Originating but free from chromosomal DNA,extrachromosomal circular DNAs(eccDNAs)are organized in circular form and have long been found in unicellular and multicellular eukaryotes.Their biogenesis and function are po...Originating but free from chromosomal DNA,extrachromosomal circular DNAs(eccDNAs)are organized in circular form and have long been found in unicellular and multicellular eukaryotes.Their biogenesis and function are poorly understood as they are characterized by sequence homology with linear DNA,for which few detection methods are available.Recent advances in high-throughput sequencing technologies have revealed that eccDNAs play crucial roles in tumor formation,evolution,and drug resistance as well as aging,genomic diversity,and other biological processes,bringing it back to the research hotspot.Several mechanisms of eccDNA formation have been proposed,including the breakage-fusion-bridge(BFB)and translocation-deletion-amplification models.Gynecologic tumors and disorders of embryonic and fetal development are major threats to human reproductive health.The roles of eccDNAs in these pathological processes have been partially elucidated since the first discovery of eccDNA in pig sperm and the double minutes in ovarian cancer ascites.The present review summarized the research history,biogenesis,and currently available detection and analytical methods for eccDNAs and clarified their functions in gynecologic tumors and reproduction.We also proposed the application of eccDNAs as drug targets and liquid biopsy markers for prenatal diagnosis and the early detection,prognosis,and treatment of gynecologic tumors.This review lays theoretical foundations for future investigations into the complex regulatory networks of eccDNAs in vital physiological and pathological processes.展开更多
The silk gland cells of silkworm are special cells which only replicate DNA in the nucleus without cell division throughout the larval stage. The extrachromosomal circular DNAs (eccDNAs) have not yet been reported in ...The silk gland cells of silkworm are special cells which only replicate DNA in the nucleus without cell division throughout the larval stage. The extrachromosomal circular DNAs (eccDNAs) have not yet been reported in the silk gland of silkworms. Herein, we have explored the characterization of eccDNAs in the posterior silk gland of silkworms. A total of 35 346 eccDNAs were identified with sizes ranging from 30 to 13 569 549 bp. Motif analysis revealed that dual direct repeats are flanking the 5′ and 3′ breaking points of eccDNA. The sequences exceeding 1 kb length in eccDNAs present palindromic sequence characteristics flanking the 5′ and 3′ breaking points of the eccDNA. These motifs might support possible models for eccDNA generation. Genomic annotation of the eccDNA population revealed that most eccDNAs (58.6%) were derived from intergenic regions, whereas full or partial genes were carried by 41.4% of eccDNAs. It was found that silk protein genes fib-H, fib-L, and P25, as well as the transcription factors SGF and sage, which play an important regulatory role in silk protein synthesis, could be carried by eccDNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses showed that the genes carried by eccDNAs were mainly associated with the development and metabolism-related signaling pathways. Moreover, it was found that eccDNAfib-L could promote the transcription of fib-L gene. Overall, the results of the present study not only provide a novel perspective on the mechanism of silk gland development and silk protein synthesis but also complement previously reported genome-scale eccDNA data supporting that eccDNAs are common in eukaryotes.展开更多
