Fig. 4

IL-33 serves as the primary SASP secreted by senescent fibroblasts. A Volcano plot of differentially expressed genes between senescent fibroblasts and control group in the scRNA-seq dataset, showing representative SASP expression levels. B Schematic of integrated transcriptomic analysis, including gene sets and Venn analysis results. C Expression levels of commonly highly expressed genes across different gene sets, in Log₂FC units, with IL-33 being the most highly expressed gene. D Representative immunofluorescence co-staining experiments show that IL-33 was primarily co-localized with senescent cells, n = 3. E Western blot revealed a significant reduction in IL-33 expression levels after the removal of senescent cells, with the experiment repeated three times, and a representative image was shown. F Elisa results indicated that serum IL-33 secretion levels significantly decreased after senescent cells removal, n = 3. G t-SNE dimensionality reduction image displayed that IL-33 was primarily expressed in fibroblasts. H–K Representative immunofluorescence co-localization images of IL-33 in fibroblasts, vascular endothelial cells, and myeloid immune cells, showing that IL-33 was mainly expressed in fibroblasts. Arrows point to IL-33⁺ cells, with the experiment repeated three times. When variance was met, a t-test was used for statistical analysis between two groups, while ANOVA was used for comparisons among three or more groups. If variance wasn’t met, the Mann-Whitney U test was used. *p < 0.05, **p < 0.01, ***p < 0.001. Bars represented 100 μm (D), 50 μm (H–K)