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Biomedical subjects

R G Crystal

Publications and source records attributed to R G Crystal.

At least 199 records · Page 11Linked to original sources
PubMed1993

In vivo gene transfer and expression in normal uninjured blood vessels using replication-deficient recombinant adenovirus vectors.

Replication-deficient recombinant adenovirus vectors do not require target cell replication for transfer and expression of exogenous genes and thus may be useful for in vivo gene therapy in the endothelium. To evaluate the feasibility of adenovirus-mediated gene transfer in vivo in normal intact blood vessels, adenovirus vectors containing the Escherichia coli lacZ gene or a human alpha 1-antitrypsin (alpha 1AT) cDNA were injected in vivo into the lumen of an occluded vessel segment of sheep jugular vein and/or carotid artery. After 15 minutes of incubation, circulation was restored; the vessels were harvested 1-28 days later and evaluated for gene transfer and expression. Three days after in vivo exposure to the lacZ adenovirus vector, the endothelium of jugular veins and carotid arteries expressed beta-galactosidase. Exposure of jugular veins and carotid arteries in vivo to the alpha 1AT adenovirus vector resulted in the expression of alpha 1AT mRNA transcripts detected by Northern analysis and in the synthesis and secretion of alpha 1AT detected by ex vivo [35S]methionine labeling. Expression with the adenovirus vectors was efficient and easily detectable 1-14 days after injection, with maximum expression at 7 days. Expression was no longer evident at 28 days. Thus, adenovirus vectors are capable of transferring exogenous genes to the endothelium of normal arteries and veins with expression for at least 2 weeks, suggesting that these vectors have the potential for a variety of cardiovascular experimental and clinical applications.

Adenoviridae↗
PubMed1993

Efficient gene transfer into myocardium by direct injection of adenovirus vectors.

Previous studies have established that gene transfer into myocardial cells in vivo is detectable after direct injection of plasmid DNA. Recently, adenovirus vectors have been shown to provide an efficient method for gene transfer into a wide range of tissues. Therefore, this study sought to assess the efficiency and stability of adenovirus-mediated gene transfer into myocardium and to compare this method with that using plasmid-based gene transfer techniques. Adult rats underwent myocardial injection via a subdiaphragmatic approach. Gene transfer efficiency was compared using direct injection of an adenovirus vector encoding for the marker gene beta-galactosidase (beta-gal), a control adenovirus vector encoding for the cystic fibrosis transmembrane conductance regulator gene, a plasmid encoding for beta-gal, or a control plasmid. Hearts infected with an adenovirus vector containing the beta-gal gene showed significantly increased beta-gal enzymatic activity compared with hearts injected with beta-gal plasmid. Histological examination revealed that cardiac myocytes were the target of adenovirus-mediated gene transfer. A time course of gene expression showed that beta-gal enzymatic activity peaked during the first week following injection. Adenovirus vectors provide an efficient but transient method for in vivo gene expression in myocardium.

Adenoviridae↗
PubMed1993

Pharmacokinetics of recombinant secretory leukoprotease inhibitor aerosolized to normals and individuals with cystic fibrosis.

Recombinant secretory leukoprotease inhibitor (rSLPI), a recombinant form of a natural airway inhibitor of neutrophil elastase (NE), is a potential therapeutic agent for cystic fibrosis (CF), a condition characterized by airway derangement mediated in part by the large burden of NE on the CF respiratory epithelial surface. After in vitro studies that demonstrated that aerosolized rSLPI retains its form and function, rSLPI was administered via aerosol to normal individuals and individuals with CF to determine the pharmacokinetics of in vivo rSLPI augmentation of the anti-NE defenses of the respiratory epithelial surface. After rSLPI aerosolization to normal individuals (100 mg single dose or 100 mg twice daily for 1 wk) there was a marked increase in SLPI levels and anti-NE capacity in airway epithelial lining fluid (ELF) at 1 h, diminishing gradually over 4 to 12 h. Interestingly, the ELF SLPI levels and anti-NE capacity achieved 12 h after 1 wk of rSLPI aerosols were no different than those 12 h after a single dose of rSLPI, suggesting that rSLPI does not accumulate on the respiratory epithelial surface after aerosolization. The ability of rSLPI to suppress NE in vivo was evaluated by aerosolization of rSLPI to individuals with CF, first as an escalating dose to assess safety, and then at doses of 100 mg twice daily for 1 wk or 50 mg twice daily for 2 wk.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗
PubMed1993

Diversity of airway epithelial cell targets for in vivo recombinant adenovirus-mediated gene transfer.

