Genetic Engineering of Umbilical Cord-Derived Mesenchymal Stem Cells to Enhance BMP-2 Secretion via Signal Peptide Optimization

<b>Background/Objectives</b>: Mesenchymal stem cells (MSCs) are recognized for their therapeutic potential due to their ability to secrete bioactive molecules. Among these secreted factors, bone morphogenetic protein-2 (BMP-2) is known as a secreted factor that plays a crucial role in bone healing and regeneration. However, MSCs naturally secrete only small amounts of BMP-2. To improve the bone healing capacity of MSCs, it is essential to enhance the secretion of BMP-2 in MSCs. One approach that can be used to achieve this goal is by genetically engineering MSCs. Incorporating signal peptides (SPs) into the inserted gene sequence can significantly improve protein secretion efficiency. In this proof-of-concept study, we explored the role of SPs in optimizing BMP-2 secretion in umbilical cord-derived MSCs; <b>Methods</b>: Three human-derived SPs, namely glial-derived neurotrophic factor (GDNF), chemotactic antibacterial glycoprotein 7 (CAP7), and platelet-derived growth factor subunit B (PDGFB), were selected. Transfection of MSCs was performed using polyethylenimine, Lipofectamine 2000^®, and Lipofectamine 3000^®. Transfection efficiency confirmed based on Green Fluorescence Protein expression. BMP-2 secretion levels were quantified using an ELISA assay; <b>Results</b>: Lipofectamine 3000^® achieved the highest transfection efficiency, reaching approximately 10%. BMP-2 secretion levels varied significantly depending on the SPs used, with PDGFB yielding the highest BMP-2 concentration (279.21 ± 6.91 pg/mL), followed by GDNF (265.65 ± 11.49 pg/mL) and CAP7 (233.72 ± 32.33 pg/mL); <b>Conclusions</b>: These findings demonstrate that SP selection critically influences BMP-2 secretion efficiency in genetically engineered MSCs and underscore its potential to enhance the therapeutic applicability of MSC-based strategies for bone healing.