Background
Adipose tissue-derived stem cell (ADSC) transplantation has been shown to be effective for the management of severe liver disorders. Preactivation of ADSCs enhanced their therapeutic efficacy. However, these effects have not yet been examined in relation to cholestatic liver injury.
Conclusion
In conclusion, our results suggest that TNF-α/IL-1β pretreatment enhances the efficacy of hADSCs in mice with cholestatic liver injury, partially through the COX-2/PGE2 pathway.
Methods
In the present study, a cholestatic liver injury model was established by bile duct ligation (BDL) in male C57BL/6 mice. Human ADSCs (hADSCs) with or without tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β) pretreatment were administrated into the mice via tail vein injections. The efficacy of hADSCs on BDL-induced liver injury was assessed by histological staining, real-time quantitative PCR (RT-qPCR), Western blot, and enzyme-linked immune sorbent assay (ELISA). In vitro, the effects of hADSC conditioned medium on the activation of hepatic stellate cells (HSCs) were investigated. Small interfering RNA (siRNA) was used to knock down cyclooxygenase-2 (COX-2) in hADSCs.
Results
TNF-α/IL-1β preconditioning could downregulate immunogenic gene expression and enhance the engraftment efficiency of hADSCs. Compared to control hADSCs (C-hADSCs), TNF-α/IL-1β-pretreated hADSCs (P-hADSCs) significantly alleviated BDL-induced liver injury, as demonstrated by reduced hepatic cell death, attenuated infiltration of Ly6G + neutrophils, and decreased expression of pro-inflammatory cytokines TNF-α, IL-1β, C-X-C motif chemokine ligand 1 (CXCL1), and C-X-C motif chemokine ligand 2 (CXCL2). Moreover, P-hADSCs significantly delayed the development of BDL-induced liver fibrosis. In vitro, conditioned medium from P-hADSCs significantly inhibited HSC activation compared to that from C-hADSCs. Mechanistically, TNF-α/IL-1β upregulated COX-2 expression and increased prostaglandin E2 (PGE2) secretion. The blockage of COX-2 by siRNA transfection reversed the benefits of P-hADSCs for PGE2 production, HSC activation, and liver fibrosis progression.