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Biomedical subjects

T J Standiford

Publications and source records attributed to T J Standiford.

At least 19 recordsLinked to original sources
PubMed1992

IL-7 up-regulates the expression of IL-8 from resting and stimulated human blood monocytes.

Blood monocytes are important cellular sources of a vast array of bioactive substances, including regulatory and chemotactic cytokines. The regulation of these cytokines is of critical importance to the expression of acute and chronic inflammatory responses. IL-7, a T and B cell-activating cytokine, has recently been shown to have stimulatory effects on the expression of several monocyte-derived proinflammatory cytokines. We now describe the induction of IL-8 mRNA and extracellular protein from human blood monocytes by IL-7. The up-regulation of IL-8 mRNA by IL-7 was not altered by concomitant treatment with cycloheximide, suggesting that the direct stimulatory effects of IL-7 were not dependent upon de novo protein synthesis. In addition, IL-7 significantly potentiated the production of IL-8 from LPS-, TNF-, and IL-1-treated peripheral blood monocytes. Our findings suggest that IL-7 may play a critical role in the modulation of macrophage-derived cytokine expression and may function in vivo as an important proinflammatory cytokine.

Base Sequence↗
PubMed1992

Expression and regulation of human pulmonary fibroblast-derived monocyte chemotactic peptide-1.

Monocyte recruitment is essential for maintenance of normal pulmonary macrophage populations. In addition, acute and chronic inflammatory pulmonary diseases are associated with sequestration of mononuclear phagocytes in the lung. Although alveolar macrophages (AM phi) can secrete a number of potent inflammatory and chemoattractment mediators, these immune cells do not produce monocyte chemotactic peptide (MCP-1) in response to lipopolysaccharide (LPS), tumor necrosis factor (TNF), or interleukin-1 beta (IL-1 beta). The pulmonary fibroblast (PF) may play a pivotal role in monocyte recruitment. In these studies, we demonstrate a time- and dose-dependent production of PF-derived steady-state MCP-1 mRNA, MCP-1 antigen, and monocyte chemotactic bioactivity attributable to MCP-1. In cellular models examining cytokine networks between AM phi and PF, LSP-stimulated AM phi (conditioned media) induced PF-derived steady-state MCP-1 mRNA expression that was markedly attenuated by the presence of neutralizing TNF and IL-1 beta antibodies. Furthermore, we showed the dose- and time-dependent suppression of IL-1 beta-stimulated PF-derived MCP-1 by dexamethasone and prostaglandin E2. These findings demonstrated that PF are an important cellular source of MCP-1 and this production of MCP-1 may be influenced by immunomodulators.

Antibodies↗
PubMed1992

Interleukin-4 differentially regulates tumor necrosis factor-alpha gene expression by human T lymphocytes and monocytes.

Tumor necrosis factor-alpha (TNF-alpha), a product of both mononuclear phagocytes and T lymphocytes, is an important proximal mediator of a number of acute and chronic inflammatory disease states. In this investigation we examine the regulatory effects of the lymphocyte product interleukin-4 (IL-4) on the gene expression of TNF-alpha from stimulated human peripheral blood monocytes (PBM) and T lymphocytes. We demonstrated the dose-dependent suppression of TNF-alpha mRNA and protein synthesis from lipopolysaccharide-treated PBM by IL-4. The suppressive effects of IL-4 appear to be dependent upon de novo protein synthesis, as cycloheximide abrogated the IL-4-induced reduction in TNF-alpha mRNA levels from PBM. In contrast to the suppressive effects of IL-4 on PBM-derived cytokine expression, IL-4 did not alter TNF-alpha mRNA expression from alpha-Cd3 or PMA + alpha-CD-28-treated T lymphocytes. Moreover, IL-2 mRNA expression from similarly treated T lymphocytes was unaltered by IL-4. Our findings demonstrate that disparity exists in the regulation of TNF-alpha gene expression from different immune cell populations which may have important implications in the evolution of acute and chronic inflammatory responses.

Base Sequence↗
PubMed1992

Neutrophilic alveolitis in idiopathic pulmonary fibrosis. The role of interleukin-8.

Idiopathic pulmonary fibrosis is an immunologically mediated pulmonary disorder in which activated alveolar macrophages (AM) and neutrophils play cardinal roles in the pathogenesis of the inflammatory lung lesion. The factors responsible for the induction and perpetuation of the neutrophilic alveolitis are not known. Recently, a novel cytokine (Interleukin-8) was described that is released by activated mononuclear phagocytes and a variety of other cell types, and it exhibits potent chemotactic activity for polymorphonuclear leukocytes (PMN). Increased expression of IL-8 has been described in other inflammatory disorders characterized by neutrophilic infiltration, including psoriasis, rheumatoid arthritis, and the sepsis syndrome, but no studies have assessed this cytokine in the context of interstitial pulmonary disorders. We have previously shown that normal human AM release IL-8 upon appropriate stimulation, but data assessing the expression of IL-8 by human AM in specific pulmonary disease states are lacking. In this study, we examined the expression of steady-state mRNA for IL-8 by human alveolar macrophages obtained by bronchoalveolar lavage (BAL) from patients with idiopathic pulmonary fibrosis (IPF) or sarcoidosis and from healthy volunteers. Because it is known that adherence to plastic culture plates may up-regulate gene expression for IL-8 in the absence of additional stimulation, we extracted mRNA immediately from the cell pellet obtained by BAL rather than using cultured alveolar macrophage monolayers. Northern blot analysis was performed to determine IL-8 mRNA expression. We found that BAL cells from patients with IPF constitutively expressed mRNA for IL-8, and the amount of IL-8 mRNA (as assessed by laser densitometry) correlated with the percent of neutrophils on BAL.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Regulation of human alveolar macrophage- and blood monocyte-derived interleukin-8 by prostaglandin E2 and dexamethasone.

Mononuclear phagocytes are important immune effector cells that play a fundamental role in cellular immunity. In addition to their antigen-presenting and phagocytic activities, monocytes/macrophages produce a vast array of regulatory and chemotactic cytokines. Interleukin-8 (IL-8), a potent neutrophil-activating and chemotactic peptide, is produced in large quantities by mononuclear phagocytes and may be an important mediator of local and systemic inflammatory events. In this investigation, we describe the effects of prostaglandin E2 (PGE2) and dexamethasone (Dex) on IL-8 mRNA and protein expression from lipopolysaccharide (LPS)-treated human peripheral blood monocytes (PBM) and alveolar macrophages (AM). We demonstrate the dose-dependent suppression of IL-8 from LPS-stimulated PBM by PGE2. Treatment of stimulated PBM with 10(-6) M PGE2 resulted in maximal inhibition, causing 60% suppression of both IL-8 mRNA and extracellular protein levels. In contrast, PGE2 (10(-6) to 10(-8) M) did not significantly alter IL-8 mRNA or protein expression from LPS-treated AM. Treatment of LPS-stimulated PBM and AM with Dex (10(-6) to 10(-8) M) resulted in 75% decline in IL-8 mRNA and extracellular protein from either cell population. Pretreatment of PBM with PGE2 or Dex 1 or 2 h before LPS stimulation caused a significant suppression of steady-state IL-8 mRNA levels; however, administration of either of these modulators 1 or 2 h after LPS stimulation failed to have an inhibitory effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1992

Expression and regulation of human alveolar macrophage-derived interleukin-1 receptor antagonist.

