Fig 2: Effects of MMP8 treatment on pulmonary glycocalyx in vitro. (A) UMAP representation of scRNA-seq analysis from healthy human lung tissue, identifying 14 distinct cell clusters. (B) Feature Plot displaying the glycocalyx module score (GMS) and (C) degrading enzyme module score (DEMS), calculated based on the gene sets outlined in Supplementary Figure S2 (Figure S2B,C). (D) Dot plot showing syndecan gene expression, with dot size indicating the percentage of expressing cells and color intensity reflecting average expression levels. (E) Immunofluorescence imaging of untreated and rhMMP8-treated EpiAlveolar™ 3D lung models, incorporating alveolar epithelial cells (EpiCs), fibroblasts (FBs), and endothelial cells (ECs). The 20× magnification images display DAPI-stained nuclei (blue) and SDC1 fluorescence (red). (F) ELISA-based quantitative analysis of SDC1, SDC4, and HA in EpiAlveolar™ model supernatants, with significant differences (p < 0.05) marked in red. (G) SAECs treated with APMA, rhMMP8 alone, and activated rhMMP8, with SDC1, SDC4, and HA levels in supernatants analyzed via ELISA. Statistical significance was assessed using two-tailed unpaired t-tests and the Kruskal–Wallis test followed by Dunn’s multiple comparisons, with significant results (adj. p < 0.05) highlighted in red.

Fig 3: Serum levels of glycocalyx constituents and MMP8 together with SDC1 correlation in burn patients. Systemic levels of SDC1 (A), SDC4 (B), HA (C), HS (D), and MMP8 (E) were quantified in healthy controls and burn patients over a 21-day follow-up. Data analysis was performed using Kruskal–Wallis tests, complemented by Dunn’s multiple comparisons. Data are presented as minimum to maximum boxplots including all data points. Time points with statistical significance (adjusted p-value < 0.05) are marked in red. (F) Pearson’s correlation analysis between MMP8 and SDC1 serum levels in burn patients over various time points, with R2 values and corresponding p-values provided.