Identification of a Ribavirin‐resistant NS5B mutation of hepatitis C virus during ribavirin monotherapy
Identification of a Ribavirin‐resistant NS5B mutation of hepatitis C virus during ribavirin monotherapy
复制标题
利巴韦林单药治疗期间丙型肝炎病毒耐利巴韦林 NS5B 突变的鉴定
DOI：
10.1002/hep.1840380413
复制
发表时间：
2003
期刊：
影响因子：
13.5
通讯作者：
M. Lai
中科院分区：
文献类型：
--
作者：
K. Young;K. Lindsay;K. Lee;Wen;Jian‐Wen He;S. Milstein;M. Lai
利巴韦林（Ribavirin，RBV）是一种鸟苷类似物，在体外可通过引起致死突变和抑制RNA聚合酶而发挥抗丙型肝炎病毒（Hepatitis C virus，HCV）的作用，但其临床作用机制尚不清楚。为了验证RBV在体内既能作为RNA诱变剂又能抑制病毒RNA合成的假设，我们研究了接受RBV、安慰剂或干扰素α（IFN-α）单药治疗的患者中HCV RNA非结构（NS）5 B区核苷酸序列的演变。RBV组显示HCV RNA准种的进化速率比IFN-α或安慰剂组略快。RBV优先引起A至G和U至A突变。有趣的是，在RBV治疗期间，在所有（5/5）感染HCV基因型1a的患者中出现NS 5 B氨基酸415 Phe-to-Tyr（F415 Y）突变。随后，在停止治疗后，一些患者再次出现亲本415 F菌株。然后在Huh 7细胞中使用HCV亚基因组复制子研究NS 5 B415处的氨基酸取代对HCV RNA复制的影响。我们发现，用RBV处理复制子细胞以剂量依赖性方式降低了NS 5 B415 F复制子的HCV RNA水平，但不是NS 5 B415 Y。因此，NS 5 B F415 Y突变代表RBV抗性变体。NS 5 B蛋白的三维建模和结构分析显示，第415个氨基酸位于拇指亚结构域的P螺旋区域，该区域可能与推定的RNA结合裂缝中的模板引物双链体的小沟相互作用。总之，RBV可以作为HCV感染患者中HCV RNA的弱诱变剂。此外，在NS 5 B中选择具有单个氨基酸取代的RBV抗性变体表明RBV可能直接与HCV RNA聚合酶相互作用，从而干扰其酶活性。（Hepatology 2003;38：869-878）。
Ribavirin (RBV), a guanosine analogue, has been suggested to exert an antiviral action against hepatitis C virus (HCV) by causing lethal mutations and suppressing RNA polymerase in vitro, but the mechanism of its clinical therapeutic effects is currently unknown. To test the hypothesis that RBV could act both as an RNA mutagen and inhibit viral RNA synthesis in vivo, we studied the evolution of the nucleotide sequences of HCV RNA at the nonstructural (NS) 5B region in patients receiving RBV, placebo, or interferon alfa (IFN‐α) monotherapy. The RBV group showed a slightly more accelerated evolution rate of HCV RNA quasispecies than either the IFN‐α or placebo group. RBV caused preferentially A‐to‐G and U‐to‐A mutations. Interestingly, an NS5B amino acid 415 Phe‐to‐Tyr (F415Y) mutation emerged in all (5 of 5) patients infected with HCV genotype 1a during the RBV treatment. Subsequently, the parental 415F strain reemerged in some patients after the treatment was discontinued. The effect of the amino acid substitution at NS5B415 on HCV RNA replication was then investigated using an HCV subgenomic replicon in Huh7 cells. We showed that treatment of replicon cells with RBV reduced the HCV RNA level of NS5B415F replicon, but not NS5B415Y, in a dose‐dependent manner. Thus, NS5B F415Y mutation represents an RBV‐resistant variant. The 3‐dimensional modeling and structure analysis of NS5B protein revealed that the 415th amino acid is located at the P helix region of the thumb subdomain, which may interact with the minor groove of the template‐primer duplex in the putative RNA‐binding cleft. In conclusion, RBV could work as a weak mutagen for HCV RNA in HCV‐infected patients. Furthermore, the selection of an RBV‐resistant variant with a single amino acid substitution in NS5B suggested that RBV may directly interact with HCV RNA polymerase, thus interfering with its enzymatic activity. (Hepatology 2003;38:869–878).