Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany.
Cells. 2021 Mar 3;10(3):535. doi: 10.3390/cells10030535.
3',5'-Cyclic adenosine monophosphate (cAMP) is a ubiquitous second messenger which plays critical roles in cardiac function and disease. In adult mouse ventricular myocytes (AMVMs), several distinct functionally relevant microdomains with tightly compartmentalized cAMP signaling have been described. At least two types of microdomains reside in AMVM plasma membrane which are associated with caveolin-rich raft and non-raft sarcolemma, each with distinct cAMP dynamics and their differential regulation by receptors and cAMP degrading enzymes phosphodiesterases (PDEs). However, it is still unclear how cardiac disease such as hypertrophy leading to heart failure affects cAMP signals specifically in the non-raft membrane microdomains. To answer this question, we generated a novel transgenic mouse line expressing a highly sensitive Förster resonance energy transfer (FRET)-based biosensor E1-CAAX targeted to non-lipid raft membrane microdomains of AMVMs and subjected these mice to pressure overload induced cardiac hypertrophy. We could detect specific changes in PDE3-dependent compartmentation of β-adrenergic receptor induced cAMP in non-raft membrane microdomains which were clearly different from those occurring in caveolin-rich sarcolemma. This indicates differential regulation and distinct responses of these membrane microdomains to cardiac remodeling.
3'，5'-环磷酸腺苷（cAMP）是一种普遍存在的第二信使，在心脏功能和疾病中发挥着关键作用。在成年小鼠心室肌细胞（AMVM）中，已经描述了几个具有紧密分隔的 cAMP 信号传导功能相关的微区。至少有两种类型的微区存在于 AMVM 质膜中，它们与富含窖蛋白的筏和非筏质膜相关，每个微区都具有独特的 cAMP 动力学，并且其受受体和 cAMP 降解酶磷酸二酯酶（PDEs）的差异调节。然而，仍然不清楚心脏疾病（如导致心力衰竭的肥大）如何具体影响非筏膜微区中的 cAMP 信号。为了回答这个问题，我们生成了一种新型的转基因小鼠系，该系表达了一种高度敏感的基于Förster 共振能量转移（FRET）的生物传感器 E1-CAAX，该传感器靶向 AMVM 的非脂筏质膜微区，并对这些小鼠进行了压力超负荷诱导的心脏肥大。我们可以检测到非筏质膜微区中β肾上腺素能受体诱导的 cAMP 与 PDE3 相关的分区的特定变化，这些变化与窖蛋白丰富的质膜中发生的变化明显不同。这表明这些膜微区的调节存在差异，对心脏重构的反应也不同。
