Lycium barbarum polysaccharides modulate SOCS-1 gene methylation and promote the maturation and migration of human monocyte-derived dendritic cells in vitro.

OBJECTIVE

To investigate the effects of Lycium barbarum polysaccharides (LBPs) on the methylation of the Suppressor of Cytokine Signalling-1 (SOCS-1) gene and the maturation and migration of human monocyte-derived dendritic cells (DCs) in vitro.

METHODS

Human monocyte-derived DCs were generated using recombinant human GM-CSF and interleukin-4 (IL-4) and treated with various concentrations of LBPs (50, 100, and 200 mg/L). SOCS-1 methylation and relative gene expression were analyzed by methylation-specific quantitative PCR (qMSP) and quantitative real-time PCR, respectively. DC surface markers were assessed by flow cytometry. Cytokine (IL-12 and IL-10) secretion was measured by enzyme-linked immunosorbent assay (ELISA). JAK2, STAT3 and STAT5 phosphorylation were assessed by Western Blot Analysis. The ability of LBPs-treated DCs to stimulate lymphocyte proliferation was evaluated in a mixed lymphocyte reaction (MLR). DC migration was tested using a Transwell assay toward MIP-3β, and CCR7 expression was quantified by real-time PCR.

RESULTS

LBPs treatment upregulated SOCS-1 gene methylation and increased the expression of maturation markers (CD80, CD83, HLA-DR) and IL-12 production in a dose-dependent manner. Conversely, SOCS-1 expression and IL-10 secretion were downregulated. Furthermore, LBPs-treated DCs enhanced allogeneic lymphocyte proliferation. A significant increase in DC migration toward MIP-3β and CCR7 expression was observed in the 200 mg/L LBPs group compared to the control.

CONCLUSION

These findings indicate that LBPs are associated with increased SOCS-1 methylation and enhanced maturation and migratory capacity of human monocyte-derived DCs in vitro. Notably, to our knowledge, this is the first report demonstrating that a plant-derived polysaccharide can modulate SOCS-1 gene methylation, suggesting a potential epigenetic mechanism underlying the immunomodulatory activity of LBPs.