Expression and function of microRNA in autoimmune Sjogren's Syndrome

描述(申请人提供)：自身免疫性干燥综合征(SjS)主要针对女性个体的外分泌腺，如唾液腺和泪腺，导致严重的分泌功能障碍及其并发症。由于干燥综合征发病机制的复杂性，迄今尚无针对干燥综合征的特异性诊断和治疗方法。MicroRNAs(MiRNAs)是一类重要的非编码RNA，参与多种生物学、病理学和免疫学过程。我们最新发现的miR-146a和-155在原发性SjS患者外周血单核细胞(PBMC)或单核细胞中的表达变化与健康对照组相比，表明miRNAs可能在SjS自身免疫的启动和发展中发挥关键作用。在我们的pSjS倾向于C57BL/6.NOD-Aec1Aec2小鼠模型的唾液腺和PBMC中的发现进一步支持了这些数据，这些miRNAs从很小的时候就被观察到上调。在我们的初步研究中，miR-146a在人单核细胞系(THP-1)中的过表达能够改变吞噬和促炎细胞因子产生等先天免疫反应。我们现在提出的研究旨在检验我们的假设，即miR-146a和miR-155通过改变先天免疫反应对于延长炎症过程至关重要，并且特别涉及先天免疫的pSjS特异性miRNAs可以差异表达(甚至可能在疾病发生之前导致持续炎症)。在本项目的目标1中，我们将利用miRNA模拟物和抑制剂导入THP-1细胞，然后进行功能分析，以研究改变miR-146a和/或miR-155的后果。改变的功能也将在pSjS患者的原代培养单核细胞中进行测试。这一目的是为了确定miRNAs对免疫基因的表观遗传调控是否在改变SjS的免疫过程中起关键作用。在目标2中，我们将开始利用miRNA微阵列方法来描述参与PSI的miRNAs的复杂网络。在这里，我们将测试我们的假设，即针对人类pSjS的miRNA图谱是可识别的。此外，我们将继续在Aim 2中鉴定差异表达的miRNAs的靶基因，并进行在Aim 1中建立的功能分析，以筛选它们参与先天性免疫反应。我们预计，这些实验将发现pSjS中新的miRNAs，以及已识别的miRNAs在Sjs异常免疫调节中的调节功能，并最终可能有助于生物标志物的开发和治疗干预。

DESCRIPTION (provided by applicant): Autoimmune Sj"gren's syndrome (SjS) targets the exocrine glands, such as the salivary and lacrimal glands, of mostly female individuals, leading to severe secretory dysfunction and its complications. To date, SjS- specific diagnostics and therapeutics have not been available due to complexity of SjS disease pathogenesis. MicroRNAs (miRNAs) have been recognized as an important class of non-coding RNAs that are involved in a variety of biological, pathological, and immunological processes. Our latest findings on altered miR-146a and- 155 expression in peripheral blood mononuclear cells (PBMC) or monocytes of primary SjS (pSjS) patients in comparison with healthy controls indicate that miRNAs may play a critical role in autoimmune initiation and progression of SjS. The data were further supported by the findings in the salivary glands and PBMC of our pSjS-prone C57BL/6.NOD-Aec1Aec2 mouse model, where up-regulation of those miRNAs was observed from an early age on. Over-expression of miR-146a in human monocyte cell line (THP-1) was able to alter innate immune responses such as phagocytosis and pro-inflammatory cytokine production in our preliminary study in vitro. We now propose studies designed to test our hypotheses that miR-146a and miR-155 are vital to prolong inflammatory processes by altering innate immune response and that pSjS-specific miRNAs especially involved in innate immunity can be differentially expressed (potentially even prior to disease onset resulting in persistent inflammation). In Aim 1 of this project, we will investigate consequences of altered miR-146a and/or miR-155 by utilizing miRNA mimics and inhibitors transfected into THP-1 cells followed by functional assays. Altered functions will also be tested in primary cultured monocytes from pSjS patients. This aim is to determine if epigenetic regulation of immune genes by miRNAs are critical in altering immunological processes in SjS. In Aim 2, we will begin to profile a complex network of miRNAs involved in pSiS by utilizing a miRNA microarray approach. Here we will test our hypothesis that miRNA profiles that are specific for human pSjS are identifiable. Furthermore, we will continue to identify in Aim 2 target genes of differentially expressed miRNAs and perform functional assays established in Aim 1 to screen their involvement in innate immune responses. We envision that these experiments will identify novel miRNAs in pSjS and regulatory functions of identified miRNAs in abnormal immune regulation of SjS and may ultimately be amenable to development of biomarkers and therapeutic intervention.