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Biomedical subjects

Roland M du Bois

Publications and source records attributed to Roland M du Bois.

At least 19 recordsLinked to original sources
PubMed2007

TNF polymorphism and bronchoalveolar lavage cell TNF-alpha levels in chronic beryllium disease and beryllium sensitization.

BACKGROUND: Beryllium stimulates TNF-alpha from chronic beryllium disease (CBD) bronchoalveolar lavage (BAL) cells. OBJECTIVE: We sought to relate TNF polymorphisms to beryllium-stimulated TNF-alpha production, to the development of CBD, and to the risk of more severe CBD over time. METHODS: We recruited 147 patients with CBD, 112 beryllium-sensitized subjects, and 323 control subjects; genotyped 5 TNF promoter polymorphisms; and measured beryllium-stimulated and unstimulated BAL cell TNF-alpha production from a subset of subjects. RESULTS: Beryllium-stimulated, but not beryllium-unstimulated, BAL cell TNF-alpha production was significantly increased in patients with CBD compared with that seen in those only sensitized (P = .0002). Those subjects with the TNF -857T allele and the only haplotype (haplotype 4) containing this allele demonstrated significantly lower unstimulated BAL cell TNF-alpha production compared with that seen in noncarriers (P = .009). Patients with CBD alone and combined with sensitized subjects carrying the TNF haplotype 1 compared with those without this haplotype had significantly increased beryllium-stimulated BAL cell TNF-alpha levels (P = .02). We found no significant association between patients with CBD, sensitized subjects, and control subjects with any of the TNF promoter polymorphisms or haplotypes. A greater decrease in Pao(2) at maximum exercise was noted in patients with CBD with the -1031C allele (P = .03) and with haplotypes other than the TNF haplotype 1 (P = .01), 3 (from 5) of which contain the -1031C allele. CONCLUSIONS: The -857T allele and haplotype 1 are associated with BAL cell TNF-alpha production, indicating a potential role of TNF promoter variants in regulation of TNF production in sensitized subjects and patients with CBD. CLINICAL IMPLICATIONS: TNF promoter variants are not risk factors for CBD or sensitization.

Adult↗
PubMed2006

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia: an under-recognised spectrum of disease.

AIMS AND METHODS: A review was undertaken of 19 patients diagnosed with diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) between 1992 and 2006. RESULTS: Most patients were women (n = 15) and non-smokers (n = 16). Clinical presentation was either with symptomatic pulmonary disease (group 1; n = 9) or as an incidental finding during investigation for another disorder, most frequently malignant disease (group 2; n = 10). In group 1, cough and dyspnoea were the most frequent symptoms, with an average duration of 8.6 years before diagnosis. Both groups showed mainly stable disease without treatment, although one patient progressed to severe airflow obstruction and one was diagnosed at single lung transplantation. Mosaicism with nodule(s) was the typical pattern of DIPNECH on high-resolution computed tomography, but one case had normal imaging despite airflow obstruction. Lung function tests showed obstructive (n = 8), mixed (n = 3) or normal (n = 5, all group 2) physiology. Two patients underwent a bronchoalveolar lavage and showed a lymphocytosis (30%) with mild chronic bronchiolitis being seen in all biopsies. Tumourlets and associated typical carcinoids (n = 9) showed weak positivity for thyroid transcription factor-1. Three patients had atypical carcinoids, one with multiple endocrine neoplasia type 1 syndrome. CONCLUSIONS: DIPNECH is being increasingly recognised, probably because of an increase in the usage and accuracy of investigative imaging and increased awareness of the entity. Most cases remain stable over many years independent of the mode of presentation, although a few patients progress to severe airflow obstruction.

Adult↗
PubMed2006

Acute exacerbation of interstitial pneumonia following surgical lung biopsy.

