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Báo cáo y học: " Incorporation of podoplanin into HIV released from HEK-293T cells, but not PBMC, is required for efficient binding to the attachment factor CLEC-2"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Retrovirology cung cấp cho các bạn kiến thức về ngành y đề tài: Incorporation of podoplanin into HIV released from HEK-293T cells, but not PBMC, is required for efficient binding to the attachment factor CLEC-2. | Chaipan et al. Retrovirology 2010 7 47 http www.retrovirology.eom content 7 1 47 gtr RETR0VIR0L0GY RESEARCH Open Access Incorporation of podoplanin into HIV released from HEK-293T cells but not PBMC is required for efficient binding to the attachment factor CLEC-2 Chawaree Chaipan21 2 Imke Steffen23 Theodros Solomon Tsegaye23 Stephanie Bertram3 Ilona Glowacka3 Yukinari Kato4 Jan Schmokel5 Jan Munch5 Graham Simmons6 Rita Gerardy-Schahn7 and Stefan Pohlmann 1 2 3 Abstract Background Platelets are associated with HIV in the blood of infected individuals and might modulate viral dissemination particularly if the virus is directly transmitted into the bloodstream. The C-type lectin DC-SIGN and the novel HIV attachment factor CLEC-2 are expressed by platelets and facilitate HIV transmission from platelets to T-cells. Here we studied the molecular mechanisms behind CLEC-2-mediated HIV-1 transmission. Results Binding studies with soluble proteins indicated that CLEC-2 in contrast to DC-SIGN does not recognize the viral envelope protein but a cellular factor expressed on kidney-derived 293T cells. Subsequent analyses revealed that the cellular mucin-like membranous glycoprotein podoplanin a CLEC-2 ligand was expressed on 293T cells and incorporated into virions released from these cells. Knock-down of podoplanin in 293T cells by shRNA showed that virion incorporation of podoplanin was required for efficient CLEC-2-dependent HIV-1 interactions with cell lines and platelets. Flow cytometry revealed no evidence for podoplanin expression on viable T-cells and peripheral blood mononuclear cells PBMC . Podoplanin was also not detected on HIV-1 infected T-cells. However apoptotic bystander cells in HIV-1 infected cultures reacted with anti-podoplanin antibodies and similar results were obtained upon induction of apoptosis in a cell line and in PBMCs suggesting an unexpected link between apoptosis and podoplanin expression. Despite the absence of detectable podoplanin expression .