The alveolar macrophage (AM) is the sentinel immune cell of the distal airspace of the lung. These mononuclear phagocytic cells represent the major host defense against inhaled environmental agents. When activated, the AM has the capacity to release reactive oxygen and arachidonic acid metabolites and produce a number of cytokines, such as interleukin-1 (IL-1). This latter cytokine has pleiotropic effects on a variety of cells and has been implicated as one of the preeminent mediators of acute inflammation. Recently, an IL-1 receptor antagonist (IRAP) has been isolated, purified, and cloned from peripheral blood monocytes (PBM) stimulated with either adherent IgG (adhIgG) lipopolysaccharide (LPS), or phorbol myristate acetate. IRAP acts as a true receptor antagonist without agonist activity. We postulated that the AM would be a significant cellular source of IRAP from the lung. To test this hypothesis, normal human AM were immediately isolated or stimulated in a dose-dependent fashion with either LPS or adhIgG. For comparison, PBM were also isolated and treated in a similar manner. PBM expressed steady-state IRAP mRNA by Northern blot analysis only in response to LPS or adhIgG. In contrast, AM were found to express significant levels of antigenic IRAP by Western blot analysis, immunostaining, and specific ELISA, and express steady-state levels of IRAP mRNA under unstimulated culture conditions. Moreover, LPS or adhIgG failed to induce AM-derived IRAP antigen generation over unstimulated control.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchoalveolar Lavage Fluid↗
PubMed1992

Suppression of human alveolar macrophage-derived cytokines by amiloride.

Various human alveolar macrophage (AM)-derived cytokines in the lungs have been shown to be present under conditions of normal homeostasis as well as during the pathogenesis of inflammation. Although extensive investigation has demonstrated the induction of cytokines from AM, relatively little is known regarding endogenous and exogenous regulation of their production. Several pharmacologic agents, including corticosteroids, cyclooxygenase inhibitors, prostaglandins, and methyl-xanthines have been examined for their role in the modulation of mononuclear phagocyte-derived cytokines. In this study, we examine the role of amiloride for the regulation of AM-derived interleukin (IL)-8, tumor necrosis factor (TNF), IL-6, and IL-1 beta. Amiloride in concentrations of 10(-4) to 10(-6) M, concentrations capable of being achieved in the distal airways via nebulization, were shown to inhibit lipopolysaccharide-stimulated, AM-derived IL-8 and TNF in both a time- and dose-dependent fashion. In addition, 5-(N,N-hexamethylene) amiloride hydrochloride, an amiloride analogue with specific sodium channel antiport inhibition, resulted in a similar dose-dependent suppression of lipopolysaccharide-stimulated, AM-derived IL-8 production. Furthermore, the suppressive effect of amiloride appeared to be at the level of mRNA for IL-8, TNF, IL-1 beta, and IL-6, whereas steady-state levels of beta-actin mRNA remained unaltered. These findings would suggest that amiloride has a potentially important modulating influence for the regulation of AM-derived cytokines.

Amiloride↗
PubMed1992

Anoxia-hyperoxia induces monocyte-derived interleukin-8.

Ischemia-reperfusion and hyperoxia-induced pulmonary injury are associated with the presence of activated neutrophils (PMN) and cellular injury. Although the signals orchestrating the directed migration of these PMN during the pathogenesis of these disease states remain to be fully elucidated, it appears they may be dependent upon the production of certain neutrophil activating/chemotactic factors such as C5a, leukotriene B4, platelet-activating factor, and IL-8. The production of the latter chemotaxin by mononuclear phagocytes is especially intriguing as these cells can mediate inflammatory cell migration by either directly generating IL-8, or by inducing its production from surrounding nonimmune cells. In light of these observations, we propose that ischemia-reperfusion and oxidant stress, in vivo, may be simulated by anoxia-hyperoxia induced stress in vitro, and that this stress may act as a stimulus for the production of IL-8. We now show that isolated human blood monocytes respond to such an oxygen stress with augmented production of IL-8. In initial studies, monocytes demonstrated an increase in the production of IL-8 under anoxic preconditioning. Subsequently, monocytes were cultured under one of the following conditions for 24 h: (a) room air/5% CO2; (b) 95% N2/5% CO2 for 6 h, followed by room air/5% CO2 for 18 h; (c) 95% N2/5% CO2 for 6 h, followed by 95% O2/5% CO2 for 18 h; (d) room air/5% CO2 for 6 h, followed by 95% O2/5% CO2 for 18 h; or (e) 95% O2/5% CO2. Supernatants were isolated and analyzed for IL-8 antigen by specific IL-8 ELISA, demonstrating the production of monocyte-derived IL-8: 5.9 +/- 0.9, 11.4 +/- 1.7, 21.1 +/- 2.3, 14.6 +/- 2.4, and 26.3 +/- 4.7, ng/ml by designated conditions a, b, c, d, and e listed above, respectively. This variance in IL-8 production reflects altered rates of transcription as shown by Northern blot analysis and nuclear run-off assay. Furthermore, when monocytes were concomitantly treated with LPS (100 ng/ml) under in vitro hyperoxic conditions, both IL-8 steady-state mRNA and antigenic activity were two- to threefold greater than under room air conditions. The association of anoxic preconditioning and oxygen stress with augmented production of monocyte-derived IL-8 support the potential role for ischemia-reperfusion and hyperoxia-induced IL-8 production in vivo, providing a possible mechanism for PMN migration/activation in disease states characterized by altered tissue oxygenation.

