Introduction: Chronic liver injury, often characterized by sustained inflammation, metabolic dysfunction, and fibrotic remodeling, poses a major global health challenge with limited effective therapies. Mesenchymal stem cells (MSCs) offer regenerative and immunomodulatory benefits in liver disease, but their therapeutic efficacy remains suboptimal. MicroRNA-27b (miR-27b) has been implicated in metabolic regulation and inflammation. This study investigates whether overexpression of miR-27b enhances the therapeutic potential of human adipose-derived MSCs (hAD-MSCs) in a murine model of thioacetamide (TAA)-induced chronic liver fibrosis.

Methods: Human AD-MSCs were engineered to overexpress miR-27b using chemically modified miRNA mimics. ATP levels were quantified in transfected MSCs to assess metabolic enhancement. A chronic liver injury model was established by administering intraperitoneal injections of TAA (150 mg/kg in PBS) twice weekly for 6 weeks in NOD/SCID mice. Engineered hAD-MSCs (5×10⁶ cells in 200 µL PBS) were infused via tail vein at week 6. Histological analysis (H&E staining), immunoblotting for fibrosis and metabolic markers (e.g., α-SMA, fibronectin, CDH1, p-STAT3, PPARGC1α), and inflammatory profiling were conducted at week 9.

Results: miR-27b overexpression significantly elevated ATP production in hAD-MSCs (~27-fold vs. control), indicating enhanced bioenergetic status. Histological analysis revealed marked improvement in liver architecture and reduced fibrosis in the TAA + hAD-MSC group. Western blotting confirmed decreased expression of α-SMA and fibronectin, restored epithelial marker CDH1, and normalization of mitochondrial regulator PPARGC1α and p-STAT3 signaling. These results suggest that miR-27b-MSCs exert anti-fibrotic, metabolic, and immunoregulatory effects in vivo.

Conclusion: Our findings demonstrate that miR-27b engineering enhances the therapeutic potency of hAD-MSCs in chronic liver injury by promoting mitochondrial function and modulating fibrotic and inflammatory pathways. This strategy holds translational promise for advancing MSC-based therapies in liver fibrosis and metabolic liver disorders.