STUDY OBJECTIVES: Surgical lung biopsy (SLB) plays an important role in the diagnosis of interstitial pneumonia, however, the occurrence of acute respiratory failure following SLB remains largely unreported. We evaluated the incidence, clinical features, therapy and prognosis of acute exacerbation of interstitial pneumonia following SLB. DESIGN: Retrospective study of consecutive patients who underwent SLB to establish a diagnosis of diffuse lung disease between May 1989 and April 2000. Patients with an acute exacerbation following lung biopsy were studied, and the HRCT images of the chest before and after surgery were reviewed. MEASUREMENTS AND RESULTS: Among the 236 consecutive patients with interstitial pneumonia who underwent a surgical lung biopsy, five (2.1%) (IPF, 3; NSIP, 1; COP, 1) developed acute exacerbation of the diffuse lung disease in the course of 1-18 days after SLB. The extent of parenchymal involvement on HRCT before surgery was not significantly different between operated and contralateral nonoperated lung. Significantly increased regions of parenchymal involvement on HRCT were seen postoperatively compared with the preoperative CT in both the operated (20.7+/-12.5% versus 38.2+/-10.8%, P = 0.0431) and nonoperated lung (22.7+/-13.8% versus 70.5+/-24.4%, P = 0.0431), but the extent of the parenchymal involvement was significantly greater on the nonoperated side (P = 0.0251). Two of the 3 IPF patients died from the acute exacerbation. CONCLUSIONS: It is important to be aware of the possibility of acute exacerbation of interstitial pneumonia following SLB even after an apparently uneventful immediate postoperative course. The asymmetric image findings suggest that intraoperative respiratory management is a possible etiologic factor.

Acute Disease↗
PubMed2006

Chymase gene (CMA1) polymorphisms in Dutch and Japanese sarcoidosis patients.

BACKGROUND: Chymase is released from mast cells following activation. Evidence suggests that chymase plays an important role in tissue injury and remodeling of the lungs, heart and skin. OBJECTIVE: We postulated that chymase gene (CMA1) polymorphisms are associated with pulmonary fibrosis in Dutch and with cardiac and skin involvement in Japanese sarcoidosis patients. PATIENTS AND METHODS: Dutch (n = 153) and Japanese (n = 122) sarcoidosis patients with controls (Dutch, n = 309; Japanese, n = 111) were studied. Pulmonary involvement in Dutch patients as well as clinical manifestations in Japanese patients was evaluated for association with five CMA1 polymorphisms. RESULTS: The CMA1 polymorphisms were not associated with disease susceptibility in either population, or with radiographic evolution in the Dutch or with cardiac or skin involvement in the Japanese patients. The -526 T allele was associated with a lower iVC in Dutch patients. CONCLUSIONS: The CMA1 polymorphisms studied do not contribute to disease susceptibility in Japanese or Dutch sarcoidosis patients. CMA1 polymorphisms do not influence radiographic evolution in Dutch sarcoidosis patients, nor do they predispose to cardiac or skin involvement in Japanese patients. However, the association between CMA1 -526 C/T and iVC in the Dutch patients suggests that chymase may modify the functional outcome of pulmonary sarcoidosis.

3' Untranslated Regions↗
PubMed2006

Protein profiles of bronchoalveolar lavage fluid from patients with pulmonary sarcoidosis.

BACKGROUND: Pulmonary sarcoidosis is a multisystem granulomatous disease with various clinical phenotypes. So far, there has been little information on protein patterns (PPs) of bronchoalveolar lavage fluid (BALF) from patients with sarcoidosis and no data are available on PPs in clinical disease subtypes. OBJECTIVES: To investigate the PP of BALF from patients with pulmonary sarcoidosis, to evaluate whether PPs reflect disease course as assessed by chest X-ray (CXR), and to compare PPs between patients with/without Löfgren's syndrome. METHODS: Surface-enhanced laser desorption/ionization-time-of-flight mass spectroscopy was applied to investigate PPs in unconcentrated BALF from 65 patients (CXR stage I, n = 32; CXR stage II, n = 22, CXR stage III, n = 11) and 23 healthy control subjects. The Mann-Whitney U test was used to detect differentially expressed protein peaks. After reversed-phase fractionation, peptide fingerprint mapping and immunodepletion were used to identify deregulated (up-regulated or down-regulated) proteins. RESULTS: Forty differentially expressed protein entities (2.75-185.62 kD) were detected in patients with pulmonary sarcoidosis versus control subjects (p < 0.05). Whereas 13 peaks (33%) were present across all CXR stages, 27 (67%) were specific for particular CXR stages. Comparison of PPs between CXR stage I patients with or without Löfgren's syndrome revealed 25 differentially expressed peaks. The total number of deregulated peaks and also of those associated with sarcoidosis as a whole were markedly lower in patients with Löfgren's syndrome in comparison with other sarcoid phenotypes. Human serum albumin, alpha1-antitrypsin, and protocadherin-2 precursor were identified from sarcoidosis-associated PP. CONCLUSION: Surface-enhanced laser desorption/ionization-time-of-flight mass spectroscopy enables determination of protein patterns in sarcoid BALF and allows detection of protein patterns linked to a particular disease course.