Animals↗
PubMed1992

Cytokine-induced neutrophil-derived interleukin-8.

During acute inflammation, the first line of cellular response for host defense is the neutrophil. In addition to the historic role of the neutrophil as a phagocyte, recent studies have identified this cell as an important source of a number of cytokines. In this study, we provide evidence that the neutrophil is a significant source of interleukin-8 (IL-8). Neutrophils freshly isolated from whole blood were not found to constitutively express IL-8 mRNA. In contrast, when these leukocytes were cultured on plastic they were activated, leading to the significant expression of de novo steady-state levels of IL-8 mRNA. In addition, when neutrophils were treated with cycloheximide, there was evidence for "superinduction" of steady-state levels of IL-8 mRNA and inhibition of antigenic IL-8 production. Neutrophils were subsequently stimulated with lipopolysaccharide (LPS), tumor necrosis factor-alpha, or interleukin-1-beta and were found to express IL-8 mRNA and antigen in both a time- and dose-dependent manner. Furthermore, neutrophils stimulated with traditional chemotactic/activating factors, such as the split product of the fifth component of complement (C5a), formylmethionyleucylphenylalanine (fMLP), and leukotriene B4 (LTB4) in a dose-dependent manner did not produce significant antigenic IL-8, as compared with unstimulated controls. In contrast, when neutrophils were exposed to either of these neutrophil agonists in the presence of LPS, the production of antigenic IL-8 was significantly elevated, as compared with either of the stimuli alone, suggesting a synergistic response. These data would suggest that the neutrophil can no longer be viewed as only a phagocyte or warehouse for proteolytic enzymes, but is a pivotal effector cell that is able to respond to mediators in its environment and generate cytokines. This latter neutrophil response may be important for either the elicitation of additional neutrophils or to orchestrate the conventional immune response at sites of inflammation.

Antigens↗
PubMed1991

Alveolar macrophage-derived cytokines induce monocyte chemoattractant protein-1 expression from human pulmonary type II-like epithelial cells.

Many acute and chronic lung diseases are characterized by the presence of increased numbers of activated macrophages. These macrophages are derived predominantly from newly recruited peripheral blood monocytes and may play a role in the amplification and perpetuation of an initial lung insult. The process of inflammatory cell recruitment is poorly understood, although the expression of inflammatory cell-specific chemoattractants and subsequent generation of chemotactic gradients is likely involved. Although immune cells such as macrophages and lymphocytes are known to generate several inflammatory cell chemoattractants, parenchymal cells can also synthesize and secrete a number of bioactive factors. We now demonstrate the generation of significant monocyte chemotactic activity from tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 beta-treated pulmonary type II-like epithelial cells (A549). The predominant inducible monocyte chemotaxin had an estimated molecular mass of approximately 14-15 kDa and was neutralized by specific antibody to human monocyte chemotactic protein-1 (MCP-1). Induction of activity was accompanied by increases in steady-state mRNA level for MCP-1. These data are consistent with the induction of MCP-1 expression from A549 cells by TNF and IL-1. MCP-1 production from A549 cells could be induced by lipopolysaccharide (LPS)-stimulated alveolar macrophage (AM)-conditioned media, but not by LPS alone. The inducing activity in AM-conditioned media was neutralized with specific antibodies to IL-1 beta, but not TNF-alpha. Our findings suggest that the alveolar epithelium can participate in inflammatory cell recruitment via the production of MCP-1 and that cytokine networking between contiguous alveolar macrophages and the pulmonary epithelium may be essential for parenchymal cell MCP-1 expression.

