Certain corona- and influenza viruses utilize type II transmembrane serine proteases
for cell entry, making these enzymes potential drug targets for the treatment of viral
respiratory infections. In this study, the cytotoxicity and inhibitory effects of
seven matriptase/TMPRSS2 inhibitors (MI-21, MI-463, MI-472, MI-485, MI-1900, MI-1903,
and MI-1904) on cytochrome P450 enzymes were evaluated using fluorometric assays.
Additionally, their antiviral activity against influenza A virus subtypes H1N1 and
H9N2 was assessed. The metabolic depletion rates of these inhibitors in human primary
hepatocytes were determined over a 120-min period by LC–MS/MS, and PK parameters were
calculated. The tested compounds, with the exception of MI-21, displayed potent inhibition
of CYP3A4, while all compounds lacked inhibitory effects on CYP1A2, CYP2C9, CYP2C19,
and CYP2D6. The differences between the CYP3A4 activity within the series were rationalized
by ligand docking. Elucidation of PK parameters showed that inhibitors MI-463, MI-472,
MI-485, MI-1900 and MI-1904 were more stable compounds than MI-21 and MI-1903. Anti-H1N1
properties of inhibitors MI-463 and MI-1900 and anti-H9N2 effects of MI-463 were shown
at 20 and 50 µM after 24 h incubation with the inhibitors, suggesting that these inhibitors
can be applied to block entry of these viruses by suppressing host matriptase/TMPRSS2-mediated
cleavage.
