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Conference Paper: cAMP/PKA-activated CFTR is required for acidosis-induced release of ATP from skeletal myocytes

TitlecAMP/PKA-activated CFTR is required for acidosis-induced release of ATP from skeletal myocytes
Authors
KeywordsCardiovascular disease
Issue Date2012
PublisherHong Kong College of Cardiology. The Journal's web site is located at http://www.hkcchk.com/journals.php#3
Citation
The 16th Annual Scientific Meeting of the Institute of Cardiovascular Science and Medicine (ICSM), Hong Kong, 17 November 2012. In Journal of the Hong Kong College of Cardiology, 2012, v. 20 n. 2, p. 50, abstract OP5 How to Cite?
AbstractATP is an extracellular signaling molecule involved in the regulation of skeletal muscle blood flow. Our previous study showed that depression of pH using lactic acid treatment stimulated the efflux of ATP from skeletal myocytes through a mechanism that involved the cystic fibrosis transmembrane conductance regulator (CFTR). The present study was undertaken to further explore the signal transduction mechanism linking the decrease in pH to the ATP release from muscle. Accumulation of ATP in the medium surrounding the myocytes was measured using a luminescence assay. Incubation of the myocytes in lactic acid (10 mM) for 3 hours increased the extracellular ATP from 0.67±0.08 to 1.15±0.11 nM (n=36; P<0.001). The specific inhibitor of CFTR, CFTRinh-172, inhibited the lactic-acid-induced increase in extracellular ATP. The CFTR expression was significantly increased with 3 hours incubation with lactic acid. Lactic acid treatment also increased the intracellular cAMP from 3.2±0.3 to 7.1±1.0 nM, and the Protein Kinase A (PKA) activity from 30.6±4.5 to 37.0±5.4 pmol/ml, whereas the lactic-acid-induced increase in extracellular ATP was inhibited by the PKA inhibitor, KT5720, but enhanced by the phosphodiesterase inhibitor IBMX, suggesting that the PKA/cAMP pathway was involved in CFTR activation. Furthermore, an in vivo phosphorylation study using 32P-ATP showed that CFTR phosphorylation was increased by forskolin alone or foskolin with dibutyryl-cAMP and IBMX, further supporting a role for the cAMP/PKA pathway in CFTR activation in muscle. Amiloride, an inhibitor of the Na/H exchanger (NHE), prevented the lactic-acid-induced increases in intracellular cAMP and extracellular ATP; inhibitors of the Na/Ca exchanger (NCX), SN-6 and KB-R7943, also inhibited the lactic-acid-induced accumulation of ATP in the medium surrounding the cultured myocytes. Based on these data, we propose that depression of the pH increases the efflux of ATP through a mechanism that involves CFTR activation through the cAMP/PKA pathway, and that NHE and NCX may be involved.
DescriptionThis journal issue contain abstracts of the 16th Annual Scientific Meeting of the Institute of Cardiovascular Science and Medicine 2012
Abstracts for Oral Presentation: OP5
Persistent Identifierhttp://hdl.handle.net/10722/191703
ISSN
2015 SCImago Journal Rankings: 0.102

 

DC FieldValueLanguage
dc.contributor.authorLu, Len_US
dc.contributor.authorTu, Jen_US
dc.contributor.authorBallard, HJen_US
dc.date.accessioned2013-10-15T07:19:26Z-
dc.date.available2013-10-15T07:19:26Z-
dc.date.issued2012en_US
dc.identifier.citationThe 16th Annual Scientific Meeting of the Institute of Cardiovascular Science and Medicine (ICSM), Hong Kong, 17 November 2012. In Journal of the Hong Kong College of Cardiology, 2012, v. 20 n. 2, p. 50, abstract OP5en_US
dc.identifier.issn1027-7811-
dc.identifier.urihttp://hdl.handle.net/10722/191703-
dc.descriptionThis journal issue contain abstracts of the 16th Annual Scientific Meeting of the Institute of Cardiovascular Science and Medicine 2012-
dc.descriptionAbstracts for Oral Presentation: OP5-
dc.description.abstractATP is an extracellular signaling molecule involved in the regulation of skeletal muscle blood flow. Our previous study showed that depression of pH using lactic acid treatment stimulated the efflux of ATP from skeletal myocytes through a mechanism that involved the cystic fibrosis transmembrane conductance regulator (CFTR). The present study was undertaken to further explore the signal transduction mechanism linking the decrease in pH to the ATP release from muscle. Accumulation of ATP in the medium surrounding the myocytes was measured using a luminescence assay. Incubation of the myocytes in lactic acid (10 mM) for 3 hours increased the extracellular ATP from 0.67±0.08 to 1.15±0.11 nM (n=36; P<0.001). The specific inhibitor of CFTR, CFTRinh-172, inhibited the lactic-acid-induced increase in extracellular ATP. The CFTR expression was significantly increased with 3 hours incubation with lactic acid. Lactic acid treatment also increased the intracellular cAMP from 3.2±0.3 to 7.1±1.0 nM, and the Protein Kinase A (PKA) activity from 30.6±4.5 to 37.0±5.4 pmol/ml, whereas the lactic-acid-induced increase in extracellular ATP was inhibited by the PKA inhibitor, KT5720, but enhanced by the phosphodiesterase inhibitor IBMX, suggesting that the PKA/cAMP pathway was involved in CFTR activation. Furthermore, an in vivo phosphorylation study using 32P-ATP showed that CFTR phosphorylation was increased by forskolin alone or foskolin with dibutyryl-cAMP and IBMX, further supporting a role for the cAMP/PKA pathway in CFTR activation in muscle. Amiloride, an inhibitor of the Na/H exchanger (NHE), prevented the lactic-acid-induced increases in intracellular cAMP and extracellular ATP; inhibitors of the Na/Ca exchanger (NCX), SN-6 and KB-R7943, also inhibited the lactic-acid-induced accumulation of ATP in the medium surrounding the cultured myocytes. Based on these data, we propose that depression of the pH increases the efflux of ATP through a mechanism that involves CFTR activation through the cAMP/PKA pathway, and that NHE and NCX may be involved.-
dc.languageengen_US
dc.publisherHong Kong College of Cardiology. The Journal's web site is located at http://www.hkcchk.com/journals.php#3en_US
dc.relation.ispartofJournal of the Hong Kong College of Cardiologyen_US
dc.subjectCardiovascular disease-
dc.titlecAMP/PKA-activated CFTR is required for acidosis-induced release of ATP from skeletal myocytesen_US
dc.typeConference_Paperen_US
dc.identifier.emailBallard, HJ: ballard@hkucc.hku.hken_US
dc.identifier.authorityBallard, HJ=rp00367en_US
dc.description.naturelink_to_OA_fulltext-
dc.identifier.hkuros225682en_US
dc.identifier.volume20en_US
dc.identifier.issue2en_US
dc.identifier.spage50en_US
dc.identifier.epage50en_US
dc.publisher.placeHong Kongen_US

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