Phosphodiesterase Type 3A Regulates Basal Myocardial Contractility Through Interacting With Sarcoplasmic Reticulum Calcium ATPase Type 2a Signaling Complexes in Mouse Heart
Phosphodiesterase Type 3A Regulates Basal Myocardial Contractility Through Interacting With Sarcoplasmic Reticulum Calcium ATPase Type 2a Signaling Complexes in Mouse Heart
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DOI：
10.1161/circresaha.111.300003
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发表时间：
2013-01-18
影响因子：
20.1
通讯作者：
Backx, Peter H.
中科院分区：
文献类型：
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作者：
Beca, Sanja;Ahmad, Faiyaz;Backx, Peter H.
理由：cAMP是心肌功能的重要调节因子，环核苷酸磷酸二酯酶（PDEs）对cAMP水解的调节是cAMP介导的信号传导幅度、持续时间和区隔的关键决定因素。不同PDE同工酶，特别是PDE3A和PDE3B在心脏功能调节中的作用尚不清楚。目的：确定PDE3A与PDE3B同工酶在心功能调控中的相对贡献，并剖析其调控的分子基础。方法与结果：与野生型小鼠相比，PDE3A（-/-）小鼠离体心脏收缩性和舒张性增强，PDE3B（-/-）小鼠心脏收缩性和舒张性增强。此外，PDE3抑制对PDE3A（-/-）心脏没有影响，但将野生型（如预期的那样）和PDE3B（-/-）心脏的收缩力提高到与PDE3A（-/-）没有区别的水平。PDE3A（-/-）心脏的收缩力增强与camp依赖性Ca2+瞬态振幅升高和肌浆网（SR） Ca2+含量增加有关，心肌细胞的l型Ca2+电流没有变化，SR Ca2+- atpase 2a型活性增加，SR Ca2+摄取率增加，SR组分中磷蛋白磷酸化增加。与这些观察结果一致，PDE3活性在PDE3A（-/-）心脏的SR分数中降低了大约8倍。共免疫沉淀实验进一步发现，PDE3A与SR钙atp酶2a和磷蛋白结合在一个复合物中，该复合物还含有a激酶锚定蛋白-18、a - rii型蛋白激酶和2a型蛋白磷酸酶。结论：我们的数据支持PDE3A是主要的PDE3同工酶，通过调节含有SR钙ATPase型2a-磷蛋白-PDE3A大分子复合物的微结构域的cAMP来调节基础收缩性和SR Ca2+含量。（Circ Res. 2013;112:289-297.）
Rationale: cAMP is an important regulator of myocardial function, and regulation of cAMP hydrolysis by cyclic nucleotide phosphodiesterases (PDEs) is a critical determinant of the amplitude, duration, and compartmentation of cAMP-mediated signaling. The role of different PDE isozymes, particularly PDE3A vs PDE3B, in the regulation of heart function remains unclear.Objective: To determine the relative contribution of PDE3A vs PDE3B isozymes in the regulation of heart function and to dissect the molecular basis for this regulation.Methods and Results: Compared with wild-type littermates, cardiac contractility and relaxation were enhanced in isolated hearts from PDE3A(-/-), but not PDE3B(-/-), mice. Furthermore, PDE3 inhibition had no effect on PDE3A(-/-) hearts but increased contractility in wild-type (as expected) and PDE3B(-/-) hearts to levels indistinguishable from PDE3A(-/-). The enhanced contractility in PDE3A(-/-) hearts was associated with cAMP-dependent elevations in Ca2+ transient amplitudes and increased sarcoplasmic reticulum (SR) Ca2+ content, without changes in L-type Ca2+ currents of cardiomyocytes, as well as with increased SR Ca2+-ATPase type 2a activity, SR Ca2+ uptake rates, and phospholamban phosphorylation in SR fractions. Consistent with these observations, PDE3 activity was reduced approximate to 8-fold in SR fractions from PDE3A(-/-) hearts. Coimmunoprecipitation experiments further revealed that PDE3A associates with both SR calcium ATPase type 2a and phospholamban in a complex that also contains A-kinase anchoring protein-18, protein kinase type A-RII, and protein phosphatase type 2A.Conclusions: Our data support the conclusion that PDE3A is the primary PDE3 isozyme modulating basal contractility and SR Ca2+ content by regulating cAMP in microdomains containing macromolecular complexes of SR calcium ATPase type 2a-phospholamban-PDE3A. (Circ Res. 2013;112:289-297.)