Adult↗
PubMed2006

A multicenter, prospective, randomized, double-blind, placebo-controlled trial of corticosteroids and intravenous cyclophosphamide followed by oral azathioprine for the treatment of pulmonary fibrosis in scleroderma.

OBJECTIVE: The lack of randomized controlled trials (RCTs) in pulmonary fibrosis in systemic sclerosis (SSc) has hampered an evidence-based approach to treatment. This RCT was undertaken to investigate the effects of intravenous (IV) cyclophosphamide (CYC) followed by azathioprine (AZA) treatment in pulmonary fibrosis in SSc. METHODS: Forty-five patients were randomized to receive low-dose prednisolone and 6 infusions (monthly) of CYC followed by oral AZA, or placebo. Primary outcome measures were change in percent predicted forced vital capacity (FVC) and change in single-breath diffusing capacity for carbon monoxide (DLCO). Secondary outcome measures included changes in appearance on high-resolution computed tomography and dyspnea scores. An intent-to-treat statistical analysis was performed. RESULTS: At baseline, there were no significant group differences in factors linked to outcome, including severity of pulmonary fibrosis and autoantibody status. Sixty-two percent of the patients completed the first year of treatment. Withdrawals included 9 patients (6 from the placebo group) with significant decline in lung function, 2 with treatment side effects (both from the active treatment group), and 6 with non-trial-related comorbidity. No hemorrhagic cystitis or bone marrow suppression was observed. Estimation of the relative treatment effect (active treatment versus placebo) adjusted for baseline FVC and treatment center revealed a favorable outcome for FVC of 4.19%; this between-group difference showed a trend toward statistical significance (P = 0.08). No improvements in DLCO or secondary outcome measures were identified. CONCLUSION: This trial did not demonstrate significant improvement in the primary or secondary end points in the active treatment group versus the group receiving placebo. However, for FVC there was a trend toward statistical significance between the 2 groups. This suggests that treatment of pulmonary fibrosis in SSc with low-dose prednisolone and IV CYC followed by AZA stabilizes lung function in a subset of patients with the disease. Therapy was well tolerated with no increase in serious adverse events.

Administration, Oral↗
PubMed2006

Evolving concepts in the early and accurate diagnosis of idiopathic pulmonary fibrosis.

The diagnosis of idiopathic pulmonary fibrosis (IPF) requires an integrated multidisciplinary approach involving pulmonologists, radiologists, and pathologists. Early recognition of IPF and of its differentiation from other interstitial lung diseases is important for directing patient management and predicting prognosis. Clinical suspicion of IPF should be raised when patients, particularly those over 50 years of age, present with dyspnea that is gradual in onset and progressive. A confident diagnosis of IPF can be made based on clinical assessment, pulmonary function test results, and radiographic and bronchoscopic evaluation. However, the definitive diagnosis of IPF requires a surgical lung biopsy to confirm the histopathologic pattern of usual interstitial pneumonia.

Diagnosis, Differential↗
PubMed2006

Genetic factors in pulmonary fibrotic disorders.

Identifying genetic determinants of pulmonary fibrotic disorders remains at an early stage of evolution. It is now well-recognized that "pulmonary fibrosis" covers a broad range of lung diseases, including most topically the idiopathic interstitial pneumonias that have been classified recently. Additionally, it is recognized that the fibrosing lung disorders that are seen in the rheumatological diseases, notably systemic sclerosis, are quite different from those of the idiopathic variety. Defining clinical phenotype is an important prerequisite to the identification of genetic determinants associated with individual diseases, but it is important to acknowledge that there may be determinants of global lung fibrosis and that other factors drive diseases down specific, more individual disease pathways. Current association studies are encouraging but far from conclusive for a variety of reasons, including small numbers, poor controls, and curious candidate selection. The results of the ongoing multicenter familial linkage study in the United States should provide several candidate genes that will spur further studies of sporadic disease in, it is hoped, a more internationally coordinated effort.

Genetic Predisposition to Disease↗
PubMed2006

Natural history of hepatic sarcoidosis and its response to treatment.

