis of a preproVIP similar to that found in neural cells.

Amino Acid Sequence↗
PubMed1993

Mast cells contribute to the changes in heart rate, but not hypotension or death, associated with active anaphylaxis in mice.

The mast cell is widely thought to contribute importantly to the cardiopulmonary changes associated with anaphylaxis, but much of the evidence for this is indirect. We, therefore, performed a detailed assessment of heart rate and pulmonary function during active anaphylaxis in genetically mast cell-deficient W/Wv or S1/S1d mice, the congenic normal (+/+) mice, and W/Wv mice repaired of their mast cell deficiency by transplantation of bone marrow from the congenic +/+ mice (+/+ BM-->W/Wv mice). For all five groups of mice, Ag challenge resulted in the death of more than two-thirds of the sensitized animals, whereas none of the nonsensitized control mice died as a result of Ag infusion. Sensitized normal (WBB6F1(-)+/+ or WCB6F1(-)+/+) mice and +/+BM-->W/Wv mice developed increases in heart rate that were significantly greater than those of nonsensitized +/+ mice or those of sensitized mast cell-deficient mice, indicating that mast cells contribute to the tachycardia observed in this form of active anaphylaxis. By contrast, even though some of the pulmonary changes associated with active anaphylaxis were more severe in +/+ than in mast cell-deficient mice, it was not clear to what extent this difference was mast cell dependent. W/Wv mice undergoing active anaphylaxis developed decreases in systemic arterial blood pressure that occurred more rapidly and were more severe than those observed in the congenic +/+ mice, indicating that the hypotension associated with this model of anaphylaxis also can occur by mast cell-independent mechanisms. We conclude that in this model of anaphylaxis mast cells: 1) are required for the development of the tachycardia response; 2) may contribute to, but are not essential for, production of decreases in lung function; and 3) are not necessary for the development of hypotension or death.

Age Factors↗
PubMed1993

Cloning and functional analysis of the mouse c-kit promoter.

The c-kit protooncogene encodes a tyrosine kinase receptor expressed during ontogeny and adult life by several important and developmentally distinct cell lineages. Mice carrying germ line c-kit mutations exhibit deficiencies in most of these lineages, demonstrating that c-kit function is necessary for their normal development. To facilitate the identification of cis-acting elements which regulate tissue-specific c-kit expression, we cloned and characterized a mouse c-kit promoter which is functional in different cell types. A major c-kit transcription initiation site (TIS), located 58 bp upstream from the translation initiation codon, is utilized in mouse mast cells and in c-kit-positive cells in the mouse cerebellum. The effects of deletions in the 5' flanking region on reporter gene activity identify three short regulatory regions which function in both mouse and human c-kit positive cell lines. The nucleotide sequence of this region does not include CCAAT or TATA boxes but contains consensus binding sites for Sp1, Ap-2 and several short GA-rich elements which resemble binding sites for the ETS-domain proteins.

Animals↗
PubMed1993

Regulation of mouse peritoneal mast cell secretory function by stem cell factor, IL-3 or IL-4.

We examined whether three cytokines that promote mouse mast cell development, the c-kit ligand stem cell factor (SCF), IL-3, or IL-4, also can directly stimulate or modulate mouse peritoneal mast cell (PMC) mediator release. Challenge of purified PMC with rat rSCF164 at 20 to 100 ng/ml for 30 min induced a modest release of serotonin (5-HT), whereas IL-3 or IL-4 did not directly stimulate 5-HT release. Experiments in which PMC were exposed to each cytokine for 15 min, and then to DNP-HSA Ag or anti-IgE antibody for a further 15 min, showed that SCF, but not IL-3 or IL-4, had an additive effect on the 5-HT release induced by either of the IgE cross-linking agents. In longer term experiments, SCF (0.16 to 500 ng/ml), IL-3 (2.5 to 100 ng/ml), or IL-4 (0.06 to 2.5 ng/ml) was added to peritoneal cell cultures for 48 h, during which the cells were passively sensitized with IgE anti-DNP antibody. Incubation of either unfractionated or highly purified PMC preparations with each of the three cytokines resulted in a concentration-related increase in 5-HT release upon subsequent challenge of the cells with DNP-HSA Ag. However, after pretreatment of peritoneal cells for 48 h with each cytokine, only IL-4 (10 ng/ml) enhanced release of 5-HT induced by calcium ionophore A23187 (0.25 microM); IL-3 (100 ng/ml) had no effect, whereas SCF (100 ng/ml) significantly inhibited ionophore-induced release. Although IL-3 or SCF up-regulate responsiveness to IgE-dependent stimuli, we detected no effect of these cytokines on the binding of [125I]IgE to PMC. This suggests that the enhancing effects of SCF or IL-3 on IgE-dependent 5-HT release did not simply reflect changes in the amount of IgE bound to the cells. In conclusion, we found that SCF, IL-3, or IL-4 each exerted a different spectrum of stimulatory, costimulatory, or regulatory effects on the secretory function of mouse PMC.

Animals↗
PubMed1993

Distinct patterns of early response gene expression and proliferation in mouse mast cells stimulated by stem cell factor, interleukin-3, or IgE and antigen.

