Extracellular Hepatitis B Virus RNAs Are Heterogeneous in Length and Circulate as Capsid-Antibody Complexes in Addition to Virions in Chronic Hepatitis B Patients.
Extracellular Hepatitis B Virus RNAs Are Heterogeneous in Length and Circulate as Capsid-Antibody Complexes in Addition to Virions in Chronic Hepatitis B Patients.
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DOI：
10.1128/jvi.00798-18
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发表时间：
2018-12-15
影响因子：
5.4
通讯作者：
Yuan Z
中科院分区：
文献类型：
--
作者：
Bai L;Zhang X;Kozlowski M;Li W;Wu M;Liu J;Chen L;Zhang J;Huang Y;Yuan Z
尽管越来越多的证据表明存在细胞外HBV RNA种类，但其来源和分子形式仍存在争议。除了感染性病毒粒子，已知HBV在其复制周期中分泌几种不完全病毒粒子，包括乙型肝炎B表面抗原（HBsAg）粒子、裸衣壳和空病毒粒子。在这里，我们证明了细胞外HBV RNA与HepAD 38细胞中的裸衣壳和病毒体相关。有趣的是，我们发现无包膜的衣壳以CAC的形式在B型肝炎患者的血液中循环，并与病毒粒子一起作为携带这些RNA分子的载体。此外，细胞外HBV RNA在长度上是异质的，并且代表前基因组RNA（pgRNA）或病毒复制期间不完全逆转录的产物。这些发现为进一步应用细胞外RNA作为HBV持久性的新生物标志物提供了概念基础。在HBV复制细胞培养液和慢性B型肝炎（CH B）患者血清中均检测到细胞外HBV RNA，但其确切来源和组成仍存在争议。在这里，我们证明了细胞外HBV RNA种类的长度是不均匀的，从前基因组RNA的长度到几百个核苷酸。在细胞模型中，这些RNA主要与裸露的衣壳相关，尽管病毒体也含有少数RNA。此外，乙型肝炎B患者血液循环中的HBV RNA以衣壳-抗体复合物（CAC）的形式定位于无包膜的衣壳和病毒粒子中。此外，我们发现细胞外HBV RNA可以作为病毒DNA合成的模板。总之，细胞外HBV RNA主要由pgRNA或在病毒DNA合成过程中被聚合酶的RNase H结构域降解的pgRNA种类组成，并作为CAC和病毒粒子循环。它们在慢性乙型肝炎患者血液循环中的存在可能被用来开发新的HBV持久性生物标志物。重要性尽管越来越多的证据表明存在细胞外HBV RNA种类，但其起源和分子形式仍存在争议。除了感染性病毒粒子，已知HBV在其复制周期中分泌几种不完全病毒粒子，包括乙型肝炎B表面抗原（HBsAg）粒子、裸衣壳和空病毒粒子。在这里，我们证明了细胞外HBV RNA与HepAD 38细胞中的裸衣壳和病毒体相关。有趣的是，我们发现无包膜的衣壳以CAC的形式在B型肝炎患者的血液中循环，并与病毒粒子一起作为携带这些RNA分子的载体。此外，细胞外HBV RNA在长度上是异质的，并且代表前基因组RNA（pgRNA）或病毒复制期间不完全逆转录的产物。这些发现为进一步应用细胞外RNA作为HBV持久性的新生物标志物提供了概念基础。
Although increasing evidence suggests the presence of extracellular HBV RNA species, their origin and molecular forms are still under debate. In addition to the infectious virions, HBV is known to secrete several species of incomplete viral particles, including hepatitis B surface antigen (HBsAg) particles, naked capsids, and empty virions, during its replication cycle. Here, we demonstrated that extracellular HBV RNAs were associated with naked capsids and virions in HepAD38 cells. Interestingly, we found that unenveloped capsids circulate in the blood of hepatitis B patients in the form of CACs and, together with virions, serve as vehicles carrying these RNA molecules. Moreover, extracellular HBV RNAs are heterogeneous in length and represent either pregenomic RNA (pgRNA) or products of incomplete reverse transcription during viral replication. These findings provide a conceptual basis for further application of extracellular RNA species as novel biomarkers for HBV persistence. Extracellular HBV RNA has been detected in both HBV-replicating cell culture media and sera from chronic hepatitis B (CHB) patients, but its exact origin and composition remain controversial. Here, we demonstrated that extracellular HBV RNA species were of heterogeneous lengths, ranging from the length of pregenomic RNA to a few hundred nucleotides. In cell models, these RNAs were predominantly associated with naked capsids, although virions also harbored a minority of them. Moreover, HBV RNAs in hepatitis B patients’ blood circulation were localized in unenveloped capsids in the form of capsid-antibody complexes (CACs) and in virions. Furthermore, we showed that extracellular HBV RNAs could serve as the template for viral DNA synthesis. In conclusion, extracellular HBV RNAs mainly consist of pgRNA or the pgRNA species degraded by the RNase H domain of the polymerase in the process of viral DNA synthesis and circulate as CACs and virions. Their presence in blood circulation of CHB patients may be exploited to develop novel biomarkers for HBV persistence. IMPORTANCE Although increasing evidence suggests the presence of extracellular HBV RNA species, their origin and molecular forms are still under debate. In addition to the infectious virions, HBV is known to secrete several species of incomplete viral particles, including hepatitis B surface antigen (HBsAg) particles, naked capsids, and empty virions, during its replication cycle. Here, we demonstrated that extracellular HBV RNAs were associated with naked capsids and virions in HepAD38 cells. Interestingly, we found that unenveloped capsids circulate in the blood of hepatitis B patients in the form of CACs and, together with virions, serve as vehicles carrying these RNA molecules. Moreover, extracellular HBV RNAs are heterogeneous in length and represent either pregenomic RNA (pgRNA) or products of incomplete reverse transcription during viral replication. These findings provide a conceptual basis for further application of extracellular RNA species as novel biomarkers for HBV persistence.