Journal: Nature Communications

Article Title: Saffold virus exploits integrin αvβ8 and sulfated glycosaminoglycans as cooperative attachment receptors for infection

doi: 10.1038/s41467-025-67236-z

Figure Lengend Snippet: a Pull-down assay of SAFV-3 using heparin (left panel) and integrin αVβ8 (right panel). Heparin and Fc chimera of extracellular domains of integrin αVβ8, αVβ3, or the signal sequence (ss) of integrin αV (negative control) were prepared as complexes with magnetic beads. These complexes were incubated with SAFV-3, followed by western blot analysis of the bound virus using anti-SAFV-3 antiserum (left and right upper panels). The bottom right panel shows an image of the integrin-Fc complex on magnetic beads used for pulldown, detected using an anti-mouse IgG antibody. b Cell surface attachment assay for SAFV-3. HeLaN-WT, HeLaN-∆SLC, HeLaN-∆B8, HeLaN-∆SLC∆B8, and HeLaN-∆SLC + human AVB8 were incubated with SAFV-3, followed by RT-qPCR analysis of the bound virus. c Expression of human integrin β8 in HeLaN-∆SLC and HeLaN-∆SLC + human AVB8 cells. To compare the expression levels of integrin αVβ8 on the cell surface, HeLaN-∆SLC and HeLaN-∆SLC + human AVB8 cells were stained with anti-integrin αVβ8 antibodies and analyzed by flow cytometry. d , e Inhibition of SAFV-3 attachment to the cell surface by soluble heparin ( d ) or recombinant integrin αVβ8 ( e ). HeLaN-WT cells ( d ) or HeLaN-∆SLC + human AVB8 cells ( e ) were incubated with SAFV-3 pretreated with 1 or 10 μg of soluble heparin or recombinant integrin αVβ8, respectively. Recombinant integrin αVβ3 was the negative control. After incubation at 4 °C for 2 h, bound virus was analyzed using RT-qPCR. f HeLaN-WT, HeLaN-∆SLC, HeLaN-∆B8, HeLaN-∆SLC∆B8, and HeLaN-∆SLC + human AVB8 cells were infected with tenfold serial dilutions of SAFV-3, and viable cells were stained with crystal violet to assess infection levels. All data are representative of two independent experiments. Data in ( b , d , and e ) represent means with s.d. ( n = 3). Statistical significance was determined using a one-way ANOVA with Dunnett’s multiple comparison test. **, P < 0.01, n.s. not significant. Asterisks directly placed on bars indicate statistically significant differences compared to WT or untreated samples, while asterisks placed on the lines connecting bars denote statistically significant differences between those bars. Source data are provided as a Source Data file. Ag antigen, Fc fragment crystallizable region.

Article Snippet: Recombinant human integrin αVβ3 (3050-AV, R&D Systems) was used as a negative control.

Techniques: Pull Down Assay, Sequencing, Negative Control, Magnetic Beads, Incubation, Western Blot, Virus, Quantitative RT-PCR, Expressing, Staining, Flow Cytometry, Inhibition, Recombinant, Infection, Comparison

Journal: Nature Communications

Article Title: Saffold virus exploits integrin αvβ8 and sulfated glycosaminoglycans as cooperative attachment receptors for infection

doi: 10.1038/s41467-025-67236-z

Figure Lengend Snippet: a The graph displays the −log10-transformed RRA scores of genes enriched following infection with two SAFV-3 strains in HeLaN-∆SLC cells, analyzed using the MAGeCK software. The X -axis represents data from the screen using the SAFV-3 JPN08-356 strain, whereas the Y -axis shows results from the screen using the SAFV-3 JPN08-404 strain. The dotted line indicates the significance threshold of RRA = 0.01. Genes that met the criterion of RRA < 0.01 in both screens are highlighted in blue. The size of each dot reflects the combined enrichment across both screens, with larger dots indicating a greater sum of −log10 (RRA scores) from both experiments. b Expression of human integrin αV and integrin β8 in HeLaN-WT, HeLaN-∆AV, HeLaN-∆SLC∆AV, HeLaN-∆B8, and HeLaN-∆SLC∆B8 cells. The cells were stained with anti-integrin αV or anti-integrin αVβ8 antibodies and analyzed by flow cytometry. c HeLaN-WT, HeLaN-∆AV, HeLaN-∆B8, HeLaN-∆SLC∆AV, and HeLaN-∆SLC∆B8 cells were infected with tenfold serial dilutions of SAFV-3 and viable cells were stained with crystal violet to assess infection levels. Images are representative of two independent experiments. d Multi-step growth kinetics of SAFV-3 in HeLaN-∆B8, HeLaN-∆SLC∆B8, and HeLaN-WT cells. The cells were infected with SAFV-3 and incubated for up to 5 days. Data are presented as mean viral titers with s.d. ( n = 3). Statistical significance was determined using the two-sided Welch’s t -test. **, P < 0.01, *, P < 0.05, n.s. not significant. The dotted line indicates the limit of detection. Source data are provided as a Source Data file.

