Role of C-type lectins in JUNV arenavirus entry

MARTINEZ, GUADALUPE; BELOUZARD, SANDRINE; CORDO, SANDRA; WHITTAKER, GARY AND CANDURRA, NÉLIDA.

Tucuman, Argentina

Congreso; XLV Annual Meeting of Argentine Society for Biochemical and Molecular Biology Investigation; 2009

SAIB (lSociedad Argentina de Investigación en Bioquímica y Biología Molecular)

Role of DC-SIGN for entry of Junin arenavirus into host cells.Target cell tropism of enveloped viruses is regulated by interactions between viral and cellular factors during transmission, dissemination, and replication within the host. Binding of viral envelope glycoproteins to specific cell-surface receptors determines susceptibility to viral entry. The entry and dissemination of viruses in several families can be mediated by C-type lectins such as hDC-SIGN and hL-SIGN.  DC-SIGN is expressed in dendritic cells (DCs) and has been identified as a receptor for HIV type 1, hepatitis C virus, Ebola virus, cytomegalovirus, Dengue virus, and the SARS coronavirus. In this report we used JUNV GPC pseudotyped particles or JUNV to study their ability to be internalized by hDC- or hL-SIGN. Results from transduction with JUNV pseudovirus show that relative non-permissive CHO cells was markedly enhanced when we over expressed hDC or hL-SIGN. Experiments using non-permissive mouse 3T3 cells showed that they become susceptible to JUNV pseudovirus transduction when they stable express DC- SIGN, or its homologue hL-SIGN, and that transduction of 3T3 stable expressing hDC- or hL- SIGN is blocked by anti–hDC/hL-SIGN antibodies and Mannan. Besides, transduction of permissive feline cell line (Crandall-Reese feline kidney) was also enhanced when they were stable expressing DC-SIGN. Immunofluorescence assays with JUNV (IV4454) showed that infection of Vero cells was significantly enhanced by the over expression of hDC-SIGN or hL-sign, whereas infection of non-permissive murine cell line, 3T3, can be rescued by the expression of hDC-or hL-SIGN. Treatment with Mannan considerably reduced infection, in immunofluorescence and PFU assays, of this lectin expressing cell lines, whereas anti-hDC/hL-SIGN antibodies showed considerable reduction of infection as seen by PFU assay, indicating a role in JUNV infection. Therefore DC- and L- SIGN can act as a novel attachment factors that mediate entry of JUNV. However, a number of cell-surface molecules bind viral envelope glycoproteins without mediating entry. Instead, they serve as capture receptors that disseminate viral particles to target organs or susceptible cells. In this study we demonstrate that the human C type lectins hL-SIGN and hDC-SIGN enhances transduction by JUNV pseudovirus particles in cells devoid of the JUNV receptor, hTfR1, indicating that this lectins can mediate virus entry in the absence of the virus cellular receptor. This represents an important contribution to the characterization of arenavirus replication cycle. Altogether, this study characterizes the endocytic pathway utilized by the arenavirus JUNV.