BACKGROUND: Liver involvement in sarcoidosis is variable and can occur in the absence of pulmonary disease. Data on the natural history of hepatic sarcoid and response to therapy are lacking. This study investigates hepatic dysfunction complicating lung disease and significant liver involvement presenting independent of pulmonary sarcoid. PATIENTS AND METHODS: One hundred and eighty patients were included in the study. The minimum follow-up was 2 years. RESULTS: Fifty per cent of the study population had derangement of liver function attributable to hepatic sarcoid. Twenty-three patients (13%) had liver involvement without lung disease. Sixty-three patients were administered corticosteroids; approximately one-third had a complete clinical response, one-third a partial response and one-third showed no response. Fourteen patients (8%) were cirrhotic at presentation, and two progressed to cirrhosis despite steroid therapy. Sixteen patients received a second-line immunosuppressive agent; one-half of these showed a response to treatment augmentation (four patients azathioprine, three patients methotrexate, one patient both drugs). Six patients required liver transplantation, with disease recurrence in one recipient. In four patients, sarcoid as the aetiology of end-stage liver disease was diagnosed only on examination of the explanted liver. CONCLUSION: Sarcoidosis can cause end-stage chronic liver disease, which is often unrecognized until examination of the explanted liver. Response to conventional immunosuppression is variable and unpredictable. Transplantation is feasible and safe in this population but recurrence is possible.

Adult↗
PubMed2006

Constitutive ALK5-independent c-Jun N-terminal kinase activation contributes to endothelin-1 overexpression in pulmonary fibrosis: evidence of an autocrine endothelin loop operating through the endothelin A and B receptors.

The signal transduction mechanisms generating pathological fibrosis are almost wholly unknown. Endothelin-1 (ET-1), which is up-regulated during tissue repair and fibrosis, induces lung fibroblasts to produce and contract extracellular matrix. Lung fibroblasts isolated from scleroderma patients with chronic pulmonary fibrosis produce elevated levels of ET-1, which contribute to the persistent fibrotic phenotype of these cells. Transforming growth factor beta (TGF-beta) induces fibroblasts to produce and contract matrix. In this report, we show that TGF-beta induces ET-1 in normal and fibrotic lung fibroblasts in a Smad-independent ALK5/c-Jun N-terminal kinase (JNK)/Ap-1-dependent fashion. ET-1 induces JNK through TAK1. Fibrotic lung fibroblasts display constitutive JNK activation, which was reduced by the dual ETA/ETB receptor inhibitor, bosentan, providing evidence of an autocrine endothelin loop. Thus, ET-1 and TGF-beta are likely to cooperate in the pathogenesis of pulmonary fibrosis. As elevated JNK activation in fibrotic lung fibroblasts contributes to the persistence of the myofibroblast phenotype in pulmonary fibrosis by promoting an autocrine ET-1 loop, targeting the ETA and ETB receptors or constitutive JNK activation by fibrotic lung fibroblasts is likely to be of benefit in combating chronic pulmonary fibrosis.

Actins↗
PubMed2005

C-C chemokine receptor 5 gene variants in relation to lung disease in sarcoidosis.

RATIONALE: Genetic factors are likely to influence the clinical course and pattern of sarcoidosis, a granulomatous disease of unknown origin. OBJECTIVES: We tested this hypothesis for C-C chemokine receptor 5 (CCR5), a molecule involved in recruitment and activation of mononuclear cells. METHODS: In addition to the known CCR5 Delta 32 insertion/deletion, we evaluated a further eight single-nucleotide polymorphisms in 106 British patients and 142 British unaffected subjects, and second-setted the results in 112 Dutch patients and 169 healthy Dutch control subjects. MEASUREMENTS AND MAIN RESULTS: In the British population, the frequency of one of the identified haplotypes (HHC) was strongly associated with the presence of parenchymal disease (radiographic stage >or= II versus stages 0 and I) at presentation (odds ratio [OR], 5.2; 95% confidence interval [CI], 1.96-13.7; corrected p = 0.02), at 2 (OR, 6.6; 95% CI, 2.5-17.6; corrected p = 0.006), and at 4 years follow-up (OR, 6.8; 95% CI, 2.5-18.0; corrected p = 0.0045). In the Dutch population, the same association was seen at 2 (OR, 6.7; 95% CI, 2.8-16.4; corrected p = 0.002), and 4 years follow-up (OR, 9.0; 95% CI, 3.5-23.1; corrected p = 0.0009). CONCLUSIONS: No association between the CCR5 haplotype HHC and susceptibility to sarcoidosis was observed, indicating that this relevant gene only operates after disease induction. In summary, we report a strong association between CCR5 haplotype HHC and persistent lung involvement in sarcoidosis.

