title: Inhibition of hepatitis C virus replication by a specific inhibitor of serine-arginine-rich protein kinase.
abstract: 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.
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Karakama
authors.forename: Naoya
authors.initials: N
authors.lastname: Sakamoto
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Itsui
authors.forename: Mina
authors.initials: M
authors.lastname: Nakagawa
authors.forename: Megumi
authors.initials: M
authors.lastname: Tasaka-Fujita
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nishimura-Sakurai
authors.forename: Sei
authors.initials: S
authors.lastname: Kakinuma
authors.forename: Masaya
authors.initials: M
authors.lastname: Oooka
authors.forename: Seishin
authors.initials: S
authors.lastname: Azuma
authors.forename: Kiichiro
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Onogi
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hagiwara
authors.forename: Mamoru
authors.initials: M
authors.lastname: Watanabe
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology*; D024882:Drug Resistance, Viral; D016174:Hepacivirus / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D018936:Hepatitis C Antigens / Q000235:genetics / Q000378:metabolism; D006801:Humans; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D012093:Replicon / Q000187:drug effects / Q000502:physiology; D014758:Viral Core Proteins / Q000235:genetics / Q000378:metabolism; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication / Q000187:drug effects*; D012324:RNA-Dependent RNA Polymerase
chemical_list: D000998:Antiviral Agents; D018936:Hepatitis C Antigens; D017346:Protein Serine-Threonine Kinases; D034741:RNA, Small Interfering; D014758:Viral Core Proteins; D017361:Viral Nonstructural Proteins; C087728:SRPK1 protein, human; C110522:SRPK2 protein, human; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase