Significance of differentially expressed microRNAs and their target proteins in the development of autoimmune myocarditis in mouse model and patients

患者和动物易患自身免疫性心肌炎的原因尚不清楚。研究表明，一些小鼠品系(A/J和BALB/C)对实验性自身免疫性心肌炎敏感，而另一些品系(C57BL/6)则不敏感。在初步研究中，我们可以确定差异表达的microRNA(MiRs)，一种小的非编码寡核苷酸，与自身免疫性心肌炎的易感性有关。我们研究的目的是阐明自身免疫性心肌炎易感性不同的机制，并确定新的治疗靶点。在本研究中，我们将分析在C57BL/6株中上调的miRs的作用。由于miR-34a-5p和miR-135a-5p似乎对这些小鼠具有保护作用，我们将研究在C57BL/6小鼠中抑制这些miR如何影响自身免疫性心肌炎的易感性。此外，我们将分析这些miRs通过AAV9载体在A/J-小鼠和BALB/C-小鼠心脏中的过表达是否具有保护作用。最后，将评估这些MIR的靶蛋白如PNUTS在自身免疫性心肌炎中的作用。在另一种方法中，我们将研究在我们的自身免疫性心肌炎模型中，使用miR抑制剂(如miR-21a-5p或miR-146b-5p)治疗动物是否会减少或抑制炎症。此外，与这些MIR相关的新的信号通路也将被研究。特别是，我们将分析用AAV9载体过表达选定的靶蛋白(例如IRAK1、TRAF6、ERK1/2、Sprouty 1)是否能够预防EAM。在最后一步中，我们将调查在TNI免疫后易感小鼠的miR表达谱是否与在血液样本和心脏活检中分析的患者的miR表达谱相关。这些分析应该能够对人类自身免疫性心肌炎的易感性有新的见解，并导致确定新的治疗靶点。

Causes for a predisposition for an autoimmune myocarditis in patients as well as animals are still unknown. It has been shown that some mouse strains (A/J and BALB/C) are susceptible to the induction of an experimental autoimmune myocarditis and some are not (C57BL/6). In preliminary studies, we could identify a potential involvement of differentially expressed microRNA (miRs), small non-coding oligoribonucleotides, in the predisposition for an autoimmune myocarditis. The aim of our study is to elucidate the mechanisms involved in the different susceptibility to an autoimmune myocarditis and identify novel therapeutic targets. In this study, we will analyze the role of miRs upregulated in the C57BL/6 strain. Since miR-34a-5p and miR-135a-5p appear to be protective in these mice we will study how inhibiting these miRs in C57BL/6 mice affect the susceptibility to autoimmune myocarditis. Furthermore, we will analyze if the overexpression of these miRs via AAV9-vectors in the hearts of A/J- as well as BALB/C-mice will be protective. Finally, the role of target proteins of these miRs such as PNUTS in the disposition for an autoimmune myocarditis will be evaluated. In a further approach, we will investigate if treating animals with miR inhibitors against miRs upregulated in our model of autoimmune myocarditis such as miR-21a-5p or miR-146b-5p will reduce or inhibit an inflammation. Moreover, novel signaling pathways associated with these miRs will be investigated. In particular, we will analyze if the overexpression of selected target proteins (e.g. IRAK1, TRAF6, ERK1/2, Sprouty 1) with AAV9-vectors will be able to prevent an EAM. In a last step, we will investigate if the miR-expression profile of susceptible mice after TnI immunization correlates with the miR-expression profils of patients analyzed in blood samples and heart biopsies. These analyses should enable novel insights in the susceptibility to autoimmune myocarditis in humans and result in identification of novel therapeutic targets.