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J Gauldie

Publications and source records attributed to J Gauldie.

At least 145 records · Page 8Linked to original sources
PubMed1992

Evidence that interleukin-6 does not play a role in the stimulation of platelet production after induction of acute thrombocytopenia.

The induction of thrombocytopenia results in elevated levels of thrombopoietin (TPO), which can be detected in the plasma of experimental animals. Acute, severe thrombocytopenia (platelet count less than 5% of control) was produced in mice by the administration of either guinea pig or rabbit antimouse platelet antiserum. Control mice received equal volumes of normal serum. At various times after the induction of thrombocytopenia (0.5, 1, 2, 3, 4, 6, 12, and 24 hours) citrated plasma was collected, and circulating interleukin-6 (IL-6) levels were measured using the IL-6-dependent murine hybridoma cell line B9. At no time points after induction of thrombocytopenia were plasma IL-6 levels significantly different from control animals that received normal serum. However, injection of heterologous serum did result in slightly elevated plasma IL-6 levels (at 2 and 3 hours) compared with basal levels measured in uninjected animals. This brief increase was not related to the production of thrombocytopenia. Protein fractions from the plasma of thrombocytopenic rabbits were also tested for the presence of IL-6. Preparations that contained TPO, as shown by stimulation of megakaryocyte maturation in vitro, did not contain detectable levels of IL-6. The ability of the B9 assay to detect the elevation of IL-6 levels in murine or rabbit plasma was verified after the administration of bacterial endotoxin, which is known to increase circulating IL-6 concentrations. IL-6 levels were highly elevated in rabbit or mouse serum after the administration of 5 mg/kg or 1 mg/kg of endotoxin, respectively. Anti-IL-6 antiserum did not neutralize the in vitro megakaryocyte maturation activity of partially purified TPO from the plasma of thrombocytopenic rabbits. In addition, IgG purified from the same antiserum did not neutralize partially purified TPO, as shown after incubation with TPO and subsequent precipitation with agarose-bound protein A. These results show that, unlike TPO, levels of IL-6 do not increase after the induction of acute, severe thrombocytopenia, and strongly suggest that IL-6 does not mediate the thrombopoietic response to acute thrombocytopenia. Although prolonged administration of IL-6 has been shown to induce thrombocytosis, IL-6 and TPO are apparently different and immunologically distinct molecules.

Animals↗
PubMed1992

Serum T-kininogen levels increase two to four months before death.

We have reported an accumulation of T-kininogen mRNA in the liver of aging Sprague-Dawley rats. T-kininogen is a cysteine proteinase inhibitor. Since a disruption of the intracellular protein degradation machinery is known to occur during senescence, we wished to further define the role of this protein in the aging process. As a first step, we have measured T-kininogen levels both in serum and within the liver. We have found that serum protein levels are indeed augmented during senescence, although not as dramatically as the mRNA (2.5-fold versus 8.3-fold). Immunocytochemistry, as well as Western blot analysis suggests that this is due to the presence of T-kininogen within hepatic cells in aged rats. Life-long dietary restriction, a known age-prolonging treatment, decreases the overexpression of the protein in 24-month-old rats. Later, diet-restricted animals still show an increased expression from the gene, the effect being delayed but not abolished by dietary manipulation. Interestingly, a longitudinal study indicated the existence of a positive correlation between the time of increase of serum T-kininogen and the time of death of the animal. Serum T-kininogen was found to increase 2.5-4 months before death.

Aging↗
PubMed1992

Recombinant oncostatin M stimulates the production of acute phase proteins in HepG2 cells and rat primary hepatocytes in vitro.

Acute inflammation is characterized by increased liver output of acute phase proteins (APP). Several cytokines including IL-6, leukemia inhibitory factor, and IL-11 are capable of stimulating APP synthesis by hepatocytes and hepatoma cells. We have tested the activity of a separate and unique cytokine oncostatin M (OM) and have found potent APP-inducing activity of human recombinant OM on hepatocytes. OM acted in a dose-dependent fashion (ED50 5 to 10 ng/ml) in stimulating APP synthesis in human HepG2 cells, rat H35 cells, and primary rat hepatocyte cultures, but not human Hep3B cells. Human OM induced equivalent to or greater responses than IL-6 in HepG2 cells, however, it was less effective than human IL-6 in stimulating rat cells. Northern analysis showed that OM stimulated mRNA levels of haptoglobin and alpha 1-antichymotrypsin in HepG2 cells. OM induced CAT activity in HepG2 cells transfected with CAT constructs containing IL-6-responsive elements, suggesting that OM induces transcription of native proteins through mechanisms involving IL-6-responsive element-like sequences in gene promoters. OM was also shown to act additively with IL-6 or leukemia inhibitory factor and synergistically with glucocorticoid or IL-1 in the induction of specific APP. These results suggest that OM plays a role as a mediator of APP synthesis in inflammatory responses.

