24-dehydrocholesterol reductase(DHCR24) inhibitor suppresses HCV replication

丙型肝炎病毒（HCV）经常引起慢性肝炎、肝硬化和肝细胞癌（HCC）。我们之前建立了表达HepG2细胞的条件全长HCV基因，并在传代44天后观察到它们的致瘤性增加（RzM6 44天细胞）。为了明确是否存在根据致瘤性而改变表达水平的抗原，我们建立了针对这些细胞的单克隆抗体（MoAbs）。建立了1000多种单克隆抗体，并对其对RzM6 44天细胞的反应进行了表征。几个克隆对这些细胞具有明显不同的反应性，我们首先鉴定了克隆2-152，它识别了大约55千道尔顿（kDa）分子（p55）。因此，我们通过MALDI-TOF/MS鉴定p55分子为24-脱氢胆固醇还原酶（DHCR24）。DHCR24是胆固醇生物合成途径中的一种酶。U18666A是DHCR24的抑制剂，抑制丙型肝炎病毒（HCV）复制子细胞的复制。我们研究了U18666A对HCV基因型1a或1b感染的人源化肝脏嵌合小鼠的抗HCV作用。我们给HCV感染的嵌合小鼠注射U18666A，成功地将血清和肝脏中的HCV RNA水平降低到治疗前8天水平的1/10-1/100。此外，与聚乙二醇化干扰素联合治疗将HCV RNA水平降低到对照水平的1/1000以下。我们强烈建议抑制DHCR24可以减少HCV的复制，因此DHCR24抑制剂可能是治疗HCV感染的一种新型药物。

Hepatitis C virus (HCV) frequently causes chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). We previously established the conditional full-length HCV gene expressing HepG2 cells and observed their increased tumorigenicity after 44 days passage (RzM6 44 days cells). In order to clarify the existence of antigens whose expression level has been changed according to the tumorigenicity, we established the monoclonal antibodies (MoAbs) against these cells. Over one thousand monoclonal antibodies were established, and their reactivities to RzM6 44 days cells were characterized. Several clones with significantly different reactivity to these cells, we first characterized clone 2-152, and it recognized approximately 55 killodalton (kDa.) molecule (p55). Therefore, we identified p55 molecule by MALDI-TOF/MS as 24-dehydrocholesterol reductase (DHCR24).DHCR24 is a enzyme in the cholesterol biosynthetic pathway. U18666A is an inhibitor of DHCR24 and suppresses replication of the hepatitis C virus (HCV) replicon cells. We investigated the anti-HCV effect of U18666A against intact HCV using chimeric mice with humanized liver infected with HCV genotype 1a or 1b. We administered U18666A into HCV infected chimeric mice and succeeded in reducing the HCV RNA levels in serum and liver to 1/10-1/100 of the levels prior to the 8 day treatment. Furthermore, combined treatment with pegylated interferon reduced the HCV RNA levels to less than 1/1000 of the control levels. We strongly suggest that suppression of DHCR24 reduces HCV replication, and therefore that the DHCR24 inhibitor is potentially a novel drug in the treatment of HCV infection.