A variety of pulmonary disorders, including cystic fibrosis, are potentially amenable to treatment in which a therapeutic gene is directly transferred to the bronchial epithelium. This is difficult to accomplish because the majority of airway epithelial cells replicate slowly and/or are terminally differentiated. Adenovirus vectors may circumvent this problem, since they do not require target cell proliferation to express exogenous genes. To evaluate the diversity of airway epithelial cell targets for in vivo adenovirus-directed gene transfer, a replication deficient recombinant adenovirus containing the Escherichia coli lacZ (beta-galactosidase [beta-gal]) gene (Ad.RSV beta gal) was used to infect lungs of cotton rats. In contrast to uninfected animals, intratracheal Ad.RSV beta gal administration resulted in beta-gal activity in lung lysate and cytochemical staining in all cell types forming the airway epithelium. The expression of the exogenous gene was dose-dependent, and the distribution of the beta-gal positive airway epithelial cells in Ad.RSV beta gal-infected animals was similar to the normal cell differential of the control animals. Thus, a replication deficient recombinant adenovirus can transfer an exogenous gene to all major categories of airway epithelial cells in vivo, suggesting that adenovirus vectors may be an efficient strategy for in vivo gene transfer in airway disorders such as cystic fibrosis.

Adenoviruses, Human↗
PubMed1993

Aerosolization of superoxide dismutase. Augmentation of respiratory epithelial lining fluid antioxidant screen by aerosolization of recombinant human Cu++/Zn++ superoxide dismutase.

Various human pulmonary diseases are characterized by an increased oxidant burden on the respiratory epithelial surface. As a step toward developing a therapy to augment the antioxidant defenses of respiratory epithelial lining fluid (ELF) of the human lung, we have evaluated the feasibility of aerosolizing a human protein antioxidant to the respiratory epithelial surface of an experimental animal sufficiently large to permit repetitive sampling of ELF. To accomplish this, recombinant human Cu++/Zn++ superoxide dismutase (rSOD) was aerosolized to sheep, and the levels of human superoxide dismutase (SOD) and antisuperoxide anion (O2.-) capacity were quantified in ELF over time. In vitro aerosolization did not alter the specific activity of rSOD (p > 0.5). In vivo aerosolization of rSOD (100 mg) to sheep (n = 7) resulted in peak amounts of human Cu++/Zn++ SOD in ELF of 3.1 +/- 0.6 mumol/L, with a parallel increase in the anti-O2.- capacity of ELF. For the duration of the study (5 h), levels of SOD and anti-O2.- in ELF remained elevated, with a value 50 percent of the peak at 5 h. Aerosolization of phosphate-buffered saline (n = 5) had no effect on SOD or anti-O2.- levels in ELF. In animals receiving rSOD, there was no change in the specific activity of SOD recovered in ELF compared to the starting material (p > 0.4). We conclude that rSOD can be delivered by aerosol to the ELF of a large animal with preservation of specific activity and that a substantial increase in both the amount of SOD and the anti-O2.- capacity can be achieved for a period of time applicable to human therapy, supporting the rationale for evaluation of rSOD aerosol as an antioxidant in human pulmonary disease.

Aerosols↗
PubMed1993

Gene therapy for pulmonary diseases.

The common fatal hereditary disorders, alpha 1-antitrypsin (alpha 1AT) deficiency and cystic fibrosis (CF), are clinical models for the common lung diseases, emphysema and chronic bronchitis, respectively. Both are potentially amenable to therapeutic intervention by gene therapy, in which the relevant gene is used to modify cells of the affected individual. Although the gene therapy strategies for these diseases are conceptually quite different, a promising approach for both is the in vivo administration of a recombinant replication deficient adenovirus vector containing a normal copy of the abnormal gene. If the goal is to express the normal extracellular anti-protease alpha 1 AT, the route of administration could be directly into the lung, liver or vascular endothelium. If the goal is to express the normal transmembrane protein defective in CF epithelial cells, the new gene will need to be delivered directly to the affected cells. The feasibility of these approaches has been demonstrated in vitro and in vivo in experimental animals.

Adenoviridae↗
PubMed1992

Tumor necrosis factor modulation of expression of the cystic fibrosis transmembrane conductance regulator gene.

