MicroRNAs and cardiovascular diseases

MicroRNAs (miRNAs) are a class of small noncoding RNAs that have gained status as important regulators of gene expression. Recent studies have demonstrated that miRNAs are aberrantly expressed in the cardiovascular system under some pathological conditions. Gain- and loss-of-function studies using in vitro and in vivo models have revealed distinct roles for specific miRNAs in cardiovascular development and physiological function. The implications of miRNAs in cardiovascular disease have recently been recognized, representing the most rapidly evolving research field. In the present minireview, the current relevant findings on the role of miRNAs in cardiac diseases are updated and the target genes of these miRNAs are summarized.     

MicroRNAs in skeletal and cardiac muscle development

MicroRNAs (miRNAs) are a recently discovered class of small non-coding RNAs, which are approximately 22 nucleotides in length. miRNAs negatively regulate gene expression by translational repression and target mRNA degradation. It has become clear that miRNAs are involved in many biological processes, including development, differentiation, proliferation, and apoptosis. Interestingly, many miRNAs are expressed in a tissue-specific manner and several miRNAs are specifically expressed in cardiac and skeletal muscles. In this review, we focus on those miRNAs that have been shown to be involved in muscle development. Compelling evidences have demonstrated that muscle miRNAs play an important role in the regulation of muscle proliferation and differentiation processes. However, it appears that miRNAs are not essential for early myogenesis and muscle specification. Importantly, dysregulation of miRNAs has been linked to muscle-related diseases, such as cardiac hypertrophy. A mutation resulting in a gain-of-function miRNA target site in the myostatin gene leads to down regulation of the targeted protein in Texel sheep. miRNAs therefore are a new class of regulators of muscle biology and they might become novel therapeutic targets in muscle-related human diseases.     

MicroRNAs: a new class of regulatory genes affecting metabolism

MicroRNAs (miRNAs) are short noncoding RNAs that regulate gene expression by binding to target mRNAs, which leads to reduced protein synthesis and sometimes decreased steady-state mRNA levels. Although hundreds of miRNAs have been identified, much less is known about their biological function. Several studies have provided evidence that miRNAs affect pathways that are fundamental for metabolic control in higher organisms such as adipocyte and skeletal muscle differentiation. Furthermore, some miRNAs have been implicated in lipid, amino acid, and glucose homeostasis. These studies open the possibility that miRNAs may contribute to common metabolic diseases and point to novel therapeutic opportunities based on targeting of miRNAs.     

植物激素相关microRNA研究进展

microRNA（miRNA）是22nt左右的非编码RNA,主要在转录后水平调节基因的活性。miRNA通过与靶基因的互补位点结合从而降解靶基因mRNA或抑制其翻译。近年的研究发现,miRNA在植物生长发育中发挥着重要的调控作用。目前已知一些miRNA参与植物激素信号途径的切入点,这为我们了解miRNA和植物激素在植物发育中的作用提供了新思路。本文综述了miRNA参与植物激素信号应答及生物合成的研究进展,并对一些miINA在植物激素信号应答中可能的作用进行了讨论。     

MicroRNAs Involved in Skeletal Muscle Differentiation

MicroRNAs (miRNAs) negatively regulate gene expression by promoting degradation of target mRNAs or inhibiting their translation. Previous studies have expanded our understanding that miRNAs play an important role in myogenesis and have a big impact on muscle mass, muscle fiber type and muscle-related diseases. The muscle-specific miRNAs, miR-206, miR-1 and miR-133, are among the most studied and best characterized miRNAs in skeletal muscle differentiation. They have a profound influence on multiple muscle differ-entiation processes, such as alternative splicing, DNA synthesis, and cell apoptosis. Many non-muscle-specific miRNAs are also required for the differentiation of muscle through interaction with myogenic factors. Studying the regulatory mechanisms of these miRNAs in muscle differentiation will extend our knowledge of miRNAs in muscle biology and will improve our understanding of the myogenesis regulation.     

microRNAs and the mammary gland: A new understanding of gene expression

MicroRNAs (miRNAs) have been identified in cells as well as in exosomes in biological fluids such as milk. In mammary gland, most of the miRNAs studied have functions related to immunity and show alterations in their pattern of expression during lactation. In mastitis, the inflammatory response caused by Streptococcus uberis alters the expression of miRNAs that may regulate the innate immune system. These small RNAs are stable at room temperature and are resistant to repeated freeze/thaw cycles, acidic conditions and degradation by RNAse, making them resistant to industrial procedures. These properties mean that miRNAs could have multiple applications in veterinary medicine and biotechnology. Indeed, lactoglobulin-free milk has been produced in transgenic cows expressing specific miRNAs. Although plant and animal miRNAs have undergone independent evolutionary adaptation recent studies have demonstrated a cross-kingdom passage in which rice miRNA was isolated from human serum. This finding raises questions about the possible effect that miRNAs present in foods consumed by humans could have on human gene regulation. Further studies are needed before applying miRNA biotechnology to the milk industry. New discoveries and a greater knowledge of gene expression will lead to a better understanding of the role of miRNAs in physiology, nutrition and evolution.     