BACKGROUND Minimally invasive or noninvasive,sensitive and accurate detection of colorectal cancer(CRC)is urgently needed in clinical practice.AIM To identify a noninvasive,sensitive and accurate circular free DNA mar...BACKGROUND Minimally invasive or noninvasive,sensitive and accurate detection of colorectal cancer(CRC)is urgently needed in clinical practice.AIM To identify a noninvasive,sensitive and accurate circular free DNA marker detected by digital polymerase chain reaction(dPCR)for the early diagnosis of clinical CRC.METHODS A total of 195 healthy control(HC)individuals and 101 CRC patients(38 in the early CRC group and 63 in the advanced CRC group)were enrolled to establish the diagnostic model.In addition,100 HC individuals and 62 patients with CRC(30 early CRC and 32 advanced CRC groups)were included separately to validate the model.CAMK1D was dPCR.Binary logistic regression analysis was used to establish a diagnostic model including CAMK1D and CEA.RESULTS To differentiate between the 195 HCs and 101 CRC patients(38 early CRC and 63 advanced CRC patients),the common biomarkers CEA and CAMK1D were used alone or in combination to evaluate their diagnostic value.The area under the curves(AUCs)of CEA and CAMK1D were 0.773(0.711,0.834)and 0.935(0.907,0.964),respectively.When CEA and CAMK1D were analyzed together,the AUC was 0.964(0.945,0.982).In differentiating between the HC and early CRC groups,the AUC was 0.978(0.960,0.995),and the sensitivity and specificity were 88.90%and 90.80%,respectively.In differentiating between the HC and advanced CRC groups,the AUC was 0.956(0.930,0.981),and the sensitivity and specificity were 81.30%and 95.90%,respectively.After building the diagnostic model containing CEA and CAMK1D,the AUC of the CEA and CAMK1D joint model was 0.906(0.858,0.954)for the validation group.In differentiating between the HC and early CRC groups,the AUC was 0.909(0.844,0.973),and the sensitivity and specificity were 93.00%and 83.30%,respectively.In differentiating between the HC and advanced CRC groups,the AUC was 0.904(0.849,0.959),and the sensitivity and specificity were 93.00%and 75.00%,respectively.CONCLUSION We built a diagnostic model including CEA and CAMK1D for differentiating between HC individuals and CRC patients.Compared with the common biomarker CEA alone,the diagnostic model exhibited significant improvement.展开更多
目的探讨丙型肝炎病毒NS5A反式调节蛋白9(hepatitis C virus NS5Atransactivated protein 9,NS5ATP9)在乙型肝炎病毒(hepatitis B virus,HBV)共价闭合环状DNA(covalently closed circular DNA,cccDNA)形成与转录中的作用机制。方法利用...目的探讨丙型肝炎病毒NS5A反式调节蛋白9(hepatitis C virus NS5Atransactivated protein 9,NS5ATP9)在乙型肝炎病毒(hepatitis B virus,HBV)共价闭合环状DNA(covalently closed circular DNA,cccDNA)形成与转录中的作用机制。方法利用1.3拷贝HBV表达质粒转染Huh7和HepG2细胞、整合有4拷贝HBV基因组的HepG2.2.15细胞、在诱导型四环素启动子控制下表达HBV的HepAD38细胞构建NS5ATP9过表达或干扰的HBV细胞模型,收集样品和细胞上清液,提取RNA、HBV核心DNA(coreDNA)、cccDNA和蛋白,利用酶联免疫吸附试验、实时荧光定量聚合酶链反应(polymerase chain reaction,PCR)、Southern blot和Western blot技术检测HBV总RNA、前基因组RNA(pregenomic RNA,pgRNA)、乙型肝炎病毒s抗原(hepatitis B virus s antigene,HBsAg)、乙型肝炎病毒e抗原(hepatitis B virus e antigene,HBeAg)、松弛环状DNA(relax circular DNA,rcDNA)以及cccDNA水平。在HepG2细胞中转染乙型肝炎病毒x蛋白(hepatitis B virus x protein,HBx),通过免疫荧光成像及免疫共沉淀方法检测NS5ATP9与HBx的结合情况。双荧光素酶报告基因实验检测NS5ATP9对HBx启动子活性的影响。利用Huh7细胞转染HBV1.3及HBV稳定表达细胞株HepG2.2.15和HepAD38转染NS5ATP9过表达/干扰质粒,通过Western blot技术检测DDB1和SMC6的蛋白水平。结果在HBV病毒活跃的细胞中,NS5ATP9 mRNA水平[HepG2.2.15细胞:1.891±0.567比1.00±0.034,t=2.87,P=0.0351;HepAD38 tet+细胞:1.978±0.399比1.00±0.034,t=4.131,P=0.0091;HepAD38 tet-细胞:2.642±0.672比1.00±0.034,t=4.127,P=0.0091]和蛋白水平均显著增加。过表达NS5ATP9后可显著增加HBeAg[(5.402±0.327)S/COV比(2.68±0.552)S/COV,t=7.35,P=0.0018]、HBsAg[(2.846±0.185)S/COV比(1.512±0.221)S/COV,t=8.02,P=0.0013]、HBV pgRNA及rcDNA的表达水平,而干扰NS5ATP9后此增加作用消失[HBeAg:(2.029±0.09)S/COV比(3.733±0.445)S/COV,t=6.501,P=0.0029;HBsAg:(1.501±0.105)S/COV比(1.878±0.174)S/COV,t=3.216,P=0.0324)]。机制研究显示,NS5ATP9和HBx蛋白主要位于细胞核核仁内,并具有共定位信号,且NS5ATP9可显著提高HBx启动子(1071.06±79.44比488.47±40.12,t=13.09,P=0.00012)的转录活性。另外,过表达NS5ATP9可显著降低DDB1和SMC6的蛋白水平,而沉默NS5ATP9则可显著提高DDB1和SMC6的蛋白水平。结论HBV上调NS5ATP9的表达,形成HBV-NS5ATP9-HBV cccDNA-HBV的正反馈环路,NS5ATP9通过与HBx相互作用上调肝细胞中HBV cccDNA的形成与转录,进而促进慢性乙型肝炎的发生发展。展开更多
250 million people worldwide continue to be chronically infected with the virus.While patients may be treated with nucleoside/nucleotide analogues,this only suppresses HBV titre to sub-detection levels without elimina...250 million people worldwide continue to be chronically infected with the virus.While patients may be treated with nucleoside/nucleotide analogues,this only suppresses HBV titre to sub-detection levels without eliminating the persistent HBV covalently closed circular DNA(cccDNA)genome.As a result,HBV infection cannot be cured,and the virus reactivates when conditions are favorable.Interferons(IFNs)are cytokines known to induce powerful antiviral mechanisms that clear viruses from infected cells.They have been shown to induce cccDNA clearance,but their use