Uridylation of miRNAs by ZCCHC6 Regulates IL-6 Expression in Arthritis

 描述（由申请人提供）：摘要估计有2700万25岁及以上的美国人患有骨关节炎（OA），这是一种关节软骨的退行性疾病，其特征在于软骨基质（主要是胶原和蛋白聚糖）的损失，导致关节组织破坏和功能丧失。在45岁之前，男性比女性更多患有骨关节炎; 45岁之后，女性更常见。促炎细胞因子IL-6最近由于其在来自OA患者的滑液和血清中的水平升高以及其对关节炎的抑制作用的能力而受到关注。 上调MMP-13的表达，抑制II型胶原的表达。成熟的miRNA是抑制靶mRNA的翻译和稳定性的非编码RNA，并且现在已知经历非模板核苷酸（主要是尿苷）添加到3'末端（3' NTA）。负责miRNA的3'末端修饰的酶最近才在癌症和免疫细胞中被鉴定，但尚未在软骨或软骨细胞中被描述。我们的初步数据显示：（1）ZCCHC 6-一种核苷酸转移酶-在受损的OA软骨中高度表达;（2）调节人软骨细胞中IL-6的表达。已知ZCCHC 6使mRNA尿苷酸化，因此表明ZCCHC 6介导的miRNA 3 '末端修饰可能在OA中IL-6以及可能的其他炎症介质的转录后调节中发挥重要作用。我们将追求4个具体的目标来测试基本假设，即ZCCHC 6使软骨细胞中的成熟miRNA尿苷酸化以调节OA中的IL-6表达和炎症。具体目标-1。研究将检验“细胞因子靶向miRNA在OA软骨中被尿苷酸化”的假设。具体目标-2。我们将检验“miRNA尿苷化消除人OA软骨细胞中IL-6表达的抑制”的假设。具体目标-3。我们将检验“ZCCHC 6的表达对于人OA软骨细胞中IL-6的表达是必需的”这一假设。具体目标-4。在人类OA的动物模型中，我们将检验“ZCCHC 6介导miRNA尿苷酸化并在疾病的诱导和进展期间调节IL-6表达”的假设。从这些研究中获得的知识将是重要的，因为通过了解miRNA 3 '端修饰如何影响OA中炎症介质的表达，可能会导致开发新的生物标志物和有效治疗OA的疗法。

 DESCRIPTION (provided by applicant): Abstract An estimated 27 million Americans age 25 and older have osteoarthritis (OA), a degenerative disease of articular cartilage characterized by loss of the cartilage matrix, mainly collagen and proteoglycans, leading to joint tissue destruction and loss of function. Before age 45, more men than women have osteoarthritis; after age 45, it is more common in women. The pro-inflammatory cytokine IL-6 has recently gained interest due to its elevated levels in synovial fluid and sera from OA patients and its capacity to upregulate the expression of MMP-13 and inhibit the expression of type-II collagen. Mature miRNAs are non-coding RNAs that inhibit the translation and stability of target mRNAs and are now known to undergo addition of non-template nucleotides (largely uridines) to the 3' ends (3'NTAs). The enzymes responsible for 3' end modifications of miRNAs have only recently been identified in cancer and immune cells but have not yet been described in cartilage or chondrocytes. Our preliminary data show that (1) ZCCHC6-a nucleotidyl transferase-is highly expressed in damaged OA cartilage; and (2) regulates IL-6 expression in human chondrocytes. ZCCHC6 is known to uridylate mRNAs thus suggesting that ZCCHC6-mediated miRNA 3'end modifications could play a significant role in the post-transcriptional regulation of IL-6, and possibly of other inflammatory mediators, in OA. We will pursue 4 specific aims to test the fundamental hypothesis that ZCCHC6 uridylates mature miRNAs in chondrocytes to regulate IL-6 expression and inflammation in OA. Specific Aim-1. Studies will test the hypothesis that "cytokine targeting miRNAs are uridylated in OA cartilage". Specific Aim-2. We will test the hypothesis that "miRNA uridylation abrogates repression of IL-6 expression in human OA chondrocytes". Specific Aim-3. We will test the hypothesis that "expression of ZCCHC6 is essential for IL-6 expression in human OA chondrocytes". Specific Aim-4. In an animal model of human OA we will test the hypothesis that "ZCCHC6 mediates miRNA uridylation and regulate IL-6 expression during the induction and progression of the disease". Knowledge gained from these studies will be important since by understanding how miRNA 3'end modifications affect the expression of inflammatory mediators in OA may lead to the development of novel biomarkers and therapies for the effective treatment of OA.