Search PubMed⌕ Search

Biomedical subjects

A Walz

Publications and source records attributed to A Walz.

At least 55 records · Page 3Linked to original sources
PubMed1994

Interleukin-8 processing by neutrophil elastase, cathepsin G and proteinase-3.

Activated neutrophils secrete two forms of IL-8 with 77 and 72 amino acids, IL-8(77) and IL-8(72), along with proteinases that could process these cytokines. Significant conversion of IL-8(77) to more potent, N-terminally truncated forms was observed upon incubation with neutrophil granule lysates and purified proteinase-3. IL-8(72) was considerably more resistant to proteolytic processing than IL-8(77). The present observations indicate that neutrophil proteinases released in inflamed tissues convert IL-8 to more active forms and therefore tend to conserve or enhance, rather than decrease IL-8 activity.

Amino Acid Sequence↗
PubMed1994

Functional and ligand binding specificity of the rabbit neutrophil IL-8 receptor.

IL-8 mediates migration and activation of neutrophils. This study describes the functional and ligand binding specificity of the human intercrine peptides IL-8, neutrophil-activating peptide 2 (NAP-2), melanoma growth stimulatory activity (GRO), and platelet factor 4 (PF4) to rabbit neutrophils and mammalian cell lines transfected with rabbit IL-8 receptor cDNA (F3R). Rabbit neutrophil membranes bound 125I-labeled IL-8 and 125I-labeled NAP-2 but did not bind 125I-labeled GRO or 125I-labeled PF4. Rabbit neutrophils mobilized intracellular Ca2+ in response to IL-8 and NAP-2 but not to GRO or PF4. Monkey kidney cells (COS-7) and hamster lung fibroblasts (CCL-39) were transiently and stably transfected with the rabbit neutrophil IL-8 receptor F3R cDNA. COS-7 cells transfected with F3R cDNA bound 125I-labeled IL-8 but did not bind other IL-8-related peptides such as 125I-labeled NAP-2, 125I-labeled GRO, or 125I-labeled PF4. Furthermore, bound 125I-labeled IL-8 was only displaced by unlabeled IL-8 but not by unlabeled NAP-2, GRO alpha, or PF4. Consistent with this observation, stably transfected CCL 39 cells expressing F3R cDNA mobilized Ca2+ only in response to IL-8. We conclude that F3R cDNA encodes a functional IL-8 receptor isotype with strict ligand binding specificity for IL-8, that rabbit neutrophils do not bind human GRO alpha, and it is suggested that rabbit neutrophils contain in addition to the F3R protein another IL-8 receptor isotype with broad ligand specificity or a distinct NAP-2 receptor.

Animals↗
PubMed1994

Substrate-dependent interactions of leech microglial cells and neurons in culture.

The principal aim of the present experiments has been to analyze the properties of microglial cells and their role in nerve regeneration. In the leech, damage to the CNS has been shown to be followed by accumulation of laminin and microglial cells at the site of injury (Masuda-Nakagawa et al., 1990. Proc. R. Soc. Lond. B. 241:201-206; and 1993. Proc. Natl. Acad. Sci. USA 90:4966-4970). Procedures were devised for isolating these small, wandering cells from the CNS of the leech. In culture, they were reliably identified by their sizes, shapes, and phagocytotic activity. Their morphology, motility, and interactions with neurons were influenced by the substrate molecules on which they were plated. On the plant lectin concanavalin A (Con A) microglia had a rounded shape and remained stationary. By contrast on extracts of leech extracellular matrix (ECM) enriched with laminin the cells were mobile and spindle-shaped with long processes. On Con A, neuronal growth cones avoided microglial cells, whereas on ECM extract the presence of a microglial cell did not influence neurite growth. Microglial cells showed immunoreactivity on both substrates when stained with a monoclonal antibody against leech laminin. Together these results suggest that microglial cells are influenced in their properties by molecules in the environment and that they could contribute to neuronal outgrowth at the site of an injury.

Animals↗
PubMed1994

Regulation of chemokine production by the oxidative metabolism of L-arginine in a human mixed lymphocyte reaction.

