microRNA在肝癌发生和发展中的作用及其机制

肝细胞肝癌(HCC)是我国常见的恶性肿瘤,其发生、发展是多因素、多基因和多步骤的复杂过程[1].miRNA(microRNA)是一类内源性非编码小分子RNA,可经序列特异性翻译抑制或mRNA裂解来调控基因表达,参与细胞发育、增殖、分化、凋亡等,约有1/3以上基因在转录后受其调控[2].新近研究结果表明,多种miRNA通过调节其靶基因参与HCC的细胞生物程序调控,间接发挥癌基因和抑癌基因的功能[3].了解miRNA的调控机制,可为肝细胞恶性转化及HCC的诊治提供理论依据.本文综述了miRNA在肝癌发生、发展中作用与机制的研究进展.     

非编码RNA与消化系统疾病的关系

近年来随着对微小RNA及小干扰RNA等的深入研究,人们逐渐认识到非编码RNA是一大类重要的基因调控因子,并在许多疾病的诊断、治疗、预后中起独特的作用。本文总结了近年来非编码RNA（ncRNA）在消化系统疾病的研究进展,探讨值得关注的研究方向。     

微小RNA在肝胆胰疾病中作用的研究进展

MircoRNA（miRNA）是一类非编码的小分子RNA,主要通过与目标mRNA互补配对,调控靶基因的表达或翻译,对细胞凋亡、增殖、细胞周期及细胞分化发育起调控作用。许多研究发现譬如miR-199a、miR-122、miRNA-335、miR-375等与肝胆胰疾病密切相关,而通过生物信息学与分子细胞生物学的手段鉴定它们的靶基因,也是目前的研究热点,本文就其与肝胆疾病的发生发展之间的关系作一综述。     

Tolerance versus immune response — MicroRNAs as important elements in the regulation of the HLA-G gene expression

HLA-G is a class Ib HLA which has gained much attention due to its multiple functions on the immune system. HLA-G exerts several immunomodulatory effects, being beneficially implicated in embryo implantation and fetal survival but, conversely, being potentially detrimental in tumors and viral infections. Such a two-edged sword behavior suggest that HLA-G expression is under tight regulation. However, to date, little is known about the regulation of this gene and previous works have been unable to well correlate HLA-G regulation at the mRNA level with the polymorphic variants at the genomic level. Here we present the hypothesis that an element, which was until now neglected, might play a role in HLA-G expression regulation: MicroRNAs might participate in the regulation of the HLA-G gene expression through a putative microRNA binding site at its 3′ UTR region. Inside the 20 nt region of this microRNA binding site lies a C/G polymorphism, which was shown to be responsible for differential microRNA binding affinity and translation suppression. The role of microRNA binding on the regulation of HLA-G gene expression (and therefore on tolerance versus immune response) can be easily tested through relatively simple steps: Confirming the expression of those three complementary microRNAs in human cells which express HLA-G, followed by examination of the correlation between HLA-G mRNA and protein production controlling for HLA-G genotypes and microRNA levels; finally, selective inhibition of microRNA activity with anti-sense oligos restoring HLA-G production would access microRNA influence on HLA-G expression which, if confirmed, might help in the development of strategies to the management of several conditions in which HLA-G is involved, including pregnancy complications, transplantation, and cancer.     