Acute-Phase Proteins↗
PubMed1992

IL-1 beta and IL-6 gene expression in alveolar macrophages: modulation by extracellular matrices.

Interleukin-1 (IL-1) and interleukin-6 (IL-6) are two cytokines involved in a variety of host inflammatory reactions. The alveolar macrophage (AM), a predominant cell source for IL-1 and IL-6, exists in a microenvironment in which there are abundant extracellular matrix (ECM) components, and it is likely that ECM may participate in the inflammatory response in the lung by modulating the effector activities of AMs. To investigate this hypothesis, we cultured rat AMs on different substrates including plastic, collagen, and airways fibroblast-derived ECM (fECM) and assessed IL-1 beta and IL-6 gene expression in these cells. Our study demonstrates that cytokine gene expression in AMs is affected by the conditions of culture. IL-1 gene expression is stimulated by adherence to plastic and exposure to endotoxin, whereas IL-6 mRNA is detectable only in the cells stimulated by endotoxin. Coating the plastic with collagen or fECM modifies cytokine gene expression. At early time points, collagen enhances gene expression. At later times (5 days), actin and cytokine gene expression are predominantly maintained in the endotoxin-stimulated cells cultured on fECM. These findings suggest an extracellular environment-directed mechanism of regulation of cytokine expression in alveolar macrophages.

Actins↗
PubMed1992

Human upper airway structural cell-derived cytokines support human peripheral blood monocyte survival: a potential mechanism for monocyte/macrophage accumulation in the tissue.

A central feature of chronic airway inflammation is accumulation of monocyte/macrophages in the tissue. It is well known that circulating monocytes are short-lived cells whereas tissue macrophages are longer-lived cells. One mechanism that may account for accumulation of inflammatory cells includes enhanced survival and/or differentiation of these cells. Recent studies imply that signals released by tissue structural cells may be crucial in these events. To investigate this notion, human blood monocytes were cultured with either culture medium alone as a control, human nasal epithelial cell-conditioned medium (EpCM), or fibroblast-conditioned medium (FCM) for more than 1 wk. Survival of monocytes in medium alone was 17% at day 7, whereas survival of those cultured with 50% of EpCM or FCM was 62% and 64%, respectively. The effect of EpCM and FCM was dose dependent. Preincubation of either conditioned medium (CM) with an antibody against granulocyte/macrophage colony-stimulating factor (GM-CSF) or an antibody against macrophage colony-stimulating factor (M-CSF) resulted in a partial abrogation of the survival-enhancing effect, to an average of 50% and 30%, respectively. Complete inhibition was obtained by preincubation of the CM with a combination of both antibodies. The effect of CM represented true survival because CM only induced a low profile of [3H]thymidine incorporation and, furthermore, less than 0.3% of the cells cultured with CM underwent DNA synthesis as assessed by autoradiography. In addition, ultrastructural observations demonstrated that most monocytes cultured with either CM but not with control culture medium assumed ultrastructural features of macrophages by day 8 of culture.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Differentiation↗
PubMed1992

Bronchial epithelial cell-derived cytokines (G-CSF and GM-CSF) promote the survival of peripheral blood neutrophils in vitro.

Neutrophil accumulation in the respiratory tract occurs in a variety of inflammatory disorders, particularly those associated with cigarette smoking. We examined whether bronchial epithelial cells could contribute to this accumulation through the production of factors that increased the survival of neutrophils. Pure primary cultures of human bronchial epithelial cells (HBEC) were used to generate conditioned medium (CM), and the effect of this CM on the survival of neutrophils in vitro was examined. When neutrophils were cultured in control medium, survival was 8.7 +/- 1.7% at 72 h. In contrast, culture of neutrophils in CM resulted in a dose-dependent increase in survival: 22.6 +/- 5.5, 43.6 +/- 4.2, and 64 +/- 3.8% in 1, 10, and 50% CM respectively (mean +/- SEM; P < 0.05). As evidenced by the examination of neutrophil DNA, this prolongation of survival was associated with suppression of apoptosis. Cytokines with known actions on neutrophil biology identified in the CM included granulocyte colony-stimulating factor (G-CSF), granulocyte/macrophage colony-stimulating factor (GM-CSF), and interleukin-8. Through the use of specific neutralizing antibodies, G-CSF and GM-CSF were identified as promoting neutrophil survival. Neutrophil survival was prolonged in the presence of either recombinant human (rh) G-CSF or rhGM-CSF alone in a dose-dependent fashion. In contrast to the response of eosinophils to HBEC-CM, steroid treatment did not prevent the increase in neutrophil survival induced by HBEC-CM. In summary, we show that bronchial epithelial cells markedly increase the survival of human neutrophils in vitro via the release of G-CSF and GM-CSF.(ABSTRACT TRUNCATED AT 250 WORDS)

Apoptosis↗
PubMed1992

Eosinophils in chronically inflamed human upper airway tissues express transforming growth factor beta 1 gene (TGF beta 1).