Case-Control Studies↗
PubMed2005

Induction of epithelial-mesenchymal transition in alveolar epithelial cells by transforming growth factor-beta1: potential role in idiopathic pulmonary fibrosis.

The hallmark of idiopathic pulmonary fibrosis (IPF) is the myofibroblast, the cellular origin of which in the lung is unknown. We hypothesized that alveolar epithelial cells (AECs) may serve as a source of myofibroblasts through epithelial-mesenchymal transition (EMT). Effects of chronic exposure to transforming growth factor (TGF)-beta1 on the phenotype of isolated rat AECs in primary culture and a rat type II cell line (RLE-6TN) were evaluated. Additionally, tissue samples from patients with IPF were evaluated for cells co-expressing epithelial (thyroid transcription factor (TTF)-1 and pro-surfactant protein-B (pro-SP-B), and mesenchymal (alpha-smooth muscle actin (alpha-SMA)) markers. RLE-6TN cells exposed to TGF-beta1 for 6 days demonstrated increased expression of mesenchymal cell markers and a fibroblast-like morphology, an effect augmented by tumor necrosis factor-alpha (TNF-alpha). Exposure of rat AECs to TGF-beta1 (100 pmol/L) resulted in increased expression of alpha-SMA, type I collagen, vimentin, and desmin, with concurrent transition to a fibroblast-like morphology and decreased expression of TTF-1, aquaporin-5 (AQP5), zonula occludens-1 (ZO-1), and cytokeratins. Cells co-expressing epithelial markers and alpha-SMA were abundant in lung tissue from IPF patients. These results suggest that AECs undergo EMT when chronically exposed to TGF-beta1, raising the possibility that epithelial cells may serve as a novel source of myofibroblasts in IPF.

Actins↗
PubMed2005

TNF-857T, a genetic risk marker for acute anterior uveitis.

PURPOSE: To determine the association between 17 single nucleotide polymorphisms (SNPs) of tumor necrosis factor-alpha, lymphotoxin-alpha, and the TNF-receptors genes (TNF, LTA, and TNFRSF1A and -B) and idiopathic acute anterior uveitis (IAU) and to investigate their association with HLA-B27 and/or the development of visually significant complications. METHODS: Ninety-eight white patients in the United Kingdom were identified (by SL) from the uveitis clinics of Moorfields Eye Hospital (London, UK). Sequence-specific primers with 3' end mismatches were used to identify the presence of specific allelic variants by PCR amplification. RESULTS: There was a significant increase in the frequency of the TNF-857T allele in patients with IAU when compared with control subjects (15.3% vs. 7.3%, P = 0.0006). The frequency of haplotype 4, containing the T allele at nucleotide position -857, was also significantly increased in patients with IAU compared with control subjects (15.4% vs. 7.1%, P = 0.0003, OR 2.4, 95% confidence interval 1.4-4.0). In subgroup analysis, there were significant differences in the frequencies of the uncommon TNFRSF1A-201T and TNFRSF1A-1135T alleles between HLA-B27(+) patients with inflammation-related complications and those without complications (80.0% vs. 33.6%, P = 0.006; 80.0% vs. 36.6%, P = 0.01, respectively). CONCLUSIONS: A significant difference in the frequency of TNF-857T allele was found in patients with IAU. There was a trend toward the development of inflammation-related complications in HLA-B27(+) patients with IAU who were carriers of TNFRSF1A-201T or TNFRSF1A-1135T alleles. Genetic variations in these proinflammatory mediators and their receptors appear to influence the susceptibility and severity of the inflammatory response within the eyes of patients during the development of IAU.

Acute Disease↗
PubMed2005

Analysis of KL-6 and SP-D as disease markers in bird fancier's lung.

BACKGROUND AND AIM: KL-6 and SP-D are potential serum markers in interstitial lung diseases. Their discriminative value, and ability to reflect pulmonary disease activity and prognosis in bird fancier's lung were analyzed. METHODS: We studied 49 patients, 38 unexposed and 9 exposed controls. Serum KL-6 and SP-D concentrations were measured at presentation and a second sample, taken after antigen avoidance, was available in 17 patients. Pulmonary function tests were analyzed at presentation and 2-year follow-up. RESULTS: KL-6 and SP-D were significantly elevated in patients compared to controls (p < 0.0001). ROC curve analysis revealed that both are equally useful in discriminating patients from controls. Analysis of their value as activity markers showed that both correlated with pulmonary function impairment; however, KL-6 correlated best with diffusing capacity. Evaluation of their predictive value showed that higher levels at onset were associated with improvement of diffusing capacity during follow-up. Further, it was noted that KL-6 and SP-D levels decreased after more than one month of allergen avoidance. CONCLUSIONS: KL-6 and SP-D appear useful serum markers in bird fancier's lung. Since higher levels are associated with more severe lung function impairment at presentation, and better recovery over time, we postulate that in this disease they are especially markers of disease activity.