in the treatment of HBV infection is limited as HBVtargeting immune cells are exhausted and HBV has evolved multiple mechanisms to evade and suppress IFN signalling.Thus,to fully utilize IFN-mediated intracellular mechanisms to effectively eliminate HBV,instead of direct IFN administration,novel strategies to sustain IFN-mediated anti-cccDNA and antiviral mechanisms need to be developed.This review will consolidate what is known about how IFNs act to achieve its intracellular antiviral effects and highlight the critical interferon-stimulated gene targets and effector mechanisms with potent anti-cccDNA functions.These include cccDNA degradation by APOBECs and cccDNA silencing and transcription repression by epigenetic modifications.In addition,the mechanisms that HBV employs to disrupt IFN signalling will be discussed.Drugs that have been developed or are in the pipeline for components of the IFN signalling pathway and HBV targets that detract IFN signalling mechanisms will also be identified and discussed for utility in the treatment of HBV infections.Together,these will provide useful insights into design strategies that specifically target cccDNA for the eradication of HBV.展开更多
Hepatitis B virus(HBV) infection is a major global health problem. Although current therapies, such as the use of nucleos(t)ide analogs, inhibit HBV replication efficiently, they do not eliminate covalently closed cir...Hepatitis B virus(HBV) infection is a major global health problem. Although current therapies, such as the use of nucleos(t)ide analogs, inhibit HBV replication efficiently, they do not eliminate covalently closed circular DNA(ccc DNA), which persists in hepatocyte nuclei. As HBV ccc DNA is a viral transcription template, novel therapeutic approaches to directly target HBV ccc DNA are necessary to completely eradicate persistent HBV infections. HBV ccc DNA levels in HBV-infected human liver cells are extremely low; thus, more reliable and simple measurement methods are needed to correctly monitor their levels during therapeutic treatment. Although reverse transcription-polymerase chain reaction or Southern blot procedures are currently used in research studies, these methods are not completely reliable and are also time-consuming and labor-intensive. Genome editing technologies, such as zinc finger nucleases, transcription activator-like effector nucleases, and the clustered regularly interspaced short palindromic repeats/Cas9(CRISPR/Cas9) system, which are designed to target specific DNA sequences, represent highly promising potential therapeutic tools. In particular, the CRISPR/Cas9 system is an easily customizable sequencespecific nuclease with high flexibility and may be the most feasible approach to target HBV ccc DNA. Further research to develop easier, safer, and more effective protocols should be pursued.展开更多
AIM:To evaluate the effects of antiviral agents and HBV genotypes on intrahepatic covalently closed circular DNA (ccc DNA) in HBeAg-positive chronic hepatitis B patients. METHODS:Seventy-one patients received lamivudi...AIM:To evaluate the effects of antiviral agents and HBV genotypes on intrahepatic covalently closed circular DNA (ccc DNA) in HBeAg-positive chronic hepatitis B patients. METHODS:Seventy-one patients received lamivudine (n = 35), or sequential therapy with lamivudine-interferon alpha 2b (IFN-α 2b, n = 24) for 48 wk, or IFN-α 2b (n = 12) for 24 wk. All subjects were followed up for 24 wk. Intrahepatic ccc DNA was measured quantitatively by PCR. HBV genotypes were analyzed by PCR-RFLP. RESULTS:Sequential lamivudine-INF-α therapy, lamivudine and INF-α monotherapy reduced ccc DNA of 1.7 log, 1.4 log and 0.8 log, respectively (P < 0.05). Seventeen out of the 71 patients developed HBeAg seroconversion, the reduction of ccc DNA in the HBeAg seroconversion patients was more significant than that in the HBeAg positive patients (3.0 log vs 1.6 log, P = 0.0407). Twenty-four weeks after antiviral therapy withdrawal, 16 patients had a sustained virological response, the baseline intrahepatic ccc DNA in the patients with a sustained virological response was significantly lower than that in the patients with virological rebound (4.6 log vs 5.4 log, P = 0.0472). HBV genotype C accounted for 85.9% (n = 61), and genotype B for 14.1% (n = 10), respectively, in the 71 patients. There was no significant difference in the change of ccc DNA level between HBV genotypes C and B (2.1 log vs 1.9 log). CONCLUSION:Forty-eight week sequential lamivudine-INF-α therapy and lamivudine monotherapy reduce ccc DNA more significantly than 24-wk INF-α monotherapy. Low baseline intrahepatic ccc DNA level may predict the long-term efficacy of antiviral treatment. HBV genotypes C and B have no obvious influence on ccc DNA load.展开更多
