Role of long non-coding RNA in cells: Example of the <i>H</i>19/<i>IGF</i>2 locus

In the past decade, studies of non-coding RNAs increase. Non-coding RNAs are divided in two classes: small and long non-coding RNA. It was shown that long non-coding RNAs regulate expression of 70% of genes. Long non-coding RNAs are involved in several cellular processes like epigenetic regulation, dosage compensation, alternative splicing and stem cells maintenance for example. Misregulations of their expression induce diseases such as developmental syndrome or cancer. In this review, we describe some functions of long non-coding RNA in cells. Furthermore, we study the H19/IGF2 cluster: an imprinted genomic locus located on chromosome 11p15.5. Genomic imprinting allows gene expression from a single allele in a parent-origin-dependent manner. This cluster encode for the first long non-coding RNA identified: H19. In 1990, it was established that H19 functions as a riboregulator. Recently, it was shown that H19 is a precursor of microRNA (hsa-miR-675), and several news transcripts were identified at the H19/IGF2 locus. So, the complexity of this locus increasing, in this review, we summarize our current understanding about the H19/IGF2 cluster both in terms of transcription as well as in terms of functions in cells. We highlight the involvement of H19, its new antisense transcript 91H and its microRNA, in the regulation of IGF receptor function and in cell cycle progression.

Danhongqing formula alleviates cholestatic liver fibrosis by downregulating long non-coding RNA H19 derived from cholangiocytes and inhibiting hepatic stellate cell activation

Objective:This study explores the mechanism of action of Danhongqing formula(DHQ),a compoundbased Chinese medicine formula,in the treatment of cholestatic liver fibrosis.Methods:In vivo experiments were conducted using 8-week-old multidrug resistance protein 2 knockout(Mdr2-/-)mice as an animal model of cholestatic liver fibrosis.DHQ was administered orally for 8 weeks,and its impact on cholestatic liver fibrosis was evaluated by assessing liver function,liver histopathology,and the expression of liver fibrosis-related proteins.Real-time polymerase chain reaction,Western blot,immunohistochemistry and other methods were used to observe the effects of DHQ on long non-coding RNA H19(H19)and signal transducer and activator of transcription 3(STAT3)phosphorylation in the liver tissue of Mdr2-/-mice.In addition,cholangiocytes and hepatic stellate cells(HSCs)were cultured in vitro to measure the effects of bile acids on cholangiocyte injury and H19 expression.Cholangiocytes overexpressing H19 were constructed,and a conditioned medium containing H19 was collected to measure its effects on STAT3 protein expression and cell activation.The intervention effect of DHQ on these processes was also investigated.HSCs overexpressing H19 were constructed to measure the impact of H19 on cell activation and assess the intervention effect of DHQ.Results:DHQ alleviated liver injury,ductular reaction,and fibrosis in Mdr2-/-mice,and inhibited H19expression,STAT3 expression and STAT3 phosphorylation.This formula also reduced hydrophobic bile acid-induced cholangiocyte injury and the upregulation of H19,inhibited the activation of HSCs induced by cholangiocyte-derived conditioned medium,and decreased the expression of activation markers in HSCs.The overexpression of H19 in a human HSC line confirmed that H19 promoted STAT3 phosphorylation and HSC activation,and DHQ was able to successfully inhibit these effects.Conclusion:DHQ effectively alleviated spontaneous cholestatic liver fibrosis in Mdr2-/-mice by inhibiting H19 upregulation in cholangiocytes and preventing the inhibition of STAT3 phosphorylation in HSC,thereby suppressing cell activation.

Exosome-transported IncRNA H19 regulates insulin-like growth factor-1 via the H19/let-7a/insulin-like growth factor-1 receptor axis in ischemic stroke

LncRNA(long non-coding RNA) H19 is a transcript of the H19 gene that is expressed during embryogenesis.We previously discove red a role for circular lncRNA H19 in the onset and prognosis of cerebral ischemic stroke.In this study,we used serum from patients with ischemic stroke,and mouse and cell culture models to elucidate the roles of plasma and neuronal exosomes in the regulatory effect of lncRNA H19 on insulin-like growth factor-1 and its mechanism in ischemic stroke,using western blotting,quantitative real-time polymerase chain reaction,and enzyme-linked immunosorbent assays.Plasma exosomal IncRNA H19 was negatively associated with blood levels of insulin-like growth factor-1 in samples from patients with cerebral ischemic stroke.In a mouse model,levels of exosomal IncRNA H19 were positively correlated with plasma and cerebral lncRNA H19.In a cell co-culture model,we confirmed that IncRNA H19 was transported from neuro ns to astrocytes by exosomes to induce downregulation of insulin-like growth factor-1 through the H19/let-7 a/insulin-like growth factor-1 receptor axis.This study provides the first evidence for the transpo rtation of IncRNA H19 by exosomes and the relationship between IncRNA H19 and insulinlike growth factor-1.

