Keratinocyte differentiation inversely regulates the expression of involucrin and transforming growth factor β1
Notice bibliographique
Résumé
Extensive skin loss from a variety of conditions such as severe thermal injury is associated with significant functional morbidity and mortality. In recent years, the healing quality has been improved for patients who suffer burns due in part to the usage of skin replacement mainly prepared from multi-layered sheets of cultured keratinocytes. Although it is known that keratinocytes are a rich source of wound healing promoting factors such as transforming growth factor-beta1 (TGF-beta1), it is not clear whether differentiated keratinocytes in a multi-layer form release this multi-functional growth factor and has any functional influence on dermal fibroblasts. This study examined the hypothesis that keratinocytes in mono- and multi-layer forms express different levels of TGF-beta1. To address this hypothesis, keratinocytes were grown in serum free medium (KSFM) supplemented with bovine pituitary extract (50 microg/ml) and EGF (5 microg/ml). When cells reached confluency, conditioned medium was removed and replaced with 50% KSFM with no additives and 50% DMEM without serum and cells were allowed to form multi-layers and differentiate. The conditioned medium was then collected every 48 h up to 24 days and the level of TGF-beta1 and the efficacy of a keratinocyte released fibroblast mitogenic factor were evaluated by ELISA and (3)H-thymidine incorporation, respectively. Northern analysis was also employed to evaluate the expression of TGF-beta1, involucrin, TIMP-1, and 18 S ribosomal RNA in keratinocytes at different times of the onset of differentiation. The microscopic morphology of keratinocytes at different times of induction of cell differentiation showed detachments (nodules) of many regions of keratinocyte sheet from culture substratum within 1-2 weeks. The numbers and sizes of these nodules were increased as the process of keratinocyte differentiation proceed. The results of TGF-beta1 evaluation revealed that mono-layers of cultured keratinocytes which were round, attached, and proliferating in KSFM + BPE and EGF containing medium released a significantly higher level of TGF-beta1 (196 +/- 58 pg /ml) relative to those grown in multi-layer forms (28 +/- 7.8 pg/ml). A longitudinal experiment was then conducted and the results showed that cells on the onset of differentiation released even greater level of TGF-beta1 (388 +/- 53 pg/ml) relative to those grown in KSFM + BPE and EGF. This finding was consistent with the expression of TGF-beta1 mRNA evaluated in keratinocytes grown in test medium for various duration. In general, the level of TGF-beta1 protein and mRNA gradually reduced to its lowest level within 12 days of growing cells in our test medium. When aliquots of the collected keratinocyte conditioned medium were added to dermal fibroblasts, the level of (3)H-thymidine incorporation increased only in those cells receiving aliquots of conditioned medium containing high levels of TGF-beta1. When involucrin was used as a differentiation marker for keratinocytes at different time points, the highest level of involucrin mRNA expression was found at the later stage of cell differentiation. In conclusion, high involucrin expressing differentiated keratinocytes seem to be quiescent in releasing both TGF-beta1 and a fibroblast mitogenic factor.
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 ».