Expanding the role of 3-O sulfated heparan sulfate in herpes simplex virus type-1 entry.
Heparan sulfate (HS) proteoglycans are commonly exploited by multiple viruses for initial attachment to host cells. Herpes simplex virus-1 (HSV-1) is unique because it can use HS for both attachment and penetration, provided specific binding sites for HSV-1 envelope glycoprotein gD are present. The interaction with gD is mediated by specific HS moieties or 3-O sulfated HS (3-OS HS), which are generated by all but one of the seven isoforms of 3-O sulfotransferases (3-OSTs). Here we demonstrate that several common experimental cell lines express unique sets of 3-OST isoforms. While the isoforms 3-OST-3, -5 and -6 were most commonly expressed, isoforms 3-OST-2 and -4 were undetectable in the cell lines examined. Since most cell lines expressed multiple 3-OST isoforms, we addressed the significance of 3-OS HS in HSV-1 entry by down-regulating 2-O-sulfation, a prerequisite for 3-OS HS formation, by knocking down 2-OST expression by RNA interference (RNAi). 2-OST knockdown was verified by reverse-transcriptase PCR and Western blot analysis, while 3-OS HS knockdown was verified by immunofluorescence. Cells showed a significant decrease in viral entry, suggesting an important role for 3-OS HS. Implicating 3-OS HS further, cells knocked down for 2-OST expression also demonstrated decreased cell-cell fusion when cocultivated with effector cells transfected with HSV-1 glycoproteins. Our findings suggest that 3-OS HS may play an important role in HSV-1 entry into many different cell lines.
O'Donnell
Christopher D
CD
Department of Ophthalmology and Visual Sciences, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA.
Kovacs
Maria
M
Akhtar
Jihan
J
Valyi-Nagy
Tibor
T
Shukla
Deepak
D
D000818:Animals; D002460:Cell Line; D055785:Gene Knockdown Techniques; D006497:Heparan Sulfate / Q000378:metabolism*; D018259:Herpesvirus 1, Human / Q000502:physiology*; D006801:Humans; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D011991:Receptors, Virus / Q000378:metabolism*; D014759:Viral Envelope Proteins / Q000378:metabolism*; D053586:Virus Internalization
D006497:Heparan Sulfate; D034741:RNA, Small Interfering; D011991:Receptors, Virus; D014759:Viral Envelope Proteins; C039447:glycoprotein D, Human herpesvirus 1