Invigorating human MSCs for transplantation therapy via Nrf2/DKK1 co- stimulation in a mice acute-on-chronic liver failure model

Boosting stem cell resilience against an extrinsically harsh recipient environment is critical to therapeutic efficiency of stem cell-based transplantation innovations in liver disease contexts. We aimed to establish the efficacy of a transient plasmid-based preconditioning strategy to boost mesenchymal stromal cells (MSCs) capacity for anti-inflammation/antioxidant defense and paracrine actions on recipient hepatocytes. In MSCs, the master antioxidant regulator Nrf2 was found to bind directly to the antioxidant response element in the DKK1 promoter region. Activation of Nrf2 and DKK1 enhanced the anti-stress capacities of MSCs in vitro. In an acute-on-chronic liver failure (ACLF) murine model, transient co-overexpression of Nrf2 and DKK1 via plasmid transfection markedly improved MSC resilience against inflammatory and oxidative assaults, boosted MSC transplantation efficacy and promoted recipient liver regeneration because of a shift from the activation of the anti-regenerative IFN-{gamma}/STAT1 pathway to the pro-regenerative IL-6/STAT3 pathway in the liver. Moreover, specific ablation of DKK1 receptor CKAP4 but not LRP6 in recipient hepatocytes nullified therapeutic benefits from MSC transplantation. In long-term observations, tumorigenicity was undetected in mice following transplantation of such transiently preconditioned MCSs. In conclusion, co-stimulation of Nrf2/DKK1 signaling decisively and safely improves the efficacy of human MSC-based therapies in mouse ACLF models through apparently CKAP4-dependent paracrine mechanisms.