title: The Antiviral Alkaloid Berberine Reduces Chikungunya Virus-Induced Mitogen-Activated Protein Kinase Signaling.
abstract: Chikungunya virus (CHIKV) has infected millions of people in the tropical and subtropical regions since its reemergence in the last decade. We recently identified the nontoxic plant alkaloid berberine as an antiviral substance against CHIKV in a high-throughput screen. Here, we show that berberine is effective in multiple cell types against a variety of CHIKV strains, also at a high multiplicity of infection, consolidating the potential of berberine as an antiviral drug. We excluded any effect of this compound on virus entry or on the activity of the viral replicase. A human phosphokinase array revealed that CHIKV infection specifically activated the major mitogen-activated protein kinase (MAPK) signaling pathways extracellular signal-related kinase (ERK), p38 and c-Jun NH2-terminal kinase (JNK). Upon treatment with berberine, this virus-induced MAPK activation was markedly reduced. Subsequent analyses with specific inhibitors of these kinases indicated that the ERK and JNK signaling cascades are important for the generation of progeny virions. In contrast to specific MAPK inhibitors, berberine lowered virus-induced activation of all major MAPK pathways and resulted in a stronger reduction in viral titers. Further, we assessed the in vivo efficacy of berberine in a mouse model and measured a significant reduction of CHIKV-induced inflammatory disease. In summary, we demonstrate the efficacy of berberine as a drug against CHIKV and highlight the importance of the MAPK signaling pathways in the alphavirus infectious cycle.
  
  
  OBJECTIVE
  Chikungunya virus (CHIKV) is a mosquito-borne virus that causes severe and persistent muscle and joint pain and has recently spread to the Americas. No licensed drug exists to counter this virus. In this study, we report that the alkaloid berberine is antiviral against different CHIKV strains and in multiple human cell lines. We demonstrate that berberine collectively reduced the virus-induced activation of cellular mitogen-activated protein kinase signaling. The relevance of these signaling cascades in the viral life cycle was emphasized by specific inhibitors of these kinase pathways, which decreased the production of progeny virions. Berberine significantly reduced CHIKV-induced inflammatory disease in a mouse model, demonstrating efficacy of the drug in vivo Overall, this work makes a strong case for pursuing berberine as a potential anti-CHIKV therapeutic compound and for exploring the MAPK signaling pathways as antiviral targets against alphavirus infections.
authors.affiliation: Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland finny.varghese@helsinki.fi tero.ahola@helsinki.fi.
authors.forename: Finny S
authors.initials: FS
authors.lastname: Varghese
authors.affiliation: Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Bastian
authors.initials: B
authors.lastname: Thaa
authors.affiliation: Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore.
authors.forename: Siti Naqiah
authors.initials: SN
authors.lastname: Amrun
authors.affiliation: Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore.
authors.forename: Diane
authors.initials: D
authors.lastname: Simarmata
authors.affiliation: Institute of Technology, University of Tartu, Tartu, Estonia.
authors.forename: Kai
authors.initials: K
authors.lastname: Rausalu
authors.affiliation: Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
authors.forename: Tuula A
authors.initials: TA
authors.lastname: Nyman
authors.affiliation: Institute of Technology, University of Tartu, Tartu, Estonia.
authors.forename: Andres
authors.initials: A
authors.lastname: Merits
authors.affiliation: Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Gerald M
authors.initials: GM
authors.lastname: McInerney
authors.affiliation: Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore.
authors.forename: Lisa F P
authors.initials: LFP
authors.lastname: Ng
authors.affiliation: Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland finny.varghese@helsinki.fi tero.ahola@helsinki.fi.
authors.forename: Tero
authors.initials: T
authors.lastname: Ahola
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D001599:Berberine / Q000494:pharmacology*; D002460:Cell Line; D065632:Chikungunya Fever / Q000188:drug therapy* / Q000378:metabolism; D002646:Chikungunya virus / Q000187:drug effects*; D006224:Cricetinae; D057809:HEK293 Cells; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects*; D014709:Vero Cells; D014775:Virus Activation / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000470:Alkaloids; D000998:Antiviral Agents; D001599:Berberine; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases