Extracellular vesicles  produced by bone marrow mesenchymal stem cells overexpressing programmed death‐ligand 1 ameliorate dextran sodium sulfate‐induced ulcerative colitis in rats by regulating Th17/Treg cell balance through PTEN/PI3K/AKT/mTOR axis

Programmed death‐ligand 1 (PD‐L1) was involved in regulating Th17/Treg cell balance in ulcerative colitis (UC). Extracellular vesicles (EVs) from genetically modified bone marrow mesenchymal stem cells (BMSCs) can serve as a stable delivery system to overexpress PD‐L1. The study was designed to evaluate the therapeutic mechanism of BMSC‐EVs overexpressing PD‐L1 (PD‐L1‐EVs) on ulcerative colitis.