Regulation of the effects of TGF-beta 1 by activation of latent TGF-beta 1 and differential expression of TGF-beta receptors (Tbeta R-I and Tbeta R-II) in idiopathic pulmonary fibrosis
Notice bibliographique
Résumé
BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is characterised by subpleural fibrosis that progresses to involve all areas of the lung. The expression of transforming growth factor-beta1 (TGF-beta 1), a potent regulator of connective tissue synthesis, is increased in lung sections of patients with IPF. TGF-beta 1 is generally released in a biologically latent form (L-TGF-beta 1). Before being biologically active, TGF-beta must be converted to its active form and interact with both TGF-beta receptors type I and II (T beta R-I and T beta R-II). TGF-beta latency binding protein 1 (LTBP-1), which facilitates the release and activation of L-TGF-beta 1, is also important in the biology of TGF-beta 1. METHODS: Open lung biopsy samples from patients with IPF and normal controls were examined to localise T beta R-I, T beta R-II, and LTBP-1. Alveolar macrophages (AM) and bronchoalveolar lavage (BAL) fluid were examined using the CCL-64 bioassay to determine if TGF-beta is present in its active form in the lungs of patients with IPF. RESULTS: Immunoreactive L-TGF-beta 1 was present in all lung cells of patients with IPF except for fibroblasts in the subepithelial regions of honeycomb cysts. LTBP-1 was detected primarily in AM and epithelial cells lining honeycomb cysts in areas of advanced IPF. In normal lungs LTBP-1 immunoreactivity was observed in a few AM. AM from the upper and lower lobes of patients with IPF secreted 1.6 (0.6) fmol and 4.1 (1.9) fmol active TGF-beta, respectively, while AM from the lower lobes of control patients secreted no active TGF-beta (p< or =0.01 for TGF-beta in the conditioned media from AM obtained from the lower lobes of IPF patients v normal controls). The difference in percentage active TGF-beta secreted by AM from the lower lobes of patients with IPF and the lower lobes of control patients was significant (p< or =0.01), but the difference between the total TGF-beta secreted from these lobes was not significant. The difference in active TGF-beta in conditioned media of AM from the upper and lower lobes of patients with IPF was also not statistically significant. BAL fluid from the upper and lower lobes of patients with IPF contained 0.7 (0.2) fmol and 2.9 (1.2) fmol active TGF-beta, respectively (p< or =0.03). The percentage of active TGF-beta in the upper and lower lobes was 17.6 (1.0)% and 78.4 (1.6)%, respectively (p< or =0.03). In contrast, BAL fluid from control patients contained small amounts of L-TGF-beta. Using immunostaining, both T beta R-I and T beta R-II were present on all cells of normal lungs but T beta R-I was markedly reduced in most cells in areas of honeycomb cysts except for interstitial myofibroblasts in lungs of patients with IPF. TGF-beta 1 inhibits epithelial cell proliferation and a lack of T beta R-I expression by epithelial cells lining honeycomb cysts would facilitate repair of the alveoli by epithelial cell proliferation. However, the presence of both T beta Rs on fibroblasts is likely to result in a response to TGF-beta 1 for synthesis of connective tissue proteins. Our findings show that biologically active TGF-beta 1 is only present in the lungs of patients with IPF. In addition, the effects of TGF-beta 1 on cells may be further regulated by the expression of T beta Rs. CONCLUSION: Activation of L-TGF-beta 1 and the differential expression of T beta Rs may be important in the pathogenesis of remodelling and fibrosis in IPF.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».