Self-replicating RNA-nanoplexes for programming monocytes to regenerate the heart

 描述：除了心脏移植，目前还没有能够恢复心肌梗死(MI)后心功能的治疗方法。心肌梗死导致数百万心脏细胞死亡 氧气和血液供应减少。使用神经调节蛋白(NRG1)等蛋白质刺激存活的心肌细胞有丝分裂的再生受损心肌细胞的策略可以部分恢复梗死心肌。然而，使用传统方法将这种疗法输送到心脏是困难的，原因有两个：(1)心脏血管对大分子的渗透性非常低，(2)到达心脏的分子会被高血流迅速冲走。在临床研究中，NRG1NRG1的S半衰期短，需要每天全身注射。此外，到达心脏的部分非常低，影响了其治疗效果。这种非靶向的方法还可能导致心脏偏远区域的心肌细胞不受控制地增殖，导致心肌增生和肥大。显然，迫切需要一种非侵入性和受控的给药方法，这种方法可以专门针对梗死区和交界区的存活心肌细胞。我们建议开发一种新的交付策略来满足这一需求。我们的方法将通过利用人体对心肌梗死的免疫反应来瞄准梗死的心脏组织。具体地说，我们建议使用自然迁移到梗死部位的单核细胞来传递再生蛋白。由于单核细胞与细胞外基质和其他蛋白质的特异性受体-配体相互作用，单核细胞在心脏中表现出非凡的滞留，尽管血液流量很高。我们假设(1)单核细胞可以被靶向并通过基因编程自复制的RNA纳米网络来表达NRG1，以及(2)单核细胞将成为梗塞组织的家园，并局部释放NRG1，一种可以诱导心肌细胞增殖和促进组织再生的蛋白质。为了验证这些假设，我们将首先产生以单核细胞为目标的自我复制的RNA-纳米网络，并对它们进行编程以表达NRG1。其次，我们将量化心肌梗死小鼠模型中基因编程为蛋白质生产的心肌梗死归巢单核细胞的数量。我们预计，这些研究将导致一个非侵入性的活药物储存库，并能够将蛋白质治疗药物局部输送到梗塞的SIE及其交界区。这对IHD患者的治疗和梗死心肌的再生具有深远的意义。

 DESCRIPTION: There are currently no treatments capable of restoring cardiac function after myocardial infarction (MI) besides cardiac transplantation. MI kills millions of heart cells due to reduced oxygen and blood supply. Strategies to regenerate damaged heart cells that use proteins, such as neuregulin (NRG1), to stimulate mitosis of surviving cardiomyocytes could partially restore infarcted myocardium. However, delivering such therapeutics to the heart using conventional methods is difficult for two reasons: (1) heart blood vessels show very low permeability for large molecules, (2) molecules that do reach the heart are washed away rapidly by the high blood flow. In clinical studies, NRG1's short half-life necessitates daily systemic injections. Further, the fraction that reaches the heart is very low, compromising its therapeutic efficacy. This non-targeted approach can also lead to the uncontrolled proliferation of cardiomyocytes in the remote zone of the heart, causing myocardial hyperplasia and hypertrophy. Clearly there is an urgent need for a non-invasive and controlled delivery approach that can specifically target surviving cardiomyocytes in the infarcted area and border zone. We propose to develop a novel delivery strategy that fulfills this need. Our approach will target infarcted cardiac tissue by exploiting the body's immunological response to MI. Specifically, we propose to deliver regenerating proteins using monocytes that naturally migrate to the site of infarction. Monocytes show extraordinary retention in the heart in spite of high blood flow due to specific receptor-ligand interactions with the extracellular matrix and other proteins. We hypothesize that (1) monocytes can be targeted and genetically programmed with self-replicating RNA-nanoplexes to express NRG1 and that (2) monocytes will home to infarcted tissue and locally release NRG1, a protein that can induce cardiomyocyte proliferation and facilitate tissue regeneration. To test these hypotheses, we will first generate self-replicating RNA-nanoplexes that target monocytes and program them to express NRG1. Secondly, we will quantify the number of MI-homing monocytes that are genetically programmed for protein production in a mouse model of MI. We anticipate that these studies will lead to a living drug reservoir that is non-invasive and able to locally deliver protein therapeutics to the infarcted sie and its border zone. This has profound implications for the treatment of patients with IHD and the regeneration of infarcted myocardium.