title: Kallistatin ameliorates influenza virus pathogenesis by inhibition of kallikrein-related peptidase 1-mediated cleavage of viral hemagglutinin.
abstract: Proteolytic cleavage of the hemagglutinin (HA) of influenza virus by host trypsin-like proteases is required for viral infectivity. Some serine proteases are capable of cleaving influenza virus HA, whereas some serine protease inhibitors (serpins) inhibit the HA cleavage in various cell types. Kallikrein-related peptidase 1 (KLK1, also known as tissue kallikrein) is a widely distributed serine protease. Kallistatin, a serpin synthesized mainly in the liver and rapidly secreted into the circulation, forms complexes with KLK1 and inhibits its activity. Here, we investigated the roles of KLK1 and kallistatin in influenza virus infection. We show that the levels of KLK1 increased, whereas those of kallistatin decreased, in the lungs of mice during influenza virus infection. KLK1 cleaved H1, H2, and H3 HA molecules and consequently enhanced viral production. In contrast, kallistatin inhibited KLK1-mediated HA cleavage and reduced viral production. Cells transduced with the kallistatin gene secreted kallistatin extracellularly, which rendered them more resistant to influenza virus infection. Furthermore, lentivirus-mediated kallistatin gene delivery protected mice against lethal influenza virus challenge by reducing the viral load, inflammation, and injury in the lung. Taking the data together, we determined that KLK1 and kallistatin contribute to the pathogenesis of influenza virus by affecting the cleavage of the HA peptide and inflammatory responses. This study provides a proof of principle for the potential therapeutic application of kallistatin or other KLK1 inhibitors for influenza. Since proteolytic activation also enhances the infectivity of some other viruses, kallistatin and other kallikrein inhibitors may be explored as antiviral agents against these viruses.
authors.affiliation: Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan, Taiwan.
authors.forename: Chia-Hsing
authors.initials: CH
authors.lastname: Leu
authors.affiliation: Department of Microbiology and Immunology, National Cheng Kung University Medical College, Tainan, Taiwan.
authors.forename: Mei-Lin
authors.initials: ML
authors.lastname: Yang
authors.affiliation: Department of Microbiology and Immunology, National Cheng Kung University Medical College, Tainan, Taiwan.
authors.forename: Nai-Hui
authors.initials: NH
authors.lastname: Chung
authors.affiliation: Department of Biochemistry and Molecular Biology, National Cheng Kung University Medical College, Tainan, Taiwan.
authors.forename: Yen-Jang
authors.initials: YJ
authors.lastname: Huang
authors.affiliation: Department of Biochemistry and Molecular Biology, National Cheng Kung University Medical College, Tainan, Taiwan.
authors.forename: Yu-Chu
authors.initials: YC
authors.lastname: Su
authors.affiliation: Department of Biochemistry and Molecular Biology, National Cheng Kung University Medical College, Tainan, Taiwan.
authors.forename: Yi-Cheng
authors.initials: YC
authors.lastname: Chen
authors.affiliation: Department of Pathology, Tainan Hospital, Ministry of Health and Welfare, Tainan, Taiwan.
authors.forename: Chia-Cheng
authors.initials: CC
authors.lastname: Lin
authors.affiliation: Department of Urology, Tainan Hospital, Ministry of Health and Welfare, Tainan, Taiwan.
authors.forename: Gia-Shing
authors.initials: GS
authors.lastname: Shieh
authors.affiliation: Institute of Medical Sciences, Tzu-Chi University, Hualien, Taiwan.
authors.forename: Meng-Ya
authors.initials: MY
authors.lastname: Chang
authors.affiliation: Institute of Molecular Medicine, National Cheng Kung University Medical College, Tainan, Taiwan.
authors.forename: Shainn-Wei
authors.initials: SW
authors.lastname: Wang
authors.affiliation: National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan.
authors.forename: Yao
authors.initials: Y
authors.lastname: Chang
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, USA.
authors.forename: Julie
authors.initials: J
authors.lastname: Chao
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, USA.
authors.forename: Lee
authors.initials: L
authors.lastname: Chao
authors.affiliation: Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan, Taiwan Department of Biochemistry and Molecular Biology, National Cheng Kung University Medical College, Tainan, Taiwan alshiau@mail.ncku.edu.tw wumolbio@mail.ncku.edu.tw.
authors.forename: Chao-Liang
authors.initials: CL
authors.lastname: Wu
authors.affiliation: Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan, Taiwan Department of Microbiology and Immunology, National Cheng Kung University Medical College, Tainan, Taiwan alshiau@mail.ncku.edu.tw wumolbio@mail.ncku.edu.tw.
authors.forename: Ai-Li
authors.initials: AL
authors.lastname: Shiau
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000627:therapeutic use*; D015153:Blotting, Western; D002460:Cell Line; D004285:Dogs; D004797:Enzyme-Linked Immunosorbent Assay; D006389:Hemagglutinins, Viral / Q000378:metabolism*; D006801:Humans; D007251:Influenza, Human / Q000188:drug therapy*; D051379:Mice; D008810:Mice, Inbred C57BL; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015843:Serpins / Q000627:therapeutic use*; D020840:Tissue Kallikreins / Q000378:metabolism*
chemical_list: D000998:Antiviral Agents; D006389:Hemagglutinins, Viral; D015843:Serpins; C051324:kallistatin; D020840:Tissue Kallikreins