Chronic infection with hepatitis B virus(HBV)remains a major global health problem,especially in developing countries.It may lead to prolonged liver damage,fibrosis,cirrhosis,and hepatocellular carcinoma.Persistent ch...Chronic infection with hepatitis B virus(HBV)remains a major global health problem,especially in developing countries.It may lead to prolonged liver damage,fibrosis,cirrhosis,and hepatocellular carcinoma.Persistent chronic HBV infection is related to host immune response and the stability of the covalently closed circular DNA(cccDNA)in human hepatocytes.In addition to being essential for viral transcription and replication,cccDNA is also suspected to play a role in persistent HBV infections or hepatitis relapses since cccDNA is very stable in non-dividing human hepatocytes.Understanding the pathogenicity and oncogenicity of HBV components would be essential in the development of new diagnostic tools and treatment strategies.This review summarizes the role and molecular mechanisms of HBV cccDNA in hepatocyte transformation and hepatocarcinogenesis and current efforts to its detection and targeting.展开更多
BACKGROUND Colorectal cancer(CRC) is the third most common cancer worldwide, and it is the second leading cause of death from cancer in the world, accounting for approximately 9% of all cancer deaths. Early detection ...BACKGROUND Colorectal cancer(CRC) is the third most common cancer worldwide, and it is the second leading cause of death from cancer in the world, accounting for approximately 9% of all cancer deaths. Early detection of CRC is urgently needed in clinical practice.AIM To build a multi-parameter diagnostic model for early detection of CRC.METHODS Total 59 colorectal polyps(CRP) groups, and 101 CRC patients(38 early-stage CRC and 63 advanced CRC) for model establishment. In addition, 30 CRP groups,and 62 CRC patients(30 early-stage CRC and 32 advanced CRC) were separately included to validate the model. 51 commonly used clinical detection indicators and the 4 extrachromosomal circular DNA markers NDUFB7, CAMK1D, PIK3CD and PSEN2 that we screened earlier. Four multi-parameter joint analysis methods:binary logistic regression analysis, discriminant analysis, classification tree and neural network to establish a multi-parameter joint diagnosis model.RESULTS Neural network included carcinoembryonic antigen(CEA), ischemia-modified albumin(IMA),sialic acid(SA), PIK3CD and lipoprotein a(LPa) was chosen as the optimal multi-parameter combined auxiliary diagnosis model to distinguish CRP and CRC group, when it differentiated 59CRP and 101 CRC, its overall accuracy was 90.8%, its area under the curve(AUC) was 0.959(0.934,0.985), and the sensitivity and specificity were 91.5% and 82.2%, respectively. After validation,when distinguishing based on 30 CRP and 62 CRC patients, the AUC was 0.965(0.930-1.000), and its sensitivity and specificity were 66.1% and 70.0%. When distinguishing based on 30 CRP and 32early-stage CRC patients, the AUC was 0.960(0.916-1.000), with a sensitivity and specificity of 87.5% and 90.0%, distinguishing based on 30 CRP and 30 advanced CRC patients, the AUC was 0.970(0.936-1.000), with a sensitivity and specificity of 96.7% and 86.7%.CONCLUSION We built a multi-parameter neural network diagnostic model included CEA, IMA, SA, PIK3CD and LPa for early detection of CRC, compared to the conventional CEA, it showed significant improvement.展开更多
The availability of the plastid genome sequences is one of the bases for comparative,functional,and structural genomic studies of plastid-containing living organisms,in addition to the application
