Fig 1: Comparison of platelet morphology with and without SARS-CoV-2 S protein.A DIC images of platelets without (Control) and pre-incubated with 20 µg/ml S protein (Spike) on a collagen I support. * indicates collagen I fibers. B DIC images of platelets without and pre-incubated with S on a poly-L-lysine support. C DIC images of platelets without and pre-incubated with S protein on a fibronectin support. Scale bar: 5 µm (A–C). D Quantification of the aspect ratio of platelets (major axis/minor axis) on different coated surfaces, without and in the presence of S protein. The median aspect ratio is shown below the corresponding violin plot. The significance was determined by two-tailed Mann–Whitney U test. Number of platelets (collagen control: 442, collagen spike: 391, Poly-L-lysine control: 343, Poly-L-lysine spike: 430, Fibronectin control: 505, Fibronectin spike: 446) examined over at least three independent experiments from different donors. Each dot represents the value from a single platelet. E Quantification of the circularity of platelets on different coated surfaces, without and in the presence of S protein. The median circularity is shown below the corresponding violin plot. The significance was determined by two-tailed Mann–Whitney U test. Number of platelets (collagen control: 442, collagen spike: 391, Poly-L-lysine control: 343, Poly-L-lysine spike: 430, Fibronectin control: 505, Fibronectin spike: 446) examined over at least 3 independent experiments from different donors. Each dot represents the value from a single platelet. F Comparison of platelet activation, incubated with and without S protein, on Poly-L-Lysine (left), and on Fibronectin (right) Platelets with amoeba-like morphologies were defined as activated platelets. The median percentage of the activation is shown below the corresponding dot plot. The significance was determined by two-tailed Mann–Whitney U test. Number of platelets (collagen control: 442, collagen spike: 391, Poly-L-lysine control: 343, Poly-L-lysine spike: 430, Fibronectin control: 505, Fibronectin spike: 446) examined over at least three independent experiments from different donors. Each dot represents the value from a series of experiment. G Sandwich ELISA assay detecting PF4 release in the absence and presence of S protein. The mean ± SD is shown below the corresponding dot plot. The significance was determined by two-tailed Mann–Whitney U test. n = 3 independent experiments from n = 3 different donors. Source data are available as a Source Data file.
Fig 2: SOCS3 overexpression reversed the effects of PF4 silencing on the EMT and tube formation in HTR-8/SVneo cells. (A) Western blotting was used to detect E-cadherin, N-cadherin, Vimentin expression. (B) Representative images of immunofluorescence assay for E-cadherin. (C) Tube formation assay was used to detect cell angiogenesis. (D) Western blotting was used to measure SOCS3 and p/t-STAT3 expression. ***P <0.001 vs. Control group. ##P <0.01 and ###P <0.001 vs. shRNA-PF4 group. ∆∆P <0.01, ∆∆∆P <0.001 vs. shRNA-PF4+ Ov-SOCS3group.
Fig 3: PF4 silencing inhibited SOCS3 and thus activated STAT3 expression. (A) Western blotting was used to detect SOCS3 and p/t-STAT3 expression. (B) Western blotting was used to examine the transfection efficacy of SOCS3 overexpression plasmids. ***P <0.001 vs. Control group. ###P <0.001 vs. shRNA-NC group.
Fig 4: SOCS3 overexpression reversed the effects of PF4 silencing on the invasion and migration in HTR-8/SVneo cells. (A) Wound healing assay was used to detect cell migration. (B) Transwell assay was used to detect cell invasion. (C) Western blotting was used to detect MMP2 and MMP9 expression. ***P <0.001 vs. Control group. ##P <0.01 and ###P <0.001 vs. shRNA-PF4 group. ∆∆P <0.01, ∆∆∆P <0.001 vs. shRNA-PF4+ Ov-SOCS3group.
Fig 5: PF4 silencing promoted the EMT and tube formation in HTR-8/SVneo cells. (A) Western blotting was used to detect E-cadherin, N-cadherin, Vimentin expression. (B) Representative images of immunofluorescence assay for E-cadherin. (C) Tube formation assay was used to detect cell angiogenesis. ***P <0.001 vs. Control group. ###P <0.001 vs. shRNA-NC group.
Supplier Page from Abcam for Human PF4 ELISA Kit, Fluorescent