Previous studies have shown that during the development of a mixed lymphocyte reaction (MLR) levels of the chemotactic cytokines IL-8 and MCP-1 (members of the C-X-C and C-C supergene families, respectively) increase in a time-dependent fashion, and that the production of these chemokines correlates with the magnitude of responsiveness to alloantigen. Furthermore, the responsiveness to alloantigen in the context of a MLR has been shown to be regulated by the oxidative metabolism of L-arginine. We postulated that competitive antagonism of the L-arginine metabolic pathway in a human MLR may alter the production of members of the C-C and C-X-C chemokine families. To test this hypothesis, mononuclear cells were isolated from healthy individuals and subjected to a one-way MLR in the presence or absence of varying concentrations of an L-arginine competitive inhibitor, NG-methyl-L-arginine (NMA: 50 to 500 microM). When the MLR was performed in the presence of NMA (500 microM), the production of IL-8 increased twofold (P < 0.05) and ENA-78 increased fivefold (P < 0.05), while MCP-1 and MIP-1 alpha were not significantly altered. These findings suggest that NMA, an inhibitor of the L-arginine metabolic pathway, may regulate the production of specific C-X-C chemokines, IL-8 and ENA-78, during a MLR. In contrast, the production of MCP-1 and MIP-1 alpha, members of the C-C chemokine family, does not appear to be regulated by this inhibitor of the oxidative metabolism of L-arginine in the context of a MLR.

Arginine↗
PubMed1994

Elevated IL-8 and MCP-1 in the bronchoalveolar lavage fluid of patients with idiopathic pulmonary fibrosis and pulmonary sarcoidosis.

The potential for interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) to induce neutrophil and mononuclear phagocyte accumulation in the lungs of patients with pulmonary sarcoidosis and idiopathic pulmonary fibrosis (IPF) was investigated. Bronchoalveolar lavage (BAL) fluids from 12 patients with IPF and 15 with sarcoidosis were concentrated by reversed-phase chromatography, and their IL-8 and MCP-1 concentrations assessed by enzyme-linked immunosorbent assay (ELISA), chemotaxis, and enzyme-releasing assays with monocytes and neutrophils. ELISA revealed significantly elevated concentrations of MCP-1 (20.1 ng/mg albumin) in the BAL fluids of patients with pulmonary sarcoidosis and those with IPF (41.8 ng/mg) in comparison to 11 normal individuals (4.24 ng/mg) and 15 patients with chronic bronchitis (CB) (5.16 ng/mg). Similarly, the chemotactic activity for monocytes (MCP-1 equivalent) was strongly increased in patients with sarcoidosis (86.03 ng/mg) as well as in those with IPF (54.47 ng/mg). The chemoattractant activity of normal individuals and CB patients was 7- or 3-fold lower, respectively. Patients with IPF and sarcoidosis also had elevated IL-8 levels (15.5 and 26.0 ng/mg, respectively; normals: 2.14 ng/mg; and CB patients: 4.23 ng/mg) and greater neutrophil chemotaxis (60.25 and 49.68 ng/mg, respectively; normals: 0.35 ng/mg; and CB patients: 11.06 ng/mg). These data suggest that increased levels of both MCP-1 and IL-8 may be characteristic for sarcoidosis or IPF. It appears likely that both of these chemoattractants contribute to the influx of monocytes and neutrophils into the pulmonary alveolus and interstitium in these diseases.

Adult↗
PubMed1994

Epithelial neutrophil activating peptide-78: a novel chemotactic cytokine for neutrophils in arthritis.

We and others have shown that cells obtained from inflamed joints of rheumatoid arthritis (RA) patients produce interleukin-8, a potent chemotactic cytokine for neutrophils (PMNs). However, IL-8 accounted for only 40% of the chemotactic activity for PMNs found in these synovial fluids. Currently, we have examined the production of the novel PMN chemotactic cytokine, epithelial neutrophil activating peptide-78 (ENA-78), using peripheral blood, synovial fluid, and synovial tissue from 70 arthritic patients. RA ENA-78 levels were greater in RA synovial fluid (239 +/- 63 ng/ml) compared with synovial fluid from other forms of arthritis (130 +/- 118 ng/ml) or osteoarthritis (2.6 +/- 1.8 ng/ml) (P < 0.05). RA peripheral blood ENA-78 levels (70 +/- 26 ng/ml) were greater than normal peripheral blood levels (0.12 +/- 0.04 ng/ml) (P < 0.05). Anti-ENA-78 antibodies neutralized 42 +/- 9% (mean +/- SE) of the chemotactic activity for PMNs found in RA synovial fluids. Isolated RA synovial tissue fibroblasts in vitro constitutively produced significant levels of ENA-78, and this production was further augmented when stimulated with tumor necrosis factor-alpha (TNF-alpha). In addition RA and osteoarthritis synovial tissue fibroblasts as well as RA synovial tissue macrophages were found to constitutively produce ENA-78. RA synovial fluid mononuclear cells spontaneously produced ENA-78, which was augmented in the presence of lipopolysaccharide. Immunohistochemical localization of ENA-78 from the synovial tissue of patients with arthritis or normal subjects showed that the predominant cellular source of this chemokine was synovial lining cells, followed by macrophages, endothelial cells, and fibroblasts. Synovial tissue macrophages and fibroblasts were more ENA-78 immunopositive in RA than in normal synovial tissue (P < 0.05). These results, which are the first demonstration of ENA-78 in a human disease state, suggest that ENA-78 may play an important role in the recruitment of PMNs in the milieu of the inflamed joint of RA patients.