Article Snippet: For the viral binding inhibition assay, SAFV-3 (1 × 10 6 PFU/well) was pretreated with either 1 μg or 10 μg of heparin sodium salt (17513-96, Nacalai Tesque) or recombinant human integrin αVβ8 (4135-AV, R&D Systems).

Techniques: Transformation Assay, Infection, Software, Expressing, Staining, Flow Cytometry, Incubation

Journal: Nature Communications

Article Title: Saffold virus exploits integrin αvβ8 and sulfated glycosaminoglycans as cooperative attachment receptors for infection

doi: 10.1038/s41467-025-67236-z

Figure Lengend Snippet: a Western blot analysis of integrin αV (left panel) and integrin β8 (right panel) expression in BHK-21 cells. BHK-21 cells that were lentivirally transduced with either human integrin αV (BHK + human AV) or hamster integrin β8 (BHK + hamster B8) were used as positive controls. The anti-integrin αV antibody cross-reacted with both human and hamster integrin αV. Actin served as the loading control. b Expression of HS, integrin αV, and β8 in BHK-21 derivatives. BHK-21 cells were stained with anti-HS antibody (upper left panel). BHK-21 cells stably expressing human integrin αV and/or β8 (BHK + human AV, BHK + human B8, BHK + human AVB8), as well as the control cells, were stained with anti-integrin αV or anti-integrin αVβ8 antibodies. The cells were analyzed by flow cytometry. c Susceptibility analysis using SAF/UnaG in BHK-21 cells expressing human integrin αV and/or β8. UnaG-positive cells (green, upper panel) and Hoechst-stained nuclei (blue, lower panel) were imaged at 16 h post-infection. Scale bar, 200 μm. The percentage of infected cells was determined by examining at least 1000 cells. Data are representative of two independent experiments. d One-step growth kinetics of SAFV-3 in BHK + human AV, BHK + human B8, BHK + human AVB8, and control cells. The cells were infected with SAFV-3 and incubated for up to 24 h. The dotted line indicates the limit of detection. e Western blot analysis of exogenous integrin β8 expression in BHK-21 cells lentivirally transduced with either mouse or hamster integrin β8. The anti-integrin β8 antibody cross-reacted with both mouse and hamster integrin β8. Actin served as the loading control. f Susceptibility analysis using SAF/UnaG in mouse and hamster integrin β8 expressing BHK-21 cells. UnaG-positive cells (green, upper panel) and Hoechst-stained nuclei (blue, lower panel) were captured at 16 h post-infection. Scale bar, 200 μm. Images are representative of two independent experiments. Data in ( c and d ) represent means with s.d. ( n = 3). Statistical significance was determined using a one-way ANOVA with Dunnett’s multiple comparison test ( c ) and the two-sided Welch’s t -test ( d ). **, P < 0.01, *, P < 0.05, n.s. not significant. Source data are provided as a Source Data file.

Article Snippet: For the viral binding inhibition assay, SAFV-3 (1 × 10 6 PFU/well) was pretreated with either 1 μg or 10 μg of heparin sodium salt (17513-96, Nacalai Tesque) or recombinant human integrin αVβ8 (4135-AV, R&D Systems).

Techniques: Western Blot, Expressing, Transduction, Control, Staining, Stable Transfection, Flow Cytometry, Infection, Incubation, Comparison

Journal: Nature Communications

Article Title: Saffold virus exploits integrin αvβ8 and sulfated glycosaminoglycans as cooperative attachment receptors for infection

doi: 10.1038/s41467-025-67236-z

Figure Lengend Snippet: a Pull-down assay of SAFV-3 using heparin (left panel) and integrin αVβ8 (right panel). Heparin and Fc chimera of extracellular domains of integrin αVβ8, αVβ3, or the signal sequence (ss) of integrin αV (negative control) were prepared as complexes with magnetic beads. These complexes were incubated with SAFV-3, followed by western blot analysis of the bound virus using anti-SAFV-3 antiserum (left and right upper panels). The bottom right panel shows an image of the integrin-Fc complex on magnetic beads used for pulldown, detected using an anti-mouse IgG antibody. b Cell surface attachment assay for SAFV-3. HeLaN-WT, HeLaN-∆SLC, HeLaN-∆B8, HeLaN-∆SLC∆B8, and HeLaN-∆SLC + human AVB8 were incubated with SAFV-3, followed by RT-qPCR analysis of the bound virus. c Expression of human integrin β8 in HeLaN-∆SLC and HeLaN-∆SLC + human AVB8 cells. To compare the expression levels of integrin αVβ8 on the cell surface, HeLaN-∆SLC and HeLaN-∆SLC + human AVB8 cells were stained with anti-integrin αVβ8 antibodies and analyzed by flow cytometry. d , e Inhibition of SAFV-3 attachment to the cell surface by soluble heparin ( d ) or recombinant integrin αVβ8 ( e ). HeLaN-WT cells ( d ) or HeLaN-∆SLC + human AVB8 cells ( e ) were incubated with SAFV-3 pretreated with 1 or 10 μg of soluble heparin or recombinant integrin αVβ8, respectively. Recombinant integrin αVβ3 was the negative control. After incubation at 4 °C for 2 h, bound virus was analyzed using RT-qPCR. f HeLaN-WT, HeLaN-∆SLC, HeLaN-∆B8, HeLaN-∆SLC∆B8, and HeLaN-∆SLC + human AVB8 cells were infected with tenfold serial dilutions of SAFV-3, and viable cells were stained with crystal violet to assess infection levels. All data are representative of two independent experiments. Data in ( b , d , and e ) represent means with s.d. ( n = 3). Statistical significance was determined using a one-way ANOVA with Dunnett’s multiple comparison test. **, P < 0.01, n.s. not significant. Asterisks directly placed on bars indicate statistically significant differences compared to WT or untreated samples, while asterisks placed on the lines connecting bars denote statistically significant differences between those bars. Source data are provided as a Source Data file. Ag antigen, Fc fragment crystallizable region.

