24-dehydrocholesterol reductase(DHCR24) inhibitor suppresses HCV replication

丙型肝炎病毒(丙型肝炎病毒)常导致慢性肝炎、肝硬变和肝细胞癌。我们先前建立了有条件的全长丙型肝炎病毒基因表达的HepG2细胞，并观察到其在传代44天后(RzM6 44天细胞)的致瘤性增加。为了阐明是否存在表达水平随致瘤性而改变的抗原，我们建立了针对这些细胞的单抗。制备了1000多株单抗，并对其与RzM6 44天细胞的反应性进行了鉴定。几个对这些细胞具有显著不同反应性的克隆，我们首先对克隆2-152进行了鉴定，它识别了大约55kloalton(KDa)。分子(P55)。因此，我们用MALDI-TOF/MS鉴定了P55分子为24-脱氢胆固醇还原酶(24-DHO-CHO-REDUTase)，它是胆固醇生物合成途径中的一个酶。U18666A是一种DHCR24的抑制剂，可以抑制丙型肝炎病毒复制子细胞的复制。我们利用人肝感染丙型肝炎病毒1a或1b的嵌合小鼠，研究了U18666A对完整丙型肝炎病毒的抗丙型肝炎病毒作用。我们给感染了丙型肝炎病毒的嵌合小鼠注射U18666A，成功地将血清和肝脏中的丙型肝炎病毒RNA水平降低到治疗前的1/10-1/100。此外，与聚乙二醇化干扰素联合治疗将丙型肝炎病毒RNA水平降低到不到对照水平的1/1000。我们强烈地认为，抑制dhr24可以减少丙型肝炎病毒的复制，因此dhr24抑制剂有可能成为治疗丙型肝炎病毒感染的一种新药。

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.