Based on the knowledge that expression of the cystic fibrosis transmembrane conductance regulator (CFTR) gene can be modulated at the transcriptional level, and that the CFTR gene promoter contains sequences homologous to elements in other promoters that respond to tumor necrosis factor-alpha (TNF), we evaluated the hypothesis that TNF might modulate CFTR gene expression in epithelial cells. Studies with HT-29 cells, a colon epithelium-derived tumor cell line known to express the CFTR gene, demonstrated that TNF downregulated CFTR mRNA transcript levels in a dose- and time-dependent fashion. Interestingly, nuclear run-on analyses demonstrated that TNF did not affect the rate of transcription of CFTR gene, but exposure of the cells to TNF did modify the stability of CFTR mRNA transcripts, resulting in a mRNA half-life that was reduced to 65% of the resting level. These observations suggest that CFTR gene expression can be modulated by TNF, at least in part, at the posttranscriptional level.

Blotting, Northern↗
PubMed1992

Expression of the cystic fibrosis transmembrane conductance regulator gene can be regulated by protein kinase C.

Epithelial cells utilize at least two types of apical Cl- channels, the cAMP-activated cystic fibrosis transmembrane conductance regulator (CFTR) and the Ca2+/calmodulin-dependent Cl- channel. While phorbal ester (PMA) activates only CFTR-dependent Cl- secretion and the Ca2+ ionophore A23187 only the Ca2+/calmodulin-dependent Cl- secretion, PMA and A23187 share the ability to down-regulate expression of the CFTR gene at the transcriptional level. Since both PMA and A23187 can activate protein kinases, we hypothesized that protein kinase pathways may be involved in the regulation of CFTR gene expression. Exposure of HT-29 human colon carcinoma cells to the protein kinase C activator SC9 down-regulated CFTR mRNA levels in a dose-dependent fashion, similar to that seen with PMA. The reduction in CFTR transcript levels by SC9 and PMA was blocked by H7, an inhibitor of protein kinases. In a similar fashion, the down-regulation of CFTR transcript levels by A23187 was blocked by H7 as well as staurosporine, another protein kinase inhibitor. Interestingly, both H7 and staurosporine themselves increased CFTR mRNA levels. Quantification of CFTR gene transcription rate showed a reduction by SC9 (similar to that with PMA and A23187) that was prevented by H7 and that H7 by itself increased CFTR transcription. Together, these observations suggest that protein kinase pathways, likely including protein kinase C, are involved in the regulation of CFTR gene expression, with activation or inhibition of protein kinase activity down-regulating or up-regulating CFTR gene expression, respectively.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Adenovirus-mediated transfer of a recombinant human alpha 1-antitrypsin cDNA to human endothelial cells.

To evaluate the feasibility of using a replication-deficient recombinant adenovirus to transfer human genes to the human endothelium, human umbilical vein endothelial cells were infected in vitro with adenovirus vectors containing the lacZ gene or a human alpha 1-antitrypsin (alpha 1AT) cDNA. After in vitro infection with the lacZ adenovirus vector, cultured endothelial cells expressed beta-galactosidase. In parallel studies with the alpha 1AT adenovirus vector, infected cells expressed human alpha 1AT transcripts, as evidenced by in situ hybridization and Northern analysis, and de novo synthesized and secreted glycosylated, functional alpha 1AT within 6 hr of infection, as shown by [35S]methionine labeling and immunoprecipitation. Quantification of the culture supernatants demonstrated 0.3-0.6 micrograms of human alpha 1AT secreted per 10(6) cells in 24 hr, for at least 14 days after adenovirus vector infection. To demonstrate the feasibility of direct transfer of genes into endothelial cells in human blood vessels, lacZ or alpha 1AT adenovirus vectors were placed in the lumen of intact human umbilical veins ex vivo. Histologic evaluation of the veins after 24 hr demonstrated transfer and expression of the lacZ gene specifically to the endothelium. alpha 1AT adenovirus infection resulted both in expression of alpha 1AT transcripts in the endothelium and in de novo synthesis and secretion of alpha 1AT. Quantification of alpha 1AT in the vein perfusates showed average levels of 13 micrograms/ml after 24 hr. These observations strongly support the feasibility of in vivo human gene transfer to the endothelium mediated by replication-deficient adenovirus vectors.