Blotting, Northern↗
PubMed1991

Mononuclear cell adherence induces neutrophil chemotactic factor/interleukin-8 gene expression.

The accumulation of polymorphonuclear cells (PMN) in tissue is an essential element of the inflammatory response that is important in host defense. Adherence to endothelium constitutes the first step in PMN migration from the vascular compartment to the interstitium. We demonstrate that human peripheral blood mononuclear cells (PBMC) adherent to plastic can result in expression of interleukin-8 (IL-8), a potent PMN chemoattractant and activating cytokine. Northern blot analyses showed PBMC adherent to plastic expressed IL-8 steady-state mRNA levels by 30 min, peaked at 8 h, and then decreased over the next 16 h. In contrast, nonadherent PBMC (cultured in teflon chambers) expressed less than 25% of the maximal IL-8 steady-state mRNA levels as compared with adherent PBMC. Adherent PBMC-associated IL-8 determined by immunochemistry, supernatant chemotactic bioactivity, and extracellular antigenic IL-8 paralleled IL-8 mRNA expression. Antigenic and bioactive IL-8 were significantly apparent by 4-8 h, respectively, and increased significantly to maximal levels by 24 h. Furthermore, adherent PBMC IL-8 gene expression was suppressed by either concomitant treatment with actinomycin-D or cycloheximide, yet specific neutralizing antibodies directed against either IL-1 beta or tumor necrosis factor (TNF)-alpha failed to alter adherence-induced steady-state IL-8 mRNA levels. These data support the hypothesis that PBMC adherence is an important signal for the production of IL-8, and may be essential to the development of the inflammatory response through the elicitation of PMN.

Blood Proteins↗
PubMed1991

Pulmonary fibroblast expression of interleukin-8: a model for alveolar macrophage-derived cytokine networking.

The pulmonary fibroblast's (PF) unique location allows it to communicate in a bidirectional fashion between the vascular compartment and alveolar airspace, placing it in a strategic position for the elicitation of inflammatory leukocytes into the lung. In this study, we demonstrate that PF may contribute to pulmonary inflammation through the production of a potent neutrophil chemotactic factor, interleukin (IL)-8. PF-derived IL-8 expression was dependent upon stimulation by either tumor necrosis factor (TNF) or IL-1 but not lipopolysaccharide (LPS). Both TNF and IL-1 stimulation of PF resulted in a time- and dose-dependent expression of steady-state levels of mRNA, antigen, and specific chemotactic activity consistent with IL-8. Because it was apparent that cytokine networking may exist in the lung between alveolar macrophage (AM)-derived cytokines and the production of PF-derived IL-8, we next examined an in vitro model of cellular communication within the lung. We determined that LPS-stimulated AM-conditioned media induced significant levels of PF-derived IL-8 mRNA, which was inhibited by preincubation with specific neutralizing TNF and IL-1 beta antibodies. Furthermore, when AM were directly co-cultured with PF and stimulated with LPS, the kinetic analysis of PF-derived antigenic expression of IL-8 was shifted toward the right. This suggested that PF-derived IL-8 expression in co-culture was first dependent upon activation of the AM by LPS and subsequent elaboration of macrophage inflammatory mediators. These data provide evidence that cytokine networking between AM and PF may be operative in the lung, culminating in the generation of IL-8 and elicitation of inflammatory leukocytes.

Antibodies↗
PubMed1991

Interleukin-8 gene expression from human alveolar macrophages: the role of adherence.