乙型肝炎是感染乙型肝炎病毒(hepatitis B virus,HBV)引起肝脏慢性炎症性改变为主要特征的一类传染病。长期慢性感染将导致肝纤维化、肝硬化、肝癌等终末期肝病的发生,严重危害人民群众的健康。慢性乙型肝炎病毒感染依然是全球公共卫生...乙型肝炎是感染乙型肝炎病毒(hepatitis B virus,HBV)引起肝脏慢性炎症性改变为主要特征的一类传染病。长期慢性感染将导致肝纤维化、肝硬化、肝癌等终末期肝病的发生,严重危害人民群众的健康。慢性乙型肝炎病毒感染依然是全球公共卫生健康问题之一。目前临床上使用的抗病毒治疗方案难以实现对乙型肝炎病毒的彻底清除,其根源在于被感染肝细胞核内持续存在具有稳定结构的共价闭合环状DNA(covalently closed circular DNA,cccDNA)。本文对乙型肝炎病毒共价闭合环状DNA清除的研究进展进行综述,旨在寻找清除cccDNA的途径及办法从而达到乙型肝炎病毒的彻底清除。展开更多
基金supported by the National Natural Science Foundation of China [Grant Nos.32170493,32170656]the National Clinical Research Center for Obstetrics and Gynecology (Peking University Third Hospital)[Grant No.BYSYSZKF2022005]the Clinical Medicine Plus X-Young Scholars Project,Peking University,the Fundamental Research Funds for the Central Universities (PKU2023LCXQ036)。
文摘Originating but free from chromosomal DNA,extrachromosomal circular DNAs(eccDNAs)are organized in circular form and have long been found in unicellular and multicellular eukaryotes.Their biogenesis and function are poorly understood as they are characterized by sequence homology with linear DNA,for which few detection methods are available.Recent advances in high-throughput sequencing technologies have revealed that eccDNAs play crucial roles in tumor formation,evolution,and drug resistance as well as aging,genomic diversity,and other biological processes,bringing it back to the research hotspot.Several mechanisms of eccDNA formation have been proposed,including the breakage-fusion-bridge(BFB)and translocation-deletion-amplification models.Gynecologic tumors and disorders of embryonic and fetal development are major threats to human reproductive health.The roles of eccDNAs in these pathological processes have been partially elucidated since the first discovery of eccDNA in pig sperm and the double minutes in ovarian cancer ascites.The present review summarized the research history,biogenesis,and currently available detection and analytical methods for eccDNAs and clarified their functions in gynecologic tumors and reproduction.We also proposed the application of eccDNAs as drug targets and liquid biopsy markers for prenatal diagnosis and the early detection,prognosis,and treatment of gynecologic tumors.This review lays theoretical foundations for future investigations into the complex regulatory networks of eccDNAs in vital physiological and pathological processes.
基金funded by National Key R&D Program of China(2019YFA0905200)the Natural Science Founda-tion of the Jiangsu Higher Education Institutions ofChina(22KJB23003)+2 种基金the National Natural Science Foundation of China(31872424,31972620,and 32072792)China Postdoctoral Science Foundation(2019M661937)Priority Academic Program of Development of Jiangsu Higher Education Institutions.
文摘The silk gland cells of silkworm are special cells which only replicate DNA in the nucleus without cell division throughout the larval stage. The extrachromosomal circular DNAs (eccDNAs) have not yet been reported in the silk gland of silkworms. Herein, we have explored the characterization of eccDNAs in the posterior silk gland of silkworms. A total of 35 346 eccDNAs were identified with sizes ranging from 30 to 13 569 549 bp. Motif analysis revealed that dual direct repeats are flanking the 5′ and 3′ breaking points of eccDNA. The sequences exceeding 1 kb length in eccDNAs present palindromic sequence characteristics flanking the 5′ and 3′ breaking points of the eccDNA. These motifs might support possible models for eccDNA generation. Genomic annotation of the eccDNA population revealed that most eccDNAs (58.6%) were derived from intergenic regions, whereas full or partial genes were carried by 41.4% of eccDNAs. It was found that silk protein genes fib-H, fib-L, and P25, as well as the transcription factors SGF and sage, which play an important regulatory role in silk protein synthesis, could be carried by eccDNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses showed that the genes carried by eccDNAs were mainly associated with the development and metabolism-related signaling pathways. Moreover, it was found that eccDNAfib-L could promote the transcription of fib-L gene. Overall, the results of the present study not only provide a novel perspective on the mechanism of silk gland development and silk protein synthesis but also complement previously reported genome-scale eccDNA data supporting that eccDNAs are common in eukaryotes.
基金Supported by the Henan Medical Science and Technology Research Program,No.LHGJ20210045.
