Pretreatment of exosomes derived from hUCMSCs with TNF-α ameliorates acute liver failure by inhibiting the activation of NLRP3 in macrophage

Aims: The management of acute liver failure (ALF) is a major challenge worldwide. The current study aimed to determine the therapeutic potential of TNF-alpha pretreatment of umbilical cord mesenchymal stem cell-derived exosomes (T-Exo) in ALF. Main methods: Here, we enriched T-Exo and untreated exosomes (Exo), them were measured by nanoparticle tracking analysis (NTA) for particle size detection and identified surface marker by Western blot and flow cytometry. Then the cell proliferation was detected by CCK-8 and the effect of T-Exo on the expression levels of pro-inflammatory cytokines was tested by ELISA. ALF mouse models were induced by LPS and D-GalN. H&E staining, immunohistochemistry, and Western blot were used to detect the effect of T-Exo on the levels of NLRP3 and other inflammation-related pathway proteins. qPCR was used to detect the expression level of microRNA-299-3p in T-Exo and its transfer to macrophages. Laser confocal microscopy was used to detect colocalization of exosomes,Golgi and NLRP3 in macrophages. Key findings: Our study shows that T-Exo can reduce serum ALT, AST and proinflammatory cytokines level and inhibit activation of NLRP3 inflammation-associated pathway proteins. T-Exo treatment reduces pathological liver damage caused by ALF. Anti-inflammatory-related miRNA-299-3p is up-regulated in TNF-alpha-stimulated MSCs and selectively packaged into exosomes for role in exosomal treatment. And conducted preliminary exploration and hypothesis on the specific mechanism of this effect. Significance: These in vitro and in vivo studies indicate that T-Exo attenuates inflammatory damage caused by ALF and promotes liver tissue repair by inhibiting the activation of the NLRP3 pathway.