TNNI3K: A cardiac-specific kinase regulating ischemic injury and fibrotic remodel

描述（由申请人提供）：心力衰竭通常由缺血性或高血压疾病引起，迫切需要新的策略来解决世界范围内不断扩大的心力衰竭患者群体。在过去的两年中，我们探索了一种新的心脏特异性蛋白激酶，肌钙蛋白I型3相互作用激酶（基因名称TNNI3K）在调节缺血性损伤，心肌梗死后重塑和压力过载诱导的重塑中的作用。我们采用了多种策略，包括1)转基因小鼠表达野生型、组成型活性或激酶非活性TNNI3K， 2)条件性心脏特异性TNNI3K缺失（CKO小鼠），以及3)由gsk - smith - kline的合作者生成的能够在体外和体内使用的新型TNNI3K小分子抑制剂。我们所有的数据都支持两个关键结论：1)TNNI3K的抑制作用很强

DESCRIPTION (provided by applicant): Heart failure commonly results from ischemic or hypertensive disease, and novel strategies are sorely needed to address the ever-expanding population of patients with heart failure world-wide. Over the past two years we have explored the role of a novel cardiac-specific protein kinase, troponin I type 3 interacting kinase (gene name TNNI3K) in regulating ischemic injury, post-MI remodeling, and pressure overload-induced remodeling. We have employed a number of strategies including 1) transgenic mice expressing either wild-type, constitutively active, or kinase-inactive TNNI3K, 2) conditional cardiac-specific deletion of TNNI3K (CKO mice), and 3) novel small molecule inhibitors of TNNI3K generated by our collaborators at Glaxo-Smith-Kline that are able to be used both in vitro and in vivo. All of our data support two key conclusions: 1) Inhibition of TNNI3K is strongly protective, and activation of TNNI3K is highly detrimental, in the setting of ischemia/reperfusion (I/R) injury, and 2) TNNI3K appears to be a central regulator of fibrotic remodeling in the heart. We now propose to determine the molecular mechanisms by which TNNI3K regulates these processes, thereby expanding our understanding of mechanisms of ischemic injury and repair. In our Specific Aims we propose to identify TNNI3K targets from genomic analyses and have already identified a profound role of TNNI3K in regulating expression of genes implicated in fibrotic remodeling. This is consistent with the significant reduction in fibrosis we observe in mice subjected to thoracic aortic constriction that were treated with one of the small molecule inhibitors. We will also employ proteomic approaches to identify direct substrates of TNNI3K using the analog sensitive kinase allele (ASKA) approach pioneered by Shokat and co-workers. Finally, we will focus on the role of select substrates identified in Aim 2, and will determine ther role in ischemic injury and post-infarct remodeling. Given our successful use of small molecule inhibitors targeting TNNI3K in vivo, and the demonstrated safety of this approach in our pre-clinical models, we believe that the stage could be set for fairly rapid translation to clinical trals if our hypotheses are borne out.