Biophysical Modulation of Cardiac Ion Channels by MicroRNA

项目摘要 MicroRNAs(MiRs)是进化上保守的非编码小RNA分子，广泛参与 调节大多数生物事件；以前的研究主要集中在规范的mRNA干扰(RNAi)上 MIR的作用机制。在上一次融资期间，我们率先推出了一款进化的- 在其RNAi机制之外保守了miRs的新的生物物理作用。具体地说，我们揭示了一个 MiR1的新生物物理作用，它是心脏中最主要的miR，在 人类的心力衰竭。我们发现miR1在物理上与内向整流钾通道Kir2.1结合， 直接抑制IK1电流，并以生物物理方式调节心脏细胞的电生理。重要的是 我们发现miR1的人类单核苷酸多态(HSNP)--hSNP14A/G(Rs776480338)，在 其中第14位核苷酸“A”被突变为“G”，是一种仅RNAi的变体，它特异性地废除了生物物理 同时保持miR1的RNAi功能，验证生物物理调制是独立的 RNAi。我们的发现表明，miRs通过两种不同的机制调节心脏动态平衡： 1)规范的RNAi，调节蛋白质的表达，包括离子通道；2)新发现的 与蛋白质直接结合的机制，可迅速导致功能调节。有了这一重要的 新发现，现在当务之急是研究多个心脏离子通道是否受到 并阐明miR1‘S生物物理作用在心脏调节中的具体生理作用。 (电)生理学。根据我们公布的发现和初步数据，我们假设 MIR对心脏离子通道的生物物理调节是广泛存在的一种普遍的调节机制 在心脏的动态平衡中起着至关重要的作用。我们将以以下具体目标对此进行研究。1) 研究miR1对心脏离子通道的生物物理调制，2)了解生理学 MIR的生物物理作用对心脏的影响，3)揭示MIR的一般机制 心脏离子通道的生物物理调节。除了广泛的细胞活动外，还受到 大量的miRs(&gt；200种中的30,000 miRs)和离子通道，我们的研究将显著和 创新性地扩展了miR生物学和离子通道生物学的生物学意义，具有广泛的意义。 我们的发现开创了miR生物学的一个新领域，并将提供一个机械基础和新的 抗心律失常治疗的核糖核酸药物开发途径。

Project Summary MicroRNAs (miRs) are evolutionally conserved small non-coding RNA molecules that are broadly involved in regulating most biological events; previous studies have focused on the canonical mRNA interference (RNAi) mechanism of miRs. During the previous funding period, we were the first to unveil an evolutionarily- conserved novel biophysical action for miRs beyond its RNAi mechanism. Specifically, we revealed a novel biophysical action of miR1, which is the most predominant miR in the heart and is downregulated in human heart failure. We found that miR1 physically binds to an inward rectifier potassium channel Kir2.1, directly suppresses the IK1 current and biophysically modulates cardiac cellular electrophysiology. Importantly, we found that a human single nucleotide polymorphism (hSNP) of miR1–– hSNP14A/G (rs776480338), in which the 14th nucleotide “A” is mutated to “G”, is a RNAi-only variant that specifically abolishes the biophysical action while maintaining the RNAi function of miR1, validating that the biophysical modulation is independent of RNAi. Our discoveries suggest that miRs modulate cardiac homeostasis through two different mechanisms: 1) canonical RNAi that regulates the expression of proteins, including ion channels, and 2) newly-discovered mechanism of direct binding with proteins that quickly results in functional modulation. With this important new finding, it is now imperative to investigate if multiple cardiac ion channels are biophysically modulated by miRs and to elucidate the specific physiological impact of miR1’s biophysical action in the regulation of cardiac (electro)physiology. Based on our published findings and preliminary data, we hypothesize that the biophysical modulation of cardiac ion channels by miRs is a general regulatory mechanism that exists broadly and plays a critical role in the homeostasis of the heart. We will study this with the following specific aims. 1) To investigate the biophysical modulation of cardiac ion channels by miR1, 2) To understand the physiological impact of miRs’ biophysical action on the heart, 3) To unveil the general mechanisms guiding miRs’ biophysical modulation of cardiac ion channels. In addition to a broad range of cellular activities regulated by the large number of miRs (>30,000 miRs in >200 species) and ion channels, our study will significantly and innovatively expand the biological significance of miR biology and ion channel biology with broad implications. Our discoveries have pioneered a new field in miR biology and will provide a mechanistic foundation and new avenue of RNA-medicine development for antiarrhythmic therapy.