Article Snippet: For the viral binding inhibition assay, SAFV-3 (1 × 10 6 PFU/well) was pretreated with either 1 μg or 10 μg of heparin sodium salt (17513-96, Nacalai Tesque) or recombinant human integrin αVβ8 (4135-AV, R&D Systems).

Techniques: Pull Down Assay, Sequencing, Negative Control, Magnetic Beads, Incubation, Western Blot, Virus, Quantitative RT-PCR, Expressing, Staining, Flow Cytometry, Inhibition, Recombinant, Infection, Comparison

Journal: Nature Communications

Article Title: Saffold virus exploits integrin αvβ8 and sulfated glycosaminoglycans as cooperative attachment receptors for infection

doi: 10.1038/s41467-025-67236-z

Figure Lengend Snippet: a Expression of HS and human integrin β8 in BHK-WT, BHK-∆SLC, BHK + human AVB8, BHK-∆SLC + human AVB8, and revertant cells expressing human SLC35B2 (BHK-∆SLC + human AVB8 + SLC). The cells were stained with anti-HS or anti-integrin αVβ8 antibodies and analyzed by flow cytometry. b Cell surface attachment assay for SAFV-3. BHK-WT and BHK-∆SLC cells were incubated with SAFV-3 at 4 °C for 2 h. Viral binding to HS was assessed by RT-qPCR quantification of cell-bound virus ( n = 3). c Susceptibility analysis using SAF/UnaG in BHK + human AVB8, BHK-∆SLC + human AVB8, and BHK-∆SLC + human AVB8 + SLC cells. The cells used in this experiment were sorted to equalize the surface expression levels of integrin αVβ8 between BHK + human AVB8 and BHK-∆SLC + human AVB8 cells. UnaG-positive cells (green) and nuclei stained with Hoechst (blue) were imaged at 16 h post-infection. The percentage of infected cells was determined by examining at least 800 cells/well ( n = 4). Scale bar, 200 μm. d Cell surface attachment assay for SAFV-3 in BHK + human AVB8, BHK-∆SLC + human AVB8, and BHK-∆SLC + human AVB8 + SLC cells ( n = 3). Bar graphs in ( b– d ) are presented as means with s.d. Statistical significance was determined using the two-sided Welch’s t -test ( b ) and a one-way ANOVA with Dunnett’s multiple comparison test ( c , d ). **, P < 0.01, *, P < 0.05. All data are representative of two independent experiments. Source data are provided as a Source Data file.

Article Snippet: For the viral binding inhibition assay, SAFV-3 (1 × 10 6 PFU/well) was pretreated with either 1 μg or 10 μg of heparin sodium salt (17513-96, Nacalai Tesque) or recombinant human integrin αVβ8 (4135-AV, R&D Systems).

Techniques: Expressing, Staining, Flow Cytometry, Incubation, Binding Assay, Quantitative RT-PCR, Virus, Infection, Comparison

Journal: Nature Communications

Article Title: Saffold virus exploits integrin αvβ8 and sulfated glycosaminoglycans as cooperative attachment receptors for infection

doi: 10.1038/s41467-025-67236-z

Figure Lengend Snippet: Sulfated GAGs and integrin αVβ8 function as interconnected dual receptors for SAFV infection in HeLa-N cells. SAFV can directly bind to either sulfated GAGs or integrin αVβ8, while a portion of viruses bound to sulfated GAGs subsequently interact with integrin αVβ8. In addition, the data suggest the existence of a downstream molecule (factor X) required for an unspecified step in the viral entry process following sulfated GAGs binding.

Article Snippet: For the viral binding inhibition assay, SAFV-3 (1 × 10 6 PFU/well) was pretreated with either 1 μg or 10 μg of heparin sodium salt (17513-96, Nacalai Tesque) or recombinant human integrin αVβ8 (4135-AV, R&D Systems).

Techniques: Infection, Binding Assay