Basolateral chloride loading by the anion exchanger type 2: role in fluid secretion by the human airway epithelial cell line Calu‐3
Notice bibliographique
Résumé
Key points The companion paper provided evidence for basolateral anion exchange during cAMP stimulation of chloride and fluid secretion by Calu‐3 monolayers; however, the molecular basis of this transport was not identified. To test the role of AE2, an anion exchanger expressed at the basolateral membrane of Calu‐3 and many other epithelial cells, we used lentivirus‐mediated RNA interference to generate a stable Calu‐3 AE2 knock‐down cell line and characterized its fluid and anion transport properties. AE2 knock‐down suppressed fluid secretion and increased the fraction of cAMP‐stimulated anion secretion that was sensitive to bumetanide inhibition. Basolateral Cl − /HCO 3 − exchange was nearly abolished in AE2 knock‐down cells. We conclude that AE2 is active during forskolin‐stimulated fluid secretion and mediates chloride uptake and bicarbonate recycling at the basolateral membrane. Abstract Anion exchanger type 2 (AE2 or SLC4A2) is an electroneutral Cl − /HCO 3 − exchanger expressed at the basolateral membrane of many epithelia. It is thought to participate in fluid secretion by airway epithelia. However, the role of AE2 in fluid secretion remains uncertain, due to the lack of specific pharmacological inhibitors, and because it is electrically silent and therefore does not contribute directly to short‐circuit current ( I sc ). We have studied the role of AE2 in Cl − and fluid secretion by the airway epithelial cell line Calu‐3. After confirming expression of its mRNA and protein, a knock‐down cell line called AE2‐KD was generated by lentivirus‐mediated RNA interference in which AE2 mRNA and protein levels were reduced ≥90%. Suppressing AE2 increased the expression of the cystic fibrosis transmembrane conductance regulator (CFTR) by ∼70% without affecting the levels of NKCC1 (Na + –K + –2Cl − cotransporter) or NBCe1 (Na + –nHCO 3 − cotransporter). cAMP agonists stimulated fluid secretion by parental Calu‐3 and scrambled shRNA cells >6.5‐fold. In AE2‐KD cells this response was reduced by ∼70%, and the secreted fluid exhibited elevated pH and [HCO 3 − ] as compared with the control lines. Unstimulated equivalent short‐circuit current ( I eq ) was elevated in AE2‐KD cells, but the incremental response to forskolin was unaffected. The modest bumetanide‐induced reductions in both I eq and fluid secretion were more pronounced in AE2‐KD cells. Basolateral Cl − /HCO 3 − exchange measured by basolateral pH‐stat in cells with permeabilized apical membranes was abolished in AE2‐KD monolayers, and the intracellular alkalinization resulting from basolateral Cl − removal was reduced by ∼80% in AE2‐KD cells. These results identify AE2 as a major pathway for basolateral Cl − loading during cAMP‐stimulated secretion of Cl − and fluid by Calu‐3 cells, and help explain the large bumetanide‐insensitive component of fluid secretion reported previously in airway submucosal glands and some other epithelia.
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 distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 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) | 0,000 | 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 tête enseignante, 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 ».