Abstract:Objective To evaluate the molecular mechanisms by which dendritic cells (DCs) detect variations in the extracellular mechanical microenvironment and dynamically adjust their migration behavior. Methods Hydrogel substrates with varied stiffness were constructed to investigate the influence of the mechanical microenvironment on the DC migration behavior. A fibrotic rat liver model was established in combination with immunohistochemistry experiments to investigate the effect of liver fibrosis on the DC migration capability. Furthermore, potential key molecules involved in the mechanical sensing cascade during DC migration were analyzed using single-cell sequencing data from human/mouse fibrotic livers. Moreover, RT-qPCR was used to examine the expression levels of these key molecules in mouse DCs on substrates of different stiffness. Results The migration capability of DCs on stiff substrates was significantly lower than that on soft substrates. The DC infiltration in fibrotic rat livers increased, and 682 differentially expressed genes (DEGs) were observed between liver-infiltrating DCs from cirrhosis patients and normal individuals. Furthermore, focusing on genes relevant to cytoskeleton regulation and migration based on KEGG and GO pathway enrichment analysis, 12 potential key molecules mediating stiffness detection during DC migration were identified. Among these, the expression levels of AIF1, GPR65, MYL12B, RAC1, and RHOG were upregulated in patients with liver cirrhosis, whereas those of ACTB, ACTG1, ARF6, CDC42, COTL1, PFN1, and TMSB10 were downregulated. Subsequently, the expression levels of ACTB and CDC42 were downregulated in mouse DCs grown on stiff substrates. This was consistent with the circumstance of liver-infiltrating DC in human cirrhotic patients. Conclusions Liver fibrosis potentially impairs DC migration and thereby, results in increased DC infiltration. ACTB and CDC42 are potential regulators of DC stiffness during migration. This study has provided a theoretical basis and an inspiring novel strategy for optimizing DC-mediated antitumor immune functions.