Regulatory effect of connexin 43 on basal Ca2+ signaling in rat ventricular myocytes.
BACKGROUND: It has been found that gap junction-associated intracellular Ca(2+) [Ca(2+)](i) disturbance contributes to the arrhythmogenesis and hyperconstriction in diseased heart. However, whether functional gaps are also involved in the regulation of normal Ca(2+) signaling, in particular the basa...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2012-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC3338611?pdf=render |
| _version_ | 1818202066670059520 |
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| author | Chen Li Qingli Meng Xinfeng Yu Xian Jing Pingxiang Xu Dali Luo |
| author_facet | Chen Li Qingli Meng Xinfeng Yu Xian Jing Pingxiang Xu Dali Luo |
| author_sort | Chen Li |
| collection | DOAJ |
| description | BACKGROUND: It has been found that gap junction-associated intracellular Ca(2+) [Ca(2+)](i) disturbance contributes to the arrhythmogenesis and hyperconstriction in diseased heart. However, whether functional gaps are also involved in the regulation of normal Ca(2+) signaling, in particular the basal [Ca(2+)](i) activities, is unclear. METHODS AND RESULTS: Global and local Ca(2+) signaling and gap permeability were monitored in cultured neonatal rat ventricular myocytes (NRVMs) and freshly isolated mouse ventricular myocytes by Fluo4/AM and Lucifer yellow (LY), respectively. The results showed that inhibition of gap communication by heptanol, Gap 27 and flufenamic acid or interference of connexin 43 (Cx43) with siRNA led to a significant suppression of LY uptake and, importantly, attenuations of global Ca(2+) transients and local Ca(2+) sparks in monolayer NRVMs and Ca(2+) sparks in adult ventricular myocytes. In contrast, overexpression of rat-Cx43 in NRVMs induced enhancements in the above measurements, and so did in HEK293 cells expressing rat Cx43. Additionally, membrane-permeable inositol 1,4,5-trisphosphate (IP(3) butyryloxymethyl ester) and phenylephrine, an agonist of adrenergic receptor, could relieve the inhibited Ca(2+) signal and LY uptake by gap uncouplers, whereas blockade of IP(3) receptor with xestospongin C or 2-aminoethoxydiphenylborate mimicked the effects of gap inhibitors. More importantly, all these gap-associated effects on Ca(2+) signaling were also found in single NRVMs that only have hemichannels instead of gap junctions. Further immunostaining/immunoblotting single myocytes with antibody against Cx43 demonstrated apparent increases in membrane labeling of Cx43 and non-junctional Cx43 in overexpressed cells, suggesting functional hemichannels exist and also contribute to the Ca(2+) signaling regulation in cardiomyocytes. CONCLUSIONS: These data demonstrate that Cx43-associated gap coupling plays a role in the regulation of resting Ca(2+) signaling in normal ventricular myocytes, in which IP(3)/IP(3) receptor coupling is involved. This finding may provide a novel regulatory pathway for mediation of spontaneous global and local Ca(2+) activities in cardiomyocytes. |
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| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-12T03:03:33Z |
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| spelling | doaj.art-26b631b20fbf47c6aad8846761ae357e2022-12-22T00:40:34ZengPublic Library of Science (PLoS)PLoS ONE1932-62032012-01-0174e3616510.1371/journal.pone.0036165Regulatory effect of connexin 43 on basal Ca2+ signaling in rat ventricular myocytes.Chen LiQingli MengXinfeng YuXian JingPingxiang XuDali LuoBACKGROUND: It has been found that gap junction-associated intracellular Ca(2+) [Ca(2+)](i) disturbance contributes to the arrhythmogenesis and hyperconstriction in diseased heart. However, whether functional gaps are also involved in the regulation of normal Ca(2+) signaling, in particular the basal [Ca(2+)](i) activities, is unclear. METHODS AND RESULTS: Global and local Ca(2+) signaling and gap permeability were monitored in cultured neonatal rat ventricular myocytes (NRVMs) and freshly isolated mouse ventricular myocytes by Fluo4/AM and Lucifer yellow (LY), respectively. The results showed that inhibition of gap communication by heptanol, Gap 27 and flufenamic acid or interference of connexin 43 (Cx43) with siRNA led to a significant suppression of LY uptake and, importantly, attenuations of global Ca(2+) transients and local Ca(2+) sparks in monolayer NRVMs and Ca(2+) sparks in adult ventricular myocytes. In contrast, overexpression of rat-Cx43 in NRVMs induced enhancements in the above measurements, and so did in HEK293 cells expressing rat Cx43. Additionally, membrane-permeable inositol 1,4,5-trisphosphate (IP(3) butyryloxymethyl ester) and phenylephrine, an agonist of adrenergic receptor, could relieve the inhibited Ca(2+) signal and LY uptake by gap uncouplers, whereas blockade of IP(3) receptor with xestospongin C or 2-aminoethoxydiphenylborate mimicked the effects of gap inhibitors. More importantly, all these gap-associated effects on Ca(2+) signaling were also found in single NRVMs that only have hemichannels instead of gap junctions. Further immunostaining/immunoblotting single myocytes with antibody against Cx43 demonstrated apparent increases in membrane labeling of Cx43 and non-junctional Cx43 in overexpressed cells, suggesting functional hemichannels exist and also contribute to the Ca(2+) signaling regulation in cardiomyocytes. CONCLUSIONS: These data demonstrate that Cx43-associated gap coupling plays a role in the regulation of resting Ca(2+) signaling in normal ventricular myocytes, in which IP(3)/IP(3) receptor coupling is involved. This finding may provide a novel regulatory pathway for mediation of spontaneous global and local Ca(2+) activities in cardiomyocytes.http://europepmc.org/articles/PMC3338611?pdf=render |
| spellingShingle | Chen Li Qingli Meng Xinfeng Yu Xian Jing Pingxiang Xu Dali Luo Regulatory effect of connexin 43 on basal Ca2+ signaling in rat ventricular myocytes. PLoS ONE |
| title | Regulatory effect of connexin 43 on basal Ca2+ signaling in rat ventricular myocytes. |
| title_full | Regulatory effect of connexin 43 on basal Ca2+ signaling in rat ventricular myocytes. |
| title_fullStr | Regulatory effect of connexin 43 on basal Ca2+ signaling in rat ventricular myocytes. |
| title_full_unstemmed | Regulatory effect of connexin 43 on basal Ca2+ signaling in rat ventricular myocytes. |
| title_short | Regulatory effect of connexin 43 on basal Ca2+ signaling in rat ventricular myocytes. |
| title_sort | regulatory effect of connexin 43 on basal ca2 signaling in rat ventricular myocytes |
| url | http://europepmc.org/articles/PMC3338611?pdf=render |
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