Fig 2: Administration of PNSC928 significantly improve the inflammatory outcomes of ARDS mice. (A) A schematic representation illustrating PNSC928 administration. (B-G) Serum concentrations of proinflammatory cytokines by ELISA assays. (B) IL-1β, (C) IL-6, (D) IL-15, (E) IL-18, (F) TNF-α, and (G) IFN-γ. (H) Body weights of mice measured at 0, 1, and 2 days. (I) pO2 levels in mice measured at 0, 1, and 2 days. (J) Effects of PNSC928 on the expression levels of IL-1B, IL-6, IL-15, IL-18, TNFA, and IFNG. (K) Effects of PNSC928 on the expression levels of S100A8, CtBP2, ICAM1, SPP1, FBN1, and SPSB1. (L) Representative H&E staining images of lung from control, ARDS, PNSC928 groups of mice. Bars = 100 μm. (M) Quantification of histological scores. Images in (L) were quantified. n = 3 for each experiment. ns: no significant difference. *P < 0.05; **P < 0.01; ***P < 0.001

Fig 3: Proinflammatory cytokine genes were predominately upregulated in ARDS mice. (A) Experimental design: RNA-Seq analysis to identify differentially expressed genes (DGEs) in ARDS mice. (B) Volcano plot displaying RNA-Seq results. (C) Heatmap of top 20 upregulated genes and top 10 downregulated genes in ARDS lung tissues. (D) Biological processes of DGEs revealed by gene ontology (GO) analysis. (E and F) Verification of 12 DGEs by RT-qPCR analysis (n = 3). (E) IL-1B, IL-6, IL-15, IL-18, TNFA, and IFNG. (F) S100A8, CtBP2, ICAM1, SPP1, FBN1, and SPSB1. **P < 0.01; ***P < 0.001

Fig 4: Inhibitors of CtBP2, p300, and NF-κB exhibited cytotoxicity in vivo. C57BL/6 mice were administrated with MTOB (400 and 800 mg/kg), NSC95397 (2 and 4 mg/kg), C646 (5 and 10 mg/kg), A-485 (40 and 80 mg/kg), TPCA1 (10 and 20 mg/kg), BOT64 (30 and 60 mg/kg) for a duration of 6 days (n = 10 for each group). (A-F) Body weights were measured every two days. (G-K) Serum concentrations of different groups of mice. (G) IL-1β, (H) IL-6, (I) IL-15, (J) IL-18, and (K) TNF-α. *P < 0.05

Fig 5: A schematic model of targeting CtBP2-p300 by PNSC928 to suppress the expression of proinflammatory cytokine genes and improve ARDS outcomes. (A) This schematic model illustrates the role of the CtBP2-p300-NF-κB complex in the activation of proinflammatory cytokine genes. CtBP2 forms a transcriptional complex with p300 and NF-κB subunits, leading to the activation of proinflammatory cytokine genes (IL-1B, IL-6, IL-15, IL-18, TNFA, and IFNG). The induction of these proinflammatory cytokines promotes the inflammatory response, contributing to the pathogenesis of ARDS. (B) This schematic model demonstrates the mechanism of action of PNSC928 in targeting the CtBP2-p300 complex. PNSC928 specifically disrupts the interaction between CtBP2 and p300, effectively suppressing the expression of proinflammatory cytokine genes. This intervention ultimately leads to improved outcomes in ARDS by mitigating the inflammatory response