Antigens↗
PubMed2004

Gene expression profiling reveals novel TGFbeta targets in adult lung fibroblasts.

BACKGROUND: Transforming growth factor beta (TGFbeta), a multifunctional cytokine, plays a crucial role in the accumulation of extracellular matrix components in lung fibrosis, where lung fibroblasts are considered to play a major role. Even though the effects of TGFbeta on the gene expression of several proteins have been investigated in several lung fibroblast cell lines, the global pattern of response to this cytokine in adult lung fibroblasts is still unknown. METHODS: We used Affymetrix oligonucleotide microarrays U95v2, containing approximately 12,000 human genes, to study the transcriptional profile in response to a four hour treatment with TGFbeta in control lung fibroblasts and in fibroblasts from patients with idiopathic and scleroderma-associated pulmonary fibrosis. A combination of the Affymetrix change algorithm (Microarray Suite 5) and of analysis of variance models was used to identify TGFbeta-regulated genes. Additional criteria were an average up- or down- regulation of at least two fold. RESULTS: Exposure of fibroblasts to TGFbeta had a profound impact on gene expression, resulting in regulation of 129 transcripts. We focused on genes not previously found to be regulated by TGFbeta in lung fibroblasts or other cell types, including nuclear co-repressor 2, SMAD specific E3 ubiquitin protein ligase 2 (SMURF2), bone morphogenetic protein 4, and angiotensin II receptor type 1 (AGTR1), and confirmed the microarray results by real time-PCR. Western Blotting confirmed induction at the protein level of AGTR1, the most highly induced gene in both control and fibrotic lung fibroblasts among genes encoding for signal transduction molecules. Upregulation of AGTR1 occurred through the MKK1/MKK2 signalling pathway. Immunohistochemical staining showed AGTR1 expression by lung fibroblasts in fibroblastic foci within biopsies of idiopathic pulmonary fibrosis. CONCLUSIONS: This study identifies several novel TGFbeta targets in lung fibroblasts, and confirms with independent methods the induction of angiotensin II receptor type 1, underlining a potential role for angiotensin II receptor 1 antagonism in the treatment of lung fibrosis.

Cells, Cultured↗
PubMed2004

Endothelin-1 promotes myofibroblast induction through the ETA receptor via a rac/phosphoinositide 3-kinase/Akt-dependent pathway and is essential for the enhanced contractile phenotype of fibrotic fibroblasts.

The endothelins are a family of endothelium-derived peptides that possess a variety of functions, including vasoconstriction. Endothelin-1 (ET-1) is up-regulated during tissue repair and promotes myofibroblast contraction and migration, hence contributing to matrix remodeling during tissue repair. Here, we show that addition of ET-1 to normal lung fibroblasts induces expression of proteins that contribute to a contractile phenotype, including alpha-smooth muscle actin (alpha-SMA), ezrin, moesin, and paxillin. We confirm that ET-1 enhances the ability of lung fibroblasts to contract extracellular matrix, a function essential for tissue repair, through induction of de novo protein synthesis. Blockade of the Akt/phosphoinositide 3-kinase (PI3-kinase) pathway with LY294002 and wortmannin prevents the ability of ET-1 to induce alpha-SMA, ezrin, paxillin, and moesin and to promote matrix contraction. Dominant negative rac and Akt blocked the ability of ET-1 to promote formation of alpha-SMA stress fibers. Using specific ET-1 receptor inhibitors, we show that ET-1 induces collagen matrix contraction through the ETA, but not the ETB, receptor. Relative to normal pulmonary fibroblasts, fibroblasts cultured from scars of patients with the fibrotic disease systemic sclerosis (scleroderma) show enhanced ET-1 expression and binding. Systemic sclerosis lung fibroblasts show increased ability to contract a collagen matrix and elevated expression of the procontractile proteins alpha-SMA, ezrin, paxillin, and moesin, which are greatly reduced by antagonizing endogenous ET-1 signaling. Thus, blocking ET-1 or the PI3-kinase/Akt cascades might be beneficial in reducing scar formation in pulmonary fibrosis.

Cell Membrane↗