Differentiation-dependent redistribution of heparan sulfate in epithelial intestinal Caco-2 cells leads to basolateral entry of cytomegalovirus.
Human cytomegalovirus (HCMV) causes a broad spectrum of clinical manifestations in immunocompromised patients, including infection of the gastrointestinal tract. To investigate the role of epithelial cells in the gastrointestinal HCMV disease, we used the intestinal epithelial cell line Caco-2, which is permissive for HCMV replication. In differentiated Caco-2 cells, we showed previously that HCMV infection proceeds preferentially from the basolateral membrane, suggesting that receptors for HCMV may be contained predominantly in the basolateral membrane (A. Esclatine et al., 2000, J. Virol. 74, 513-517). Therefore, we examined expression and localization in Caco-2 cells of heparan sulfate (HS) proteoglycan and annexin II, previously implicated in initial events of HCMV infection. We observed that annexin II is expressed in Caco-2 cells, but is not essential for entry of HCMV. We showed that, during the differentiation process, HS, initially present on the entire surface of the membrane of undifferentiated cells, ultimately became sequestered at the basolateral cell surface of fully differentiated cells. We established by biochemical assays that membrane-associated HS proteoglycan mediates both viral attachment to, and subsequent infection of, Caco-2 cells, regardless of the cell differentiation state. Thus, the redistribution of HS is implicated in the basolateral entry of HCMV into differentiated Caco-2 cells.
Esclatine
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Institut National de la Santé et de la Recherche Médicale, Unité 510, Pathogènes et Fonctions des Cellules Epithéliales Polarisées, Faculté de Pharmacie, Université Paris XI, 92296 Châtenay-Malabry Cedex, France. audrey.esclatine@cep.u-psud.fr
Bellon
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Michelson
S
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Servin
A L
AL
Quéro
A M
AM
Géniteau-Legendre
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M
D000818:Animals; D017306:Annexin A2 / Q000378:metabolism; D001485:Basement Membrane / Q000821:virology; D018938:Caco-2 Cells; D002454:Cell Differentiation / Q000502:physiology*; D016764:Cell Polarity; D003587:Cytomegalovirus / Q000472:pathogenicity* / Q000502:physiology; D020895:Enterocytes / Q000378:metabolism* / Q000821:virology*; D006497:Heparan Sulfate / Q000378:metabolism*; D006801:Humans; D051379:Mice
D017306:Annexin A2; D006497:Heparan Sulfate