类风湿关节炎患者血清长链非编码RNA HOTAIR、XIST和H19表达研究

目的探讨3种长链非编码RNA(lncRNA) HOTAIR、XIST和H19在类风湿关节炎(RA)、系统性红斑狼疮(SLE)和健康人对照组血清中的差异表达。方法收取50例RA疾病组、50例SLE疾病对照组和60例健康人对照组血清,共160例血清标本,提取血清总RNA,利用RT-qPCR方法分析HOTAIR、XIST和H19 3种lncRNA表达情况。用Spearman相关性分析探讨RA患者疾病活动指数(DAS28)与HOTAIR表达量的相关性。结果 RA组与健康人对照组和SLE疾病对照组相比,血清HOTAIR表达量显著增加(P<0.01),XIST在RA和对照组之间表达量差异无统计学意义; RA患者血清中HOTAIR表达值与DAS28评分呈正相关(R^2=0.27,P=0.002),且DAS28评分≥5.1的疾病高度活动组的HOTAIR表达值显著高于3.2<DAS28评分<5.1的疾病活动组(P<0.01);血清HOTAIR表达量与血清C反应蛋白(CRP)存在正相关关系(R^2=0.192,P=0.002)。结论LncRNA HOTAIR在RA患者血清中的表达量显著性升高且与DAS28评分呈显著正相关关系,血清中HOTAIR有可能成为诊断RA的潜在生物标志物。

The long non-coding RNA DANA2 positively regulates drought tolerance by recruitingERF84 to promote JMJ29-mediated histone demethylation

Tens of thousands of long non-coding RNAs have been uncovered in plants,but few of them have been comprehensively studied for their biological function and molecular mechanism of their mode of action.Here,we show that the Arabidopsis long non-coding RNA DANA2 interacts with an AP2/ERF transcription factor ERF84 in the cell nucleus and then affects the transcription of JMJ29 that encodes a Jumonji C domain-containing histone H3K9 demethylase.Both RNA sequencing(RNA-seq)and genetic analyses demonstrate that DANA2 positively regulates drought stress responses through JMJ29.JMJ29 positively regulates the expression of ERF15 and GOLS2 by modulation of H3K9me2 demethylation.Accordingly,mutation of JMJ29 causes decreased ERF15 and GOLS2 expression,resulting in impaired drought tolerance,in agreement with drought-sensitive phenotypes of dana2 and erf84 mutants.Taken together,these results demonstrate that DANA2 is a positive regulator of drought response and works jointly with the transcriptional activator ERF84 to modulate JMJ29 expression in plant response to drought.

H19基因的单核苷酸多态性与猪生长性状的相关分析及其时空表达

本试验为了了解H19基因在猪骨骼肌生长发育过程中的作用,首先采用实时荧光定量PCR的技术检测了H19的组织分布以及在骨骼肌生长发育中的动态表达。然后通过混合池测序检测了H19外显子和内含子区的单核苷酸多态位点(SNP),利用质谱在大白猪群体中进行SNPs位点基因型鉴定,并进行标记性状关联分析。H19基因在大白猪的心、肝、脾、肺、肾、小肠、胃、腿肌、背肌中均有表达,且在骨骼肌(腿肌、背肌)和肾中高表达。在骨骼肌发育中,H19主要是在胚胎期和出生后40d之前有较高表达量,并且在胚胎期105d达到最大值。对7个SNPs位点进行相关性分析,结果显示,RS15位点与达100kg体重的校正日龄显著相关(P=0.046 2<0.05),RS20位点与100kg的校正眼肌面积显著相关(P=0.009 5<0.01)。RS15与RS16紧密连锁,其单倍型与校正背膘厚显著相关(P=0.049 8<0.05);RS17与RS18单倍型与达100kg的校正眼肌面积显著相关(P=0.037 1<0.05)。结果表明H19基因参与猪骨骼肌发育调控,是猪产肉性状的候选基因。

Role of circulating long non-coding RNA for the improvement of the predictive ability of the CHA_(2)DS_(2)-VASc score in patients with atrial fibrillation