文摘BACKGROUND Minimally invasive or noninvasive,sensitive and accurate detection of colorectal cancer(CRC)is urgently needed in clinical practice.AIM To identify a noninvasive,sensitive and accurate circular free DNA marker detected by digital polymerase chain reaction(dPCR)for the early diagnosis of clinical CRC.METHODS A total of 195 healthy control(HC)individuals and 101 CRC patients(38 in the early CRC group and 63 in the advanced CRC group)were enrolled to establish the diagnostic model.In addition,100 HC individuals and 62 patients with CRC(30 early CRC and 32 advanced CRC groups)were included separately to validate the model.CAMK1D was dPCR.Binary logistic regression analysis was used to establish a diagnostic model including CAMK1D and CEA.RESULTS To differentiate between the 195 HCs and 101 CRC patients(38 early CRC and 63 advanced CRC patients),the common biomarkers CEA and CAMK1D were used alone or in combination to evaluate their diagnostic value.The area under the curves(AUCs)of CEA and CAMK1D were 0.773(0.711,0.834)and 0.935(0.907,0.964),respectively.When CEA and CAMK1D were analyzed together,the AUC was 0.964(0.945,0.982).In differentiating between the HC and early CRC groups,the AUC was 0.978(0.960,0.995),and the sensitivity and specificity were 88.90%and 90.80%,respectively.In differentiating between the HC and advanced CRC groups,the AUC was 0.956(0.930,0.981),and the sensitivity and specificity were 81.30%and 95.90%,respectively.After building the diagnostic model containing CEA and CAMK1D,the AUC of the CEA and CAMK1D joint model was 0.906(0.858,0.954)for the validation group.In differentiating between the HC and early CRC groups,the AUC was 0.909(0.844,0.973),and the sensitivity and specificity were 93.00%and 83.30%,respectively.In differentiating between the HC and advanced CRC groups,the AUC was 0.904(0.849,0.959),and the sensitivity and specificity were 93.00%and 75.00%,respectively.CONCLUSION We built a diagnostic model including CEA and CAMK1D for differentiating between HC individuals and CRC patients.Compared with the common biomarker CEA alone,the diagnostic model exhibited significant improvement.
文摘目的探讨丙型肝炎病毒NS5A反式调节蛋白9(hepatitis C virus NS5Atransactivated protein 9,NS5ATP9)在乙型肝炎病毒(hepatitis B virus,HBV)共价闭合环状DNA(covalently closed circular DNA,cccDNA)形成与转录中的作用机制。方法利用1.3拷贝HBV表达质粒转染Huh7和HepG2细胞、整合有4拷贝HBV基因组的HepG2.2.15细胞、在诱导型四环素启动子控制下表达HBV的HepAD38细胞构建NS5ATP9过表达或干扰的HBV细胞模型,收集样品和细胞上清液,提取RNA、HBV核心DNA(coreDNA)、cccDNA和蛋白,利用酶联免疫吸附试验、实时荧光定量聚合酶链反应(polymerase chain reaction,PCR)、Southern blot和Western blot技术检测HBV总RNA、前基因组RNA(pregenomic RNA,pgRNA)、乙型肝炎病毒s抗原(hepatitis B virus s antigene,HBsAg)、乙型肝炎病毒e抗原(hepatitis B virus e antigene,HBeAg)、松弛环状DNA(relax circular DNA,rcDNA)以及cccDNA水平。在HepG2细胞中转染乙型肝炎病毒x蛋白(hepatitis B virus x protein,HBx),通过免疫荧光成像及免疫共沉淀方法检测NS5ATP9与HBx的结合情况。双荧光素酶报告基因实验检测NS5ATP9对HBx启动子活性的影响。利用Huh7细胞转染HBV1.3及HBV稳定表达细胞株HepG2.2.15和HepAD38转染NS5ATP9过表达/干扰质粒,通过Western blot技术检测DDB1和SMC6的蛋白水平。结果在HBV病毒活跃的细胞中,NS5ATP9 mRNA水平[HepG2.2.15细胞:1.891±0.567比1.00±0.034,t=2.87,P=0.0351;HepAD38 tet+细胞:1.978±0.399比1.00±0.034,t=4.131,P=0.0091;HepAD38 tet-细胞:2.642±0.672比1.00±0.034,t=4.127,P=0.0091]和蛋白水平均显著增加。过表达NS5ATP9后可显著增加HBeAg[(5.402±0.327)S/COV比(2.68±0.552)S/COV,t=7.35,P=0.0018]、HBsAg[(2.846±0.185)S/COV比(1.512±0.221)S/COV,t=8.02,P=0.0013]、HBV pgRNA及rcDNA的表达水平,而干扰NS5ATP9后此增加作用消失[HBeAg:(2.029±0.09)S/COV比(3.733±0.445)S/COV,t=6.501,P=0.0029;HBsAg:(1.501±0.105)S/COV比(1.878±0.174)S/COV,t=3.216,P=0.0324)]。机制研究显示,NS5ATP9和HBx蛋白主要位于细胞核核仁内,并具有共定位信号,且NS5ATP9可显著提高HBx启动子(1071.06±79.44比488.47±40.12,t=13.09,P=0.00012)的转录活性。另外,过表达NS5ATP9可显著降低DDB1和SMC6的蛋白水平,而沉默NS5ATP9则可显著提高DDB1和SMC6的蛋白水平。结论HBV上调NS5ATP9的表达,形成HBV-NS5ATP9-HBV cccDNA-HBV的正反馈环路,NS5ATP9通过与HBx相互作用上调肝细胞中HBV cccDNA的形成与转录,进而促进慢性乙型肝炎的发生发展。