Arthritis↗
PubMed1994

Bovine ENA, a new monocyte-macrophage derived cytokine of the interleukin-8 family. Structure, function, and expression in acute pulmonary inflammation.

A novel bovine neutrophil-activating peptide, bovine ENA (boENA), was identified in the conditioned media of endotoxin-stimulated bovine monocytes and alveolar macrophages. The chemotactic peptide was purified to homogeneity from conditioned media by cation-exchange chromatography and several steps of reversed-phase high-performance liquid chromatography. The partial amino acid sequence of boENA was: VVRELRCVCLTTTPGIHPKTVSDLQVIAAGPVCSKVEVIATLKNGXXV. Its cysteine molecules are positioned identically to those of the C-X-C family of human proinflammatory peptides. BoENA shows structural (73% identity in amino acid sequence) and functional homology to human ENA-78, a product of the human type II epithelial cell line A549, as demonstrated in assays for chemotaxis, aggregation, shape change, and a rise in intracellular free calcium. The immunohistochemical identification of boENA in the hyperplastic type II alveolar epithelial cells and in pulmonary alveolar leukocytes of pneumonic bovine lungs strongly supports a role for ENA-78 in the genesis of pulmonary inflammation.

Acute Disease↗
PubMed1993

Interleukin-8 and development of adult respiratory distress syndrome in at-risk patient groups.

Neutrophils have been implicated in the pathogenesis of the adult respiratory distress syndrome (ARDS). We have measured concentrations of the neutrophil attractant interleukin-8 in blood and bronchoalveolar lavage fluid (BAL) from patients at risk of ARDS. We studied 29 patients from three groups at risk of developing ARDS: multiple trauma (n = 16), perforated bowel (n = 6), and pancreatitis (n = 7). ARDS developed in 7 of these patients. Interleukin-8 in BAL and blood samples taken on initial hospital presentation was measured by a sandwich enzyme-linked immunosorbent assay. The mean BAL interleukin-8 concentration was significantly higher for the patients who subsequently progressed to ARDS than for the non-ARDS group (3.06 [SE 2.64] vs 0.053 [0.010] ng/mL, p = 0.0006). There was no difference between the groups in plasma interleukin-8 (6.23 [2.60] vs 5.12 [2.22] ng/mL, p = 0.31). Immunocytochemistry suggested that the alveolar macrophage is an important source of interleukin-8 at this early stage in ARDS development. This study provides evidence of a relation between the presence of interleukin-8 in early BAL samples and the development of ARDS. The early appearance of interleukin-8 in BAL of patients at risk of ARDS may be an important prognostic indicator for the development of the disorder and reinforces the likely importance of neutrophils and the effects of their accumulation and activation in the pathogenesis of many cases of ARDS.

Adolescent↗
PubMed1993

In vitro and in vivo activity and pathophysiology of human interleukin-8 and related peptides.

Interleukin-8 is a member of a novel cytokine family and has been found to be an activator and attractant for human neutrophils in vitro. The in vivo activity was tested in experimental animal models by intradermal and intravenous administration of IL-8. Intradermal administration of human IL-8 in rats induces a rapid and concentration-dependent neutrophil infiltration, which peaks 4 hr after IL-8 application. Injection of GRO-alpha induces a similar chemotactic response, whereas neutrophil-activating peptide-2 was significantly less active. When injected intravenously into rabbits, IL-8 induced neutrophil sequestration in the lungs and, following repeated injections, caused septal and intraalveolar edema and lung damage resembling that seen in adult respiratory distress syndrome. The fact that IL-8 is induced and secreted from many different cell types suggests its involvement in a variety of physiologic and pathologic conditions as a neutrophil chemoattractant and, possibly, as an activator of other neutrophil responses.

Animals↗
PubMed1992

Leukoregulin, a T cell-derived cytokine, induces IL-8 gene expression and secretion in human skin fibroblasts. Demonstration and secretion in human skin fibroblasts. Demonstration of enhanced NF-kappa B binding and NF-kappa B-driven promoter activity.

