Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
Antimicrob Agents Chemother. 2010 Aug;54(8):3179-86. doi: 10.1128/AAC.00113-10. Epub 2010 May 24.
Splicing of messenger RNAs is regulated by site-specific binding of members of the serine-arginine-rich (SR) protein family, and SR protein kinases (SRPK) 1 and 2 regulate overall activity of the SR proteins by phosphorylation of their RS domains. We have reported that specifically designed SRPK inhibitors suppressed effectively several DNA and RNA viruses in vitro and in vivo. Here, we show that an SRPK inhibitor, SRPIN340, suppressed in a dose-dependent fashion expression of a hepatitis C virus (HCV) subgenomic replicon and replication of the HCV-JFH1 clone in vitro. The inhibitory effects were not associated with antiproliferative or nonspecific cytotoxic effects on the host cells. Overexpression of SRPK1 or SRPK2 resulted in augmentation of HCV replication, while small interfering RNA (siRNA) knockdown of the SRPKs suppressed HCV replication significantly. Immunocytochemistry showed that SRPKs and the HCV core and NS5A proteins colocalized to some extent in the perinuclear area. Our results demonstrate that SRPKs are host factors essential for HCV replication and that functional inhibitors of these kinases may constitute a new class of antiviral agents against HCV infection.
信使 RNA 的剪接受丝氨酸/精氨酸丰富（SR）蛋白家族成员的特异性结合调控，而 SR 蛋白激酶（SRPK）1 和 2 通过磷酸化其 RS 结构域来调节 SR 蛋白的整体活性。我们已经报道，专门设计的 SRPK 抑制剂可有效抑制几种 DNA 和 RNA 病毒在体外和体内的复制。在这里，我们表明，一种 SRPK 抑制剂 SRPIN340 以剂量依赖性方式抑制丙型肝炎病毒（HCV）亚基因组复制子的表达和 HCV-JFH1 克隆在体外的复制。抑制作用与对宿主细胞的抗增殖或非特异性细胞毒性作用无关。SRPK1 或 SRPK2 的过表达导致 HCV 复制增强，而 SRPK 的小干扰 RNA（siRNA）敲低则显著抑制 HCV 复制。免疫细胞化学显示，SRPK 与 HCV 核心和 NS5A 蛋白在核周区在一定程度上共定位。我们的结果表明，SRPK 是 HCV 复制所必需的宿主因子，这些激酶的功能性抑制剂可能构成针对 HCV 感染的一类新的抗病毒药物。
