MicroRNA In Diabetic Nephropathy

描述（由申请人提供）：本申请的长期目标是鉴定可能导致糖尿病肾病（DN）进展的肾脏microRNAs （miRNAs）及其靶基因。MicroRNAs是一类高度保守的非编码rna，它们通过抑制mrna的翻译或破坏mrna的稳定而成为基因表达的负调控因子。由于个体经常调节多个具有相关功能的靶基因的表达，原则上，单个microRNA的失调可以影响整个基因网络，从而导致复杂的疾病表型，如DN。目前提出的研究的主要目的是评估microRNA-93 （miR-93）在DN中的致病作用。我们的主要假设是miR-93通过其对VEGF信号通路的调节参与DN的发病机制。我们的假设是基于几个新的观察结果：1)我们最近发现，基于比较microRNA阵列，miR-93是糖尿病环境中的“标志性”miRNA; 2)我们首次发现，miR-93在体外和体内高血糖状态下调节VEGF-A表达中起着关键作用（Long J. et al.）。生物。Chem. 2010)，以及3)在VEGF表达的诱导小鼠模型中，靶向miR-93导致VEGF分泌显著增加。基于这些初步观察，我们现在提出了一种综合的体外和体内方法来测试三个特定的目标。目的1：评估miR-93在DN小鼠模型中的条件组织特异性强制表达的影响。目的2：确定miR-93在体外和体内发挥作用的分子靶点。目的3：表征小鼠足细胞中miR-93启动子的葡萄糖反应元件（GRE）。这一应用的发现将在三个方面提供重大进展：首先，这一建议代表了一种新的治疗方法，并有可能在对抗糖尿病肾病方面提供一类新的药物。其次，我们的研究不仅将揭示miR-93在高血糖状态中的作用，还将揭示VEGF在糖尿病肾病中的病理生物学作用。第三，我们将建立遗传模型来证实miR-93直接参与DN的发病机制。该遗传模型将为miR- 93的作用及其在DN中的潜在靶点提供更多信息。

DESCRIPTION (provided by applicant): The long-term objective of this proposal is to identify renal microRNAs (miRNAs) and their target genes that could potentially contribute to the progression of diabetic nephropathy (DN). MicroRNAs constitute a class of highly conserved noncoding RNAs that act as negative regulators of gene expression by either inhibiting the translation of mRNAs or destabilizing them. Because individual often regulate the expression of multiple target genes with related functions, dysregulation of a single microRNA can, in principle, microRNAs influence an entire gene network and thereby contribute to complex disease phenotypes such as DN. The main aim of the current proposed study is to evaluate the pathogenic role of microRNA-93 (miR-93) in DN. Our main hypothesis is that miR-93 contributes to the pathogenesis of DN via its modulatory involvement on VEGF signaling pathway. Our hypothesis is based on several novel observations: 1) we have recently shown miR-93 is a "signature" miRNA in the diabetic milieu based on comparative microRNA arrays, 2), we have shown for the first time that miR-93 plays a critical role in regulating VEGF-A expression in hyperglycemic conditions in vitro and in vivo (Long J. et al. J. Biol. Chem. 2010), and 3) targeting of miR-93 leads to a significant increase in VEGF secretion in an inducible mouse model of VEGF expression. Based upon these initial observations, we now propose an integrated in vitro and in vivo approach to test three specific aims. Aim 1: Assess the effect of conditional tissue-specific forced expression of miR-93 in the murine models of DN, Aim 2: Define the molecular targets through which miR-93 exerts its effect in vitro and in vivo. Aim 3: Characterization of glucose-responsive elements (GRE) of the mouse miR-93 promoter in podocytes. The findings of this application will provide a significant advance in three aspects: first, this proposal represents a new therapeutic approach, and potentially a new class of agents in the fight against diabetic kidney disease. Second, our research will shed light not only on the role of miR-93 in hyperglycemic conditions, but also on the pathobiology of VEGF in diabetic nephropathy. And third, we will generate a genetic model to confirm that miR-93 is directly involved in the pathogenesis of DN. This genetic model will provide additional information on the role of miR- 93, and its potential targets in DN.