It was shown previously that leukoregulin (LR), a T cell-derived cytokine with unique antitumor properties, modulates fibroblast functions in vitro, including prostaglandin production, matrix synthesis, and protease gene expression. Here, we have focused on the ability of LR to modulate IL-8 gene expression in human dermal fibroblasts. Using a specific ELISA, we demonstrated a dose-dependent enhancement of IL-8 production by LR, accompanied by a parallel elevation of the corresponding mRNA levels, as measured by Northern hybridizations. Maximum accumulation of IL-8 mRNA was observed after 6 h of incubation with LR, and the elevation persisted over 24 h. Inhibition of protein synthesis by cycloheximide resulted in superinduction of IL-8 mRNAs by LR. Dexamethasone, all-trans-retinoic acid, and TGF-beta 1 failed to counteract the effect of LR on IL-8 gene expression. Transient cell transfections with an IL-8 promoter/CAT reporter gene construct showed a dose-dependent enhancement of the promoter activity by LR, suggesting transcriptional regulation. Gel shift assays with oligonucleotides containing the consensus NF-kappa B binding sequences of the IL-8 and Ig kappa light chain genes showed enhanced binding activity in nuclear extracts from cells incubated with LR. Transient transfection experiments using a NF-kappa B/SV2 promoter-CAT reporter gene construct showed enhanced CAT activity by LR. Taken together, these data suggest that LR may up-regulate IL-8 gene expression by activation of the binding of NF-kappa B to the corresponding cis-acting element in the IL-8 promoter. Our results demonstrate that LR, together with IL-1 and TNF-alpha, could participate in the recruitment of neutrophils to the sites of inflammation by induction of IL-8 production in fibroblasts.

Antineoplastic Agents↗
PubMed1992

Activation of human basophils through the IL-8 receptor.

IL-8 and its structural analogs derived from blood platelets have been proposed as stimuli of IgE-independent basophil activation. In order to clarify the mechanism of action of these peptides, we examined the effects of pure IL-8, connective tissue-activating peptide III (CTAP-III), neutrophil-activating peptide 2 (NAP-2), and platelet factor 4 (PF-4) on blood basophils with and without pretreatment by IL-3, which modulates mediator release. After pretreatment with IL-3, significant histamine release was observed with 10(-8) M and 10(-7) M IL-8 and 10(-7) M NAP-2, but not with the other peptides. At higher concentrations (10(-6) M), however, all IL-8 analogs, as well as the unrelated cationic peptides poly-D-lysine, histone VS, and lysozyme, induced histamine release to variable degrees. Binding and competition studies with [125I]IL-8 revealed specific IL-8R on basophils from a patient with chronic myelogenous leukemia and normal individuals. From 3500 to 9600 receptors with a mean Kd value of 0.15 nM were found on average per chronic myelogenous leukemia and normal basophil, respectively. NAP-2 weakly competed for IL-8 binding. IL-8 and, to a lesser extent, NAP-2 led to a transient rise of cytosolic free calcium concentration ([Ca2+]i), which was independent of a preexposure to IL-3. IL-8 prevented the [Ca2+]i rise induced by NAP-2, but did not influence [Ca2+]i responses to other agonists, e.g. C5a, C3a, or platelet-activating factor. IL-8 induced [Ca2+]i changes and histamine release in IL-3-primed basophils were pertussis toxin sensitive. CTAP-III or PF-4 did not compete for IL-8 binding, did not induce [Ca2+]i changes, and did not influence the [Ca2+]i response to IL-8 and NAP-2. This study shows that IL-8 and NAP-2 activate human basophils by a receptor-mediated mechanism similar to that operating in neutrophils. At high concentrations histamine release can also be induced by cationic peptides by a mechanism that does not involve the IL-8R, and probably depends on cationic interactions.

Amino Acid Sequence↗
PubMed1992

Interleukin-8 is produced in neoplastic and infectious diseases of the human central nervous system.