Adenoviruses, Human↗
PubMed1992

Expression of the human cystic fibrosis transmembrane conductance regulator gene in the mouse lung after in vivo intratracheal plasmid-mediated gene transfer.

As an approach to gene therapy for the respiratory manifestations of cystic fibrosis (CF), in vivo plasmid-mediated direct transfer of the normal CF transmembrane conductance regulator (CFTR) gene to the airway epithelium was investigated in mice. To evaluate the feasibility of this strategy, pRSVL, a plasmid composed of a firefly luciferase gene driven by the Rous sarcoma virus long terminal repeat (RSV-LTR), along with cationic liposomes was instilled into the trachea of C57BI/6NCR mice. With administration of 200-400 micrograms plasmid DNA, luciferase expression could be detected in the mouse lung homogenates for at least 4 wk. With this background, a CFTR expression plasmid vector (pRSVCFTR) constructed by replacing the luciferase cDNA from pRSVL with the normal human CFTR cDNA was evaluated in vivo in mice. Intratracheal instillation of pRSVCFTR with cationic liposomes followed by analysis of mouse lung RNA by polymerase chain reaction amplification (after conversion of mRNA to cDNA) using a RSV-LTR specific sense primer and a human CFTR-specific antisense primer demonstrated human CFTR mRNA transcripts from one day to 4 wk after instillation. Further, in vivo evaluation of beta-galactosidase activity after intratracheal administration of an E. coli lacZ gene expression plasmid vector directed by the cytomegalovirus promoter (pCMV beta) demonstrated that the airway epithelium was the major target of transfer and expression of the exogenous gene. These observations demonstrate successful plasmid-mediated gene transfer to the airway epithelium in vivo. This strategy may be feasible as a form of gene therapy to prevent the pulmonary manifestations of CF.

Animals↗
PubMed1992

Gene therapy strategies for pulmonary disease.

The two most common hereditary lung disorders in Caucasians, alpha 1-antitrypsin (alpha 1-AT) deficiency and cystic fibrosis, have their major clinical manifestations in the lung. Rapid advances in biotechnology have resulted in a variety of gene therapy strategies for the potential treatment of these disorders. Three vector systems--plasmid, retrovirus, and adenovirus--have been evaluated for their possible utility in transferring genes in a fashion that would either alter the milieu of the lung or directly alter the genetic program of lung parenchymal cells. Two general strategies can be used: ex vivo modification of autologous cells with subsequent transplantation to the patient and in vivo modification with an appropriate vector containing the exogenous gene. Studies carried out in experimental animals show that it is theoretically possible to treat both alpha 1-AT deficiency and cystic fibrosis with gene therapy if the safety hurdles can be overcome to minimize the risks involved.

Adenoviridae↗
PubMed1992

Transcriptional and posttranscriptional modulation of human neutrophil elastase gene expression.

Human neutrophil elastase (NE), a 29-Kd potent serine protease stored in azurophilic granules of mature neutrophils, is coded for by the NE gene, a single copy gene with 5 exons spanning a 6-kb segment of chromosome 11 at q14. With the knowledge that the NE gene expression is limited to early myeloid cell differentiation, mechanisms modulating expression of the NE gene were evaluated in the HL-60 promyelocytic leukemia cell line, a model of early bone marrow precursor cells. Consistent with the presence of NE messenger RNA (mRNA) transcripts in undifferentiated HL-60 cells, nuclear transcription run-on analyses showed that HL-60 cells actively transcribed the NE gene. However, the transcription rate of the NE gene was relatively low, only 40% of the myeloperoxidase gene, a gene expressed in parallel with NE. When induced toward the mononuclear phagocytic lineage with phorbol 12-myristate 13-acetate (PMA), HL-60 cells exhibited marked suppression of NE gene transcription, declining to 17% of the resting rate within 2 days. Induction toward mononuclear phagocytic lineage differentiation caused no change in NE mRNA transcript half-life (T1/2), but mRNA levels decreased markedly over time, with levels undetectable 1.5 days after PMA stimulation. In contrast, when induced toward the myelocytic lineage with dimethyl sulfoxide, the rate of NE gene transcription increased 1.9-fold within 5 days. Interestingly, the mRNA transcript levels increased 2.5-fold by 5 days despite the fact that induction toward myelocytic lineage differentiation was accompanied by a marked reduction of NE mRNA transcript T1/2. Together, these observations suggest that the NE gene expression during bone marrow differentiation is modulated mainly at the transcriptional level, with some posttranscriptional modulation contributing, particularly during myelocytic lineage differentiation.