Background:The CHA_(2)DS_(2)-VASc score was initially applied to stratify stroke risk in patients with atrial fibrillation(AF)and was found to be effective in predicting all-cause mortality outcomes.To date,it is still unclear whether circulating long non-coding RNAs(lncRNAs)as emerging biomarkers,can improve the predictive power of the CHA_(2)DS_(2)-VASc score in stroke and all-cause mortality.Methods:Candidate lncRNAs were screened by searching the literature and analyzing previous RNA sequencing results.After preliminary verification in 29 patients with AF,the final selected lncRNAs were evaluated by Cox proportional hazards regression in 192 patients to determine whether their relative expression levels were associated with stroke and all-cause mortality.The c-statistic,net reclassification improvement(NRI),and integrated discrimination improvement of the patients were calculated to evaluate the discrimination and reclassification power for stroke and all-cause mortality when adding lncRNA expression levels to the CHA_(2)DS_(2)-VASc score model.Results:Five plasma lncRNAs associated with stroke and all-cause mortality in AF patients were selected in our screening process.Patients with elevated H19 levels were found to have a higher risk of stroke(hazard ratio[HR]3.264,95% confidence interval[CI]:1.364–7.813,P=0.008).Adding the H19 expression level to the CHA_(2)DS_(2)-VASc score significantly improved the discrimination and reclassification power of the CHA_(2)DS_(2)-VASc score for stroke in AF patients.In addition,the H19 level showed a marginally significant association with all-cause mortality(HR 2.263,95%CI:0.889–5.760,P=0.087),although it appeared to have no significant improvement for the CHA_(2)DS_(2)-VASc model for predicting all-cause mortality.Conclusions:Plasma expression of H19 was associated with stroke risk in AF patients and improved the discriminatory power of the CHA_(2)DS_(2)-VASc score.Therefore,lncRNA H19 served as an emerging non-invasive biomarker for stroke risk prediction in patients with AF.

长链非编码RNA AC023794.4-201在喉鳞状细胞癌中的表达及临床意义

喉癌是头颈部最常见的恶性肿瘤之一,其中85%～95%为鳞状细胞癌（laryngeal squamous cell carcinoma,LSCC）[1]。据报道早期LSCC患者的生存率远高于晚期患者[2]。研究发现,长链非编码RNA（long non-coding RNA,lncRNA）参与调控头颈部肿瘤细胞的增殖、分化、迁移和侵袭等,发挥抑癌基因或癌基因的功能[3～5]。

H19 recruited N^(6)-methyladenosine(m^(6)A)reader YTHDF1 to promote SCARB1 translation and facilitate angiogenesis in gastric cancer

Background:Angiogenesis is described as a complex process in which new microvessels sprout from endothelial cells of existing vasculature.This study aimed to determine whether long non-coding RNA(lncRNA)H19 induced the angiogenesis of gastric cancer(GC)and its possible mechanism.Methods:Gene expression level was determined by quantitative real-time polymerase chain reaction and western blotting.Cell counting kit-8,transwell,5-Ethynyl-2′-deoxyuridine(EdU),colony formation assay,and human umbilical vein endothelial cells(HUVECs)angiogenesis assay as well as Matrigel plug assay were conducted to study the proliferation,migration,and angiogenesis of GC in vitro and in vivo.The binding protein of H19 was found by RNA pull-down and RNA Immunoprecipitation(RIP).High-throughput sequencing was performed and next Gene Ontology(GO)as well as Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis was conducted to analyze the genes that are under H19 regulation.Methylated RIP(me-RIP)assay was used to investigate the sites and abundance among target mRNA.The transcription factor acted as upstream of H19 was determined through chromatin immunoprecipitation(ChIP)and luciferase assay.Results:In this study,we found that hypoxia-induced factor(HIF)-1a could bind to the promoter region of H19,leading to H19 overexpression.High expression of H19 was correlated with angiogenesis in GC,and H19 knocking down could inhibit cell proliferation,migration and angiogenesis.Mechanistically,the oncogenic role of H19 was achieved by binding with the N^(6)-methyladenosine(m^(6)A)reader YTH domain-containing family protein 1(YTHDF1),which could recognize the m^(6)A site on the 3′-untransated regions(3′-UTR)of scavenger receptor class B member 1(SCARB1)mRNA,resulting in over-translation of SCARB1 and thus promoting the proliferation,migration,and angiogenesis of GC cells.Conclusion:HIF-1a induced overexpression of H19 via binding with the promoter of H19,and H19 promoted GC cells proliferation,migration and angiogenesis through YTHDF1/SCARB1,which might be a beneficial target for antiangiogenic therapy for GC.

Use of blood-based biomarkers for early diagnosis and surveillance of colorectal cancer

Early screening for colorectal cancer(CRC) holds the key to combat and control the increasing global burden of CRC morbidity and mortality. However, the current available screening modalities are severely inadequate because of their high cost and cumbersome preparatory procedures that ultimately lead to a low participation rate. People simply do not like to have colonoscopies. It would be ideal, therefore, to develop an alternative modality based on blood biomarkers as the first line screening test. This will allow for the differentiation of the general population from high risk individuals. Colonoscopy would then become the secondary test, to further screen the high risk segment of the population. This will encourage participation and therefore help to reach the goal of early detection and thereby reduce the anticipated increasing global CRC incidence rate. A blood-based screening test is anappealing alternative as it is non-invasive and poses minimal risk to patients. It is easy to perform, can be repeated at shorter intervals, and therefore would likely lead to a much higher participation rate. This review surveys various blood-based test strategies currently under investigation, discusses the potency of what is available, and assesses how new technology may contribute to future test design.