MicroRNAs,immune cells and pregnancy

MicroRNAs （miRNAs） are a recently discovered class of non-coding RNAs that are expressed in many cell types, where they regulate the expression of complementary RNAs, thus modulating the stability and translation of mRNAs, miRNAs are predicted to regulate the expression of -50% of all protein coding genes in mammals. Therefore, they participate in virtually all cellular processes investigated so far. Altered miRNAs expressions are associated with both physiological （pregnancy） and pathological processes （cancer）. As the dynamic maternal-fetal interface plays a critical role in the maintenance of successful pregnancy, it is not surprising that the miRNAs that are unique to reproductive tissues are abundantly expressed. Research in this field has demonstrated the presence and dysregulation of a distinct set of pregnancy-associated miRNAs; however, most studies have centered on localizing various miRNAs in reproductive microdomains associated with normal or complicated pregnancies. Although several independent miRNA regulatory mechanisms associated with endometrial receptivity, immune cells, angiogenesis and placental development have been studied, miRNA-mediated regulation of pregnancy remains poorly understood. This review provides a summary of the current data on miRNA regulation as well as functional profiles of miRNAs that are found in the uterus, in immune cells associated with maternal tolerance to the fetus, and those involved in angiogenesis and placental development.     

Primary biliary cirrhosis is associated with altered hepatic microRNA expression

MicroRNAs (miRNAs) are small RNA molecules that negatively regulate protein coding gene expression and are thought to play a critical role in many biological processes. Aberrant levels of miRNAs have been associated with numerous diseases and cancers, and as such, miRNAs have gain much interests as diagnostic biomarkers, and as therapeutic targets. However, their role in autoimmunity is largely unknown. The aims of this study are to: (1) identify differentially expressed miRNAs in human primary biliary cirrhosis (PBC); (2) validate these independently; and (3) identify potential targets of differentially expressed miRNAs. We compared the expression of 377 miRNAs in explanted livers form subjects with PBC versus controls with normal liver histology. A total of 35 independent miRNAs were found to be differentially expressed in PBC (p < 0.001). Quantitative PCR was employed to validate down-regulation of microRNA-122a (miR-122a) and miR-26a and the increased expression of miR-328 and miR-299-5p. The predicted targets of these miRNAs are known to affect cell proliferation, apoptosis, inflammation, oxidative stress, and metabolism. Our data are the first to demonstrate that PBC is characterized by altered expression of hepatic miRNA; however additional studies are required to demonstrate a causal link between those miRNA and the development of PBC.     

microRNAs和自身免疫性疾病

microRNAs（miRNAs）是一类进化上保守的微小非编码RNA,通过与靶基因mRNA3’端非翻译区相互作用致使mRNA降解或翻译抑制,在转录后水平调控基因表达,进而影响细胞周期、分化及凋亡等多种细胞生理过程。nfiRNAs在免疫系统的发育及功能行使中具有重要调控作用。研究表明,miRNAs在多种自身免疫性疾病中表达异常,提示miRNAs在自身免疫性疾病的发生发展及防治中具有重大作用。     

The Role of MicroRNAs in Autoimmune Diseases with Skin Involvement

MicroRNAs (miRNAs) are small non‐coding RNA molecules that negatively modulate gene expression by binding to the 3′ untranslated region (UTR) of target messenger RNAs (mRNAs), which leads to the degradation or translational repression of their target mRNAs. Previous research on miRNAs has revealed a new paradigm of gene regulations and pathways involved in the pathogenesis of autoimmune disorders and malignant diseases. The roles of miRNAs in cellular processes, including cell differentiation, proliferation, apoptosis and immune functions, are not clearly understood. MiRNAs are easily detected in a variety of sources, including tissues, serum and other body fluids, and this make them a good biological sample for pathogenic studies and disease biomarker development. This review encompasses the current understanding of the roles of miRNAs in autoimmunity and the cellular and molecular mechanisms of miRNAs in various autoimmune diseases (AIMDs). Specifically, we focus on the target genes of miRNAs and the biological processes associated with autoimmune diseases with skin involvement, including systemic lupus erythematosus, psoriasis, systemic sclerosis, Behcet's disease and dermatomyositis. In addition, the diagnostic and therapeutic relevance of miRNAs that are involved in autoimmunity are elucidated to provide information for clinical implications.     

Pervasive regulation of Drosophila Notch target genes by GY-box-, Brd-box-, and K-box-class microRNAs

Although hundreds of distinct animal microRNAs (miRNAs) are known, the specific biological functions of only a handful are understood at present. Here, we demonstrate that three different families of Drosophila miRNAs directly regulate two large families of Notch target genes, including basic helix-loop-helix (bHLH) repressor and Bearded family genes. These miRNAs regulate Notch target gene activity via GY-box (GUCUUCC), Brd-box (AGCUUUA), and K-box (cUGUGAUa) motifs. These are conserved sites in target 3'-untranslated regions (3'-UTRs) that are complementary to the 5'-ends of miRNAs, or "seed" regions. Collectively, these motifs represent >40 miRNA-binding sites in Notch target genes, and we show all three classes of motif to be necessary and sufficient for miRNA-mediated regulation in vivo. Importantly, many of the validated miRNA-binding sites have limited pairing to miRNAs outside of the "box:seed" region. Consistent with this, we find that seed-related miRNAs that are otherwise quite divergent can regulate the same target sequences. Finally, we demonstrate that ectopic expression of several Notch-regulating miRNAs induces mutant phenotypes that are characteristic of Notch pathway loss of function, including loss of wing margin, thickened wing veins, increased bristle density, and tufted bristles. Collectively, these data establish insights into miRNA target recognition and demonstrate that the Notch signaling pathway is a major target of miRNA-mediated regulation in Drosophila.     

miR-132在神经系统疾病中作用的研究进展

MicroRNAs(miRNAs)作为基因表达的关键调控因子,主要通过在转录后调控大量靶信使RNA(messenger RNA,mRNA)的表达,参与大部分生物学过程以及许多疾病的发病机制。miR-132的表达在神经元发育、成熟过程中是必要的。同时,miR-132作为一种最重要的神经相关miRNAs之一,在神经系统和免...     

MicroRNA参与的调控网络

成熟的microRNA(miRNA)是一类长约18～24个核苷酸、内源性非编码小RNA分子,它在体内下调靶基因的表达。迄今在不同物种中已发现的miRNA达上千种。miRNA的发现为基因表达调控研究打开了新的窗口。目前研究者不仅关注miRNA在发育、分化、生长和代谢等诸多生物过程中的作用,而且开始进一步探寻其发挥作用的分子机理,以期重新描绘基因表达调控网络图。文章综述了miRNA对其靶基因的调控特点,介绍了miRNA自身调控研究的最新进展,从而有助于理解miRNA参与的基因表达调控网络的复杂性。