文摘250 million people worldwide continue to be chronically infected with the virus.While patients may be treated with nucleoside/nucleotide analogues,this only suppresses HBV titre to sub-detection levels without eliminating the persistent HBV covalently closed circular DNA(cccDNA)genome.As a result,HBV infection cannot be cured,and the virus reactivates when conditions are favorable.Interferons(IFNs)are cytokines known to induce powerful antiviral mechanisms that clear viruses from infected cells.They have been shown to induce cccDNA clearance,but their use in the treatment of HBV infection is limited as HBVtargeting immune cells are exhausted and HBV has evolved multiple mechanisms to evade and suppress IFN signalling.Thus,to fully utilize IFN-mediated intracellular mechanisms to effectively eliminate HBV,instead of direct IFN administration,novel strategies to sustain IFN-mediated anti-cccDNA and antiviral mechanisms need to be developed.This review will consolidate what is known about how IFNs act to achieve its intracellular antiviral effects and highlight the critical interferon-stimulated gene targets and effector mechanisms with potent anti-cccDNA functions.These include cccDNA degradation by APOBECs and cccDNA silencing and transcription repression by epigenetic modifications.In addition,the mechanisms that HBV employs to disrupt IFN signalling will be discussed.Drugs that have been developed or are in the pipeline for components of the IFN signalling pathway and HBV targets that detract IFN signalling mechanisms will also be identified and discussed for utility in the treatment of HBV infections.Together,these will provide useful insights into design strategies that specifically target cccDNA for the eradication of HBV.
文摘Hepatitis B virus(HBV) infection is a major global health problem. Although current therapies, such as the use of nucleos(t)ide analogs, inhibit HBV replication efficiently, they do not eliminate covalently closed circular DNA(ccc DNA), which persists in hepatocyte nuclei. As HBV ccc DNA is a viral transcription template, novel therapeutic approaches to directly target HBV ccc DNA are necessary to completely eradicate persistent HBV infections. HBV ccc DNA levels in HBV-infected human liver cells are extremely low; thus, more reliable and simple measurement methods are needed to correctly monitor their levels during therapeutic treatment. Although reverse transcription-polymerase chain reaction or Southern blot procedures are currently used in research studies, these methods are not completely reliable and are also time-consuming and labor-intensive. Genome editing technologies, such as zinc finger nucleases, transcription activator-like effector nucleases, and the clustered regularly interspaced short palindromic repeats/Cas9(CRISPR/Cas9) system, which are designed to target specific DNA sequences, represent highly promising potential therapeutic tools. In particular, the CRISPR/Cas9 system is an easily customizable sequencespecific nuclease with high flexibility and may be the most feasible approach to target HBV ccc DNA. Further research to develop easier, safer, and more effective protocols should be pursued.