Transforming growth factor beta (TGF beta) is a multifunctional protein which has been suggested to play a central role in the pathogenesis of chronic inflammation and fibrosis. Nasal polyposis is a condition affecting the upper airways characterized by the presence of chronic inflammation and varying degrees of fibrosis. To examine the potential role of TGF beta in the pathogenesis of this condition, we investigated gene expression and cytokine production in nasal polyp tissues as well as in the normal nasal mucosa. By Northern blot analysis using a porcine TGF beta 1 cDNA probe, we detected TGF beta 1-specific mRNA in nasal polyp tissues, as well as in the tissue from a patient with allergic rhinitis, but not in the normal nasal mucosa. By the combination of tissue section staining with chromotrope 2R with in situ hybridization using the same TGF beta 1 probe, we found that approximately 50% of the eosinophils infiltrating the polyp tissue express the TGF beta 1 gene. In addition, immunohistochemical localization of TGF beta 1 was detected associated with extracellular matrix as well as in cells in the stroma. These results suggest that in nasal polyposis where eosinophils are the most prevalent inflammatory cell, TGF beta 1 synthesized by these cells may contribute to the structural abnormalities such as stromal fibrosis and basement membrane thickening which characterize this disease.

Chronic Disease↗
PubMed1992

Alpha 2-macroglobulin expression in the mesometrial decidua and its regulation by decidual luteotropin and prolactin.

During decidualization, cells of the endometrium grow and differentiate giving rise to two different decidual tissues located in either the antimesometrial or mesometrial site of the uterus in the rat. These tissues have different functions in pregnancy. The antimesometrial decidua is an endocrine gland that secretes hormones, whereas the mesometrial decidua appears to play an important role in limiting trophoblast invasion. Since the decidual tissue of the rat produces alpha 2-macroglobulin (alpha 2MG), we examined whether this potent protease inhibitor is specifically expressed by the mesometrial tissue, the site of trophoblast invasion, and whether the alph 2MG gene is regulated by decidual luteotropin (DLt), the PRL-like hormone secreted by the neighboring antimesometrial cells. To determine the secretory proteins of the rat decidua, antimesometrial and mesometrial tissues were dissected out from pseudopregnant rats and cultured with [35S]methionine. The major protein secreted by the antimesometrial cell was the 29-kilodalton decidual luteotropin, whereas a 180-kilodalton protein was predominantly secreted by the mesometrial tissue. Immunoprecipitation studies of 35S-radiolabeled proteins revealed that this high mol wt protein is alpha 2MG and that it is secreted exclusively by the cells forming the mesometrial tissue. To examine whether the alpha 2MG gene was also expressed specifically in the mesometrial decidua, total RNA was isolated from both mesometrial and antimesometrial tissues of day 9-12 pseudopregnant rats and hybridized with alpha 2MG cDNA. Northern blot analysis revealed a 5.4-kilobase message, which was abundantly expressed in the mesometrial decidua. Little, if any, alpha 2MG mRNA was detected in antimesometrial decidua. The ontogeny of the message in the decidua correlated well with the development of the mesometrial tissue. To examine whether alpha 2MG expression is regulated by DLt and/or PRL, a highly specific polyclonal antibody to DLt was generated and decidual tissues were cultured in the presence or absence of DLt antibodies with or without PRL. Neutralization of DLt caused a marked decrease in alpha 2MG mRNA levels. This down-regulation was totally reversed by the addition of PRL and was not affected by alpha 2MG antibodies. In summary, the results of this investigation revealed a compartmentalized gene expression, synthesis and secretion of alpha 2MG in the decidua. The secretion of this protease inhibitor, specifically by the mesometrial tissue which is the site of trophoblast invasion, may be the reason for the minimal amount of tissue damage that occurs during placentation.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

The expression of interleukin-6 by a rat macrophage-derived cell line.