Stem cell factor (SCF) is encoded at the Sl locus of the mouse and is the ligand for the c-kit receptor. Recombinant rat SCF164 (rrSCF164) induces proliferation and promotes maturation of mouse mast cells in vitro and in vivo and can also induce c-kit receptor-dependent mouse mast cell degranulation. We now report that in both quiescent and non-quiescent mouse bone marrow-derived cultured mast cells (BMCMC) rrSCF164 induces increased mRNA levels for the "early response genes" c-fos, c-jun and junB but has only slight effects on the expression of junD. Recombinant mouse interleukin-3 (IL-3) also promotes proliferation of both quiescent and non-quiescent BMCMC. However, IL-3 induces increased expression of c-fos and junB only in quiescent BMCMC. Cross-linking of Fc epsilon receptor type I (Fc epsilon RI) on BMCMC by IgE and specific antigen induces a pattern of early gene expression very similar to that induced by rrSCF164. However, BMCMC stimulated through the Fc epsilon RI did not proliferate and, in comparison to control BMCMC, exhibited significantly decreased proliferation in response to rrSCF164 or IL-3. These results indicate that stimulation of BMCMC proliferation by IL-3 or rrSCF164 induces distinct patterns of early response gene expression and suggest that the proliferative effects of these growth factors may be mediated through distinct signal transduction pathways. Our data also point to previously unappreciated similarities between the effects of signaling through the c-kit receptor or the Fc epsilon RI on mast cell expression of fos and jun genes.

Animals↗
PubMed1993

Activation of MAP kinases, pp90rsk and pp70-S6 kinases in mouse mast cells by signaling through the c-kit receptor tyrosine kinase or Fc epsilon RI: rapamycin inhibits activation of pp70-S6 kinase and proliferation in mouse mast cells.

The high-affinity receptor for IgE, Fc epsilon RI, represents the major cell surface structure through which mast cells express immunologically specific secretory function. By contrast, the stem cell factor receptor (SCFR), which is encoded by c-kit, is essential for normal mast cell development. The signaling pathways initiated by the stimulation of mast cells through the Fc epsilon RI, which lacks intrinsic kinase activity, and the SCFR, a member of the receptor tyrosine kinase family, generally have been regarded to be distinct. We report here that mouse mast cells stimulated either with SCF or with IgE and specific antigen exhibit a remarkably similar pattern of activation of mitogen-activated protein kinases (MAPK), 90 kDa-S6 kinases (pp90rsk), and pp70-S6 kinases (pp70-S6K). These results indicate that all three families of protein kinases are associated with the cell surface receptor-dependent activation of secretion, as well as proliferation, in mast cells. We also show that the immunosuppressant rapamycin, but not FK506, can inhibit both SCF-dependent pp70-S6 kinase activation and SCF-dependent proliferation in mouse mast cells, without suppressing IgE- and antigen-dependent mediator release. These findings suggest that the activation of pp70-S6 kinase represents an important link in the stimulation of cell proliferation by SCF. Our results also indicate that the intracellular signaling pathways initiated by stimulation of mast cells through the Fc epsilon RI or the SCFR exhibit more overlap than has previously been appreciated.

Animals↗
PubMed1993

Mast cell cytokines in allergy and inflammation.

Recent findings indicate that mast cells can influence biological responses through the production of cytokines and suggest that many allergic reactions and other biological processes may be regulated by a "mast cell-leukocyte cytokine cascade". This hypothesis proposes that certain biological responses are initiated by mast cell activation, resulting in the mast cell-dependent release of TNF-alpha and other cytokines which can promote the recruitment of eosinophils, neutrophils, and other effector cells. The recruited effectors then influence the progression of the response by providing additional sources of some cytokines which also can be elaborated by mast cells, as well as by producing other cytokines not known to be of mast cell origin.

Animals↗
PubMed1993

Ultrastructure of human dermal mast cells in 29 different lysosomal storage diseases.

The effect of lysosomal storage diseases on the ultrastructure of human mast cells has not previously been reported. Indeed, there has been little published evidence indicating that mast cells contain typical lysosomes. However, mast cell cytoplasmic granules contain hydrolases similar to those found in lysosomes, but which differ from lysosomal hydrolases in exhibiting optimal activity at higher pH. We therefore examined by transmission electron microscopy the dermal mast cells in 58 biopsies of patients exhibiting 1 of 29 different lysosomal storage diseases. We found mast cells containing abnormal lysosomes in 16 of these disorders. In 6 of these 16 diseases, the mast cells' cytoplasmic granules appeared normal. These observations indicate that human mast cells can contain lysosomes, and provide evidence that the enzymes affected by lysosomal storage diseases are active in mast cells.

Biopsy↗
PubMed1993

Reversible expansion of primate mast cell populations in vivo by stem cell factor.

Mast cell development in mice is critically regulated by stem cell factor (SCF), the term used here to designate a product of fibroblasts and other cell types that is a ligand for the tyrosine kinase receptor protein encoded by the proto-oncogene c-kit. However, the factors which regulate the size of mast cell populations in primates are poorly understood. Here we report that the subcutaneous administration of recombinant human SCF (rhSCF) to baboons (Papio cynocephalus) or cynomolgus monkeys (Macaca fascicularis) produced a striking expansion of mast cell populations in many anatomical sites, with numbers of mast cells in some organs of rhSCF-treated monkeys exceeding the corresponding values in control monkeys by more than 100-fold. Animals treated with rhSCF did not exhibit clinical evidence of mast cell activation, and discontinuation of treatment with rhSCF resulted in a rapid decline of mast cell numbers nearly to baseline levels. These findings are the first to demonstrate that a specific cytokine can regulate mast cell development in primates in vivo. They also provide the first evidence, in any mammalian species, to indicate that the cytokine-dependent expansion of tissue mast cell populations can be reversed when administration of the cytokine is discontinued.

Animals↗