基金Beijing Municipal Science & Technology Commission, No. H020920020690
文摘AIM:To evaluate the effects of antiviral agents and HBV genotypes on intrahepatic covalently closed circular DNA (ccc DNA) in HBeAg-positive chronic hepatitis B patients. METHODS:Seventy-one patients received lamivudine (n = 35), or sequential therapy with lamivudine-interferon alpha 2b (IFN-α 2b, n = 24) for 48 wk, or IFN-α 2b (n = 12) for 24 wk. All subjects were followed up for 24 wk. Intrahepatic ccc DNA was measured quantitatively by PCR. HBV genotypes were analyzed by PCR-RFLP. RESULTS:Sequential lamivudine-INF-α therapy, lamivudine and INF-α monotherapy reduced ccc DNA of 1.7 log, 1.4 log and 0.8 log, respectively (P < 0.05). Seventeen out of the 71 patients developed HBeAg seroconversion, the reduction of ccc DNA in the HBeAg seroconversion patients was more significant than that in the HBeAg positive patients (3.0 log vs 1.6 log, P = 0.0407). Twenty-four weeks after antiviral therapy withdrawal, 16 patients had a sustained virological response, the baseline intrahepatic ccc DNA in the patients with a sustained virological response was significantly lower than that in the patients with virological rebound (4.6 log vs 5.4 log, P = 0.0472). HBV genotype C accounted for 85.9% (n = 61), and genotype B for 14.1% (n = 10), respectively, in the 71 patients. There was no significant difference in the change of ccc DNA level between HBV genotypes C and B (2.1 log vs 1.9 log). CONCLUSION:Forty-eight week sequential lamivudine-INF-α therapy and lamivudine monotherapy reduce ccc DNA more significantly than 24-wk INF-α monotherapy. Low baseline intrahepatic ccc DNA level may predict the long-term efficacy of antiviral treatment. HBV genotypes C and B have no obvious influence on ccc DNA load.
基金Supported by International Cooperation 2021 with Indonesia from the Regione of Friuli Venezia Giulia(Prot.0015911/P)to the FIF.
文摘Chronic infection with hepatitis B virus(HBV)remains a major global health problem,especially in developing countries.It may lead to prolonged liver damage,fibrosis,cirrhosis,and hepatocellular carcinoma.Persistent chronic HBV infection is related to host immune response and the stability of the covalently closed circular DNA(cccDNA)in human hepatocytes.In addition to being essential for viral transcription and replication,cccDNA is also suspected to play a role in persistent HBV infections or hepatitis relapses since cccDNA is very stable in non-dividing human hepatocytes.Understanding the pathogenicity and oncogenicity of HBV components would be essential in the development of new diagnostic tools and treatment strategies.This review summarizes the role and molecular mechanisms of HBV cccDNA in hepatocyte transformation and hepatocarcinogenesis and current efforts to its detection and targeting.
基金Supported by National Natural Science Foundation of China,No. 81972010National Key Research and Development Program of China,No. 2020YFC2002700National Key Research and Development Program of China,No. 2020YFC2004604。
文摘BACKGROUND Colorectal cancer(CRC) is the third most common cancer worldwide, and it is the second leading cause of death from cancer in the world, accounting for approximately 9% of all cancer deaths. Early detection of CRC is urgently needed in clinical practice.AIM To build a multi-parameter diagnostic model for early detection of CRC.METHODS Total 59 colorectal polyps(CRP) groups, and 101 CRC patients(38 early-stage CRC and 63 advanced CRC) for model establishment. In addition, 30 CRP groups,and 62 CRC patients(30 early-stage CRC and 32 advanced CRC) were separately included to validate the model. 51 commonly used clinical detection indicators and the 4 extrachromosomal circular DNA markers NDUFB7, CAMK1D, PIK3CD and PSEN2 that we screened earlier. Four multi-parameter joint analysis methods:binary logistic regression analysis, discriminant analysis, classification tree and neural network to establish a multi-parameter joint diagnosis model.RESULTS Neural network included carcinoembryonic antigen(CEA), ischemia-modified albumin(IMA),sialic acid(SA), PIK3CD and lipoprotein a(LPa) was chosen as the optimal multi-parameter combined auxiliary diagnosis model to distinguish CRP and CRC group, when it differentiated 59CRP and 101 CRC, its overall accuracy was 90.8%, its area under the curve(AUC) was 0.959(0.934,0.985), and the sensitivity and specificity were 91.5% and 82.2%, respectively. After validation,when distinguishing based on 30 CRP and 62 CRC patients, the AUC was 0.965(0.930-1.000), and its sensitivity and specificity were 66.1% and 70.0%. When distinguishing based on 30 CRP and 32early-stage CRC patients, the AUC was 0.960(0.916-1.000), with a sensitivity and specificity of 87.5% and 90.0%, distinguishing based on 30 CRP and 30 advanced CRC patients, the AUC was 0.970(0.936-1.000), with a sensitivity and specificity of 96.7% and 86.7%.CONCLUSION We built a multi-parameter neural network diagnostic model included CEA, IMA, SA, PIK3CD and LPa for early detection of CRC, compared to the conventional CEA, it showed significant improvement.
文摘The availability of the plastid genome sequences is one of the bases for comparative,functional,and structural genomic studies of plastid-containing living organisms,in addition to the application
