[Therapy of cystic fibrosis in adulthood--current and future management].
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Adult↗
Biomedical subjects
J Bargon
Publications and source records attributed to J Bargon.
[Mucoviscidosis--3 years after discovery of the gene].
The discovery of the cystic fibrosis (cF) gene was the first step to evaluate the function of its product, the "cystic fibrosis transmembrane conductance regulator" protein and the regulation of this gene. CFTR is a cAMP-dependent CI(-)-channel, which is defect in cF. In contrast, a second CI(-)-channel in epithelial cells is activated by increasing intracellular Ca++ and fully functional in cF cells. Increasing intracellular Ca++ not only activates the Ca(++)-dependent channel, but also downregulates the CFTR gene expression in the same epithelial cells, suggesting a feedback mechanism. This regulatory pathway is based on a protein kinase, probably protein kinase C. The results of this study are a prerequisite for a gene therapy in cF which demands intimate knowledge of the regulation of the CFTR gene. In addition, these results suggest different therapeutical strategies to circumvent the defect in cF cells, which is discussed in detail.
Adenocarcinoma↗
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↗
In vivo transfer of the human cystic fibrosis transmembrane conductance regulator gene to the airway epithelium.
Direct transfer of the normal cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene to airway epithelium was evaluated using a replication-deficient recombinant adenovirus (Ad) vector containing normal human CFTR cDNA (Ad-CFTR). In vitro Ad-CFTR-infected CFPAC-1 CF epithelial cells expressed human CFTR mRNA and protein and demonstrated correction of defective cAMP-mediated Cl- permeability. Two days after in vivo intratracheal introduction of Ad-CFTR in cotton rats, in situ analysis demonstrated human CFTR gene expression in lung epithelium. PCR amplification of reverse transcribed lung RNA demonstrated human CFTR transcripts derived from Ad-CFTR, and Northern analysis of lung RNA revealed human CFTR transcripts for up to 6 weeks. Human CFTR protein was detected in epithelial cells using anti-human CFTR antibody 11-14 days after infection. While the safety and effectiveness remain to be demonstrated, these observations suggest the feasibility of in vivo CFTR gene transfer as therapy for the pulmonary manifestations of CF.
Adenoviruses, Human↗
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↗
Down-regulation of cystic fibrosis gene mRNA transcript levels and induction of the cystic fibrosis chloride secretory phenotype in epithelial cells by phorbol ester.
To evaluate the hypothesis that phorbol myristate acetate (PMA) might modulate the expression of the cystic fibrosis (CF) gene in epithelial cells, we examined the effect of PMA on CF mRNA levels and regulation of Cl- secretion. Strikingly, PMA down-regulated CF mRNA transcript numbers in a dose- and time-dependent manner. Importantly, in parallel with the reduction of CF mRNA levels, PMA-treated cells were unable to up-regulate Cl- secretion in a normal fashion in response to forskolin, an effect which was also dose- and time-dependent. Thus, PMA is capable of modulating expression of the CF gene and induces T84 cells to adopt the "CF phenotype" in regard to regulation of Cl- ion transport.
Blotting, Northern↗
[Salazosulfapyridine-induced eosinophilic pneumonia with pulmonary and cutaneous epithelioid cell granulomatosis in Sjögren syndrome].
A 68-year old woman suffering from Sjögren's syndrome for the last 30 years took sulphasalazine (SSP) for severe signs and symptoms at the joints. Soon after the start of this medication she developed progressive cough and shortness of breath. After two years she was referred for evaluation of a hemoptysis and a reddish skin lesion. The chest radiograph showed wide spread interstitial infiltrates in the lower lobes and some fibrotic changes. FVC was slightly reduced, DLCO markedly reduced. There was a high percentage of eosinophils in the bronchoalveolar lavage (55.2%). Transbronchial lung biopsy and skin biopsy demonstrated epitheloid granulomata. SSP was discontinued. After a short period of prednisone treatment the patient's condition improved considerably. After two months of followup neither pulmonary infiltrates nor any skin lesions were found. History and the clinical course after discontinuation of SSP indicate the relation of these infiltrates to SSP treatment. The previously published case reports of SSP-related lung disorders are reviewed. Three of these case reports included bronchoalveolar lavage. Our data suggest that patients with SSP related pulmonary infiltrates may have a marked increase of eosinophils in the bronchoalveolar lavage fluid.
Aged↗
[Clinical aspects and diagnosis of chronic berylliosis--a case report].
Three case reports of patients with chronic berylliosis are presented. The examination findings of these three cases are all unspecific. Merely the lymphocyte transformation test (LTT), which has, in the meantime, become an established procedure, is capable of demonstrating, at a high level of sensitivity and specificity, the presence of sensitisation towards beryllium, a condition that accompanies the disease itself. All three patients showed a positive LTT. A modification of the diagnostic criteria worked out by Sprince, is proposed, which takes into account the LTT performed in blood and bronchoalveolar fluid.
Adult↗
Lymphocyte transformation test in a group of foundry workers exposed to beryllium and non-exposed controls.
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Adult↗