Leukemia-derived exosomes induce immunosuppression of dendritic cell function via TGFB2-MRPL58 axis.

OBJECTIVES

To elucidate the mechanisms by which leukemia-derived exosomes induce immunosuppression in dendritic cells (DCs) and identify potential therapeutic targets.

METHODS

The optimal exosome dosage (20 µg/ml) for DC treatment was determined via gradient concentration experiments. Transcriptomics and qPCR validation explored molecular pathways. DC phenotype was assessed for maturation markers (CD83/CD86), antigen presentation (CD1a), and immune receptors (TLR2). Cytokine levels (IL-6, IL-17, TNF-α, IL-4) were quantified. Multi-omics analysis identified key signaling pathways. Clinical validation utilized samples from AML patients.

RESULTS

Exosome treatment induced broad DC immunosuppression, characterized by significant downregulation of pro-inflammatory cytokines (IL-6, IL-17, TNF-α) and upregulation of anti-inflammatory IL-4. Phenotypic analysis revealed selective inhibition of CD1a and TLR2, while maturation markers (CD83/CD86) remained unaltered. Multi-omics identified TNF-β signaling as the primary immunosuppressive pathway. qPCR confirmed elevated TGF-β2 and mitochondrial ribosomal protein MRPL58, alongside reduced TLR2. Clinical studies in AML patients validated upregulation of TGF-β2, MRPL58, and exosomal markers. Exosomes impaired DC antigen presentation, immune response, and metabolic activity.

DISCUSSION: MRPL58 is a novel mediator of exosome-driven immunosuppression, implicating metabolic reprograming. Selective CD1a/TLR2 inhibition suggests exosomes evade immune detection while permitting DC maturation, a strategy favoring leukemia immune escape. Targeting exosome-DC interactions (e.g. blocking exosomal signals or MRPL58) may restore anti-tumor immunity.

CONCLUSION

Leukemia exosomes suppress DC function primarily through MRPL58-associated metabolic modulation and TNF-β signaling. MRPL58 represents a promising therapeutic target. Disrupting exosome-mediated immunosuppression could enhance DC-based vaccines and combination immunotherapies for leukemia.