糖尿病肾病早期miRNAs表达谱分析

目的：探讨mi RNAs在糖尿病肾病（DN）早期的表达谱的改变,从而为其在DN发病机制中的研究提供有力的平台。方法：腹腔单剂注射链脲佐菌素（streptozotocin,STZ,150 mg/kg）建立小鼠糖尿病模型,检测对照组和糖尿病小鼠尿白蛋白排泄率,采用PAS染色观察肾脏组织学的改变;MicroRNAs微阵列分析采用单通道Cy5荧光标记法,分析对照组和糖尿病mi RNAs表达谱,利用GO分析对差异表达mi RNAs进行靶通道测定。结果：糖尿病组白蛋白排泄率显著高于对照组（P〈0.05）;PAS染色提示糖尿病组小鼠肾小球内大量细胞外基质积聚,系膜区明显增宽,符合DN早期的病理改变。糖尿病组共检测出128个mi RNAs,其中显著上调者分别mi R-34a,mi R-214,mi R-2132;显著下调者为mi R-2143,mi R-1970,mi R-703;以上差异有统计学意义mi RNAs参与细胞周期、细胞黏附、凋亡、小G蛋白介导的细胞信号传导的调控。结论：DN早期mi RNAs表达谱发生差异有统计学意义,微阵列技术为DN发病机制的研究提供了全新的研究策略。     

MiRNA profile in esophageal squamous cell carcinoma: downregulation of miR-143 and miR-145

AIM:To investigate the expression profile of miRNA in esophageal squamous cell carcinoma(ESCC).METHODS:The expression profile of miRNA in ESCC tissues was analyzed by miRNA microarray.The expression levels of miR-143 and miR-145 in 86 ESCC patients were determined by real-time polymerase chain reaction(PCR) using TaqMan assay.The mobility effect was estimated by wound-healing using esophageal carcinoma cells transfected with miRNA expression plasmids.RESULTS:A set of miRNAs was found to be deregulated in th...     

Helicobacter pylori-induced inflammation and epigenetic changes during gastric carcinogenesis

The sequence of events associated with the development of gastric cancer has been described as “the gastric precancerous cascade”. This cascade is a dynamic process that includes lesions, such as atrophic gastritis, intestinal metaplasia and dysplasia. According to this model, Helicobacter pylori (H. pylori) infection targets the normal gastric mucosa causing non-atrophic gastritis, an initiating lesion that can be cured by clearing H. pylori with antibiotics or that may then linger in the case of chronic infection and progress to atrophic gastritis. The presence of virulence factors in the infecting H. pylori drives the carcinogenesis process. Independent epidemiological and animal studies have confirmed the sequential progression of these precancerous lesions. Particularly long-term follow-up studies estimated a risk of 0.1% for atrophic gastritis/intestinal metaplasia and 6% in case of dysplasia for the long-term development of gastric cancer. With this in mind, a better understanding of the genetic and epigenetic changes associated with progression of the cascade is critical in determining the risk of gastric cancer associated with H. pylori infection. In this review, we will summarize some of the most relevant mechanisms and focus predominantly but not exclusively on the discussion of gene promoter methylation and miRNAs in this context.     

MicroRNA Expression Analysis in Patients with Primary Myelofibrosis,Polycythemia vera and Essential Thrombocythemia

MicroRNAs (miRNA) are small non-coding RNA molecules that play critical roles in cell differentiation, proliferation and apoptosis and thus regulate haematopoietic stem cells and committed progenitor cells. We analyzed expressions of miRNAs associated with hematopoietic transformation of myeloid, erythroid and megakaryocytic progenitor cells during haematopoiesis (mir155, mir181a, mir221, mir222, mir223, mir451), in patients with primary myelofibrosis (PMF) (n = 22), polycythemia vera (PV) (n = 33), essential thrombocythemia (ET) (n = 49) and in healthy controls (n = 40) by quantitate/real time polymerase chain reaction. RT-PCR testing was negative for BCR–ABL1 fusion gene in all the patients. Mir155 was expressed in higher levels in all 3 disorders (p < 0.05). Mir221 was higher especially in ET and PMF group (p < 0.05). Mir222 expression was lower in PV patients (p < 0.05) and higher in ET and PMF patients compared to control group. Mir223 expression was higher in ET and PMF group than control group (p > 0.05). Mir451 levels were lower in all three groups compared to control group (p < 0.05). There was no difference in expression levels of mir181a between groups. JAK2V617F positivity, co-morbidities, drugs, and gender did not affect miRNA expressions. This study holds promise for the future application of these molecules for differential diagnosis and as therapeutic targets in Philadelphia chromosome negative myeloproliferative neoplasms.