Blotting, Northern↗
PubMed1992

Endothelial fenestration of the alveolar capillaries in interstitial fibrotic lung diseases.

A light and electron microscopy study was performed on endothelial cells of alveolar capillaries in biopsied lung tissues obtained from 28 patients with interstitial fibrotic lung diseases, including idiopathic pulmonary fibrosis, sarcoidosis, hypersensitivity pneumonitis, chronic eosinophilic pneumonia, collagen vascular diseases and acute interstitial pneumonia. In the relatively early stages of acute interstitial pneumonia, hypersensitivity pneumonitis and other diseases, the cytoplasms of the endothelial cells appeared swollen and electron-lucent and occasionally showed degeneration and necrosis. Although mitosis was not evident in the endothelium at any disease stage, some capillary endothelial cells showed regeneration. Furthermore, although rarely, they showed obvious phenotypic transformation into diaphragmed fenestrae in some limited segments of fibrotic lungs in the 20 of the 28 patients examined. The frequency of endothelial fenestration seemed to be correlated with the degree of interstitial fibrosis along the alveolar walls. In such fibrotic lung tissues, cuboidal metaplastic cells of bronchiolar origin proliferated on the luminal side. The mechanism of endothelial fenestration in the alveolar capillaries is assumed to be comparable with cuboidal metaplasia of alveolar epithelial cells. The alveolar capillary endothelium is recruited from the bronchiolar capillaries via bronchopulmonary anastomoses unless endothelial repair occurs in situ. Regenerating endothelial cells move into the alveolar capillary tubes along the remnant sleeves of the basement membrane. New endothelial processes finally display their original fenestrated structure while secreting irregular fragments of basement membrane during implantation in the capillary beds.

Adult↗
PubMed1992

Down-regulation of cystic fibrosis transmembrane conductance regulator gene expression by agents that modulate intracellular divalent cations.

In cystic fibrosis (CF), epithelial cells are unable to normally up-regulate apical membrane Cl- secretion in response to agents which increase cyclic AMP, but they do increase Cl- secretion in response to increases in intracellular Ca2+. Since intracellular divalent cations regulate the expression of many genes, we hypothesized that mobilization of intracellular Ca2+ and/or other divalent cations might modulate not only Ca(2+)-dependent Cl- channels but also cystic fibrosis transmembrane conductance regulator (CFTR) gene expression. To evaluate this concept, HT-29 human colon carcinoma cells were cultured under various conditions designed to manipulate intracellular divalent cation concentrations and CFTR gene expression was quantified at the levels of transcription, mRNA accumulation, mRNA half-life, and protein. Exposure to the divalent cation ionophores A23187 and ionomycin (agents which increase intracellular divalent cation concentrations) caused dose- and time-dependent reductions of CFTR mRNA levels, which could be blocked by the use of Ca(2+)- and Mg(2+)-free media. Ionophore-induced CFTR gene modulation was also observed with T84 human colon carcinoma cells and freshly isolated normal human bronchial epithelial cells. Incubation of HT-29 cells with thapsigargin, an agent that releases Ca2+ from intracellular stores, or in medium containing increased extracellular concentrations of Ca2+ or Mg2+ also caused down-regulation of CFTR mRNA levels. Transcription run-on analysis showed that, parallel with the decrease in CFTR mRNA levels, A23187 reduced the rate of transcription of the CFTR gene, while CFTR mRNA transcript half-life was unaffected. Consistent with the down-regulation of CFTR gene expression, CFTR protein levels also decreased after exposure to A23187. Thus, despite the independence of Ca(2+)-dependent Cl- channels and cyclic AMP-dependent CFTR-related Cl- channels in epithelial cells, increases in intracellular divalent cation concentrations down-regulate the expression of the CFTR gene at the transcriptional level, with consequent decreases in CFTR mRNA and protein.

Calcimycin↗
PubMed1992

Intravenous recombinant secretory leukoprotease inhibitor augments antineutrophil elastase defense.

