FN9-10ELP, an ECM-Mimetic Fusion Protein, Protects Human Mesenchymal Stem Cells from Etoposide-Induced Senescence

Cellular senescence is a major barrier to the therapeutic application of human mesenchymal stem cells (hMSCs), as it compromises their proliferative capacity, differentiation potential, and regenerative efficacy. In this study, we investigated whether FN9-10ELP, a recombinant extracellular matrix (ECM)-mimetic fusion protein composed of fibronectin type III domains 9 and 10 conjugated to elastin-like polypeptides (ELPs), could attenuate etoposide-induced senescence in human turbinate-derived MSCs (hTMSCs). Premature senescence was induced by treatment with 20 µM etoposide, and the protective effects of FN9-10ELP were evaluated in terms of cell viability (using the MTT assay), senescence-associated gene expression (by RT-qPCR analysis), nuclear morphology (after staining with 4',6-diamidino-2-phenylindole (DAPI)), and SA-β-galactosidase activity. FN9-10ELP treatment significantly improved cell viability and reduced the expression of <i>senescence-associated secretory phenotype (SASP)</i> genes, including <i>interleukin-6 (IL-6)</i>, <i>interleukin-8 (IL-8),</i> and <i>plasminogen activator inhibitor-1 (PAI-1).</i> Furthermore, FN9-10ELP alleviated nuclear enlargement and decreased the proportion of SA-β-gal-positive cells, indicating suppression of the senescence phenotype. These findings demonstrate that FN9-10ELP effectively counteracts chemotherapy-induced senescence in hMSCs and highlight its potential as a promising biomaterial for regenerative medicine and anti-aging therapies.