24-dehydrocholesterol reductase(DHCR24) inhibitor suppresses HCV replication

丙型肝炎病毒（HCV）常引起慢性肝炎、肝硬化和肝细胞癌（HCC）。我们先前建立了表达条件性全长HCV基因的HepG 2细胞，并观察到它们在44天传代后的致瘤性增加（RzM 6 44天细胞）。为了阐明其表达水平已根据致瘤性改变的抗原的存在，我们建立了针对这些细胞的单克隆抗体（MoAbs）。建立了一千多个单克隆抗体，并表征了它们对RzM 6 44天细胞的反应性。几个克隆对这些细胞具有显著不同的反应性，我们首先表征了克隆2-152，它识别约55千道尔顿（kDa）。分子（p55）。因此，我们通过MALDI-TOF/MS鉴定了p55分子为24-脱氢胆固醇还原酶（DHCR 24），DHCR 24是胆固醇生物合成途径中的一种酶。U18666 A是DHCR 24的抑制剂，并抑制丙型肝炎病毒（HCV）复制子细胞的复制。我们研究了U18666 A对完整HCV的抗HCV作用，使用具有感染HCV基因型1a或1b的人源化肝脏的嵌合小鼠。我们将U18666 A给药到HCV感染的嵌合体小鼠中，并成功地将血清和肝脏中的HCV RNA水平降低到8天治疗前水平的1/10-1/100。此外，与聚乙二醇化干扰素的组合治疗将HCV RNA水平降低至低于对照水平的1/1000。我们强烈建议，抑制DHCR 24减少HCV复制，因此，DHCR 24抑制剂是一种潜在的治疗HCV感染的新药。

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.