Engineering IL-10-Overexpressing MSCs via a Non-Viral PEG-PEI Nanoplatform for Potent Therapy of Inflammatory Bowel Disease.

Genetic engineering of therapeutic cells is a key strategy to enhance cell-based therapies, yet current gene delivery methods-viral vectors, electroporation, and commercial non-viral reagents-are limited by safety concerns, high cost, operational complexity, cytotoxicity, and poor scalability. We developed a safe, efficient, low-cost, and scalable non-viral gene delivery platform using a polyethylene glycol-polyethyleneimine (PEG-PEI) copolymer to engineer mesenchymal stromal cells (MSCs) for inflammatory bowel disease (IBD) treatment. The PEG-PEI copolymer was synthesized via covalent conjugation and formed stable core-shell nanocomplexes (∼130 nm, +20 mV) that completely protected DNA at N/P ≥ 10. In primary human MSCs, this platform achieved 43.8% EGFP-positive MSCs and enhanced IL-10 and bFGF secretion by approximately 2-fold and 1.6-fold, respectively, compared to Lipofectamine 3000, without compromising cell viability or multipotency. Engineered IL-10-overexpressing MSCs (PEG-PEI-IL-10-MSCs) were constructed and evaluated in a dextran sulfate sodium-induced murine acute colitis model. PEG-PEI-IL-10-MSCs restored body weight, reduced disease activity, ameliorated colon shortening and histopathological damage with efficacy comparable to the first-line drug 5-ASA, and significantly outperformed conventionally engineered or unmodified MSCs. Mechanistically, the treatment promoted epithelial proliferation and goblet cell regeneration, drove macrophage polarization toward an M2-reparative phenotype, suppressed pro-inflammatory cytokines (TNF-α and IL-6), and selectively normalized pathological angiogenesis while preserving functional vasculature. This PEG-PEI platform effectively overcomes the critical bottleneck of difficult-to-transfect primary MSCs, providing a versatile tool for cell engineering and a foundation for next-generation synergistic cell-and-gene therapies for IBD.