The calcium and integrin binding protein (CIB)1 as therapeutic target in heart failure

心脏的病理性负荷，例如在动脉高压、主动脉瓣狭窄或心肌梗死期间，会引发心脏肥厚，最终导致心力衰竭。在欧洲，大约有1000万人患有心力衰竭，这仍然与高发病率和死亡率有关。因此，需要新的治疗策略。我们在之前的工作中证明，心肌细胞中的接头蛋白CIB1特异性地促进病理性的、适应性不良的肥大，而不是生理性的（适应性）肥大，因为它发生在运动员身上，与疾病无关。因此，小鼠CIB1基因缺失可防止病理性肥厚和心力衰竭的发生。CIB1通过将肥厚性磷酸酶钙调磷酸酶募集到细胞膜上，从而促进心肌细胞的生长，在细胞膜上，它可以在一个特殊的微域内被激活。在这个提议中，我们的目标是建立转化治疗概念来抑制CIB1在心肌中。首先，我们希望在基因治疗方法中使用短发夹RNA （shCIB1）下调CIB1。为此，我们开发了一种用腺相关病毒（AAV）过表达shCIB1的策略。我们现在的目标是测试AAV-shCIB1对实验性小鼠主动脉收缩或心肌梗死后肥厚和心力衰竭发展的影响。其次，我们的目标是确定一种化学成分，它可以阻断CIB1和钙调磷酸酶的结合，从而抑制心脏肥厚和心力衰竭。我们建立了一种哺乳动物双杂交实验，可以定量测定CIB1和钙调磷酸酶之间的相互作用。在柏林莱布尼茨分子药理学研究所的帮助下，我们希望筛选40000种确定的化学物质对CIB1/钙调磷酸酶相互作用的抑制作用。阳性物质将首先在分离的心肌细胞中测试其抗肥厚和钙调磷酸酶抑制作用。我们的长期目标是将这些转化概念用于心力衰竭患者的临床应用。

Pathological overload of the heart for example during arterial hypertension, aortic valve stenosis or myocardial infarction triggers cardiac hypertrophy and ultimately heart failure. In Europe around 10 million people suffer from heart failure, which is still associated with high morbidity and mortality. Therefore, new therapeutic strategies are needed. We demonstrated in our previous work that the adaptor protein CIB1 in cardiomyocytes specifically promotes pathological, maladaptive hypertrophy, but not physiological (adaptive) hypertrophy as it occurs for example in athletes, where it is not associated with disease. Consequently, genetic deletion of CIB1 in mice protects against the development of pathological hypertrophy and heart failure. CIB1 promotes cardiomyocyte growth by recruiting the prohypertrophic phosphatase calcineurin to the cell membrane where it can get activated within a specialized microdomain. Within this proposal we aim to establish translational therapeutic concepts to inhibit CIB1 in the myocardium. First, we want to downregulate CIB1 with a short-hairpin RNA (shCIB1) in a gene-therapeutic approach. For this purpose we developed a strategy to overexpress shCIB1 with an adeno-associated virus (AAV) 9. We now aim to test the effects of AAV-shCIB1 on hypertrophy and heart failure development after experimental aortic constriction or myocardial infarction in mice. Secondly, we aim to identify a chemical component that interrupts the association of CIB1 and calcineurin and consequently inhibits cardiac hypertrophy and heart failure. We established a mammalian two-hybrid assay that allows quantification of the interaction between CIB1 and calcineurin. With the help of the Leibniz Institute of Molecular Pharmacology in Berlin we want to screen 40.000 defined chemical substances for an inhibitory effect on the CIB1/calcineurin interaction. Positive substances will be tested for their antihypertrophic and calcineurin inhibiting effects at first in isolated cardiomyocytes. Our long-term goal is to develop these translational concepts towards clinical application in patients with heart failure.