S100A8/A9 Priming Alters Translational Related Proteins and Upregulates Pro‑Regenerative Factors in Mesenchymal Stromal Cells

Background: Non-healing wounds cause profound suffering of patients and a huge economic burden on society. Current research attempts to refine MSC-based therapies for this type of difficult-to-treat wounds. We earlier reported that injection of S100A8/A9 primed MSCs into the wound edge in mice accelerates wound healing compared to non-primed MSCs. We here describe a protective response of differentially expressed isoforms of genes, proteins and their potential role in the reported beneficial effects of S100A8/A9 primed MSCs on tissue repair. Methods: Adipose‐derived MSCs were characterized for specific cell surface markers using flow cytometry and assessed for their ability to differentiate into different lineages. To further investigate the mechanisms underlying the beneficial effects of S100A8/A9 primed MSCs, we employed a multi‐omics strategy that combined transcriptome, secretome, and proteome analyses. Global translational activity and a potential metabolic shift were examined using fluorescent labeling alongside seahorse‐based metabolic assays. Additionally, in silico analysis was conducted to assess the presence of the DRACH motif in mRNAs encoding these proteins, thereby evaluating their potential for cap-independent, m6A‐mediated translation. Results: Enhanced protein translation was observed in MSCs primed with S100A8/A9. Priming significantly increased the levels of the cap-independent translation initiation factor EIF3I, while reducing the cap-dependent factor EIF4A1, suggesting a shift in the mode of translation. In addition, the secretome of S100A8/A9-primed MSCs exhibited upregulation of cystatin C, a tissue protective protease inhibitor, and angiopoietin-1, an inducer of angiogenesis. Furthermore, various collagens, which serve as MSC niche-protecting proteins, were expressed at higher levels in the S100A8/A9 primed MSCs. Notably, the mRNAs corresponding to these factors contained DRACH motifs. Conclusion: We uncovered a protective response in S100A8/A9 primed MSCs that alters translation processes and increases the secretion of protective proteins, whose functions warrant further exploration. In the long term, S100A8/A9 priming holds promise for developing more effective MSC‐based therapies to enhance wound healing.