Establishment of iPSC-Derived MSCs Expressing hsa-miR-4662a-5p for Enhanced Immune Modulation in Graft-Versus-Host Disease (GVHD).

The immune-modulatory effects of mesenchymal stromal cells (MSCs) are widely used to treat inflammatory disorders, with indoleamine 2,4-dioxygenase-1 (IDO-1) playing a pivotal role in suppressing stimulated T-cell proliferation. Taking that three-dimensional (3D) cultures enhance MSCs' anti-inflammatory properties compared with two-dimensional (2D) cultures, the differentially expressed miRNAs were examined. Thus, we identified hsa-miR-4662a-5p (miR-4662a) as a key inducer of IDO-1 via its suppression of bridging integrator-1 (BIN-1), a negative regulator of the IDO-1 gene. The IDO-1-inducing potential of miR-4662a was conserved across primary MSCs from various donors and sources but exhibited variability. Notably, iPSC-derived MSCs (iMSCs) demonstrated superior IDO-1 induction and immune-modulatory efficacy compared with their donor-matched primary MSCs. Accordingly, iMSCs expressing miR-4662a (4662a/iMSC) exhibited stronger suppressive effects on T-cell proliferation and more potent suppressive effects on graft-versus-host disease (GVHD), improving survival rates and reducing tissue damage in the liver and gut. Our results point to the therapeutic potential of standardized, off-the-shelf 4662a/iMSC as a robust immune-modulating cell therapy for GVHD.