P2Y receptor regulation of K2P channels that facilitate K+ secretion by human mammary epithelial cells
| Autor: | Chatsri Deachapunya, Scott M. O'Grady, Yotesawee Srisomboon, Nathan A. Zaidman, Peter J. Maniak |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Epithelial sodium channel P2Y receptor Physiology Uridine Triphosphate Membrane Potentials 03 medical and health sciences Potassium Channels Tandem Pore Domain Potassium Channel Blockers Humans Secretion Na+/K+-ATPase Epithelial Sodium Channels Mammary Glands Human Ion channel Ion transporter Protein Kinase C Cell Line Transformed Secretory Pathway Chemistry Purinergic receptor Sodium Epithelial Cells Cell Biology Cell biology 030104 developmental biology Mammary Epithelium Receptors Purinergic P2Y Potassium Female Purinergic P2Y Receptor Agonists Research Article |
| Popis: | The objective of this study was to determine the molecular identity of ion channels involved in K+ secretion by the mammary epithelium and to examine their regulation by purinoceptor agonists. Apical membrane voltage-clamp experiments were performed on human mammary epithelial cells where the basolateral membrane was exposed to the pore-forming antibiotic amphotericin B dissolved in a solution with intracellular-like ionic composition. Addition of the Na+ channel inhibitor benzamil reduced the basal current, consistent with inhibition of Na+ uptake across the apical membrane, whereas the KCa3.1 channel blocker TRAM-34 produced an increase in current resulting from inhibition of basal K+ efflux. Treatment with two-pore potassium (K2P) channel blockers quinidine, bupivacaine and a selective TASK1/TASK3 inhibitor (PK-THPP) all produced concentration-dependent inhibition of apical K+ efflux. qRT-PCR experiments detected mRNA expression for nine K2P channel subtypes. Western blot analysis of biotinylated apical membranes and confocal immunocytochemistry revealed that at least five K2P subtypes (TWIK1, TREK1, TREK2, TASK1, and TASK3) are expressed in the apical membrane. Apical UTP also increased the current, but pretreatment with the PKC inhibitor GF109203X blocked the response. Similarly, direct activation of PKC with phorbol 12-myristate 13-acetate produced a similar increase in current as observed with UTP. These results support the conclusion that the basal level of K+ secretion involves constitutive activity of apical KCa3.1 channels and multiple K2P channel subtypes. Apical UTP evoked a transient increase in KCa3.1 channel activity, but over time caused persistent inhibition of K2P channel function leading to an overall decrease in K+ secretion. |
| Databáze: | OpenAIRE |
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