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MK571‐sensitive extracellular ATP release in intestinal epithelia
Author(s) -
Nakano Takanari,
Akiba Yasutada,
Engel Eli,
Guth Paul H,
Kaunitz Jonathan D
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.1014.2
Subject(s) - pannexin , extracellular , atp binding cassette transporter , atpase , atp hydrolysis , adenosine triphosphate , purinergic receptor , biochemistry , microbiology and biotechnology , v atpase , chemistry , apyrase , caco 2 , transporter , biology , enzyme , intracellular , connexin , cell , gap junction , gene
Epithelial ATP release is an essential component of purinergic secretory regulation. Although the mechanism of extracellular ATP release from epithelial cells is unknown, the involvement of ATP channels, such as pannexin hemichannels and the ATP‐binding cassette (ABC) transporters has been hypothesized. We measured extracellular ATP release from confluent Caco‐2 cell monolayers in order to further study this mechanism. Ecto‐ATPase activity of alkaline phosphatase, CD39, 5′‐nucleotidase, and other brush border ecto‐enzymes was inhibited by non‐cytotoxic concentrations of EDTA, enabling the measurement of supernatant ATP using the luciferin‐luciferase assay. In the presence of EDTA, [ATP] increased linearly, consistent with constitutive cellular ATP release. Among the pharmacological reagents reported as inhibitors for ATP release, MK571, a specific multidrug resistant‐associated protein (MRP) inhibitor dose‐dependently inhibited the ATP release, with no inhibition due to stilbene anion transport inhibitors, pannexin inhibitors, or multidrug resistance protein (MDR) 1 substrates. These results suggest MRP‐associated ATP release in intestinal epithelia, a novel mechanism for transmembrane ATP transport. NIH‐NIDDK R01 DK54221 & R21 DK081199