Fig. 7: VPg Proc1-saRNA alleviates graft-versus-host disease.

A Diagram depicting how VPg Proc1 saRNA activates PAR1 to modulate allogeneic T-cell responses and protect alveolar epithelial cells from autologous IgG-mediated injury, thereby alleviating chronic GVHD. B Mouse tracheal epithelial cells (TEC; 10⁷ cells) were transfected with 10 μg saRNA- or mRNA-LNP, and Proc1 protein expression was monitored over 28 days to estimate APC protein half-life. C, D Kaplan–Meier survival analysis and clinical scoring (weight loss, activity, posture, fur, and skin integrity) in aGVHD mice monitored for 14 weeks following BMT. E Schematic of chronic GVHD lung-injury model: B10.BR recipients received 0.2 μg/kg VPg Proc1 saRNA by intratracheal inhalation, followed by 12.5 Gy conditioning and transplantation with B6 bone marrow (4 × 10⁶) and T cells (1 × 10⁶). Lung fibrosis was assessed over 8 weeks. F Representative 3D immunofluorescence images from three independent experiments showing VPg and PROC1 protein in lung airways on day 3 post-BMT, confirming VPg Proc1 saRNA-LNP replication in vivo. G, H Flow cytometry analysis of GC B cells, T_FH cells and T_FR cells in lung-draining lymph nodes at day 7 post-BMT; representative plots from independent biological replicates are shown. I Autoantibodies in bronchoalveolar lavage fluid (anti-dsDNA IgG/IgM/IgA/IgE, anti-SSB, anti-SSA IgG/IgA) measured by ELISA at day 14 post-BMT. J Representative H&E, Masson and immunohistochemistry images showing lung tissue injury, fibrosis and immunoglobulin deposition at day 56 post-BMT, demonstrating the therapeutic efficacy of VPg Proc1 saRNA-LNP. All cell-based experiments were performed independently three times, and all animal data represent measurements from individual animals; representative immunofluorescence. All data are presented as mean ± standard deviation (s.d.). AUC comparison of aGVHD clinical scores among four treatment groups was performed using one-way ANOVA followed by Tukey’s multiple-comparisons test (D, n = 15). One-way ANOVA with Tukey’s post hoc test was used for flow cytometry and ELISA analyses (G, n = 7; H, n = 7; I, n = 7). Proc1 protein half-life was analyzed using the Welch t-test (B, n = 6). Survival analysis used the Gehan–Breslow–Wilcoxon test (C, n = 15). Exact p-values are indicated within the figure. Figure 7A, E were created in BioRender. Dwad, D. (2025) https://BioRender.com/xwlgkhh. Source data are provided as a Source Data file.