Secretory leukoprotease inhibitor (SLPI), a 12-kDa serine antiprotease, normally protects the upper airway epithelial surface from attack by neutrophil elastase (NE). In the context that a variety of inflammatory lung diseases are characterized by large neutrophil burdens with resultant high levels of NE in the lung, recombinant SLPI (rSLPI), a molecule identical to natural SLPI, may be an effective means to augment the anti-NE protective screen of the lung. To determine whether intravenous rSLPI will augment respiratory tract and epithelial surface levels of SLPI and anti-NE capacity, rSLPI was administered intravenously to sheep and SLPI levels were quantified in plasma, lung lymph (as a measure of lung interstitial levels), lung epithelial lining fluid (ELF), and urine. rSLPI (1 g) was administered over 10 min, and after 30 min plasma levels of SLPI were 8 microM and decreased with a half-life of 1.8 h. Lymph SLPI levels paralleled the plasma levels: 4 h after infusion the lymph-to-plasma ratio was 0.8. ELF SLPI levels paralleled the lymph levels: 4 h after infusion the ELF-to-lymph ratio was 0.3. Western analysis demonstrated intact SLPI in lymph and ELF, and functional analysis showed increases in lymph and ELF anti-NE capacity that paralleled the levels of SLPI. As might be expected from a protein with a molecular mass of 12 kDa, urine excretion was high, with 20% of the SLPI excreted over 5 h. However, if the rate of infusion was slowed, SLPI excretion decreased significantly, with a 3-h infusion associated with 9% excretion and a 12-h infusion associated with less than 0.2% excretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

T-lymphocytes that accumulate in the lung in sarcoidosis have evidence of recent stimulation of the T-cell antigen receptor.

Sarcoidosis, a granulomatous disease of unknown etiology, is characterized at sites of disease such as the lung by the accumulation of large numbers of T-lymphocytes. To differentiate whether the T-cells accumulate in organs nonspecifically (e.g., through chemotaxis or tumorlike proliferation) or more specifically through an antigen-driven ordered immune response, the present study capitalized on the knowledge that specific antigen stimulation of T-cells requires antigen interactions with the T-cell antigen receptor (TCR), resulting in a decrease in the number of surface TCR and a concomitant increase in TCR mRNA levels, i.e., if lung T-cell accumulation in pulmonary sarcoid results from an ordered immune response, lung, but not blood, T-cells should demonstrate evidence of recent triggering of the alpha beta receptor, the most abundant type of TCR. The surface density of T-cell surface alpha beta TCR expression was evaluated by flow cytometry with an anti-alpha beta antibody and TCR beta-chain mRNA transcript number quantified by in situ hybridization with 35S-labeled antisense and sense cRNA probes. Control studies utilizing normal blood T-lymphocytes stimulated with the anti-CD3 monoclonal antibody, OKT3, in the presence of autologous monocytes, demonstrated the expected down-regulation of surface alpha beta TCR expression and increased beta-chain mRNA transcript number. When lung and blood T-cells of patients with pulmonary sarcoidosis were compared immediately upon recovery (i.e., without in vitro stimulation), the lung T-cells of 10 of 10 subjects demonstrated a decreased surface density of alpha beta TCR compared with their autologous blood T-cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Neutrophil elastase in respiratory epithelial lining fluid of individuals with cystic fibrosis induces interleukin-8 gene expression in a human bronchial epithelial cell line.

The respiratory manifestations of cystic fibrosis (CF) are characterized by neutrophil-dominated airway inflammation. Since a variety of inflammatory stimuli are capable of inducing bronchial epithelial cells to express the gene for IL-8, a cytokine that attracts and activates neutrophils, mediators in respiratory epithelial lining fluid (ELF) of CF individuals might induce IL-8 production by epithelial cells, thus recruiting neutrophils to the airways. BET-1A human bronchial epithelial cells at rest or incubated with normal ELF showed little IL-8 gene expression, but after incubation with CF ELF, a marked increase in IL-8 transcript levels was observed. CF ELF contained high levels of neutrophil elastase (NE) and various serine protease inhibitors prevented CF ELF from inducing IL-8 gene expression in BET-1A cells, suggesting that NE was the dominant inducer for IL-8 production in CF ELF. The addition of purified NE caused BET-1A cells to increase IL-8 gene transcription with accumulation of mRNA transcripts and to release IL-8-like neutrophil chemotactic activity. These observations suggest a self-perpetuating inflammatory process on the CF bronchial surface where NE released by neutrophils induced the bronchial epithelium to secrete IL-8, which in turn recruits additional neutrophils to the bronchial surface.

Base Sequence↗