Cleavage of influenza virus hemagglutinin by airway proteases TMPRSS2 and HAT differs in subcellular localization and susceptibility to protease inhibitors.
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.
Institute of Virology, Philipps University Marburg, Hans-Meerwein-Strasse 2, 35043 Marburg, Germany.
Eva
E
Böttcher-Friebertshäuser
Catharina
C
Freuer
Frank
F
Sielaff
Sarah
S
Schmidt
Markus
M
Eickmann
Jennifer
J
Uhlendorff
Torsten
T
Steinmetzer
Hans-Dieter
HD
Klenk
Wolfgang
W
Garten
D000818:Animals; D002460:Cell Line; D004285:Dogs; D004318:Doxycycline / Q000494:pharmacology; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000378:metabolism*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000472:pathogenicity*; D008565:Membrane Proteins / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology*; D012697:Serine Endopeptidases / Q000032:analysis / Q000378:metabolism*; D015533:Transcriptional Activation / Q000187:drug effects; D014771:Virion
D019267:Hemagglutinin Glycoproteins, Influenza Virus; D008565:Membrane Proteins; D011480:Protease Inhibitors; D012697:Serine Endopeptidases; C421305:TMPRSS2 protein, human; C112256:human airway trypsin-like protease; D004318:Doxycycline