The presence of interleukin-8 (IL-8), a leukocyte chemotactic factor, was examined in primary and metastatic central nervous system tumors and in nonneoplastic acute meningoencephalitides. In vitro: (a) 11 of 12 glioblastoma cell lines constitutively expressed IL-8 mRNA; (b) 5 of 6 of these cell lines secreted IL-8 protein as detected by enzyme-linked immunosorbent assay and a glucosaminidase release bioassay; and (c) IL-1 beta or tumor necrosis factor was able to augment both IL-8 mRNA steady state levels and protein secretion of all cell lines tested except IN-319. IL-8 was also found in vivo. (a) IL-8 poly A+ mRNA was detected in 2 of 2 low grade astrocytomas, 1 of 2 anaplastic astrocytomas, and 6 of 6 glioblastomas. (b) IL-8 protein was present in the cyst fluid of 1 of 4 low grade astrocytomas, 1 anaplastic astrocytoma, 2 of 2 glioblastomas, 1 oligodendroglioma grade III, and one central nervous system cervical carcinoma metastasis. (c) The cerebrospinal fluid of 3 of 4 metastatic lymphomas, 2 of 16 glioblastomas, 1 of 2 low grade astrocytomas, but none of 3 anaplastic astrocytomas and none of 9 meningiomas contained IL-8. The presence of IL-8 was not restricted to central nervous system tumors as 2 of 2 bacterial meningitis and 5 of 5 acute viral meningitis patients contained considerable IL-8 levels in the cerebrospinal fluid. (d) Immunohistochemical analysis showed IL-8 immunoreactivity in perivascular tumor cells in 11 of 15 glioblastoma sections. These data suggest that IL-8 secretion could be a key factor involved in the determination of the lymphoid infiltrates observed in brain tumors and the development of cerebrospinal fluid pleocytosis in meningoencephalitides.

Astrocytoma↗
PubMed1992

The detection of a novel neutrophil-activating peptide (ENA-78) using a sensitive ELISA.

Neutrophil elicitation into tissue is an essential element of the host defense in response to various stimuli, including, tissue injury, infection, or cancer. This event has gained renewed interest with the discovery of a family of small polypeptides (less than 10 kD). The salient features of these cytokines are the presence of four cysteine amino acids (first two separated by one amino acid; C-X-C) and their ability to induce neutrophil chemotaxis and activation. Recently, our laboratories have discovered a new member of this C-X-C chemotactic cytokine supergene family, neutrophil-activating peptide, ENA-78. ENA-78 shares significant amino acid sequence homology with neutrophil activating peptide-2 (NAP-2; 53%), growth regulated oncogene/melanoma growth stimulatory activity (GRO alpha; 52%), and IL-8 (22%). In addition, ENA-78 appears to activate neutrophils through the IL-8 receptor. Since both in vitro and in vivo biological fluids may contain an array of chemotactic cytokines that may be relevant to the activation and chemotaxis of neutrophils, we have developed a highly specific and sensitive sandwich ELISA for the detection of ENA-78.

Chemokine CXCL5↗
PubMed1992

Functional analysis of monocyte activity through synthesis patterns of proinflammatory cytokines and neopterin in patients in surgical intensive care.

This study was designed to further differentiate monocyte behavior in critically ill patients with operative or accidental trauma. The patient population studied consisted of 39 patients (17 patients undergoing elective surgery [ES], seven patients with major multiple injuries [MI], and 15 patients in an acute septic state [S]). Immunologic parameters assessed included monocyte phenotyping with the monoclonal antibody LeuM3, measurement of the cytokines interleukin (IL)-1, IL-6, and IL-8 in lipopolysaccharide-stimulated in vitro cultures of mononuclear leukocytes (PBMCs), and determination of neopterin in gamma-interferon-stimulated in vitro cultures and corresponding serum samples. Serum neopterin levels were very high in S patients (89.0 nmol/L; p less than 0.05) compared with control values (4.6 nmol/L), with a rise to 16.4 nmol/L in ES patients on day 7 and 13.4 nmol/L in MI patients on day 7. The concentrations of gamma-interferon-induced neopterin in the supernatants of the PBMC cultures were elevated in all patient groups. Severe impairment of IL-1 synthesis was seen in MI and S patients. IL-8 synthesis (818 +/- 150 units/ml, control value) was also suppressed (p less than 0.05) in MI patients; the values were 135 +/- 65 units/ml on day 1,231 +/- 110 units/ml on day 3,347 +/- 131 units/ml on day 7, and 355 +/- 107 units/ml in S patients. The kinetic patterns of synthesis were comparable for IL-1 and IL-8 in all patient groups. Lipopolysaccharide-induced IL-6 synthesis (9.4 +/- 1.5 x 10(3) units/ml, control value) was significantly elevated in the PBMC cultures of all patient groups, with the exception of the early phase after accidental trauma. Maximum amounts of IL-6 synthesis after surgery were 19.6 +/- 7 x 10(3) units/ml in S patients and 19.0 +/- 2.2 x 10(3) units/ml in ES patients. These results demonstrate (1) the impairment of the functional capacity of circulating monocytes and (2) that the degree of functional impairment is proportional to the severity of the injury.

Adolescent↗