The human alveolar macrophage (AM) is an important immune effector cell of the lung, as this cell possesses potent antimicrobial activities and has the ability to present antigen. In addition, the Am can secrete a number of regulatory and chemotactic cytokines in response to both endogenous and exogenous stimuli. In this study, we demonstrate that the adherence of AM to plastic or cellular substrates is an important activation event leading to the gene expression of novel chemotactic cytokine interleukin (IL)-8. The culturing of AM on plastic induced the time-dependent accumulation of IL-8 mRNA. In addition, adherence of these cells induced the gene expression of the proinflammatory cytokines tumor necrosis factor-alpha and IL-1 beta. This adherence phenomenon was not specific to plastic, as AM cultured on collagen- or fibronectin-coated plates also expressed IL-8 mRNA upon adherence. The adherence of Am resulted in the induction of de novo IL-8 mRNA synthesis, as this mRNA accumulation was completely abrogated by actinomycin D. Adherence-induced IL-8 mRNA expression was not altered by cycloheximide, suggesting that de novo or ongoing protein synthesis was not required for induction of IL-8 message. Adherence of AM to plastic not only upregulated IL-8 mRNA levels but also induced the production of extracellular IL-8 immunoreactive protein. Both adherent and nonadherent AM treated with lipopolysaccharide generated substantial amounts of IL-8 mRNA. Adherence and lipopolysaccharide, however, acted in a synergistic fashion to dramatically augment the production of extracellular IL-8 from these cells. Our findings would suggest that AM adherence is an important macrophage-activating event that may play a critical role in the modulation of lung inflammatory responses.

Base Sequence↗
PubMed1991

Elevated serum levels of tumor necrosis factor-alpha after bronchoscopy and bronchoalveolar lavage.

Fiberoptic bronchoscopy and bronchoalveolar lavage are often followed by the development of fever and other influenza-like symptoms. We report the onset of these symptoms in a healthy volunteer following bronchoscopy and bronchoalveolar lavage; the symptoms were temporally associated with the dramatic elevation of serum levels of tumor necrosis factor. Our observations suggest that tumor necrosis factor may be involved in mediating fever and other influenza-like symptoms occurring after bronchoscopy.

Bronchoalveolar Lavage Fluid↗
PubMed1991

Chemotactic cytokine (IL-8 and MCP-1) gene expression by human whole blood.

The salient features of systemic or local inflammation are the myriad of cellular and humoral interactions that result in elicitation of inflammatory leukocytes. In this study using specialized connective tissue, intact whole blood, we demonstrate the gene expression of two novel chemotactic factors. The buffy-coat cellular expression of neutrophil chemotactic/activating factor/interleukin 8 (IL-8) and monocyte chemotactic/activating protein (MCP-1) mRNA were time and dose-dependent in response to either lipopolysaccharide or zymosan stimulation. This system with the complexity of tissue provides a unique model for the determination of chemotactic cytokine gene expression.

Antigens↗
PubMed1990

Interleukin-8 production in red blood cell incompatibility.

Hemolytic transfusion reactions (HTR) are characterized by fever, shock, organ system failure, intravascular coagulation, and possibly death. The same findings may be associated with sepsis. Neutrophils have been implicated in the pathogenesis of HTR, although a mechanism for neutrophil activation has not been shown. In addition, the possible role that cytokines may play in HTR has not been investigated. We show that interleukin-8 (IL-8), a cytokine with chemotactic and neutrophil-activation properties, is produced in whole blood following addition of ABO-incompatible red blood cells, in a dose- and time-dependent manner related to the degree of hemolysis, and is inhibited by inactivation of complement. IL-8 production is accompanied by increased gene expression in the buffy coat. This observation has implications for the understanding of the pathogenesis of and for the treatment of HTR.

ABO Blood-Group System↗
PubMed1990

Human neutrophils exhibit disparate chemotactic factor gene expression.

The evolution of acute inflammation from initiation through resolution is associated with the changing character of the infiltrating leukocytes. Recruitment of these leukocytes is dependent upon the generation of chemotactic factors that have either global or specific activity for a particular leukocyte. In this manuscript we present data demonstrating that human neutrophils can express mRNA for neutrophil chemotactic factor/interleukin 8 (IL-8), but fail to express mRNA for monocyte chemotactic protein (MCP-1). The expression of IL-8 was observed upon adherence or in response to stimulation with lipopolysaccharide. Maximal IL-8 antigenic production was noted at 24 hrs. These studies demonstrate a disparate expression of chemotactic cytokines by neutrophils.

Acute Disease↗