常见肝炎病毒感染性疾病相关miRNA功能研究进展

病毒感染引发的疾病一直威胁着人类健康。Mi RNA是真核生物表达的一类重要的小分子RNA,可特异性的调节基因与蛋白的表达。mi RNA的研究为病毒性疾病的发生发展提供了新思路,为目前热点研究领域。随着mi RNA的研究深入,一些病毒感染中相关mi RNA的功能也被相继报道,如有些mi RNA具有抑制病毒感染宿主细胞的功能,有些mi RNA则可促进病毒在宿主细胞中的复制,有些mi RNA却参与病毒相关疾病的发生,还有些mi RNA则可作为病毒感染性疾病的特异性生物标志物。本文主要以两种常见肝炎病毒:HBV、HCV为例来系统阐述mi RNA在病毒感染中的相关功能。     

Identification of Glycine Max MicroRNAs in response to phosphorus deficiency

MicroRNAs (miRNAs) are endogenous small RNAs regulating plant development and stress responses. In addition, phosphorus (P) is an important macronutrient for plant growth and development. More than two hundred miRNAs have been identified in Glycine Max and a few of miRNAs have been shown to respond to P deficiency, however, whether there are other miRNAs involved in P deficiency response is largely unknown. In this study, we used high-throughput small RNA sequencing and whole-genome-wide mining to identify the potential miRNAs in response to P deficiency. After sequencing, we deduced 183 known, 99 conserved and 126 novel miRNAs in Glycine Max. Among them, in response to P deficiency, the expressions of 27 known, 16 conserved and 12 novel miRNAs showed significant changes in roots, whereas the expressions of 34 known, 14 conserved and 7 novel miRNAs were significantly different in shoots. Furthermore, we validated the predicated novel miRNAs and found that three miRNAs in roots and five miRNAs in shoots responded to P deficiency. Some miRNAs were P-induced whereas some were P-suppressed. Together these results indicated that the miRNAs identified might play important roles in regulating P signaling pathway.     

Macro effects of microRNAs in plants

MicroRNAs (miRNAs) are 20- to 22-nucleotide fragments that regulate expression of mRNAs that have complementary sequences. They are numerous and widespread among eukaryotes, being conserved throughout evolution. The few miRNAs that have been fully characterized were found in Caenorhabditis elegans and are required for development. Recently, a study of miRNAs isolated from Arabidopsis showed that here also developmental genes are putative regulatory targets. A role for miRNAs have in plant development is supported by the developmental phenotypes of mutations in the genes required for miRNA processing.     

Critical Roles of microRNAs in the Pathogenesis of Fatty Liver: New Advances,Challenges, and Potential Directions

In this review, we summarize the current understanding of microRNA (miRNA)-mediated modulation of the gene expression in the fatty liver as well as related signaling pathways. Because of the breadth and diversity of miRNAs, miRNAs may have a very wide variety of biological functions, and much evidence has confirmed that miRNAs are involved in the pathogenesis of fatty liver. In the pathophysiological mechanism of fatty liver, miRNAs may be regulated by upstream regulators, and have their own regulatory targets. miRNAs display important roles in the pathological mechanisms of alcoholic liver disease and non-alcoholic fatty liver disease. At present, most of the miRNA studies are focused on cell and tissue levels, and in vivo studies will help us elucidate the regulation of miRNAs and help us evaluate the potential of miRNAs as diagnostic markers and therapeutic targets. Furthermore, there is evidence that miRNAs are involved in the mechanism of natural medicine treatment in fatty liver. Given the important roles of miRNAs in the pathogenesis of fatty liver, we predict that studies of miRNAs in the pathogenesis of fatty liver will contribute to the elucidation of fatty liver pathology and the treatment of fatty liver patients.     

Modulatory roles of microRNAs in the regulation of different signalling pathways in large bowel cancer stem cells

There are emerging data to suggest that microRNAs (miRNAs) have significant roles in regulating the function of normal cells and cancer stem cells (CSCs). This review aims to analyse the roles of miRNAs in the regulation of colon CSCs through their interaction with various signalling pathways. Studies showed a large number of miRNAs that are reported to be deregulated in colon CSCs. However, few of the studies available were able to outline the function of miRNAs in colon CSCs and uncover their signalling pathways. From those miRNAs, which are better described, miR‐21 followed by miR‐34, miR‐200 and miR‐215 are the most reported miRNAs to have roles in colon CSC regulation. In particular, miRNAs have been reported to regulate the stemness features of colon CSCs mainly via Wnt/B‐catenin and Notch signalling pathways. Additionally, miRNAs have been reported to act on processes involving CSCs through cell cycle regulation genes and epithelial–mesenchymal transition. The relative paucity of data available on the significance of miRNAs in CSCs means that new studies will be of great importance to determine their roles and to identify the signalling pathways through which they operate. Such studies may in future guide further research to target these genes for more effective cancer treatment. miRNAs were shown to regulate the function of cancer stem cells in large bowel cancer by targeting a few key signalling pathways in cells.     

动物中microRNA 的保守性和进化历程

microRNA 是一类长度约为22 个核苷酸的内源性非编码单链RNA, 在后生动物中普遍存在, 在转录后过程调控基因表达. miRNA 在个体发育过程中发挥着各种功能, 如发育时序调控和细胞分化、神经发育等. miRNA 在各种后生动物中具有保守性, 而且多个关键类群的出现皆伴随着大量新miRNA 的产生, 这些现象都表明miRNA 与动物的系统发生密切相关. 本文从miRNA 的产生和作用机制、在后生动物中的分布格局及其在个体发育中的调控功能3 个方面论述了miRNA 的保守性, 并结合miRNA 的发生和发展历程, 探讨了miRNA 在动物进化中起到的重要作用.