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ABSTRACT: TMPRSS2 is a multidomain type II transmembrane serine protease that cleaves the surface glycoprotein hemagglutinin (HA) of influenza viruses with monobasic cleavage site, which is a prerequisite for virus fusion and propagation. Furthermore, it activates the fusion protein F of the human metapneumovirus and the spike protein S of the SARS coronavirus. Increased TMPRSS2 expression was also described in several tumor entities. Therefore, TMPRSS2 emerged as a potential target for drug design. The catalytic domain of TMPRSS2 was expressed in E. coli and used for an inhibitor screen with previously synthesized inhibitors of various trypsin-like serine proteases. Two inhibitor types were identified, which inhibit TMPRSS2 in the nanomolar range. The first series comprises substrate analogue inhibitors containing a 4-amidinobenzylamide moiety in P1 position, whereby some of these analogues possess inhibition constants around 20 nM. An improved potency was found for second type derived from sulfonylated 3-amindinophenylalanylamide derivates. The most potent derivative of this series inhibits TMPRSS2 with a Ki value of 0.9 nM and showed an efficient blockage of influenza virus propagation in human airway epithelial cells. Based on the inhibitor studies a series of new fluorogenic substrates containing a d-arginine residue in P3 position was synthesized, some of them were efficiently cleaved by TMPRSS2.
Biochemical Journal 03/2013; · 4.90 Impact Factor
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ABSTRACT: Cleavage of the influenza virus hemagglutinin (HA) by host cell proteases is crucial for infectivity and spread of the virus. Some years ago, we identified TMPRSS2 and HAT from human airways as activating proteases of influenza A viruses containing a monobasic HA cleavage site. Therefore, these proteases are considered as potential drug targets. In this report, first we show that HA of influenza B virus is activated by TMPRSS2 and HAT, too. We further demonstrate that benzylsulfonyl-d-arginine-proline-4-amidinobenzylamide (BAPA), which is a potent inhibitor of HAT and TMPRSS2, efficiently suppresses virus propagation in TMPRSS2-expressing human airway epithelial cells by inhibition of HA cleavage. BAPA treatment reduced virus titers of different influenza A and B viruses more than 1000-fold and delayed virus propagation by 24-48h at non-cytotoxic concentrations. A combination of BAPA with the neuraminidase (NA) inhibitor oseltamivir carboxylate efficiently blocked influenza virus replication in airway epithelial cells at remarkable lower concentrations for each compound than treatment with either inhibitor alone. Our studies provide a novel and potent approach for influenza chemotherapy that should be considered for influenza treatment.
Vaccine 10/2012; · 3.77 Impact Factor
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ABSTRACT: A series of substrate analogue inhibitors of the serine protease HAT, containing a 4-amidinobenzylamide moiety as the P1 residue, was prepared. The most potent compounds possess a basic amino acid in the d-configuration as P3 residue. Whereas inhibitor 4 (K(i) 13 nM) containing proline as the P2 residue completely lacks selectivity, incorporation of norvaline leads to a potent inhibitor (15, K(i) 15 nM) with improved selectivity for HAT in comparison to the coagulation proteases thrombin and factor Xa or the fibrinolytic plasmin. Selected inhibitors were able to suppress influenza virus replication in a HAT-expressing MDCK cell model.
Bioorganic & medicinal chemistry letters 08/2011; 21(16):4860-4. · 2.65 Impact Factor
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ABSTRACT: A novel series of amidinohydrazone-derived furin inhibitors was prepared; the most potent compounds 17 and 21 inhibit furin with K(i) values of 0.46 and 0.59μM, respectively. In contrast to inhibitor 17, which still contains a guanidino residue, compound 21 possesses only weakly basic amidinohydrazone groups.
Bioorganic & medicinal chemistry letters 01/2011; 21(2):836-40. · 2.65 Impact Factor
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ABSTRACT: Proteolytic cleavage of the influenza virus surface glycoprotein hemagglutinin (HA) by host cell proteases is crucial for infectivity and virus spread. The proteases HAT (human airway trypsin-like protease) and TMPRSS2 (transmembrane protease serine S1 member 2) known to be present in the human airways were previously identified as proteases that cleave HA. We studied subcellular localization of HA cleavage and cleavage inhibition of seasonal influenza virus A/Memphis/14/96 (H1N1) and pandemic virus A/Hamburg/5/2009 (H1N1) in MDCK cells that express HAT and TMPRSS2 under doxycycline-induced transcriptional activation. We made the following observations: (i) HA is cleaved by membrane-bound TMPRSS2 and HAT and not by soluble forms released into the supernatant; (ii) HAT cleaves newly synthesized HA before or during the release of progeny virions and HA of incoming viruses prior to endocytosis at the cell surface, whereas TMPRSS2 cleaves newly synthesized HA within the cell and is not able to support the proteolytic activation of HA of incoming virions; and (iii) cleavage activation of HA and virus spread in TMPRSS2- and HAT-expressing cells can be suppressed by peptide mimetic protease inhibitors. The further development of these inhibitors could lead to new drugs for influenza treatment.
Journal of Virology 03/2010; 84(11):5605-14. · 5.40 Impact Factor
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ABSTRACT: Furin belongs to the family of proprotein convertases (PCs) and is involved in numerous normal physiological and pathogenic processes, such as viral propagation, bacterial toxin activation, cancer, and metastasis. Furin and related furin-like PCs cleave their substrates at characteristic multibasic consensus sequences, preferentially after an arginine residue. By incorporating decarboxylated arginine mimetics in the P1 position of substrate analogue peptidic inhibitors, we could identify highly potent furin inhibitors. The most potent compound, phenylacetyl-Arg-Val-Arg-4-amidinobenzylamide (15), inhibits furin with a K(i) value of 0.81 nM and has also comparable affinity to other PCs like PC1/3, PACE4, and PC5/6, whereas PC2 and PC7 or trypsin-like serine proteases were poorly affected. In fowl plague virus (influenza A, H7N1)-infected MDCK cells, inhibitor 15 inhibited proteolytic hemagglutinin cleavage and was able to reduce virus propagation in a long-term infection test. Molecular modeling revealed several key interactions of the 4-amidinobenzylamide residue in the S1 pocket of furin contributing to the excellent affinity of these inhibitors.
Journal of Medicinal Chemistry 02/2010; 53(3):1067-75. · 4.80 Impact Factor