A stable rat macrophage-derived cell line (RMSV1) was established by transformation of primary peritoneal exudate cells with the SV40 virus. The RMSV1 cell line was used as a model to study the regulation of the interleukin-6 (IL6) gene expression in rat macrophages with respect to lipopolysaccharides (LPS), interleukin-1 (IL1) and glucocorticoids. The IL6 mRNA level in RMSV1 cell lines was induced 20-fold within 4 h by LPS, whereas IL1 had no effect. The glucocorticoids were able to inhibit completely the induction of the IL6 mRNA synthesis by LPS, indicating the negative regulation of the IL6 gene expression by glucocorticoids.

Animals↗
PubMed1991

Counteracting effects of dexamethasone and alpha 2-macroglobulin on inhibition of proliferation of normal and neoplastic rat hepatocytes by transforming growth factors-beta type 1 and type 2.

Primary cultures of hepatocytes isolated from normal F-344 rats or from F-344 rats with hepatocellular carcinomas generated by a 2-step model of chemical carcinogenesis were used to determine if dexamethasone (DEX) or alpha 2-macroglobulin (alpha 2M) modify the ability of transforming growth factors-beta type I (TGF-beta I) and type 2 (TGF-beta 2) to inhibit labelling index of hepatocytes cultured continuously with or without epidermal growth factor (EGF). Both TGF-beta 1 and beta 2 were equivalently potent inhibitors of S-phase DNA synthesis in normal and neoplastic hepatocytes as determined by 3H-thymidine autoradiography. Both DEX (1 to 100 microM) and alpha 2M (50-200 microM) partially counteracted the mito-inhibitory effect of both TGF-betas on the proliferation of normal and surrounding hepatocytes. In contrast, neoplastic hepatocytes cultured with DEX released much less immunoreactive alpha 2M and were less able to overcome the inhibitory effect of TGF-beta than normal or surrounding hepatocytes. Purified bovine alpha 2M partially counteracted the inhibition of TGF-beta 1 or beta 2 of both surrounding and neoplastic hepatocytes. Both DEX and alpha 2M were more effective against the mito-inhibitory activity of TGF-beta 2. Our data suggest that alpha 2M released by DEX-treated normal hepatocytes contributes to the counteraction of the TGF-beta effect by DEX. Our results support the hypothesis that glucocorticoids and growth-factor-binding proteins may have important roles in modulating the effects of TGF-beta on normal hepatocyte proliferation and suggest that under some conditions hepatocellular neoplasms can be more sensitive than normal hepatocytes to inhibition of proliferation by TGF-beta.

Animals↗
PubMed1991

The acute phase protein response during parasitic infection.

There is a paucity of comprehensive studies of the APP response in parasitic infection. This should be remedied for two reasons. First, as there is a limited number of cytokines with hepatocyte-stimulating activities, and as each one elicits a unique spectrum of protein changes, examination of the APP response during infection could provide insight into the cytokines involved. Second, the presence of IL-1, IL-6 and TNF, the mediators of the APR, in tissues and circulation have important implications for subsequent immune responses.

Acute-Phase Proteins↗
PubMed1991

Interleukin-6 is a centrally acting endogenous pyrogen in the rat.

Intracerebroventricular (i.c.v.) injection of human recombinant interleukin-6 (IL-6; 20-100 ng) caused significant increases in colonic temperature and resting oxygen consumption (VO2) in conscious rats. These effects were prevented by pretreatment with a cyclooxygenase inhibitor (flurbiprofen, 1 mg/kg, i.p.) or a corticotrophin-releasing factor antagonist (alpha-helical CRF9-41, 25 micrograms, i.c.v.). Higher doses of IL-6 (i.c.v.) caused only small changes in VO2 and temperature, and very high doses given intravenously (i.v.) (4 micrograms/kg) were required to stimulate these parameters. Central injection of anti-rat IL-6 antibody inhibited the effects of interleukin-1 beta (i.c.v.) or endotoxin injection (i.p.) on colonic temperature and VO2 in conscious rats. These data indicate that IL-6 is an important endogenous pyrogen that acts within the central nervous system.

Animals↗
PubMed1991

Structural cell-derived cytokines in allergic inflammation.

Based on observations of fluctuations in progenitors for inflammatory cells during allergic responses, we have proposed that a primary determinant of allergic inflammation involves microenvironmental influences on hemopoietic cell differentiation and phenotype; in addition, as a corollary of this, inflammatory cell burden is proposed as an important indicator of the severity and pattern of the inflammatory process in allergy. The studies outlined here focus on the effects of epithelial-cell- and fibroblast-derived cytokines on granulocytic and monocytic cell differentiation and activation in models involving allergic reactions in the upper and lower airways. Pure cultures of nasal or bronchial epithelial cells or fibroblasts are observed to give rise to cytokines important in inducing the differentiation of basophils, eosinophils, neutrophils and monocyte/macrophages. Gene expression, production and secretion of granulocyte/macrophage-colony-stimulating factor, interleukin-6 (IL-6) and IL-8 can be demonstrated in vitro and in vivo. Up-regulation of gene expression and production of these cytokines, which are important in inducing basophil, eosinophil and neutrophil/macrophage differentiation in several assays, is seen with IL-1 and the neuropeptide substance P; conversely, inhibition of cytokine production by structural cells is observed after pretreatment with corticosteroids in vitro, paralleling in vivo effects. Other modulatory effects also examined include: antiallergic compounds, which may affect posttranscriptional events in cytokine production, and heavy metal ions, which can also induce changes in gene expression. Structural-cell-derived extracellular matrices appear also to be important both in mast cell differentiation and in macrophage cytokine gene expression, both of which potentially feedback upon chronic allergic inflammatory processes, leading to their perpetuation.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchi↗
PubMed1991

Human upper airway epithelial cell-derived granulocyte-macrophage colony-stimulating factor induces histamine-containing cell differentiation of human progenitor cells.

Nasal polyps and allergic rhinitis are upper airway inflammatory conditions characterized by increased numbers of eosinophils and metachromatic cells in the epithelial layer of the nasal mucosa. The objective of the current studies was to investigate the potential contribution of epithelial cells to the accumulation of inflammatory cells in the tissue. We have established pure cultures of human upper airway epithelial cells from normal and inflamed nasal polyps and allergic rhinitis tissue and examined the ability of conditioned medium from these cells (EpCM) to induce differentiation of human hemopoietic progenitors in vitro. We show that, under appropriate culture conditions, EpCMs, particularly those from cells derived from inflamed tissues, induce histamine-containing cell differentiation of cells of the human HL-60 myeloid leukemia cell line. These EpCMs also induce the emergence of both eosinophil/basophil and granulocyte/macrophage colonies in methylcellulose cultures of human peripheral blood mononuclear cells. We also show that CMs from epithelial cells derived from inflamed tissues contain greater amounts of granulocyte-macrophage colony-stimulating factor (GM-CSF) compared to CMs from normal epithelial cells. Finally, we show that the histamine-containing cell differentiation of HL-60 cells as well as the colony growth induced by EpCM can be fully inhibited by preincubating this CM with a monoclonal neutralizing antibody to human GM-CSF. These studies: (a) illustrate the ability of human upper airway epithelial cells to secrete GM-CSF in vitro; (b) demonstrate differences between normal and inflamed tissue-derived epithelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1991

Neutrophilic differentiation induced by human upper airway fibroblast-derived granulocyte/macrophage colony-stimulating factor (GM-CSF).

We have established primary lines of fibroblasts from nasal polyp (NP) tissues as well as from normal nasal (NN) mucosa and have examined the ability of these cells to release hormone-like peptide messenger molecules (cytokines). Our results show that human upper airway fibroblasts release granulocyte/macrophage colony-stimulating factor (GM-CSF), granulocyte-CSF (G-CSF), and macrophage-CSF (M-CSF) in vitro. We also show that fibroblasts derived from NP tissue express the gene for GM-CSF at a higher level, and release the GM-CSF product in greater amounts, than NN fibroblasts. In addition, we have examined the ability of these fibroblasts and their conditioned medium (CM) to induce differentiation of human hemopoietic progenitor cells. After 7 d, cultures of these cells in RPMI-10% fetal bovine serum contained 5 +/- 2.5% (mean +/- SD) neutrophils. In contrast, culture of progenitor cells with fibroblasts resulted in significantly greater neutrophilic differentiation (18 +/- 4%). Culture in fibroblast-CM induced a similar degree of differentiation, and fibroblast-CM from NP fibroblasts elicited greater differentiation compared to CM from NN fibroblasts (17.5 +/- 3 versus 12 +/- 3%). The neutrophilic differentiation induced by fibroblast-CM can be fully inhibited by preincubating this CM with a monoclonal neutralizing antibody to human GM-CSF. Thus, our results demonstrate: (1) the ability of human upper airway fibroblasts to release GM-, G-, and M-CSF in vitro; (2) that fibroblasts derived from NP tissues express the gene and release the product GM-CSF at greater levels compared to NN fibroblasts; and (3) that fibroblast-derived GM-CSF causes neutrophilic differentiation of human hemopoietic progenitors.

Animals↗